Abstract 1022: The role of dopamine signaling in prostate cancer disparities

Abstract

Abstract Prostate cancer is the second leading cause of cancer-related deaths among men in western countries. Majority of prostate tumors often evolves as metastatic castration-resistant prostate cancer (CRPC) following hormonal therapy. Metastatic prostate cancer is the major cause of mortalities from this disease. African-American (AA) men have the highest incidence and mortality rate compared to any other race such as Caucasian American (CA). Despite recent advances, the cellular and molecular mechanisms that contribute to this disparity are unknown, obstructing the development of an effective therapy for this disease. Genetic and epigenetic studies have indicated that the biology of prostate cancer in AA men is substantially different from CA. Here, we investigate the dopamine (DA) signaling to better understand the mechanism of prostate cancer disparity. Our analysis of the prostate cancer public data sets showed that the dopamine receptor (DR) genes were amplified in up to 18% prostate cancer clinical cases. We have demonstrated that the levels of DR transcripts were significantly higher in the metastatic prostate cancer cell lines with African genetic ancestry than CA counters. We also demonstrate that the efficacy of pimozide, a potent DRD inhibitor and an FDA-approved antipsychotic, on AA cells was significantly higher than CA cells. In addition, we have found that L-dopa, an immediate precursor of DA differentially regulates the growth of AA and CA prostate cancer cells in a dose dependent manner. We also found that carbidopa, a potent inhibitor of the dopa decarboxylase, suppressed prostate cancer cell growth by L-dopa and showed that carbidopa re-sensitized CRPC cell line to enzalutamide, a potent inhibitor of androgen receptor (AR) signaling. These observations suggest that DA/DR signaling plays a critical role in prostate cancer disparity, making the DA/DR-AR axis a viable therapeutic target to reduce disparities in cancer mortality. Citation Format: Isaiah R. Pickett, Ava M. Boston, Marwah M. Almathkour, Camille Ragin, Mehmet A. Bilen, Adeboye O. Osunkoya, Bekir Cinar. The role of dopamine signaling in prostate cancer disparities [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1022.