pS2 expression induced by American ginseng in MCF-7 breast cancer cells

Background: Alternative medicines are frequently used by patients with breast cancer for general health benefits. American ginseng, an herbal remedy, purportedly alleviates treatment-induced postmenopausal symptoms. Methods: Estrogenic potential of American ginseng root extract to induce the expression of pS2, an estrogen-regulated gene, was evaluated in breast cancer cell lines MCF-7, T-47D, and BT-20 by Northern and Western blot analysis. Competitive studies were performed with ginseng in combination with tamoxifen. Cell proliferation assays were performed using the tetrazolium dye procedure and direct cell count. Results: Ginseng and estradiol induce the expression of pS2 RNA and protein in MCF-7 cells, whereas tamoxifen suppresses expression. Neither ginseng nor estradiol induced increased pS2 expression in T-47D or BT-20 cell lines. Although estradiol exhibited a proliferative effect and tamoxifen had an inhibitory effect, ginseng demonstrated no significant effect on cell proliferation. Conclusions: The results of this study suggest that ginseng may exhibit estrogenlike effects on estrogen receptor-positive breast cancer cells by inducing pS2 expression and that the effect of ginseng may be mediated in part through the estrogen receptor. Because ginseng does not exhibit a proliferative effect, it may play a protective role against breast cancer rather than serve as a mitogen.