title: Isoniazid-induced apoptosis in HepG2 cells: generation of oxidative stress and Bcl-2 down-regulation.
abstract: Isoniazid (INH) is a first-line antibiotic used in the treatment of infections caused by Mycobacterium tuberculosis. However it has a serious limitation of being hepatotoxic. Delineating the mechanism underlying INH-induced hepatotoxicity may be beneficial in devising ways to counteract its toxic manifestations. Studies in human hepatoma HepG2 cells have indicated that INH exposure causes induction of apoptosis. This study was aimed at identifying the key components/pathways of the INH-induced apoptotic pathway using HepG2 cells. HepG2 cells were exposed to increasing concentrations of INH (6.5, 13, 26, and 52 mM). Hydrogen peroxide (0.3 mM) served as positive control. After incubating for specific time intervals cells were harvested and evidences of cytotoxicity, oxidative stress, and apoptosis were sought. The findings indicated that INH exposure causes increased ROS generation along with alteration in levels of enzymatic antioxidants such as Superoxide dismutase, Catalase, and Glucose-6-Phosphate dehydrogenase. Altered Bcl-2/Bax content, cytochrome-c translocation, caspase activation, and DNA fragmentation emphasized involvement of apoptosis.
authors.affiliation: Division of Toxicology, Central Drug Research Institute, Lucknow 262 001, (CSIR) India. smraticdri@gmail.com
authors.forename: Smrati
authors.initials: S
authors.lastname: Bhadauria
authors.forename: Rajeev
authors.initials: R
authors.lastname: Mishra
authors.forename: Ranjana
authors.initials: R
authors.lastname: Kanchan
authors.forename: Chakrapani
authors.initials: C
authors.lastname: Tripathi
authors.forename: Anurag
authors.initials: A
authors.lastname: Srivastava
authors.forename: Ashutosh
authors.initials: A
authors.lastname: Tiwari
authors.forename: Sharad
authors.initials: S
authors.lastname: Sharma
mesh_terms: D000995:Antitubercular Agents / Q000633:toxicity*; D017209:Apoptosis; D053148:Caspase 3 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D045304:Cytochromes c / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D056945:Hep G2 Cells; D006801:Humans; D007538:Isoniazid / Q000633:toxicity*; D018384:Oxidative Stress; D021381:Protein Transport; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: D000995:Antitubercular Agents; D019253:Proto-Oncogene Proteins c-bcl-2; D017382:Reactive Oxygen Species; D051028:bcl-2-Associated X Protein; D045304:Cytochromes c; D005954:Glucosephosphate Dehydrogenase; D002374:Catalase; D013482:Superoxide Dismutase; D053148:Caspase 3; D053453:Caspase 9; D007538:Isoniazid