title: The role of microcystin-LR in the induction of apoptosis and oxidative stress in CaCo2 cells.
abstract: The increasing presence of toxic cyanobacteria in drinking and recreational water bodies, and their potential to impact on human and animal health is cause for concern. Recent work suggests that apoptosis plays a major role in the toxic effects induced by microcystin-LR (MCLR) in the gastrointestinal tract; however, the biochemical pathway remains elusive. Exposure of CaCo2, a human colon carcinoma cell line, and MCF-7, a cell line deficient in pro-caspase-3, cells to 50 microM MCLR induced similar reductions in cell viability as measured by MTT and LDH leakage. The role of MCLR induced oxidative stress in the initiation of apoptosis was investigated over a 2-hr period, and it was found that there was an increase in the release of H(2)O(2) in the first 30 min of exposure for both cell lines. Both cell lines exhibited a dose-dependent increase in both micro- and millicalpain after 24 h exposure to MCLR suggesting a role for protease activation in MCLR-induced apoptosis in non-hepatic human derived cell lines.
authors.affiliation: Department of Biochemistry and Microbiology, University of Port Elizabeth, P.O. Box 1600, Port Elizabeth 6000, South Africa.
authors.forename: Nicolette
authors.initials: N
authors.lastname: Botha
authors.forename: Michelle M
authors.initials: MM
authors.lastname: Gehringer
authors.forename: Tim G
authors.initials: TG
authors.lastname: Downing
authors.forename: Maryna
authors.initials: M
authors.lastname: van de Venter
authors.forename: Enid G
authors.initials: EG
authors.lastname: Shephard
mesh_terms: D017209:Apoptosis; D001427:Bacterial Toxins / Q000633:toxicity; D001943:Breast Neoplasms / Q000201:enzymology*; D018938:Caco-2 Cells / Q000187:drug effects / Q000201:enzymology*; D002277:Carcinoma / Q000201:enzymology*; D020169:Caspases / Q000187:drug effects / Q000378:metabolism*; D000458:Cyanobacteria; D004791:Enzyme Inhibitors / Q000633:toxicity; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D008387:Marine Toxins; D052998:Microcystins; D018384:Oxidative Stress / Q000187:drug effects; D010456:Peptides, Cyclic / Q000633:toxicity*; D017382:Reactive Oxygen Species / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D001427:Bacterial Toxins; D004791:Enzyme Inhibitors; D008387:Marine Toxins; D052998:Microcystins; D010456:Peptides, Cyclic; D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide; D020169:Caspases; C057862:cyanoginosin LR