title: Potentiation of mitomycin C cytotoxicity by glutathione depletion in a multi-drug resistant mouse leukemia cell line.
abstract: This study was undertaken to elucidate the mechanism of cross-resistance to mitomycin C (MMC) in a multi-drug resistant mouse leukemia cell line (P388/R-84). The P388/R-84 cells were 6.2-fold more resistant to MMC as compared to the sensitive cells (P388/S). Since oxygen radical formation has been suggested to be important in MMC cytotoxicity, MMC-dependent peroxidation of membrane lipids (an index of oxygen radical formation) was compared in these cell lines. MMC-dependent lipid peroxidation was 2.56-fold higher using P388/S cell extract when compared to that of P388/R-84 cells. Depletion of cellular glutathione (GSH) levels in the resistant cells produced a 1.76-fold increase in MMC-dependent lipid peroxidation. MMC cytotoxicity was also increased significantly by GSH depletion in P388/R-84 cells. These results suggest that cellular resistance to MMC in P388/R-84 cells may, at least in part, be due to the reduced formation of oxyradicals in these cells.
authors.affiliation: Mercy Cancer Center, Mercy Hospital of Pittsburgh, PA 15219.
authors.forename: B H
authors.initials: BH
authors.lastname: Xu
authors.forename: S V
authors.initials: SV
authors.lastname: Singh
mesh_terms: D000818:Animals; D004351:Drug Resistance; D004354:Drug Screening Assays, Antitumor; D004357:Drug Synergism; D005978:Glutathione / Q000172:deficiency* / Q000378:metabolism; D007941:Leukemia P388 / Q000188:drug therapy* / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D051379:Mice; D016685:Mitomycin / Q000494:pharmacology* / Q000633:toxicity; D017382:Reactive Oxygen Species / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D017382:Reactive Oxygen Species; D016685:Mitomycin; D005978:Glutathione