Pathogenic Roles of PAK1 Including Oncogenesis and Ageing
Keywords:
discovered around1994.The ability of PAK1 to be directly activated in vitro ancient class.
the cytoskeleton.
by Rac1 and Cdc42 led to the notion that such protein kinases may
Jonathan Chernoff, Fox Chase Cancer Center, Philadelphia, USA, Several lab groups have contributed to the discovery of p21 (RAC/CDC42)-activated kinases (PAKs) and to the elucidation of their cellular functions. Of the two PAK families, Group A PAKs (PAK1, -2, and -3) are the best studied, but this situation is gradually changing, and models of the signaling properties of both group A and group B PAKs have emerged. These models have been inferred primarily via the identification of PAK substrates, including those that are involved in the activation of the ERK, AKT, Aurora, and β-catenin pathways. In this presentation, I will discuss the roles of Group A and B PAKs in three cancer models and discuss the potential use of PAK-based small molecule and peptide PhD and M.D. (in Biochemisty) from Mount Sinai School of Medicine, New York, in 1984 Resident, at University Health Center of Pittsburgh (1984-1987), Clinical Fellow at Beth Israel Hospital, Boston (1988-1990) and Postdoc at Harvard Uni (1988-1991). Joining the Fox Chase Cancer Center (FCCC), Philadelphia in 1991. Currently, Professor, Chief Scientific Officer and Deputy Director, Stanley P. Reimann Chair in Oncology Research (FCCC).
Fox Chase Cancer Center, Philadelphia, USA E-mail: Jonathan.chernoff@fccc.edu
inhibitors as therapeutic agents in cancer.
Dr. Chernoff is a gentleman in white shirts around the middle.
Gunda Georg, Department of Medicinal Chemistry, University of Minnesota, USA, Pancreatic cancer is the fourth leading cause of cancer related deaths in the United States, with a 5-year survival rate of around 10%. Despite significant research in the treatment of pancreatic cancer, the survival rate of patients with the disease has not significantly improved over the past few decades, mainly because 90% of pancreatic cancers are resistant to conventional chemotherapeutics (chemos, DNA poisons) such as gemcitabine. The low survival rate of patients with pancreatic cancer points towards a need for entirely different therapeutic strategies. Interestingly, the major reason for chemo-resistance is abnormal activation of the major oncogenic kinase PAK1. In fact natural PAK1-blockers such as propolis cure effectively even terminal pancreatic cancers. However, many of these PAK1-blockers are water-insoluble, and therefore their bioavailability is rather poor. Minnelide is a water-soluble phosphorylated form of a water-insoluble natural PAK1-blocker called Triptolide, and currently investigated in Phase I and Phase II clinical trials for the treatment of pancreatic, other gastrointestinal cancers and AML. The PhD (in Medicinal Chemistry) from Philipps University Marburg, Germany in 1980 Postdoctoral, at Philipps University Marburg (1981) and University of Ottawa, Canada (1982). Currently Professor and Head at Department of Medicinal Chemistry at University of Minnesota, USA, and Director of Institute for Therapeutics Discovery and Development (ITDD).
Ref: R. Chugh, V.Sangwan, SP Patil, V. et al. A preclinical evaluation of Minnelide as a therapeutic agent pancreatic cancer. Sci Tensl Med.;
Department of Medicinal Chemistry, University of Minnesota, USA E-mail: georg@umn.edu
discovery of Minnelide and its preclinical development will be discussed.
4(156): 156ra139 (2012).
