Androgen receptor (AR)-mediated transcription is the primary driver of prostate cancer growth and proliferation [1, 2]. Androgen treatment induces AR binding to the DNA primarily at regulatory enhancer elements, resulting in rapid changes to transcriptional profiles [3-6]. However, the precise relationship between androgen-induced gene expression changes and AR-enhancer binding has not been characterized in the context of 3D chromatin interactions and therefore a high-resolution view of the temporal dynamics of androgen-induced gene activation is still missing.
To determine the molecular order of events associated with transcription of androgen-induced genes, we combined chromatin conformation capture (Hi-C and Promoter Capture Hi-C) with the profiling of transcription factor binding, histone modifications (CUT&RUN) and transcription (RNA-seq and TT-seq) during a finely resolved time-course of DHT treatment in prostate cancer cells (control, 5min, 10min, 20min, 30min, 2hrs, 4hrs and 16hrs). We found that chromatin remodelling, AR and FOXA1 binding at interacting promoters were transiently present at the earliest time-points, while androgen-induced gene activation and AR binding at distal regulatory elements occurred mostly at later time-points. Our results demonstrate that dynamic changes in AR-driven enhancer-promoter interactions precede gene activation and unexpectedly high levels of gene transcription were associated with loss of these interactions.
Our findings are consistent with the conclusion that enhancer-promoter interactions transiently activate gene expression, thereby uncoupling the temporal dynamics of chromatin interactions from those of transcription. This novel dataset provides a temporally resolved map of androgen-induced chromatin and transcription changes in prostate cancer, revealing potential causal relationships between 3D chromatin structure, AR binding at enhancers, and gene activation.