title: Genotoxicity of 3-nitrobenzanthrone and 3-aminobenzanthrone in MutaMouse and lung epithelial cells derived from MutaMouse.
abstract: FE1 lung epithelial cells derived from MutaMouse are a new model system to provide in vitro mutagenicity data with the potential to predict the outcome of an in vivo MutaMouse test. 3-Nitrobenzanthrone (3-NBA) is a potent mutagen and suspected human carcinogen identified in diesel exhaust and urban air pollution. We investigated the mutagenicity and DNA binding of 3-NBA and its main metabolite 3-aminobenzanthrone (3-ABA) in vitro and in vivo in the MutaMouse assay. Mice were treated with 3-NBA or 3-ABA (0, 2 or 5 mg/kg body weight/day) by gavage for 28 days and 28 days later lacZ mutant frequency (MF) was determined in liver, lung and bone marrow. For both compounds, dose-related increases in MF were seen in liver and bone marrow, but not in lung; mutagenic activity was approximately 2-fold lower for 3-ABA than for 3-NBA. With 3-NBA, highest DNA adduct levels (measured by (32)P-post-labelling) were found in liver (approximately 230 adducts per 10(8) nucleotides) with levels 20- to 40-fold lower in bone marrow and lung. With 3-ABA, DNA adduct levels were again highest in the liver, but approximately 4-fold lower than for 3-NBA. FE1 cells were exposed to up to 10 microg/ml 3-NBA or 3-ABA for 6 h with or without exogenous activation (S9) and harvested after 3 days. For 3-NBA, there was a dose-related increase in MF both with and without S9 mix, which was >10 times higher than observed in vivo. At the highest concentration of 3-ABA (10 microg/ml), we found only around a 2-fold increase in MF relative to controls. DNA adduct formation in FE1 cells was dose-dependent for both compounds, but 10- to 20-fold higher for 3-NBA compared to 3-ABA. Collectively, our data indicate that MutaMouse FE1 cells are well suited for cost-effective testing of suspected mutagens with different metabolic activation pathways as a guide for subsequent in vivo MutaMouse testing.
authors.affiliation: Section of Molecular Carcinogenesis, Institute of Cancer Research, Brookes Lawley Building, Sutton, Surrey SM2 5NG, UK. volker.arlt@icr.ac.uk
authors.forename: Volker M
authors.initials: VM
authors.lastname: Arlt
authors.forename: John
authors.initials: J
authors.lastname: Gingerich
authors.forename: Heinz H
authors.initials: HH
authors.lastname: Schmeiser
authors.forename: David H
authors.initials: DH
authors.lastname: Phillips
authors.forename: George R
authors.initials: GR
authors.lastname: Douglas
authors.forename: Paul A
authors.initials: PA
authors.lastname: White
mesh_terms: D000818:Animals; D001551:Benz(a)Anthracenes / Q000633:toxicity*; D002478:Cells, Cultured; D018736:DNA Adducts; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism; D007763:Lac Operon; D008168:Lung / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D009152:Mutagenicity Tests; D009153:Mutagens / Q000633:toxicity*
chemical_list: C475568:3-aminobenzanthrone; D001551:Benz(a)Anthracenes; D018736:DNA Adducts; D009153:Mutagens; C117220:3-nitrobenzanthrone