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Ma M, Liang J. Voltammetric detection of 2-aminoazotoluene based on electropolymerization of β-cyclodextrin. Chem Pap 2023. [DOI: 10.1007/s11696-023-02680-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Douglas GR, Beevers C, Gollapudi B, Keig‐Shevlin Z, Kirkland D, O'Brien JM, van Benthem J, Yauk CL, Young RR, Marchetti F. Impact of sampling time on the detection of mutations in rapidly proliferating tissues using transgenic rodent gene mutation models: A review. Environ Mol Mutagen 2022; 63:376-388. [PMID: 36271823 PMCID: PMC10099936 DOI: 10.1002/em.22514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 10/13/2022] [Accepted: 10/20/2022] [Indexed: 06/16/2023]
Abstract
The OECD Test Guideline 488 (TG 488) for the Transgenic Rodent Gene Mutation Assay has undergone several revisions to update the recommended design for studying mutations in somatic tissues and male germ cells. The recently revised TG recommends a single sampling time of 28 days following 28 days of exposure (i.e., 28 + 28 days) for all tissues, irrespective of proliferation rates. An alternative design (i.e., 28 + 3 days) is appropriate when germ cell data is not required, nor considered. While the 28 + 28 days design is clearly preferable for slowly proliferating somatic tissues and germ cells, there is still uncertainty about the impact of extending the sampling time to 28 days for rapidly somatic tissues. Here, we searched the available literature for evidence supporting the applicability and utility of the 28 + 28 days design for rapidly proliferating tissues. A total of 79 tests were identified. When directly comparing results from both designs in the same study, there was no evidence that the 28 + 28 days regimen resulted in a qualitatively different outcome from the 28 + 3 days design. Studies with a diverse range of agents that employed only a 28 + 28 days protocol provide further evidence that this design is appropriate for rapidly proliferating tissues. Benchmark dose analyses demonstrate high quantitative concordance between the 28 + 3 and 28 + 28 days designs for rapidly proliferating tissues. Accordingly, our review confirms that the 28 + 28 days design is appropriate to assess mutagenicity in both slowly and rapidly proliferating somatic tissues, and germ cells, and provides further support for the recommended design in the recently adopted TG 488.
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Affiliation(s)
| | | | | | | | | | | | - Jan van Benthem
- National Institute for the Netherlands Public Health and the EnvironmentBilthovenThe Netherlands
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Hakura A, Koyama N, Seki Y, Sonoda J, Asakura S. o-Aminoazotoluene, 7,12-dimethylbenz[a]anthracene, and N-ethyl-N-nitrosourea, which are mutagenic but not carcinogenic in the colon, rapidly induce colonic tumors in mice with dextran sulfate sodium-induced colitis. Genes Environ 2022; 44:11. [PMID: 35351212 PMCID: PMC8966303 DOI: 10.1186/s41021-022-00240-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 03/09/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Several rodent models with chemically induced colon cancer have been developed. Among these models, dextran sulfate sodium (DSS), a colitis inducer, combined with azoxymethane as a colon mutagenic carcinogen, is commonly used. We previously reported that although benzo [a] pyrene (BP) is mutagenic but not carcinogenic in the colon, it rapidly develops colon tumors at a high incidence/multiplicity after treatment with DSS. In the present study, we examined whether other colon-mutagenic non-carcinogens (CMNCs) induced colon tumors after treatment with DSS. RESULTS o-Aminoazotoluene, 7,12-dimethylbenz[a]anthracene, and N-ethyl-N-nitrosourea were selected as CMNCs. Male CD2F1 mice were orally administered CMNC for 5 consecutive days. After a 9-day dose-free period, mice were treated with 4% DSS in drinking water for 1 week. Three months after DSS treatment, colon samples were collected for histopathology and β-catenin immunohistochemistry analyses. All CMNCs in combination with DSS induced colonic adenocarcinomas at a high incidence/multiplicity in the distal and middle parts of the colon, coinciding with the location of colitis. Unlike in normal cells where β-catenin is exclusively located on the cell membrane, in adenocarcinoma cells, it was translocated to both the nucleus and cytoplasm or only to cytoplasm. The translocation of β-catenin is closely associated with colon carcinogenesis in rodents and humans. No colonic tumors or dysplastic lesions were found after exposure to either CMNC or DSS alone. CONCLUSION We provided further evidence clearly showing that CMNCs can rapidly induce colonic tumors in mice with DSS-induced colitis, even if they are not colonic carcinogens.
