title: Dioxododecenoic acid: a lipid hydroperoxide-derived bifunctional electrophile responsible for etheno DNA adduct formation.
abstract: It has been proposed that 13(S)-hydroperoxy-9Z,11E-octadecadienoic acid [13(S)-HPODE]-mediated formation of 4-oxo-2(E)-nonenal and 4-hydroxy-2(E)-nonenal arises from a Hock rearrangement. This suggested that a 4-oxo-2(E)-nonenal-related molecule, 9,12-dioxo-10(E)-dodecenoic acid (DODE), could also result from the intermediate formation of 9-hydroperoxy-12-oxo-10(E)-dodecenoic acid. A recent report has described the formation of DODE-derived etheno adducts when 13(S)-HPODE was allowed to decompose in the presence of 2'-deoxynucleosides or DNA. However, the regioselectivity of lipid hydroperoxide-derived DODE addition to 2'-deoxyguanosine (dGuo) or other 2'-deoxynucleosides was not determined. The structure of carboxynonanone-etheno-dGuo formed from vitamin C-mediated 13(S)-HPODE decomposition has now been established by a combination of 1H and 13C NMR spectroscopy studies of its bis-methylated derivative. The site of dGuo methylation was first established as being at N-5 rather than at O-9 from NMR analysis of a methyl derivative of the model compound, heptanone-etheno-dGuo. (1)H,(13)C 2D heteronuclear multiple bond correlations were then used to establish unequivocally that the bis-methyl derivative of carboxynonanone-etheno-dGuo was 3-(2'-deoxy-beta-d-erythropentafuranosyl)imidazo-7-(9' '-carboxymethylnona-2' '-one)-9-oxo-5-N-methyl[1,2-a]purine rather than its 6-(9' '-carboxymethylnona-2"-one)-9-oxo-5-N-methyl[1,2-a]purine regioisomer. Therefore, etheno adduct formation occurred by initial nucleophilic attack of the exocyclic N(2) amino group of dGuo at the C-12 aldehyde of DODE to form an unstable carbinolamine intermediate. This was followed by intramolecular Michael addition of the pyrimidine N1 of dGuo to C-11 of the resulting alpha,beta-unsaturated ketone. Subsequent dehydration gave 3-(2'-deoxy-beta-d-erythropentafuranosyl)imidazo-7-(9' '-carboxynona-2' '-one)-9-oxo-[1,2-a]purine (carboxynonanone-etheno-dGuo). An efficient synthesis of DODE was developed starting from readily available 1,8-octanediol using a furan homologation procedure. This synthetic method allowed multigram quantities of DODE to be readily prepared. Synthetic DODE when reacted with dGuo gave carboxynonanone-etheno-dGuo that was identical with that derived from vitamin C-mediated 13(S)-HPODE decomposition in the presence of dGuo.
authors.affiliation: Center for Cancer Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6160, USA.
authors.forename: Seon Hwa
authors.initials: SH
authors.lastname: Lee
authors.forename: Maria V
authors.initials: MV
authors.lastname: Silva Elipe
authors.forename: Jasbir S
authors.initials: JS
authors.lastname: Arora
authors.forename: Ian A
authors.initials: IA
authors.lastname: Blair
mesh_terms: D018736:DNA Adducts / Q000138:chemical synthesis*; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry*; D005229:Fatty Acids, Monounsaturated / Q000737:chemistry*; D015227:Lipid Peroxidation
chemical_list: C418762:9,12-dioxo-10-dodecenoic acid; D018736:DNA Adducts; D005229:Fatty Acids, Monounsaturated; C054579:1,N(2)-ethenodeoxyguanosine; D003849:Deoxyguanosine