TP53
Cellular tumor antigen p53 (Antigen NY-CO-13) (Phosphoprotein p53) (Tumor suppressor p53) [P53]
Publications[править]
Late-onset asthma (LOA) is beginning to account for an increasing proportion of asthma patients, which is often underdiagnosed in the elderly. Studies on the possible relations between aging-related genes and LOA contribute to the diagnosis and treatment of LOA. Forkhead Box O3 (FOXO3) and TP53 are two classic aging-related genes. DNA methylation varies greatly with age which may play an important role in the pathogenesis of LOA. We supposed that the differentially methylated sites of FOXO3 and TP53 associated with clinical phenotypes of LOA may be useful biomarkers for the early screening of LOA. The mRNA expression and DNA methylation of FOXO3 and TP53 in peripheral blood of 43 LOA patients (15 mild LOA, 15 moderate LOA and 13 severe LOA) and 60 healthy controls (HCs) were determined. The association of methylated sites with age was assessed by Cox regression to control the potential confounders. Then, the correlation between differentially methylated sites (DMSs; p-value < 0.05) and clinical lung function in LOA patients was evaluated. Next, candidate DMSs combining with age were evaluated to predict LOA by receiver operating characteristic (ROC) analysis and principal components analysis (PCA). Finally, HDM-stressed asthma model was constructed, and DNA methylation inhibitor 5-Aza-2'-deoxycytidine (5-AZA) were used to determine the regulation of DNA methylation on the expression of FOXO3 and TP53. Compared with HCs, the mRNA expression and DNA methylation of FOXO3 and TP53 vary significantly in LOA patients. Besides, 8 DMSs from LOA patients were identified. Two of the DMSs, chr6:108882977 (FOXO3) and chr17:7591672 (TP53), were associated with the severity of LOA. The combination of the two DMSs and age could predict LOA with high accuracy (AUC values = 0.924). In HDM-stressed asthma model, DNA demethylation increased the expression of FOXO3 and P53. The mRNA expression of FOXO3 and TP53 varies significantly in peripheral blood of LOA patients, which may be due to the regulation of DNA methylation. FOXO3 and TP53 methylation is a suitable blood biomarker to predict LOA, which may be useful targets for the risk diagnosis and clinical management of LOA.
Keywords
- Aging
- DNA methylation
- FOXO3
- Late-onset asthma
- TP53
Periodontal ligament stem cells (PDLSCs) have many applications in the field of cytotherapy, tissue engineering, and regenerative medicine. However, the effect of age on the biological and immunological characteristics of PDLSCs remains unclear. In this study, we compared PDLSCs isolated from young and adult individuals. PDLSC proliferation was analyzed by Cell Counting Kit-8 (CCK-8) and 5-ethynyl-2'-deoxyuridine (EdU) staining, and apoptosis level was detected by Annexin V-PE/7-ADD staining. PDLSC osteogenic/adipogenic/chondrogenic differentiation potentials were assessed by alkaline phosphatase (ALP), Alizarin Red, Oil Red O, Alcian Blue staining, and related quantitative analysis. PDLSC immunosuppressive capacity was determined by EdU and Annexin V-PE/7-ADD staining. To explore its underlying mechanism, microarray, quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR), and western blot analyses were performed to detect differentially expressed genes and proteins in PDLSCs. Our results demonstrated that with aging, the proliferation and osteogenic/adipogenic/chondrogenic differentiation potential of PDLSCs decreased, whereas apoptosis of PDLSCs increased. Moreover, the immunosuppressive ability of PDLSCs decreased with aging. Compared with PDLSCs from young subjects, analysis of mRNA expression revealed an upregulation of CCND3 and RC3H2, and a downregulation of Runx2, ALP, COL1A1, PPARγ2, CXCL12, FKBP1A, FKBP1B, NCSTN, P2RX7, PPP3CB, RIPK2, SLC11A1, and TP53 in those from adult individuals. Furthermore, protein expression levels of Runx2, ALP, COL1A1, and PPARγ2 in the adult group were decreased, whereas that of CCND3 increased. Taken together, aging influences the biological and immunological characteristics of PDLSCs, and thus, it is more appropriate to utilize PDLSCs from young individuals for tissue regeneration, post-aging treatment, and allotransplantation.
Keywords
- Aging
- Immunosuppression
- Osteogenic differentiation
- Periodontal ligament stem cells
- Peripheral blood mononuclear cells
- Tissue engineering
Ovarian aging affects female reproductive potential and is characterized by alterations in proteins, mRNAs and non-coding RNAs inside the ovarian follicle. Ovarian somatic cells and the oocyte communicate with each other secreting different molecules into the follicular fluid, by extracellular vesicles. The cargo of follicular fluid vesicles may influence female reproductive ability; accordingly, analysis of extracellular vesicle content could provide information about the quality of the female germ cell.In order to identify the most significant deregulated microRNAs in reproductive aging, we quantified the small extracellular vesicles in human follicular fluid from older and younger women and analyzed the expression of microRNAs enclosed inside the vesicles. We found twice as many small extracellular vesicles in the follicular fluid from older women and several differentially expressed microRNAs. Correlating microRNA expression profiles with vesicle number, we selected 46 deregulated microRNAs associated with aging. Bioinformatic analyses allowed us to identify six miRNAs involved in TP53 signaling pathways. Specifically, miR-16-5p, miR214-3p and miR-449a were downregulated and miR-125b, miR-155-5p and miR-372 were upregulated, influencing vesicle release, oocyte maturation and stress response. We believe that this approach allowed us to identify a battery of microRNAs strictly related to female reproductive aging.
Keywords
- extracellular vesicles
- follicular fluid
- microRNAs
- reproductive aging
Replicative senescence causes a reduced osteogenic differentiation potential of senescent dental follicle cells (DFCs). The transcription factor p53 is often involved in the induction of cellular senescence, but little is known about its role in DFCs. This study examined for the first time the role of p53 compared to its pro-proliferative antagonist E2F-1 in terms of osteogenic differentiation potential and induction of senescence. Protein expression of E2F-1 decreased during cell aging, while p53 was expressed constitutively. Gene silencing of E2F1 (E2F-1) inhibited the proliferation rate of DFCs and increased the induction of cellular senescence. The induction of cellular senescence is regulated independently of the gene expression of TP53 (p53), since its gene expression depends on the expression of E2F1. Moreover, gene silencing of TP53 induced E2F1 gene expression and increased cell proliferation, but did not affect the rate of induction of cellular senescence. TP53 knockdown further induced the alkaline phosphatase and mineralization in DFCs. However, the simultaneous silencing of TP53 and E2F1 did not inhibit the inductive effect of TP53 knockdown on osteogenic differentiation, indicating that this effect is independent of E2F-1. In summary, our results suggest that p53 inhibits osteogenic differentiation and cell proliferation in senescent DFCs, but is not significantly involved in senescence induction.
Keywords
- Cellular senescence
- Dental follicle cells
- E2F-1
- Osteogenic differentiation
- p53
The improved effectiveness and safety of the combined antiretroviral therapy (cART) has largely diminished mortality and AIDS-defining morbidity of HIV-patients. Nevertheless, chronic age-related diseases in these individuals are more common and their underlying pathogenic mechanisms of these actions seem to involve accelerated aging and enhanced inflammation. The present study explores markers of these processes in a heterogenous Spanish HIV cohort using peripheral blood samples of HIV-patients and matched uninfected controls. We isolated periheral blood mononuclear cells (PBMCs) and i) compared the expression of a panel of 14 genes related to inflammation and senescence in PBMCs of HIV-patients vs matched uninfected controls, ii) analyzed the expression in HIV-patients in association with a number of demographic, biochemical and immunological parameters and iii) in relation with the current cART they received. PBMCs of HIV-patients displayed significantly increased expression of general inflammatory genes (IL6, IL18 and CXCL10) and this occurs irrespectively of the antiviral therapy they have been receiving. Conversely, levels of senescence-associated genes TP53, SERPINE1andIGFBP3 were slightly but significantly reduced in patients compared to uninfected matched individuals and this effect is related to NNRTI-containing treatments. The expression of the inflammatory markers IL6, IL18, IL1B, TNFA, RELA, CCL2, [[CCL20]] and CXCL10 displayed correlation with certain demographic, morbidity- and HIV infection-related parameters. The levels of TP53 mRNA were positively associated only with plasma LDL. Correlation analysis between the expressions of pairs of genes revealed a different pattern between HIV-patients and controls. The diminished expression of TP53 and SERPINE1 in HIV-patients was also observed at a protein level, and the correlation between the two proteins (p53 and PAI1) in patients and controls showed the opposite trend. In conclusion, HIV-patients show dysregulation of p53 and p53-related mediators, a phenomenon which may be of pathophysiological relevance and could be related to the shorter health- and/or life-span observed in these individuals.
Keywords
- Aging
- Antiretroviral drugs
- HIV
- Inflammation
- NNRTI
- Senescence
- p53
Anemia is a major and currently poorly understood clinical manifestation of hematopoietic aging. Upon aging, hematopoietic clones harboring acquired leukemia-associated mutations expand and become detectable, now referred to as clonal hematopoiesis (CH). To investigate the relationship between CH and anemia of the elderly, we explored the landscape and dynamics of CH in older individuals with anemia. From the prospective, population-based Lifelines cohort (n = 167 729), we selected all individuals at least 60 years old who have anemia according to World Health Organization criteria (n = 676) and 1:1 matched control participants. Peripheral blood of 1298 individuals was analyzed for acquired mutations at a variant allele frequency (VAF) of 1% or higher in 27 driver genes. To track clonal evolution over time, we included all available follow-up samples (n = 943). CH was more frequently detected in individuals with anemia (46.6%) compared with control individuals (39.1%; P = .007). Although no differences were observed regarding commonly detected DTA mutations (DNMT3A, TET2, ASXL1) in individuals with anemia compared with control individuals, other mutations were enriched in the anemia cohort, including TP53 and SF3B1. Unlike individuals with nutrient deficiency (P = .84), individuals with anemia of chronic inflammation and unexplained anemia revealed a higher prevalence of CH (P = .035 and P = .017, respectively) compared with their matched control individuals. Follow-up analyses revealed that clones may expand and decline, generally showing only a subtle increase in VAF (mean, 0.56%) over the course of 44 months, irrespective of the presence of anemia. Specific mutations were associated with different growth rates and propensities to acquire an additional hit. In contrast to smaller clones (<5% VAF), which did not affect overall survival, larger clones were associated with increased risk for death.
MeSH Terms
- Age Factors
- Aged
- Aging
- Anemia
- Female
- Hematopoiesis
- Humans
- Kaplan-Meier Estimate
- Male
- Middle Aged
- Mutation
- Prospective Studies
Pancreatic ductal adenocarcinoma (PDAC) is a disease of aging. The [i]TP53[/i] gene product regulates cell growth, aging, and cancer. To determine the important targets of TP53 in PDAC, we examined the expression of 440 proteins on a reverse phase protein array (RPPA) in PDAC-derived MIA-PaCa-2 cells which either had WT-[i]TP53[/i] or lacked WT-[i]TP53[/i]. MIA-PaCa-2 cells have a [i]TP53[/i] mutation as well as mutant [i]KRAS[/i] and represent a good [i]in vitro[/i] model to study PDAC. RPPA analysis demonstrated expression of tumor promoting proteins in cells that lacked WT-[i]TP53[/i]; and this feature could be reversed significantly when the cells were transfected with vector encoding WT-[i]TP53[/i] or treated with berberine or a modified berberine (BBR). Expression of miR-34a-associated signaling was elevated in cells expressing WT-[i]TP53[/i] compared to cells expressing [i]mTP53[/i]. Results from [i]in vivo[/i] studies using human PDAC specimens confirmed the [i]in vitro[/i] results as the expression of miR-34a and associated signaling was significantly decreased in PDAC specimens compared to non-cancerous tissues. This study determined [i]SERPINE1[/i] as a miR-34a target with relevance to the biology of PDAC. Thus, we have identified a key target ([i]SERPINE1[/i]) of the TP53/miR-34a axis that may serve as a potential biomarker for early detection of pancreatic cancer.
