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

Daniela Figueroa Gonzalez,Fiona Young

doi:10.3390/antiox9010051

Abstract

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 (αToc) and gamma tocopherol (γToc) 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 ~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 + γToc reduced ROS within 3 h (p < 0.01) and reduced cytotoxicity to 54 ± 4% (p < 0.05). αToc was not cytotoxic, whereas γToc killed ~25% of the breast cancer but none of the ovarian cells. Adding γToc to the combined chemotherapeutics did not change ROS or cytotoxicity in MCF7, T47D or OVCAR cells. The protection γToc afforded COV434 granulosa cells against chemotherapy-induced ROS and cytotoxicity suggests potential for fertility preservation.

Highlights

IntroductionIntracellular reactive oxygen species (ROS) [1,2,3] are crucial for normal cell metabolism [3,4,5,6]and ROS generation is highly regulated by either enzymatic (catalases, peroxidases and dismutases) or non-enzymatic (vitamin A, C or E) reductive molecules
Intracellular reactive oxygen species (ROS) [1,2,3] are crucial for normal cell metabolism [3,4,5,6]and ROS generation is highly regulated by either enzymatic or non-enzymatic reductive molecules
T47D and MCF7 cells were derived from mammary epithelial cells

Summary

Introduction

Intracellular reactive oxygen species (ROS) [1,2,3] are crucial for normal cell metabolism [3,4,5,6]and ROS generation is highly regulated by either enzymatic (catalases, peroxidases and dismutases) or non-enzymatic (vitamin A, C or E) reductive molecules. Intracellular reactive oxygen species (ROS) [1,2,3] are crucial for normal cell metabolism [3,4,5,6]. Cells produce ROS after exposure to radiation or chemotherapeutics [7], many of which induce ROS to toxic levels as part of their mechanism of action [8]. The combination of doxorubicin (Dox) and cyclophosphamide is often used to treat breast cancer [9,10,11]. Dox is an anthracycline agent that causes apoptosis by intercalating into double-stranded. A second mechanism of action involving ROS has been described [5,13,14]

Objectives

Results

Conclusion