PAK1
Serine/threonine-protein kinase PAK 1 (EC 2.7.11.1) (Alpha-PAK) (p21-activated kinase 1) (PAK-1) (p65-PAK)
Publications[править]
PAK1 (RAC/CDC42-activated kinase 1) is the major oncogenic/ageing kinase, and its dysfunction extends the healthy lifespan of C. elegans by activating HSP16 gene. 15K is a highly cell-permeable 1,2,3-triazolyl ester of ketorolac that down-regulates both PAK1 and its down-stream COX-2 in R- and S-forms, respectively. 15K is 500-5,000 times more potent than ketorolac, an old pain-killer, inhibiting the growth of cancer cell lines with IC50 ranging 5-24 nM. Scores of natural and synthetic PAK1-blockers have been shown to extend the lifespan of small animals such as C. elegans, but none of them has been effective at nM levels. Thus, we examined in vivo effect of 15K at nM levels on the survival rate of C. elegans with or without heat-shock. Like the PAK1-deficient mutant, 15K (at 50 nM)-treated worm significantly lives longer, is far more heat-resistant and less productive (fertile) than the non-treated counterpart, with an increased expression of HSP16 gene. 15K has been proven to be among the most potent anti-cancerous and longevity-promoting PAK1-blockers, and therefore has a potential to treat a variety of solid tumours without severe side effect.
MeSH Terms
- Animals
- Caenorhabditis elegans
- Caenorhabditis elegans Proteins
- Down-Regulation
- Gene Expression Regulation, Enzymologic
- Hot Temperature
- Ketorolac
- Longevity
- Molecular Structure
- Triazoles
- p21-Activated Kinases
Keywords
- 1,2,3-triazolyl ester
- C. elegans
- Ketorolac
- PAK1
- anti-cancer
- lifespan
PAK family kinases are RAC/CDC42-activated kinases that were first found in a soil amoeba 4 decades ago, and 2 decades later, were discovered in mammals as well. Since then at least 6 members of this family have been identified in mammals. One of them called PAK1 has been best studied so far, mainly because it is essential not only for malignant cell growth and metastasis, but also for many other diseases/disorders such as diabetes (type 2), AD (Alzheimer's disease), hypertension, and a variety of inflammatory or infectious diseases, which definitely shorten our lifespan. Moreover, PAK1-deficient mutant of C. elegans lives longer than the wild-type by 60%, clearly indicating that PAK1 is not only an oncogenic but also ageing kinase. Thus, in theory, both anti-oncogenic and longevity-promoting activities are among the "intrinsic" properties or criteria of "clinically useful" PAK1-blockers. There are a variety of PAK1-blocking natural products such as propolis and curcumin which indeed extend the healthy lifespan of small animals such as C. elegans by inducing the autophagy. Recently, we managed to synthesize a series of potent water-soluble and highly cell-permeable triazolyl esters of COOH-bearing PAK1-blockers such as Ketorolac, ARC (artepillin C) and CA (caffeic acid) via "Click Chemistry" that boosts their anti-cancer activity over 500-fold, mainly by increasing their cell-permeability, and one of them called 15K indeed extends the lifespan of C. elegans. In this mini-review we shall discuss both synthetic and natural PAK1-blockers, some of which would be potentially useful for cancer therapy with least side effect (rather promoting the longevity as well).
MeSH Terms
- Animals
- Antineoplastic Agents
- Click Chemistry
- Drug Discovery
- Humans
- Longevity
- Neoplasms
- Protein Kinase Inhibitors
- p21-Activated Kinases
Keywords
- C. elegans
- Cancer
- Click Chemistry
- Longevity
- PAK1
- Propolis
Propolis from different areas has been reported to inhibit oncogenic/aging kinase PAK1, which is responsible for a variety of conditions, including cancer, longevity, and melanogenesis. Here, a crude extract of Okinawa propolis (OP) was tested against PAK1 activity, Caenorhabditis elegans (C. elegans) longevity, melanogenesis, and growth of cancer cells. We found that OP blocks PAK1 and exhibits anticancer activity in the A549 cell (human lung cancer cell) line with IC50 values of 6 μg/mL and 12 μg/mL, respectively. Most interestingly, OP (1 μg/mL) significantly reduces reproduction and prolongs the lifespan of C. elegans by activating the HSP-16.2 gene, as shown in the PAK1-deficient strain. Furthermore, OP inhibits melanogenesis in a melanoma cell line (B16F10) by downregulating intracellular tyrosinase activity with an IC50 of 30 μg/mL. Our results suggest that OP demonstrated a life span extending effect, C. elegans, anticancer, and antimelanogenic effects via PAK1 inactivation; therefore, this can be a potent natural medicinal supplement against PAK1-dependent diseases.
