The formation of substituted 1,N6-etheno-2'-deoxyadenosine and 1,N2-etheno-2'-deoxyguanosine adducts by cis-2-butene-1,4-dial, a reactive metabolite of furan.
Furan is an environmental chemical that induces liver toxicity and tumor formation in rodents, leading to its classification as a probable human carcinogen. cis-2-Butene-1,4-dial, the metabolite considered responsible for furan's toxicological effects, is mutagenic in the Ames assay and reacts with 2'-deoxycytidine (dCyd), 2'-deoxyadenosine (dAdo), and 2'-deoxyguanosine (dGuo) to form previously characterized diastereomeric adducts. The initially formed dCyd adducts are stable to rearrangement, while the dAdo and dGuo adducts are unstable and rearrange to form secondary products. On the basis of UV absorbance, fluorescence, 1H NMR, and mass spectral data, the rearrangement product of the dAdo adduct was identified as the substituted etheno-dAdo adduct, 1''-[3-(2'-deoxy-beta-D-erythropentafuranosyl)-3H-imidazo[2,1-i]purin-8-yl]ethane-2''-al. The NMR characterization of the O-methyloxime derivative of the secondary dGuo adduct, along with mass spectral and UV data on the underivatized adduct, allowed for its structural assignment as the substituted etheno-dGuo compound, 3-(2'-deoxy-beta-D-erythropentafuranosyl)imidazo-7-(ethane-2''-al)[1,2-alpha]purine-9-one. The characterization of the primary and secondary products formed in the reaction of cis-2-butene-1,4-dial with nucleosides is important for understanding the mechanism of furan-induced carcinogenesis. These secondary adducts retain a reactive aldehyde with the potential to form cross-links and are likely to contribute significantly to furan's toxic and carcinogenic effects.
Byrns
Michael C
MC
Division of Environmental Health Sciences and Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Vu
Choua C
CC
Peterson
Lisa A
LA
D000447:Aldehydes / Q000737:chemistry* / Q000378:metabolism; D018736:DNA Adducts / Q000737:chemistry* / Q000378:metabolism / Q000633:toxicity; D003839:Deoxyadenosines / Q000737:chemistry* / Q000378:metabolism; D005663:Furans / Q000378:metabolism* / Q000633:toxicity
D000447:Aldehydes; D018736:DNA Adducts; D003839:Deoxyadenosines; D005663:Furans; C015977:malealdehyde; C032221:1,N(6)-ethenodeoxyadenosine; C039281:furan