Keywords
- Aging
- PDAC
- SERPINE1
- TP53
- cancer
- miR-34a
Nodular fasciitis (NF) is a self-limited tumorous lesion occurring in the upper as well as lower extremities. NF is composed of a proliferation of "primary culture"-like myofibroblastic cells with nuclear atypia and large nucleoli, thus mimicking sarcoma. NF harbors a promoter-swapping fusion gene containing the entire coding region of [i]USP6[/i] gene. Therefore, NF is a tumor with a fusion oncogene but self-limited. In order to explore why NF is self-limited, we examined whether myofibroblastic cells in NF express p16 protein, a gene product of [i]CDKN2A[/i] gene and an inhibitor of cyclin-dependent kinase 4 (CDK4) as well as one of the hallmarks of cellular senescence. We immunohistochemically demonstrated strong and diffuse expression of p16 in myofibroblastic cells in 11 out of 15 cases of NF, and strong but partial expression in the remaining 4 of the cases. We also showed that 15 out of 15 cases of NF were immunohistochemically negative or only showed focal and faint immunopositivity for CDK4, murine double minute 2 (MDM2), and TP53 proteins. Furthermore, there were no significant changes in the copy number of [i]CDKN2A, CDK4[/i] and [i]MDM2[/i] genes, and no significant mutations in [i]TP53, RB1,[/i] and [i]CDKN2A[/i] genes in 1 case of NF selected. These data suggest a possible involvement in cell cycle arrest and presumed cellular senescence by p16 in myofibroblastic cells in NF. This may explain the self-limited as well as inflammatory nature of NF as a senescence-associated secretory phenotype.
Keywords
- CDK4
- MDM2
- TP53
- nodular fasciitis
- p16
- senescence
Preclinical experiments and clinical trials demonstrated that angiotensin II AT receptor overactivity associates with aging and cellular senescence and that AT receptor blockers (ARBs) protect from age-related brain disorders. In a primary neuronal culture submitted to glutamate excitotoxicity, gene set enrichment analysis (GSEA) revealed expression of several hundred genes altered by glutamate and normalized by candesartan correlated with changes in expression in Alzheimer's patient's hippocampus. To further establish whether our data correlated with gene expression alterations associated with aging and senescence, we compared our global transcriptional data with additional published datasets, including alterations in gene expression in the neocortex and cerebellum of old mice, human frontal cortex after age of 40, gene alterations in the Werner syndrome, rodent caloric restriction, Ras and oncogene-induced senescence in fibroblasts, and to tissues besides the brain such as the muscle and kidney. The most significant and enriched pathways associated with aging and senescence were positively correlated with alterations in gene expression in glutamate-injured neurons and, conversely, negatively correlated when the injured neurons were treated with candesartan. Our results involve multiple genes and pathways, including CAV1, CCND1, CDKN1A, CHEK1, ICAM1, IL-1B, IL-6, MAPK14, PTGS2, SERPINE1, and TP53, encoding proteins associated with aging and senescence hallmarks, such as inflammation, oxidative stress, cell cycle and mitochondrial function alterations, insulin resistance, genomic instability including telomere shortening and DNA damage, and the senescent-associated secretory phenotype. Our results demonstrate that AT receptor blockade ameliorates central mechanisms of aging and senescence. Using ARBs for prevention and treatment of age-related disorders has important translational value.
Keywords
- Aging
- Angiotensin receptor blockers
- Glutamate excitotoxicity
- Senescence
- p53 neuroprotection
Human diploid fibroblasts (HDFs) cultured in vitro have limited capacity to proliferate after population doubling is repeated several times, and they enter into a state known as replicative senescence or cellular senescence. This study aimed to investigate the effect of Chlorella vulgaris on the replicative senescence of HDFs by determining the expression of senescence-associated genes. Young and senescent HDFs were divided into untreated control and C. vulgaris-treated groups. A senescence-associated gene transcription analysis was carried out with qRT-PCR. Treatment of young HDFs with C. vulgaris reduced the expression of SOD1, CAT and CCS (p < 0.05). In addition, the expression of the SOD2 gene was increased with C. vulgaris treatment in young, pre-senescent and senescent HDFs (p < 0.05). Treatment of senescent HDFs with C. vulgaris resulted in the downregulation of TP53 gene expression. The expression of the [[CDKN2A]] gene was significantly decreased upon C. vulgaris treatment in young and senescent HDFs. C. vulgaris treatment was also found to significantly upregulate the expression of the MAPK14 gene in pre-senescent HDFs. In addition, the expression of MAPK14 was significantly upregulated compared to that in the untreated senescent HDFs (p < 0.05). In summary, the expression of senescence-associated genes related to antioxidants and the insulin/insulin-like growth factor-1 signalling, DNA damage-associated signalling, cell differentiation and cell proliferation pathways was modulated by C. vulgaris during replicative senescence of human diploid fibroblasts.
MeSH Terms
- Antioxidants
- Catalase
- Cell Differentiation
- Cell Proliferation
- Cells, Cultured
- Cellular Senescence
- Chlorella vulgaris
- DNA Damage
- Diploidy
- Fibroblasts
- Gene Expression
- Genes, p53
- Humans
- Male
- Mitogen-Activated Protein Kinase 14
- Molecular Chaperones
- Primary Cell Culture
- Signal Transduction
- Superoxide Dismutase
- Superoxide Dismutase-1
Keywords
- Chlorella vulgaris
- Fibroblasts
- Replicative senescence
- Senescence-associated genes
Functional and quantitative alterations and senescence of circulating and expanded endothelial progenitor cells (EPC), as well as systemic and tissue modifications of angiogenetic and inflammatory molecules, were evaluated for predicting age-related vessel wall remodeling, correlating them to intima media thickness (IMT) in the common carotid artery (CCA), a biomarker of early cardiovascular disease and aortic root dilation. A homogenous Caucasian population was included in the study, constituted by 160 healthy subjects (80 old subjects, mean age 72 ± 6.4, range 66-83 years; and 80 younger blood donors, mean age 26.2 ± 3.4, range 21-33 years), and 60 old subjects (mean age 73 ± 1.4 (range 66-83) years) with aortic root dilatation and hypertension, and 60 old people (70 ± 2.8 (age range 66-83)) with sporadic ascending aorta aneurysm (AAA). In addition, 20 control individuals (10 men and 10 women, mean age: 65 ± 8), were also included in the study for evaluating the gene expression's levels, in aorta tissues. Appropriate techniques, practises, protocols, gating strategies and statistical analyses were performed in our evaluations. Interestingly, old people had a significantly reduced functionality and a high grade of senescence (high SA-β-Gal activity and high levels of TP53, p21 and p16 genes) of EPC expanded than younger subjects. The values of related parameters progressively augmented from the old subjects, in good healthy shape, to subjects with hypertension and aorta dilation, and AAA. Moreover, they significantly impacted the endothelium than the alterations in EPC number. No changes, but rather increased systemic levels of VEGF and SDF-1 were also assessed in old people vs. younger donors. Old people also showed significantly increased systemic levels of inflammatory cytokines, and a reciprocal significant reduction of systemic s-Notch 1 than younger subjects. These parameters, also including the number EPC alterations, resulted to be significantly sustained in old people bearers of an inflammatory combined genotype. Consistent with these data, a reduced expression of Notch-1 gene, accompanied by a sustained expression of inflammatory genes (i.e. TLR4, IL-1β, IL-6 and IL-17) were detected in aortic tissues from old control people and AAA cases. Finally, we detected the biological effects induced by all the detected alterations on vessel wall age-related remodeling, by evaluating the IMT in the population studied and correlating it to these alterations. The analysis demonstrated that the unique independent risk predictors for vascular ageing are age, the EPC reduced migratory activity and senescence, high grade of expression of genes inducing EPC senescence and chronic tissue and systemic inflammation. Thus, we propose these parameters, of easy determination in biological samples (i.e. blood and tissue samples) from alive human population, as optimal biomarkers for vascular ageing.
MeSH Terms
- Adult
- Aged
- Aged, 80 and over
- Aging
- Aorta
- Biomarkers
- Carotid Artery, Common
- Carotid Intima-Media Thickness
- Chemokine CXCL12
- Chemotaxis
- Endothelial Progenitor Cells
- Female
- Humans
- Male
- Receptor, Notch1
- Toll-Like Receptor 4
- Vascular Endothelial Growth Factor A
- Young Adult
Keywords
- EPC cell populations
- Endothelium age-related impairment
- Inflammatory cytokines
- Notch and TLR4
- SA-β-Gal activity
- TP53, p21 and p16 genes
High-accuracy next-generation DNA sequencing promises a paradigm shift in early cancer detection by enabling the identification of mutant cancer molecules in minimally invasive body fluid samples. We demonstrate 80% sensitivity for ovarian cancer detection using ultra-accurate Duplex Sequencing to identify TP53 mutations in uterine lavage. However, in addition to tumor DNA, we also detect low-frequency TP53 mutations in nearly all lavages from women with and without cancer. These mutations increase with age and share the selection traits of clonal TP53 mutations commonly found in human tumors. We show that low-frequency TP53 mutations exist in multiple healthy tissues, from newborn to centenarian, and progressively increase in abundance and pathogenicity with older age across tissue types. Our results illustrate that subclonal cancer evolutionary processes are a ubiquitous part of normal human aging, and great care must be taken to distinguish tumor-derived from age-associated mutations in high-sensitivity clinical cancer diagnostics.
MeSH Terms
- Adult
- Aged
- Aged, 80 and over
- Aging
- Cell-Free Nucleic Acids
- Clonal Evolution
- DNA, Neoplasm
- Databases, Genetic
- Female
- High-Throughput Nucleotide Sequencing
- Humans
- Infant, Newborn
- Middle Aged
- Mutation
- Ovarian Neoplasms
- Selection, Genetic
- Sequence Analysis, DNA
- Tumor Suppressor Protein p53
- Uterus
Keywords
- Duplex Sequencing
- TP53, clonal evolution
- aging
- early detection
- gynecologic oncology
- high-grade serous ovarian cancer
- next-generation sequencing
- somatic mutations
- uterine lavage
MYC and RUNX oncogenes each trigger p53-mediated failsafe responses when overexpressed in vitro and collaborate with p53 deficiency in vivo. However, together they drive rapid onset lymphoma without mutational loss of p53. This phenomenon was investigated further by transcriptomic analysis of premalignant thymus from RUNX2/MYC transgenic mice. The distinctive contributions of MYC and RUNX to transcriptional control were illustrated by differential enrichment of canonical binding sites and gene ontology analyses. Pathway analysis revealed signatures of MYC, CD3, and CD28 regulation indicative of activation and proliferation, but also strong inhibition of cell death pathways. In silico analysis of discordantly expressed genes revealed Tnfsrf8/CD30, Cish, and Il13 among relevant targets for sustained proliferation and survival. Although TP53 mRNA and protein levels were upregulated, its downstream targets in growth suppression and apoptosis were largely unperturbed. Analysis of genes encoding p53 posttranslational modifiers showed significant upregulation of three genes, Smyd2, Set, and Prmt5. Overexpression of SMYD2 was validated in vivo but the functional analysis was constrained by in vitro loss of p53 in RUNX2/MYC lymphoma cell lines. However, an early role is suggested by the ability of SMYD2 to block senescence-like growth arrest induced by RUNX overexpression in primary fibroblasts.
MeSH Terms
- Animals
- Blotting, Western
- Cell Line, Tumor
- Cell Proliferation
- Cellular Senescence
- Computational Biology
- Core Binding Factor Alpha 1 Subunit
- Histone-Lysine N-Methyltransferase
- Lymphoma
- Mice
- Mice, Transgenic
- Principal Component Analysis
- Proto-Oncogene Proteins c-myc
- Receptors, Antigen, T-Cell
- Signal Transduction
- Thymus Gland
- Tumor Suppressor Protein p53
Keywords
- MYC
- RUNX
- SMYD2
- lymphoma
- p53
- senescence
Understanding how age affects fertility becomes increasingly relevant as couples delay childbearing toward later stages of their lives. While the influence of maternal age on fertility is well established, the impact of paternal age is poorly characterized. Thus, this study aimed to understand the molecular mechanisms responsible for age-dependent decline in spermatozoa quality. To attain it, we evaluated the impact of male age on the activity of signaling proteins in two distinct spermatozoa populations: total spermatozoa fraction and highly motile/viable fraction. In older men, we observed an inhibition of the mechanistic target of rapamycin complex 1 (mTORC1) in the highly viable spermatozoa population. On the contrary, when considering the entire spermatozoa population (including defective/immotile/apoptotic cells) our findings support an active mTORC1 signaling pathway in older men. Additionally, total spermatozoa fractions of older men presented increased levels of apoptotic/stress markers (e.g., cellular tumor antigen p53-TP53) and mitogen-activated protein kinases (MAPKs) activity. Moreover, we established that the levels of most signaling proteins analyzed were consistently and significantly altered in men more than 27 years of age. This study was the first to associate the mTOR signaling pathway with the age impact on spermatozoa quality. Additionally, we constructed a network of the sperm proteins associated with male aging, identifying TP53 as a central player in spermatozoa aging.
