GCP (Genistein Combined Polysaccharide), a fermented product of soybean isoflavone extracts, is known to possess anti-tumor activity. Present study examined the effect of GCP and estrogen or the combination of GCP and estrogen on cell signal protein expressions in mammalian cancer MCF-7 cells and ovariectomized female rats. In TPA treated MCF-7 cells, p53 expression was higher in GCP and low estrogen treatments, whereas at high concentrations of estrogen, p53 expression was down regulated. By co-treating GCP and estrogen, this down-regulation was reversed by GCP, indicating that GCP could have an estrogen-antagonistic action. However, p21 expression down-regulation by high concentrations of estrogen could not be reversed by co-treatment with GCP. Eight-week old Sprague-Dawley female rats were ovariectomized and sham operated, and then maintained on a conventional diet for 3 weeks. These rats were fed seven dietary regiments (control-sham, control-ovx, estrogen-ovx, high concentrations of GCP-sham, low concentrations of GCP-ovx, high concentrations of GCP-ovx and genistein-ovx). The expressions of pp53 showed similar patterns between estrogen and low GCP fed animals, and high GCP fed rats revealed higher expression. COX-2, pERK1/2 and pJNKof low concentrations of GCP and estrogen fed rats had the similar expression patterns.

Keywords: Genistein combined polysaccharide, Ovariectomized rats, Estrogen treatment, MCF-7 cells, Cell signal protein expressions