5β-Dihydrotestosterone and mutant androgen receptor vulnerability in prostate cancer

Cell proliferation, AR-responsive reporter activity, RT-qPCR, RNA sequencing with gene set enrichment analysis, immunoblotting, and senescence-associated β-galactosidase staining were used to characterize ligand responses. RESULTS At nanomolar concentrations, 5β-DHT and 3β-etiocholanediol (3β-ecdiol) induced AR target genes and promoted AR-dependent C4-2 and LNCaP growth, although less potently than T. RNA sequencing showed that both metabolites activated the T-regulated AR transcriptional program with smaller differentially expressed gene footprints.

At high concentrations, 5β-DHT, but not the weaker agonist 3β-ecdiol or progesterone-class steroids, suppressed C4-2 and LNCaP proliferation. High-dose 5β-DHT also activated AR and suppressed growth in PC-3 cells expressing AR-W742C or AR-H875Y, whereas AR-null PC-3 cells were unaffected. High-dose 5β-DHT enriched androgen-response and senescence programs, suppressed G2M, E2F, and MYC-associated pathways, increased p21, p27, and p57, reduced RB phosphorylation and SKP2, and induced senescence-associated β-galactosidase activity.