EGFR
Epidermal growth factor receptor precursor (EC 2.7.10.1) (Proto-oncogene c-ErbB-1) (Receptor tyrosine-protein kinase erbB-1) [ERBB] [ERBB1] [HER1]
Publications[править]
Type I collagen is the major structural component of lung stroma. Because of its long half-life, type I collagen undergoes post-translational modifications such as glycation during aging process. These modifications have been shown to impact the structural organization of type I collagen fibers. In the present work we evaluated the impact of collagen aging on lung carcinoma cells response to erlotinib-induced cytotoxicity and apoptosis, and on Epidermal Growth Factor Receptor (EGFR) expression and phosphorylation. To this end, experiments were performed in 2D and 3D matrix models established from type I collagen extracted from adult (10 weeks-old) and old (100 weeks-old) rat's tail tendons. Our results show that old collagen induces a significant increase in EGFR expression and phosphorylation when compared to adult collagen in 3D matrix but not in 2D coating. Such modification was associated to an increase in the IC of erlotinib in the presence of old collagen and a lower sensitivity to drug-induced apoptosis. These data suggest that collagen aging confers resistance to the cytotoxic and apoptotic effects of therapies targeting EGFR kinase function in lung carcinoma. Moreover, our data underline the importance of the 3D matrix environment in this process.
Keywords
- EGFR
- Erlotinib
- Type I collagen
- aging
- resistance
Detailed catalog of lung cancer-associated gene mutations provides valuable information for lung cancer diagnosis and treatment. In China, there has never been a wide-ranging study cataloging lung cancer-associated gene mutations. This study aims to reveal a comprehensive catalog of lung cancer gene mutations in china, focusing on EGFR, ALK, KRAS, HER2, PIK3CA, MET, BRAF, HRAS, and CTNNB1 as major targets. Additionally, we also aim to correlate smoking history, gender, and age distribution and pathological types with various types of gene mutations. A retrospective data acquisition was conducted spanning 6 years (2013-2018) among all patients who underwent lung cancer surgeries not bronchial or percutaneous lung biopsy at three major tertiary hospitals. Finally, we identified 1,729 patients who matched our inclusion criteria. 1081 patients (62.49%) harbored EGFR mutation. ALK ([i]n[/i] = 42, 2.43%), KRAS ([i]n[/i] = 201, 11.62%), CTNNB1 ([i]n[/i] = 28, 1.62%), BRAF ([i]n[/i] = 31, 1.79%), PIK3CA ([i]n[/i] = 51, 2.95%), MET ([i]n[/i] = 14, 0.81%), HER2 ([i]n[/i] = 47, 2.72%), HRAS ([i]n[/i] = 3, 0.17%), and other genes([i]n[/i] = 232, 13.4%). Females expressed 55.38% vs. males 44.62% mutations. Among subjects with known smoking histories, 32.82% smokers, 67.15% non-smokers were observed. Generally, 51.80% patients were above 60 years vs. 48.20% in younger patients. Pathological types found includes LUADs 71.11%, SQCCs 1.68%, ASC 0.75%, LCC 0.58%, SCC 0.35%, ACC 0.17%, and SC 0.06%, unclear 25.19%. We offer a detailed catalog of the distribution of lung cancer mutations. Showing how gender, smoking history, age, and pathological types are significantly related to the prevalence of lung cancer in China.
Keywords
- China
- aging
- gene mutation
- lung cancer
- pathology
- tobacco smoking
It is well established that inflammation in the body promotes organism aging, and recent studies have attributed a similar effect to senescent cells. Considering that certain pro-inflammatory cytokines can induce cellular senescence, systematically evaluating the effects of pro-inflammatory cytokines in cellular senescence is an important and urgent scientific problem, especially given the ongoing surge in aging human populations. Treating IMR90 cells and HUVECs with pro-inflammatory cytokines identified six factors able to efficiently induce cellular senescence. Of these senescence-inducing cytokines, the activity of five (namely IL-1β, IL-13, MCP-2, MIP-3α, and SDF-1α) was significantly inhibited by treatment with cetuximab (an antibody targeting epidermal growth factor receptor [[[EGF]]R]), gefitinib (a small molecule inhibitor of EGFR), and EGFR knockdown. In addition, treatment with one of the senescence-inducing cytokines, SDF-1α, significantly increased the phosphorylation levels of EGFR, as well as Erk1/2. These results suggested that pro-inflammatory cytokines induce cellular senescence by activating EGFR signaling. Next, we found that EGF treatment could also induce cellular senescence of IMR90 cells and HUVECs. Mechanically, EGF induced cellular senescence via excessive activation of Ras and the Ras-BRaf-Erk1/2 signaling axis. Moreover, EGFR activation induced IMR90 cells to secrete certain senescence-associated secretory phenotype factors (IL-8 and MMP-3). In summary, we report that certain pro-inflammatory cytokines induce cellular senescence through activation of the EGFR-Ras signaling pathway. Our study thus offers new insight into a long-ignored mechanism by which EGFR could regulate cellular senescence and suggests that growth signals themselves may catalyze aging under certain conditions.
Keywords
- EGFR
- HUVEC
- IMR90
- Ras signaling
- pro-inflammatory cytokine
- senescence
Comparison of the effectiveness and cost-effectiveness of three first-line EGFR-tyrosine kinase inhibitors (TKIs) would improve patients' clinical benefits and save costs. Using real-world data, this study attempted to directly compare the effectiveness and cost-effectiveness of first-line afatinib, erlotinib, and gefitinib. During May 2011-December 2017, all patients with non-small cell lung cancer (NSCLC) visiting a tertiary center were invited to fill out the EuroQol five-dimension (EQ-5D) questionnaires and World Health Organization Quality of Life, brief version (WHOQOL-BREF), and received follow-ups for survival and direct medical costs. A total of 379 patients with EGFR mutation-positive advanced NSCLC under first-line TKIs were enrolled for analysis. After propensity score matching for the patients receiving afatinib (n = 48), erlotinib (n = 48), and gefitinib (n = 96), we conducted the study from the payers' perspective with a lifelong time horizon. Patients receiving afatinib had the worst lifetime psychometric scores, whereas the differences in quality-adjusted life expectancy (QALE) were modest. Considering 3 treatments together, afatinib was dominated by erlotinib. Erlotinib had an incremental cost-effectiveness of US$17,960/life year and US$12,782/QALY compared with gefitinib. Acceptability curves showed that erlotinib had 58.6% and 78.9% probabilities of being cost-effective given a threshold of 1 Taiwanese per capita GDP per life year and QALY, respectively. Erlotinib appeared to be cost-effective. Lifetime psychometric scores may provide additional information for effectiveness evaluation.
MeSH Terms
- Afatinib
- Aged
- Carcinoma, Non-Small-Cell Lung
- Cost-Benefit Analysis
- Erlotinib Hydrochloride
- Female
- Gefitinib
- Humans
- Life Expectancy
- Lung Neoplasms
- Male
- Propensity Score
- Protein Kinase Inhibitors
- Quality of Life
- Survival Rate
- Taiwan
- Tertiary Care Centers
Homeostasis in adult organs involves replacement of cells from a stem cell pool maintained in specialized niches regulated by extracellular signals. This cell-to-cell communication employs signal transduction pathways allowing cells to respond with a variety of behaviors. To study these cellular behaviors, signaling must be perturbed within tissues in precise patterns, a technique recently made possible by the development of optogenetic tools. We developed tools to study signal transduction in vivo in an adult fly midgut stem cell model where signaling was regulated by the application of light. Activation was achieved by clustering of membrane receptors EGFR and Toll, while inactivation was achieved by clustering the downstream activators ERK/Rolled and NFκB/Dorsal in the cytoplasm, preventing nuclear translocation and transcriptional activation. We show that both pathways contribute to stem and transit amplifying cell numbers and affect the lifespan of adult flies. We further present new approaches to overcome overexpression phenotypes and novel methods for the integration of optogenetics into the already-established genetic toolkit of Drosophila.
MeSH Terms
- Animals
- Cell Communication
- Cell Proliferation
- Cells, Cultured
- Drosophila Proteins
- Drosophila melanogaster
- Gene Expression Regulation
- Gene Regulatory Networks
- Homeostasis
- Intestinal Mucosa
- Light
- Longevity
- Optogenetics
- Signal Transduction
- Stem Cells
Keywords
- Drosophila
- EGFR
- Toll
- optogenetics
- stem cells
Epidermal growth factor (EGF) has important physiological functions that are mediated by the epidermal growth factor receptor (EGFR); however, to date, the changes in cellular behaviours and signalling properties of EGF/EGFR with aging remain unclear in the pig tissue models. Hence, the present study used porcine hepatocytes as a model to explore this issue. The study revealed the following results: 1) EGF could activate the intra-cellular signalling pathways in a time- and dose-dependent manner both in the young- and aged-pig hepatocytes, EGF induced tyrosine phosphorylation of EGFR, signal transducers and activators of transcription 3 (STAT3), protein kinase B (AKT) and extra-cellular signal-regulated kinase 1/2 (ERK1/2). Nevertheless, the EGF's signalling ability in the aged-pig hepatocytes was significantly reduced compared with that of the young-pig hepatocytes; 2) although EGF/EGFR can still be internalised into cells in a time-dependent manner with aging, the endocytic pathway differs between the young- and aged-pig hepatocytes. Furthermore, the results of the present study indicated that caveolin may play a pivotal role in the endocytosis of EGF/EGFR in the aged-pig hepatocytes, which is different from that of EGF/EGFR's endocytosis in young-pig hepatocytes; 3) It is well-known that EGFR carried out its biological effects via two signalling pathways, cytoplasmic pathway (traditional) and nuclear pathway; however, we found that the nuclear localisation of EGFR was significantly reduced in the aged-pig hepatocytes, which indicated that EGFR may lose its nuclear pathway with aging. Collectively, the present study lays the foundation for further study regarding the biological functional changes occurring in EGF/EGFR with aging.
MeSH Terms
- Animals
- ErbB Receptors
- Signal Transduction
- Swine
Keywords
- Aging
- Cell behaviour
- EGF
- EGFR
- Signalling pathway
Eradicating tumor dormancy that develops following epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) treatment of EGFR-mutant non-small cell lung cancer, is an attractive therapeutic strategy but the mechanisms governing this process are poorly understood. Blockade of ERK1/2 reactivation following EGFR TKI treatment by combined EGFR/MEK inhibition uncovers cells that survive by entering a senescence-like dormant state characterized by high YAP/TEAD activity. YAP/TEAD engage the epithelial-to-mesenchymal transition transcription factor SLUG to directly repress pro-apoptotic BMF, limiting drug-induced apoptosis. Pharmacological co-inhibition of YAP and TEAD, or genetic deletion of YAP1, all deplete dormant cells by enhancing EGFR/MEK inhibition-induced apoptosis. Enhancing the initial efficacy of targeted therapies could ultimately lead to prolonged treatment responses in cancer patients.
MeSH Terms
- Adaptor Proteins, Signal Transducing
- Animals
- Apoptosis
- Cell Cycle Proteins
- Cell Line, Tumor
- Cell Proliferation
- Cell Survival
- Cellular Senescence
- Drug Resistance, Neoplasm
- ErbB Receptors
- Female
- Gene Deletion
- Gene Expression Regulation, Neoplastic
- Humans
- Lung Neoplasms
- MAP Kinase Kinase 1
- Male
- Mice
- Mice, Knockout
- Mutation
- Signal Transduction
- Transcription Factors
- Transcription, Genetic
Keywords
- YAP
- dormancy
- drug resistance
- drug tolerance
- epidermal growth factor receptor
- lung cancer
- senescence
Epidermal growth factor receptor (EGFR) mutation is the most frequently encountered oncogenic driver in lung cancer. Risk factors for EGFR mutation may help prevention, surveillance and diagnosis strategies of EGFR-mutated lung cancer. A nationwide, retrospective, longitudinal, cohort study was performed between January 2002 and December 2015. Patient data were collected from the Korean National Health Insurance Database. The lung cancer group included EGFR tyrosine kinase inhibitor (TKI)-treated patients. Controls were randomly selected from people without a history of lung cancer and determined to be four times the number of patients with EGFR-mutated advanced lung cancer. The risk model of developing EGFR-mutated lung cancer was constructed by multiple logistic regression analysis. Among the 2010 new cases of lung cancer treated in 2010-2015, 214 cases were classified as EGFR-mutated advanced lung cancer. The risk of developing EGFR-mutated advanced lung cancer was higher in patients in their 50s (odds ratio [OR]: 3.42; 95% confidence interval [CI]: 1.68-6.93), 60s (OR: 7.04; 95% CI: 3.35-14.77) and 70s (OR: 10.27; 95% CI: 4.73-22.30) and in those aged >80 years (OR: 5.98; 95% CI: 2.25-15.92) than those in their 40s. The risk of developing EGFR-mutated lung cancer was also higher in hospitalised patients with a history of pneumonia (OR: 5.22; 95% CI: 1.88-14.46) and those with gastroesophageal reflux disease (OR: 2.02; 95% CI: 1.32-3.07). Patients with EGFR-mutated advanced lung cancer were associated with ageing, history of being hospitalised for pneumonia and gastroesophageal reflux disease.
MeSH Terms
- Adult
- Aged
- Aged, 80 and over
- Aging
- Case-Control Studies
- ErbB Receptors
- Female
- Gastroesophageal Reflux
- Humans
- Lung Neoplasms
- Male
- Middle Aged
- Mutation
- Pneumonia
- Republic of Korea
- Retrospective Studies
- Risk Factors
- Young Adult
Keywords
- Ageing
- EGFR mutation
- GERD
- Lung cancer
- Pneumonia
- Risk factors
Aging is characterized by a progressive loss of physiological integrity, while cancer represents one of the primary pathological factors that severely threaten human lifespan and healthspan. In clinical oncology, drug resistance limits the efficacy of most anticancer treatments, and identification of major mechanisms remains a key to solve this challenging issue. Here, we highlight the multifaceted senescence-associated secretory phenotype (SASP), which comprises numerous soluble factors including amphiregulin (AREG). Production of AREG is triggered by DNA damage to stromal cells, which passively enter senescence in the tumor microenvironment (TME), a process that remarkably enhances cancer malignancy including acquired resistance mediated by EGFR. Furthermore, paracrine AREG induces programmed cell death 1 ligand (PD-L1) expression in recipient cancer cells and creates an immunosuppressive TME via immune checkpoint activation against cytotoxic lymphocytes. Targeting AREG not only minimized chemoresistance of cancer cells, but also restored immunocompetency when combined with classical chemotherapy in humanized animals. Our study underscores the potential of in vivo SASP in driving the TME-mediated drug resistance and shaping an immunosuppressive niche, and provides the proof of principle of targeting major SASP factors to improve therapeutic outcome in cancer medicine, the success of which can substantially reduce aging-related morbidity and mortality.
MeSH Terms
- Amphiregulin
- Animals
- Antineoplastic Agents
- B7-H1 Antigen
- Cells, Cultured
- Cellular Senescence
- Drug Resistance, Neoplasm
- Humans
- Mice
- Mice, Inbred NOD
- Mice, SCID
- Stromal Cells
- Tumor Microenvironment
Keywords
- aging
- amphiregulin
- cancer resistance
- clinical biomarker
- combinational treatment
- programmed cell death 1 ligand
- senescence-associated secretory phenotype
- stroma
Frailty is an age-associated condition, characterized by an inappropriate response to stress that results in a higher frequency of adverse outcomes (e.g., mortality, institutionalization and disability). Some light has been shed over its genetic background, but this is still a matter of debate. In the present study, we used network biology to analyze the interactome of frailty-related genes at different levels to relate them with pathways, clinical deficits and drugs with potential therapeutic implications. Significant pathways involved in frailty: apoptosis, proteolysis, muscle proliferation, and inflammation; genes as FN1, APP, CREBBP, EGFR playing a role as hubs and bottlenecks in the interactome network and epigenetic factors as HIST1H3 cluster and miR200 family were also involved. When connecting clinical deficits and genes, we identified five clusters that give insights into the biology of frailty: cancer, glucocorticoid receptor, TNF-α, myostatin, angiotensin converter enzyme, ApoE, interleukine-12 and -18. Finally, when performing network pharmacology analysis of the target nodes, some compounds were identified as potentially therapeutic (e.g., epigallocatechin gallate and antirheumatic agents); while some other substances appeared to be toxicants that may be involved in the development of this condition.
MeSH Terms
- Aging
- Apoptosis
- Cell Proliferation
- Epigenesis, Genetic
- Frailty
- Genes
- Humans
- Muscle, Smooth
- Pharmacology
- Proteolysis
- Signal Transduction
- Systems Biology
So far, there has been no effective cure for osteoporotic cortical bone, the most significant change in long bone structure during aging and the main cause of bone fragility fractures, because its underlying molecular and cellular mechanisms remain largely unknown. We used 3- and 15-mo-old mice as well as 15-mo-old mice treated with vehicle and gefitinib to evaluate structural, cellular, and molecular changes in cortical bone. We found that the senescence of osteoprogenitors was increased, whereas the expression of phosphorylated epidermal growth factor receptor (EGFR) on the endosteal surface of cortical bone down-regulated in middle-aged 15-mo-old mice compared with young 3-mo-old mice. Further decreasing EGFR signaling by gefitinib treatment in middle-aged mice resulted in promoted senescence of osteoprogenitors and accelerated cortical bone degeneration. Moreover, inhibiting EGFR signaling suppressed the expression of enhancer of zeste homolog 2 (Ezh2), the repressor of cell senescence-inducer genes, through ERK1/2 pathway, thereby promoting senescence in osteoprogenitors. Down-regulated EGFR signaling plays a physiologically significant role during aging by reducing Ezh2 expression, leading to the senescence of osteoprogenitors and the decline in bone formation on the endosteal surface of cortical bone.-Liu, G., Xie, Y., Su, J., Qin, H., Wu, H., Li, K., Yu, B., Zhang, X. The role of EGFR signaling in age-related osteoporosis in mouse cortical bone.
MeSH Terms
- Aging
- Animals
- Cellular Senescence
- Cortical Bone
- Down-Regulation
- Enhancer of Zeste Homolog 2 Protein
- ErbB Receptors
- Female
- MAP Kinase Signaling System
- Mice
- Mice, Inbred C57BL
- Osteoblasts
- Osteogenesis
- Osteoporosis
- Signal Transduction
Keywords
- ERK1/2
- Ezh2
- aging
- degeneration
- senescence
RhoB, a member of the Ras homolog gene family and GTPase, regulates intracellular signaling pathways by interfacing with epidermal growth factor receptor (EGFR), Ras, and phosphatidylinositol 3-kinase (PI3K)/Akt to modulate responses in cellular structure and function. Notably, the EGFR, Ras, and PI3K/Akt pathways can lead to downregulation of RhoB, while simultaneously being associated with an increased propensity for tumorigenesis. Functionally, RhoB, part of the Rho GTPase family, regulates intracellular signaling pathways by interfacing with EGFR, RAS, and PI3K/Akt/mammalian target of rapamycin (mTOR), and MYC pathways to modulate responses in cellular structure and function. Notably, the EGFR, Ras, and PI3K/Akt pathways can lead to downregulation of RhoB, while simultaneously being associated with an increased propensity for tumorigenesis. RHOB expression has a complex regulatory backdrop consisting of multiple histone deacetyltransferase (HDACs 1 and 6) and microRNA (miR-19a, -21, and -223)-mediated mechanisms of modifying expression. The interwoven nature of RhoB's regulatory impact and cellular roles in regulating intracellular vesicle trafficking, cell motion, and the cell cycle lays the foundation for analyzing the link between loss of RhoB and tumorigenesis within the context of age-related decline in RhoB. RhoB appears to play a tissue-specific role in tumorigenesis, as such, uncovering and appreciating the potential for restoration of RHOB expression as a mechanism for cancer prevention or therapeutics serves as a practical application. An in-depth assessment of RhoB will serve as a springboard for investigating and characterizing this key component of numerous intracellular messaging and regulatory pathways that may hold the connection between aging and tumorigenesis.
Keywords
- Aging
- Akt
- Cancer
- HDAC
- MicroRNA
- RhoB
Glioblastoma multiforme (GBM) is the most malignant central nervous system tumor. Alkylating agent, temozolomide (TMZ), is currently the first-line chemotherapeutic agent for GBM. However, the sensitivity of GBM cells to TMZ is affected by many factors. And, several clinic trials, including co-administration of TMZ with other drugs, have failed in successful treatment of GBM. We have previously reported that Netrin-4 (NTN4), a laminin-like axon guidance protein, plays a protective role in GBM cell senescence upon TMZ-triggered DNA damage. However, the master regulator of NTN4 needs further elucidation. Epidermal growth factor/Epidermal growth factor receptor (EGF/EGFR) can modulate the expression of various extracellular matrix related molecules, and prevent DNA damage in GBM cells. In this study, we investigated the relationship between EGF/EGFR signaling and NTN4, and explored their effect on therapeutic efficacy in GBM cells upon TMZ treatment. Co-expression analysis were performed by using the RNA sequencing data from NIH 934 cell lines and from single cell RNA sequencing data of GBM tumor. The co-expressing genes were used for GO enrichment and signaling pathway enrichment. mRNA expression of the target genes were quantified by qPCR, and cell senescence were investigated by Senescence-Associated Beta-Galactosidase Staining. Protein phosphorylation were observed and analyzed by immunoblotting. The RNA sequencing data and clinical information of TMZ treated patients were extracted from TCGA-glioblastoma project, and then used for Kaplan-Meier survival analysis. Analysis of RNA sequencing data revealed a potential co-expression relationship between NTN4 and EGFR. GO enrichment of EGFR-correlated genes indicated that EGFR regulates GBM cells in a manner similar to that in central nervous system development and neural cell differentiation. Pathway analysis suggested that EGFR and its related genes contribute to cell adhesion, extracellular matrix (ECM) organization and caspase related signaling. We also show that EGF stimulates NTN4 expression in GBM cells and cooperates with NTN4 to attenuate GBM cell senescence induced by DNA damage, possibly via AKT and ERK. Clinical analysis showed that co-expression of EGFR and NTN4 significantly predicts poor survival in TMZ-treated GBM patients. This study indicates that EGF/EGFR regulates and cooperates with NTN4 in DNA damage resistance in GBM. Therefore, our findings provide a potential therapeutic target for GBM.
