Influences of miR-206 on Sensitivity of Estrogen Receptor-α Positive Breast Cancer Cells MCF-7 to Tamoxifen

Objective To investigate the influences of miR-206 on estrogen receptor-α expression and the sensitivity of breast cancer cells MCF-7 to tamoxifen. Methods The levels of miR-206 and ERα mRNA of breast cancer cells MCF-7 were quantitated by RT-PCR; the change of expression of miR-206 and ERα mRNA were quantitated after MCF-7 cells were transfected by miR-206 mimic, inhibitor and corresponding negative controls for 24h; cell growth was measured by MTT after transfected MCF-7 cells were treated with 5ug/ml tamoxifen for 24h. Results Compared with corresponding negative controls, miR-206 mimic decreased ERα mRNA expression while increased miR-206 expression in MCF-7 cells but had no notably effect on cell growth after tamoxifen treatment for 24h(t=-1.169, P=0.276 ); miR-206 inhibitor increased ERα mRNA expression while decreased miR-206 expression in MCF-7 cells and had notably effect on cell growth after tamoxifen treatment for 24h (t=-3.054, P=0.016). Conclusion Downregulating miR-206 expression could increase the sensitivity of ERα positive breast cancer cells MCF-7 to tamoxifen.