The objectives of this study were to determine the antiproliferation effect of
prostate cancer cell lines LNCaP and PC-3 as affected by 4
isoflavone fractions prepared from soybean cake and
isoflavone standards
genistein and
daidzein. With the MTT test, most treatments were effective in inhibiting
prostate cancer cell growth at a low dose of 5 and 10 mug/mL. In cell cycle analysis, the fractions of aglycon, a mixture of acetylglucoside and aglycon, as well as
genistein and a combination of
genistein and
daidzein standards exhibited a high G2/M ratio for LNCaP, as did the acetylglucoside,
genistein and a combination of
genistein and
daidzein standards for PC-3. Results of Western blotting revealed an increase in p53
protein expression of LNCaP following treatments of the aglycon fraction,
genistein and a combination of
genistein and
daidzein standards. However, all the treatments did not affect Bcl-2
protein expression significantly in both LNCaP and PC-3 cells. A decline in
cyclin B1 expression of LNCaP was observed for all the treatments, with the mixture of acetylglucoside and aglycon possessing the most pronounced effect. But for PC-3, a decrease in
cyclin B1 expression was shown for all the
isoflavones, with the exception of malonylglucoside,
glucoside and acetylglucoside fractions. The outcome of this study may provide a basis for possible production of functional food in the future with soybean cake as raw material.