MeSH Terms
- Aged
- Humans
- Male
- Models, Biological
- Protein Interaction Maps
- Signal Transduction
- Spermatozoa
- TOR Serine-Threonine Kinases
Keywords
- TP53
- aging
- mTORC1
- signaling proteins
- sperm quality
The insulin-like growth factor 1 (IGF1) signaling pathway as an aging mechanism related to p53 in human melanogenesis remains unclear. The aim of this study was to investigate the relationship between p53 and IGF1 signaling pathway in young, senescent and H O -treated cells. The protein and gene expression in young, senescent and H O -treated cells were analyzed using western blot and reverse transcription polymerase chain reaction (RT-PCR) assays, respectively. The expression levels of (phosphoinositide 3-kinases) PI3K, v-akt murine thymoma viral oncogene homolog 1 (AKT1), mammalian target of rapamycin, β-catenin (CTNNB1), acetylated p53 (ac-p53), p53 and p-p21 proteins, related to IGF1 and p53 signaling pathways, were higher in senescent and H O -treated cells than those of young cells. Furthermore, AKT reduced melanogenesis through microphthalmia-associated transcription factor (MITF) inactivation by the inhibition of CTNNB1. The gene expression levels of PI3K, TP53 and catalase (CAT) in senescent and H O -treated cells were increased compared to young cells. p53 protein plays a key role in the aging of melanocytes via IGF1 signaling pathways.
MeSH Terms
- Aging
- Animals
- Catalase
- Cell Proliferation
- Cellular Senescence
- Gene Expression Regulation
- Humans
- Hydrogen Peroxide
- Insulin-Like Growth Factor I
- Melanocytes
- Mice
- Microphthalmia-Associated Transcription Factor
- Phosphatidylinositol 3-Kinases
- Proto-Oncogene Proteins c-akt
- Signal Transduction
- Tumor Suppressor Protein p53
- beta Catenin
Keywords
- AKT1
- H2O2
- IGF1
- PI3K
- melanocyte
- p53
Replication stress (RS) is a major driver of genomic instability and tumorigenesis. Here, we investigated whether RS induced by the nucleotide analog fludarabine and specific kinase inhibitors [e.g. targeting checkpoint kinase 1 (Chk1) or ataxia telangiectasia and Rad3-related (ATR)] led to apoptosis or senescence in four cancer cell lines differing in TP53 mutation status and expression of lamin A/C (LA/C). RS resulted in uneven chromatin condensation in all cell types, as evidenced by the presence of metaphasic chromosomes with unrepaired DNA damage, as well as detection of less condensed chromatin in the same nucleus, frequent ultrafine anaphase bridges, and micronuclei. We observed that responses to these chromatin changes may be distinct in individual cell types, suggesting that expression of lamin A/C and lamin B1 (LB1) may play an important role in the transition of damaged cells to senescence. MCF7 mammary carcinoma cells harboring wild-type p53 (WT-p53) and LA/C responded to RS by transition to senescence with a significant reduction of lamin B receptor and LB1 proteins. In contrast, a lymphoid cancer cell line WSU-NHL (WT-p53) lacking LA/C and expressing low levels of LB1 died after several hours, while lines MEC-1 and SU-DHL-4, both with mutated p53, and SU-DHL-4 with mutations in LA/C, died at different rates by apoptosis. Our results show that, in addition to being influenced by p53 mutation status, the response to RS (apoptosis or senescence) may also be influenced by lamin A/C and LB1 status.
MeSH Terms
- Apoptosis
- Cell Line, Tumor
- Cellular Senescence
- DNA Replication
- Humans
- Lamin Type A
- MCF-7 Cells
- Mutation
- Tumor Suppressor Protein p53
- Vidarabine
Keywords
- ATR inhibitor
- Chk1 inhibitor
- apoptosis
- lamin B receptor
- replication stress
- senescence
Lung adenocarcinoma (LUAD) is the most common cause of global cancer-related mortality and the major risk factor is smoking consumption. By analyzing 486 LUAD samples from The Cancer Genome Atlas, we detected a higher mutational burden among younger patients in the global cohort as well as in the TP53-mutated subcohort. The interaction effect of patient age and TP53 mutations significantly affected the mutational rate of younger TP53-mutated patients. Furthermore, we detected a significant enrichment of the smoking-related signature SI4 (SI4) among younger TP53-mutated patients, meanwhile the age-related Signature 1 (SI1) significantly increased in proportion to patient age. Although present and past smoking is reported in the TP53 wild-type patients, we observed a lower average number of somatic mutations, with no correlation with patient age. Overall, TP53 mutations were significantly higher in younger patients and mainly characterized by SI4 and Signature 24 (SI24). Therefore, TP53 seemed to acquire a particular sensitivity to smoking related C>A mutations in younger patients. We hypothesize that TP53 mutations at a younger age might be a crucial factor enhancing the sensitivity to smoking-related mutations leading to a burst of somatic alterations. The mutational profile of cancer cell might reflect the mutational processes operative in aging in a given tissue. Therefore, TP53-mutated and TP53 wild-type patient groups might represent phenotypes which endure aging-related mutational processes with different strength. Our study provides indications of age-dependent differences in mutational backgrounds that might be relevant for cancer prevention and age-adjusted treatment approaches.
MeSH Terms
- Adenocarcinoma of Lung
- Adult
- Age Factors
- Aged
- Aged, 80 and over
- Cohort Studies
- Female
- Humans
- Lung Neoplasms
- Male
- Middle Aged
- Mutation
- Smoking
- Tumor Suppressor Protein p53
Keywords
TP53
- CNAs
- aging
- mutational patterns
- somatic mutations
Renal clear cell carcinoma (RCC) is the most common type of kidney cancer and has a high propensity for metastasis. While treatment with immune checkpoint inhibitors, such as anti-PD-1, have shown modest improvements in survival for RCC, it is difficult to identify responders from non-responders. Attempts to elucidate the mechanisms associated with differential response to checkpoint inhibitors have been limited by small sample size making it difficult to detect meaningful associations. We utilized existing large datasets from The Cancer Genome Atlas (TCGA) to first find predictors of disease aggressiveness in the tumor microenvironment (TME) and hypothesized that these same predictors may influence response to immunotherapy. We found primary metastatic (M1-stage IV) tumors exhibit high immune infiltration, and high TP53-inactivation induced senescence activity compared to non-metastatic (M0-Stage I/II) tumors. Moreover, some TME features inferred from deconvolution algorithms, which differ between M0 and M1 tumors, also influence overall survival. A focused analysis identified interactions between tumor TP53-inactivation induced senescence activity and expression of inflammatory molecules in pre-treatment RCC tumors, which predict both change in tumor size and response to checkpoint blockade therapy. We also noted frequency of inactivating mutations in the protein polybromo-1 (PBRM1) gene was found to be negatively associated with TP53-inactivation induced senescence enrichment. Our findings suggest a mechanism by which tumor TP53-inactivation induced senescence can modulate the TME and thereby influence outcome from checkpoint blockade therapy.
Keywords
- cellular senescence
- deconvolution
- metastasis
- molecular modeling
- renal clear cell carcinoma
- tumor immunobiology
Thyroid hormones have been recently linked to senescence and longevity. Given the recent description of TSHB mRNA in human adipose tissue (AT), we aimed to investigate the relationship between local AT TSH and adipose tissue senescence. TSHB mRNA (measured by real-time PCR) and markers of adipose tissue senescence [BAX, DBC1, TP53, TNF (real-time PCR), telomere length (Telo TAGGG Telomere Length Assay) and lipidomics (liquid chromatography mass spectrometry)] were analysed in subcutaneous (SAT) and visceral (VAT) AT from euthyroid subjects. The chronic effects of TSH were also investigated in AT from hypothyroid rats and after recombinant human TSH (rhTSH) administration in human adipocytes. Both VAT and SAT TSHB gene expression negatively correlated with markers of AT cellular senescence (BAX, DBC1, TP53, TNF gene expression and specific glucosylceramides) and positively associated with telomere length. Supporting these observations, both rhTSH administration in human adipocytes and increased TSH in hypothyroid rats resulted in decreased markers of cellular senescence (Bax and Tp53 mRNA) in both gonadal and subcutaneous white adipose tissue. These data point to a possible role of TSH in AT cellular senescence.
MeSH Terms
- Adult
- Animals
- Biomarkers
- Blood Glucose
- Cellular Senescence
- Female
- Gene Expression Regulation
- Humans
- Hypothyroidism
- Intra-Abdominal Fat
- Male
- Middle Aged
- Rats
- Rats, Sprague-Dawley
- Subcutaneous Fat
- Telomere Homeostasis
- Thyrotropin
- Thyrotropin, beta Subunit
- Tumor Suppressor Protein p53
- bcl-2-Associated X Protein
Keywords
- Adipose tissue
- Cellular senescence
- Euthyroidism
- Hypothyroidism
- Thyroid-stimulating hormone
Previous studies on the role of TP53 mutation in breast cancer treatment response and survival are contradictory and inconclusive, limited by the use of different endpoints to determine clinical significance and by small sample sizes that prohibit stratification by treatment. We utilized large datasets to examine overall survival according to TP53 mutation status in patients across multiple clinical features and treatments. Confirming other studies, we found that in all patients and in hormone therapy-treated patients, TP53 wild-type status conferred superior 5-year overall survival, but survival curves crossed at 10 or more years. In contrast, further stratification within the large dataset revealed that in patients receiving chemotherapy and no hormone therapy, wild-type TP53 status conferred remarkably poor overall survival. This previously unrecognized inferior survival is consistent with p53 inducing arrest/senescence instead of apoptosis. Addition of hormone therapy to chemotherapy improved survival notably in patients with TP53 wild-type tumors, but not mutant, suggesting hormone therapy could eradicate arrested/senescent cells. Testing this, we found that estrogen receptor-positive, TP53 wild-type breast cancer cells that were made senescent by doxorubicin treatment were sensitive to tamoxifen. The poor survival of chemotherapy-treated patients with TP53 wild-type tumors may be improved by strategies to eliminate senescent cells, including the addition of hormone therapy when appropriate.
MeSH Terms
- Antineoplastic Combined Chemotherapy Protocols
- Breast Neoplasms
- Doxorubicin
- Female
- Humans
- Kaplan-Meier Estimate
- MCF-7 Cells
- Mutation
- Prognosis
- Receptor, ErbB-2
- Receptors, Estrogen
- Receptors, Progesterone
- Tamoxifen
- Tumor Suppressor Protein p53
Keywords
- Breast cancer
- Chemotherapy
- Hormone therapy
- Senescence
- Survival
- TP53
Macroautophagy/autophagy is considered as an evolutionarily conserved cellular catabolic process. In this study, we aimed to elucidate the role of autophagy in vascular smooth muscle cells (SMCs) on atherosclerosis. SMCs cultured from mice with SMC-specific deletion of the essential autophagy gene atg7 (Atg7cKO) showed reduced serum-induced cell growth, increased cell death, and decreased cell proliferation rate. Furthermore, 7-ketocholestrerol enhanced apoptosis and the expression of CCL2 (chemokine [C-C motif] ligand 2) with the activation of TRP53, the mouse ortholog of human and rat TP53, in SMCs from Atg7cKO mice. In addition, Atg7cKO mice crossed with Apoe (apolipoprotein E)-deficient mice (apoeKO; Atg7cKO:apoeKO) showed reduced medial cellularity and increased TUNEL-positive cells in the descending aorta at 10 weeks of age. Intriguingly, Atg7cKO: apoeKO mice fed a Western diet containing 1.25% cholesterol for 14 weeks showed a reduced survival rate. Autopsy of the mice demonstrated the presence of aortic rupture. Analysis of the descending aorta in Atg7cKO:apoeKO mice showed increased plaque area, increased TUNEL-positive area, decreased SMC-positive area, accumulation of macrophages in the media, and adventitia and perivascular tissue, increased CCL2 expression in SMCs in the vascular wall, medial disruption, and aneurysm formation. In conclusion, our data suggest that defective autophagy in SMCs enhances atherosclerotic changes with outward arterial remodeling.
