Aberrant Activation of a Gastrointestinal Transcriptional Circuit in Prostate Cancer Mediates Castration Resistance

Prostate cancer exhibits a lineage-specific dependence on androgen signaling. Castration resistance involves reactivation of androgen signaling or activation of alternative lineage programs to bypass androgen requirement. We describe an aberrant gastrointestinal-lineage transcriptome expressed in ∼5% of primary prostate cancer that is characterized by abbreviated response to androgen-deprivation therapy and in ∼30% of castration-resistant prostate cancer. This program is governed by a transcriptional circuit consisting of HNF4G and HNF1A. Cistrome and chromatin analyses revealed that HNF4G is a pioneer factor that generates and maintains enhancer landscape at gastrointestinal-lineage genes, independent of androgen-receptor signaling. In HNF4G/HNF1A-double-negative prostate cancer, exogenous expression of HNF4G at physiologic levels recapitulates the gastrointestinal transcriptome, chromatin landscape, and leads to relative castration resistance. •A GI-lineage transcriptome is prevalent in castration-resistant prostate cancer•HNF4G and HNF1A regulate each other and the GI-lineage transcriptome•HNF4G is a pioneer factor that generates and maintains enhancers at GI-lineage genes•Exogenous HNF4G expression in prostate cancer leads to castration resistance Shukla et al. identify an aberrantly expressed gastrointestinal-lineage transcriptome governed by HNF4G and HNF1A in ∼30% of castration-resistant prostate cancer. HNF4G is a pioneer factor for this transcriptional program and its ectopic expression at physiologic levels reduces sensitivity to hormone deprivation.