Isoflavone‐induced gene expression changes in lymphocytes from postmenopausal women

Abstract

Soy isoflavones may have various beneficial effects, including decreased cancer risk in women and men, amelioration of hot flashes and a decrease in bone resorption in postmenopausal women. It has been suggested that the metabolite equol formed from the soy isoflavone daidzein, is the active component, and that equol producers have a better response to diets containing isoflavones. In addition, there has been concern that isoflavone-mediated activation of estrogen receptors could enhance breast cancer proliferation in postmenopausal women. Using microarray analysis, we investigated changes in peripheral lymphocyte gene expression induced by oral treatment with high-doses of purified soy isoflavones for 84 days. The samples were stratified based on the equol-producer status of the subjects. From 30 postmenopausal women that successfully completed this Phase I clinical trial, 26 arrays were available for analysis; 16 from the treated group (11 equol producers and 5 non-equol producers), and 10 from the placebo group. We report that isoflavones change gene expression profiles in both equol and non–equol producers, and these changes were related to, among others, cell differentiations, cAMP metabolism and genes that are estrogen responsive. This work was funded by a grant from National Cancer Institute (NCI-N01-CN-75035).