Abstract LB-16: Inhibition of RalA as a novel strategy for targeting ovarian cancer

Abstract Abstract: The Ral (Ras like) GTPase guanyl nucleotide-binding proteins, RalA and RalB are direct effectors of pro-oncogene Ras. RalA and RalB are implicated in tumorigenesis and play distinct roles in mediating carcinogenesis. The critical role of RalA in the initiation and progression of ovarian cancer is entirely unclear. Here, we report that RalA is overactivated in human ovarian cancer cells and human ovarian cancer tissues. The RalA downstream effectors (RalBP-1 and CDC42) and the regulators (GalGDS, PP2A Aα and β, as well as Aurora Kinase) that modulate RalA activation during the post-translational process were found to be de-regulated in ovarian cancer cells. ShRNA-mediated knockdown of RalA inhibited ovarian cancer cell proliferation and invasion. Geranyl-Geranyl transferase inhibitors (GGTI-2147) or Aurora Kinase Inhibitor (AKI) that inhibit RalA activation at post-translational levels suppressed ovarian cancer cell growth and invasion in-vitro. Additionally, subcutaneous (SC) mouse model with these two inhibitors also showed effective inhibition of tumor growth in-vivo. Therefore, RalA is a key player in the biology and dispersal of ovarian cancer cells and is a promising target for the development of novel therapeutics. To the best of our knowledge, the role of RalA in ovarian cancer tumorigenesis has not been documented before, therefore our strategy in targeting RalA for treatment of ovarian cancer merits highly in terms of novelty. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-16. doi:10.1158/1538-7445.AM2011-LB-16