SETD7 functions as a transcription repressor in prostate cancer via methylating FOXA1 [ChIP-seq]

We recently reported that in prostate cancer LSD1 can demethylate the lysine 270 of FOXA1 to stabilize FOXA1 chromatin binding and thus can enhance the activities of AR and other transcription factors that require FOXA1 as a pioneer factor. However, the methyltransferase that can methylate FOXA1 and negatively regulate the LSD1-FOXA1 oncogenic axis remains unknown. SETD7 is initially identified as a transcriptional activator through methylating histone 3 lysine 4 but can also function as a methyltransferase on other non-histone substrates. However, its function in PCa remains poorly understood. In this study, we found that SETD7 confers tumor suppressor activity in PCa cells and that loss of SETD7 expression is significantly associated with PCa progression and tumor aggressiveness. Mechanistically, we found that SETD7 primarily acts as a transcriptional repressor in CRPC cells by functioning as a methyltransferase of FOXA1-K270 to disrupt FOXA1-mediated transcription. Overall, our study provides novel mechanistic insights into the tumor-suppressive and transcriptional repression activities of SETD7 in mediating PCa progression and therapy resistance. ChIP-seq analysis of SETD7 in 22Rv1 cells. ChIP-seq analyses of FOXA1 in 22Rv1 cells stably expressing shNTC or shSETD7. ChIP-seq analysis of FOXA1 in LNCaP cells treated with with vehicle and GSK2879552 together with or without PFI-2.