DNA Interstrand Cross-Linking Activity of (1-Chloroethenyl)oxirane, a Metabolite of β-chloroprene

Abstract

With the goal of elucidating the molecular and cellular mechanisms of chloroprene toxicity, we examined the potential DNA cross-linking of the bifunctional chloroprene metabolite, (1-chloroethenyl)oxirane (CEO). We used denaturing polyacrylamide gel electrophoresis to monitor possible formation of interstrand cross-links by CEO within synthetic DNA duplexes. Our data suggest interstrand cross-linking at deoxyguanosine residues within 5′-GC and 5′-GGC sites, with the rate of cross-linking depending on pH (pH 5.0 > pH 6.0 > pH 7.0). A comparison of the crosslinking efficiencies of CEO and the structurally similar cross-linkers diepoxybutane (DEB) and epichlorohydrin (ECH) revealed that DEB > CEO ≥ ECH. Furthermore, we found that cytotoxicity correlates with cross-linking efficiency, supporting a role for interstrand cross-links in the genotoxicology of chloroprene.

A method for the simultaneous determination of mercapturic acids as biomarkers of exposure to 2-chloroprene and epichlorohydrin in human urine

“…In vivo, the formation of DNA and protein adducts has already been shown. Besides, due to its bifunctionality, epichlorohydrin can cause crosslinks between nucleophilic side chains of biological molecules, which illustrates the major genotoxic potential of this substance [8][9][10].…”

Diepoxybutane interstrand cross-links induce DNA bending

“…The 30mer in this family has been shown previously to be efficiently cross-linked by DEB and related compounds [21]. Interstrand cross-links were purified via denaturing PAGE by excising the lowest mobility band, which was verified to contain dG-to-dG linkages at central distal deoxyguanosines via piperidine treatment and subsequent analysis of the fragments through denaturing PAGE (data not shown; for similar studies, see [9]).…”

DNA Interstrand Cross-Linking Agents and their Chemotherapeutic Potential

“…13) [22]. Epichlorhydrin 47 as well as the related epibromohydrin 48 proved the crosslinking ability that was monitored by using denaturing polyacrylamide gel electrophoresis [21].…”

“…The R- The bifunctional chloroprene metabolite, (1-chloroethenyl) oxirane 49 also turned out to be an efficient cross-linking agent. In a recent study Wadugu et al suggested a possible mechanism for the formation of cross-link through oxirane 49 (Scheme 1) [22]. The nucleophilic attack on the protonated epoxide by the N 7 of a deoxyguanosine residue affords N7-(3-chloro-2-hydroxy-3-buten-1-yl)guanine.…”