569 Investigating the Role of FOXA2 During the Transition to Neuroendocrine Prostate Cancer

OBJECTIVES/GOALS: The goal of this project is to characterize the efficacy of FOXA2 as a potential biomarker for patients with metastatic castrate-resistant prostate adenocarcinoma (CRPC) before transitioning to neuroendocrine prostate cancer (NEPC). NEPC currently has no therapeutic options and poor mechanistic understand of its origins. METHODS/STUDY POPULATION: In our study, we have utilized a multi-omics approach to characterize the potential efficacy of FOXA2 as a prognostic biomarker in numerous patient-derived castrate-resistant prostate cancer (CRPC) models. We have performed ATAC-, ChIP-, RNA-seq and proteomics to fully characterize where FOXA2 is binding genome-wide, how FOXA2 alters chromatin accessibility dynamics, identify regulatory gene targets of FOXA2, and identify FOXA2 protein-protein interactors. We have supported these findings using publicly available data from independent CRPC and NEPC patient cohorts and prostate cancer cell models. RESULTS/ANTICIPATED RESULTS: Our findings show that FOXA2 overexpression suppressed androgen signaling and promoted progression to a NEPC phenotype under short- and long-term androgen deprivation conditions, respectively. Further, FOXA2 redirected the chromatin accessibility landscape to be consistent with an NEPC gene expression program, including increased chromatin accessibility for key NEPC transcription factors. FOXA2 ChIP-seq showed FOXA2 to be bound at known NEPC driver genes and epigenetic modifiers across multiple stages of prostate cancer progression. Lastly, we discovered that FOXA2 physically interacts with key NEPC TFs and epigenetic regulators, suggesting that these FOXA2 physical interactions are required for NEPC progression. DISCUSSION/SIGNIFICANCE: This project will determine the efficacy of FOXA2 as a biomarker in advanced prostatecancer samples, which will translate as a potentially useful tool for clinicians to use for treatment of advanced prostate cancer patients.