Abstract

Androgen receptor (AR) signaling is a primary oncogenic driver of castration-resistant prostate cancer (CRPC), yet the mechanism remains incompletely understood. Through proteomic profiling of CRPC and primary PCa cells, we identify G Protein Nucleolar 3 (GNL3) as a novel AR coregulator. GNL3 physically interacts with AR, enhances its chromatin occupancy, and directly coactivates transcriptional programs that promote cell proliferation, including NEK2 and CDC20. Concurrently, GNL3 functions as a corepressor of immune-responsive genes such as CXCL10 and TAP1 via class I histone deacetylases (HDACs), thereby facilitating CD8+ T cell elimination and establishing an immunosuppressive tumor microenvironment. GNL3 expression and AR-GNL3 complex formation progressively increase from normal prostate to CRPC and correlate with poor clinical outcomes. Functionally, GNL3 knockdown sensitizes CRPC cells to AR antagonists and impairs tumor growth and metastasis. Furthermore, we demonstrate that combinatorial inhibition of NEK2, class I HDACs, and AR signaling can be a potential therapeutic strategy for CRPC. Overall, these findings establish GNL3 as a dual-function AR coregulator and therapeutic target, providing mechanistic insights into transcriptional regulation and immune evasion in advanced PCa.