There has been a controversy in the oncology field about the use of antioxidants along with chemotherapeutics in cancer treatment. This study aimed to investigate the effects of a potent antioxidant (astaxanthin) co-treatment with a promising anti-cancer drug (carbendazim), which is in phase I clinical trials, on MCF-7 breast cancer cell proliferation. MCF-7 cells were treated with carbendazim, astaxanthin, or their combinations and incubated for 24 h. After the incubation, each treatment group was evaluated for proliferation, cell cycle progression, and production of reactive oxygen species (ROS) using WST-1, flow cytometry, and CM-H2DCFDA, respectively. All tested carbendazim and astaxanthin combinations increased the anti-proliferative effect of Carb treatment alone and increased the G2/M phase cell cycle arrest compared to the DMSO-treated control. Astaxanthin, at all concentrations tested, reduced the elevated intracellular ROS levels induced by the carbendazim treatment. Our data suggest that astaxanthin and carbendazim co-treatment enhances the anti-proliferative effect of carbendazim as a single agent, while alleviating the carbendazim treatment-associated ROS production in MCF-7 cells. These findings may contribute to the current debate on the use of antioxidants along with anti-cancer drugs in cancer chemotherapy.
Keywords: Astaxanthin; Breast cancer; Carbendazim; MCF-7.