MeSH Terms
- Animals
- Aorta
- Apolipoproteins E
- Atherosclerosis
- Autophagy
- Autophagy-Related Protein 7
- Cell Death
- Cells, Cultured
- Disease Models, Animal
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Muscle, Smooth, Vascular
- Plaque, Atherosclerotic
- Vascular Remodeling
Keywords
- Aneurysm
- atherosclerosis
- autophagy
- cell death
- senescence
- smooth muscle cells
The activation of TP53 is well known to exert tumor suppressive effects. We have detected a [i]primate-specific[/i] adrenal androgen-mediated tumor suppression system in which circulating DHEAS is converted to DHEA specifically in cells in which TP53 has been [i]inactivated[/i] DHEA is an [i]uncompetitive[/i] inhibitor of glucose-6-phosphate dehydrogenase (G6PD), an enzyme indispensable for maintaining reactive oxygen species within limits survivable by the cell. Uncompetitive inhibition is otherwise unknown in natural systems because it becomes [i]irreversible[/i] in the presence of high concentrations of substrate and inhibitor. In addition to primate-specific circulating DHEAS, a unique, primate-specific sequence motif that disables an activating regulatory site in the glucose-6-phosphatase (G6PC) promoter was also required to enable function of this previously unrecognized tumor suppression system. In human somatic cells, loss of TP53 thus triggers activation of DHEAS transport proteins and steroid sulfatase, which converts circulating DHEAS into intracellular DHEA, and hexokinase which increases glucose-6-phosphate substrate concentration. The triggering of these enzymes in the TP53-affected cell combines with the primate-specific G6PC promoter sequence motif that enables G6P substrate accumulation, driving uncompetitive inhibition of G6PD to irreversibility and ROS-mediated cell death. By this catastrophic 'kill switch' mechanism, TP53 mutations are effectively prevented from initiating tumorigenesis in the somatic cells of humans, the primate with the highest peak levels of circulating DHEAS. TP53 mutations in human tumors therefore represent fossils of kill switch failure resulting from an age-related decline in circulating DHEAS, a potentially reversible artifact of hominid evolution.
MeSH Terms
- Humans
- Neoplasms
- Tumor Suppressor Protein p53
Keywords
- DHEAS
- PTEN
- TP53
- aging and cancer
- animal models of cancer
- endocrine system
- endocrine-related cancer
- glucose-6-phosphate dehydrogenase
- p53
- p53-knockout mouse
- tumor suppression
Dysregulation of plasma lipids is associated with age-related cardiovascular diseases. L5, the most electronegative subfraction of chromatographically resolved low-density lipoprotein (LDL), induces endothelial dysfunction, whereas the least electronegative subfraction, L1, does not. In this study, we examined the effects of L5 on endothelial senescence and its underlying mechanisms. C57B6/J mice were intravenously injected with L5 or L1 (2 mg kg day ) from human plasma. After 4 weeks, nuclear γH2AX deposition and senescence-associated β-galactosidase staining indicative of DNA damage and premature senescence, respectively, were increased in the aortic endothelium of L5-treated but not L1-treated mice. Similar to that, in Syrian hamsters with elevated serum L5 levels induced by a high-fat diet, nuclear γH2AX deposition and senescence-associated β-galactosidase staining were increased in the aortic endothelium. This phenomenon was blocked in the presence of N-acetyl-cysteine (free-radical scavenger) or caffeine (ATM blocker), as well as in lectin-like oxidized LDL receptor-1 (LOX-1) knockout mice. In cultured human aortic endothelial cells, L5 augmented mitochondrial oxygen consumption and mitochondrial free-radical production, which led to ATM activation, nuclear γH2AX deposition, Chk2 phosphorylation, and TP53 stabilization. L5 also decreased human telomerase reverse transcriptase (hTERT) protein levels and activity. Pharmacologic or genetic manipulation of the reactive oxygen species (ROS)/ATM/Chk2/TP53 pathway efficiently blocked L5-induced endothelial senescence. In conclusion, L5 may promote mitochondrial free-radical production and activate the DNA damage response to induce premature vascular endothelial senescence that leads to atherosclerosis. Novel therapeutic strategies that target L5-induced endothelial senescence may be used to prevent and treat atherosclerotic vascular disease.
MeSH Terms
- Animals
- Cells, Cultured
- Cellular Senescence
- Endothelium, Vascular
- Humans
- Injections, Intravenous
- Lipoproteins, LDL
- Mesocricetus
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mitochondria
Keywords
- DNA damage response
- atherosclerosis
- electronegative lipoproteins
- mitochondria
- premature senescence
- telomerase
We recently reported that in addition to its classical cytoplasmic location, the fast skeletal muscle Troponin T3 (TnT3) shuttles to the nucleus, where it appears to perform nonclassical transcription regulatory functions. Importantly, changes in the composition of the nucleus-localized pool of TnT3 and its fragments contribute to age-dependent muscle damage and wasting. Here, using ChIP-Seq, we demonstrate that TnT3 associates with DNA consensus sequences including the TGCCT motif, which is required for p53 binding to the promoter area of p53-related genes. Gene set enrichment analysis further demonstrated that the p53 pathway was the most significantly enriched pathway among genes annotated to the TnT3 ChIP-Seq peaks. We further demonstrated a strong correlation (r = 0.78, P = 1 × 10 ) between the expression levels of TNNT3 and TP53-inducible ribonucleotide reductase regulatory subunit M2B (RRM2B) in skeletal muscle tissue of 21 lean non-diabetic human subjects and a significant (P < 0.05) reduction in the levels of both gene transcripts in the third age-tertile group [42.3-70 years of age (yoa)] as compared to the second age-tertile (31.3-42.3 yoa). Of note, both TNNT3 and RRM2B expression levels negatively associated with total body fat mass (each with r = 0.49, P < 0.05), whereas RRM2B positively correlated with pancreatic β cell function (r = 0.47, P = 0.047). This work suggests that reduced TNNT3 gene expression is another mechanism leading to reduced TnT3 and excitation-contraction coupling with aging. Consequently, TnT3 appears to contribute to age-related sarcopenia and possibly other age-related deficiencies such as muscle insulin resistance and β cell dysfunction by interacting with TnT3-binding sequences in the promoter area of p53-related genes, among others, and consequently modulating the transcriptional regulation of these target genes.
MeSH Terms
- Adult
- Aged
- Cell Cycle Proteins
- Cell Line
- Cell Nucleus
- Consensus Sequence
- DNA
- Female
- Gene Expression Regulation
- Humans
- Male
- Middle Aged
- Muscle Cells
- Protein Binding
- Ribonucleotide Reductases
- Transcription, Genetic
- Troponin T
Keywords
- Aging
- Calcium channel
- Gene transcription
- Skeletal muscle
- Troponin T3
In human longevity studies, single nucleotide polymorphism (SNP) analysis identified a large number of genetic variants with small effects, yet not easily replicable in different populations. New insights may come from the combined analysis of different SNPs, especially when grouped by metabolic pathway. We applied this approach to study the joint effect on longevity of SNPs belonging to three candidate pathways, the insulin/insulin-like growth factor signalling (IIS), DNA repair and pro/antioxidant. We analysed data from 1,058 tagging SNPs in 140 genes, collected in 1825 subjects (1,089 unrelated nonagenarians from the Danish 1905 Birth Cohort Study and 736 Danish controls aged 46-55 years) for evaluating synergic interactions by SNPsyn. Synergies were further tested by the multidimensional reduction (MDR) approach, both intra- and interpathways. The best combinations (FDR<0.0001) resulted those encompassing IGF1R-rs12437963 and PTPN1-rs6067484, TP53-rs2078486 and ERCC2-rs50871, TXNRD1-rs17202060 and TP53-rs2078486, the latter two supporting a central role of TP53 in mediating the concerted activation of the DNA repair and pro-antioxidant pathways in human longevity. Results were consistently replicated with both approaches, as well as a significant effect on longevity was found for the GHSR gene, which also interacts with partners belonging to both IIS and DNA repair pathways (PAPPA, PTPN1, PARK7, MRE11A). The combination GHSR-MREA11, positively associated with longevity by MDR, was further found influencing longitudinal survival in nonagenarian females (p = .026). Results here presented highlight the validity of SNP-SNP interactions analyses for investigating the genetics of human longevity, confirming previously identified markers but also pointing to novel genes as central nodes of additional networks involved in human longevity.
MeSH Terms
- Aging
- Female
- Humans
- Longevity
- Male
- Polymorphism, Single Nucleotide
- Survival Analysis
Keywords
SNP
- aging
- epistasis
- genetic component of human longevity
- pathway-based analysis
- synergic interaction
Aging is a major risk factor for age-related diseases such as certain cancers. In this study, we developed Age Associated Gene Co-expression Identifier (AAGCI), a liquid association based method to infer age-associated gene co-expressions at thousands of biological processes and pathways across 9 human tissues. Several hundred to thousands of gene pairs were inferred to be age co-expressed across different tissues, the genes involved in which are significantly enriched in functions like immunity, ATP binding, DNA damage, and many cancer pathways. The age co-expressed genes are significantly overlapped with aging genes curated in the GenAge database across all 9 tissues, suggesting a tissue-wide correlation between age-associated genes and co-expressions. Interestingly, age-associated gene co-expressions are significantly different from gene co-expressions identified through correlation analysis, indicating that aging might only contribute to a small portion of gene co-expressions. Moreover, the key driver analysis identified biologically meaningful genes in important function modules. For example, [i]IGF1, ERBB2, TP53 and STAT5A[/i] were inferred to be key genes driving age co-expressed genes in the network module associated with function "T cell proliferation". Finally, we prioritized a few anti-aging drugs such as metformin based on an enrichment analysis between age co-expressed genes and drug signatures from a recent study. The predicted drugs were partially validated by literature mining and can be readily used to generate hypothesis for further experimental validations.
Keywords
- GTEx
- aging
- anti-aging drug prediction
- gene co-expression
- liquid association
Senescence is a terminal differentiation program that halts the growth of damaged cells and must be circumvented for cancer to arise. Here we describe a panel of genetic screens to identify genes required for replicative senescence. We uncover a role in senescence for the potent tumor suppressor and ATM substrate USP28. USP28 controls activation of both the TP53 branch and the GATA4/NFkB branch that controls the senescence-associated secretory phenotype (SASP). These results suggest a role for ubiquitination in senescence and imply a common node downstream from ATM that links the TP53 and GATA4 branches of the senescence response.
MeSH Terms
- Ataxia Telangiectasia Mutated Proteins
- Cellular Senescence
- GATA4 Transcription Factor
- Gene Expression Regulation
- Gene Library
- HCT116 Cells
- Humans
- Reproducibility of Results
- Tumor Suppressor Protein p53
- Ubiquitin Thiolesterase
- Ubiquitination
Keywords
- GATA4
- USP28
- senescence
Mantle cell lymphoma (MCL) is a B-cell hemopathy characterized by the t(11;14) translocation and the aberrant overexpression of cyclin D1. This results in an unrestrained cell proliferation. Other genetic alterations are common in MCL cells such as SOX11 expression, mutations of ATM and/or TP53 genes, activation of the NF-κB signaling pathway and NOTCH receptors. These alterations lead to the deregulation of the apoptotic machinery and resistance to drugs. We observed that among a panel of MCL cell lines, REC1 cells were resistant towards genotoxic stress. We studied the molecular basis of this resistance. We analyzed the cell response regarding apoptosis, senescence, cell cycle arrest, DNA damage response and finally the 26S proteasome activity following a genotoxic treatment that causes double strand DNA breaks. MCL cell lines displayed various sensitivity/resistance towards genotoxic stress and, in particular, REC1 cells did not enter apoptosis or senescence after an etoposide treatment. Moreover, the G2/M cell cycle checkpoint was deficient in REC1 cells. We observed that three main actors of apoptosis, senescence and cell cycle regulation (cyclin D1, MCL1 and CDC25A) failed to be degraded by the proteasome machinery in REC1 cells. We ruled out a default of the βTrCP E3-ubiquitine ligase but detected a lowered 26S proteasome activity in REC1 cells compared to other cell lines. The resistance of MCL cells to genotoxic stress correlates with a low 26S proteasome activity. This could represent a relevant biomarker for a subtype of MCL patients with a poor response to therapies and a high risk of relapse.
