title: Implications of altered glutathione metabolism in aspirin-induced oxidative stress and mitochondrial dysfunction in HepG2 cells.
abstract: We have previously reported that acetylsalicylic acid (aspirin, ASA) induces cell cycle arrest, oxidative stress and mitochondrial dysfunction in HepG2 cells. In the present study, we have further elucidated that altered glutathione (GSH)-redox metabolism in HepG2 cells play a critical role in ASA-induced cytotoxicity. Using selected doses and time point for ASA toxicity, we have demonstrated that when GSH synthesis is inhibited in HepG2 cells by buthionine sulfoximine (BSO), prior to ASA treatment, cytotoxicity of the drug is augmented. On the other hand, when GSH-depleted cells were treated with N-acetyl cysteine (NAC), cytotoxicity/apoptosis caused by ASA was attenuated with a significant recovery in oxidative stress, GSH homeostasis, DNA fragmentation and some of the mitochondrial functions. NAC treatment, however, had no significant effects on the drug-induced inhibition of mitochondrial aconitase activity and ATP synthesis in GSH-depleted cells. Our results have confirmed that aspirin increases apoptosis by increased reactive oxygen species production, loss of mitochondrial membrane potential and inhibition of mitochondrial respiratory functions. These effects were further amplified when GSH-depleted cells were treated with ASA. We have also shown that some of the effects of aspirin might be associated with reduced GSH homeostasis, as treatment of cells with NAC attenuated the effects of BSO and aspirin. Our results strongly suggest that GSH dependent redox homeostasis in HepG2 cells is critical in preserving mitochondrial functions and preventing oxidative stress associated complications caused by aspirin treatment.
authors.affiliation: Department of Biochemistry, Faculty of Medicine and Health Sciences, United Arab Emirates (UAE) University, Al Ain, United Arab Emirates. h.raza@uaeu.ac.ae
authors.forename: Haider
authors.initials: H
authors.lastname: Raza
authors.forename: Annie
authors.initials: A
authors.lastname: John
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D000154:Aconitate Hydratase / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001241:Aspirin / Q000494:pharmacology*; D015415:Biomarkers / Q000378:metabolism; D019328:Buthionine Sulfoximine / Q000494:pharmacology; D053148:Caspase 3 / Q000378:metabolism; D019069:Cell Respiration / Q000187:drug effects; D053938:DNA Fragmentation / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D005978:Glutathione / Q000378:metabolism*; D005982:Glutathione Transferase / Q000378:metabolism; D056945:Hep G2 Cells; D006801:Humans; D015227:Lipid Peroxidation / Q000187:drug effects; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D015415:Biomarkers; D017382:Reactive Oxygen Species; D019328:Buthionine Sulfoximine; D000255:Adenosine Triphosphate; D005982:Glutathione Transferase; D053148:Caspase 3; D000154:Aconitate Hydratase; C041116:leukotriene-C4 synthase; D005978:Glutathione; D001241:Aspirin; D000111:Acetylcysteine