Combination of metformin and curcumin targets breast cancer in mice by angiogenesis inhibition, immune system modulation and induction of p53 independent apoptosis

Background: The effects of metformin (MET) and curcumin (CUR) single treatments have been tested against breast cancer; however, their combination has not been explored. Here, we evaluated the antitumor activity of MET and CUR combination against breast cancer in mice. Materials and methods: The antiproliferative activity of single and combined treatments against breast cancer cell lines was determined. Vascular endothelial growth factor (VEGF) and Trp53 expression was examined in EMT6/P cells. In vivo studies were carried out by inoculating BALB/c mice with EMT6/P cells and examining tumor growth and apoptosis induction in tumor sections. Furthermore, serum levels of different cytokines and transaminases and creatinine were measured to detect the immune response and toxicity, respectively. Results: The combination treatment exhibited the highest effects against tumor proliferation and growth. It significantly reduced VEGF expression, induced Trp53 independent apoptosis, triggered Th2 immune response and showed no toxicity. Conclusion: The combination can be a potential therapeutic option to treat breast cancer. However, further testing is needed to measure the exact serum levels of MET and CUR and to further explain the obtained results.