MeSH Terms
- Antineoplastic Agents, Phytogenic
- Apoptosis
- Cell Line, Tumor
- DNA Breaks, Double-Stranded
- DNA Repair
- DNA, Neoplasm
- Drug Resistance, Neoplasm
- Etoposide
- Gene Expression Regulation, Neoplastic
- Humans
- Lymphoma, Mantle-Cell
- Proteasome Endopeptidase Complex
Keywords
- 26S proteasome
- Apoptosis
- B-cell lymphoma
- Cell cycle
- DNA repair
- Double-strand break
- PSMB6
- Resistance/sensitivity
- Senescence
- Ubiquitin ligase
A deeper understanding of the conserved molecular mechanisms in different taxa have been made possible only because of the evolutionary conservation of crucial signaling pathways. In the present study, we explored the molecular evolutionary pattern of selection signatures in 51 species for 10 genes which are important components of NAD /Sirtuin pathway and have already been directly linked to lifespan extension in worms and mice. Selection pressure analysis using PAML program revealed that MRPS5 and PPARGC1A were under significant constraints because of their functional significance. FOXO3a also displayed strong purifying selection. All three sirtuins, which were SIRT1, SIRT2 and SIRT6, displayed a great degree of conservation between taxa, which is consistent with the previous report. A significant evolutionary constraint is seen on the anti-oxidant gene, SOD3. As expected, TP53 gene was under significant selection pressure in mammals, owing to its major role in tumor progression. Poly-ADP-ribose polymerase (PARP) genes displayed the most sites under positive selection. Further 3D structural analysis of PARP1 and PARP2 protein revealed that some of these positively selected sites caused a change in the electrostatic potential of the protein structure, which may allow a change in its interaction with other proteins and molecules ultimately leading to difference in the function. Although the functional significance of the positively selected sites could not be established in the variants databases, yet it will be interesting to see if these sites actually affect the function of PARP1 and PARP2.
MeSH Terms
- Aging
- Animals
- Evolution, Molecular
- Helminths
- Humans
- Mice
- NAD
- Poly (ADP-Ribose) Polymerase-1
- Poly(ADP-ribose) Polymerases
- Selection, Genetic
- Signal Transduction
- Sirtuins
The National Comprehensive Cancer Network recommends that women who carry gene variants that confer substantial risk for breast cancer consider risk-reduction strategies, that is, enhanced surveillance (breast magnetic resonance imaging and mammography) or prophylactic surgery. Pathogenic variants can be detected in women with a family history of breast or ovarian cancer syndromes by multigene panel testing. To investigate whether using a seven-gene test to identify women who should consider risk-reduction strategies could cost-effectively increase life expectancy. We estimated effectiveness and lifetime costs from a payer perspective for two strategies in two hypothetical cohorts of women (40-year-old and 50-year-old cohorts) who meet the National Comprehensive Cancer Network-defined family history criteria for multigene testing. The two strategies were the usual test strategy for variants in BRCA1 and BRCA2 and the seven-gene test strategy for variants in BRCA1, BRCA2, TP53, PTEN, CDH1, STK11, and PALB2. Women found to have a pathogenic variant were assumed to undergo either prophylactic surgery or enhanced surveillance. The incremental cost-effectiveness ratio for the seven-gene test strategy compared with the BRCA1/2 test strategy was $42,067 per life-year gained or $69,920 per quality-adjusted life-year gained for the 50-year-old cohort and $23,734 per life-year gained or $48,328 per quality-adjusted life-year gained for the 40-year-old cohort. In probabilistic sensitivity analysis, the seven-gene test strategy cost less than $100,000 per life-year gained in 95.7% of the trials for the 50-year-old cohort. Testing seven breast cancer-associated genes, followed by risk-reduction management, could cost-effectively improve life expectancy for women at risk of hereditary breast cancer.
MeSH Terms
- Adult
- Age Factors
- Aged
- Aged, 80 and over
- Biomarkers, Tumor
- Breast Neoplasms
- Cost-Benefit Analysis
- Decision Support Techniques
- Early Detection of Cancer
- Female
- Gene Expression Profiling
- Genetic Predisposition to Disease
- Genetic Testing
- Health Care Costs
- Heredity
- Humans
- Life Expectancy
- Magnetic Resonance Imaging
- Mammography
- Mastectomy
- Middle Aged
- Models, Economic
- Patient Selection
- Phenotype
- Predictive Value of Tests
- Prognosis
- Quality-Adjusted Life Years
- Risk Assessment
- Risk Factors
- Watchful Waiting
Keywords
- BRCA
- breast cancer
- cost-effectiveness
- multigene panel testing
Telomerase reverse transcriptase (TERT) is the protein component of telomerase complex. Evidence has accumulated showing that the nontelomeric functions of TERT are independent of telomere elongation. However, the mechanisms governing the interaction between TERT and its target genes are not clearly revealed. The biological functions of TERT are not fully elucidated and have thus far been underestimated. To further explore these functions, we investigated TERT interaction networks using multiple bioinformatic databases, including BioGRID, STRING, DAVID, GeneCards, GeneMANIA, PANTHER, miRWalk, mirTarBase, miRNet, miRDB, and TargetScan. In addition, network diagrams were built using Cytoscape software. As competing endogenous RNAs (ceRNAs) are endogenous transcripts that compete for the binding of microRNAs (miRNAs) by using shared miRNA recognition elements, they are involved in creating widespread regulatory networks. Therefore, the ceRNA regulatory networks of TERT were also investigated in this study. Interestingly, we found that the three genes PABPC1, SLC7A11, and TP53 were present in both TERT interaction networks and ceRNAs target genes. It was predicted that TERT might play nontelomeric roles in the generation or development of some rare diseases, such as Rift Valley fever and dyscalculia. Thus, our data will help to decipher the interaction networks of TERT and reveal the unknown functions of telomerase in cancer and aging-related diseases.
MeSH Terms
- Computational Biology
- Data Mining
- Databases as Topic
- Gene Ontology
- Gene Regulatory Networks
- Humans
- Molecular Sequence Annotation
- RNA
- Software
- Telomerase
- Telomere
Keywords
- aging
- bioinformatics
- cancer
- telomerase
- telomere
Pilocytic astrocytoma (PA) is the most frequent pediatric brain tumor. Activation of the MAPK pathway is well established as the oncogenic driver of the disease. It is most frequently caused by KIAA1549:BRAF fusions, and leads to oncogene induced senescence (OIS). OIS is thought to be a major reason for growth arrest of PA cells in vitro and in vivo, preventing establishment of PA cultures. Hence, valid preclinical models are currently very limited, but preclinical testing of new compounds is urgently needed. We transduced the PA short-term culture DKFZ-BT66 derived from the PA of a 2-year old patient with a doxycycline-inducible system coding for Simian Vacuolating Virus 40 Large T Antigen (SV40-TAg). SV40-TAg inhibits TP53/CDKN1A and [[CDKN2A]]/RB1, two pathways critical for OIS induction and maintenance. DNA methylation array and KIAA1549:BRAF fusion analysis confirmed pilocytic astrocytoma identity of DKFZ-BT66 cells after establishment. Readouts were analyzed in proliferating as well as senescent states, including cell counts, viability, cell cycle analysis, expression of SV40-Tag, [[CDKN2A]] (p16), CDKN1A (p21), and TP53 (p53) protein, and gene-expression profiling. Selected MAPK inhibitors (MAPKi) including clinically available MEK inhibitors (MEKi) were tested in vitro. Expression of SV40-TAg enabled the cells to bypass OIS and to resume proliferation with a mean doubling time of 45h allowing for propagation and long-term culture. Withdrawal of doxycycline led to an immediate decrease of SV40-TAg expression, appearance of senescent morphology, upregulation of CDKI proteins and a subsequent G1 growth arrest in line with the re-induction of senescence. DKFZ-BT66 cells still underwent replicative senescence that was overcome by TERT expression. Testing of a set of MAPKi revealed differential responses in DKFZ-BT66. MEKi efficiently inhibited MAPK signaling at clinically achievable concentrations, while BRAF V600E- and RAF Type II inhibitors showed paradoxical activation. Taken together, we have established the first patient-derived long term expandable PA cell line expressing the KIAA1549:BRAF-fusion suitable for preclinical drug testing.
MeSH Terms
- Antigens, Polyomavirus Transforming
- Astrocytoma
- Blotting, Western
- Brain Neoplasms
- Cell Culture Techniques
- Cell Line, Tumor
- Cell Proliferation
- Cellular Senescence
- Child, Preschool
- Drug Screening Assays, Antitumor
- Gene Expression Profiling
- Humans
- Male
- Oncogene Proteins, Fusion
- Polymerase Chain Reaction
- Proto-Oncogene Proteins B-raf
- Transcriptome
- Transduction, Genetic
Keywords
- KIAA1549:BRAF-fusion
- MAPK-inhibitors
- oncogene-induced senescence (OIS)
- pediatric low grade glioma
- pilocytic astrocytoma
TP53 is a critical tumor suppressor gene that regulates cell cycle progression, apoptosis, cellular senescence and many other properties critical for control of normal cellular growth and death. Due to the pleiotropic effects that TP53 has on gene expression and cellular physiology, mutations at this tumor suppressor gene result in diverse physiological effects. T53 mutations are frequently detected in numerous cancers. The expression of TP53 can be induced by various agents used to treat cancer patients such as chemotherapeutic drugs and ionizing radiation. Radiation will induce Ataxia telangiectasia mutated (ATM) and other kinases that results in the phosphorylation and activation of TP53. TP53 is also negatively regulated by other mechanisms, such as ubiquitination by ligases such as MDM2. While TP53 has been documented to control the expression of many "classical" genes (e.g., p21 , PUMA, Bax) by transcriptional mechanisms for quite some time, more recently TP53 has been shown to regulate microRNA (miR) gene expression. Different miRs can promote oncogenesis (oncomiR) whereas others act to inhibit tumor progression (tumor suppressor miRs). Targeted therapies to stabilize TP53 have been developed by various approaches, MDM2/MDM4 inhibitors have been developed to stabilize TP53 in TP53-wild type (WT) tumors. In addition, small molecules have been isolated that will reactivate certain mutant TP53s. Both of these types of inhibitors are in clinical trials. Understanding the actions of TP53 may yield novel approaches to suppress cancer, aging and other health problems.
MeSH Terms
- Antineoplastic Agents
- Apoptosis Regulatory Proteins
- Aza Compounds
- Bridged Bicyclo Compounds, Heterocyclic
- Cell Cycle
- Cell Proliferation
- Cellular Senescence
- Cyclin-Dependent Kinase Inhibitor p21
- Gene Expression Regulation, Neoplastic
- Humans
- MicroRNAs
- Neoplasm Invasiveness
- Neoplasm Metastasis
- Neoplasms
- Proto-Oncogene Proteins
- Signal Transduction
- Tumor Suppressor Protein p53
- bcl-2-Associated X Protein
Keywords
- Cellular senescence
- Invasion
- MDM2
- Metastasis
- Nutlin-3 chemosensitivity
- TP53
- miRs
Microphthalmia-associated transcription factor (MITF) plays a crucial role in the melanogenesis and proliferation of melanocytes that is dependent on its abundance and modification. Here, we report that epidermal growth factor (EGF) induces senescence and cyclin-dependent kinase inhibitor 1A (CDKN1A) expression that is related to MITF. We found that MITF could bind TP53 to regulate CDKN1A. Furthermore, the interaction between MITF and TP53 is dependent on AKT activity. We found that AKT phosphorylates MITF at S510. Phosphorylated MITF S510 enhances its affinity to TP53 and promotes CDKN1A expression. Meanwhile, the unphosphorylative MITF promotes TYR expression. The levels of p-MITF-S510 are low in 90% human melanoma samples. Thus the level of p-MITF-S510 could be a possible diagnostic marker for melanoma. Our findings reveal a mechanism for regulating MITF functions in response to EGF stimulation and suggest a possible implementation for preventing the over proliferation of melanoma cells.
