AR and Familial prostate cancer: In a 10-day cell growth assay, GSK650394 showed no effect on LNCaP cell growth in the absence of androgens but exhibited strong inhibition of the androgen-stimulated growth of LNCaP cells with an IC50 value of approximately 1 μM, indicating that GSK650394 selectively inhibits androgen receptor (AR)-driven prostate cancer cells, but not AR-liberated prostate cancer cells.