title: Characterization of oxaliplatin-DNA adduct formation in DNA and differentiation of cancer cell drug sensitivity at microdose concentrations.
abstract: (trans-R, R)-1,2-diaminocyclohexaneoxalatoplatinum(II) (oxaliplatin) is a recently approved platinum analogue for use in the chemotherapy of metastatic colorectal cancer. Like many cytotoxic drugs, oxaliplatin exerts its antitumor effects by covalent modification of DNA. We report an accelerator mass spectrometry (AMS) assay to measure the kinetics of oxaliplatin-induced DNA damage and repair. We determined the apparent rate of oxaliplatin adduction to salmon sperm DNA. The oxaliplatin-DNA adduct distribution was further investigated at the nucleoside level by HPLC-AMS. Cultured platinum-sensitive testicular (833K) and platinum-resistant breast and bladder (MDA-MB-231 and T24, respectively) cancer cells were incubated with a subpharmacological concentration of oxaliplatin (0.2 microM). Both cellular and DNA radiocarbon contents in the drug-sensitive testicular cells had approximately twice the area under the curve as compared to the more platinum-resistant cell lines, implying that differential accumulation of the drug may be responsible for the sensitivity of cancer cells to platinum treatment. The lowest concentration of radiocarbon measured was approximately 1+/-0.1 amol/microg of DNA, when assaying 1 microg of DNA. This sensitivity for measuring oxaliplatin-DNA adducts is the highest reported to date. The sensitivity offered by this method may be applicable to other DNA-damaging drugs, metabolisms studies, and diagnostics development.
authors.affiliation: Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, 7000 East Avenue, L-452, Livermore, California 94551, USA. hah2@llnl.gov
authors.forename: Sang Soo
authors.initials: SS
authors.lastname: Hah
authors.forename: Rhoda A
authors.initials: RA
authors.lastname: Sumbad
authors.forename: Ralph W
authors.initials: RW
authors.lastname: de Vere White
authors.forename: Kenneth W
authors.initials: KW
authors.lastname: Turteltaub
authors.forename: Paul T
authors.initials: PT
authors.lastname: Henderson
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects*; D045744:Cell Line, Tumor; D002851:Chromatography, High Pressure Liquid; D004247:DNA / Q000378:metabolism; D018736:DNA Adducts / Q000378:metabolism*; D004273:DNA, Neoplasm / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D015394:Molecular Structure; D009944:Organoplatinum Compounds / Q000494:pharmacology*; D000077150:Oxaliplatin; D012474:Salmon; D013094:Spermatozoa
chemical_list: D000970:Antineoplastic Agents; D018736:DNA Adducts; D004273:DNA, Neoplasm; D009944:Organoplatinum Compounds; D000077150:Oxaliplatin; D004247:DNA