MeSH Terms
- Animals
- Caenorhabditis elegans
- Cell Proliferation
- Humans
- Japan
- Longevity
- Melanins
- Neoplasms
- Propolis
- p21-Activated Kinases
Keywords
- Caenorhabditis elegans
- Okinawa propolis
- PAK1
- cancer
- longevity
- melanogenesis
The p21-activated kinase 1 (PAK1) is emerging as a promising therapeutic target, and the search for blockers of this oncogenic/aging kinase would be potentially useful for the treatment of various diseases/disorders in the future. Here, we report for the first time the anti-PAK1 activity of compounds derived from three distinct Okinawa plants. 5,6-Dehydrokawain (DK) and dihydro-5,6-dehydrokawain (DDK) from alpinia inhibited directly PAK1 more strongly than mimosine and mimosinol from leucaena. Cucurbitacin I isolated from bitter gourd/melon also exhibited a moderate anti-PAK1 activity. Hispidin, a metabolite of DK, strongly inhibited PAK1 with the IC50 = 5.7 μM. The IC50 of three hispidin derivatives (H1-3) for PAK1 inhibition ranges from 1.2 to 2.0 μM, while mimosine tetrapeptides [mimosine-Phe-Phe-Tyr (MFFY) and mimosine-Phe-Trp-Tyr (MFWY)] inhibit PAK1 at nanomolar level (IC50 of 0.13 and 0.60 μM, respectively). Thus, we hope these derivatives of hispidin and mimosine could be used as potential leading compounds for developing far more potent anti-PAK1 drugs which would be useful for clinical application in the future.
MeSH Terms
- Aging
- Humans
- Japan
- Neoplasms
- Plants, Medicinal
- Protein Kinase Inhibitors
- p21-Activated Kinases
Over 35 years research on PAKs, RAC/CDC42(p21)-activated kinases, comes of age, and in particular PAK1 has been well known to be responsible for a variety of diseases such as cancer (mainly solid tumors), Alzheimer's disease, acquired immune deficiency syndrome and other viral/bacterial infections, inflammatory diseases (asthma and arthritis), diabetes (type 2), neurofibromatosis, tuberous sclerosis, epilepsy, depression, schizophrenia, learning disability, autism, etc. Although several distinct synthetic PAK1-blockers have been recently developed, no FDA-approved PAK1 blockers are available on the market as yet. Thus, patients suffering from these PAK1-dependent diseases have to rely on solely a variety of herbal therapeutics such as propolis and curcumin that block PAK1 without affecting normal cell growth. Furthermore, several recent studies revealed that some of these herbal therapeutics significantly extend the lifespan of nematodes (C. elegans) and fruit flies (Drosophila), and PAK1-deficient worm lives longer than the wild type. Here, I outline mainly pathological phenotypes of hyper-activated PAK1 and a list of herbal therapeutics that block PAK1, but cause no side (harmful) effect on healthy people or animals.
MeSH Terms
- Animals
- Antineoplastic Agents, Phytogenic
- Communicable Diseases
- Curcumin
- Humans
- Inflammation
- Longevity
- Neoplasms
- Phytotherapy
- Plants, Medicinal
- Propolis
- p21-Activated Kinases
Keywords
- AIDS
- Alzheimer's disease
- King of Bitters
- PAK1
- Thunder god vine
- cancer
- curcumin
- diabetes
- longevity
- neurofibromatosis
- propolis
- tuberous sclerosis
There is an increasing evidence that the oncogenic kinase PAK1 is responsible not only for malignant transformation, but also for several other diseases such as inflammatory diseases (asthma and arthritis), infectious diseases including malaria, AIDS, and flu, as well as a series of neuronal diseases/disorders (neurofibromatosis, tuberous sclerosis, Alzheimer's diseases, Huntington's disease, epilepsy, depression, learning deficit, etc.) which often cause premature death. Interestingly, a few natural PAK1-blockers such as curcumin, caffeic acid (CA) and rosmarinic acid (RA) extend the lifespan of the nematode Caenorhabditis elegans or fruit flies. Here, to explore the possibility that C. elegans could provide us with a quick and inexpensive in vivo screening system for a series of more potent but safe (non-toxic) PAK1-blocking therapeutics, we examined the effects of PAK1-deficiency or down-regulation on a few selected functions of this worm, including reproduction, expression of HSP16.2 gene, and lifespan. In short, we found that PAK1 promotes reproduction, whereas it inactivates HSP16.2 gene and shortens lifespan, as do PI-3 kinase (AGE-1), TOR, and insulin-like signalling /ILS (Daf-2) in this worm. These findings not only support the "trade-off" theory on reproduction versus lifespan, but also suggest the possibility that the reduced reproduction (or HSP16.2 gene activation) of this worm could be used as the first indicator of extended lifespan for a quick in vivo screening for PAK1-blockers.
MeSH Terms
- Animals
- Caenorhabditis elegans
- Caenorhabditis elegans Proteins
- Caffeic Acids
- Down-Regulation
- Green Fluorescent Proteins
- Heat-Shock Proteins
- Longevity
- Phenylethyl Alcohol
- Phenylpropionates
- Protein Kinase Inhibitors
- Recombinant Fusion Proteins
- Reproduction
- Signal Transduction
- p21-Activated Kinases