Hiroshi Maruta, PAK Research Center, Melbourne, Australia, E-mail: Maruta20420@yahoo.co.jp Back in 1994, 17 years after we discovered in amoeba the first member of PAK family (RAC/CDC42-activated kinases) that activates myosin I ATPase by heavy chain phosphorylation, the first “mammalian” PAKs were cloned by Ed Manser’s team in Singapore. Among the 6 mammalian PAKs, PAK1 turned out to be the major “pathogenic” kinase responsible for a wide variety of diseases such as cancers, infectious/inflammatory diseases, AD (Alzheimer’s disease), hypertension as well as ageing and melanogenesis. Thus, our team spent more than 2 decades to identify or develop a series of PAK1-blockers (natural or synthetic) for treatment of these diseases/disorders. Propolis (bee-product) is among the first natural PAK1-blockers that turned out to be useful for cancer therapy and promoting the longevity. However, PAK1-blocking ingredients in Propolis such as Artepillin C (ARC) and Caffeic Acid (CA) are COOH-bearing compounds whose cell-permeability is rather poor. Thus, we first managed to boost their cell-permeability 100-400 times by esterization with a water-soluble 1, 2, 3 triazolyl alcohol via Click Chemistry (CC). Eventually we could boost both anti-cancer and anti-PAK1 activity of an old COOH-bearing pain-killer (Ketorolac) via a similar CC approach by over 500 times. The resulting ester called “15K” extends the healthy lifespan of C. elegans by 30% at 10-100 nM, and suppresses both growth and metastasis of chemo-resistant human pancreatic cancer xenografts in mice with IC50 below 0.1 mg/kg/day with no side effect. Thus, we are NIH (1973-1980), Max-Planck-Institute in Munich (1980-1984), Yale and UCSD (1985-1987),Ludwig Institute for Cancer Research in Melbourne (1988-2006), PAK Research Center in Melbourne (2007-present).
BC. Nguyen, H. Takahashi, Y. Uto, MD Shahinozzaman, S. Tawata, H. Maruta. 1,2,3-Triazolyl ester of Ketorolac: A “Click Chemistry”-based highly potent PAK1-blocking cancer-killer. Eur J Med Chem.; 126: 270-276 (2016).
PAK Research Center, Melbourne, Australia
intending to start its clinical trials ASAP.
PhD (in pharmaceutical sciences) from Tokyo University in 1972
Laurie G. Hudson, University of New Mexico, USA, E-mail: Lhudson@salud.unm.edu An old pain-killer called Ketorolac is a 1:1 racemic mixture of S- and R-forms. The S-form is the active component for its FDA indication in pain management that selectively inhibits cyclooxygenases such as COX-2. The biological function of R-form has remained unknown for decades, but recently recognized as a direct inhibitor of GTPases called Rac1 and Cdc42. Rac1 activity and expression are frequently elevated in tumors and a recent meta-analysis of 1,793 patients in 14 studies concluded that Rac1 expression was a poor prognostic indicator across cancers. Our analysis of the 298 Stage III and IV high-grade serous ovarian cancer (HGSOC) patients with outcomes data in The Cancer Genome Atlas (TCGA) demonstrates that high total RAC1 (but not CDC42) mRNA expression is associated with worse outcomes. R-ketorolac inhibits the serum /EGF-dependent Rac1 and Cdc42 activation, thereby inactivating their down-streams such as PAK1. R-ketorolac, but not S-ketorolac, inhibits Rac1-dependent cellular functions in cancer cell lines and primary ovarian tumor cells isolated from patient ascites fluids including inhibition of growth factor-stimulated formation of filopodia, cell adhesion to fibronectin and type I collagen, development of invadopodia, , R-ketorolac decreases ovarian tumor cell implantation in the omentum, decreases tumor growth and increases survival of mice in a xenograft study using OVCAR8 ovarian cancer cells. These preclinical findings suggest that R-ketorolac may have beneficial actions in human ovarian cancer that could account for the reported improved patient outcomes associated with peri-operative ketorolac use. An initial clinical study of ovarian cancer patients was conducted following administration of racemic ketorolac for its FDA- approved indication in post-operative analgesia. Ketorolac was distributed to the peritoneum within 1 hour after IV administration, and at 6 hours, ketorolac levels in the peritoneal fluids were nearly equivalent to those present in the serum. At each of the time points (1, 6, and 24 h), peritoneal fluids were enriched in R-ketorolac compared to the S-form. R-ketorolac achieved concentrations in the peritoneal fluids at or above (μM levels) for Rac1 and Cdc42 and resulted in time-dependent inhibition of Rac1 and Cdc42 in cells retrieved from the peritoneal compartment. R-ketorolac predominates in the peritoneal fluids and the S-form is virtually undetectable at 24 hours, indicating that the R-form permeable analogs such as 15K (1,2,3-triazolyl ester) are potential therapeutics for a wide variety of cancers.
