2.7. Reporter gene assay

LNCaP cells were plated in 24‐well plates and incubated for 24 h. Cells were cotransfected with PSA(6.1 kb)‐luciferase reporter or V7BS₃‐luciferase reporter and AR‐V7 expression vector or pGL4.28 empty vector under serum‐free and phenol red‐free conditions. After 24 h, cells were pretreated for 1 h with vehicle, ENZ, EPI‐7170, or a combination before addition of 1 nm R1881 and then incubated for another 24 h. Cells were harvested, and relative luminescence units (RLU) in cell lysates were detected using Promega GloMax‐Multi Detection Luminometer (Promega, Madison, WI, USA). Protein concentrations of the cell lysates were determined by the Bradford method using Bio‐Rad Protein Assay Kit (Mississauga, ON, Canada). Luciferase activities were normalized to protein concentration.