Mutagenesis Advance Access originally published online on March 8, 2009
Mutagenesis 2009 24(3):279-284; doi:10.1093/mutage/gep007
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Genotoxicity of 3,6-dinitrobenzo[e]pyrene, a novel mutagen in ambient air and surface soil, in mammalian cells in vitro and in vivo
Environmental Genetics Laboratory, Frontier Science Innovation Center and Graduate School of Science, Osaka Prefecture University, 1-2 Gakuen-cho Naka-ku, Sakai 599-8570, Japan 1Department of Public Health, Kyoto Pharmaceutical University, 5 Misasagi Nakauchicho, Yamashina-ku, Kyoto 607-8414, Japan 2Laboratory of Virology, Osaka Prefectural Institute of Public Health, 3-69 Nakamachi 1-chome, Higashinari-ku, Osaka, 537-0025, Japan
3,6-Dinitrobenzo[e]pyrene (3,6-DNBeP), newly identified in airborne particles and surface soil, is a potent mutagen in Salmonella typhimurium. The present study investigated the genotoxic potency of 3,6-DNBeP in vitro and in vivo using mammalian cell strains (Chinese hamster CHL/IU and human HepG2) and ICR mice, respectively. In the hprt gene mutation assay using HepG2 cells, the spontaneous mutant frequency was 61.1 per 105 clonable cells, which increased to 229 per 105 clonable cells after treatment with 1.0 µg/ml (3 µM) 3,6-DNBeP. Notably, in HepG2 cells with increased N-acetyltransferase 2 activity, the mutant frequency increased to 648 per 105 clonable cells by treatment of 1.0 µg/ml (3 µM) 3,6-DNBeP. The sister chromatid exchange frequency increased approximately three times the control level in HepG2 cells treated with 3,6-DNBeP at a concentration of 1.0 µg/ml (3 µM). In HepG2 and CHL/IU cells, the frequency of the cells with micronuclei was 0.9 and 1.2%, and the frequencies increased to 2.3 and 7.6% after 1.0 µg/ml (3 µM) 3,6-DNBeP-treatment, respectively. The H2AX phosphorylation level increased 8-fold compared with the background level with 1.0 µg/ml (3 µM) 3,6-DNBeP-treatment in HepG2 cells. Moreover, the comet assay showed that 3,6-DNBeP produced DNA damage in the cells of liver, kidney, lung and bone marrow in ICR mice 3 h after intraperitoneal injection at 40 mg/kg (0.12 mmol/kg) body weight. These data indicate that 3,6-DNBeP is genotoxic to mammalian cells in vitro and in vivo.
* To whom correspondence should be addressed. Tel: +81 72 254 9862; Fax: +81 72 254 9938; Email: yagi-t{at}riast.osakafu-u.ac.jp
Received on January 14, 2009; revised on February 5, 2009; accepted on February 5, 2009.