MeSH Terms
- Brain Neoplasms
- Cell Line, Tumor
- Cellular Senescence
- DNA Damage
- Epidermal Growth Factor
- ErbB Receptors
- Glioblastoma
- Humans
- Netrins
- Up-Regulation
Keywords
- Cell senescence
- Epidermal growth factor
- Glioblastoma
- Netrin-4
Glioblastoma multiforme (GBM), the most prevalent brain tumor in adults, has extremely poor prognosis. Frequent genetic alterations that activate epidermal growth factor receptor (EGFR) and phosphatidylinositol-3 kinase (PI3K) signaling, as well as metabolic remodeling, have been associated with gliomagenesis. To establish a whole-animal approach that can be used to readily identify individual pathometabolic signaling factors, we induced glioma formation in the adult Drosophila brain by activating the EGFR-PI3K pathway. Glioma-induced animals showed significantly enlarged brain volume, early locomotor abnormalities, memory deficits, and a shorter lifespan. Combining bioinformatics analysis and glial-specific gene knockdown in the adult fly glioma model, we identified four evolutionarily conserved metabolic genes, including ALDOA, ACAT1, ELOVL6, and LOX, that were involved in gliomagenesis. Silencing of ACAT1, which controls cholesterol homeostasis, reduced brain enlargement and increased the lifespan of the glioma-bearing flies. In GBM patients, ACAT1 is overexpressed and correlates with poor survival outcomes. Moreover, pharmacological inhibition of ACAT1 in human glioma cell lines revealed that it is essential for tumor proliferation. Collectively, these results imply that ACAT1 is a potential therapeutic target, and cholesterol homeostasis is strongly related to glioma formation. This in vivo model provides several rapid and robust phenotypic readouts, allowing determination of the pathometabolic pathways involved in gliomagenesis, as well as providing valuable information for novel therapeutic strategies.
MeSH Terms
- Aging
- Animals
- Behavior, Animal
- Brain Neoplasms
- Carcinogenesis
- Cell Line, Tumor
- Cell Survival
- Disease Models, Animal
- Drosophila melanogaster
- Gene Expression Regulation, Neoplastic
- Glioma
- Humans
- Longevity
- Memory Disorders
- Metabolic Networks and Pathways
- Motor Activity
- Sterol O-Acyltransferase
- Survival Analysis
Keywords
- ACAT1
- Drosophila
- Glioma
- Metabolism
Although the signaling function of Na/K-ATPase has been studied for decades, the chasm between the pumping function and the signaling function of Na/K-ATPase is still an open issue. This article explores the relationship between ion pumping and signaling with attention to the amplification of oxidants through this signaling function. We specifically consider the Na/K-ATPase with respect to its signaling function as a superposition of different states described for its pumping function. We then examine how alterations in the relative amounts of these states could alter signaling through the Src-EGFR-ROS pathway. Using assumptions based on some experimental observations published by our laboratories and others, we develop some predictions regarding cellular oxidant stress.
MeSH Terms
- Aging
- ErbB Receptors
- Humans
- Ion Pumps
- MAP Kinase Signaling System
- Markov Chains
- Models, Theoretical
- Ouabain
- Oxidative Stress
- Reactive Oxygen Species
- Signal Transduction
- Sodium-Potassium-Exchanging ATPase
- src-Family Kinases
Keywords
- Markov chain
- Na/K-ATPase
- Src
- aging
- master equation
- oxidant stress
- reactive oxygen species
Pemetrexed (PEM) improves the overall survival of patients with advanced non-small cell lung cancer (NSCLC) when administered as maintenance therapy. However, PEM resistance often appears during the therapy. Although thymidylate synthase is known to be responsible for PEM resistance, no other mechanisms have been investigated in detail. In this study, we explored new drug resistance mechanisms of PEM-treated NSCLC using two combinations of parental and PEM-resistant NSCLC cell lines from PC-9 and A549. PEM increased the apoptosis cells in parental PC-9 and the senescent cells in parental A549. However, such changes were not observed in the respective PEM-resistant cell lines. Quantitative RT-PCR analysis revealed that, besides an increased gene expression of thymidylate synthase in PEM-resistant PC-9 cells, the [i]solute carrier family 19 member1[/i] ([i]SLC19A1)[/i] gene expression was markedly decreased in PEM-resistant A549 cells. The siRNA-mediated knockdown of SLC19A1 endowed the parental cell lines with PEM resistance. Conversely, PEM-resistant PC-9 cells carrying an [i]epidermal growth factor receptor (EGFR)[/i] mutation acquired resistance to a tyrosine kinase inhibitor erlotinib. Although erlotinib can inhibit the phosphorylation of EGFR and Erk, it is unable to suppress the phosphorylation of Akt in PEM-resistant PC-9 cells. Additionally, PEM-resistant PC-9 cells were less sensitive to the PI3K inhibitor LY294002 than parental PC-9 cells. These results indicate that SLC19A1 negatively regulates PEM resistance in NSCLC, and that EGFR-tyrosine-kinase-inhibitor resistance was acquired with PEM resistance through Akt activation in NSCLC harboring EGFR mutations.
Keywords
- EGFR-TKI
- NSCLC
- drug resistance
- drug-induced senescence
- pemetrexed
The conserved EGFR pathway is linked with multiple cancers in humans including breast, ovarian, and lung carcinoma. Withanolide A, one of the major withanolidal active compounds isolated from the Withania somnifera, extends lifespan and ameliorates stress resistance in wild-type C. elegans by targeting the Insulin/IGF-1 signaling pathway. Up-regulation of IGF1 can transactivate EGFR which inturn reduces longevity and promotes tumor development in an organism. We examined the effects of Withanolide A on the lifespan of a human EGFR-driven C. elegans transgenic model exhibiting the multivulva (Muv) phenotype. The results showed that WA extends the lifespan of both wild human EGFR-driven C. elegans model (human wild-type tyrosine kinase) as well as models bearing single (L858R), and double mutations (T790M-L858R). The lifespan extension observed in these transgenic strains was 20.35, 24.21 and 21.27%, respectively. Moreover, the reduced fat levels were noticed in both wild-type N2 worms and transgenic strains. These observations support the heathspan promoting effect of WA as lipid-rich diet has been reported to promote tumor development. In view of the fact that most of the well known FDA approved drugs such as gefitinib fail to inhibit the EGFR-associated cancers because of these mutations, the present findings show the potential of Withanolide A as a foreseen future nutraceutical to improve the average survival of cancer patients.
MeSH Terms
- Adipose Tissue
- Animals
- Caenorhabditis elegans
- ErbB Receptors
- Longevity
- Neoplasms
- Oxidative Stress
- Phytotherapy
- Plant Extracts
- Up-Regulation
- Withania
- Withanolides
Keywords
- C. elegans
- EGFR
- Fat deposition
- Lifespan
- Tumor
- Withanolide A
The mineralocorticoid receptor (MR) belongs to the steroid hormone receptor family and classically functions as a ligand-dependent transcription factor. It is involved in water-electrolyte homeostasis and blood pressure regulation but independent from these effects also furthers inflammation, fibrosis, hypertrophy and remodeling in cardiovascular tissues. Next to genomic effects, aldosterone elicits very rapid actions within minutes that do not require transcription or translation and that occur not only in classical MR epithelial target organs like kidney and colon but also in nonepithelial tissues like heart, vasculature and adipose tissue. Most of these effects can be mediated by classical MR and its crosstalk with different signaling cascades. Near the plasma membrane, the MR seems to be associated with caveolin and striatin as well as with receptor tyrosine kinases like EGFR, PDGFR and IGF1R and G protein-coupled receptors like AT1 and GPER1, which then mediate nongenomic aldosterone effects. GPER1 has also been named a putative novel MR. There is a close interaction and functional synergism between the genomic and the nongenomic signaling so that nongenomic signaling can lead to long-term effects and support genomic actions. Therefore, understanding nongenomic aldosterone/MR effects is of potential relevance for modulating genomic aldosterone effects and may provide additional targets for intervention.
MeSH Terms
- Aldosterone
- Animals
- Gene Expression Regulation
- Genomics
- Humans
- Receptors, Mineralocorticoid
- Signal Transduction
Keywords
- aging
- cardiovascular
- corticosteroids
- growth factor receptors
- renin–angiotensin system
The AD etiology is yet not properly known. Interactions among environmental factors, multiple susceptibility genes and aging, contribute to AD. This study investigates the factors that play role in causing AD and how changes in cellular pathways contribute to AD. PUBMED database, MEDLINE database and Google Scholar were searched with no date restrictions for published articles involving cellular pathways with roles in cancers, cell survival, growth, proliferation, development, aging, and also contributing to Alzheimer's disease. This research explores inverse relationship between AD and cancer, also investigates other factors behind AD using several already published research literature to find the etiology of AD. Cancer and Alzheimer's disease have inverse relationship in many aspects such as P53, estrogen, neurotrophins and growth factors, growth and proliferation, cAMP, EGFR, Bcl-2, apoptosis pathways, IGF-1, HSV, TDP-43, APOE variants, notch signals and presenilins, NCAM, TNF alpha, PI3K/AKT/MTOR pathway, telomerase, ROS, ACE levels. AD occurs when brain neurons have weakened growth, cell survival responses, maintenance mechanisms, weakened anti-stress responses such as Vimentin, Carbonic anhydrases, HSPs, SAPK. In cancer, these responses are upregulated and maintained. Evolutionarily conserved responses and maintenance mechanisms such as FOXO are impaired in AD. Countermeasures or compensatory mechanisms by AD affected neurons such as Tau, Beta Amyloid, S100, are last attempts for survival which may be protective for certain time, or can speed up AD in Alzheimer's microenvironment via C-ABL activation, GSK3, neuro-inflammation. Alzheimer's disease and Cancer have inverse relationship; many factors that are upregulated in any cancer to sustain growth and survival are downregulated in Alzheimer's disease contributing to neuro-degeneration. When aged neurons or genetically susceptible neurons have weakened growth, cell survival and anti-stress responses, age related gene expression changes, altered regulation of cell death and maintenance mechanisms, they contribute to Alzheimer's disease. Countermeasures by AD neurons such as Beta Amyloid Plaques, NFTs, S100, are last attempts for survival and this provides neuroprotection for certain time and ultimately may become pathological and speed up AD. This study may contribute in developing new potential diagnostic tests, interventions and treatments.
MeSH Terms
- Alzheimer Disease
- Humans
- Neoplasms
Keywords
- Aging
- Alzheimer’s disease
- Cancer
- Neuro-degeneration
- Neurofibrillary tangles
- Senile plaques
This study quantified low-frequency [i]KRAS[/i] mutations in normal lung and lung adenocarcinomas, to understand their potential significance in the development of acquired resistance to EGFR-targeted therapies. Allele-specific Competitive Blocker-PCR was used to quantify [i]KRAS[/i] codon 12 GAT (G12D) and GTT (G12V) mutation in 19 normal lung and 21 lung adenocarcinoma samples. Lung adenocarcinomas had [i]KRAS[/i] codon 12 GAT and GTT geometric mean mutant fractions of 1.94 × 10 and 1.16 × 10 , respectively. For 76.2% of lung adenocarcinomas, the level of [i]KRAS[/i] mutation was greater than the upper 95% confidence interval of that in normal lung. [i]KRAS[/i] mutant tumor subpopulations, not detectable by DNA sequencing, may drive resistance to EGFR blockade in lung adenocarcinoma patients.
Keywords
- carcinogenesis
- epidermal growth factor receptor
- mutation
- mutation detection
- non-small-cell lung cancer
- oncogene
- oncogene-induced senescence
- personalized medicine
- polyclonal tumor origin
- targeted molecular therapy
Growth pathways play key roles in longevity. The present study tested single-nucleotide polymorphisms (SNPs) in the connective tissue growth factor gene (CTGF) and the epidermal growth factor receptor gene (EGFR) for association with longevity. Comparison of allele and genotype frequencies of 12 CTGF SNPs and 41 EGFR SNPs between 440 American men of Japanese ancestry aged ≥95 years and 374 men of average life span revealed association with longevity at the p < .05 level for 2 SNPs in CTGF and 7 in EGFR. Two in CTGF and two in EGFR remained significant after Bonferroni correction. The SNPs of both CTGF and EGFR were in a haplotype block in each respective gene. Haplotype analysis confirmed the suggestive association found by χ2 analysis. We noted an excess of heterozygotes among the longevity cases, consistent with heterozygote advantage in living to extreme old age. No associations of the most significant SNPs were observed in whites or Koreans. In conclusion, the present findings indicate that genetic variation in CTGF and EGFR may contribute to the attainment of extreme old age in Japanese. More research is needed to confirm that genetic variation in CTGF and EGFR contributes to the attainment of extreme old age across human populations.
MeSH Terms
- Aged, 80 and over
- Asian Continental Ancestry Group
- Connective Tissue Growth Factor
- ErbB Receptors
- European Continental Ancestry Group
- Genetic Variation
- Humans
- Longevity
- Male
- Polymorphism, Single Nucleotide
- United States
Keywords
- Case–control study
- Connective tissue growth factor
- Epidermal growth factor
- Longevity
- Molecular genetics
Secretory phospholipase A2 Group-IIA (sPLA2 -IIA) catalyzes the hydrolysis of the sn-2 position of glycerophospholipids to yield fatty acids and lysophospholipids. sPLA2 -IIA is deregulated in various cancers; however, its role in hair follicle stem cell (HFSC) regulation is obscure. Here we report a transgenic mice overexpressing sPLA2 -IIA (K14-sPLA2 -IIA) showed depletion of HFSC pool. This was accompanied with increased differentiation, loss of ortho-parakeratotic organization and enlargement of sebaceous gland, infundibulum and junctional zone. The colony forming efficiency of keratinocytes was significantly reduced. Microarray profiling of HFSCs revealed enhanced level of epithelial mitogens and transcription factors, c-Jun and FosB that may be involved in proliferation and differentiation. Moreover, K14-sPLA2 -IIA keratinocytes showed enhanced activation of EGFR and JNK1/2 that led to c-Jun activation, which co-related with enhanced differentiation. Further, depletion of stem cells in bulge is associated with high levels of chromatin silencing mark, H3K27me3 and low levels of an activator mark, H3K9ac suggestive of alteration in gene expression contributing toward stem cells differentiation. Our results, first time uncovered that overexpression of sPLA2 -IIA lead to depletion of HFSCs and differentiation associated with altered histone modification. Thus involvement of sPLA2 -IIA in stem cells regulation and disease pathogenesis suggest its prospective clinical implications. Stem Cells 2016;34:2407-2417.
MeSH Terms
- Aging
- Animals
- Cell Differentiation
- Cell Proliferation
- Enzyme Activation
- Epidermis
- ErbB Receptors
- Gene Expression Profiling
- Group II Phospholipases A2
- Hair Follicle
- Histones
- Homeostasis
- Hyperplasia
- JNK Mitogen-Activated Protein Kinases
- Keratinocytes
- Lysine
- Methylation
- Mice, Transgenic
- Parakeratosis
- Proto-Oncogene Proteins c-jun
- Sebaceous Glands
- Signal Transduction
- Stem Cells
Keywords
- Differentiation
- Epidermis
- Hair follicle stem cells
- Histone
- Jun
The mechanisms of skin aging have not been completely elucidated. Anecdotal data suggests that EGFR inhibition accelerates aging-like skin changes. The objective of the study was to evaluate the clinical characteristics and investigate the cellular and molecular mechanisms underlying skin changes associated with the use of EFGRIs. Patients during prolonged treatment with EGFRIs (>3 months) were analyzed for aging-like skin changes. Baseline EGFR expression was compared in young (<25 years old) vs. old (> 65 years old) skin. In addition, the regulation of extracellular matrix, senescence-associated genes, and cell cycle status was measured in primary human keratinocytes treated with erlotinib in vitro. There were progressive signs of skin aging, including xerosis cutis, atrophy, rhytide formation, and/or actinic purpura in 12 patients. Keratinocytes treated with erlotinib in vitro showed a significant down-modulation of hyaluronan synthases (HAS2 and HAS3), whereas senescence-associated genes (p21, p53, IL-6, maspin) were upregulated, along with a G1 cell cycle arrest and stronger SA β-Gal activity. There was significantly decreased baseline expression in EGFR density in aged skin, when compared to young controls. EGFR inhibition results in molecular alterations in keratinocytes that may contribute to the observed skin aging of patients treated with respective targeted agents.
MeSH Terms
- Aged
- Aged, 80 and over
- Aging
- ErbB Receptors
- Erlotinib Hydrochloride
- Female
- Humans
- Retrospective Studies
- Skin Aging
- Skin Diseases
Keywords
- Aging
- EGFR
- Erlotinib
- Senescence
- Targeted therapy
The aim of this study was to characterize and relate the prolactin (PR), epidermal growth factor receptor (EGFR), α-actin and vimentin immunoreactivity in the prostate of elderly rats subjected to steroid hormonal imbalance. Senile and young rats were divided into the young group (YNG), the senile group (SE), the castrated group (CAS), the estrogen-deficient group (ED), the castrated estrogen group (CASE), and the estrogen-deficient androgen group (EDTEST). PR and EGFR increased in the estrogen and androgen ablation groups. In addition, EGFR influenced the immunolocalization by changing it from the prostatic stroma to the epithelium in elderly rats. Hormone ablation in elderly rats, not only related to androgen but also estrogen, led to increased stromal EGFR immunolocalization. The α-actin pattern decreased in the groups with estrogenic imbalance. Moreover, vimentin increased in the senile and estrogen deficient group. To conclude, we can suggest that EGFR contributed towards the proliferative process in the prostate, by means however, of different mechanisms, considering the androgenic and estrogenic pathways. Also, our results indicated that prolactin could be activated not only in an androgen-independent pathway but also in an estrogen independent pathway. Finally, PR and vimentin immunolocalization increase, in the prostatic stroma in the group showing estrogenic ablation, could be one of the factors which contribute to the reactive stroma formation.
MeSH Terms
- Actins
- Aging
- Androgens
- Animals
- Epithelium
- ErbB Receptors
- Estrogens
- Humans
- Male
- Prolactin
- Prostate
- Rats
- Vimentin
Keywords
- Egfr
- Prolactin
- Prostate
- Rat
- Vimentin and α-actin
Mast syndrome, an autosomal recessive, progressive form of hereditary spastic paraplegia, is associated with mutations in SPG21 loci that encode maspardin protein. Although SPG21-/- mice exhibit lower limb dysfunction, the role of maspardin loss in mast syndrome is unclear. To test the hypothesis that loss of maspardin attenuates the growth and maturation of cortical neurons in SPG21-/- mice. In a randomized experimental design SPG21-/- mice demonstrated significantly less agility and coordination compared to wild-type mice in beam walk, ledge, and hind limb clasp tests for assessing neuronal dysfunction (p ≤ 0.05). The SPG21-/- mice exhibited symptoms of mast syndrome at 6 months which worsened in 12-month-old cohort, suggesting progressive dysfunction of motor neurons. Ex vivo, wild-type cortical neurons formed synapses, ganglia and aggregates at 96 h, whereas SPG21-/- neurons exhibited attenuated growth with markedly less axonal branches. Additionally, epidermal growth factor markedly promoted the growth and maturation of SPG21 / cortical neurons but not SPG21-/- neurons. Consequently, quantitative RT-PCR identified a significant reduction in the expression of a subset of EGF-EGFR signaling targets. Our current study uncovered a direct role for maspardin in normal and EGF-induced growth and maturation of primary cortical neurons. The loss of maspardin resulted in attenuated growth, axonal branching, and attenuation of EGF signaling. Reinstating the functions of maspardin may reverse hind limb impairment associated with neuronal dysfunction in mast syndrome patients.
