title: Effect of soy-derived isoflavonoids on the induced growth of MCF-7 cells by estrogenic environmental chemicals.
abstract: Isoflavonoids are natural plant compounds and possess antitumorigenic properties. Many environmental chemicals have been found to be estrogenic and can enhance tumor growth in estrogen receptor-positive cells. In the present study, the effects of genistein, daidzein, biochanin A, formononetin, and equol on the proliferation of estrogen receptor-positive MCF-7 cells induced by synthetic chemicals 1-(o-chlorophenyl)-1-(p-chlorophenyl)-2,2,2-trichloroethane (o,p'-DDT), 4-nonylphenol (4-NP), and 5-octylphenol (5-OP) found in the environment were investigated. Genistein, biochanin A, equol, and to some extent daidzein, but not formononetin, at < 10 microM can enhance the growth of MCF-7 cells in the absence of environmental chemicals. Formononetin was toxic to MCF-7 cells at the tested concentrations. The environmental chemicals 4-NP, 5-OP, and o,p'-DDT and the natural estrogen 17 beta-estradiol at 5, 5, and 10 microM and 5 nM, respectively, induced proliferation of MCF-7 cells. In the presence of isoflavonoids (> 25 microM), the environmental chemical-induced cell proliferation was inhibited. Individually, genistein (IC50 = 25-33 microM) was the most potent inhibitor against the induced proliferation of MCF-7 cells of the isoflavonoids needed for a 50% suppression of growth induced by 4-NP, 5-OP, and o,p'-DDT. A mixture of isoflavonoids was the most potent inhibitor against the induced proliferation. Estrogen receptor-dependent and -independent pathways could be involved in the inhibitory actions of isoflavonids. Because it is impossible to have a chemical-free environment, the in vitro data presented here are of practical importance to develop evolving dietary strategies and tactics against the adverse health effects of environmental chemicals.
authors.affiliation: Department of Family Medicine and Community Health, Tufts University School of Medicine, Boston, MA 02111, USA.
authors.forename: S P
authors.initials: SP
authors.lastname: Verma
authors.forename: B R
authors.initials: BR
authors.lastname: Goldin
mesh_terms: D000473:Alkanes / Q000009:adverse effects; D016588:Anticarcinogenic Agents / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000209:etiology* / Q000378:metabolism; D003634:DDT / Q000009:adverse effects; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007529:Isoflavones / Q000627:therapeutic use*; D010575:Pesticides / Q000009:adverse effects*; D019800:Phenol / Q000009:adverse effects; D010636:Phenols / Q000009:adverse effects; D011960:Receptors, Estrogen / Q000378:metabolism*; D014407:Tumor Cells, Cultured / Q000378:metabolism
chemical_list: C113977:5-octylphenol; D000473:Alkanes; D016588:Anticarcinogenic Agents; D007529:Isoflavones; D010575:Pesticides; D010636:Phenols; D011960:Receptors, Estrogen; D019800:Phenol; D003634:DDT; C041594:4-nonylphenol