title: Mechanistic relationships between DNA adducts, oncogene mutations, and lung tumorigenesis in strain A mice.
abstract: This paper describes a series of studies on the lung tumorigenic activities of polycyclic aromatic hydrocarbons (PAHs) in strain A/J mice, their ability to form PAH-DNA adducts in lung tissues, and their ability to mutate the Ki-ras oncogene in PAH-induced tumors. Seven PAHs were studied: cyclopenta[cd]pyrene (CPP), benzo[a]pyrene (B[a]P), benzo[b]fluoranthene (B[b]F), dibenz[a,h] anthracene (DBA), 5-methylchrysene (5MC), benz[j]aceanthrylene (B[j]A), and dibenzo[a,l]pyrene (DB[a,l]P). The dose-response data for the PAHs revealed 100-fold differences in tumor potency based on dose, with the order of activity DB[a,l]P, DBA > B[j]A > 5MC > CPP B[a]P > B[b]F. Large differences in tumor multiplicity were also observed between the PAHs. DNA adducts were measured by 32P-postlabeling techniques on DNA from lungs of mice treated with these PAH's. DB[a,l]P gave syn- and anti-fjord-region diol-epoxide adducts of dAdo and dGuo; DBA gave both bay-region diol-epoxide-dGuo and bisdihydrodiol-epoxide adducts; CPP gave cyclopenta-ring-dGuo adducts; B[j]A gave a mixture of cyclopenta-ring-dGuo and -dAdo adducts; 5MC gave anti-bay-region diol-epoxide-dGuo adducts; B[a]P gave bay-region diol-epoxide-dGuo adducts; and B[b]F gave 5-hydroxy-B[b]F-diol-epoxide-dGuo adducts. Ki-ras codon 12 and 61 mutation analysis of PAH induced tumors was performed using PCR and dideoxy sequencing methods. DB[a,l]P gave both codon 12 and codon 61 mutations. High proportions of codon 12 TGT mutations from B[a]P-, B[b]F- and 5MC-, induced tumors and CGT mutations from CPP- and B[j]A-induced tumors were observed. DBA produced no mutations in Ki-ras codons 12 or 61 by direct sequencing. The interrelationships between the tumorigenesis, DNA adduct, and oncogene mutation data are discussed.
authors.affiliation: National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA. nesnow.stephen@epamail.epa.gov
authors.forename: S
authors.initials: S
authors.lastname: Nesnow
authors.forename: J A
authors.initials: JA
authors.lastname: Ross
authors.forename: M J
authors.initials: MJ
authors.lastname: Mass
authors.forename: G D
authors.initials: GD
authors.lastname: Stoner
mesh_terms: D000236:Adenoma / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D002273:Carcinogens / Q000378:metabolism / Q000633:toxicity*; D018736:DNA Adducts / Q000378:metabolism*; D004252:DNA Mutational Analysis; D017931:DNA Primers / Q000737:chemistry; D004273:DNA, Neoplasm / Q000032:analysis; D004305:Dose-Response Relationship, Drug; D011905:Genes, ras / Q000235:genetics*; D008175:Lung Neoplasms / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D008805:Mice, Inbred A; D009154:Mutation; D011084:Polycyclic Aromatic Hydrocarbons / Q000378:metabolism / Q000633:toxicity*; D016133:Polymerase Chain Reaction
chemical_list: D002273:Carcinogens; D018736:DNA Adducts; D017931:DNA Primers; D004273:DNA, Neoplasm; D011084:Polycyclic Aromatic Hydrocarbons