Overexpression of CuZnSOD or MnSOD protects satellite cells from doxorubicin‐induced apoptosis

Abstract

PURPOSE: Doxorubicin belongs to a family of anticancer drugs that exert cytotoxic effects by release of reactive oxygen species (ROS) and triggering apoptosis. Since antioxidant enzymes scavenge ROS and defend against apoptosis, we sought to determine whether overexpression of catalase, copper‐zinc superoxide dismutase (CuZnSOD), or manganese SOD (MnSOD) is protective against doxorubicin‐mediated cell death.METHODS: Primary satellite cell cultures were derived from the hindlimb muscles of wild type (WT) or transgenic mice overexpressing catalase, CuZnSOD, or MnSOD. Myoblasts were cultured in growth medium (10% FBS) until 80% confluency, then replated at equal density. Following a 24 hr treatment with or without 5μM doxorubicin, cells were fixed for DAPI and TUNEL staining.RESULTS: Doxorubicin induced a 60% decrease in nuclear number of WT cells, and this effect was abrogated in cells overexpressing CuZnSOD or MnSOD. The %TUNEL positive nuclei was elevated six‐fold in doxorubicin‐treated WT cells and only the CuZnSOD overexpressing cells were protected against this effect.CONCLUSIONS: Catalase overexpression did not protect cultured satellite cells from the cytotoxic effects of doxorubicin. However, overexpression of the cytosolic antioxidant enzyme, CuZnSOD, protects against DNA fragmentation, and overexpression of CuZnSOD or the mitochondrial enzyme, MnSOD, enhances cellular survival when challenged by a dose of doxorubicin known to induce apoptosis.Funded by the American Heart Association.