Postdoc at UCSD (1985-1990). Assistant Prof at Northwestern University School of Medicine (1990-1997). Asssociate Prof. at UNM Health Sciences Ctr (1997-2003). Professor at Pharmaceutical Sciences, College of Pharmacy, UNM Health Sciences Ctr (2003-present).
University of New Mexico, USA
and tumor cell migration. In vivo the IC is bioactive and accounts for the observed inhibition of the GTPases in vivo.
Ph. D. (Pharmacology/Toxicology) from Harvard University in 1985
We propose that the COOH-bearing Ketorolac and its highly cellrd
Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai, UAE Thomas E. Adrian, Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai, Among our anti-cancer marine compounds the most potent is a PAK1-inhibiting sulfated saponin called frondoside A (FRA) from a . FRA inhibits the growth of multiple cancer cell lines, including pancreas and lungs with IC against PAK-1. FRA inhibits tumor cell migration, invasion, growth below 1 mg/kg/day. Additionally, at low concentrations FRA acts as an immune-stimulant of cell-based immunity without significant effect on humoral immunity and blocks multidrug resistance by inhibiting P-glycoprotein activity. FRA has no effect on The anti-cancer effects of a more potentPAK1-blocker called 15K (highly cell-permeable ester of Ketorolac) were also tested. 15K xenograft model with gemcitabine-resistant human pancreatic cancer cell lines (AsPC-1 and BxPC-3) expressing luciferase in athymic mice.
day, 15K suppressed total burden (growth) of both AsPC-1 and BxPC-3 tumors (measured as radians/sec) with IC 15K also reduced their metastasis in a similar manner. However, 15K had no effect on body weight or hematological parameters PhD (Biochem/Physiol) Royal Postgraduate Medical School (Imperial College), London in 1980 RPMS, London (1980-1985); Yale (1985-1988); Prof. and Director of Cancer Research, Creighton, Omaha (1988-2001); Prof. and Director of GI Cancer Research, Northwestern, Chicago (2001-2006); Prof and Chair UAEU (2006-2018); Prof and Chair of Research and Grad Studies,
UAE, E-mail: Thomas.Adrian@mbru.ac.ae
sea cucumber, Cucumaria frondosa 0.5–1 μM, similar to the IC angiogenesis with IC body weight, hematological parameters or on hepatic/renal function.
the growth of several pancreatic cancer cell lines with IC ranging 41-88 nM th By the 28 kg/day, i.p.
even at daily dose 5 mg/kg.
ranging in vivo, development of metastases and inhibited in vitro. The effect of 15K was further investigated in an orthotopic below 0.1mg/
Department of Surgery, University of Melbourne, Austin Health, Heidelberg, Australia Hong He, Dept. of Surgery, University of Melbourne, Austin Health, Heidelberg, Australia, Immunotherapies have not yielded significant clinical benefits for pancreatic ductal adenocarcinoma (PDA) because of the existence of an immunosuppressive tumor microenvironment (TME) characterised by a desmoplastic stroma containing infiltrated immune cells and activated pancreatic stellate cells (PSCs). Inhibition of PAK1 (RAC/CDC42-activated kinase 1) suppressed the growth of PDA and PSCs, and up-regulated the tumor immune response. The aim of this study was to investigate the involvement of PAK1 in anti-tumor immunity. PAK1 expression, PSC activation, and intra-tumoral T cells, were analysed in murine and human PDA samples by immunohistochemistry and FACS. The correlation of PAK1 to PSC activation, intra-tumoral T cells and survival was calculated. The mechanism by which PAK1 affected antitumor immunity was investigated by measuring cancer cell survival after co-culturing with activated lymphocytes. In PDA patients low PAK1 T cell/PAK1 ratios correlated with longer overall survival. In a murine PDA model PAK1 T cells, inhibited PSCs activation and extended survival. Inhibition of PAK1 reduced PSC- stimulated PDA cell proliferation, blocked PSC-mediated protection of PDA cells from killing by cytotoxic lymphocytes and decreased basal and PSC-stimulated PD-L1 expression in PDA cells, which further sensitized PDA cells to cytotoxic lymphocytes.
