title: Myeloperoxidase--463A variant reduces benzo[a]pyrene diol epoxide DNA adducts in skin of coal tar treated patients.
abstract: The skin of atopic dermatitis patients provides an excellent model to study the role of inflammation in benzo[a]pyrene (BaP) activation, since these individuals are often topically treated with ointments containing high concentrations of BaP. In this study we have determined, by HPLC with fluorescence detection, the BaP diol epoxide (BPDE)-DNA adduct levels in human skin after topical treatment with coal tar and their modulation by the -463G-->A myeloperoxidase (MPO) polymorphism, which reduces MPO mRNA expression. BPDE-DNA adduct levels were 2.2 and 14.2 adducts/10(8) nt for MPO-463AA/AG and -463GG, respectively. The predominant BaP tetrol observed was tetrol I-1, which is derived after hydrolysis of the anti-BPDE-DNA adduct. The tetrol I-1/II-2 ratio, corresponding to the anti/syn ratio, was 6.7. The (32)P-post-labeling assay was also performed and thin layer chromatograms showed a major spot with a chromatographic location corresponding to BPDE-DNA. The mean values of the BPDE-DNA adduct spots were 3.8 +/- 2.4 per 10(8) nt for MPO-463AA/AG (n = 3) and 18.4 +/- 11.0 per 10(8) nt for MPO-463GG (n = 7), respectively (P = 0.03). One individual with the homozygous mutant genotype (-463AA) even had a 13-fold lower adduct level (1.4 per 10(8) nt) as compared to MPO-463GG subjects. In conclusion, these data show for the first time: (i) the in vivo formation of BPDE-DNA adducts in human skin treated with coal tar; (ii) that the MPO-463AA/AG genotype reduced BPDE-DNA adduct levels in human skin.
authors.affiliation: German Cancer Research Center (DKFZ), Division of Toxicology and Cancer Risk Factors, PO Box 101949, D-69009 Heidelberg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Rojas
authors.forename: R
authors.initials: R
authors.lastname: Godschalk
authors.forename: K
authors.initials: K
authors.lastname: Alexandrov
authors.forename: I
authors.initials: I
authors.lastname: Cascorbi
authors.forename: E
authors.initials: E
authors.lastname: Kriek
authors.forename: J
authors.initials: J
authors.lastname: Ostertag
authors.forename: F J
authors.initials: FJ
authors.lastname: Van Schooten
authors.forename: H
authors.initials: H
authors.lastname: Bartsch
mesh_terms: D015123:7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide / Q000633:toxicity*; D000293:Adolescent; D000328:Adult; D001711:Biotransformation; D003033:Coal Tar / Q000009:adverse effects*; D004247:DNA / Q000187:drug effects*; D018736:DNA Adducts / Q000378:metabolism* / Q000493:pharmacokinetics; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009153:Mutagens / Q000633:toxicity*; D009195:Peroxidase / Q000378:metabolism*; D011110:Polymorphism, Genetic; D012867:Skin / Q000201:enzymology / Q000378:metabolism*
chemical_list: D018736:DNA Adducts; D009153:Mutagens; D015123:7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide; D003033:Coal Tar; D004247:DNA; D009195:Peroxidase