Castration-resistant prostate cancer (CRPC) poses a major clinical challenge with the androgen receptor (AR) remaining to be a critical oncogenic player. Several lines of evidence indicate that AR induces a distinct transcriptional program after androgen deprivation in CRPCs.
However, the mechanism triggering AR binding to a distinct set of genomic loci in CRPC and how it promotes CRPC development remain unclear. We demonstrate here that atypical ubiquitination of AR mediated by an E3 ubiquitin ligase TRAF4 plays an important role in this process. TRAF4 is highly expressed in CRPCs and promotes CRPC development. It mediates K27-linked ubiquitination at the C-terminal tail of AR and increases its association with the pioneer factor FOXA1. Consequently, AR binds to a distinct set of genomic loci enriched with FOXA1- and HOXB13-binding motifs to drive different transcriptional programs including an olfactory transduction pathway. Through the surprising upregulation of olfactory receptor gene transcription, TRAF4 increases intracellular cAMP levels and boosts E2F transcription factor activity to promote cell proliferation under androgen deprivation conditions. Altogether, these findings reveal a posttranslational mechanism driving AR-regulated transcriptional reprogramming to provide survival advantages for prostate cancer cells under castration conditions.
Proceedings of the National Academy of Sciences of the United States of America. 2023 May 08 [Epub]
Ramesh Singh, Huan Meng, Tao Shen, Lance Edward V Lumahan, Steven Nguyen, Hong Shen, Subhamoy Dasgupta, Li Qin, Dileep Karri, Bokai Zhu, Feng Yang, Cristian Coarfa, Bert W O'Malley, Ping Yi
Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030., Department of Biology and Biochemistry, Center for Nuclear Receptors and Cell Signaling, University of Houston, Houston, TX 77204.