MeSH Terms
- Adaptor Proteins, Signal Transducing
- Aging
- Animals
- Cell Proliferation
- Cells, Cultured
- Cerebral Cortex
- Cohort Studies
- Dementia
- Disease Models, Animal
- Epidermal Growth Factor
- ErbB Receptors
- Mice, Knockout
- Motor Activity
- Neurons
- Random Allocation
- Spastic Paraplegia, Hereditary
- Synapses
Primary osteoporosis is a progressive bone disease that is characterized by a decrease in bone mass and density which can lead to an increased risk of fracture. Most of present treatments are effective for osteoporosis, but have limitations and side-effects. With the aging of the world population is increasing, the incidence of osteoporosis is rising. Therefore, the purpose of this study was to identify new candidate genes used as the therapeutic targets of primary osteoporosis. In this study, microarray data GSE35958 were downloaded from Gene Expression Omnibus, then the differentially expressed genes (DEGs) were identified by limma package. Gene Ontology (GO) and KEGG pathway enrichment analyses were performed for both up- and down-regulated DEGs using DAVID. In addition, the transcription factor analysis was conducted for DEGs. The protein-protein interaction (PPI) network was constructed by STRING and Cytoscape. Finally, CFinder was used to analyze the PPI sub-network. Totally, 327 up-regulated DEGs and 396 down-regulated DEGs were identified. The DEGs such as EGFR and AKT1 were mainly enriched in the pathway of focal adhesion. EGFR was also involved in cell adhesion based on GO enrichment analysis. Functional analysis of DEGs indicated that 26 transcription factors were screened. Moreover, EGFR, AKT1 and transcription factor CTNNB1 were the key nodes with high degrees according to PPI network and sub-network. The literature suggested that AKT1, EGFR and CTNNB1 were closely related to osteoblastic differentiation and osteoclastogenesis. Some crucial DEGs such as EGFR, AKT1 and CTNNB1 might be connected with primary osteoporosis and could be used as therapeutic targets of osteoporosis.
MeSH Terms
- Aging
- Down-Regulation
- Gene Expression
- Gene Expression Profiling
- Humans
- Osteoporosis
- Protein Interaction Maps
- Transcription Factors
- Up-Regulation
- beta Catenin
In glioblastoma (GBM), the gene for epidermal growth factor receptor (EGFR) is frequently amplified. EGFR mutations also are common, including a truncation mutation that yields a constitutively active variant called EGFR variant (v)III. EGFRvIII-positive GBM progresses rapidly; however, the reason for this is not clear because the activity of EGFRvIII is attenuated compared with EGF-ligated wild-type EGFR. We hypothesized that EGFRvIII-expressing GBM cells selectively express other oncogenic receptors that support tumor progression. Mining of The Cancer Genome Atlas prompted us to test whether GBM cells in culture, which express EGFRvIII, selectively express vascular endothelial growth factor receptor (VEGFR)2. We also studied human GBM propagated as xenografts. We then applied multiple approaches to test the effects of VEGFR2 on GBM cell growth, apoptosis, and cellular senescence. In human GBM, EGFR overexpression and EGFRvIII positivity were associated with increased VEGFR2 expression. In GBM cells in culture, EGFRvIII-initiated cell signaling increased expression of VEGFR2, which prevented cellular senescence and promoted cell cycle progression. The VEGFR-selective tyrosine kinase inhibitor cediranib decreased tumor DNA synthesis, increased staining for senescence-associated β-galactosidase, reduced retinoblastoma phosphorylation, and increased p27(Kip1), all markers of cellular senescence. Similar results were obtained when VEGFR2 was silenced. VEGFR2 expression by GBM cells supports cell cycle progression and prevents cellular senescence. Coexpression of VEGFR2 by GBM cells in which EGFR signaling is activated may contribute to the aggressive nature of these cells.
MeSH Terms
- Animals
- Brain Neoplasms
- Cell Proliferation
- Cellular Senescence
- ErbB Receptors
- Gene Knockdown Techniques
- Glioblastoma
- Heterografts
- Humans
- Immunoblotting
- Immunohistochemistry
- Mice
- Oligonucleotide Array Sequence Analysis
- Real-Time Polymerase Chain Reaction
- Signal Transduction
- Vascular Endothelial Growth Factor Receptor-2
Keywords
- EGF receptor
- EGFRvIII
- VEGF receptor-2
- cellular senescence
- glioblastoma
Circulating endothelial progenitor cells (EPCs) have multiple protective effects that facilitate repair of damage to tissues and organs. However, while various stressors are known to impair EPC function, the mechanisms of oxidative stress-induced EPC senescence remains unknown. We demonstrated that B2 receptor (B2R) expression on circulating CD34( ) cells was significantly reduced in patients with diabetes mellitus (DM) as compared to healthy controls. Furthermore, CD34( ) cell B2R expression in patients with DM was inversely correlated with plasma myeloperoxidase concentrations. Bradykinin (BK) treatment decreased human EPC (hEPC) senescence and intracellular oxygen radical production, resulting in reduced retinoblastoma 1 (RB) RNA expression in H2O2-induced senescent hEPCs and a reversal of the B2R downregulation that is normally observed in senescent cells. Furthermore, BK treatment of H2O2-exposed cells leads to elevated phosphorylation of RB, AKT, and cyclin D1 compared with H2O2-treatment alone. Antagonists of B2R, PI3K, and EGFR signaling pathways and B2R siRNA blocked BK protective effects. In summary, this study demonstrates that BK significantly inhibits oxidative stress-induced hEPC senescence though B2R-mediated activation of PI3K and EGFR signaling pathways.
MeSH Terms
- Antigens, CD34
- Antioxidants
- Bradykinin
- Bradykinin B2 Receptor Antagonists
- Case-Control Studies
- Cells, Cultured
- Cellular Senescence
- Cytoprotection
- Diabetes Mellitus
- Endothelial Progenitor Cells
- ErbB Receptors
- Humans
- Oxidants
- Oxidative Stress
- Protein Kinase Inhibitors
- Proto-Oncogene Proteins c-akt
- RNA Interference
- Receptor, Bradykinin B2
- Retinoblastoma Protein
- Signal Transduction
- Transfection
Keywords
- B2 receptor
- Gerotarget
- bradykinin
- endothelial progenitor cells
- senescence
The efficacy of gefitinib [an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor] in elderly patients with non-small cell lung cancer (NSCLC) and EGFR mutation has not been elucidated. Therefore, the objective of this study was to investigate the efficacy and feasibility of gefitinib in elderly chemotherapy-naive patients with NSCLC harboring sensitive EGFR mutations. We retrospectively evaluated the clinical effects of gefitinib as a first-line treatment for elderly (≥75 years) NSCLC patients with EGFR mutations (exon 19 deletion or exon 21 L858R mutation). All patients were initially treated with gefitinib (250 mg/day) at seven institutions. Between January 2006 and December 2012, 62 patients (17 men, 45 women) with a median age of 80 years (range, 75-89 years) were included in our analysis. The overall response and disease control rates were 61.2 and 83.8 %, respectively, and the median progression-free survival and overall survival were 13.2 and 19.0 months, respectively. Common adverse events included rash, diarrhea, and liver dysfunction. Major grade 3 or 4 toxicities included skin rash (3.2 %) and increased levels of aspartate aminotransferase or alanine aminotransferase (21.0 %). Gefitinib treatment was discontinued owing to adverse events of liver dysfunction in 3 patients, drug-induced pneumonitis in 2, and diarrhea in 1. First-line gefitinib could be a preferable standard treatment in elderly patients with advanced NSCLC harboring sensitive EGFR mutations.
MeSH Terms
- Aged
- Aged, 80 and over
- Aging
- Antineoplastic Agents
- Carcinoma, Non-Small-Cell Lung
- Drug Eruptions
- Drug Monitoring
- ErbB Receptors
- Feasibility Studies
- Female
- Follow-Up Studies
- Gefitinib
- Humans
- Incidence
- Japan
- Lung Neoplasms
- Male
- Mutation
- Protein Kinase Inhibitors
- Quinazolines
- Retrospective Studies
- Severity of Illness Index
- Survival Analysis
Keywords
- Advanced non-small cell lung cancer
- EGFR mutations
- Elderly patients
- First-line chemotherapy
- Gefitinib
- Non-small cell lung cancer
Age-related changes in long-lived tissue-resident stem cells may be tightly linked to aging and age-related diseases such as cancer. Centrosomes play key roles in cell proliferation, differentiation and migration. Supernumerary centrosomes are known to be an early event in tumorigenesis and senescence. However, the age-related changes of centrosome duplication in tissue-resident stem cells in vivo remain unknown. Here, using anti-γ-tubulin and anti-PH3, we analyzed mitotic intestinal stem cells with supernumerary centrosomes in the adult Drosophila midgut, which may be a versatile model system for stem cell biology. The results showed increased centrosome amplification in intestinal stem cells of aged and oxidatively stressed Drosophila midguts. Increased centrosome amplification was detected by overexpression of PVR, EGFR, and AKT in intestinal stem cells/enteroblasts, known to mimic age-related changes including hyperproliferation of intestinal stem cells and hyperplasia in the midgut. Our data show the first direct evidence for the age-related increase of centrosome amplification in intestinal stem cells and suggest that the Drosophila midgut is an excellent model for studying molecular mechanisms underlying centrosome amplification in aging adult stem cells in vivo.
MeSH Terms
- Animals
- Cellular Senescence
- Centrosome
- Drosophila
- Drosophila Proteins
- ErbB Receptors
- Intestines
- Mitosis
- Oxidative Stress
- Proto-Oncogene Proteins c-akt
- Receptor Protein-Tyrosine Kinases
- Receptors, Invertebrate Peptide
- Stem Cells
Keywords
- Adult stem cell
- Aging
- Centrosome
- Drosophila midgut
- EGFR
- PVR
Neurosphere formation is commonly used as a surrogate for neural stem cell (NSC) function but the relationship between neurosphere-initiating cells (NICs) and NSCs remains unclear. We prospectively identified, and isolated by flow cytometry, adult mouse lateral ventricle subventricular zone (SVZ) NICs as Glast(mid)EGFR(high)PlexinB2(high)CD24(-/low)O4/PSA-NCAM(-/low)Ter119/CD45(-) (GEPCOT) cells. They were highly mitotic and short-lived in vivo based on fate-mapping with Ascl1(CreERT2) and Dlx1(CreERT2). In contrast, pre-GEPCOT cells were quiescent, expressed higher Glast, and lower EGFR and PlexinB2. Pre-GEPCOT cells could not form neurospheres but expressed the stem cell markers Slc1a3-CreER(T), GFAP-CreER(T2), Sox2(CreERT2), and Gli1(CreERT2) and were long-lived in vivo. While GEPCOT NICs were ablated by temozolomide, pre-GEPCOT cells survived and repopulated the SVZ. Conditional deletion of the Bmi-1 polycomb protein depleted pre-GEPCOT and GEPCOT cells, though pre-GEPCOT cells were more dependent upon Bmi-1 for Cdkn2a (p16(Ink4a)) repression. Our data distinguish quiescent NSCs from NICs and make it possible to study their properties in vivo.DOI: http://dx.doi.org/10.7554/eLife.02669.001.
MeSH Terms
- Aging
- Animals
- Antimitotic Agents
- Cell Proliferation
- Cell Separation
- Dacarbazine
- Glial Fibrillary Acidic Protein
- Integrases
- Mice, Inbred C57BL
- Neural Stem Cells
- Neurogenesis
- Neuroglia
- Phenotype
- Polycomb Repressive Complex 1
- Prosencephalon
- Proto-Oncogene Proteins
- Spheroids, Cellular
- Temozolomide
Keywords
- Bmi-1
- fate-mapping
- forebrain
- prospective identification
- stem cell
To assess the association between thiamin concentration, frusemide use, and renal function in older adults. Thiamin concentration was measured in 73 consecutive admissions of patients aged over 65 years in a secondary care hospital. The patients were assigned to the study or control group based on frusemide use. A two-sample t test estimated the association between frusemide use and thiamin concentration and regression between thiamin concentration and EGFR. The mean (SD) thiamin concentration was 181.7 (64.6) nmol/L in those using frusemide and 169.3 (46.8) in non-users, P =0.35. There was a weak linear relationship between thiamin concentration and EGFR, with thiamin concentration being 17.0 nmol/L lower per 30 ml/min greater EGFR, P=0.076. Thiamin concentration was below the reference range in 20/73 (27.4%) of the participants. We found no association between frusemide use and thiamin concentration, but showed a significant prevalence of lower thiamin concentration in the study population of older adults.
MeSH Terms
- Aged
- Aged, 80 and over
- Aging
- Diuretics
- Female
- Furosemide
- Glomerular Filtration Rate
- Heart Failure
- Humans
- Kidney
- Male
- New Zealand
- Nutritional Status
- Prevalence
- Secondary Care Centers
- Thiamine
- Thiamine Deficiency
Elastin is a long-lived protein and a key component of connective tissues. The tissular elastin content decreases during chronological aging, and the mechanisms underlying its slow repair are not known. Lipid oxidation products that accumulate in aged tissues may generate protein dysfunction. We hypothesized that 4-hydroxynonenal (4-HNE), a highly reactive α,β-aldehydic product generated from polyunsaturated fatty acid peroxidation, could contribute to inhibiting elastin repair by antagonizing the elastogenic signaling of transforming growth factor-β1 (TGF-β1) in skin fibroblasts. We report that a low 4-HNE concentration (2µmol/L) inhibits the upregulation of tropoelastin expression stimulated by TGF-β1 in human and murine fibroblasts. The study of signaling pathways potentially involved in the regulation of elastin expression showed that 4-HNE did not block the phosphorylation of Smad3, an early step of TGF-β1 signaling, but inhibited the nuclear translocation of Smad2. Concomitantly, 4-HNE modified and stimulated the phosphorylation of the epidermal growth factor receptor (EGFR) and subsequently ERK1/2 activation, leading to the phosphorylation/stabilization of the Smad transcriptional corepressor TGIF, which antagonizes TGF-β1 signaling. Inhibitors of EGFR (AG1478) and MEK/ERK (PD98059), and EGFR-specific siRNAs, reversed the inhibitory effect of 4-HNE on TGF-β1-induced nuclear translocation of Smad2 and tropoelastin synthesis. In vivo studies on aortas from aged C57BL/6 mice showed that EGFR is modified by 4-HNE, in correlation with an increased 4-HNE-adduct accumulation and decreased elastin content. Altogether, these data suggest that 4-HNE inhibits the elastogenic activity of TGF-β1, by modifying and activating the EGFR/ERK/TGIF pathway, which may contribute to altering elastin repair in chronological aging and oxidative stress-associated aging processes.
MeSH Terms
- Adult
- Aging
- Aldehydes
- Animals
- Aorta
- Cell Line, Transformed
- Elastin
- ErbB Receptors
- Fibroblasts
- Flavonoids
- Gene Expression Regulation
- Homeodomain Proteins
- Humans
- Lipid Peroxidation
- Mice
- Mitogen-Activated Protein Kinase 1
- Mitogen-Activated Protein Kinase 3
- Primary Cell Culture
- Protein Transport
- Quinazolines
- Repressor Proteins
- Signal Transduction
- Smad2 Protein
- Smad3 Protein
- Transforming Growth Factor beta1
- Tyrphostins
Keywords
- 4-Hydroxynonenal
- Aging
- EGF receptor
- Fibroblasts
- Free radicals
- TGF-β1
- Tropoelastin
Interleukin 6 (IL-6) signaling plays a role in inflammation, cancer, and senescence. Here, we identified soluble IL-6 receptor (sIL-6R) as a member of the senescence-associated secretory phenotype (SASP). Senescence-associated sIL-6R upregulation was mediated by mammalian target of rapamycin (mTOR). sIL-6R was mainly generated by a disintegrin and metalloprotease 10 (ADAM10)-dependent ectodomain shedding to enable IL-6 trans-signaling. In vivo, heterozygous PTEN-knockout mice exhibited higher mTOR activity and increased sIL-6R levels. Moreover, aberrant EGF receptor (EGFR) activation triggered IL-6 synthesis. In analogy to senescence, EGFR-induced activation of mTOR also induced IL-6R expression and sIL-6R generation. Hence, mTOR activation reprograms IL-6 non-responder cells into IL-6 responder cells. Our data suggest that mTOR serves as a central molecular switch to facilitate cellular IL-6 classic and trans-signaling via IL-6R upregulation with direct implications for cellular senescence and tumor development.
MeSH Terms
- ADAM Proteins
- ADAM10 Protein
- Amyloid Precursor Protein Secretases
- Animals
- Carrier Proteins
- Cell Line
- Cell Transformation, Neoplastic
- Cellular Senescence
- ErbB Receptors
- Fetal Proteins
- Gene Expression Regulation, Neoplastic
- Humans
- Interleukin-6
- Membrane Proteins
- Mice
- Mice, Knockout
- Microtubule-Associated Proteins
- PTEN Phosphohydrolase
- RNA, Small Interfering
- Receptors, Interleukin-6
- Signal Transduction
- TOR Serine-Threonine Kinases
Keywords
- EGFR
- Interleukin 6
- Interleukin 6-Receptor
- SASP
- mTOR
- senescence
In previous work, we constructed short hairpin RNA (shRNA) expression plasmids that targeted human EGF and IGF-1 receptors messenger RNA, respectively, and demonstrated that these vectors could induce apoptosis of human nasopharyngeal cell lines (CNE2) and inhibit ligand-induced pAkt and pErk activation. We have constructed multiple shRNA expression vectors of targeting EGFR, IGF1R and Bcl-xl, which were transfected to the CNE2 cells. The mRNA expression was assessed by RT-PCR. The growth of the cells, cell cycle progression, apoptosis of the cells, senescent tumor cells and the proteins of EGFR, IGF1R and Bcl-xl were analyzed by MTT, flow cytometry, cytochemical therapy or Western blot. In group of simultaneously blocking EGFR, IGF1R and Bcl-xl genes, the mRNA of EGFR, IGF1R and Bcl-xl expression was decreased by (66.66±3.42)%, (73.97±2.83)% and (64.79±2.83)%, and the protein expressions was diminished to (67.69±4.02)%, (74.32±2.30)%, and (60.00±3.34)%, respectively. Meanwhile, the cell apoptosis increased by 65.32±0.18%, 65.16±0.25% and 55.47±0.45%, and senescent cells increased by 1.42±0.15%, 2.26±0.15% and 3.22±0.15% in the second, third and fourth day cultures, respectively. Simultaneously blocking EGFR, IGF1R and Bcl-xl genes is capable of altering the balance between proliferating versus apoptotic and senescent cells in the favor of both of apoptosis and senescence and, therefore, the tumor cells regression.
MeSH Terms
- Apoptosis
- Cell Line, Tumor
- Cell Proliferation
- Cellular Senescence
- ErbB Receptors
- Humans
- Nasopharyngeal Neoplasms
- RNA Interference
- Receptor, IGF Type 1
- bcl-X Protein
Keywords
- Bcl-xl
- Epidermal growth factor receptor
- Insulin-like growth factor-1 receptor
- Nasopharyngeal cancer
- Senescence
- Short hairpin RNA
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that causes progressive paralysis due to motor neuron death. Several lines of published evidence suggested that inhibition of epidermal growth factor receptor (EGFR) signaling might protect neurons from degeneration. To test this hypothesis in vivo, we treated the SOD1 transgenic mouse model of ALS with erlotinib, an EGFR inhibitor clinically approved for oncology indications. Although erlotinib failed to extend ALS mouse survival it did provide a modest but significant delay in the onset of multiple behavioral measures of disease progression. However, given the lack of protection of motor neuron synapses and the lack of survival extension, the small benefits observed after erlotinib treatment appear purely symptomatic, with no modification of disease course.
MeSH Terms
- Amyotrophic Lateral Sclerosis
- Animals
- Astrocytes
- Biomarkers
- Disease Models, Animal
- Disease Progression
- ErbB Receptors
- Erlotinib Hydrochloride
- Humans
- Longevity
- Mice
- Mice, Transgenic
- Microglia
- Motor Neurons
- Neuromuscular Junction
- Phosphorylation
- Protein Kinase Inhibitors
- Quinazolines
- Spinal Cord
- Staining and Labeling
- Superoxide Dismutase
- Superoxide Dismutase-1
- Survival Analysis
- Synapses
- Time Factors
Maintenance therapy with gefitinib notably improves survival in patients with advanced non-small cell lung cancer (NSCLC) and EGFR mutation-positive tumors, but the economic impact of this practice is unclear. A decision-analytic model was developed to simulate 21-day patient transitions in a 10-year time horizon. The clinical data were primarily obtained from the results of a pivotal phase III trial that assessed gefitinib maintenance treatment in patients with advanced NSCLC. The cost data were derived from the perspective of the Chinese health care system. The primary outcome was the incremental cost-effectiveness ratio (ICER) at a willingness-to-pay (WTP) threshold of 3 times the per capita GDP of China. Sensitivity analyses were used to explore the impact of uncertainty regarding the results. The impact of the gefitinib patient assistance program (GPAP) was evaluated. After EGFR genotyping, gefitinib maintenance treatment for advanced NSCLC with EGFR mutations increased the life expectancy by 0.74 years and 0.46 QALYs compared with routine follow-up at an additional cost of $26,149.90 USD ($7,178.20 with the GPAP). The ICER for gefitinib maintenance was $57,066.40 and $15,664.80 per QALY gained (at a 3% discount rate) without and with the GPAP, respectively. The utility of progression free survival, the hazard ratio of progression-free survival for gefitinib treatment and the cost of gefitinib per dose were the three factors that had the greatest influence on the results. These results indicate that gene-guided maintenance therapy with gefitinib with the GPAP might be a cost-effective treatment option.
