Genistein Decrease Breast Cancer Stem Cells In MCF-7Cells

Background and Objective: According to the latest statistcs in2013, each yearwomen around the world die from the number of breast cancer is greater than15%ofoverall cancer deaths. Breast cancer is became the most common malignancy of women.Breast cancer stem cells are one of the most important reasons for chemotherapyresistance, tumor recurrence and metastasis. Thereby breast cancer stem cells especiallythe signaling pathway of breast cancer stem cells as a target for treatment is much moreeffective than routine therapy, and it provides a new way to complete cure breast cancer.Asian and European countries have different diet structure. Genistein is the keythat cause the lower incidence of breast cancer in Asian residents, especially inSoutheast. Genistein is a naturally isflavones in soybean plants. It can effect throughWnt-βcatenin signaling pathway, Notch1, MAPK and ER signaling pathway. What’smore, these signaling pathways play an important role in the regulation of breast cancerstem cells at the same time. Nowadays, there is increasing number of researches payattention to the Hedgehog signaling pathway in breast cancer stem cells and evaluatethat down regulate the Hedgehog signaling pathway can inhibit breast cancer stem cells.In this study, we evaluated genistein, a natural compound derived from soybean,for its efficacy to inhibit breast cancer stem cells and its potential mechanism.Methods: CCk-8assay, colony formation assay and cell apoptosis analysis wereused to evaluate the effect of genistein on breast cancer cells. In vitro, we usedmammosphere formation assay, CD44+CD24-staining and western blotting to evaluate the effect of genistein on breast cancer stem cells. Then a nude mouse xenograft modelwas employed to determine whether genistein could target breast cancer stem cells invivo, as assessed by immunohistochemistry. The potential mechanism was investigatedutilizing western blotting and real-time PCR assay.Results:1. CCK-8assay suggest that geniatein can depress the proliferation of breast cancercells. And the higher concentrations were significantly enhance its inhibition. The IC50of24h is32.5g/ml. The colony formation assay showed that the survival fraction of5g/ml genistein is81%. And0,15and30g/ml genistein treated early apoptosis ratewere1.5%,18.38%and29.45%respectively in cell apoptosis analysis.2. Genistein reduced the size and number of mammosphere, and decreasedCD44+CD24-cell population from1.79%to0.88%~0.93%in human breast cancer cells.Western blot analysis showed that the expression of ALDH1protein in breast cancercells by using0,5and10g/ml Genistein respectively is1.57±0.21,1.02±0.37and0.71±0.43.3. After injection the nude mouse with genistein for21days, the0,5and10g/mlgenistein cause the weight of tumor is2.21±0.72,1.38±0.65and0.84±0.47respectively. Immunohistochemistry evaluate that the different concentration ofgenistein can decrease the ALDH1in the nude mouse xenograft model.4. Western blotting and real-time PCR analysis evaluate that genisteindown-regulated Hedgehog signaling pathway.Conclusion:1. Genistein inhibits proliferation and induces apoptosis of breast cancer cells.2. Genistein inhibits breast cancer stem cells both in vitro and vivo.3. Its potential mechanism maybe genistein can down-regulates Hedgehogsignaling pathway. These findings support the use of genistein for chemoprevention ofbreast cancer stem cells and warrant further clinical evaluation.