Anastrozole and Binimetinib, a Synergism Against Breast Cancer Cells

Background and Objectives: Worldwide, breast cancer affects more than 2.3 million women each year, and its treatment has been a challenge in the field of oncology. Its tendency to develop drug resistance, as well as the heterogeneity of the disease, poses a clinical challenge for its eradication. In order to overcome these barriers, this project focused on evaluating the response of breast cancer cells to exposure to an aromatase inhibitor (anastrozole) and a MEK inhibitor (binimetinib) as a combination drug treatment, in terms of their viability and migration. Materials and Methods: The cyto-toxicity of the treatment was evaluated in the 3T3-L1 cell line; viability and migration were evaluated in the MCF-7 and MDA-MB-231 breast cancer cell lines; and a synergy analysis of the combination of drugs was performed. Results: Synergy in cytotoxicity was observed with the combination of drugs at concentrations of 50 μg/mL for anastrozole and 6 μg/mL for binimetinib in MCF-7 and at concentrations of 100 μg/mL for anastrozole and 2 μg/mL for binimetinib in MDA-MB-231. Cytotoxicity was observed in breast cancer cell lines but not in 3T3-L1 fibroblast cells at the selected doses. A significant decrease in cell migration was obtained in the MCF-7 cell line with the combination of drugs compared to the control. Conclusions: In vitro results suggest that both binimetinib and its combination with anastrozole are potential treatments for future studies against hormone receptor-positive breast cancer.