EFFECTS OF SOYBEAN ISOFLAVONES ON CELL-GROWTH AND APOPTOSIS OF THE HUMAN PROSTATIC-CANCER CELL-LINE LNCAP

Background: Epidemiological studies have suggested that soybean isofla vones are associated with a lower risk of prostate cancer. However, th e mechanisms of prostate cancer prevention by soybean isoflavones have yet to be fully clarified. Methods: Two soybean isoflavones (genistei n and daidzein) and their glucosides (genistin and daidzin) were teste d for their effects on cell growth and apoptosis of the LNCaP human pr ostatic cancer cell line. Results: Among these isoflavones, genistein was found to inhibit the growth of LNCaP most effectively, with an IC5 0 value of 40 mu M. The inhibition of cell growth by genistein was acc ompanied by the suppression of DNA synthesis and the induction of apop tosis. Expression of prostate-specific antigen (PSA) in LNCaP was also significantly reduced by the treatment with genistein. Conclusions: T he results suggest that genistein might primarily influence human pros tate cancer development by reducing tumor growth.