title: Isotope Dilution nanoLC/ESI+-HRMS3Quantitation of Urinary N7-(1-Hydroxy-3-buten-2-yl) Guanine Adducts in Humans and Their Use as Biomarkers of Exposure to 1,3-Butadiene.
abstract: 1,3-Butadiene (BD) is an important industrial and environmental chemical classified as a known human carcinogen. Occupational exposure to BD in the polymer and monomer industries is associated with an increased incidence of lymphoma. BD is present in automobile exhaust, cigarette smoke, and forest fires, raising concern about potential exposure of the general population to this carcinogen. Following inhalation exposure, BD is bioactivated to 3,4-epoxy-1-butene (EB). If not detoxified, EB is capable of modifying guanine and adenine bases of DNA to form nucleobase adducts, which interfere with accurate DNA replication and cause cancer-initiating mutations. We have developed a nanoLC/ESI+-HRMS3methodology for N7-(1-hydroxy-3-buten-2-yl) guanine (EB-GII) adducts in human urine (limit of detection: 0.25 fmol/mL urine; limit of quantitation: 1.0 fmol/mL urine). This new method was successfully used to quantify EB-GII in urine of F344 rats treated with 0-200 ppm of BD, occupationally exposed workers, and smokers belonging to two different ethnic groups. EB-GII amounts increased in a dose-dependent manner in urine of laboratory rats exposed to 0, 62.5, or 200 ppm of BD. Urinary EB-GII levels were significantly increased in workers occupationally exposed to 0.1-2.2 ppm of BD (1.25 ± 0.51 pg/mg of creatinine) as compared to administrative controls exposed to <0.01 ppm of BD (0.22 ± 0.08 and pg/mg of creatinine) (p = 0.0024), validating the use of EB-GII as a biomarker of human exposure to BD. EB-GII was also detected in smokers' urine with European American smokers excreting significantly higher amounts of EB-GII than African American smokers (0.48 ± 0.09 vs 0.12 ± 0.02 pg/mg of creatinine, p = 3.1 × 10-7). Interestingly, small amounts of EB-GII were observed in animals and humans with no known exposure to BD, providing preliminary evidence for its endogenous formation. Urinary EB-GII adduct levels and urinary mercapturic acids of BD (MHBMA, DHBMA) were compared in a genotyped multiethnic smoker cohort.
authors.forename: Dewakar
authors.initials: D
authors.lastname: Sangaraju
authors.forename: Emily J
authors.initials: EJ
authors.lastname: Boldry
authors.affiliation: Division of Biostatistics, Keck School of Medicine and Children's Cancer Group, University of Southern California , Los Angeles, California 90089, United States.
authors.forename: Yesha M
authors.initials: YM
authors.lastname: Patel
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Vermont , Burlington, Vermont 05405, United States.
authors.forename: Vernon
authors.initials: V
authors.lastname: Walker
authors.forename: Irina
authors.identifier: 0000-0001-5140-8944
authors.initials: I
authors.lastname: Stepanov
authors.affiliation: Division of Biostatistics, Keck School of Medicine and Children's Cancer Group, University of Southern California , Los Angeles, California 90089, United States.
authors.forename: Daniel
authors.initials: D
authors.lastname: Stram
authors.forename: Dorothy
authors.initials: D
authors.lastname: Hatsukami
authors.forename: Natalia
authors.identifier: 0000-0002-0621-6860
authors.initials: N
authors.lastname: Tretyakova
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000652:urine*; D002070:Butadienes / Q000633:toxicity*; D002851:Chromatography, High Pressure Liquid; D005006:Ethnicity; D006147:Guanine / Q000652:urine; D006801:Humans; D007201:Indicator Dilution Techniques; D013058:Mass Spectrometry / Q000379:methods*; D051381:Rats; D011916:Rats, Inbred F344; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D015415:Biomarkers; D002070:Butadienes; C120608:N-7-(1-hydroxy-3-buten-2-yl)guanine; D006147:Guanine; C031763:1,3-butadiene