down-regulation of intrinsic and PSC-stimulated PD-L1 expression. Thus, inexpensivePAK1-blocking chemicals could replace the so-called immune check-point therapeutics (monoclonals) for the improved treatment of PDA.
M.D from Beijing Medical University (China) in 1987, and Ph.D. (in Molecular Biology) from University of Melbourne in 1994. Joining Ludwig Institute for Cancer Research (Melbourne Branch) as a postdoc in 1994. Joining the Department of Surgery of University of Melbourne (within Austin Health) in 2003, and currently a Senior Research Scientist at the above. Her major expertise is in roles of PAKs in cancers and Wang K, Zhan Y, Huynh N, et al. Inhibition of PAK1 suppresses pancreatic cancer by stimulation of anti-tumour immunity through down-
E-mail: Hong.he@unimelb.edu.au
+ expression, low activation of PSC and high CD8 + + knockout increased intra-tumoral CD4 and CD8 + + anti-tumor immunity by increasing intra-tumoral CD4 and CD8 T cells, and by sensitizing PDA cells to killing by cytotoxic lymphocytes via
regulation of PD-L1. Cancer Lett. 2020; 472: 8-18.
Inhibition of PAK1 stimulates
Maria Diakonova, University of Toledo, OH, USA, E-mail: mdiakon@utnet.utoledo.edu In 2007, we demonstrated that PAK1 is a substrate of the Tyr-kinase JAK2 which is activated by hormone/cytokine prolactin (PRL). JAK2 by JAK2. This phosphorylation enhances both PAK1 kinase activity and its ability to form protein/protein interactions (scaffolding properties of PAK1). We found that pTyr-PAK1 facilitates PRL-dependent motility of breast cancer cells via at least two mechanisms: (1) formation of paxillin/GIT1/ βPIX /pTyr-PAK1 complexes resulting in increased adhesion turnover, and phosphorylation of actin-binding protein filamin A. Increased adhesion turnover is the basis for cell migration and phosphorylated filamin A stimulates the kinase activity of PAK1 to facilitate cell motility. (2) pTyr-PAK1 also stimulates invasion of breast cancer cells in response to PRL and 3D-collagen IV by stimulating both transcription and secretion of MMP-1 and MMP-3 in a MAPK-dependent manner. We indeed confirmed that that pTyr-PAK1 enhances breast tumor growth and metastasis in a xenograft mouse model. Overall, our data illustrate the complex interaction between prolactin and the cell microenvironment in breast cancer cells and suggest a pivotal role for\ prolactin/pTyr-PAK1 signaling in breast cancer metastasis.
Although PRL and estrogen exert independent effect on breast cancer cells, there is cross-talk between them leading to synergetic breast cancer progression. We recently found that pTyr-PAK1is a common node for estrogen- and PRL-dependent pathways. An Estrogen-activated Tyr-kinase ETK directly phosphorylates PAK1 on Tyr153. Furthermore Estrogen-activated PKA phosphorylates Ser305 on estrogen receptor (ERα), while PRL-activated pTyr-PAK1 phosphorylates the same site of ERα, implying that maximal ERα phosphorylation is achieved when cells are exposed to both PRL and estrogen. However, anti-estrogen therapy by Tamoxifen (TAM) targets only the estrogen component. Notably, ERα phosphorylation at Ser 305 was implicated in TAM-resistance. Thus, a combination of JAK2-inhibitor and ETK-inhibitor that eventually blocks PAK1 would be a better approach for breast cancer therapy.
