Effect of the AR regulators on AR-dependent transcriptional activity and cell proliferation in human prostate cancer cells. (A) LNCaP cells stably expressing an AR-responsive probasin-luciferase reporter gene were transfected with siRNAs against the indicated factors or a scrambled, nonsilencing siRNA (control), and after 48 h, were treated with 10 nM R1881 for 24 h. Luciferase activity was measured, normalized to protein, and presented as relative luminescence units (RLUs). (B) The efficiency of knockdown of each factor was determined at the mRNA level relative to RPL19 and shown as relative mRNA expression. (White bars) Nonsilencing siRNA; (black bars) the indicated siRNAs. (C) LNCaP-abl cells were transfected with siRNAs against the indicated factor or a scrambled siRNA for the control cells, and cell proliferation was measured after 7 d. Data are represented as relative fluorescence units (RFUs). (D) The extent of knockdown was determined and represented as in B, and relative mRNA expression is shown. The experiment was performed in triplicate with error bars representing the standard deviation.