Novel 1,N⁶-Etheno-2‘-deoxyadenosine Adducts from Lipid Peroxidation Products

Abstract

trans,trans-2,4-Decadienal (DDE) is a widespread alpha, beta-unsaturated aldehyde found, for example, in food, water, and environmental pollutants. DDE is also endogenously generated as a breakdown product of lipid peroxidation in cell membranes. In the work presented here, the reaction of DDE with 2'-deoxyadenosine (dAdo) was investigated in an effort to assess its possible DNA damage potential. Besides 1,N(6)-etheno-2'-deoxyadenosine and two products, namely, 1-[3-(2-deoxy-beta-D-erythro-pentofuranosyl)-3H-imidazo[2, 1-i]purin-7-yl]-1,2,3-octanetriol (adduct I) and 1-[3-(2-deoxy-beta-D-erythro-pentofuranosyl)-3H-imidazo[2, 1-i]purin-7-yl]-1,2-heptanediol (adduct II), previously described by our group, two novel etheno adducts were identified. Thus, 1-[3-(2-deoxy-beta-D-erythro-pentofuranosyl)-3H-imidazo[2, 1-i]purin-7-yl]-1-hexanol (adduct III) and 1-[3-(2-deoxy-beta-D-erythro-pentofuranosyl)-3H-imidazo[2, 1-i]purin-7-yl]-2,3-epoxy-1-octanol (adduct IV) were isolated by reverse-phase high-performance liquid chromatography and characterized on the basis of extensive spectroscopic measurements. The formation of the adducts is likely to involve initial DDE oxidation followed by generation of reactive intermediates such as diepoxides, epoxides, and/or hydroperoxides. The subsequent reaction of the latter oxidation products with dAdo will give rise to the four described adducts. We also demonstrated here that upon oxidation, DDE reacts with calf thymus DNA, producing the four dAdo adducts. Interestingly, two of them are the expected products arising from the reaction of dAdo with 4-hydroxy-trans-2-nonenal (HNE) and trans-2-octenal, two other important breakdown lipid peroxidation products. The reactivity of DDE with DNA is lower than that of the latter aldehydes. However, DDE produced a wider variety of adducts. The characterization of the different DNA-etheno adducts and the determination of the mechanism of formation are of great importance for a better understanding of the deleterious biological effects associated with this class of compounds.

Antioxidative Function and Substrate Specificity of NAD(P)H- dependent Alkenal/one Oxidoreductase

“…A number of these have been shown to be cytotoxic, mutagenic, and/or carcinogenic (18,19). Short chain aliphatic 2-alkenals (such as acrolein), alkenones (such as methyl vinyl ketone), 2,4-alkadienones (such as 2,4-decadienal), and 4-hydroxy-2-alkenals (such as HNE and 4-hydroxy-2-hexenal) are thought to readily form exocyclic DNA adducts under physiological conditions (49,50). These adducts lead to mutations and are formed through the epoxidation of the ␣,␤-double bond and subsequent reaction with nucleophilic atoms of the DNA bases (12,51).…”

Structural and Kinetic Analysis of Miscoding Opposite the DNA Adduct 1,N6-Ethenodeoxyadenosine by Human Translesion DNA Polymerase η

“…Barbin et al (16) and Laib et al (17) provided evidence that etheno adducts might be involved in the carcinogenicity of vinyl chloride, a known liver carcinogen in humans. Subsequent work showed the presence of etheno DNA adducts in rats that had never been exposed to vinyl chloride (or related vinyl monomers) (18) and that the adducts are the result of lipid peroxidation (19,20). The reaction of the primary vinyl chloride oxidation product 2-chloroxirane with DNA yields 1,N 6 -ethenodeoxyadenosine (1,N 6 -⑀dA) 5 as the major etheno adduct (21), although the repair of this adduct is faster than that of some others, such that the N 2 ,3-ethenodeoxyguanosine levels become higher (22).…”

Formação de adutos exocíclicos com bases de DNA: implicações em mutagênese e carcinogênese

“…Estudos de citotoxicidade mostraram que este aldeído é um dos produtos da quebra de hidroperóxidos lipídicos mais tóxicos para células 319,320 , inibe o crescimento celular, altera o nível de glutationa celular e induz fragmentação do DNA 321 . Recentemente foram caracterizados em nosso laboratório cinco etenoadutos fluorescentes resultantes da reação de epóxidos do DDE com 2'-desoxiadenosina in vitro [322][323][324] e três etenoadutos não fluorescentes resultantes da reação de epóxidos do DDE com 2'-desoxiguanosina in vitro 325 . Todos os etenoadutos foram também detectados em DNA incubado com DDE in vitro.…”

“…Nossos resultados mostraram que DDE oxidado reage com dGuo levando à formação de vários adutos, dentre os quais três foram isolados e identificados com base em extensiva análise espectroscópica: aduto A1 (1,N 2 -eteno-2'-desoxiguanosina) e dois novos produtos diastereoisoméricos denominados adutos A2-1 e A2-2 325 . Uma das possíveis vias para formação desses adutos é o mecanismo já descrito para reações de compostos carbonílicos epoxidados com bases de ácidos nucleicos 282,283,324 . Para a formação do aduto A1 poderia haver a epoxidação inicial das duas duplas ligações do aldeído ou apenas da dupla ligação em C2.…”