Molecular Biology Basis for the Response of Poly (ADP-Ribose) Polymerase and NAD Metabolism to DNA Damage Caused by Mustard Alkylating Agents

摘要

The mechanism of toxicity of sulfur mustard was investigated by examining the biochemical effects of the analog 2-chioroethylethyl sulfide (CEES) in both human Jurkat cells as well as normal human lymphocytes. Exposure of both cells to CEES resulted in a marked decrease in the intracellular concentration of the reduced form of glutathione (3511), and CEES-induced cell death was potentiated by L-buthionine sulfoximine, an inhibitor of GSH synthesis. CEES increased the endogenous production of reactive oxygen species (ROS) in Jurkat cells, and CEES-induced cell death was potentiated by hydrogen peroxide. CEES induced various hallmarks of apoptosis, including collapse of the mitochondrial membrane potential, proteolytic processing and activation of procaspase-3, and cleavage of poly (ADP-ribose) polymerase. The effects of CEES on the accumulation of ROS, the intracellular concentration of GSH, the mitochondrial membrane potential, and caspase-3 activity were all inhibited by pretreatment of cells with the GSH precursor N-acetyl cysteine or with 3511- ethyl ester. Furthermore, CEES-induced cell death was also prevented by these antioxidants CEES toxicity appears to be mediated, at least in part, by the generation of ROS and consequent depletion of GSH. Given that sulfur mustard is still a potential biohazard, the protective effects of antioxidants against CEES toxicity demonstrated in Jurkat cells and normal human lymphocytes may provide the basis for development of a therapeutic strategy to counteract exposure to this chemical weapon.