Overexpression of βarrestin-2 in prostate cancer cells from African American males may contribute to aggressive tumor growth (P2075)

Abstract

Abstract Prostate cancer is the second leading cause of death in African American males. Its incidence is ~60% higher in African American males relative to Caucasian American males. More aggressive prostate cancer is attributed to cancer that is androgen independent resulting in lack of response to androgen replacement therapy. βarrestins are scaffold proteins that promote G protein coupled receptor desensitization and internalization. βarrestin-2 was recently shown to reduce Androgen Receptor expression in prostate cancer cells. The goal of this study was to determine the levels of expression of βarrestin-1/2 in prostate cancer cells from both racial groups and assess their roles in tumor aggressiveness. To that end, prostate cancer cell lines from African Americans (MDAPCa2B, E006AA), Caucasian Americans (LNCaP, PC3), and control (RWPE-1) were assayed for βarrestin-1/2 expression and cell proliferation. βarrestin-1 expression was elevated in all prostate cancer cell lines whereas βarrestin-2 overexpression was observed only in MDAPCa2B. Interestingly, MDAPCa2B showed greater cell proliferation relative to LNCaP and PC3. Suppression of βarrestin-2 in MDAPCa2B cells reduced cell proliferation and tumor growth in nude mice. Altogether the data indicate that 1) βarrestins modulate prostate cancer growth, and 2) overexpression of βarrestin-2 in prostate cancer cells from African Americans relative to Caucasian Americans may contribute to the prostate cancer disparity.