title: Development of a liquid chromatography-electrospray ionization tandem mass spectrometry method for detecting oxaliplatin-DNA intrastrand cross-links in biological samples.
abstract: Cellular resistance, both intrinsic and acquired, poses a problem in the effectiveness of platinum-based chemotherapy. The cytotoxic activity of Pt-based chemotherapeutic agents is derived from their ability to react with cellular DNA. Oxaliplatin binds to the N7 position of the purine DNA bases, forming mainly intrastrand cross-links between either two adjacent guanines (GG), an adjacent adenine and guanine (AG), or two guanines separated by an unmodified nucleotide (GNG). We report the development of a liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method for measuring GG and AG intrastrand cross-links formed by oxaliplatin. The limits of detection for GG-oxPt and AG-oxPt were 23 and 19 adducts per 10 (8) nucleotides, respectively. We compare the formation and persistence of intrastrand cross-links between wild-type and glutathione transferase P null mice (GSTP null) treated with oxaliplatin. No significant difference was observed in the level of intrastrand cross-links formed by oxaliplatin between the mouse strains in liver, kidney, and lung DNA. Adduct levels were greatest in liver and lowest in lung tissue.
authors.affiliation: Cancer Biomarkers and Prevention Group, Biocentre, University of Leicester, University Road, Leicester, U.K. rclp1@le.ac.uk
authors.forename: Rachel C
authors.initials: RC
authors.lastname: Le Pla
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Ritchie
authors.forename: Colin J
authors.initials: CJ
authors.lastname: Henderson
authors.forename: C Roland
authors.initials: CR
authors.lastname: Wolf
authors.forename: Chris F
authors.initials: CF
authors.lastname: Harrington
authors.forename: Peter B
authors.initials: PB
authors.lastname: Farmer
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D002853:Chromatography, Liquid / Q000379:methods*; D002945:Cisplatin / Q000378:metabolism / Q000494:pharmacology / Q000633:toxicity; D003432:Cross-Linking Reagents / Q000737:chemistry / Q000378:metabolism*; D004247:DNA / Q000032:analysis* / Q000378:metabolism; D018736:DNA Adducts / Q000032:analysis / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D009944:Organoplatinum Compounds / Q000378:metabolism / Q000494:pharmacology / Q000633:toxicity*; D000077150:Oxaliplatin; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014018:Tissue Distribution
chemical_list: D000970:Antineoplastic Agents; D003432:Cross-Linking Reagents; D018736:DNA Adducts; D009944:Organoplatinum Compounds; D000077150:Oxaliplatin; D004247:DNA; D002945:Cisplatin