Abstract 2364: MicroRNA-1205 directly targets ONECUT2 in neuroendocrine prostate cancer cells

Abstract

Abstract One of six deaths globally is due to cancer. In 2018, prostate cancer (PCa) represented 1.28 million cases worldwide, the second most frequent cancer diagnosis and fifth leading cause of death in men. Currently, the mortality rate of PCa has experienced a steady increase due to the progression of metastatic castration-resistant prostate cancer (mCRPC). As an androgen driven disease, androgen deprivation therapies (ADTs) have been employed for treatment. However, despite ADTs, mCRPC develops by maintaining AR signaling, which can eventually lead to progression of AR-independent neuroendocrine PCa (NEPC). NEPC is observable in 1 in 5 men with mCRPC and associated with poor outcome. Therefore, further understanding the mechanisms of progression to mCRPC and NEPC is required. The 8q24 human chromosomal region associated with Increased PCa incidence and aggressiveness contains the PVT1 (Plasmocytoma Variant Translocation 1) locus. The PVT1 locus encodes six microRNAs, including microRNA-1205 (miR-1205) in PCa. Our laboratory previously confirmed that miR-1205 is underexpressed in PCa tissue in comparison to normal prostatic tissue and in CRPC cells in comparison to non-CRPC cells. To understand the molecular mechanism of miR-1205, we performed RNA pull down and RNA sequencing analysis to identify miR-1205 molecular targets in non-tumorigenic RWPE-1 prostate epithelial cells and PCa cells (MDA PCa 2b (metastatic PCa), PC-3 (NEPC), and C4-2B (CRPC)). We identified one cut homeobox 2 (ONECUT2 or OC2) as a direct molecular target of miR-1205. ONECUT2 is a master regulator of transcriptional factors that drives NEPC by through regulating hypoxia signaling or inducing neuroendocrine markers. ONECUT2 enrichment was approximately 3-fold higher in RWPE-1 (P=0.26), 2-fold in PC-3 (P=0.06), 1-fold in C4-2B (P=0.05) and MDA PCa 2b (P=0.02) cells. The significant binding of miR-1205 to ONECUT-2 in the PC-3 NEPC cell line suggests that miR-1205 regulation of ONECUT2 may be an important molecular mechanism in NEPC. Consequently, further study of miR-1205 and ONECUT2 in NEPC is required. Citation Format: Bachelard Dieujuste, Michelle Naidoo, Olorunseun Ogunwobi. MicroRNA-1205 directly targets ONECUT2 in neuroendocrine prostate cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2364.