MeSH Terms
- Antineoplastic Agents
- Carcinoma, Non-Small-Cell Lung
- China
- Clinical Trials, Phase III as Topic
- Cost-Benefit Analysis
- Decision Support Techniques
- Disease-Free Survival
- Drug Costs
- ErbB Receptors
- Gefitinib
- Humans
- Life Expectancy
- Lung Neoplasms
- Markov Chains
- Medical Assistance
- Models, Economic
- Mutation
- Precision Medicine
- Protein Kinase Inhibitors
- Quality-Adjusted Life Years
- Quinazolines
- Survival Analysis
- Time Factors
- Treatment Outcome
- Uncertainty
We performed a treatment efficacy analysis for non-small cell lung cancer (NSCLC) patients' population with EGFR mutation aimed at optimization of pharmacoeconomic factors. The employment of gefitinib leads to an increase in patients' life expectancy for a median of 1.05 years. The average cost-effectiveness of this therapy is 934.8 thousand rubles per additional year (903.9-1100.5 thousand rubles for each year). If gefitinib therapy is given only to patients with proved EGFR mutation it can decrease the average expenses by 211.6-251.8 thousand rubles per patient in comparison to undiagnosed patients's population receiving gefitinib without a decrease in clinical effect. Comparison of selective gefitinib administration with isolated chemotherapy (CT) yields an incremental cost-effectiveness ratio of 960.7 to 1010.0 thousand rubles per additional year. Therefore, the strategy of EGFR gene mutations testing in patients with inoperable NSCLC with consequent gefitinib therapy administration in patients positive for mutation lead to an increase in life expectancy and is characterized by acceptable cost-effectiveness.
MeSH Terms
- Adult
- Aged
- Aged, 80 and over
- Antineoplastic Agents
- Biomarkers, Tumor
- Carcinoma, Non-Small-Cell Lung
- Cost-Benefit Analysis
- ErbB Receptors
- Female
- Gefitinib
- Humans
- Life Expectancy
- Lung Neoplasms
- Male
- Middle Aged
- Mutation
- Quinazolines
- Russia
- Survival Analysis
- Treatment Outcome
The Cbl family proteins function as both E3 ubiquitin ligases and adaptor proteins to regulate various cellular signaling events, including the insulin/insulin-like growth factor 1 (IGF1) and epidermal growth factor (EGF) pathways. These pathways play essential roles in growth, development, metabolism, and survival. Here we show that in Drosophila melanogaster, Drosophila Cbl (dCbl) regulates longevity and carbohydrate metabolism through downregulating the production of Drosophila insulin-like peptides (dILPs) in the brain. We found that dCbl was highly expressed in the brain and knockdown of the expression of dCbl specifically in neurons by RNA interference increased sensitivity to oxidative stress or starvation, decreased carbohydrate levels, and shortened life span. Insulin-producing neuron-specific knockdown of dCbl resulted in similar phenotypes. dCbl deficiency in either the brain or insulin-producing cells upregulated the expression of dilp genes, resulting in elevated activation of the dILP pathway, including phosphorylation of Drosophila Akt and Drosophila extracellular signal-regulated kinase (dERK). Genetic interaction analyses revealed that blocking Drosophila epidermal growth factor receptor (dEGFR)-dERK signaling in pan-neurons or insulin-producing cells by overexpressing a dominant-negative form of dEGFR abolished the effect of dCbl deficiency on the upregulation of dilp genes. Furthermore, knockdown of c-Cbl in INS-1 cells, a rat β-cell line, also increased insulin biosynthesis and glucose-stimulated secretion in an ERK-dependent manner. Collectively, these results suggest that neuronal dCbl regulates life span, stress responses, and metabolism by suppressing dILP production and the EGFR-ERK pathway mediates the dCbl action. Cbl suppression of insulin biosynthesis is evolutionarily conserved, raising the possibility that Cbl may similarly exert its physiological actions through regulating insulin production in β cells.
MeSH Terms
- Animals
- Brain
- Carbohydrate Metabolism
- Cell Line
- Down-Regulation
- Drosophila Proteins
- Drosophila melanogaster
- ErbB Receptors
- Extracellular Signal-Regulated MAP Kinases
- Female
- Insulin
- Insulin-Secreting Cells
- Intercellular Signaling Peptides and Proteins
- Longevity
- Male
- Neurons
- Oxidative Stress
- Proto-Oncogene Proteins c-cbl
- RNA Interference
- RNA, Small Interfering
- Rats
- Signal Transduction
- Starvation
The main aim of this work is to investigate the expression of factors related to senescence and cell death pathways in non-small cell lung cancers (NSCLCs) and colorectal cancers (CRCs) in relation to telomere status. We analyzed 158 tissue samples, 36 NSCLCs, 43 CRCs, and their corresponding control tissues obtained from patients submitted to surgery. Telomere function was evaluated by determining telomerase activity and telomere length. Expression of factors related to senescence, cell death pathways, transformation and tumorigenesis was investigated using arrays. Results were validated by real-time quantitative PCR. Considering tumors with telomere shortening, expression for BNIP3, DAPK1, NDRG1, EGFR, and [[CDKN2A]] was significantly higher in NSCLC than in CRC, whereas TP53 was overexpressed in CRC with respect to NSCLC. Moreover, compared to nontumor samples, DAPK1, GADD45A, SHC1, and TP53 were downregulated in the group of NSCLCs with telomere shortening, and no significant differences were found in CRC. In NSCLC, the failure of pathways which involve factors such as DAPK1, GADD45A, SHC1, and TP53, in response to short telomeres, could promote tumor progression. In CRC, the viability of these pathways in response to short telomeres could contribute to limiting tumorigenesis.
MeSH Terms
- Adenocarcinoma
- Aged
- Aging
- Biomarkers, Tumor
- Carcinoma, Large Cell
- Carcinoma, Non-Small-Cell Lung
- Carcinoma, Squamous Cell
- Cell Death
- Colon
- Colorectal Neoplasms
- Female
- Gene Expression Profiling
- Humans
- Lung
- Lung Neoplasms
- Male
- Oligonucleotide Array Sequence Analysis
- Prognosis
- Rectum
- Telomerase
- Telomere
- Telomere Shortening
Stem cells are tightly regulated by both intrinsic and extrinsic signals as well as the extracellular matrix (ECM) for tissue homeostasis and regenerative capacity. Matrix metalloproteinases (MMPs), proteolytic enzymes, modulate the turnover of numerous substrates, including cytokine precursors, growth factors, and ECM molecules. However, the roles of MMPs in the regulation of adult stem cells are poorly understood. In the present study, we utilize the Drosophila midgut, which is an excellent model system for studying stem cell biology, to show that Mmp1 is involved in the regulation of intestinal stem cells (ISCs). The results showed that Mmp1 is expressed in the adult midgut and that its expression increases with age and with exposure to oxidative stress. Mmp1 knockdown or Timp-overexpressing flies and flies heterozygous for a viable, hypomorphic Mmp1 allele increased ISC proliferation in the gut, as shown by staining with an anti-phospho-histone H3 antibody and BrdU incorporation assays. Reduced Mmp1 levels induced intestinal hyperplasia, and the Mmp1depletion-induced ISC proliferation was rescued by the suppression of the EGFR signaling pathway, suggesting that Mmp1 regulates ISC proliferation through the EGFR signaling pathway. Furthermore, adult gut-specific knockdown and whole-animal heterozygotes of Mmp1 increased additively sensitivity to paraquat-induced oxidative stress and shortened lifespan. Our data suggest that Drosophila Mmp1 is involved in the regulation of ISC proliferation for maintenance of gut homeostasis.
MeSH Terms
- Animals
- Cell Proliferation
- Drosophila melanogaster
- Enterocytes
- ErbB Receptors
- Gene Knockdown Techniques
- Homeostasis
- Hyperplasia
- Intestines
- Life Expectancy
- Matrix Metalloproteinase 1
- Mitotic Index
- Oxidative Stress
- RNA Interference
- Stem Cell Niche
- Stem Cells
One of the most consistent pathological conditions in the gastrointestinal tract with advancing age is malignancy, particularly gastrointestinal cancers, the incidence of which increases sharply with aging. Although the reasons for the age-related rise in colorectal cancer are not fully understood, we hypothesize that aging increases susceptibility of the colon to carcinogen(s)/toxicant(s), leading to an increase in cancer stem-like cells (CSLCs) that express cancer stem cell markers, in the colonic mucosa. The current study demonstrates that aging is associated with increased expression of several colon CSLC markers [CD44, CD166, and aldehyde dehydrogenase 1 (ALDH-1)] and a higher proportion of cells expressing these markers. Aging is also accompanied by increased expression of miR-21 in colon. These increases are further increased in response to the colonic carcinogen dimethylhydrazine (DMH). Aging is also associated with increased tyrosine-phosphorylated epidermal growth factor receptor (EGFR). Inhibition of EGFR using the EGFR inhibitor cetuximab abrogated the age-related increase in CD166 and ALDH-1 as well as miRNA (miR)-21. Our results provide new evidence that aging and DMH are associated with increases in CSLC biomarkers and miR21, each of which have been linked to colorectal cancer. EGFR inhibition attenuates these changes, indicating a role for EGFR in age- and mutagen-associated changes in CSLCs.
MeSH Terms
- Aging
- Animals
- Antibodies, Monoclonal
- Antibodies, Monoclonal, Humanized
- Antineoplastic Agents
- Biomarkers, Tumor
- Carcinogens
- Cetuximab
- Colon
- Colonic Neoplasms
- Dimethylhydrazines
- ErbB Receptors
- Gene Expression Regulation, Neoplastic
- Intestinal Mucosa
- Male
- MicroRNAs
- Neoplastic Stem Cells
- Rats
To evaluate age-related differences in histopathologic and molecular profile of glioblastomas (GBMs) at various age groups, with special reference to TP53 mutation, epidermal growth factor receptor (EGFR) amplification, EGFR vIII mutant, PTEN deletion, and IDH1 mutation. Agewise GBM incidence was calculated over a period of 5 years (2005 to 2009). Seventy-five GBMs were selected for molecular analysis. Majority of cases were in the age group of 41 to 60 years, and mean age was 43.6 years. Histology of all 75 cases selected for molecular profiling was identical. Primary adult GBMs showed EGFR amplification and PTEN deletion in majority (37.3% and 54.9%, respectively). TP53 and IDH1 mutations were rare (11.8% cases each). In secondary GBMs, TP53 (66.7%) and IDH1 mutations (44.4%) were most frequent. PTEN deletion was seen in 33.3% and none had EGFR amplification. Pediatric GBMs (<18 y) harbored frequent TP53 mutations (46.7%) and PTEN deletion in 40%. IDH1 mutations and EGFR amplification were absent. The molecular profile of primary GBMs in young adults (19 to 40 y) was distinctly different from that of adults older than 40 years. TP53 mutation was present in 20% cases. The frequency of EGFR amplification (13.3%) and PTEN deletion (33.3%) was significantly low (P=0.028 and 0.046, respectively). IDH1 mutation, which is rare in primary adult GBMs, was present in 40% of cases. Molecular heterogeneity exists within GBMs of different age cohorts. The molecular profile of GBMs in young adults is distinctly different. Thus, there is a strong need for further studies in various age groups to provide guidelines for therapeutic targeting.
MeSH Terms
- Adolescent
- Adult
- Aging
- Brain Neoplasms
- Child
- Chromosome Aberrations
- ErbB Receptors
- Female
- Gene Amplification
- Gene Expression Profiling
- Genetic Variation
- Glioblastoma
- Humans
- Isocitrate Dehydrogenase
- Male
- Middle Aged
- Mutation
- PTEN Phosphohydrolase
- Sequence Deletion
- Tumor Suppressor Protein p53
- Young Adult
The mineralocorticoid receptor (MR) is a steroid receptor that physiologically regulates water and electrolyte homeostasis but that can also induce pathophysiological effects in the renocardiovascular system. Classically, the MR acts as a transcription factor at glucocorticoid response elements but additional protein-protein interactions with other signaling cascades have been described. Of these, the crosstalk with EGFR signaling is especially interesting because various vasoactive substances like angiotensin II and endothelin-1 also mediate their pathophysiological effects via the EGFR. Recently, the MR has been shown to interact nongenomically (via transactivation) and genomically with the epidermal growth factor receptor (via altered expression). These interactions seem to contribute to physiological (e.g. salt homeostasis) as well as pathophysiological (e.g. vascular function) MR effects. The current knowledge on the mechanisms of interaction and on the possible cellular and systemic physiological as well as pathophysiological relevance is reviewed in this article.
MeSH Terms
- Aging
- Animals
- Blood Vessels
- Cell Proliferation
- ErbB Receptors
- Humans
- Inflammation
- Models, Biological
- Protein Binding
- Receptor Cross-Talk
- Receptors, Mineralocorticoid
- Signal Transduction
In North Africa, nasopharyngeal carcinoma (NPC) is characterized by a bimodal distribution involving a juvenile (≤ 30 years old) and an elder population (> 30 years old). The Epstein Barr virus oncogene LMP1, the anti-apoptotic Bcl-2 protein and the tumor suppressor p53 have recently emerged as biomarkers of the disease. EGFR/ErbB1 expression is detected in the majority of NPC tumors with advanced disease. To obtain greater insight into the potential oncogenic mechanisms specific to these two NPC populations, we examined the correlation between EGFR expression and patient age, and determined the molecular profiles of its associations with the biomarkers of NPC. We performed an immunohistochemical analysis of the latter molecules in NPC specimens from eleven Algerian patients (six patients ≤ 30 years of age and five patients > 30 years of age) using the LSAB method. Evaluation of the biopsies, based on the intensity of staining and the percentage of positive cells, showed that LMP1 expression was higher in patients under 30 years of age. Conversely, EGFR, like Bcl-2 and p53, was significantly up-regulated in tumors from elderly patients. Analysis of all tumors showed that EGFR expression was constantly (100%) associated with high p53 nuclear accumulation and Bcl-2 expression in LMP1-positive tissues. Biopsies negative for Bcl-2 staining were found to display low amounts of p53 (100%), and to be constantly negative for EGFR (100%). Molecular classification of all NPC tissues showed that the majority of patients displaying a EGFR /LMP1 /Bcl-2 /p53-high molecular pattern were in the older age group. On the other hand, the most of the EGFR negative results were associated with the juvenile form of the disease and were characterized by an important diversity of molecular patterns. Our preliminary results suggest that in Algerian patients, the bimodal distribution of NPC might be related to distinct expression profiles of viral and cellular biomarkers of NPC.
MeSH Terms
- Adolescent
- Adult
- Africa, Northern
- Aging
- Biomarkers, Tumor
- Biopsy
- Carcinoma
- Cell Nucleus
- Cohort Studies
- ErbB Receptors
- Female
- Humans
- Immunohistochemistry
- Male
- Middle Aged
- Nasopharyngeal Carcinoma
- Nasopharyngeal Neoplasms
- Proto-Oncogene Proteins c-bcl-2
- Tumor Suppressor Protein p53
- Viral Matrix Proteins
- Young Adult
The aim of this study was a cytogenetic analysis of stallions semen to find sex chromosome aberrations and to determine if there was an association between stallion's age and aberration frequency for the sex chromosomes. Sperm samples were collected from 22 stallions of various age from 3 to 23 years. Multicolour FISH was performed on each sample, using probes for the sex chromosomes and EGFR gene, localized on 4p12 in domestic horse. A total of 26199 sperm cells were analysed (from 1 070 to 1 532 per animal). Among the analysed cells, there were 50.318% with X chromosome, 48.543% with Y chromosome and 1.139% with aberrant chromosomes. The frequency of aberrations was: sex chromosomes nullisomy (0.466%), XY aneuploidy (0.454%), XX disomy (0.146%), YY disomy (0.041%), diploidy (0.024%) and trisomy XXY (0.008%). Additionally there was a correlation between the age of an animal and the frequency of sex chromosome aberration and a significant positive correlation between age and disomy of XY, XX, YY, trisomy of XXY, autosomal disomy was seen. A Correlation between the age of a stallion and the level of nullisomy was negative. The present study demonstrated that FISH technique is a powerful method to identify sex chromosome aberrations in equine spermatozoa and might be very helpful for a breeder during a selection for the best stallion.
MeSH Terms
- Aging
- Animals
- Horses
- Male
- Semen Analysis
- Sex Chromosome Aberrations
Neural progenitor cells (NPCs) in the adult subventricular zone (SVZ) are associated with ependymal and vasculature niches, which regulate stem cell self-renewal and differentiation. Activated Type B stem cells and their progeny, the transit-amplifying type C cells, which express EGFR, are most highly associated with vascular cells, indicating that this niche supports lineage progression. Here, we show that proliferative SVZ progenitor cells home to endothelial cells in a stromal-derived factor 1 (SDF1)- and CXC chemokine receptor 4 (CXCR4)-dependent manner. We show that SDF1 strongly upregulates EGFR and alpha6 integrin in activated type B and type C cells, enhancing their activated state and their ability to bind laminin in the vascular niche. SDF1 increases the motility of type A neuroblasts, which migrate from the SVZ toward the olfactory bulb. Thus, differential responses to SDF1 can regulate progenitor cell occupancy of and exit from the adult SVZ vascular niche.
MeSH Terms
- Aging
- Animals
- B-Lymphocytes
- Blood Vessels
- Cell Lineage
- Cerebral Ventricles
- Chemokine CXCL12
- Chemotaxis
- Endothelial Cells
- ErbB Receptors
- Integrins
- Lymphocyte Activation
- Mice
- Models, Biological
- Neurons
- Receptors, CXCR4
- Signal Transduction
- Stem Cell Transplantation
- Stem Cells
Skin hair follicles (HF) contain bulge stem cells (SC) that regenerate HFs during hair cycles, and repair skin epithelia following injury. As natural aging is associated with decreased skin repair capacity in humans, we have investigated the impact of age on human scalp HF bulge cell number and function. Here, we isolated human bulge cells, characterized as CD200 /KRT15 /KRT19 cells of the HF, by dissection-combined CD200 selection in young and aged human skin. Targeted transcriptional profiling indicates that KRT15, KRT19, Dkk3, Dkk4, Tcf3, S100A4, Gas1, EGFR and CTGF/CCN2 are also preferentially expressed by human bulge cells, compared to differentiated HF keratinocytes (KC). Our results demonstrate that aging does not alter expression or localization of these HF SC markers. In addition, we could not detect significant differences in HF density or bulge cell number between young and aged human scalp skin. Interestingly, hedgehog (Hh) signaling is activated in human bulge cells in vivo, and down-regulated in differentiated HF KCs, both in young and aged skin. In addition, activation of Hh signaling by lentivirus-mediated overexpression of transcription factor Gli1 induces transcription of HF SC markers KRT15, KRT19, and Gas1, in cultured KCs. Together with previously reported knock-out mouse results, these data suggest a role for Hh signaling in maintaining bulge cell phenotype in young and aged human skin.
MeSH Terms
- Adult
- Aged
- Aging
- Antigens, CD
- Cell Cycle Proteins
- Cell Separation
- GPI-Linked Proteins
- Hair Follicle
- Hedgehog Proteins
- Humans
- Keratin-15
- Keratinocytes
- Membrane Proteins
- Stem Cells
Glioblastoma multiforme remains one of the most intractable human malignancies. Glioblastomas arise due to activation of multiple oncogenic pathways leading to increased cellular growth, proliferation and tumor cell survival. siRNA induced RNA Interference (RNAi) responses result in the degradation of specific mRNA species. In theory, RNAi responses can selectively target intersecting oncogenic pathways to induce a tumor cell specific RNAi synthetic lethal response. However, the concept of inducing in vivo synthetic lethal RNAi responses has not yet been addressed. Here we tested the in vivo ability of synthetic lethal RNAi responses to treat glioblastoma. To deliver siRNAs into cells, we fused a peptide transduction delivery domain to a dsRNA-binding domain (PTD-DRBD). DRBDs avidly bind to siRNAs, masking the siRNA anionic negative charge and allowing for efficient PTD-mediated siRNA delivery into the entire cell population. Combinatorial targeting of EGF-Receptor (EGFR) and Akt2, but not Ak1 or Akt3, by PTD-DRBD delivered siRNAs synergized to induce tumor cell specific apoptosis. In vivo PTD-DRBD delivery of EGFR and Akt2 siRNAs induced tumor specific apoptosis and significantly increased survival in intracerebral glioblastoma mouse models (p < 0.0005), whereas delivery of irrelevant control siRNAs did not alter longevity. Thus, siRNA induced synthetic lethal RNAi responses have great potential for personalized medicine treatment of cancer.
