Modulation by hydroxytyrosol of oxidative stress and antitumor activities of paclitaxel in breast cancer.

PURPOSE: The main objective of this study was to test the therapeutic potential of hydroxytyrosol and its combination with paclitaxel in breast cancer on oxidative stress status. METHODS: Impact on proliferation rates of different chemotherapy administration patterns was assayed in MCF-7 and MDA-MB-231 breast cancer cell lines. Breast tumor-bearing rats were randomly assigned to Control, Hydroxytyrosol, Paclitaxel and Paclitaxel plus hydroxytyrosol groups, for 6 weeks. Tumor volume, cell proliferation and several systemic oxidative stress parameters were measured. Anti-proliferative activity in vitro experiments was correlated with in vivo experiments. RESULTS: Combination group did significantly reduce tumor volume when compared with paclitaxel alone. Additionally, the combination improved the antioxidant status without compromising the antitumor activity of standard chemotherapy. CONCLUSION: These findings reveal for the first time that hydroxytyrosol is an active partner in combined therapies with paclitaxel against breast cancer. Combination with hydroxytyrosol would also ensure a less oxidative impact of chemotherapeutic drugs that could potentially improve patient wellness.