Wogonin from Scutellaria baicalensis-Induced Radioresistance in MCF-7 Breast Cancer Cell Line

nu-Objectives: Breast cancer shows the highest incidence and cancer-related deaths among women worldwide. Radiotherapy is used for treating different stages of breast cancer. Several polyphenols have increased the effectiveness of radiotherapy. Wogonin is a flavone compound abundant in the root of Chinese skullcap. This compound induced apoptosis and inhibited proliferation distinctively in cancer cells. We studied effect of wogonin on the response of a typical breast cancer cell line to ionizing radiation. Methods: MCF-7 cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Cell counting and double staining apoptosis assays were also used to find suitable physiologically relevant concentrations of wogonin. Cells treated with wogonin were exposed to different doses of X-ray and clonogenic survival assay was utilized to determine the effect of wogonin on survival from radiation. Results: Wogonin treatment decreased the viability of MCF-7 cells in a dose- and time-dependent manner. It decreased number of cells and increased percent of apoptotic cells dose dependently. Cells pretreated with 5 and 10 µM concentrations of wogonin 3 days before radiation showed increased radioresistance compared with cells that were not treated with wogonin. Conclusion: Treatment of MCF-7 breast cancer cells with wogonin made them more resistant to ionizing radiation.