Carbonyl cyanide p-(trifluoromethoxy) phenylhydrazone (FCCP) as an O2− generator induces apoptosis via the depletion of intracellular GSH contents in Calu-6 cells

SummaryCarbonyl cyanide p-(trifluoromethoxy) phenylhydrazone (FCCP) is an uncoupler of mitochondrial oxidative phosphorylation in eukaryotic cells. Here, we investigated an involvement of O2− and GSH in FCCP-induced Calu-6 cell death and examined whether ROS scavengers rescue cells from FCCP-induced cell death. Levels of intracellular O2− were markedly increased depending on the concentrations (5–100 μM) of FCCP. A depletion of intracellular GSH content was also observed after exposing cells to FCCP. Stable SOD mimetics, Tempol and Tiron did not change the levels of intracellular O2−, apoptosis and the loss of mitochondrial membrane potential (ΔΨm). Treatment with thiol antioxidants, NAC and DTT, showed the recovery of GSH depletion and the reduction of O2− levels in FCCP-treated cells, which were accompanied by the inhibition of apoptosis. In contrast, BSO, a well-known inhibitor of GSH synthesis, aggravated GSH depletion, oxidative stress of O2− and cell death in FCCP-treated cells. Taken together, our data suggested that FCCP as an O2− generator, induces apoptosis via the depletion of intracellular GSH contents in Calu-6 cells.