Enhancement of taxane-induced cytotoxicity and apoptosis by gossypol in human breast cancer cell line MCF-7

Purpose: Gossypol is a natural polyphenolic compound extracted from cotton plant (Gossypium species) which has shown potent inhibitory effect on cell growth of many types of cancers. In this study, we aimed to evaluate the interaction of gossypol with some conventional drugs known to be effective in the treatment of breast cancer like taxanes, doxorubicin, gemcitabine, cisplatin and vinorelbine, in MCF-7 breast cancer cells. Materials and methods: The XTT viability assay was used to evaluate the cytotoxicity of various cytotoxic agents alone and in combination with gossypol in MCF-7 breast cancer cells. The combination effect analysis of Chou and Talalay was used to identify the most synergistic drug combinations. The possible synergistic effects of the combination of drugs on apoptosis were also evaluated by using two different apoptosis assays. Results: We identified strong synergistic cytotoxic and apoplotic activity of gossypol with taxanes among all other studied cytotoxic drugs. Conclusion: This study provides proof that gossypol combined with taxanes may have potential as a novel future treatment for breast cancer.