MeSH Terms
- Cell Line, Tumor
- Cell Proliferation
- Cellular Senescence
- Cyclin-Dependent Kinase Inhibitor p21
- Gene Expression Regulation, Neoplastic
- Humans
- Inhibitor of Differentiation Proteins
- Melanoma
- Microphthalmia-Associated Transcription Factor
- Phosphorylation
- Proteolysis
- Proto-Oncogene Proteins c-akt
- Tumor Suppressor Protein p53
Keywords
- AKT
- MITF
- Phosphorylation
- Senescence
- TP53
Head and neck squamous cell carcinoma (HNSCC) is a cancer with well-defined tumor causes such as HPV infection, smoking and drinking. Using The Cancer Genome Atlas (TCGA) HNSCC cohort we systematically studied the mutational load as well as patterns related to patient age in HNSCC. To obtain a homogenous set we excluded all patients with HPV infection as well as wild type TP53. We found that the overall mutational load is higher in patients of old age. Through unsupervised hierarchical clustering, we detected distinct mutational clusters in very young as well as very old patients. In the group of old patients, we identified four enriched pathways ("Axon Guidance", "ECM-Receptor Interaction", "Focal Adhesion" and "Notch Signaling") that are only sporadically mutated in the other age groups. Our findings indicate that the four pathways regulate cell motility, tumor invasion and angiogenesis supposedly leading to less aggressive tumors in older age patients. Importantly, we did not see a strict pattern of genes always mutated in older age but rather an accumulation of mutations in the same pathways. Our study provides indications of age-dependent differences in mutational backgrounds of tumors that might be relevant for treatment approaches of HNSCCs patients.
MeSH Terms
- Adult
- Age Factors
- Aged
- Aged, 80 and over
- Aging
- Carcinoma, Squamous Cell
- Cohort Studies
- Gene Frequency
- Genetic Predisposition to Disease
- Head and Neck Neoplasms
- Humans
- Middle Aged
- Mutation
- Signal Transduction
- Young Adult
Keywords
- Gerotarget
- aging
- genomics
- head and neck squamous cell carcinoma
- sequencing
- somatic mutations
Geriatric glioblastoma (GBM) patients have a poorer prognosis than younger patients, but IDH1/2 mutations (more common in younger patients) confer a favorable prognosis. We compared key GBM molecular alterations between an elderly (age ≥ 70) and younger (18 < = age < = 45) cohort to explore potential therapeutic opportunities. Alterations more prevalent in the young GBM cohort compared to the older cohort (P < 0.05) were: overexpression of ALK, RRM1, TUBB3 and mutation of ATRX, BRAF, IDH1, and TP53. However, PTEN mutation was significantly more frequent in older patients. Among patients with wild-type IDH1/2 status, TOPO1 expression was higher in younger patients, whereas MGMT methylation was more frequent in older patients. Within the molecularly-defined IDH wild-type GBM cohort, younger patients had significantly more mutations in PDGFRA, PTPN11, SMARCA4, BRAF and TP53. GBMs from 178 elderly patients and 197 young patients were analyzed using DNA sequencing, immunohistochemistry, in situ hybridization, and MGMT-methylation assay to ascertain mutational and amplification/expressional status. Significant molecular differences occurred in GBMs from elderly and young patients. Except for the older cohort's more frequent PTEN mutation and MGMT methylation, younger patients had a higher frequency of potential therapeutic targets.
MeSH Terms
- Adult
- Age Factors
- Aged
- Aging
- Biomarkers, Tumor
- Brain Neoplasms
- Cohort Studies
- DNA Methylation
- DNA Mutational Analysis
- ErbB Receptors
- Gene Expression Regulation, Neoplastic
- Glioblastoma
- Humans
- Mutation
- Tumor Suppressor Protein p53
Keywords
- DNA sequencing
- GBM
- mutational analysis
MicroRNAs (miRNAs) negatively regulate the expression of the target genes by binding to 'seed sequences' in the 3'‑untranslated region (3'‑UTR) mRNA transcripts, and the variants within or nearby 'seed sequences' may compromise or enhance miRNA/mRNA interaction leading to either 'loss‑of‑function' or 'gain‑of‑function' effects. Cataracts are the leading cause of blindness worldwide and are characterized by progressive aggregation and precipitation of lens proteins, and the development of age‑related cataracts is associated with dysregulated cellular activities of lens epithelial cells. Luciferase assays and online miRNA databases were used to validate that tumor protein p53 (TP53) is the target gene of miR‑125b. Furthermore, reverse transcription‑quantitative polymerase chain reaction and western blotting were conducted to detect expression levels of miR‑125b and TP53 in different groups of cells transfected with miR‑125b mimics or inhibitors. In addition, flow cytometry analysis and the MTT assay were conducted to detect the effects of miR‑125b on apoptosis and cell viability. The current study demonstrated that the rs78378222 polymorphism minor allele introduces a novel potential miR‑125b binding site in the TP53 3'‑UTR with a consecutive 8‑bp perfect match, creating a 'gain‑of‑function' variant and affecting the regulation of TP53 expression. A luciferase assay demonstrated that transfection of lens epithelial cells with wild type TP53 3'‑UTR significantly reduced the luciferase activity of the miR‑125b overexpressing cells compared with scramble controls. In addition, the luciferase activity of miR‑125b overexpressing cells transfected with the construct containing the rs78378222 polymorphism minor allele was also reduced compared with cells transfected with the wild type 3'‑UTR. Furthermore, it was demonstrated that the expression level of miR‑125 was comparable in epithelial cells from patients with age‑associated cataracts and controls, whereas the expression level of TP53 was significantly higher in the cataract group compared with controls. Additionally, transfection with 50 nM miR‑125b mimics markedly reduced the mRNA and protein expression levels of TP53 in the cultured lens epithelial cells, and miR‑125b significantly induced apoptosis in the epithelial cells compared with negative control cells. In conclusion, TP53 was identified as a target of miR‑125b, and the minor allele of the rs78378222 polymorphism promoted the miR-125b/TP53 mRNA interaction.
MeSH Terms
- 3' Untranslated Regions
- Aging
- Alleles
- Apoptosis
- Base Sequence
- Binding Sites
- Cataract
- Epithelial Cells
- Gene Expression
- Genetic Association Studies
- Genetic Predisposition to Disease
- Humans
- MicroRNAs
- Polymorphism, Single Nucleotide
- RNA Interference
- Tumor Suppressor Protein p53
The mechanisms leading to brain tumor formation are poorly understood. Using Ptch1 mice as a medulloblastoma model, sequential mutations were found to shape tumor evolution. Initially, medulloblastoma preneoplastic lesions display loss of heterozygosity of the Ptch1 wild-type allele, an event associated with cell senescence in preneoplasia. Subsequently, p53 mutations lead to senescence evasion and progression from preneoplasia to medulloblastoma. These findings are consistent with a model where high levels of Hedgehog signaling caused by the loss of the tumor suppressor Ptch1 lead to oncogene-induced senescence and drive p53 mutations. Thus, cell senescence is an important characteristic of a subset of SHH medulloblastoma and might explain the acquisition of somatic TP53 mutations in human medulloblastoma. This mode of medulloblastoma formation contrasts with the one characterizing Li-Fraumeni patients with medulloblastoma, where TP53 germ-line mutations cause chromothriptic genomic instability and lead to mutations in Hedgehog signaling genes, which drive medulloblastoma growth. Here we discuss in detail these 2 alternative mechanisms leading to medulloblastoma tumorigenesis.
MeSH Terms
- Animals
- Cellular Senescence
- Hedgehog Proteins
- Humans
- Medulloblastoma
- Mutation
- Signal Transduction
- Tumor Suppressor Protein p53
Keywords
- Medulloblastoma; p53
- Ptch1
- TP53
- cell senescence
- preneoplasia
- sonic hedgehog
The Long Life Family Study (LLFS) is an international study to identify the genetic components of various healthy aging phenotypes. We hypothesized that pedigree-specific rare variants at longevity-associated genes could have a similar functional impact on healthy phenotypes. We performed custom hybridization capture sequencing to identify the functional variants in 464 candidate genes for longevity or the major diseases of aging in 615 pedigrees (4,953 individuals) from the LLFS, using a multiplexed, custom hybridization capture. Variants were analyzed individually or as a group across an entire gene for association to aging phenotypes using family based tests. We found significant associations to three genes and nine single variants. Most notably, we found a novel variant significantly associated with exceptional survival in the 3' UTR OBFC1 in 13 individuals from six pedigrees. OBFC1 (chromosome 10) is involved in telomere maintenance, and falls within a linkage peak recently reported from an analysis of telomere length in LLFS families. Two different algorithms for single gene associations identified three genes with an enrichment of variation that was significantly associated with three phenotypes (GSK3B with the Healthy Aging Index, NOTCH1 with diastolic blood pressure and TP53 with serum HDL). Sequencing analysis of family-based associations for age-related phenotypes can identify rare or novel variants.
MeSH Terms
- Aged
- Female
- Genetic Association Studies
- Genetic Testing
- Genetic Variation
- High-Throughput Nucleotide Sequencing
- Humans
- Longevity
- Male
- Pedigree
- Phenotype
Keywords
- Aging
- Family
- Genetics
- Genomics
- Geriatrics
- Pedigrees
- Sequencing
Human respiratory syncytial virus (HRSV) accounts for the majority of lower respiratory tract infections during infancy and childhood and is associated with significant morbidity and mortality. HRSV provokes a proliferation arrest and characteristic syncytia in cellular systems such as immortalized epithelial cells. We show here that HRSV induces the expression of DNA damage markers and proliferation arrest such as P-TP53, P-ATM, CDKN1A and γH2AFX in cultured cells secondary to the production of mitochondrial reactive oxygen species (ROS). The DNA damage foci contained γH2AFX and [[TP53BP1]], indicative of double-strand breaks (DSBs) and could be reversed by antioxidant treatments such as N-Acetylcysteine (NAC) or reduced glutathione ethyl ester (GSHee). The damage observed is associated with the accumulation of senescent cells, displaying a canonical senescent phenotype in both mononuclear cells and syncytia. In addition, we show signs of DNA damage and aging such as γH2AFX and [[CDKN2A]] expression in the respiratory epithelia of infected mice long after viral clearance. Altogether, these results show that HRSV triggers a DNA damage-mediated cellular senescence program probably mediated by oxidative stress. The results also suggest that this program might contribute to the physiopathology of the infection, tissue remodeling and aging, and might be associated to long-term consequences of HRSV infections.
MeSH Terms
- A549 Cells
- Acetylcysteine
- Animals
- Cell Line
- Cellular Senescence
- Cyclin-Dependent Kinase Inhibitor p16
- Cyclin-Dependent Kinase Inhibitor p18
- DNA Breaks, Double-Stranded
- DNA Damage
- Glutathione
- Histones
- Host-Pathogen Interactions
- Humans
- Mice
- Oxidative Stress
- Reactive Oxygen Species
- Respiratory Mucosa
- Respiratory Syncytial Virus Infections
- Respiratory Syncytial Virus, Human
Keywords
- DNA damage
- ROS
- cellular senescence
- human respiratory
- syncytial virus
Tocotrienols have been known for their antioxidant properties besides their roles in cellular signalling, gene expression, immune response and apoptosis. This study aimed to determine the molecular mechanism of tocotrienol-rich fraction (TRF) in preventing cellular senescence of human diploid fibroblasts (HDFs) by targeting the genes in senescence-associated signalling pathways. Real time quantitative PCR (qRT-PCR) was utilized to evaluate the expression of genes involved in these pathways. Our findings showed that SOD1 and CCS-1 were significantly down-regulated in pre-senescent cells while CCS-1 and PRDX6 were up-regulated in senescent cells (p<0.05). Treatment with TRF significantly down-regulated SOD1 in pre-senescent and senescent HDFs, up-regulated SOD2 in senescent cells, CAT in young HDFs, GPX1 in young and pre-senescent HDFs, and CCS-1 in young, pre-senescent and senescent HDFs (p<0.05). TRF treatment also caused up-regulation of FOXO3A in all age groups of cells (p<0.05). The expression of TP53, PAK2 and [[CDKN2A]] was significantly increased in senescent HDFs and treatment with TRF significantly down-regulated TP53 in senescent cells (p<0.05). MAPK14 was significantly up-regulated (p<0.05) in senescent HDFs while no changes was observed on the expression of JUN. TRF treatment, however, down-regulated MAPK14 in young and senescent cells and up-regulated JUN in young and pre-senescent HDFs (p<0.05). TRF modulated the expression of genes involved in senescence-associated signalling pathways during replicative senescence of HDFs.