MeSH Terms
- Animals
- Apoptosis
- Brain Neoplasms
- ErbB Receptors
- Genes, Lethal
- Glioblastoma
- Humans
- Immunoblotting
- In Situ Nick-End Labeling
- Longevity
- Mice
- Mice, Nude
- Protein Structure, Tertiary
- Proto-Oncogene Proteins c-akt
- RNA, Double-Stranded
- RNA, Small Interfering
- Survival Rate
- Tumor Cells, Cultured
- Xenograft Model Antitumor Assays
Aging is associated with increased incidence of colon cancers. It is also becoming evident that cancer stem cells (CSC) play a vital role in the pathogenesis and prognosis of colon cancer. Recently, we reported the presence of colon cancer stem-like cells in macroscopically normal mucosa in patients with adenomatous polyps and that they increase with aging, suggesting that aging may predispose the colon to carcinogenesis. In the current study we have examined the combined effects of aging and carcinogen exposure on the status of colon CSCs in an experimental model. We used young (4-6 months) and aged (22-24 months) rats and exposed them to the carcinogen, dimethylhydroxide (DMH). We investigated the expression of colon cancer stem cell markers, CD44, CD166, EpCam, and ALDH1 as well as EGFR expression in normal colonic crypt epithelium following carcinogen treatment. Our results demonstrate that aging per se or carcinogen treatment alone causes an increase in the number of colon cancer stems cells, as evidenced by increased immunoreactive-CSC-markers positive cells in the colonic mucosa. In aged rats, carcinogen exposure results in a more pronounced increase in colon cancer stem cells. Our study shows that in aging colon the effects of carcinogens are more pronounced, and an increase in colon CSCs is one of the earliest changes preceding tumor development. Moreover, the current investigation of the use of a panel of immunohistochemical markers of colon CSC can potentially serve as a prognostic marker during screening for colon cancer.
MeSH Terms
- Aging
- Animals
- Carcinogens
- Cell Transformation, Neoplastic
- Colon
- Dimethylhydrazines
- Male
- Neoplastic Stem Cells
- Rats
- Rats, Inbred F344
The objective of the present studies was to determine the localization of epidermal growth factor (EGF) and the epidermal growth factor receptor (EGFR) in testicular tissue collected from male alpacas at 12 and 24 months of age. In the testes of 12-month-old alpacas, positive staining for EGF was not detected. EGFR was localized to Leydig cells within the 12-month-old alpaca testis, but staining was absent within seminiferous tubules. At 24 months of age, EGF was localized to Leydig cells, peritubular myoid cells, Sertoli cells and germ cells of the alpaca testis, with a preferential adluminal compartment staining within the seminiferous tubules. EGFR was also localized to the Leydig cells, peritubular myoid cells, Sertoli cells and germ cells within the 24-month-old alpaca testis, but staining within the tubules was primarily within the basal compartment. Results indicate distinct temporal and spatial regulation of EGF and EGFR in the alpaca testis and support a potential role for EGF and its related ligands in alpaca testis development and spermatogenesis.
MeSH Terms
- Aging
- Animals
- Camelids, New World
- Epidermal Growth Factor
- ErbB Receptors
- Leydig Cells
- Male
- Mice
- Mice, Knockout
- Reproduction
- Species Specificity
- Swine
- Testis
Elderly and poor performance status advanced non-small cell lung cancer (NSCLC) patients often tolerate chemotherapy poorly. Special approaches are needed for these patient populations. Tyrosine kinase inhibitors (TKIs) of the epidermal growth factor receptor (EGFR), erlotinib and gefitinib, are active agents in the treatment of advanced NSCLC. Several phase II trials have been conducted utilizing EGFR TKIs in elderly or poor performance status patients with advanced NSCLC. This review will summarize the results of erlotinib or gefitinib in these subsets of patients with advanced NSCLC.
MeSH Terms
- Age Factors
- Aging
- Antineoplastic Combined Chemotherapy Protocols
- Carcinoma, Non-Small-Cell Lung
- Clinical Trials as Topic
- Disease Progression
- ErbB Receptors
- Erlotinib Hydrochloride
- Gefitinib
- Humans
- Lung Neoplasms
- Neoplasm Staging
- Protein-Tyrosine Kinases
- Quinazolines
- Treatment Outcome
Signaling through the epidermal growth factor receptor (EGFR) by ligands such as epidermal growth factor (EGF), transforming growth factor alpha (TGFA), and amphiregulin (AREG) has been reported to have effects on skeletal growth. The role of betacellulin (BTC), another EGFR ligand, in skeletal development and bone metabolism is unknown. In previous experiments, transgenic mice overexpressing BTC ubiquitously under the control of the chicken beta-actin promoter (BTC-tg) exhibited stunted growth and disproportionately sized long bones. In this study, we performed a detailed phenotypic analysis of BTC-tg mice at 3, 6, and 9 wk of age. Osteoblastic cells from transgenic mice showed strong expression of BTC as determined by Western blots and by immunohistochemistry on bone sections. In femurs of male and female BTC-tg mice, we found reduced longitudinal bone growth and a pronounced increase in total volumetric BMD. The increased femoral BMD was mainly caused by augmented endocortical bone apposition and subsequent cortical bone thickening. In contrast, vertebral BMD was reduced in BTC-tg mice of both sexes. An overall similar phenotype was found in 6-mo-old BTC-tg mice. The increase in cortical bone mass in the appendicular skeleton of BTC-tg mice was largely blocked when they were crossed into the Egfr (Wa5) background characterized by a dominant negative EGFR. Our study showed that overexpression of BTC results in an EGFR-dependent upregulation of cortical bone mass in the appendicular skeleton of mice, uncovering a potential novel anabolic pathway for cortical bone.
MeSH Terms
- Aging
- Animals
- Betacellulin
- Biomarkers
- Bone Density
- Bone and Bones
- Chickens
- ErbB Receptors
- Femur
- Intercellular Signaling Peptides and Proteins
- Ligands
- Mice
- Mice, Transgenic
- Organ Size
- Osteoblasts
- Phenotype
- Spine
- Transgenes
It is becoming increasingly evident that cancer stem cells play a vital role in development and progression of cancers and relapse following chemotherapy. The present study examines the presence of cancer stem-like cells (CSC) in adenomatous polyps and in normal appearing colonic mucosa in humans during aging. The number of polyps was found to increase linearly with advancing age (r(2)=0.92, p<0.02). Immunohistochemical analysis revealed co-localization of CSC markers CD44 and CD166 in colonic polyps. Real-time RT-PCR analysis of normal appearing mucosa from subjects with adenomatous polyps showed an age-related rise in CSC as evidenced by the increased expression of CD44, CD166 and ESA. A similar phenomenon was also observed for EGFR. In addition, the expression each CSC marker was found to be about 2-fold higher in subjects with 3-4 polyps than those with 1-2 polyps. In conclusion, our results show that colon cancer stem-like cells are present in the premalignant adenomatous polyps as well in normal appearing colonic mucosa. Moreover, our observation of the age-related rise in CSC in macroscopically normal colonic mucosa suggests a predisposition of the organ to developing colorectal cancer.
MeSH Terms
- Adenomatous Polyps
- Age Factors
- Aged
- Aged, 80 and over
- Aging
- Antigens, CD
- Cell Adhesion Molecules, Neuronal
- Colonic Neoplasms
- Fetal Proteins
- Humans
- Hyaluronan Receptors
- Incidence
- Intestinal Mucosa
- Neoplastic Stem Cells
- Risk Factors
- United States
Vertebrate pigment cells are derived from neural crest cells and are a useful system for studying neural crest-derived traits during post-embryonic development. In zebrafish, neural crest-derived melanophores differentiate during embryogenesis to produce stripes in the early larva. Dramatic changes to the pigment pattern occur subsequently during the larva-to-adult transformation, or metamorphosis. At this time, embryonic melanophores are replaced by newly differentiating metamorphic melanophores that form the adult stripes. Mutants with normal embryonic/early larval pigment patterns but defective adult patterns identify factors required uniquely to establish, maintain or recruit the latent precursors to metamorphic melanophores. We show that one such mutant, picasso, lacks most metamorphic melanophores and results from mutations in the ErbB gene erbb3b, which encodes an EGFR-like receptor tyrosine kinase. To identify critical periods for ErbB activities, we treated fish with pharmacological ErbB inhibitors and also knocked down erbb3b by morpholino injection. These analyses reveal an embryonic critical period for ErbB signaling in promoting later pigment pattern metamorphosis, despite the normal patterning of embryonic/early larval melanophores. We further demonstrate a peak requirement during neural crest migration that correlates with early defects in neural crest pathfinding and peripheral ganglion formation. Finally, we show that erbb3b activities are both autonomous and non-autonomous to the metamorphic melanophore lineage. These data identify a very early, embryonic, requirement for erbb3b in the development of much later metamorphic melanophores, and suggest complex modes by which ErbB signals promote adult pigment pattern development.
MeSH Terms
- Aging
- Alleles
- Animals
- Base Sequence
- Cell Lineage
- Cell Movement
- Embryo, Nonmammalian
- Gene Expression Regulation, Developmental
- Larva
- Melanophores
- Mutation
- Neural Crest
- Protein Kinase Inhibitors
- Receptor, ErbB-3
- Signal Transduction
- Skin Pigmentation
- Zebrafish
Human corneal endothelial cells (HCEC), particularly from older donors, only proliferate weakly in response to EGF. The protein tyrosine phosphatase, PTP1B, is known to negatively regulate EGF-induced signaling in several cell types by dephosphorylating the epidermal growth factor receptor (EGFR). The current studies were conducted to determine whether PTP1B plays a role in regulating cell cycle entry in HCEC in response to EGF stimulation. Donor corneas were obtained from the National Disease Research Interchange and accepted for study based on established exclusion criteria. PTP1B was localized in the endothelium of ex vivo corneas and in cultured cells by immunocytochemistry. Western blot analysis verified PTP1B protein expression in HCEC and then compared the relative expression of EGFR and PTP1B in HCEC from young (<3 years old) and older donors (>60 years old). The effect of inhibiting the activity of PTP1B on S-phase entry was tested by comparing time-dependent BrdU incorporation in subconfluent HCEC incubated in the presence or absence of the PTP1B inhibitor, CinnGEL 2Me, before EGF stimulation. PTP1B was localized in a punctate pattern mainly within the cytoplasm of HCEC in ex vivo corneas and cultured cells. Western blots revealed the presence of three PTP1B-positive bands in HCEC and the control. Further western blot analysis showed no significant age-related difference in expression of EGFR (p=0.444>0.05); however, PTP1B expression was significantly higher in HCEC from older donors (p=0.024<0.05). Pre-incubation of HCEC with the PTP1B inhibitor significantly increased (p=0.019<0.05) the number of BrdU positive cells by 48 h after EGF stimulation. Both immunolocalization and western blot studies confirmed that PTP1B is expressed in HCEC. Staining patterns strongly suggest that at least a subset of PTP1B is localized to the cytoplasm and most likely to the endoplasmic reticulum, the known site of EGFR/PTP1B interaction following EGF stimulation. PTP1B expression, but not EGFR expression, was elevated in HCEC from older donors, suggesting that the reduced proliferative activity of these cells in response to EGF is due, at least in part, to increased PTP1B activity. The fact that inhibition of PTP1B increased the relative number of cells entering S-phase strongly suggests that PTP1B helps negatively regulate EGF-stimulated cell cycle entry in HCEC. These results also suggest that it may be possible to increase the proliferative activity of HCEC, particularly in cells from older donors, by inhibiting the activity of this important protein tyrosine phosphatase.
MeSH Terms
- Adolescent
- Aged
- Aging
- Blotting, Western
- Bromodeoxyuridine
- Cells, Cultured
- Cornea
- Cytoplasm
- Endothelium, Corneal
- Epidermal Growth Factor
- ErbB Receptors
- Humans
- Immunohistochemistry
- In Vitro Techniques
- Middle Aged
- Protein Tyrosine Phosphatase, Non-Receptor Type 1
- S Phase
- Tissue Distribution
Identify molecular targets for development of tumor-specific pharmacotherapeutics aimed at treating vestibular schwannomas (VSs). Activated epidermal growth factor receptor B (ErbB) 2 and ErbB3 are abundantly expressed in VS. ErbB2 signaling is essential for Schwann cell differentiation, survival, and proliferation. VS arise after loss of functional merlin, a putative tumor suppressor. Merlin internalizes ErbB2 receptors in rodent Schwann cells. Unregulated ErbB signaling may contribute to VS tumorigenesis. Molecular analyses, retrospective clinical correlation. Tertiary referral center. Thirty-eight specimens from patients operated for sporadic (n=21) and neurofibromatosis (NF) 2-related (n=17) VS. VS analyses via real-time polymerase chain reaction, immunohistochemistry, and correlation with patient clinical data. ErbB signaling molecule expression, tumor size, age, and NF2 status. VS upregulated epidermal growth factor (EGF) receptor in 68% (62% sporadic and 75% NF2-associated VS) and ErbB2 in 84% (76% sporadic and 94% NF2-related VS). ErbB3 was upregulated in 34%, and ErbB4 is downregulated in NF2-related VS. Of EGF receptor (EGFR) ligands, EGF was upregulated in all NF2-related VS, but none of the sporadic VS (p<0.01), and transforming growth factor alpha and beta-cellulin showed upregulation in 67% of NF2-related VS but not sporadic VS (p=0.02 and p=0.01, respectively). Neuregulin (Nrg) was upregulated in 86% of sporadic VS versus 19% of NF2-related VS (p<0.01). EGFR expression levels correlated directly with VS tumor size and inversely with patient age, whereas Nrg expression correlated directly with age (p=0.0005). EGF expression predicts NF2 status, whereas Nrg predicts non-NF2 status (p<0.01). These findings implicate the ErbB pathway in VS growth and as potential molecular targets for VS pharmacotherapy.
MeSH Terms
- Adult
- Aged
- Aging
- Antineoplastic Agents
- DNA
- Enzyme-Linked Immunosorbent Assay
- Female
- Gene Expression Regulation
- Genes, erbB
- Humans
- Immunohistochemistry
- Ligands
- Male
- Middle Aged
- Neuregulins
- Neurofibromatosis 2
- Neuroma, Acoustic
- Peripheral Nervous System Neoplasms
- RNA
- RNA, Messenger
- Retrospective Studies
- Tissue Banks
- Up-Regulation
Aging relates to declined proliferative capacity of the liver, but the molecular mechanism is not well understood. We examined whether functional changes of epidermal growth factor (EGF) receptor (EGFR) are involved in age-related decline in EGF-induced DNA synthesis using hepatocytes isolated in periportal and perivenous regions of the liver, which differ in the proliferative capacity. Periportal hepatocytes (PPH) and perivenous hepatocytes (PVH) in 7-, 30-, and 90-week-old rats were isolated using the digitonin/collagenase perfusion technique. DNA synthesis was assessed by [methyl-(3)H]thymidine incorporation. EGFR binding affinity to EGF was analyzed by Scatchard analysis using [(125)I]EGF. EGFR dimerization and phosphorylation were determined by Western blot analysis. EGF-induced DNA synthesis was greater in PPH than in PVH from rats of 7 weeks, but the zonal difference disappeared with aging. [(125)I]EGF binding studies indicated that high-affinity EGFR in both subpopulations also disappeared with aging. Furthermore, EGF-induced dimerization in both subpopulations was down-regulated with aging, and the pattern of EGFR phosphorylation was parallel to that of dimerization. These data suggest that age-related decline in EGF-induced DNA synthesis of PPH and PVH is caused by down-regulation of EGFR dimerization through the decrease of high-affinity EGFR.
MeSH Terms
- Aging
- Animals
- Cell Proliferation
- Cell Separation
- Cells, Cultured
- DNA
- Dimerization
- Epidermal Growth Factor
- ErbB Receptors
- Hepatocytes
- Male
- Phosphorylation
- Rats
- Rats, Wistar
Although the regulatory mechanisms for the age-related rise in proliferation and reduction in apoptosis in the colonic mucosa are yet to be fully delineated, we have demonstrated that these events are associated with increased expression and activation of epithelial growth factor receptor (EGFR)/ErbB-1 and some of its receptor family members (EGFRs), indicating their involvement in these processes. However, the downstream signaling events of EGFR and/or its family members regulating age-related changes in mucosal proliferation and apoptosis remain to be delineated. Cell cycle and apoptosis regulatory protein-1 (CARP-1), a novel growth signaling regulator that we isolated, participates in EGFR-dependent signaling. In the current investigation, we examined the involvement of CARP-1 in colonic mucosal growth-related processes during aging. We report that the age-related reduction in apoptosis in the colonic mucosa is associated with increased expression and tyrosine phosphorylation of not only EGFR but also ErbB-2 and ErbB-3. In contrast, protein and mRNA levels of CARP-1 as well as tyrosine phosphorylation of CARP-1 are decreased. Additionally, we have observed that administration of wortmannin, an inhibitor of phosphatidylinositol 3-kinase activity that accelerates apoptosis in the colonic mucosa of aged rats, causes a marked increase in expression and tyrosine phosphorylation of CARP-1. The age-related decline in CARP-1 expression could partly be attributed to increased methylation of the CARP-1 promoter. Taken together, our data suggest that not only EGFR but also its other members are involved in regulating colonic mucosal growth during aging and that CARP-1 may play a crucial role in transducing EGFRs signals.
MeSH Terms
- Aging
- Animals
- Apoptosis
- Apoptosis Regulatory Proteins
- Cells, Cultured
- Colon
- Intestinal Mucosa
- Male
- Nuclear Proteins
- Rats
- Rats, Inbred F344
Dysbalanced production of inflammatory cytokines is involved in immunosenescence in aging. The age-related changes of the levels of circulating inflammatory mediators and their clinical importance have not been investigated until recently. Still, little is known about the influence of aging on circulating levels of many cytokines, chemokines, growth factors, and angiogenic factors. In the present study, we evaluated the effect of aging on 30 different serum biomarkers involved in pro- and anti-inflammatory responses using multianalyte LabMAP Luminex technology. The simultaneous measurement of serological markers has been done in 397 healthy subjects between 40 and 80 years old. We demonstrated an increase in serum interferon-gamma-inducible chemokines (MIG and IP-10), eotaxin, chemoattractant for eosinophils, and soluble TNFR-II with advancing age. Serum levels of EGFR and EGF, important regulators of cell growth and differentiation, were decreased with age in healthy donors. These data suggest novel pathways, which may be involved in age-associated immunosenescence.
MeSH Terms
- Adult
- Age Distribution
- Aged
- Aged, 80 and over
- Aging
- Biomarkers
- Chemokine CCL11
- Chemokine CXCL10
- Chemokine CXCL9
- Epidermal Growth Factor
- ErbB Receptors
- Female
- Humans
- Male
- Middle Aged
- Receptors, Tumor Necrosis Factor, Type II
- Reference Values
- Solubility
Three Popeye domain-containing (Popdc 1-3) family-members are known in vertebrates. Their exact function is as yet unknown although involvement in cell adhesion has been suggested. We report herein sequencing of the rat Popdc 1-3 cDNAs that show high homology to other vertebrate orthologs and are expressed primarily in the heart and skeletal muscles. Popdc2 splice variants were identified, with Popdc2C showing a distinctive age-dependent decline. In isolated cardiomyocytes, Popdc genes were negatively regulated by serum, an effect that was reversed by EGFR-kinase inhibition, suggesting an EGFR-dependent modulation of Popdc gene expression.
MeSH Terms
- Aging
- Animals
- Base Sequence
- Cell Adhesion
- Cells, Cultured
- Cloning, Molecular
- DNA, Complementary
- ErbB Receptors
- Gene Expression Regulation
- Membrane Proteins
- Molecular Sequence Data
- Multigene Family
- Muscle Proteins
- Myocardium
- Myocytes, Cardiac
- Organ Specificity
- Rats
- Signal Transduction
Neuregulins and their signaling ErbB receptors play a critical role during the development of the mammalian peripheral nervous system, including some kinds of mechanoreceptors such as the Pacinian corpuscles which become structurally and functionally mature postnatally. In this study, we investigated whether or not ErbBs in Pacinian corpuscles undergoes developmental changes, as well as if their expression depends on the innervation. Pacinian corpuscles from 7-day- and 3-month-old mice were assessed for the immunohistochemical detection of EGFR or ErbB1, ErbB2, ErbB3 and ErbB4. The effect of denervation on the expression of ErbBs in mature Pacinian corpuscles was also analyzed. Developing 7-day-old Pacinian corpuscles express ErbB2 and ErbB3 immunoreactivity in the inner-core (regarded as modified Schwann cells), whereas the mature 3-month-old Pacinian corpuscles exclusively displayed ErbB4 immunoreactivity in the outer core and the capsule (regarded as endoneurial and perineurial cells). Denervation was without effect on the ErbB expression. Present results demonstrate maturational related changes and cell segregation in the expression of ErbB receptors by murine Pacinian corpuscles, and that this expression is independent of the innervation.
MeSH Terms
- Aging
- Animals
- Animals, Newborn
- Apoptosis
- Denervation
- ErbB Receptors
- Forelimb
- Immunohistochemistry
- Mice
- Mice, Inbred C57BL
- Pacinian Corpuscles
- S100 Proteins
Environmental signals including epidermal growth factor family members, Shh, fibroblast growth factor, and bone morphogenetic protein (BMP) can affect multiple processes during the development of the central nervous system, raising questions about the mechanisms that determine how these pleiotropic signals are interpreted to elicit appropriate responses at specific times and locations. Here we address the idea that different thresholds of stimulation determine how progenitors in the dorsal telencephalon interpret these signals. One mechanism for achieving different thresholds of signaling is illustrated by the developmental increase in the level of epidermal growth factor receptor (EGFR) expression among a subset of progenitors in the late embryonic telencephalon. Another mechanism is illustrated by the antagonistic interaction of BMP with Shh, which can influence EGFR expression and neuron subtype choice. We focus on the similarities and differences in the control of these responses and address the possibility that the gamma-aminobutyric acidergic neuron specification might be linked to progenitor expression of a higher level of EGFRs.
