Abstract 6282: Novel androgen related gene network in prostate cancer cell model

Abstract Prostate cancer stands as the foremost cause of cancer-related deaths among men in the United States, with the primary treatment being androgen receptor (AR) antagonists relying on current androgen signaling knowledge. Most of this knowledge is derived from next-generation sequencing experiments, but the oversight of splice variants and highly similar sequences in multiple loci can hinder a comprehensive understanding. In an effort to unveil the complete androgen receptor transcriptional program, we employed a novel sequencing analysis protocol. Using a R1881-LNCaP model, we identified 212 upregulated and 92 downregulated genes, of which a notable one-third (68 upregulated and 39 downregulated) had not been previously associated with androgen. Among these novel transcripts, 5.6% lacked splice variants, while 16.3% exhibited one or more splice variants, including 3.8% from seven unique gene families. Recognized androgen-regulated genes, such as ORM1, STEAP4, NPPC, ORM2, and KLK3, were validated as upregulated, while GRB10, FN1, PPFIA2, and PLA2G2A were confirmed as downregulated in this in-vitro model. Utilizing chromatin immunoprecipitation-sequencing (ChIP-seq) data, we found that 13% of the genes contained at least one androgen response element within 5 kb upstream or downstream. Further validation through real-time PCR confirmed the expression levels of 90% of the selected genes (18). Ingenuity Pathway Analysis revealed two major regulators (ESRRA and ARFGEF2) in causal networks likely interacting with the novel genes. Intriguingly, 57.1% of ESRRA-involved genes contained at least one ESRRA binding site in a ChIP-seq dataset. Although ESRRA is known to activate androgen biosynthesis in castration-resistant prostate cancer, its interaction with AR and co-regulation of androgen signaling remain unknown. Ongoing studies involve the characterization of these networks in prostate cancer cell lines, examining anchorage-independent capacity, invasion, migration, proliferation, and progression. Data collection and comparison will ascertain whether the signaling is driven by mutated AR, and the role of ARv7 will be elucidated through gene lockdown experiments. Citation Format: Alex L. McDonald, Spencer Snow, Shuk-mei Ho, Yuet-kin Leung. Novel androgen related gene network in prostate cancer cell model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6282.