Background and Aim: Breast cancer as the most commonly diagnosed cancer is the second cause of cancer death among women. Since this problem has been increased all over the world, discovery and development of new treatments with high efficacy and low side effects is critical. Probiotics due to production of anti-cancer compounds can affect important metabolic pathways, and regulate proliferation, differentiation, apoptosis and angiogenesis. The purpose of this study was to investigate the effects of local probiotics from Iran on proliferation of MDA-231and MCF-7 breast cancer cell lines. Methods: Local probiotic bacteria mix including Lactobacillus acidophilus, Bifidobacterium bifidum and Lactobacillus casei were cultured on MRS broth at 37°C for 24 h, centrifuged at 4500 rpm for 10 min and supernatant lyophilized for further experiments. MCF-7 and MDA-231 (3× 103 per well) were seeded on 96-well culture plates in DMEM containing 10% (v/v) FCS ml) of local probiotics from Iran for 72 h. Cell viability was determined by MTT [3-(4,5- dimethylthiazol-2-y-2,5- iphenyltetrazolium bromide] assay. Results: Based on the MTT assay the bacteria mix inhibited growth of MDA-231 cells in a time and dose-dependent manner and the ( Moreover, the mix had no considerable effect on MCF7 cells growth. Conclusion: According to the results, the probiotic bacteria mix might play an important role on growth inhibition of MDA-231 cells.
