Transcriptome analysis of effects of AHR knockdown in Enzalutamide-resistant CWR-R1 and C4-2B cells

Enzalutamide (ENZ) is an inhibitor of the androgen receptor (AR) widely used in managing castration-resistant prostate cancer (CRPC). AHR was found upregulated in different Enzalutamide-resistant (ENZR) prostate cancer cell lines. Knocking down AHR significantly decreased the growth of CWR-R1ENZR and C4-2BENZR cells. To elucidate the underlying mechanism of AHR-mediated growth, we transcriptionally profiled CWR-R1ENZR and C4-2BENZR cells stably expressing control and two AHR-targeting shRNAs. AHR maintained androgen response in CWR-R1ENZR cells likely through driving the expression of many genes targeted by both the androgen receptor and glucocorticoid receptor. Interestingly, knockding down AHR did not have the same effect in C4-2BENZR cells. Instead of strengthing AR signaling, AHR maintained features of neuroendocrine differentiation, an AR-independent mechanism of ENZ resistance, in C4-2BENZR cells. Our results supported that AHR regulates transcriptional networks promoting ENZ resistance in a lineage-dependent manner and holds great potential as a therapeutic target. Overall design: Total RNA was isolated and treated with DNAseI from one control and two AHR knockdown CWR-R1ENZR and C4-2BENZR cell lines.