Glutathione peroxidase and oxidative stress.

In this study, overexpression of the cDNA for the major cytoplasmic glutathione peroxidase isoenzyme, GSH Peroxidase 1 (GSHPx-1), in human MCF-7 breast cancer cells has been shown to significantly increase the tolerance of these cells to oxidative stress produced by hydrogen peroxide or by the redox cycling of the quinone-containing anticancer agent doxorubicin. These experiments suggest that intracellular detoxification of hydrogen peroxide by the glutathione-glutathione peroxidase cycle plays a critical role in resistance against oxidant stress produced by xenobiotics.