MeSH Terms
- Adaptation, Physiological
- Aging
- Animals
- Cell Aggregation
- Cell Differentiation
- Cell Movement
- Differential Threshold
- Environment
- ErbB Receptors
- In Vitro Techniques
- Mice
- Nerve Net
- Neuronal Plasticity
- Neurons
- Organogenesis
- Rats
- Rats, Sprague-Dawley
- Signal Transduction
- Stem Cells
- Telencephalon
- Tissue Distribution
It is believed that there are two distinct pathological pathways leading to the development of human glioblastomas (GBM) in Caucasian populations. Primary (de novo) GBM most often occurs in older individuals, and is characterized by the overexpression/amplification of epidermal growth factor receptor gene (EGFR), whereas secondary GBM, which progresses from a low-grade astrocytoma, often affects younger individuals and frequently contains the TP53 mutation. We and others have previously found that the age of onset of GBM in Chinese patients tends to be younger than that in Caucasian patients. To identify whether GBMs from Chinese patients share this common pattern of genetic alterations, expression levels of EGFR and TP53 and TP53 mutation were analyzed in 56 randomly selected Chinese GBMs (30 primary and 26 secondary), including 47 adult-onset and 9 pediatric GBMs. Consistent with other studies, overexpression/mutation of TP53 and aneuploid DNA content were more frequently detected in secondary GBMs of Chinese adult patients. In contrast to that observed in Caucasian patients, no significant difference was observed in the age distribution and the frequency of EGFR overexpression/amplification between primary and secondary GBMs in adult Chinese patients. Furthermore, the overexpression of EGFR was much higher in late-onset (age >45 years) GBMs (73%) than that in both early-onset (age 18-45 years) (17%) and pediatric (age <18 years) GBMs (11%), suggesting that overexpression of EGFR in Chinese GBMs may be associated closely with the patients age but not with the tumors' pathological pathway.
MeSH Terms
- Adolescent
- Adult
- Aged
- Aging
- Asian Continental Ancestry Group
- Brain Neoplasms
- Child
- China
- DNA, Neoplasm
- ErbB Receptors
- European Continental Ancestry Group
- Female
- Gene Amplification
- Gene Expression Regulation, Neoplastic
- Genes, p53
- Glioblastoma
- Humans
- Immunohistochemistry
- Male
- Middle Aged
- Mutation
- Ploidies
- Tumor Suppressor Protein p53
Huntington's disease (HD) is a late onset heritable neurodegenerative disorder caused by expansion of a polyglutamine (polyQ) sequence in the protein huntingtin (Htt). Transgenic models in mice have suggested that the motor and cognitive deficits associated to this disease are triggered by extended neuronal and possibly glial dysfunction, whereas neuronal death occurs late and selectively. Here, we provide in vivo evidence that expanded polyQ peptides antagonize epidermal growth factor receptor (EGFR) signaling in Drosophila glia. We targeted the expression of the polyQ-containing domain of Htt or an extended polyQ peptide alone in a subset of Drosophila glial cells, where the only fly glutamate transporter, dEAAT1, is detected. This resulted in formation of nuclear inclusions, progressive decrease in dEAAT1 transcription and shortened adult lifespan, but no significant glial cell death. We observed that brain expression of dEAAT1 is normally sustained by the EGFR-Ras-extracellular signal-regulated kinase (ERK) signaling pathway, suggesting that polyQ could act by antagonizing this pathway. We found that the presence of polyQ peptides indeed abolished dEAAT1 upregulation by constitutively active EGFR and potently inhibited EGFR-mediated ERK activation in fly glial cells. Long polyQ also limited the effect of activated EGFR on Drosophila eye development. Our results further indicate that the polyQ acts at an upstream step in the pathway, situated between EGFR and ERK activation. This suggests that disruption of EGFR signaling and ensuing glial cell dysfunction could play a direct role in the pathogenesis of HD and other polyQ diseases in humans.
MeSH Terms
- Animals
- Drosophila melanogaster
- ErbB Receptors
- Excitatory Amino Acid Transporter 1
- Extracellular Signal-Regulated MAP Kinases
- Eye
- Genes, Reporter
- Glutamic Acid
- Huntington Disease
- Longevity
- Neuroglia
- Peptides
- Signal Transduction
- Up-Regulation
- ras Proteins
Although in Fischer-344 rats, aging is associated with increased activation of EGF-receptor (EGFR) in mucosa of much of the gastrointestinal tract, including the colon, regulation of this process is poorly understood. We hypothesize that loss of suppressor of EGFR may partly be responsible for this process. To test this hypothesis, we examined the expression of EGFR related protein (ERRP), a recently identified negative regulator of EGFR, in the colonic mucosa during aging and following administration of the colonic carcinogen dimethylhydrazine (DMH) that resulted in the formation of aberrant crypt foci (ACF), which are considered to be precursor of adenoma and carcinoma. In Fischer-344 rats, aging is associated with increased activation of EGFR in the colonic mucosa, as evidenced by 30-35% increase in the levels of tyrosine phosphorylated EGFR in the proximal and distal colon of aged (20-22 months old) than in young (4-6 months old) rats. In contrast, the levels of ERRP in both regions of the colon of aged rats were decreased by 50-60%, compared to their younger counterparts. Administration of DMH, which induced a greater number of ACF in the colon of aged rats than in young animals, resulted in a corresponding reduction in ERRP in the colon. These results suggest that loss of ERRP expression is a common event during aging and early stages of chemically induced colon cancer. We also suggest that loss of ERRP could be a risk factor for developing colorectal cancer in the older population.
MeSH Terms
- 1,2-Dimethylhydrazine
- Aging
- Animals
- Carcinogens
- Colon
- Colonic Neoplasms
- ErbB Receptors
- Glycoproteins
- Male
- Rats
- Rats, Inbred F344
- Risk Factors
The model organism Caenorhabditis elegans is widely used for genetic studies as well as a living biomonitor in ecotoxicology. In this study, we investigated whether C. elegans may represent a suitable model for rapid preliminary toxicity studies of pharmaceutical compounds. For this purpose, we used the EGFR kinase inhibitors BIBU1361, BIBX1382, and an inactive chemical analogue BIBU1476. As a first parameter to score for toxicity, we determined lethality of the wild-type C. elegans strain N2 (Bristol) in the presence of the compounds. The transgenic C. elegans strain PC72 (lacZ, heat shock protein-16 [hsp-16] construct) was used as a report organism for toxic effects. PC72 expresses beta-Galactosidase which is induced by hsp-16 in direct response when exposed to toxic compounds. The expression of beta-Galactosidase in cells was subsequently visualized by histochemical staining with X-Gal. A rank order of potency with respect to lethality was established: BIBU1361>BIBX1382>>BIB1476. The induction of beta-Galactosidase was concentration-dependent for each compound and demonstrated the same order of potency as observed for lethality. Furthermore, these compounds showed the same order for lethality in rodents, the first requirement of validation. These results indicate that wild-type C. elegans and the transgenic strain PC72 are both suitable models to determine the toxicity of pharmaceutical compounds. This approach allows for an easy and fast ranking of compound toxicity, which may lead to a more rational choice for further in vivo tests.
MeSH Terms
- Animal Use Alternatives
- Animals
- Caenorhabditis elegans
- Caenorhabditis elegans Proteins
- Dose-Response Relationship, Drug
- Enzyme Inhibitors
- Heat-Shock Proteins
- Histocytochemistry
- Lethal Dose 50
- Longevity
- Models, Animal
- Organic Chemicals
- Organisms, Genetically Modified
- Piperidines
- Pyrimidines
- Toxicity Tests
- beta-Galactosidase
Previous studies demonstrating olfactory interneuron involvement in olfactory discrimination and decreased proliferation in the forebrain subventricular zone with age led us to ask whether olfactory neurogenesis and, consequently, olfactory discrimination were impaired in aged mice. Pulse labeling showed that aged mice (24 months of age) had fewer new interneurons in the olfactory bulb than did young adult (2 months of age) mice. However, the aged mice had more olfactory interneurons in total than their younger counterparts. Aged mice exhibited no differences from young adult mice in their ability to discriminate between two discrete odors but were significantly poorer at performing discriminations between similar odors (fine olfactory discrimination). Leukemia inhibitory factor receptor heterozygote mice, which have less neurogenesis and fewer olfactory interneurons than their wild-type counterparts, performed more poorly at fine olfactory discrimination than the wild types, suggesting that olfactory neurogenesis, rather than the total number of interneurons, was responsible for fine olfactory discrimination. Immunohistochemistry and Western blot analyses revealed a selective reduction in expression levels of epidermal growth factor (EGF) receptor (EGFR) signaling elements in the aged forebrain subventricular zone. Waved-1 mutant mice, which express reduced quantities of transforming growth factor-alpha, the predominant EGFR ligand in adulthood, phenocopy aged mice in olfactory neurogenesis and performance on fine olfactory discrimination tasks. These results suggest that the impairment in fine olfactory discrimination with age may result from a reduction in EGF-dependent olfactory neurogenesis.
MeSH Terms
- Aging
- Animals
- Cell Count
- Cell Proliferation
- Cells, Cultured
- Discrimination, Psychological
- ErbB Receptors
- Heterozygote
- Interneurons
- Lateral Ventricles
- Leukemia Inhibitory Factor Receptor alpha Subunit
- Mice
- Mice, Inbred Strains
- Mice, Mutant Strains
- Olfactory Bulb
- Receptors, Cytokine
- Receptors, OSM-LIF
- Signal Transduction
- Smell
- Stem Cells
- Stimulation, Chemical
- Transforming Growth Factor alpha
The increase in the aging population has led to a growing interest in achieving a better understanding of the aging process and of diseases that are predominantly expressed during advancing age. Since the structural and, in turn, the functional integrity of the mucosa of the gastrointestinal tract (GI) are maintained by constant renewal of cells, a detailed knowledge of the events that initiate and regulate mucosal proliferative processes is essential for a better understanding of the normal aging process as well as age-associated dysfunctions, including malignancy that represent disorders of tissue growth. In Fischer-344 rats, aging is associated with increased mucosal proliferative activity in much of the GI tract. On the other hand, the functional properties are either decreased or remain unchanged during advancing age. Basal gastric acid and pepsin output decline during aging, as is gastrin secretion. In contrast, antral gastrin levels increase during this period, as is mucosal histidine decarboxylase activity. The age-related decline in gastrin secretion could partly be attributed to a higher ratio of somatostatin (D) to gastrin (G) cells in the antral mucosa. The age-related rise in GI mucosal proliferative activity could not be attributed to the trophic action of either gastrin or bombesin, since they caused no significant change in mucosal proliferation in aged rats. On the other hand, EGF and TGF-alpha appear to be involved in regulating mucosal proliferation during aging. Aging is associated with increased activation of EGF-receptor (EGFR), the common receptor for EGF and TGF-alpha. This could be due to (a) increased levels of membrane-bound precursor form(s) of TGF-alpha resulting in increased activation EGFR signaling processes through an autocrine/paracrine mechanism, (b) heightened sensitivity of mucosal EGFR to EGF and TGF-alpha such that comparatively lower levels of these peptides are required to activate EGFR in aged than in young animals and/or (c) loss of EGFR regulatory factor(s) such as ERRP (EGFR Related Protein), a "negative regulator" of EGFR.
MeSH Terms
- Aging
- Animals
- Gastric Mucosa
- Gastrointestinal Tract
- Humans
Aging is often characterized by reduced stress tolerance and decreased proliferative capacity, but little is known about the effects of aging on signaling pathways important in regulating these responses. Recent studies from our laboratory have implicated impairments in epidermal growth factor receptor (EGFR) signaling and extracellular signal-regulated kinase (ERK) activation to both effects in rat hepatocytes. Here we investigated the responsiveness of hepatocytes derived from young (4-5 months) and aged (24-29 months) mice to proliferative signals (low concentrations of H2O2 and epidermal growth factor [[[EGF]]] stimulation), and oxidant injury (high H2O2 concentrations). Old hepatocytes displayed lower levels of DNA synthesis in response to low H(2)O(2) concentrations (5-10 microM) and EGF stimulation, and reduced survival following treatment with high H2O2 concentrations (20-50 microM). Both effects were associated with reduced activation of ERK and diminished phosphorylation of EGFR tyrosine residue 1173. p38 was also activated by H2O2, but to a greater extent in old cells. Pharmacologic inhibition of ERK increased the sensitivity of young cells to H2O2-induced cell death, while inhibition of p38 decreased the sensitivity of old cells. Our findings suggest that impairments in common signaling events underlie age-related declines in proliferative capacity and oxidative stress tolerance in mouse hepatocytes, and that an imbalance in ERK and p38 activities contributes to the greater sensitivity of aged cells to H2O2.
MeSH Terms
- Aging
- Animals
- Antimetabolites
- Bromodeoxyuridine
- Cell Division
- Cell Survival
- DNA
- Dose-Response Relationship, Drug
- Enzyme Inhibitors
- ErbB Receptors
- Free Radicals
- Hepatocytes
- Hydrogen Peroxide
- Kinetics
- Male
- Mice
- Mice, Inbred C57BL
- Mitogen-Activated Protein Kinases
- Oxidative Stress
- Phosphorylation
- Signal Transduction
- Time Factors
- p38 Mitogen-Activated Protein Kinases
Aging and gastrointestinal malignancies, including that of the stomach are associated with increased activation of EGF-receptor (EGFR). Although the intracellular events that regulate this process are poorly understood, we hypothesize that loss of ERRP (EGFR-related protein; GenBank accession number AF187818), a recently identified negative regulator of EGFR, that possesses a substantial homology to the ligand binding extracellular domain of EGFR, may contribute to this event. In support of our hypothesis, we have observed that in Fischer-344 rats, whereas aging is associated with increased activation of EGFR in the gastric mucosa, expression of ERRP decreases inthis tissue during this period. The latter is accompanied by a concomitant reduction in the amount of TGF-alpha bound to ERRP. In contrast, the amount of TGF-alpha bound to EGFR is found to be higher in the gastric mucosa of aged than in young rats. This is accompanied by a concomitant rise in EGFR levels. In the gastric mucosa, EGFR and ERRP are found to be colocalized. Gastric adenocarcinoma in humans, which has been shown to be associated with increased activation of EGFR, shows a substantial reduction in ERRP expression, when compared with benign tissues. We conclude that increased activation of EGFR in the gastric mucosa during aging and carcinogenesis may partly be due to the loss of ERRP.
MeSH Terms
- Aging
- Animals
- Base Sequence
- Biopsy, Needle
- Blotting, Western
- Cell Transformation, Neoplastic
- Cells, Cultured
- ErbB Receptors
- Gastric Mucosa
- Gene Expression Regulation
- Genes, erbB-1
- Glycoproteins
- Immunohistochemistry
- Male
- Models, Animal
- Molecular Sequence Data
- Probability
- Rats
- Rats, Inbred F344
- Receptor, ErbB-2
- Risk Assessment
- Sensitivity and Specificity
- Stomach Neoplasms
Although the age-related activation of EGF receptor (EGFR) in the gastric mucosa of Fischer 344 rats is associated with increased DNA binding activity of activator protein-1 (AP-1), little is known about the EGFR signaling cascades that regulate this process. The primary objective of this investigation was to determine the role of signaling pathways initiated by EGFR in regulating the transforming growth factor-alpha (TGF-alpha)-induced activation of AP-1 in the gastric mucosa in aged rats. Freshly isolated gastric mucosal cells from male young (4-5 mo) and aged (22-24 mo) rats were used. We have observed that although exposure of mucosal cells from young (4-5 mo) and old (22-24 mo) rats to 1 nM TGF-alpha for 20 min stimulates the DNA binding activity of AP-1 in both age groups, the magnitude of stimulation is substantially higher in aged (131%) than in young (35%) rats. This stimulation in the aged is associated with a concomitant activation of MEKs and ERKs, but not JNKs and p38. The TGF-alpha induction of AP-1 transcriptional activity in gastric mucosal cells from aged rats could be totally abrogated by either PD153035, a specific inhibitor of EGFR tyrosine kinase, or PD98059, a specific inhibitor of MEKs, but not by Wortmannin, which inhibits phosphatidylinositol kinase. PP2, a specific inhibitor of Src kinase, produces a 50% inhibition of the TGF-alpha-induced activation of AP-1 transcriptional activity. Our results suggest that the TGF-alpha-induced stimulation of DNA binding activity of AP-1 in the gastric mucosa of aged rats is primarily through a signaling pathway involving MEKs and ERKs, whereas Src kinase pathways play a minor role.
MeSH Terms
- Aging
- Animals
- DNA
- Enzyme Activation
- Enzyme Inhibitors
- ErbB Receptors
- Flavonoids
- Gastric Mucosa
- Male
- Mitogen-Activated Protein Kinase Kinases
- Pyrimidines
- Quinazolines
- Rats
- Rats, Inbred F344
- Signal Transduction
- Transcription Factor AP-1
- Transforming Growth Factor alpha
- src-Family Kinases
Glioblastoma multiforme (GBM) is a major cause of morbidity and mortality in neurosurgical patients. Despite the overall poor prognosis a range in survival times exists. Many approaches have been undertaken to define patient subgroups based on molecular changes. The aim of this study was to assess a possible correlation between the immunohistochemical p53, Mdm2, EGFR and Msh2 expression and age. 143 patients (77 male, 66 female) were included in this retrospective study who underwent craniotomy for newly-diagnosed GBM between May 1994 and February 2000. For statistical analysis, patients were separated into three age groups: 1. < 40 years, 2. 40-60 years, 3. > 60 years. Immunohistochemical staining (IHC) was performed using anti-p53 (clone DO-1), anti-Mdm2 (clone IF-2), anti-EGFR (clone H11) and anti-Msh2 antibodies (clone AB-1). The results were compared with the Ki67/MIB-1 proliferation index (Ki67 PI) and patient survival. P53 protein expression was significantly decreasing with advanced age (p < 0.05) whereas EGFR and Mdm2 expression was increasing (p < 0.05; p=0.01). Msh2 expression was unrelated to age. Multivariate analysis revealed Msh2 protein expression as a significant predictor of prolonged survival (p=0.004) whereas p53, Mdm2 and EGFR were not associated with patient survival. P53, Mdm2, EGFR and Msh2 expression was not associated with the Ki67 PI. Our results support the hypothesis that in GBM patients a complex relationship exists between the p53, Mdm2 and EGFR expression and age. Msh2 expression is not related to age. Notably, nuclear Msh2 expression turned out to be an independent prognostic indicator.
MeSH Terms
- Adolescent
- Adult
- Aged
- Aged, 80 and over
- Aging
- Base Pair Mismatch
- Cell Division
- Child
- Child, Preschool
- Craniotomy
- DNA Repair
- DNA-Binding Proteins
- Female
- Genes, erbB-1
- Genes, p53
- Glioblastoma
- Humans
- Immunohistochemistry
- Infant
- Ki-67 Antigen
- Male
- Middle Aged
- MutS Homolog 2 Protein
- Nuclear Proteins
- Prognosis
- Proto-Oncogene Proteins
- Proto-Oncogene Proteins c-mdm2
- Retrospective Studies
- Survival Analysis
To explore the changes of epidermal growth factor (EGF) and epidermal growth factor receptor (EGFR) expressions in cryptorchid children and their clinical significance. The level of serum EGF was measured by radioimmunoassay (RIA) and the expression of EGFR by immunohistochemistry. (1) The level of serum EGF was significantly lower in cryptorchid children than in normal subjects at age group of 5-9 years (P<0.01) and 10-14 years (P<0.01), (2) The level of EGF was significantly lower in boys with impalpable testis than in those with extracanalicular and intracanalicular testes (P<0.01), (3) The serum EGF level increased significantly 6 months after orchiopexy (P<0.05), (4) The EGFR expression in testicular Leydig's cells was lower in 2 approximately 4 year-old boys than in those over 5 years (P<0.05) and (5) the EGFR expression was less positive in the impalpable group and the intracanalicular group than that of the extracanalicular group (P<0.01). The EGF and EGFR expressions may correlate with the age and the position of testes; orchiopexy improves the EGF and EGFR expressions in cryptorchid boys.
MeSH Terms
- Adolescent
- Aging
- Biomarkers
- Child
- Child, Preschool
- Cryptorchidism
- Epidermal Growth Factor
- ErbB Receptors
- Humans
- Immunohistochemistry
- Leydig Cells
- Male
It has been established that thyroid hormone and neurotrophic factors both orchestrate developmental events in the brain. However, it is not clear how these two influences are related. In this study, we investigated the effects of thyroid hormone on cerebellar development and the coincident expression of transforming growth factor-alpha (TGF-alpha), a ligand in the epidermal growth factor (EGF) family, and the epidermal growth factor receptor (EGFR). Profiles of thyroid hormone expression were measured in postnatal animals and were found to peak at postnatal day 15 (P15). These levels dropped below detectable levels when mice were made hypothyroid with propylthiouracil (PTU). TGF-alpha and EGFR expression, as determined by RNAse protection assay, was maximal at P6 in normal animals, but remained low in hypothyroid animals, suggesting that thyroid hormone was responsible for their induction. In situ hybridization and immunohistochemical analysis of EGFR expression revealed that this receptor was present on granule cells within the inner zone of the external granule cell layer (EGL), suggesting that EGFR-ligands were not inducing granule cell proliferation. The persistence of EGFR expression on migrating granule cells and subsequent down-regulation of expression in the internal granule cell layer (IGL) implicates a role for EGFR-ligands in differentiation and/or migration. In hypothyroid animals, we observed a delayed progression of granule cell migration, consistent with the persistence of EGFR labeling in the EGL, and in the 'pile-up' of labeled cells at the interface between the molecular layer and the Purkinje cell layer. Taken together, these results implicate thyroid hormone in the coordinated expression of TGF-alpha and EGFR, which are positioned to play a role in post-mitotic developmental events in the cerebellum.
