Effects of CDK8/19 Mediator Kinase inhibition on gene expression in castration-resistant prostate cancer cell line 22Rv1 and its derivatives grown in vitro.

RNA-Seq analysis was carried out to investigate the effects of selective CDK8/19 inhibitor SNX631 on gene expression in different 22RV1 derivatives grown in cell culture, under androgen-supplemented and androgen-deprived conditions. The 22Rv1 derivatives were generated as following: Parental 22Rv1 (Rv1-WT) were transduced with a lentivirus expressing luciferase, yielding the derivative Rv1-Luc. 22Rv1 cells with a double knockout of CDK8 and CDK19 (Rv1-dKO) were made via CRISPR/Cas9. Rv1-dKO cells were further transduced with lentiviruses to generate Rv1-dKO re-expression derivatives that express wild-type CDK8 or CDK19 (Rv1-dKO-CDK8 or Rv1-dKO-CDK19) and kinase-inactive D173A mutants (Rv1-dKO-CDK8M or Rv1-dKO-CDK19M). The effects of CDK8/19 inhibition on gene expression in 22Rv1 derivatives were evaluated as follows: (1) For effects under androgen-supplemented conditions, cells were seeded in FBS media, incubated overnight, and then treated with 0.1% DMSO (vehicle control) or 500 nM SNX631 in FBS media for 3 days. (2) For effects under androgen-deprived conditions, cells were first sub-cultured in CSS media for one passage (3-4 days) and then seeded in CSS media, incubated overnight, and then treated with 0.1% DMSO (vehicle control) or 500 nM SNX631 in CSS media for 3 days. Each treatment condition was done in biological triplicate.