MeSH Terms
- Antioxidants
- Cell Differentiation
- Cell Proliferation
- Cells, Cultured
- Cellular Senescence
- DNA Damage
- Diploidy
- Down-Regulation
- Fibroblasts
- Genetic Markers
- Humans
- Insulins
- Real-Time Polymerase Chain Reaction
- Signal Transduction
- Tocotrienols
- Up-Regulation
Keywords
- Cellular senescence
- Genes expression
- Senescence-associated signalling pathways
- Tocotrienol-rich fraction
Conclusion EBV radiosensitized the p53 mutant tobacco associated head and neck cell line, FaDu. Objectives In the head and neck, HPV is a major risk factor associated with tonsil and base of tongue cancers, while a majority of undifferentiated nasopharyngeal cancers are positive for EBV. Clinically, head and neck tumors positive for HPV or EBV are more radiosensitive than tumors associated with tobacco and alcohol. This study aimed to evaluate whether viral infections can sensitize tobacco-associated head and neck squamous cell carcinoma cell line that harbors multiple mutations, especially TP53, to radiotherapy. Method Four FaDu cell lines (vector control - FaDu-DN; FaDu expressing HPV16 E6/E7 - FaDu-HPV; FaDu infected with EBV - FaDu-EBV; and FaDu-HPV infected with EBV - FaDu-HE) were evaluated for their radiation sensitivity using clonogenic assay. Cell cycle, protein expression, apoptosis, and cellular senescence were analyzed. Results FaDu-EBV and FaDu-HE exhibited significantly increased radiosensitivity in comparison with the control cell line. Radiation-induced cell cycle arrest was altered in all cell lines expressing viral genes. The observed distribution of cells at G1 and S phases was associated with a significant increase in expression of p21 protein along with decreased levels of pAKT/AKT and pERK/ERK ratio (p < 0.05) and increased cellular senescence (p < 0.05).
MeSH Terms
- Apoptosis
- Carcinoma, Squamous Cell
- Cell Cycle
- Cell Line, Tumor
- Epstein-Barr Virus Infections
- Genes, Viral
- Head and Neck Neoplasms
- Humans
- Male
- MicroRNAs
- Middle Aged
- Oncogenes
- Papillomavirus Infections
- RNA, Viral
- Tobacco Use
Keywords
- Squamous cell carcinoma
- cell cycle
- clonogenic assay
- co-infection
- radiation
- radiosensitivity
- senescence
Proton radiotherapy is becoming more common as protons induce more precise DNA damage at the tumor site with reduced side effects to adjacent normal tissues. However, the long-term biological effects of proton irradiation in cancer initiation compared with conventional photon irradiation are poorly characterized. In this study, using a human familial adenomatous polyposis syndrome susceptible mouse model, we show that whole-body irradiation with protons are more effective in inducing senescence-associated inflammatory responses (SIRs), which are involved in colon cancer initiation and progression. After proton irradiation, a subset of SIR genes (Troy, Sox17, Opg, Faim2, Lpo, Tlr2 and Ptges) and a gene known to be involved in invasiveness (Plat), along with the senescence-associated gene (P19Arf), are markedly increased. Following these changes, loss of Casein kinase Iα and induction of chronic DNA damage and TP53 mutations are increased compared with X-ray irradiation. Proton irradiation also increases the number of colonic polyps, carcinomas and invasive adenocarcinomas. Pretreatment with the non-steroidal anti-inflammatory drug, 2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oic acid-ethyl amide (CDDO-EA), reduces proton irradiation-associated SIR and tumorigenesis. Thus exposure to proton irradiation elicits significant changes in colorectal cancer initiation and progression that can be mitigated using CDDO-EA.
MeSH Terms
- Adenomatous Polyposis Coli
- Aging
- Animals
- Colorectal Neoplasms
- DNA Damage
- Disease Models, Animal
- Disease Progression
- Gene Expression Regulation, Neoplastic
- Humans
- Inflammation
- Mice, Inbred C57BL
- Mice, Knockout
- Mutation
- Oleanolic Acid
- Oxidative Stress
- Proton Therapy
- Reverse Transcriptase Polymerase Chain Reaction
- Survival Analysis
- Tumor Suppressor Protein p53
- Whole-Body Irradiation
Radiation-induced bystander effect, appearing as different biological changes in cells that are not directly exposed to ionizing radiation but are under the influence of molecular signals secreted by irradiated neighbors, have recently attracted considerable interest due to their possible implication for radiotherapy. However, various cells present diverse radiosensitivity and bystander responses that depend, inter alia, on genetic status including TP53, the gene controlling the cell cycle, DNA repair and apoptosis. Here we compared the ionizing radiation and bystander responses of human colorectal carcinoma HCT116 cells with wild type or knockout TP53 using a transwell co-culture system. The viability of exposed to X-rays (0-8 Gy) and bystander cells of both lines showed a roughly comparable decline with increasing dose. The frequency of micronuclei was also comparable at lower doses but at higher increased considerably, especially in bystander TP53-/- cells. Moreover, the TP53-/- cells showed a significantly elevated frequency of apoptosis, while TP53 / counterparts expressed high level of senescence. The cross-matched experiments where irradiated cells of one line were co-cultured with non-irradiated cells of opposite line show that both cell lines were also able to induce bystander effects in their counterparts, however different endpoints revealed with different strength. Potential mediators of bystander effects, IL-6 and IL-8, were also generated differently in both lines. The knockout cells secreted IL-6 at lower doses whereas wild type cells only at higher doses. Secretion of IL-8 by TP53-/- control cells was many times lower than that by TP53 / but increased significantly after irradiation. Transcription of the NFκBIA was induced in irradiated TP53 / mainly, but in bystanders a higher level was observed in TP53-/- cells, suggesting that TP53 is required for induction of NFκB pathway after irradiation but another mechanism of activation must operate in bystander cells.
MeSH Terms
- Adenocarcinoma
- Apoptosis
- Bystander Effect
- Cell Line, Tumor
- Cellular Senescence
- Colorectal Neoplasms
- Gene Expression Regulation, Neoplastic
- Genes, p53
- Humans
- I-kappa B Proteins
- Interleukin-6
- Interleukin-8
- Micronucleus Tests
- NF-KappaB Inhibitor alpha
- Neoplasm Proteins
- RNA, Messenger
- RNA, Neoplasm
- Tumor Suppressor Protein p53
Keywords
- Apoptosis
- Colon carcinoma cells differing in TP53 status
- NFκB pathway
- Premature senescence
- Pro-inflammatory cytokines IL-6 and IL-8
- Radiation-induced bystander effect
Aging is associated with highly reproducible DNA methylation (DNAm) changes, which may contribute to higher prevalence of malignant diseases in the elderly. In this study, we analyzed epigenetic aging signatures in 5,621 DNAm profiles of 25 cancer types from The Cancer Genome Atlas (TCGA). Overall, age-associated DNAm patterns hardly reflect chronological age of cancer patients, but they are coherently modified in a non-stochastic manner, particularly at CpGs that become hypermethylated upon aging in non-malignant tissues. This coordinated regulation in epigenetic aging signatures can therefore be used for aberrant epigenetic age-predictions, which facilitate disease stratification. For example, in acute myeloid leukemia (AML) higher epigenetic age-predictions are associated with increased incidence of mutations in RUNX1, WT1, and IDH2, whereas mutations in TET2, TP53, and PML-PARA translocation are more frequent in younger age-predictions. Furthermore, epigenetic aging signatures correlate with overall survival in several types of cancer (such as lower grade glioma, glioblastoma multiforme, esophageal carcinoma, chromophobe renal cell carcinoma, cutaneous melanoma, lung squamous cell carcinoma, and neuroendocrine neoplasms). In conclusion, age-associated DNAm patterns in cancer are not related to chronological age of the patient, but they are coordinately regulated, particularly at CpGs that become hypermethylated in normal aging. Furthermore, the apparent epigenetic age-predictions correlate with clinical parameters and overall survival in several types of cancer, indicating that regulation of DNAm patterns in age-associated CpGs is relevant for cancer development.
MeSH Terms
- Adult
- Aged
- Aged, 80 and over
- Aging
- CpG Islands
- DNA Methylation
- Databases, Genetic
- Epigenesis, Genetic
- Esophageal Neoplasms
- Female
- Humans
- Leukemia, Myeloid, Acute
- Male
- Middle Aged
- Mutation
- Neoplasms
- Prognosis
- Reference Values
Whales have 1000-fold more cells than humans and mice have 1000-fold fewer; however, cancer risk across species does not increase with the number of somatic cells and the lifespan of the organism. This observation is known as Peto's paradox. How much would evolution have to change the parameters of somatic evolution in order to equalize the cancer risk between species that differ by orders of magnitude in size? Analysis of previously published models of colorectal cancer suggests that a two- to three-fold decrease in the mutation rate or stem cell division rate is enough to reduce a whale's cancer risk to that of a human. Similarly, the addition of one to two required tumour-suppressor gene mutations would also be sufficient. We surveyed mammalian genomes and did not find a positive correlation of tumour-suppressor genes with increasing body mass and longevity. However, we found evidence of the amplification of TP53 in elephants, MAL in horses and FBXO31 in microbats, which might explain Peto's paradox in those species. Exploring parameters that evolution may have fine-tuned in large, long-lived organisms will help guide future experiments to reveal the underlying biology responsible for Peto's paradox and guide cancer prevention in humans.
MeSH Terms
- Animals
- Body Size
- Evolution, Molecular
- Gene Dosage
- Genes, Tumor Suppressor
- Humans
- Longevity
- Mathematical Concepts
- Mice
- Models, Genetic
- Multigene Family
- Mutation
- Neoplasms
- Risk Factors
- Species Specificity
Keywords
- Peto's paradox
- Wright–Fisher model
- algebraic model
- cancer
- evolution
- tumour suppression
Cancer cells are typically defined as infinitely proliferating, whereas normal cells (except stem cells) are considered as being programmed to become senescent. Our data show that this characterization is misleading. Multiplex Ligation-dependent Probe Amplification, TP53 sequencing, real-time polymerase chain reaction (PCR) for MUC1 and SCGB2A2 and immunocytochemistry, together with senescence detection assay and real-time microscopic observations were used to analyze primary neoplastic cells isolated from prostate, breast and colorectal tumors, as well as stable cancer cell lines (MCF7, MDA-MB-468, SW962, SK-MEL28, NCI-H1975 and NCI-H469). In all cases of primary cancer cell cultures, in vitro conditions rapidly revealed senescence in the majority of cells. Two out of six stable cancer cell lines did not exhibit any senescence-associated-β-Galactosidase-positive cells. Interestingly, four cell lines had small sub-populations of senescent cells (single SA-β-Gal-positive cells). Primary neoplastic cells from different types of cancer (prostate, breast, colon cancer) appear to be senescent in vitro. Apparently, cancer cell lines that have been used for many years in drug-testing analyses have constantly been misleading researchers in terms of the general sensitivity of cancer cells to senescence.
MeSH Terms
- Breast Neoplasms
- Cellular Senescence
- Colonic Neoplasms
- Female
- Humans
- MCF-7 Cells
- Male
- Mammaglobin A
- Mucin-1
- Prostatic Neoplasms
Keywords
- Senescence
- cancer cell line
- oncogene-induced senescence
- primary cell culture
- senescence-associated heterochromatin foci
- senescence-associated β-galactosidase
Variation in TP53 has been associated with cancer. The pro-allele of a TP53 polymorphism in codon 72 (rs1042522) has been associated with longevity. Recently, we showed that the same allele might be involved in preservation of glucose metabolism, body composition and blood pressure during ageing. Here, we assessed glucose tolerance and body composition in mice carrying the human polymorphism. Our data do not support the previous findings in humans, suggesting that this polymorphism does not play a major role in development of glucose metabolism and body composition during ageing. Alternatively, the mouse model may not be suitable to validate these rs1042522-associated traits up to the age tested.
