Objective: To evaluate the inhibitory effect of genistin combined with anastrozole on the growth and apoptosis of breast tumor tissue, and to study their anti-cancer mechanism by using the model of 7,12-dimethylbenz [alpha] anthracene (DMBA)-induced mammary tumors following ovariectomy in Sprague-Dawley (SD) rats.
Methods: The DMBA induced postmenopausal SD rats were randomly divided into the control group, the genistein group, the anastrozole group, and the genistein combined with anastrozole group. The growth of tumors was observed in each group. The proliferation index and apoptosis index of tumor cells were determined. Moreover, estradiol (E2) and 17beta-HSD1 mRNA levels were determined by ELISA and RT-PCR respectively.
Results: The tumor growth was inhibited in the genistein group and the anastrozole group. The inhibitory ratio was significantly higher in the genistein combined with anastrozole group (P < 0.05). Compared with the control group, levels of E2 and 17beta-HSD1 mRNA decreased more significantly in the genistein combined with anastrozole group (P < 0.05).
Conclusions: Genistein could suppress the growth of mammary tumors in postmenopausal rats. It showed synergistic effect when combined with anastrozole, which resulted in reduced levels of E2 and 17beta-HSD1 mRNA. It had inhibitory effect on the growth of breast tumors.