Effectiveness of Graphene Oxide (GO) in Activating the Mitochondrial Pathway of Oxidative Stress-Induced Apoptosis in Breast Cancer Cells

Due to its unique physicochemical properties, graphene oxide (GO) is used in nanomedicine. Many studies have examined the effects of GO on cancer cells. However, there are no data on the mechanisms of action of GO in breast cancer. The aim of this study was to analyze the cytotoxic effect and mechanisms of action of GO on MDA-MB-231 and ZR-75-1 cell lines. Our findings show that GO induced cytotoxicity in MDA-MB-231 but not in ZR-75-1 cells. The cytotoxic effect of GO on fibroblasts was negligible. Cytotoxicity was associated with ROS synthesis, decreased mitochondrial membrane potential, and apoptosis/necrosis in MDA-MB-231 cells. In addition, we observed cell cycle arrest and increased P21 protein expression in MDA-MB-231 cells. Furthermore, we observed increased levels of proapoptotic proteins, decreased levels of antiapoptotic proteins, and activation of caspase-9 and caspase-3/7 in MDA-MB-231 cells. This study elucidates the possible mechanisms of action of GO in breast cancer cells.