Ethanolic Extract of Propolis from Kerman Area Triggers Apoptosis and Arrests Cell Cycle in Three Human Breast Cancer Cell Lines MDA-MB-231, SKBR and MCF-7

Background: Cancer is one of the major health problems worldwide and natural resources are being explored to develop anticancer drugs with fewer side effects. Iranian propolis contains components including flavonoids and polyphenols and has various medicinal properties. The aim of this study was to investigate the effect of Ethanolic Extract of Sirch Propolis (EESP) on three breast cancer cell lines. Methods: The MDA-MB-231, SKBR-3 and MCF-7 cells were treated for 24 and 48 h at the presence of 1% and 10% fetal bovine serum (FBS) concentration. MTT, BrdU and flow cytometry assays were used for measuring cytotoxicity, cell proliferation and apoptosis. Results: The highest cytotoxicity was seen on MDA-MB-231 cell at the presence of 1% and 10% FBS respectively following 48 h treatment. BrdU assay showed that treatment with 200 μg/ mL of EESP at the presence of 1% FBS for 48 h, reduced proliferation of MDA-MB-231 cell to 75% and that of MCF-7 and SKBR-3 cells to 70% and 60% respectively. Cell cycle analysis by flow cytometry showed that EESP at 200 μg/mL for 48h, induced G0/G1 phase arrest in MCF-7 and SKBR-3 cells and G2/M, S phase arrest in MDA-MB-231 cell. The cytotoxic effects of EESP were primarily found to be due to the induction of early stage apoptosis on SKBR-3 cell and early and late stage apoptosis on MCF-7 and MDA-MB-231 cells. Conclusion:The results demonstrated that EESP is a natural anticancer mixture capable of reducing breast cancer cells proliferation and inducing cell cycle arrest and apoptosis in them.