MeSH Terms
- Aging
- Animals
- Cerebellum
- ErbB Receptors
- Female
- Gene Expression Regulation
- Glial Fibrillary Acidic Protein
- Hypothyroidism
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Inbred CBA
- Mitosis
- Propylthiouracil
- Reference Values
- Thyroid Gland
- Thyroxine
- Transcription, Genetic
We examined whether lung growth after pneumonectomy (PNX) invokes normal signaling pathways of postnatal development. We qualitatively and quantitatively assessed the immunoexpression of epidermal growth factor (EGF), its receptor (EGFR), surfactant proteins (SP) [SP-A and -D and surfactant proproteins (proSP)-B and -C] and proliferating cell nuclear antigen (PCNA) in immature and mature dog lung. We also assayed these proteins in lungs of immature dogs 3 wk or 10 mo after they underwent right PNX compared with simultaneous matched sham controls. During maturation, alveolar cell proliferation is regionally regulated in parallel with EGF and EGFR levels and inversely correlated with SP-A and proSP-C levels. In contrast, post-PNX lung growth is not associated with EGF or EGFR upregulation but with markedly increased SP-A level and moderately increased SP-D level; proSP-B and proSP-C levels did not change. We conclude that 1) signaling of EGF axis and differential regulation of SPs persist during postnatal lung development, 2) post-PNX lung growth is not a simple recapitulation of maturational responses, and 3) SP-A and SP-D may modulate post-PNX lung growth.
MeSH Terms
- Aging
- Animals
- Dogs
- Epidermal Growth Factor
- ErbB Receptors
- Lung
- Pneumonectomy
- Proliferating Cell Nuclear Antigen
- Protein Precursors
- Proteolipids
- Pulmonary Surfactant-Associated Protein A
- Pulmonary Surfactant-Associated Protein D
- Regeneration
To explore the hypothesis that aging not only increases breast cancer incidence but also alters breast cancer biology, we correlated patient age and diagnosis with tumor histology, stage and biomarkers independently determined from two different tumor archives: an American collection of approximately 800 paraffin-embedded and immunohistochemically analyzed primary breast cancers, and an European collection of approximately 3000 cryobanked primary breast cancers analyzed by ligand-binding and enzyme immunoassay (EIA). The prognostic biomarkers chosen for comparison represented surrogate measures of tumor: (i). proliferation, growth and genetic instability (mitotic and apoptotic indices, Ki-67/MIB-1-positivity, nuclear grade, p53-positivity), (ii). endocrine-dependence (estrogen receptor (ER), progesterone receptors (PR), pS2, Bcl2), (iii). growth factor receptor-dependence (ErbB2, EGFR/ErbB1), and (iv). angiogenic, invasive and proteolytic potential (uPA, PAI-1, Cathepsin D, VEGF). No biomarker reflecting tumor angiogenic, invasive or proteolytic potential showed a significant correlation with patient age at diagnosis. In contrast, significant inverse correlations (
MeSH Terms
- Adult
- Aged
- Aged, 80 and over
- Aging
- Americas
- Biomarkers, Tumor
- Breast Neoplasms
- Cathepsin D
- Data Interpretation, Statistical
- Endothelial Growth Factors
- ErbB Receptors
- Europe
- Female
- Humans
- Intercellular Signaling Peptides and Proteins
- Ki-67 Antigen
- Lymphokines
- Middle Aged
- Plasminogen Activator Inhibitor 1
- Receptor, ErbB-2
- Receptors, Estrogen
- Tumor Suppressor Protein p53
- Urokinase-Type Plasminogen Activator
- Vascular Endothelial Growth Factor A
- Vascular Endothelial Growth Factors
We hypothesize that various growth factors and their receptors gene and protein are modulated in dorsal and ventral lobes of aging prostate. To test this hypothesis, TGFbeta1, TGFbeta2 TGFbeta3, TGFbetaR-I, TGFbetaR-II, TGFalpha, EGF, EGFR, KGF and KGFR gene and protein expression were analyzed in dorsal and ventral lobes of aging rat prostates (1, 3, 6, 9, 12, 18, 24, and 28/30 months). KGF gene expression was very weak or absent in 1, 3, and 6 month old rat dorsal and ventral lobes of prostate whereas it re-expressed in 9, 12, 18, 24 and 30 month old rat prostate. All growth factors and their receptors expect KGF and EGFR were mainly localized in epithelium of ventral and dorsal lobes of aging rat prostates. EGF, TGFalpha, TGFbeta1, and TGFbetaR-I protein expression was lacking in stroma of dorsal and ventral lobes of 1, 3, 6, 9, 12/18 months old rat prostates. However, EGF, TGFbeta1 and TGFbetaR-I proteins re-expressed in stroma of 24 and 28 months old rat prostates. KGF protein expression was lacking in epithelium of dorsal and ventral lobes of all aging rat prostates. This is the first report to demonstrate differential gene and protein expression of growth factors in dorsal and ventral lobes is associated with aging rat prostate, suggesting their role in pathogenesis of prostatic diseases with aging.
MeSH Terms
- Aging
- Animals
- Epidermal Growth Factor
- ErbB Receptors
- Fibroblast Growth Factor 7
- Fibroblast Growth Factors
- Growth Substances
- Immunohistochemistry
- Kinetics
- Male
- Prostate
- RNA, Messenger
- Rats
- Rats, Sprague-Dawley
- Receptor, Fibroblast Growth Factor, Type 2
- Receptors, Fibroblast Growth Factor
- Receptors, Transforming Growth Factor beta
- Transcription, Genetic
- Transforming Growth Factor alpha
- Transforming Growth Factor beta
Although aging is associated with increased epidermal growth factor receptor (EGFR) tyrosine kinase activity in Fischer 344 rat gastric and colonic mucosa, the regulatory mechanisms for the age-related rise in EGFR tyrosine kinase are poorly understood. Transmembrane transforming growth factor-alpha (TGF-alpha) may modulate EGFR function through an autocrine/juxtacrine mechanism. The present study aimed to determine the contribution of membrane-bound precursors of TGF-alpha in enhancing EGFR activation in the gastric and colonic mucosa during aging. The extent of EGFR tyrosine phosphorylation, a measure of EGFR activation, was substantially higher (300--350%) in the gastric and colonic mucosa of 23- (aged) vs. 4-mo-old (young) Fischer 344 rats. This was accompanied by an increase (200--1,000%) in the relative concentration of 18- to 20-kDa membrane-bound precursor forms of TGF-alpha. The amount of TGF-alpha bound to EGFR was also higher (150-250%) in the gastric and colonic mucosa of aged vs. young rats. In vitro studies revealed that exposure of HCT 116 cells (a colon cancer cell line) to TGF-alpha from gastric and colonic mucosal membranes of aged rats caused a 200--250% higher activation of EGFR and extracellular signal-related kinases (p42/44) compared with young rats. Our data suggest that the membrane-bound precursor form(s) of TGF-alpha may partly be responsible for enhancing EGFR activation in the gastric and colonic mucosa of aged rats, probably though an autocrine/juxtacrine mechanism(s).
MeSH Terms
- Aging
- Animals
- Autocrine Communication
- Colon
- ErbB Receptors
- Gastric Mucosa
- In Vitro Techniques
- Intestinal Mucosa
- MAP Kinase Signaling System
- Male
- Mitogen-Activated Protein Kinase 1
- Mitogen-Activated Protein Kinase 3
- Mitogen-Activated Protein Kinases
- Rats
- Rats, Inbred F344
- Transforming Growth Factor alpha
Although aging enhances expression and tyrosine kinase activity of epidermal growth factor receptor (EGFR) in the gastric mucosa, there is no information about EGFR signaling cascades. We examined the age-related changes in mitogen-activated protein kinases (MAPKs) [extracellular signal-related kinases (ERKs), c-Jun NH(2)-terminal kinases (JNKs), and p38], an EGFR-induced signaling cascade, and activator protein-1 (AP-1) and nuclear factor-kappaB (NF-kappaB) transcriptional activity in the gastric mucosa of 4- to 6-, 12- to 14-, and 22- to 24-mo-old Fischer 344 rats. AP-1 and NF-kappaB transcriptional activity in the gastric mucosa rose steadily with advancing age. This can be further induced by transforming growth factor-alpha. The age-related activation of AP-1 and NF-kappaB in the gastric mucosa was associated with increased levels of c-Jun, c-Fos, and p52, but not p50 or p65. Total and phosphorylated IkappaBalpha levels in the gastric mucosa were unaffected by aging. Aging was also associated with marked activation of ERKs (p42/p44) and JNK1. In contrast, aging decreased p38 MAPK activity in the gastric mucosa. Our observation of increased activation of ERKs and JNK1 in the gastric mucosa of aged rats suggests a role for these MAPKs in regulating AP-1 and NF-kappaB transcriptional activity. These events may be responsible for the age-related rise in gastric mucosal proliferative activity.
MeSH Terms
- Aging
- Animals
- Gastric Mucosa
- I-kappa B Proteins
- JNK Mitogen-Activated Protein Kinases
- Male
- Mitogen-Activated Protein Kinase 8
- Mitogen-Activated Protein Kinases
- NF-kappa B
- NF-kappa B p50 Subunit
- Phosphorylation
- Proto-Oncogene Proteins c-fos
- Proto-Oncogene Proteins c-jun
- Rats
- Rats, Inbred F344
- Transcription Factor AP-1
- Transcription, Genetic
- Transforming Growth Factor alpha
- p38 Mitogen-Activated Protein Kinases
Administration of pharmacological doses of epidermal growth factor (EGF) or transforming growth factor-alpha (TGF-alpha) in young rats stimulates gastric mucosal proliferation, but, in aged rats, the same treatment inhibits proliferation. This may be due to enhanced ligand-induced internalization of EGF receptor (EGFR). In support of this, we demonstrated that although a single injection of EGF (10 microg/kg) or TGF-alpha (5 microg/kg) in young (4-6 mo old) rats greatly increased membrane-associated EGFR tyrosine kinase activity, the same treatment slightly inhibited the enzyme activity in aged (24 mo old) rats. This treatment also produced a greater abundance of punctate cytoplasmic EGFR staining in gastric epithelium of aged rats, consistent with EGFR internalization. In vitro analyses demonstrated that exposure of isolated gastric mucosal cells from aged but not young rats to 100 pM TGF-alpha resulted in marked increases in intracellular EGFR tyrosine kinase activity and that induction of EGFR tyrosine kinase activity in mucosal membranes from aged rats occurred at doses 1,000-fold less than those required in young rats. Our data suggest that aging enhances sensitivity of the gastric mucosa to EGFR ligands. This may partly explain EGFR-mediated inhibition of gastric mucosal proliferation in aged rats.
MeSH Terms
- Aging
- Animals
- Cell Division
- Cell Membrane
- Cytosol
- Epidermal Growth Factor
- ErbB Receptors
- Gastric Mucosa
- Male
- Rats
- Rats, Inbred F344
- Receptor Protein-Tyrosine Kinases
- Transforming Growth Factor alpha
In this study the mRNAs encoding epidermal growth factor receptor (EGFR), basic fibroblast growth factor receptor (FGFR-2) and insulin-like growth factor receptor (IGFR-1) genes of the human normal lenses at ages varying from 0.5 to 72 years, were identified by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR). Regulation of EGFR gene expression in the lens did not change with aging, and of FGFR-2 and IGFR-1 genes also remained unaltered up to age 53 years. However, expressions of FGFR-2 and IGFR-1 genes were decreased at ages above 60 years. EGFR, FGFR-2 and IGFR-1 proteins were detected by immunoblot analysis in the epithelial cell membranes of lens at age varying from 40 to 72 years. There was no detectable amount of EGFR protein in fiber cell membranes of the lens, and the levels of FGFR-2 and IGFR-1 proteins were much lower than those in the epithelial cell membranes. The low levels of these receptor proteins in the fiber cell membranes of lens, suggest their possible role in keeping the differentiated function of these unique transparent cells. The findings of the increased protein levels with age of EGFR with the appearance of some degradation products at age 48 years and higher, and the increased FGFR-2 protein at age 60 years and higher in the epithelial cell membranes of lens, were of interest. It appears that this could be a compensatory protective response of the lens to aging process for lifelong continuation of normal growth by proliferation and differentiation of its epithelial cells into new fiber cells in the germinative zone at the equatorial region. Thus, these results could provide a basis for further studies on growth factor receptor gene and protein regulations in the mechanism of lens aging and progression of age-related human cataract.
MeSH Terms
- Adolescent
- Adult
- Aged
- Aging
- Base Sequence
- Cataract
- Child
- Child, Preschool
- DNA Primers
- ErbB Receptors
- Gene Expression Regulation, Developmental
- Humans
- Infant
- Lens, Crystalline
- Middle Aged
- RNA, Messenger
- Receptor Protein-Tyrosine Kinases
- Receptor, Fibroblast Growth Factor, Type 2
- Receptor, IGF Type 1
- Receptors, Fibroblast Growth Factor
To clarify the mechanisms of age-related changes in the olfactory epithelium, we investigated age-related changes in epidermal growth factor receptors (EGFRs) in the epithelium. We examined 3 mice at each of the following stages: embryonal (embryonic days 14 and 16), neonatal (postnatal days 1 and 7), adult (postnatal weeks 5 and 12), and aged (postnatal years 1.5 to 2). The olfactory epithelium of each mouse was stained with sheep anti-human EGFR polyclonal IgG by an immunohistochemical method. The EGFRs were observed in all layers of the olfactory epithelium at the embryonal and neonatal stages. They were identified only in the basal layer of the olfactory epithelium at adult and aged stages, and the number of regions in which EGFRs were identified in the basal layer of the olfactory epithelium decreased in aged mice compared to adult mice. We believe that a decrease in EGFRs in the olfactory epithelium induces the inhibition of cell proliferation, with resultant atrophy of the olfactory epithelium.
MeSH Terms
- Aging
- Animals
- Animals, Newborn
- Epidermal Growth Factor
- ErbB Receptors
- Immunohistochemistry
- Mice
- Olfactory Mucosa
We have previously demonstrated that exposure to genistein early in life protects against chemically-induced mammary cancer in rats. To gain insight into the mechanism of action, we have investigated the expression of the EGF-signaling pathway in the mammary glands of 21 and 50 day old rats treated on days 16, 18, and 20 postpartum with 500 microg genistein/g body weight (B.W.) or an equivalent volume of the vehicle, dimethylsulfoxide (DMSO). This prepubertal genistein treatment up-regulated TGF-alpha and the EGF-receptor (EGFR), but not EGF, in mammary terminal ductal structures at day 21 postpartum. TGF-alpha, EGF and EGFR mRNA levels were similar in 21 day old control- and genistein-treated animals. At day 50 postpartum, mammary glands of genistein treated rats had more lobules and fewer terminal end buds (TEBs) and terminal ducts (TDs), i.e. they were more differentiated. TGF-alpha mRNA levels were down-regulated in TEB of proestrous and estrous females; EGF mRNA levels were down-regulated in TDs of proestrous, but not in estrous females; and EGFR mRNA levels were not altered in 50 day old proestrous or estrous female rats. EGFR immunostaining intensity was decreased in TEBs, but not in the total gland. EGF was increased in TEBs and TDs. TGF-alpha, EGF and EGFR were also observed in the stroma and fat pad, but genistein treatment did not alter the expression of these proteins in those locations. TGF-alpha, but not EGF and EGFR, immunostaining was observed in cell nuclei (not modulated by genistein), suggesting that this growth factor may act directly on nuclear events such as transcription and DNA replication. For comparative purposes, prepubertal diethylstilbestrol treatment was investigated and found to decrease EGFR immunostaining intensity and total IHC staining in all terminal ductal structures. We conclude that prepubertal genistein treatment directly stimulates TGF-alpha and EGFR to enhance mammary gland differentiation. This programs the differentiated cells for a down-regulated EGF-signaling pathway in TEBs and TDs of adult mammary glands. Reduced EGFR expression at time of carcinogen exposure may account for genistein programming against mammary cancer.
MeSH Terms
- Adipose Tissue
- Aging
- Animals
- Cell Membrane
- Cell Nucleus
- Connective Tissue Cells
- Diethylstilbestrol
- Epidermal Growth Factor
- Epithelial Cells
- ErbB Receptors
- Estrus
- Female
- Genistein
- Immunohistochemistry
- Lymph Nodes
- Mammary Glands, Animal
- Rats
- Rats, Sprague-Dawley
- Reverse Transcriptase Polymerase Chain Reaction
- Signal Transduction
- Transforming Growth Factor alpha
Aging is associated with decreased reparative ability of the gastric mucosa. Our recent data suggest a role for epidermal growth factor receptor (EGFR) in the mucosal reparative processes. Thus we examined changes in EGFR tyrosine kinase activity as well as expression and subcellular localization of EGFR and its ligand transforming growth factor-alpha (TGF-alpha) in the gastric mucosa of young (4-mo-old) and aged (24-mo-old) Fischer 344 male rats during the early reparative phase after acute injury induced by 2 M NaCl. Within 240 min of injury, significant epithelial restitution was observed in the gastric mucosa of young but not of aged rats. Expansion of the neck region and initiation of foveolar cell migration could be seen within 45 min of injury in young rats but not until 90 min in aged rats. In young rats mucosal EGFR tyrosine kinase activity increased at 45 min after injury and subsequently fell to basal levels. Mucosal EGFR mRNA increased throughout the reparative phase as did content of the EGFR ligand TGF-alpha. In contrast, although the basal tyrosine kinase activity and levels of EGFR mRNA and TGF-alpha were elevated in the gastric mucosa of aged rats, injury did not cause increases in these parameters. Immunofluorescent localization suggests that internalization and/or degradation of EGFR may be higher in aged than in young rats. We suggest that diminished induction of EGFR tyrosine kinase activity and increased EGFR internalization after injury may in part be responsible for the age-related decrease in the reparative capacity of the gastric mucosa.
MeSH Terms
- Aging
- Animals
- ErbB Receptors
- Formaldehyde
- Gastric Mucosa
- Gene Expression Regulation, Developmental
- Male
- Rats
- Rats, Inbred F344
- Time Factors
Deregulated expression of one or more growth control genes including p16, p53, EGF receptor (EGFR), MDM2 or Bcl-2 may contribute to the treatment resistance phenotype of GBM and generally poor patient survival. Clinically, GBM have been divided into two major groups defined by (1) histologic progression from a low grade tumor ("progressive" or "secondary" GBM) contrasted with (2) those which show initial clinical presentation without a prior history ("de novo" or "primary" GBM). Using molecular genetic analysis for p53 gene mutations together with immunophenotyping for overexpression of EGFR, up to four GBM variants can be distinguished, including the p53 /EGFR- progressive or the p53-/EGFR de novo variant. We examined the survival of 80 adult patients diagnosed with astrocytic GBM stratified by age category (>40, 41-60 or 61-80) to determine whether alterations in any one given growth control gene or whether different genetic variants of GBM (progressive versus de novo) were associated with different survival outcomes. Survival testing using Kaplan-Meier plots for GBM patients with or without altered expression of p16, p53, EGFR, MDM2 or Bcl-2 showed no significant differences by age group or by gene expression indicating a lack of prognostic value for GBM. Also the clinical outcome among patients with GBM showed no significant differences within each age category for any GBM variant including the progressive and de novo GBM variants indicating similar biologic behavior despite different genotypes. Using a pairwise comparison, one-third of the GBM with normal p16 expression showed accumulation of MDM2 protein and this association approached statistical significance (0.01 < P < 0.05) using the Bonferroni procedure. These GBM may represent a variant in which the p19ARF/MDM2/p53 pathway may be deregulated rather than the p16/cyclin D-CDK4/Rb pathway.
