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Differential effects of whole soy extract and soy isoflavones on apoptosis in prostate cancer cells
Author(s) -
Hsu Anna,
Ho Emily,
Bray Tammy
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a993
Subject(s) - genistein , lncap , isoflavones , daidzein , apoptosis , prostate cancer , soy isoflavones , soy protein , chemistry , annexin , phytoestrogens , endocrinology , cancer research , cancer cell , medicine , cancer , food science , biochemistry , biology , estrogen
Previous studies have suggested that soy isoflavones, especially genistein and diadzein, have chemoprotective effects in prostate cancer, however, the precise mechanism are unclear. Soy contains a mixture of soy isoflavones and other bioactive components, thus a whole food approach may be more effective than using individual soy isoflavones for chemoprevention. This study sought to compare the effects of whole soy extracts with genistein and diadzein on prostate cancer cell proliferation, apoptosis and changes in NFκB activation. Androgen‐dependent LnCap and androgen‐independent PC3 prostate cancer cells were treated with soy extract, genistein or diadzein for 48h and analyzed for cell cycle alterations, Annexin V staining and multicaspase activity. The soy extract induced an increase in the subG 1 peaks, Annexin V and multicaspase staining at concentrations as low as 25μM in PC3 and LnCap cells, whereas genistein and diadzein did not induce apoptosis until concentrations >100μM. Furthermore, addition of 25μM soy extract induced a higher percentage of apoptotic cells than equal concentrations of genistein or diadzein (p<0.001). Preliminary data did not show suppression of NFκB activation with treatments. Soy extracts also had no effect on apoptosis in the benign prostate cells, suggesting that the effects of soy are cancer‐cell specific. These results suggest that a whole food approach using foods that bear a combination of active compounds may be more efficacious for chemoprevention compared to individual compounds. In vivo studies exploring the effect of soy and individual soy isoflavones on hormone‐induced prostate cancer Noble rat model is underway. This work was supported by CA107693.