Formation of fused-ring 2'-deoxycytidine adducts from 1-chloro-3-buten-2-one, an in vitro 1,3-butadiene metabolite, under in vitro physiological conditions

Chem Res Toxicol. 2013 Oct 21;26(10):1545-53. doi: 10.1021/tx4002435. Epub 2013 Sep 25.

Abstract

1-Chloro-3-buten-2-one (CBO) is a potential metabolite of 1,3-butadiene (BD), a carcinogenic air pollutant. CBO is a bifunctional alkylating agent that readily reacts with glutathione (GSH) to form mono-GSH and di-GSH adducts. Recently, CBO and its precursor 1-chloro-2-hydroxy-3-butene (CHB) were found to be cytotoxic and genotoxic in human liver cells in culture with CBO being approximately 100-fold more potent than CHB. In the present study, CBO was shown to react readily with 2'-deoxycytidine (dC) under in vitro physiological conditions (pH 7.4, 37 °C) to form four dC adducts with the CBO moieties forming fused rings with the N3 and N(4) atoms of dC. The four products were structurally characterized as 2-hydroxy-2-hydroxymethyl-7-(2-deoxy-β-d-erythro-pentofuranosyl)-1,2,3,4-tetrahydro-6-oxo-6H,7H-pyrimido[1,6-a]pyrimidin-5-ium (dC-1 and dC-2, a pair of diastereomers), 4-chloromethyl-4-hydroxy-7-(2-deoxy-β-d-erythro-pentofuranosyl)-1,2,3,4-tetrahydro-6-oxo-6H,7H-pyrimido[1,6-a]pyrimidin-5-ium (dC-3), and 2-chloromethyl-2-hydroxy-7-(2-deoxy-β-d-erythro-pentofuranosyl)-1,2,3,4-tetrahydro-6-oxo-6H,7H-pyrimido[1,6-a]pyrimidin-5-ium (dC-4). Interestingly, dC-1 and dC-2 were stable under our experimental conditions (pH 7.4, 37 °C, and 6 h) and existed in equilibrium as indicated by HPLC analysis, whereas dC-3 and dC-4 were labile with the half-lives being 3.0 ± 0.36 and 1.7 ± 0.06 h, respectively. Decomposition of dC-4 produced both dC-1 and dC-2, whereas acid hydrolysis of dC-1/dC-2 and dC-4 in 1 M HCl at 100 °C for 30 min yielded the deribosylated adducts dC-1H/dC-2H and dC-4H, respectively. Because fused-ring dC adducts of other chemicals are mutagenic, the characterized CBO-dC adducts could be mutagenic and play a role in the cytotoxicity and genotoxicity of CBO and its precursors, CHB and BD. The CBO-dC adducts may also be used as standards to characterize CBO-DNA adducts and to develop potential biomarkers for CBO formation in vivo.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomarkers / metabolism
  • Butadienes / chemistry
  • Butadienes / metabolism*
  • Butanones / chemistry*
  • Butanones / metabolism
  • Butanones / toxicity
  • Cell Line
  • Chromatography, High Pressure Liquid
  • DNA Adducts / chemistry*
  • DNA Damage / drug effects
  • Deoxycytidine / chemistry*
  • Deoxycytidine / metabolism
  • Humans
  • Hydrogen-Ion Concentration
  • Hydrolysis
  • Spectrometry, Mass, Electrospray Ionization
  • Temperature
  • Time Factors

Substances

  • 1-chloro-3-buten-2-one
  • Biomarkers
  • Butadienes
  • Butanones
  • DNA Adducts
  • Deoxycytidine
  • 1,3-butadiene