MeSH Terms
- Adult
- Aged
- Aged, 80 and over
- Aging
- Brain Neoplasms
- ErbB Receptors
- Female
- Gene Expression Regulation, Neoplastic
- Genes, bcl-2
- Genes, p16
- Genes, p53
- Glioblastoma
- Humans
- Immunohistochemistry
- Male
- Middle Aged
- Nuclear Proteins
- Polymorphism, Single-Stranded Conformational
- Proto-Oncogene Proteins
- Proto-Oncogene Proteins c-mdm2
- Receptor, ErbB-2
- Survival
At doses of 10-115 microg/kg, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) decreased body and adipose tissue weights of mature female rats. Doses below 10 microg TCDD/kg decreased body and adipose tissue weights of immature, but not mature females. Doses of 2 and 10 microg TCDD/kg decreased adipose tissue epidermal growth factor receptor (EGFR) binding activity 5 and 7 days later in immature and mature females, respectively. At these times, there was a decrease in the activities of tyrosine kinase (TK), mitogen-activated protein kinase (MAP2K), and protein kinase A (PKA). In mature females, estradiol (E2, 15 microg/kg) increased TK and PKA activities and decreased MAP2K activity. In immature females, E2 decreased TK and PKA activities but not MAP2K activity. TCDD abolished the stimulatory effect of E2 on TK and PKA in mature females, and in immature females TCDD potentiated the negative effect of E2 on all three kinases. TCDD decreased binding of [3H]E2 to cytosolic and nuclear estrogen receptors (ERs) of mature and immature females, and antagonized the stimulatory effect of E2 on ER binding activity. E2 increased DNA binding activity of the estrogen response element (ERE) and activator protein-1, and TCDD antagonized this effect. Geldanamycin, an inhibitor of Src tyrosine kinase, reduced the effects of TCDD on body and adipose tissue weights. Geldanamycin antagonized the effects of TCDD on EGFR binding activity and TK activity. In cell-free preparations, TCDD antagonized E2 action on TK activity in mature females, as well as E2 action on PKA activity in immature females. We hypothesize that TCDD antagonizes E2 action in female adipose tissues through disruption of common cytosolic signal transduction pathways.
MeSH Terms
- Adipose Tissue
- Aging
- Animals
- Benzoquinones
- Body Weight
- Cell-Free System
- Dose-Response Relationship, Drug
- Enzyme Inhibitors
- ErbB Receptors
- Estradiol
- Female
- Lactams, Macrocyclic
- Organ Size
- Phosphorylation
- Polychlorinated Dibenzodioxins
- Protein Kinase Inhibitors
- Protein Kinases
- Quinones
- Rats
- Rats, Sprague-Dawley
- Signal Transduction
- Time Factors
To clarify the role of epidermal growth factor receptor (EGFR) in brain development, especially with regard to neuron differentiation, EGFR mRNA expression was studied by in situ hybridization in embryonic day (E)12, E16, postnatal day (P)1, P4, P15, P29 and adult rat, using protein gene product (PGP) 9.5 as a neuron marker. The primary germinal zone (neuroepithelium) expressed neither PGP 9.5 immunoreactivity (IR) nor EGFR mRNA. In the developing brain, cells expressing EGFR mRNA but not PGP 9.5 IR were found in the secondary germinal zone such as the subventricular zone and cerebellar external germinal layer, the cortical plate and, in later stage animals, the fiber tracts. Cells expressing both EGFR mRNA and PGP 9.5 IR appeared in a differentiating field. In the adult brain, strong EGFR mRNA expression was observed in Purkinje cells, Golgi cells, some hippocampal cells and neurons of the diencephalon, pontine and medullary nuclei, and weak expression was seen in neurons of the cerebral cortex. These results suggest that EGFR is related to the process of differentiation and maturation of neurons and the maintenance of some types of adult neurons.
MeSH Terms
- Aging
- Animals
- Brain
- Embryo, Mammalian
- Embryonic and Fetal Development
- ErbB Receptors
- Neurons
- RNA, Messenger
- Rats
- Rats, Wistar
- Thiolester Hydrolases
- Tissue Distribution
- Ubiquitin Thiolesterase
The epidermal growth factor (EGF) system has been thought to play an important role in normal mammary development and carcinogenesis. To study the role of the EGF receptor (EGFR) in mammary development, we developed a transgenic mouse model in which a C-terminal truncated mouse EGFR (EGFR-TR) was expressed in the mouse mammary epithelium under the control of the mouse mammary tumor virus long terminal repeat. The EGFR-TR lacks most of the cytoplasmic domain of the receptor, including the entire protein tyrosine kinase domain. In cultured cells, we show that it acts in a dominant negative manner in EGF-signaled EGFR autophosphorylation. Several lines of mice were characterized and shown to express the transgene at the mRNA and protein levels not only in the mammary gland but also in the salivary glands, epididymis, and prostate. In postpubertal virgin female mice, the expression of the EGFR-TR in the mammary glands was greater than the expression of the endogenous wild type EGFR. In these virgin mice, inhibition in mammary ductal development and a decrease of mammary epithelial DNA synthesis were observed beginning at 5-6 weeks. The inhibition of duct development was most apparent by 15-16 weeks, resulting in a significant defect in ductal branching and outgrowth and an apparent overall decrease in the size of the mammary glands. However, during pregnancy, expression of the endogenous wild type EGFR was markedly increased relative to the EGFR-TR and, at this stage, normal presecretory alveoli developed from the hypoplastic duct tree. Postpartum, normal lactation occurred. Despite EGFR-TR expression in other tissues, no morphological abnormalities were observed. This model demonstrates that the EGFR-TR behaves as a dominant negative regulator of the EGFR system in vivo and that the EGFR system plays an important role in mammary ductal development.
MeSH Terms
- Aging
- Animals
- DNA
- Epithelial Cells
- ErbB Receptors
- Female
- Gene Expression Regulation, Developmental
- Gene Targeting
- Genes, Dominant
- Mammary Glands, Animal
- Mammary Tumor Virus, Mouse
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Transgenes
Epidermal growth factor (EGF), EGF receptor (EGFR), and basic fibroblast growth factor (bFGF) messenger RNA (mRNA) levels were examined by Northern blot analysis in four tissues (pancreas, liver, kidney, and skeletal muscle) of pig from fetal 90 d to postnatal 180 d of age. The present study shows for the first time that EGF mRNA increased with advancing age in the kidney and skeletal muscle of pig. A high level of EGF mRNA was observed in the kidney compared with the liver and skeletal muscle. In the pancreas, high levels of EGF mRNA were found in fetuses and newborns and were low in older pigs. Pancreatic EGFR mRNA level parallelled its EGF mRNA, whereas in the kidney and skeletal muscle, patterns of EGFR mRNA were reversed to their EGF mRNA levels. In the liver, EGFR mRNA was abundant but EGF mRNA was undetected. In the pancreas and skeletal muscle, the highest levels of bFGF mRNA were found in fetuses of 90 d of age and then decreased with advancing age. In the liver and kidney, there were no major changes in bFGF mRNA levels during the examined developmental periods. These results show that EGF, EGFR, and bFGF mRNA levels are developmentally and tissue specifically regulated in pig. In the pancreas, mRNA levels of EGF, EGFR and bFGF were high in fetal and neonatal life and low thereafter. In the kidney and skeletal muscle, EGF mRNA increased with advancing age. EGF may play a role in muscle growth and maintenance in growing pigs during the later stage of development.
MeSH Terms
- Aging
- Animals
- Blotting, Northern
- Epidermal Growth Factor
- ErbB Receptors
- Female
- Fibroblast Growth Factor 2
- Kidney
- Liver
- Male
- Muscle Development
- Muscle, Skeletal
- Pancreas
- RNA, Messenger
- Swine
Although in Fischer-344 rats aging is found to be associated with increased gastric mucosal proliferative activity, little is known about the intracellular events that regulate this process. The present investigation examines the age-related changes in gastric mucosal tyrosine kinase activity and expression of epidermal growth factor receptor(EGFR) and its structural and functional analog p185c-erbB-2, the protein product of c-erbB-2/c-neu protooncogene. We observed a significantly higher intrinsic tyrosine kinase activity and tyrosine phosphorylation of EGFR and p185c-erbB-2 in the gastric mucosa of 24-mo-old (aged) rats than in that of their 4- or 12-mo-old counterparts. This was associated with increased levels of EGFR protein and steady-state mRNA levels of EGFR and p185c-erbB-2. In addition, we also observed threefold higher steady-state mRNA levels of transforming growth factor-alpha (TGF-alpha; one of the primary ligands of EGFR) in the gastric mucosa of aged rats than in that of 4-mo-old (young) animals. This was accompanied by a fivefold increase in the relative concentration of the 18-kDa precursor form of TGF-alpha in gastric mucosal membranes but not in the cytosol. In conclusion, our data demonstrate that aging is associated with increased tyrosine kinase activity of EGFR and p185c-erbB-2 in the gastric mucosa. Moreover, the observation that aging results in increased accumulation of TGF-alpha in gastric mucosal membranes raises the possibility that the membrane-bound TGF-alpha could partly be responsible for the constitutively active EGFR-induced signaling pathway in the gastric mucosa of aged rats and, in turn, for stimulation of mucosal proliferative activity.
MeSH Terms
- Aging
- Animals
- Blotting, Western
- ErbB Receptors
- Gastric Mucosa
- Male
- Phosphorylation
- Protein-Tyrosine Kinases
- RNA, Messenger
- Rats
- Rats, Inbred F344
- Receptor, ErbB-2
- Transforming Growth Factor alpha
Transgenic mice expressing either the neu proto-oncogene or transforming growth factor (TGF-alpha) in the mammary epithelium develop spontaneous focal mammary tumors that occur after a long latency. Since the epidermal growth factor receptor (EGFR) and Neu are capable of forming heterodimers that are responsive to EGFR ligands such as TGF-alpha, we examined whether coexpression of TGF-alpha and Neu in mammary epithelium could cooperate to accelerate the onset of mammary tumors. To test this hypothesis, we interbred separate transgenic strains harboring either a mouse mammary tumor virus/TGF-alpha or a mouse mammary tumor virus/neu transgene to generate bitransgenic mice that coexpress TGF-alpha and neu in the mammary epithelium. Female mice coexpressing TGF-alpha and neu developed multifocal mammary tumors which arose after a significantly shorter latency period than either parental strain alone. The development of these mammary tumors was correlated with the tyrosine phosphorylation of Neu and the recruitment of c-Src to the Neu complex. Immunoprecipitation and immunoblot analyses with EGFR- and Neu-specific antisera, however, failed to detect physical complexes of these two receptors. Taken together, these observations suggest that Neu and TGF-alpha cooperate in mammary tumorigenesis through a mechanism involving Neu and EGFR transactivation.
MeSH Terms
- Aging
- Animals
- Cell Transformation, Neoplastic
- Dimerization
- Epithelium
- Female
- Genes, erbB-2
- Mammary Glands, Animal
- Mammary Neoplasms, Experimental
- Mammary Tumor Virus, Mouse
- Mice
- Mice, Transgenic
- Phosphorylation
- Receptor, ErbB-2
- Transcription, Genetic
- Transforming Growth Factor alpha
Epidermal growth factor (EGF) binding increases in late-gestational rat kidney and then falls toward basal adult levels postnatally during the 1st wk. We report that the increase in EGF binding is accompanied by an increase in EGF receptor (EGFR) protein and activation of EGFR tyrosine kinase. Multiple proteins were endogenously tyrosine phosphorylated in kidney membranes from fetal rats, and the phosphorylation pattern was similar in rats ranging from 16 to 21 days of gestation. Tyrosine phosphorylation was, however, almost undetectable in 12-wk adult rat kidneys (controls). Among the phosphoproteins in fetal kidney, a prominent 170-kDa protein was identified as EGFR. Endogenous tyrosine phosphorylation of EGFR (reflecting receptor activation) was 30-fold higher in fetal kidney membranes than in adult (3- to 7-fold higher when adjusted for differences in EGF binding or EGFR protein content). The EGFR substrate, phospholipase C-gamma 1, was tyrosine phosphorylated in fetal kidneys but not adult, and a greater proportion was membrane-associated in fetal kidneys, consistent with activation of phospholipase C-gamma 1. Thus EGFR tyrosine kinase activity is increased in late-gestational rat kidney. Induction and activation of EGFR may mediate perinatal renal cell growth and development.
MeSH Terms
- Aging
- Animals
- Enzyme Activation
- ErbB Receptors
- Female
- Gestational Age
- Kidney
- Male
- Phosphorylation
- Protein-Tyrosine Kinases
- Rats
- Rats, Sprague-Dawley
- Type C Phospholipases
- Tyrosine
The postnatal rat small intestine undergoes major morphological, biochemical, and physiological changes during weaning. Phospholipase C-gamma 1 (PLC gamma 1), a tyrosine kinase substrate of the epidermal growth factor receptor (EGFR) hydrolyzes phosphatidylinositol-4,5-bisphosphate to products that may serve as mediators of growth and development. The aim of this study was to define developmental changes in intestinal PLC gamma 1 expression, catalytic activity, and growth factor regulation of PLC gamma 1. Immunodetection was used to compare the expression and tyrosine phosphorylation state of PLC gamma 1, EGFR, phosphatidylinositol 3-kinase (PI 3-kinase), ras guanosine triphosphatase activating protein (GAP), and src homologous collagen-like protein (SHC) in the postnatal rat intestine. The catalytic activity and expression of PLC gamma 1 markedly increased during weaning. Significant EGF-induced increases in the activity and tyrosine phosphorylation of PLC gamma 1 occurred in weanling but not suckling animals. EGFR and SHC expression were increased in weanling compared with suckling and adult animals; however, differences in expression of PI 3-kinase and GAP did not occur during weaning. The expression and catalytic activity of rat intestinal PLC gamma 1 are greatest during weaning. A functional consequence is the age-dependent modulation of EGF regulation of PLC gamma 1 tyrosine phosphorylation state and catalytic activity. This is the first in vivo demonstration of EGF-dependent tyrosine phosphorylation of PLC gamma 1 in normal animal tissue.
MeSH Terms
- Aging
- Animals
- Blotting, Western
- Epidermal Growth Factor
- ErbB Receptors
- GTPase-Activating Proteins
- Intestine, Small
- Phosphatidylinositol 3-Kinases
- Phosphorylation
- Phosphotransferases (Alcohol Group Acceptor)
- Precipitin Tests
- Proteins
- Rats
- Rats, Wistar
- Signal Transduction
- Type C Phospholipases
- Tyrosine
- Weaning
- ras GTPase-Activating Proteins
Patients with high-grade astrocytomas have a poor prognosis. However, considerable variation exists within this group of patients with respect to post-operative survival. In order to determine whether genetic alterations might be of help in subdividing this group, we used allele loss on chromosomes 10 and 17p and epidermal growth factor receptor (EGFR) gene amplification in the tumours as genetic parameters and determined their prognostic value. A series of 47 malignant (grade III and grade IV) tumours were genetically characterised, and four types of tumours were found. Type 1 tumours had loss of heterozygosity on chromosome arm 17p (LOH 17p) as the sole genetic alteration. Patients with this type of tumour were relatively young (mean age 39 years) and had a median survival period of 17 months. Type 2 tumours displayed only allele loss on chromosome 10 (LOH 10), type 3 tumours had LOH 10 LOH 17p and type 4 tumours contained LOH 10 EGFR gene amplification. Patients with types 2, 3 and 4 tumours were older (mean ages 59, 65 and 54 years respectively) and had a shorter survival (median duration 6, 3 and 2 months respectively) than type 1 patients. Multivariate analysis indicated that the genetic subdivision was a significant prognostic variable. In this study, age proved to be of minor importance with regard to survival. Our study revealed a predominance of frontally located tumours in patients with type 1 tumours, i.e. with LOH 17p only.
MeSH Terms
- Adult
- Aged
- Aging
- Alleles
- Astrocytoma
- Brain Neoplasms
- Chromosomes, Human, Pair 10
- Chromosomes, Human, Pair 17
- ErbB Receptors
- Female
- Gene Amplification
- Gene Deletion
- Heterozygote
- Humans
- Male
- Middle Aged
- Multivariate Analysis
- Prognosis
- Survival Analysis
This study was designed to localize transforming growth factor alpha (TGF-alpha) and epidermal growth factor receptor (EGFR) expression in the developing human gastrointestinal tract and pancreas. Immunohistochemical techniques using specific antibodies against human TGF-alpha and EGFR were performed on digestive tissues of fetuses from 9 to 10 to 24 weeks of gestation, children and adults. In fetuses, TGF-alpha and EGFR proteins were expressed in all epithelial tissues studied with a good correlation and from an age as early as 9 to 10 weeks of gestation, except for TGF-alpha in the esophagus. The strongest TGF-alpha immunostaining was noted in the stomach and the proximal colon. Unexpectedly, immunoreactive gut endocrine cells were observed with the two antibodies used. Relatively numerous in fetuses, they decreased in number with age and were rare in adults particularly along the colon. Enteroglucagonsecreting cells were shown to express TGF-alpha, while some gastrin, somatostatin and pancreatic glucagon cells were immunostained with EGFR antibodies. The presence of TGF-alpha and its receptor in digestive tract epithelium and pancreatic tissues early in fetal life suggests a functional role for TGF-alpha during the developmental process of the digestive system. We demonstrate that TGF-alpha is also produced by endocrine cells and might have an additional mode of action other than paracrine, at least during fetal life.
MeSH Terms
- Adult
- Aging
- Child, Preschool
- Digestive System
- Embryonic and Fetal Development
- ErbB Receptors
- Female
- Humans
- Immunohistochemistry
- Infant
- Pancreas
- Pregnancy
- Transforming Growth Factor alpha
In rat brain, distinct epidermal growth factor-receptor immunoreactivity (EGFR-IR) first appeared in astroglia at about day 16 postnatal, reached maximum intensity at 19 days and then became much weaker as the animals reached adulthood. EGFR-IR was also observed in cerebellar Purkinje cells as early as 11 days postnatal and was maintained into adulthood. In adult and aged animals the most prominent EGF receptor immunostaining occurred in cerebral cortex neurons (layers IV and V) that had the morphology of basket cells. Immunoreactive neurons were abundant in the cingulate, frontal, frontoparietal and striate cortices. In the frontoparietal cortex, EGFR positive neurons were most numerous in the motor area, diminishing laterally towards the somatosensory area. The localization and time of appearance of EGFR-IR did not appear consistent with a direct mitogenic role of the EGF domain in astroglia proliferation during development. However, the EGFR may be involved in neuronal survival and/or neuron-glia signalling.
MeSH Terms
- Aging
- Antibodies, Monoclonal
- Astrocytes
- Brain
- Cerebral Cortex
- ErbB Receptors
- Immunohistochemistry
- Purkinje Cells
Brain astroglia in normal adult rats stained weakly or not at all with an antibody to epidermal growth factor receptor (EGFR). A dramatic change took place after injury. The astrocytes adjacent to an entorhinal ablation and in deafferented areas of the hippocampus showed prominent EGFR immunoreactivity. Cells that were EFGR-immunoreactive also stained intensely with an antibody to glial fibrillary acidic protein (GFAP). The localization and the time course of appearance of EGFR/GFAP immunoreactivity suggests that EGFR may be involved in the conversion of a normal into a reactive astrocyte.
MeSH Terms
- Aging
- Animals
- Astrocytes
- Brain Injuries
- Cerebral Cortex
- ErbB Receptors
- Glial Fibrillary Acidic Protein
- Male
- Rats
- Rats, Inbred Strains
Immunoreactivity to epidermal growth factor receptor (EGFR) was present in the brain vasculature of 13/13 demented elderly patients, but absent in 9/11 non-demented elderly patients. Of the two positive non-demented patients, one had significant Alzheimer's pathology and the other spinal carcinoma. Ultrastructurally, EGFR is localized to the lumenal surface of endothelial cells.
MeSH Terms
- Aged
- Aged, 80 and over
- Aging
- Brain
- Dementia
- Endothelium, Vascular
- ErbB Receptors
- Female
- Humans
- Immunohistochemistry
- Male
- Middle Aged
Epidermal growth factor receptors (EGFR) and transferrin receptors (TFR) are known to be involved in cell proliferation and to be expressed in normal human epidermis. To date little is known about EGFR and TRF expression in human skin during embryonic and fetal development. In the present work, we studied skin specimens from 30 aborted embryos and fetuses ranging from 7 to 31 weeks estimated gestational age. Monoclonal antibodies to EGFR and TFR were applied on frozen skin sections using an amplification biotin-streptavidin-fluorescein technique. TFR was faintly expressed on epidermal basal cells throughout embryonic and fetal development, as it is in adult epidermis. Up to week 12, EGFR was uniformly expressed on cells of the basal, intermediate and periderm cell layers. From the midfetal period onwards, the suprabasal cell layers showed a decreased staining compared with the basal layer. During the third trimester the cornified cell layer was completely negative. The hair germ and heir peg cells were positive. Later, the outer root sheath and hair bulb remained labelled, with less staining of the hair cone. The sebaceous and eccrine sweat glands were also labelled. These results suggest that in embryonic and fetal epidermis, TFR expression is not correlated with cellular proliferation, whereas EGFR appear to be associated with proliferating and undifferentiated cells.
MeSH Terms
- Adult
- Aging
- Epidermis
- ErbB Receptors
- Fetal Proteins
- Fluorescent Antibody Technique
- Humans
- Receptors, Transferrin
Changes in the expression rate of epidermal growth factor receptor (EGFR) mRNA with age in the liver of rats were examined to assess the contribution of EGF to the proliferation of hepatocytes in younger animals. Northern blot analyses with a 32P-labeled probe derived from the extracellular domain of EGFR cDNA were evaluated quantitatively by normalizing the densitometric scanning data with the relative amounts of poly(A) RNA in the samples. The expression of EGFR mRNA was low during the early period and increased towards the adult level after 21 days of birth. In contrast, the rate of beta-actin mRNA expression was significantly higher immediately after birth and showed a tendency to decrease with time.
MeSH Terms
- Actins
- Aging
- Animals
- Blotting, Northern
- Densitometry
- ErbB Receptors
- Liver
- Poly A
- RNA
- RNA, Messenger
- Rats
- Rats, Wistar