title: Modulation of p21-activated kinase 1 alters the behavior of renal cell carcinoma.
abstract: The p21-activated kinase 1 (Pak1) is a serine/threonine kinase whose activity is regulated by both Rho GTPases and AGC kinase family members. It plays a role in cytoskeletal remodeling and cell motility as well as cell proliferation, angiogenesis, tumorigenesis and metastasis. An involvement of Pak1 in renal cell carcinoma (RCC), which remains highly refractory to chemotherapy and radiotherapy, remains to be investigated. Pak1 expression, phosphorylation and kinase activity were examined in RCC cell lines and human tissue from normal and renal carcinoma. We report increased Pak1 expression and constitutive activity in the membrane and nucleus but not the cytoplasm of resected human RCC. To study a role for Pak1 in RCC, we developed 786-0 clones that expressed either a kinase-active Pak1L83,L86 2 different Pak1 dominant negative mutants, Pak1R299 and Pak1L83,L86,R299 or Pak1 siRNA. The expression of Pak1L83,L86 increased 786-0 proliferation, motility and anchorage independent growth, while the dominant negative mutants and Pak1 siRNA abrogated these effects. In addition, Pak1L83,L86 conferred resistance to 5-fluorouracil with a 40%+/-10% increase in cell viability. Conversely, Pak1L83,L86,R299, Pak1R299 and Pak1 siRNA conferred sensitivity with a 65.2%+/-5.5%, 69.2%+/-3.3% and 73.0%+/-8.4% loss in viability, respectively. Finally, Pak1 plays a role in renal tumor growth in vivo. Only 33% of mice developed tumors in the Pak1L83,L86,R299 group and no tumors developed from Pak1R299 cell challenge. Together these findings point to Pak1 as an exciting target for therapy of renal cancer, which remains highly refractory to existing treatments.
authors.affiliation: Cork Cancer Research Center, Leslie C. Quick Jnr. Cancer Laboratories, Bioscience Institute and Mercy University Hospital, Cork, Ireland.
authors.forename: Gerald C
authors.initials: GC
authors.lastname: O'Sullivan
authors.affiliation: Cork Cancer Research Center, Leslie C. Quick Jnr. Cancer Laboratories, Bioscience Institute and Mercy University Hospital, Cork, Ireland.
authors.forename: Mark
authors.initials: M
authors.lastname: Tangney
authors.affiliation: Cork Cancer Research Center, Leslie C. Quick Jnr. Cancer Laboratories, Bioscience Institute and Mercy University Hospital, Cork, Ireland.
authors.forename: Garret
authors.initials: G
authors.lastname: Casey
authors.affiliation: Department of Pharmacology and Therapeutics, Cork University Hospital and National University of Ireland, Cork, Ireland.
authors.forename: Monica
authors.initials: M
authors.lastname: Ambrose
authors.affiliation: Department of Medicine, Cork University Hospital and National University of Ireland, Cork, Ireland.
authors.forename: Aileen
authors.initials: A
authors.lastname: Houston
authors.affiliation: Cork Cancer Research Center, Leslie C. Quick Jnr. Cancer Laboratories, Bioscience Institute and Mercy University Hospital, Cork, Ireland.|Department of Pharmacology and Therapeutics, Cork University Hospital and National University of Ireland, Cork, Ireland.
authors.forename: Orla P
authors.initials: OP
authors.lastname: Barry
mesh_terms: D000634:Aminoquinolines / Q000633:toxicity; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002292:Carcinoma, Renal Cell / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D049109:Cell Proliferation; D004789:Enzyme Activation; D005472:Fluorouracil / Q000633:toxicity; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051379:Mice; D009154:Mutation / Q000235:genetics; D010766:Phosphorylation; D015996:Survival Rate; D023041:Xenograft Model Antitumor Assays; D054462:p21-Activated Kinases / Q000235:genetics / Q000378:metabolism*
chemical_list: D000634:Aminoquinolines; C041715:6-anilino-5,8-quinolinedione; C515903:PAK1 protein, human; D054462:p21-Activated Kinases; D005472:Fluorouracil