LNCaP, PC-3, DU145, 22Rv1, and HEK-293T cells were obtained from the American Type Culture Collection, and cultured as described (33 (link)). All the cell lines were authenticated on April 1, 2015, by the method of short tandem repeat profiling at the Genetica DNA Laboratories. Enzalutamide was purchased from Selleck Chemicals (Houston, TX). The following antibodies were used in Western blot analyses: anti-glyceraldehyde-3-phosphate dehydrogenase (GAPDH, Millipore), anti-AR (N-20, Santa Cruz), anti-AR-V7 (Precision Antibody), and anti-FLAG (M2, Sigma).