Dietary phytoestrogen regulates estrogen receptor gene expression in human mammary carcinoma cells
1999
Hsu, J.T. | Hsu, W.L. | Ying, C.
The level of estrogen receptor mRNA and cell proliferation were examined in the estrogen responsive human breast carcinoma cell lines MCF-7 and T-47D upon the addition of biochanin A, a dietary phytoestrogen present in plant foods. Results show that T-47D cell growth was stimulated by biochanin A at low concentrations (<1.76x10(-5)M), but inhibited at higher concentration (>3.52x10(-5)M). The elevated T-47D cell growth due to biochanin A treatment was effectively blocked by the addition of a pure antiestrogen ICI 182,780. A close association between cell proliferation and estrogen receptor mRNA was noted in MCF-7 and T-47D cells in response to biochanin A. The estrogen receptor mRNA increased at levels at cell growth stimulatory concentrations of biochanin A and decreased at growth inhibitory concentrations. Simultaneous addition of antiestrogen abolished the increase of estrogen receptor mRNA in response to biochanin A in T-47D cells. Our results indicate that the effects of biochanin A on cell proliferation may be mediated through estrogen receptor in estrogen responsive human breast carcinoma cells. In addition, they demonstrate that plant secondary metabolites such as the dietary phytoestrogens exist in nature that may contribute to the total estrogen exposure of the human population.
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