title: Characterization of covalent adducts of nucleosides and DNA formed by reaction with levuglandin.
abstract: Enhanced expression of cyclooxygenase-2 (COX-2) is associated with development of several cancers. The product of COX-2, prostaglandin H(2) (PGH(2)), can undergo spontaneous rearrangement and nonenzymatic ring cleavage to form the highly reactive levuglandin E(2) (LGE(2)) or D(2) (LGD(2)). Incubation with LGE(2) causes DNA-protein cross-linking in cultured cells, suggesting that levuglandins can directly react with DNA. We report the identification by liquid chromatography-tandem mass spectrometry of a stable levuglandin-deoxycytidine (LG-dC) adduct that forms upon reaction of levuglandin with DNA. We found that LGE(2) reacted with deoxycytidine, deoxyadenosine, or deoxyguanosine in vitro to form covalent adducts with a dihydroxypyrrolidine structure, as deduced from selective ion fragmentation. For LG-deoxycytidine adducts, the initial dihydroxypyrrolidine structure converted to a pyrrole structure over time. Reaction of LG with DNA yielded a stable LG-dC adduct with a pyrrole structure. These results describe the first structure of levuglandinyl-DNA adducts and provide the tools with which to evaluate the potential for LG-DNA adduct formation in vivo.
authors.affiliation: Department of Medicine, Vanderbilt University, Nashville,Tennessee 37232, USA.
authors.forename: Erica J
authors.initials: EJ
authors.lastname: Carrier
authors.forename: Venkataraman
authors.initials: V
authors.lastname: Amarnath
authors.forename: John A
authors.initials: JA
authors.lastname: Oates
authors.forename: Olivier
authors.initials: O
authors.lastname: Boutaud
mesh_terms: D002853:Chromatography, Liquid; D004247:DNA / Q000737:chemistry*; D009705:Nucleosides / Q000737:chemistry*; D011458:Prostaglandins E / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D009705:Nucleosides; D011458:Prostaglandins E; D004247:DNA; C047684:levuglandin E2