2-Amino-N-{4-[5-(2-phenanthrenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl] -phenyl} acetamide (OSU-03012), a celecoxib derivative, directly targets p21-activated kinase

Leonardo M. Porchia, Marcy Guerra, Yu-Chieh Wang, Yunlong Zhang, Allan V. Espinosa, Motoo Shinohara, Samuel K. Kulp, Lawrence S. Kirschner, Motoyasu Saji, Ching Shih Chen, Matthew D. Ringel

Research output: Contribution to journalArticle

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p21-Activated kinases (PAKs) are regulators of cell motility and proliferation. PAK activity is regulated in part by phosphoinositide-dependent kinase 1 (PDK1). We hypothesized that reduced PAK activity was involved in the effects of 2-amino-N-{4-[5-(2-phenanthrenyl)-3-(trifluoromethyl)-1H-pyrazol-1- yl]-phenyl} acetamide (OSU-03012), a previously characterized PDK1 inhibitor derived from celecoxib. In three human thyroid cancer cell lines, OSU-03012 inhibited cell proliferation with reduced AKT phosphorylation by PDK1. OSU-03012 unexpectedly inhibited PAK phosphorylation at lower concentrations than PDK1-dependent AKT phosphorylation in two of the three lines. In cell-free kinase assays, OSU-03012 was shown to inhibit PAK activity and compete with ATP binding. In addition, computer modeling predicted a docking site for OSU-03012 in the ATP binding motif of PAK1. Finally, overexpression of constitutively activated PAK1 partially rescued the ability of motile NPA thyroid cancer cells to migrate during OSU-03012 treatment, suggesting that inhibition of PAK may be involved in the cellular effects of OSU-03012 in these cells. In summary, OSU-03012 is a direct inhibitor of PAK, and inhibition of PAK, either directly or indirectly, may be involved in its biological effects in vitro.

Original languageEnglish
Pages (from-to)1124-1131
Number of pages8
JournalMolecular Pharmacology
Issue number5
Publication statusPublished - 1 Nov 2007


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