title: Identification of a Fused-Ring 2'-Deoxyadenosine Adduct Formed in Human Cells Incubated with 1-Chloro-3-buten-2-one, a Potential Reactive Metabolite of 1,3-Butadiene.
abstract: 1-Chloro-3-buten-2-one (CBO) is an in vitro metabolite of 1,3-butadiene (BD), a carcinogenic air pollutant. CBO exhibited potent cytotoxicity and genotoxicity that have been attributed in part to its reactivity toward DNA. Previously, we have characterized the CBO adducts with 2'-deoxycytidine and 2'-deoxyguanosine. In the present study, we report on the reaction of CBO with 2'-deoxyadenosine (dA) under in vitro physiological conditions (pH 7.4, 37 °C). We used the synthesized standards and their decomposition and acid-hydrolysis products to characterize the CBO-DNA adducts formed in human cells. The fused-ring dA adducts (dA-1 and dA-2) were readily synthesized and were structurally characterized as 1,N(6)-(1-hydroxy-1-hydroxymethylpropan-1,3-diyl)-2'-deoxyadenosine and 1,N(6)-(1-hydroxy-1-chloromethylpropan-1,3-diyl)-2'-deoxyadenosine, respectively. dA-1 exhibited a half-life of 16.0 ± 0.7 h and decomposed to dA at pH 7.4 and 37 °C. At similar conditions, dA-2 decomposed to dA-1 and dA, and had a half-life of 0.9 ± 0.1 h. These results provide strong evidence for dA-1 being a degradation product of dA-2. dA-1 is formed by replacement of the chlorine atom of dA-2 by a hydroxyl group. The slow decomposition of dA-1 to dA, along with the detection of hydroxymethyl vinyl ketone (HMVK) as another degradation product, suggested equilibrium between dA-1 and a ring-opened carbonyl-containing intermediate that undergoes a retro-Michael reaction to yield dA and HMVK. Acid hydrolysis of dA-1 and dA-2 yielded the corresponding deribosylated products A-1D and A-2D, respectively. In the acid-hydrolyzed reaction mixture of CBO with calf thymus DNA, both A-1D and A-2D could be detected; however, the amount of A-2D was significantly larger than that of A-1D. Interestingly, only A-2D could be detected by LC-MS analysis of acid-hydrolyzed DNA from cells incubated with CBO, suggesting that dA-2 was stable in DNA and thus may play an important role in the genotoxicity and carcinogenicity of BD. In addition, A-2D could be developed as a biomarker of CBO formation in human cells.
authors.affiliation: Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University , Shanghai 200444, China.
authors.forename: Fang-Mao
authors.initials: FM
authors.lastname: Zeng
authors.affiliation: Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University , Shanghai 200444, China.
authors.forename: Ling-Yan
authors.initials: LY
authors.lastname: Liu
authors.affiliation: Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University , Shanghai 200444, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Zheng
authors.affiliation: East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences , Shanghai 200090, China.
authors.forename: Cong
authors.initials: C
authors.lastname: Kong
authors.affiliation: Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University , Shanghai 200444, China.
authors.forename: Jing
authors.initials: J
authors.lastname: An
authors.affiliation: Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University , Shanghai 200444, China.
authors.forename: Ying-Xin
authors.initials: YX
authors.lastname: Yu
authors.affiliation: Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University , Shanghai 200444, China.
authors.forename: Xin-Yu
authors.initials: XY
authors.lastname: Zhang
authors.affiliation: Department of Comparative Biosciences and the Molecular and Environmental Toxicology Center, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States.
authors.forename: Adnan A
authors.initials: AA
authors.lastname: Elfarra
mesh_terms: D000818:Animals; D002070:Butadienes / Q000737:chemistry / Q000378:metabolism*; D002074:Butanones / Q000737:chemistry* / Q000378:metabolism*; D002417:Cattle; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D018736:DNA Adducts / Q000032:analysis* / Q000737:chemistry* / Q000378:metabolism; D003839:Deoxyadenosines / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D056945:Hep G2 Cells; D006801:Humans; D015394:Molecular Structure
chemical_list: C580717:1-chloro-3-buten-2-one; D002070:Butadienes; D002074:Butanones; D018736:DNA Adducts; D003839:Deoxyadenosines; D004247:DNA; C427203:calf thymus DNA; C031763:1,3-butadiene; C058118:2'-deoxyadenosine