MeSH Terms
- Aging
- Alleles
- Animals
- Body Composition
- Body Weight
- Glucose
- Glucose Tolerance Test
- Humans
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Models, Animal
- Polymorphism, Single Nucleotide
- Tumor Suppressor Protein p53
It is not yet known whether DNA methylation levels can be used to accurately predict age across a broad spectrum of human tissues and cell types, nor whether the resulting age prediction is a biologically meaningful measure. I developed a multi-tissue predictor of age that allows one to estimate the DNA methylation age of most tissues and cell types. The predictor, which is freely available, was developed using 8,000 samples from 82 Illumina DNA methylation array datasets, encompassing 51 healthy tissues and cell types. I found that DNA methylation age has the following properties: first, it is close to zero for embryonic and induced pluripotent stem cells; second, it correlates with cell passage number; third, it gives rise to a highly heritable measure of age acceleration; and, fourth, it is applicable to chimpanzee tissues. Analysis of 6,000 cancer samples from 32 datasets showed that all of the considered 20 cancer types exhibit significant age acceleration, with an average of 36 years. Low age-acceleration of cancer tissue is associated with a high number of somatic mutations and TP53 mutations, while mutations in steroid receptors greatly accelerate DNA methylation age in breast cancer. Finally, I characterize the 353 CpG sites that together form an aging clock in terms of chromatin states and tissue variance. I propose that DNA methylation age measures the cumulative effect of an epigenetic maintenance system. This novel epigenetic clock can be used to address a host of questions in developmental biology, cancer and aging research.
MeSH Terms
- Age Factors
- Aging
- Animals
- Blood Cells
- Brain
- Cell Line, Tumor
- Cellular Senescence
- Chromatin
- CpG Islands
- DNA Methylation
- Databases, Nucleic Acid
- Epigenesis, Genetic
- Gene Expression Regulation
- Humans
- Models, Biological
- Mutation
- Neoplasms
- Organ Specificity
- Pan troglodytes
- Progeria
- Receptors, Steroid
- Reproducibility of Results
- Stem Cells
Although the rescue of cellular senescence during ex vivo expansion of human-derived cardiac progenitor cells (hCPC) is critical for the application of autologous stem cell therapy in cardiovascular disease, the underlying molecular pathways during replicative senescence in hCPC have not been fully defined. Thus, we examined whether the regulation of mitogen-activated protein kinases activation could facilitate the recovery of human c-kit-positive hCPCs (hCPC(c-kit )) and whether senescence is reactive oxygen species (ROS)-dependent or -independent. To investigate the molecular pathways of replicative cellular senescence, we first evaluated cellular senescence in ex vivo-expanded hCPC(c-kit ) by using senescence-associated β-galactosidase (SA-β-gal) activity with enlarged cytoplasm and observed increased expression of cell senescence-related pivotal molecules, including TP53, cleavage Mdm2 (cMdm2), and Mdm2. Unexpectedly, we found that the extracellular signal-regulated kinase (ERK) was markedly activated in aged hCPC(c-kit ), with reduced proliferative activity. SA-β-gal activity and cytoplasm size in senescent hCPC(c-kit ) were significantly reduced, with reduced TP53 and cMdm2 expression after treatment with a specific ERK inhibitor (U0126). We examined whether the signaling in ERK inhibitory rescue of hCPC(c-kit ) senescence is ROS-dependent. Interestingly, the increased ROS level was not changed after treatment with a specific ERK inhibitor. Similarly, the increased expression levels of endogenous antioxidant enzymes, e.g., peroxiredoxin (Prdx)-1 and 2, in senescent hCPC(c-kit ) were not changed after treatment with a specific ERK inhibitor. From the above results, we conclude that the specific inhibition of ERK during cellular senescence might rescue bioactivities of senescent hCPC(c-kit ) in a ROS-independent manner.
MeSH Terms
- Cell Proliferation
- Cells, Cultured
- Cellular Senescence
- Extracellular Signal-Regulated MAP Kinases
- Humans
- MAP Kinase Signaling System
- Myocytes, Cardiac
- Proto-Oncogene Proteins c-kit
- Reactive Oxygen Species
- Signal Transduction
- Stem Cells
Keywords
- Cardiac progenitor cell
- ERK
- Peroxiredoxin
- Reactive oxygen species
- Replicative senescence
Radiotherapy is one of the well-established therapeutic modalities for cancer treatment. However, the emergence of cells refractory to radiation is a major obstacle to successful treatment with radiotherapy. Many reports suggest that inhibitors targeting the mechanistic target of rapamycin (MTOR) can sensitize cancer cells to the effect of radiation, although by which mechanism MTOR inhibitors enhance the efficacy of radiation toward cancer cells remains to be elucidated. Our studies indicate that a potent and persistent activation of autophagy via inhibition of the MTOR pathway, even in cancer cells where autophagy is occurring, can trigger premature senescence, cellular proliferation arrest. Combined treatment of MTOR inhibitor and radiation induce heterochromatin formation, an irreversible growth arrest and an increase of senescence-associated GLB1 (β-galactosidase) activity, which appear to result from a constant activation of TP53 and a restoration in the activity of retinoblastoma 1 protein (RB1)-E2F1. Thus, this study provides evidence that promoting cellular senescence via inhibition of the MTOR pathway may serve as an avenue to augment radiosensitivity in cancer cells that initiate an autophagy-survival mode to radiotherapy.
MeSH Terms
- Animals
- Autophagy
- Cell Proliferation
- Cellular Senescence
- Humans
- Neoplasms
- Radiation Tolerance
- Retinoblastoma Protein
- TOR Serine-Threonine Kinases
Keywords
- MTOR inhibitor
- RB
- autophagy
- cellular senescence
- irradiation
TP53's role as guardian of the genome diminishes with age, as the probability of mutation increases. Previous studies have shown an association between p53 gene mutations and cancer. However, the role of somatic TP53 mutations in the steep rise in cancer rates with aging has not been investigated at a population level. This relationship was quantified using the International Agency for Research on Cancer (IARC) TP53 and GLOBOCAN cancer databases. The power function exponent of the cancer rate was calculated for 5-y age-standardized incidence or mortality rates for up to 25 cancer sites occurring in adults of median age 42 to 72 y. Linear regression analysis of the mean percentage of a cancer's TP53 mutations and the corresponding cancer exponent was conducted for four populations: worldwide, Japan, Western Europe, and the United States. Significant associations (P ≤ 0.05) were found for incidence rates but not mortality rates. Regardless of the population studied, positive associations were found for all cancer sites, with more significant associations for solid tumors, excluding the outlier prostate cancer or sex-related tumors. Worldwide and Japanese populations yielded P values as low as 0.002 and 0.005, respectively. For the United States, a significant association was apparent only when analysis utilized the Surveillance, Epidemiology, and End Results (SEER) database. This study found that TP53 mutations accounts for approximately one-quarter and one-third of the aging-related rise in the worldwide and Japanese incidence of all cancers, respectively. These significant associations between TP53 mutations and the rapid rise in cancer incidence with aging, considered with previously published literature, support a causal role for TP53 according to the Bradford-Hill criteria. However, questions remain concerning the contribution of TP53 mutations to neoplastic development and the role of factors such as genetic instability, obesity, and gene deficiencies other than TP53 that reduce p53 activity.
MeSH Terms
- Adult
- Aged
- Body Mass Index
- Female
- Genetic Association Studies
- Genetic Predisposition to Disease
- Humans
- Incidence
- Linear Models
- Male
- Middle Aged
- Mutation
- Neoplasms
- SEER Program
- Tumor Suppressor Protein p53
Keywords
- TP53mutation
- aging
- cancer incidence
- cancer mortality
- population-based analysis
Exposure to herbal remedies containing the carcinogen aristolochic acid (AA) has been widespread in some regions of the world. Rare A→T TP53 mutations were recently discovered in AA-associated urothelial cancers. The near absence of these mutations among all other sequenced human tumors suggests that they could be biologically silent. There are no cell banks with established lines derived from human tumors with which to explore the influence of the novel mutants on p53 function and cellular behavior. To investigate their impact, we generated isogenic mutant clones by integrase-mediated cassette exchange at the p53 locus of platform (null) murine embryonic fibroblasts and kidney epithelial cells. Common tumor mutants (R248W, R273C) were compared with the AA-associated mutants N131Y, R249W, and Q104L. Assays of cell proliferation, migration, growth in soft agar, apoptosis, senescence, and gene expression revealed contrasting outcomes on cellular behavior following introduction of N131Y or Q104L. The N131Y mutant demonstrated a phenotype akin to common tumor mutants, whereas Q104L clone behavior resembled that of cells with wild-type p53. Wild-type p53 responses were restored in double-mutant cells harboring N131Y and N239Y, a second-site rescue mutation, suggesting that pharmaceutical reactivation of p53 function in tumors expressing N131Y could have therapeutic benefit. N131Y is likely to contribute directly to tumor phenotype and is a promising candidate biomarker of AA exposure and disease. Rare mutations thus do not necessarily point to sites where amino acid exchanges are phenotypically neutral. Encounter with mutagenic insults targeting cryptic sites can reveal specific signature hotspots.
MeSH Terms
- Amino Acid Substitution
- Animals
- Aristolochic Acids
- Biomarkers, Tumor
- Cell Line, Transformed
- Humans
- Iatrogenic Disease
- Mice
- Mutagens
- Mutation, Missense
- Plant Preparations
- Tumor Suppressor Protein p53
- Urethral Neoplasms
- Urothelium
Keywords
- Biomarkers
- Cancer Biology
- Cellular Senescence
- Molecular Cell Biology
- Mouse Genetics
- Mutagenesis Mechanisms
- Site-specific Recombination
- Suppressor Mutations
- Tumor Suppressor Gene
Recent studies have highlighted an apparently paradoxical link between self-renewal and senescence triggered by DNA damage in certain cell types. In addition, the finding that TP53 can suppress senescence has caused a re-evaluation of its functional role in regulating these outcomes. To investigate these phenomena and their relationship to pluripotency and senescence, we examined the response of the TP53-competent embryonal carcinoma (EC) cell line PA-1 to etoposide-induced DNA damage. Nuclear POU5F1/OCT4A and P21CIP1 were upregulated in the same cells following etoposide-induced G 2M arrest. However, while accumulating in the karyosol, the amount of OCT4A was reduced in the chromatin fraction. Phosphorylated CHK2 and RAD51/γH2AX-positive nuclear foci, overexpression of AURORA B kinase and moderate macroautophagy were evident. Upon release from G 2M arrest, cells with repaired DNA entered mitoses, while the cells with persisting DNA damage remained at this checkpoint or underwent mitotic slippage and gradually senesced. Reduction of TP53 using sh- or si-RNA prevented the upregulation of OCT4A and P21CIP1 and increased DNA damage. Subsequently, mitoses, micronucleation and senescence were all enhanced after TP53 reduction with senescence confirmed by upregulation of CDKN2A/P16INK4A and increased sa-β-galactosidase positivity. Those mitoses enhanced by TP53 silencing were shown to be multicentrosomal and multi-polar, containing fragmented and highly deranged chromosomes, indicating a loss of genome integrity. Together, these data suggest that TP53-dependent coupling of self-renewal and senescence pathways through the DNA damage checkpoint provides a mechanism for how embryonal stem cell-like EC cells safeguard DNA integrity, genome stability and ultimately the fidelity of self-renewal.
MeSH Terms
- Antineoplastic Agents, Phytogenic
- Aurora Kinase B
- Aurora Kinases
- Autophagy
- Cell Line, Tumor
- Cellular Senescence
- Checkpoint Kinase 2
- Cyclin-Dependent Kinase Inhibitor p16
- Cyclin-Dependent Kinase Inhibitor p21
- DNA Damage
- DNA Repair
- Embryonal Carcinoma Stem Cells
- Etoposide
- Female
- G2 Phase Cell Cycle Checkpoints
- Histones
- Humans
- Octamer Transcription Factor-3
- Ovarian Neoplasms
- Phosphorylation
- Protein-Serine-Threonine Kinases
- RNA Interference
- RNA, Small Interfering
- Rad51 Recombinase
- Tumor Suppressor Protein p53
- Up-Regulation
- beta-Galactosidase
Keywords
- DNA damage
- OCT4A/POU5F1
- TP53
- pluripotency
- self-renewal
- senescence
- tumor cells