title: Structures of oxaliplatin-oligonucleotide adducts from DNA.
abstract: Oxaliplatin, [(1R,2R)-cyclohexane-1,2-diamine](ethanedioato-O,O')platinum(II) shows a great efficiency against colorectal cancer. Although the mode of action of oxaliplatin is not yet understood, it is commonly accepted that binding of oxaliplatin to DNA prevents DNA synthesis and alters protein to DNA binding. In order to elucidate the modified DNA-protein interaction and thus to understand the mechanisms leading to cellular misinterpretation of DNA information and apoptosis, we have identified the preferential binding sites and the dynamics of the oxaliplatin-DNA intrastrand and interstrand adducts at the oligomer level using high-performance liquid chromatography/electrospray ionization-tandem mass spectrometry (HPLC/ESI-MS/MS) and HPLC/inductively coupled plasma-MS for quantitative studies. We used a combination of benzonase, alkaline phosphatase and Nuclease S1 for digestion. This digestion procedure allows the study of platinated oligomeric nucleotides and more complex interstrand adducts. The digestion products were mostly chromatographically separated and characterized using HPLC/ESI-ion trap MS/MS experiments. We could show that the adducts to guanine and adenine are quite dynamic; that is, the ratios are changing for several days. In addition, the resulting adducts provide evidence for the action of the digesting enzymes and indicate that the adduct spectrum at the oligomeric level is different to that at the commonly studies dinucleotide level.
authors.affiliation: Humboldt-Universitaet zu Berlin, Department of Chemistry, Berlin, Germany.
authors.forename: Shereen
authors.initials: S
authors.lastname: Mowaka
authors.forename: Matthias
authors.initials: M
authors.lastname: Ziehe
authors.forename: Dalia
authors.initials: D
authors.lastname: Mohamed
authors.forename: Ulrike
authors.initials: U
authors.lastname: Hochkirch
authors.forename: Jürgen
authors.initials: J
authors.lastname: Thomale
authors.forename: Michael W
authors.initials: MW
authors.lastname: Linscheid
mesh_terms: D000818:Animals; D001483:Base Sequence; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D004247:DNA / Q000737:chemistry; D018736:DNA Adducts / Q000737:chemistry*; D008099:Liver / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D008969:Molecular Sequence Data; D009841:Oligonucleotides / Q000737:chemistry*; D009944:Organoplatinum Compounds / Q000737:chemistry*; D000077150:Oxaliplatin; D051381:Rats; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D018736:DNA Adducts; D009841:Oligonucleotides; D009944:Organoplatinum Compounds; D000077150:Oxaliplatin; D004247:DNA; C427203:calf thymus DNA