Cellular uptake of soy-derived phytoestrogens in vitro and in human whole blood

Epidemiological studies comparing typical Western and traditional Eastern lifestyles indicate that dietary intake of soyderived phytoestrogens, including genistein, daidzein, and equol, may have significant health protective effects on hormone-dependent cancers, osteoporosis and cardiovascular diseases. Phytoestrogens have been demonstrated to exert varying effects depending on tissue, endogenous hormone concentrations, and receptor types. Thus, a detailed understanding of the biodistribution and bioavailability of specific phytoestrogens is required in order to predict the subsequent biologic activities. In this study we aimed to investigate the cellular uptake of these soy-derived phytoestrogens in different cell types, including the mammary MCF-7/6 and MDAB-MB 231 cell lines, the ovarian Ishikawa Var-I cell lines and in murine adipocyte clusters. Furthermore, the biodistribution between serum and cell fraction was also investigated in human whole blood. Equol generally shows a higher cellular uptake when compared with genistein and daidzein. Therefore, equol may be more potent with respect to its relative bioactivity, which is corroborated by the observations of specific health effects associated with the equol-producer phenotype

8-Prenylnaringenin, the phytoestrogen in hops and beer, upregulates the function of the E-cadherin/catenin complex in human mammary carcinoma cells

The E-cadherin/catenin complex is a powerful invasion suppressor in epithelial cells. It is expressed in the human MCF-7 breast cancer cell line family, but functionally defective in the invasive MCF-7/6 variant. Previous experiments have shown that IGF-I, tamoxifen, retinoic acid and tangeretin are able to upregulate the function of this complex in MCF-7/6 cells. We investigated the effect of 8-prenylnaringenin (8-PN), the phytoestrogen present in hops and beer, on aggregation, growth and invasion in MCF-7/6 cells. 8-PN was found to stimulate E-cadherin-dependent aggregation and growth of MCF-7/6 cells in suspension. These effects could be inhibited by the pure antiestrogen ICI 182,780.8-PN did not affect invasion of MCF-7/6 cells in the chick heart assay in vitro. In all these aspects 8-PN mimics the effects of 17 beta -estradiol on MCF-7/6 cells