Gamma Tocopherol Reduced Chemotherapeutic-Induced ROS in an Ovarian Granulosa Cell Line, But Not in Breast Cancer Cell Lines In Vitro.

Doxorubicin and cyclophosphamide are used to treat breast cancer, but they also cause infertility through off-target cytotoxicity towards proliferating granulosa cells that surround eggs. Each chemotherapeutic generates reactive oxygen species (ROS) but the effects of the combination, or the antioxidants alpha (alpha Toc) and gamma tocopherol (gamma Toc) on ROS in breast cancer or ovarian cells are unknown. Human breast cancer (MCF7, T47D) and ovarian cancer (OVCAR, COV434) cells were loaded with DCDFA and exposed (1, 2, 3, 24 h) to the MCF7-derived EC25 values of individual agents, or to combinations of these. ROS were quantified and viable cells enumerated using crystal violet or DAPI. Each chemotherapeutic killed similar to 25% of MCF7, T47D and OVCAR cells, but 57 +/- 2% (doxorubicin) and 66 +/- 2% (cyclophosphamide) of the COV434 granulosa cells. The combined chemotherapeutics decreased COV434 cell viability to 34 +/- 5% of control whereas doxorubicin + cyclophosphamide + gamma Toc reduced ROS within 3 h (p < 0.01) and reduced cytotoxicity to 54 +/- 4% (p < 0.05). alpha Toc was not cytotoxic, whereas gamma Toc killed similar to 25% of the breast cancer but none of the ovarian cells. Adding gamma Toc to the combined chemotherapeutics did not change ROS or cytotoxicity in MCF7, T47D or OVCAR cells. The protection gamma Toc afforded COV434 granulosa cells against chemotherapy-induced ROS and cytotoxicity suggests potential for fertility preservation.