Interaction of Dietary Genistein, Equol, and Aromatase Inhibitors on Growth of Estrogen-Dependent Human Breast Cancer (MCF-7Ca) Cell in Athymic Mice

Abstract

Abstract : We conducted a range-finding experiment to determine the appropriate dosage of androstenedione and Letrozole that will be used in the silastic implants. Next we evaluated effect of dietary genistein on the growth of estrogen-dependent breast tumors using an intratumoral aromatase expressing postmenopausal breast cancer (MCF-7Ca) model. For the range-finding experiment, ovariectomized athymic mice were divided into five treatment groups (15 mice per group); negative control (MCF-7Ca); 5 mg androstenedione (AD); 1 mg letrozole (LET), AD + LET, and 2 mg LET, AD + LET. For the interaction of genistein with Letrozole, ovariectomized athymic mice were divided into seven treatment groups (15 mice per group); negative control (MCF-7Ca); 5 mg androstenedione (AD); 1 mg letrozole (LET), AD + LET, AD + LET +250 ppm GEN, AD + LET +500 ppm GEN; AD + LET + 1000 ppm GEN. We identified an appropriate dosage of Letrozole and found that dietary genistein will stimulate the growth of MCF-7Ca tumors in the presences of Letrozole. Therefore, caution is necessary for postmenopausal women with estrogen-dependent breast cancer consuming dietary genistein.