PhD (Cell Biology) from the Institute of Cytology Russian Academy of Science (St.-Petersburg, Russia) in 1993 Postdoc at the EMBL (Heidelberg, Germany) and the University of Michigan (Ann Arbor, MI, USA) (1995-2002). Research Assistant Professor at the University of Michigan (2002-2006). Assistant, Associate and Professor at the University of Toledo, OH (2006-present).
University of Toledo, OH, USA
phosphorylates PAK1 atTyr 153, 201 and 285 in vivo and in vitro. We identified Tyr285 as a site of PRL-dependent phosphorylation of PAK1
Wade Clapp, Indiana University School of Medicine, Indianapolis, USA, E-mail: dclapp@iu.edu Neurofibromatosis Type II (NF2) is an autosomal dominant cancer predisposition syndrome in which germline haplo-insufficiency at the NF2 gene confers a greatly increased propensity for tumor development arising from tissues of neural crest derived origin. NF2 encodes the tumor suppressor, Merlin, and its biochemical function is incompletely understood. One well established function of Merlin is as a negative regulator of the kinase PAK1. In these studies we explore the role of PAK1 in Merlin deficient Schwann cells. We demonstrate that not only PAK1 and but also PAK2 are hyper-activated in Merlin deficient murine schwannoma and that genetic ablation of PAK1 alone, but not PAK2, ameliorates tumor formation in a genetically engineered mouse model (GEMM) of NF2. Moreover, germline genetic deletion of PAK1 was well tolerated while conditional deletion of PAK2 in Schwann cells resulted in significant morbidity and mortality. These data support the further development of PAK1 specific inhibitors and the therapeutic targeting of PAK1 in vestibular schwannoma and argue that PAK1 and PAK2 play Postdoc training (1982-1991) at Indiana University (School of Medicine) and Case Western Reserve University. Joining Indiana University School of Medicine in 1991. Currently Professor (and Director of Tumor Microenvironment Program, IU Simon Cancer Center) at Indiana
Indiana University School of Medicine, Indianapolis, USA (Presented by Dr. Jonathan Chernoff on behalf of Dr. Clapp)
clearly distinct (non-redundant) roles in Schwann cells.
M.D. from Indiana University School of Medicine in 1982
th
Department of Chemical Biology, Rutgers, the State University of New Jersey, USA Audrey Minden, Dept. of Chemical Biology. Rutgers, the State University of New Jersey, USA, Triple negative breast cancer (TNBC) is difficult to treat due to lack of druggable targets. The kinase PAK4 is often highly expressed in TNBC cells. We previously found that inhibition of PAK4 with either siRNA or theanti-PAK4 drug KPT-9274 suppresses the growth of TNBC cells. In order to understand better how blocking PAK4 inhibits TNBC cell growth, we carried out RNA sequencing of TNBC cells treated with KPT-9274. As a result, we identified Rictor as a key target that is suppressed in the KPT-9274 treated cells. Rictor is a component of TORC2, a complex formed with the oncogenic Ser/Thr kinase TOR (target of rapamycin). TOR is important for controlling cell growth and metabolism, while PAK4 is associated with cell growth, survival, and migration. Our results suggest a new mechanism by which PAK4 inhibition may block PhD (in Genetics) from University of Illinois at Chicago, College of Medicine in 1992 Post doc at Dept. of Pharmacology, UCSD (1992-1996). Joining Columbia University, New York in 1996. Associate Professor: Dept. of Biological Sciences, Columbia University (2001-2006). Associate Professor at Susan Lehman Cullman Laboratory for Cancer Research, Dept. of Chemical Biology. Rutgers, the State University of New Jersey (2006-present).
Cordover E, Wei J, Patel C, et al. KPT-9274, an inhibitor of PAK4 and NAMPT, leads to down regulation of mTORC2 in triple negative breast
E-mail: aminden@pharmacy.rutgers.edu
the growth of cancer cells, by down-regulating TORC2 signaling.
cancer cells. Chem Res Toxicol. 2019 Dec 26.