title: hOGG1-Cys326 variant cells are hypersensitive to DNA repair inhibition by nitric oxide.
abstract: The repair of 8-oxo-7,8-dihydroguanine in the DNA of mammalian cells is initiated by 8-oxoguanine DNA glycosylase (OGG1). A frequent polymorphism in the human OGG1 gene, rs1052133, causes the substitution of serine by cysteine at amino acid 326 of the protein and has been associated with an altered risk for various types of cancer in some populations. The OGG1-Cys326 protein appears to have normal enzymatic activity, but greater sensitivity to oxidation than the serine variant. Here, we describe a comparison of the cellular repair by the two OGG1 variants under stress conditions characteristic of inflammation, namely in cells pretreated with nitric oxide (NO) or pre-exposed to hyperthermia. The results show that NO at concentrations causing negligible DNA damage and little cytotoxicity strongly reduces the repair rates of oxidized purines in the DNA of HeLa cells overexpressing the OGG1-Cys326 variant. The reduction in repair was much less pronounced in isogenic cells overexpressing the OGG1-Ser326 variant. Similar results were observed in EBV-transformed lymphocytes from donors homozygous for the two OGG1 variant alleles. In contrast, hyperthermia-induced stress caused a repair retardation that was independent of the OGG1 polymorphism. The repair inhibition by NO in the variant cells gave rise to increased genetic instability, measured as increased micronuclei formation after oxidant exposure. The results could explain a higher risk of malignant transformation in inflamed tissues of carriers of this variant allele.
authors.affiliation: Institute of Pharmacy and Biochemistry, University of Mainz, Staudingerweg 5, 55099 Mainz, Germany, Institute of Molecular and Cellular Radiobiology, CEA, 18 route du Panorama, 92265 Fontenay-aux-Roses, France, Inserm, U967, 92265 Fontenay-aux-Roses, France, Université Paris Diderot, U967, 92265 Fontenay-aux-Roses, France, Université Paris Sud, U967, 92265 Fontenay-aux-Roses, France and Inserm U612, Institut Curie, Bats 110-112, Centre Universitaire, 91405 Orsay, France.
authors.forename: Eva
authors.initials: E
authors.lastname: Moritz
authors.affiliation: Institute of Pharmacy and Biochemistry, University of Mainz, Staudingerweg 5, 55099 Mainz, Germany, Institute of Molecular and Cellular Radiobiology, CEA, 18 route du Panorama, 92265 Fontenay-aux-Roses, France, Inserm, U967, 92265 Fontenay-aux-Roses, France, Université Paris Diderot, U967, 92265 Fontenay-aux-Roses, France, Université Paris Sud, U967, 92265 Fontenay-aux-Roses, France and Inserm U612, Institut Curie, Bats 110-112, Centre Universitaire, 91405 Orsay, France.
authors.forename: Karin
authors.initials: K
authors.lastname: Pauly
authors.affiliation: Institute of Molecular and Cellular Radiobiology, CEA, 18 route du Panorama, 92265 Fontenay-aux-Roses, France, Inserm, U967, 92265 Fontenay-aux-Roses, France, Université Paris Diderot, U967, 92265 Fontenay-aux-Roses, France, Université Paris Sud, U967, 92265 Fontenay-aux-Roses, France and.
authors.forename: Anne
authors.initials: A
authors.lastname: Bravard
authors.affiliation: Inserm U612, Institut Curie, Bats 110-112, Centre Universitaire, 91405 Orsay, France.
authors.forename: Janet
authors.initials: J
authors.lastname: Hall
authors.affiliation: Institute of Molecular and Cellular Radiobiology, CEA, 18 route du Panorama, 92265 Fontenay-aux-Roses, France, Inserm, U967, 92265 Fontenay-aux-Roses, France, Université Paris Diderot, U967, 92265 Fontenay-aux-Roses, France, Université Paris Sud, U967, 92265 Fontenay-aux-Roses, France and.
authors.forename: J Pablo
authors.initials: JP
authors.lastname: Radicella
authors.affiliation: Institute of Pharmacy and Biochemistry, University of Mainz, Staudingerweg 5, 55099 Mainz, Germany, Institute of Molecular and Cellular Radiobiology, CEA, 18 route du Panorama, 92265 Fontenay-aux-Roses, France, Inserm, U967, 92265 Fontenay-aux-Roses, France, Université Paris Diderot, U967, 92265 Fontenay-aux-Roses, France, Université Paris Sud, U967, 92265 Fontenay-aux-Roses, France and Inserm U612, Institut Curie, Bats 110-112, Centre Universitaire, 91405 Orsay, France epe@uni-mainz.de.
authors.forename: Bernd
authors.initials: B
authors.lastname: Epe
mesh_terms: D002460:Cell Line; D004249:DNA Damage / Q000187:drug effects; D045647:DNA Glycosylases / Q000235:genetics* / Q000378:metabolism; D004260:DNA Repair / Q000187:drug effects; D014644:Genetic Variation; D042822:Genomic Instability; D006801:Humans; D006979:Hyperthermia, Induced; D009569:Nitric Oxide / Q000378:metabolism* / Q000494:pharmacology; D018384:Oxidative Stress / Q000235:genetics; D011110:Polymorphism, Genetic; D055550:Protein Stability; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D009569:Nitric Oxide; D045647:DNA Glycosylases; C479058:oxoguanine glycosylase 1, human