R-Ketorolac Targets Cdc42 And Rac1 Gtpases And Alters Ovarian Tumor Cell Behaviors Critical For Invasion And Metastasis

Proceedings: AACR 106th Annual Meeting 2015; April 18-22, 2015; Philadelphia, PAOvarian cancer (OvCa) is the 5th leading cause of cancer death in women in the US with a 5-year survival rate of 44.6%. About 70% patients are diagnosed at advanced stages with intraperitoneal dissemination, therefore identifying intracellular targets and developing effective molecules to reduce tumor metastasis have great significance for ovarian cancer therapy. Cdc42 and Rac1 are small Rho GTPase and function as molecular switches of actin reorganization which are crucial to tumor cell adhesion, migration and invasion. In previous work, our group found Cdc42 and the constitutively active Rac1b are overexpressed in primary ovarian tumor tissues and ovarian cancer cell lines. Lead identification through a high-throughput screen combined with a computational shape homology approach, identified R-ketorolac as a Cdc42 and Rac1 regulator, an activity that is distinct from the anti-inflammatory, cyclooxygenase inhibitory activity of S-ketorolac. RhoA was unaffected by R-ketorolac. A bead-based flow cytometry assay identified R-ketorolac reduced Cdc42 and Rac1 GTPase nucleotide binding in vitro and inhibition was an allosteric mechanism of action. In cell-based assays, using Skov3ip cells, and in ascites-derived ovarian tumor cells, R-ketorolac was found to inhibit the activities of Cdc42 and Rac1 and their direct downstream effectors, the phosphorylation of p21-activated kinases (PAKs). R-ketorolac, but not S-ketorolac impeded Cdc42 mediated filopodia formation, measured based on both the length and numbers of filopodia in Skov3ip and primary OvCa cells. Cell behavior assays showed that R-ketorolac but not S-ketorolac strikingly inhibited cell adhesion, migration and invasion. In a xenograft mouse model a 50% reduction in tumor cell number and decreased total tumor burden was observed with R-ketorolac as compared to S-ketorolac treatment. Finally, in a ‘phase 0′ clinical study we found Cdc42 and Rac1 activities were reduced in a time-dependent manner after a single IV dose of racemic ketorolac treatment. In sum, we established R-ketorolac inhibition on Cdc42 and Rac1 activities and subsequent physiological consequences which are critical to tumor metastasis. Our findings provide the first demonstration of selective inhibition of Cdc42 and Rac1 GTPases by an FDA approved drug in humans.Citation Format: Yuna Guo, S. Ray Kenney, Larry A. Sklar, Tione Buranda, Tudor I. Oprea, Oleg Ursu, Sarah F. Adams, Teresa Rutledge, Carolyn Muller, Lesley Lomo, Laurie G. Hudson, Angela Wandinger-Ness. R-ketorolac targets Cdc42 and Rac1 GTPases and alters ovarian tumor cell behaviors critical for invasion and metastasis. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4044. doi:10.1158/1538-7445.AM2015-4044