title: A tubule cell model for ifosfamide nephrotoxicity.
abstract: Mechanisms leading to ifosfamide (IF)-induced renal damage have not been fully elucidated. Recent work suggests that localized renal tubular metabolism of IF and the production of the nephrotoxic chloroacetaldehyde may lead to nephrotoxicity. Presently no pharmacological method to reduce IF nephrotoxicity has been identified. The objectives of this study were to establish a tubule cell model for IF nephrotoxicity, to verify whether renal proximal tubular cells have the necessary cytochrome P450 (CYP) enzymes to oxidize IF, and whether they can metabolize IF to chloroacetaldehyde. CYP3A, and 2B mRNA and protein were identified in LLCPK-1 cells. The cells metabolized the R- and S-IF enantiomers to their respective 2- and 3-dechloroethylifosfamide metabolites, by-products of chloroacetaldehyde formation. Metabolite production was both time and concentration-dependent. IF did not affect cell viability. In contrast, glutathione-depleted cells showed time and dose-dependent damage. The presence of the relevant CYP enzymes in renal tubular cells along with their ability to metabolize IF to its 2- and 3-dechloroethylifosfamide metabolites suggests that nephrotoxic damage may result from the localized production of chloroacetaldehyde. Glutathione is a major defence mechanism against IF toxicity, thus pharmacological methods for replenishing intracellular glutathione may be effective in modulating IF-induced nephrotoxicity.
authors.affiliation: Division of Clinical Pharmacology and Toxicology, Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: Katarina
authors.initials: K
authors.lastname: Aleksa
authors.forename: Naomi
authors.initials: N
authors.lastname: Halachmi
authors.forename: Shinya
authors.initials: S
authors.lastname: Ito
authors.forename: Gideon
authors.initials: G
authors.lastname: Koren
mesh_terms: D000818:Animals; D018906:Antineoplastic Agents, Alkylating / Q000009:adverse effects* / Q000737:chemistry / Q000493:pharmacokinetics; D001189:Aryl Hydrocarbon Hydroxylases / Q000096:biosynthesis; D001711:Biotransformation; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D065702:Cytochrome P-450 CYP2B6; D051544:Cytochrome P-450 CYP3A; D008401:Gas Chromatography-Mass Spectrometry; D005978:Glutathione / Q000378:metabolism; D007069:Ifosfamide / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000737:chemistry / Q000493:pharmacokinetics; D007150:Immunohistochemistry; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D008954:Models, Biological; D010089:Oxidoreductases, N-Demethylating / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013237:Stereoisomerism; D013552:Swine
chemical_list: D018906:Antineoplastic Agents, Alkylating; D001189:Aryl Hydrocarbon Hydroxylases; D065702:Cytochrome P-450 CYP2B6; D051544:Cytochrome P-450 CYP3A; D010089:Oxidoreductases, N-Demethylating; D005978:Glutathione; C038007:dechloroethylifosfamide; D007069:Ifosfamide