title: Biological reactive intermediates that mediate dacarbazine cytotoxicity.
abstract: OBJECTIVE
  In the following, the cellular and molecular mechanism of cytotoxicity induced by prodrug dacarbazine toward the isolated rat hepatocytes was studied.
  
  
  METHODS
  Accelerated cytotoxicity screening technique (ACMS) was used to perform this study.
  
  
  RESULTS
  Addition of dacarbazine to isolated rat hepatocytes resulted in reactive oxygen species (ROS) formation, and lysosomal membrane leakiness before hepatocyte lysis occurred. Hepatocyte ROS generation was inhibited by desferoxamine (a ferric chelator). Cytotoxicity was prevented by antioxidants or ROS scavengers (mannitol or dimethylsulfoxide), cytochorome P450 inhibitors (phenylimidazole, diphenyliodonium chloride, 4-methylpyrazole, and benzylimidazole). In addition to lysosomal damage, dacarbazine caused hepatocyte protease activation and cell proteolysis.
  
  
  CONCLUSIONS
  Dacarbazine cytotoxicity is associated with ROS (H(2)O(2), O(2)(*-) ) generation. It is suggested that H(2)O(2) could cross the lysosomal membrane, react with lysosomal Fe(2+) to form hydroxyl radical (Haber-Weiss reaction) which is the major cause of lysosomal membrane leakiness, proteases, and other digestive enzymes' release and finally the cell death.
authors.affiliation: Faculty of Pharmacy, Shaheed Beheshti University of Medical Sciences, Tehran, PO Box 14155-6153, Iran. j.pourahmadjaktaji@utoronto.ca
authors.forename: Jalal
authors.initials: J
authors.lastname: Pourahmad
authors.forename: Marzieh
authors.initials: M
authors.lastname: Amirmostofian
authors.forename: Farzad
authors.initials: F
authors.lastname: Kobarfard
authors.forename: Jafar
authors.initials: J
authors.lastname: Shahraki
mesh_terms: D000818:Animals; D018906:Antineoplastic Agents, Alkylating / Q000633:toxicity*; D016923:Cell Death / Q000187:drug effects; D003606:Dacarbazine / Q000633:toxicity*; D022781:Hepatocytes / Q000187:drug effects* / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D017665:Hydroxyl Radical / Q000378:metabolism; D066298:In Vitro Techniques; D007425:Intracellular Membranes / Q000378:metabolism; D007501:Iron / Q000378:metabolism; D008247:Lysosomes / Q000378:metabolism; D008297:Male; D010447:Peptide Hydrolases / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism*
chemical_list: D018906:Antineoplastic Agents, Alkylating; D017382:Reactive Oxygen Species; D017665:Hydroxyl Radical; D003606:Dacarbazine; D006861:Hydrogen Peroxide; D007501:Iron; D010447:Peptide Hydrolases