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Affiliation(s)
- Atsushi Hakura
- Global Drug Safety, Eisai Co., Ltd., 5-1-3 Tokodai, Tsukuba, Ibaraki, 300-2635, Japan.
| | - Naoki Koyama
- Global Drug Safety, Eisai Co., Ltd., 5-1-3 Tokodai, Tsukuba, Ibaraki, 300-2635, Japan
| | - Yuki Seki
- Global Drug Safety, Eisai Co., Ltd., 5-1-3 Tokodai, Tsukuba, Ibaraki, 300-2635, Japan
| | - Jiro Sonoda
- Global Drug Safety (present affiliation, Advanced Data Assurance), Eisai Co., Ltd., 5-1-3 Tokodai, Tsukuba, Ibaraki, 300-2635, Japan
| | - Shoji Asakura
- Global Drug Safety, Eisai Co., Ltd., 5-1-3 Tokodai, Tsukuba, Ibaraki, 300-2635, Japan
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Marchetti F, Aardema MJ, Beevers C, van Benthem J, Godschalk R, Williams A, Yauk CL, Young R, Douglas GR. Identifying germ cell mutagens using OECD test guideline 488 (transgenic rodent somatic and germ cell gene mutation assays) and integration with somatic cell testing. Mutation Research/Genetic Toxicology and Environmental Mutagenesis 2018; 832-833:7-18. [DOI: 10.1016/j.mrgentox.2018.05.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 05/28/2018] [Accepted: 05/28/2018] [Indexed: 01/15/2023]
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Morozkova TS, Bogdanova LA, Semenov DE, Zhukova NA, Popova NA. PT/Y Mice Are Sensitive to the Inhibitory Effect of o-Aminoazotoluene on Glucocorticoid Induction of Tyrosine Aminotransferase and Its Hepatocarcinogenic Effect. Bull Exp Biol Med 2015; 158:789-93. [PMID: 25894779 DOI: 10.1007/s10517-015-2863-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Indexed: 11/28/2022]
Abstract
PT/Y mice used for studies of the effects of mutagens are characterized by the absence of spontaneous tumors of the liver, but often develop these tumors in response to chronic oaminoazotoluene treatment. The level of glucocorticoid induction of adaptive hepatic enzyme tyrosine aminotransferase decreases by more than 70% 24 h after acute injection of o-aminoazotoluene to these animals. These mice can serve as a model for studies of the relationship between the effect of carcinogens on the regulation of activity of adaptive hepatic enzymes and their capacity to induce the development of liver tumors.
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Affiliation(s)
- T S Morozkova
- Research Institute of Regional Pathology and Pathomorphology, Siberian Division of the Russian Academy of Medical Sciences, Novosibirsk, Russia,
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Kaledin VI, Il'nitskaya SI, Popova NA, Bogdanova LA. Suppression of sulfoconjugation reduces the protective effect of ortho-aminoazotoluene on hepatocarcinogenesis induced by diethylnitrosamine in mice. Bull Exp Biol Med 2014; 157:368-70. [PMID: 25065317 DOI: 10.1007/s10517-014-2568-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Indexed: 10/25/2022]
Abstract
The effects of ortho-aminoazotoluene on carcinogenic activity of diethylnitrosamine were studied in CBA and ICR mice. Injection of ortho-aminoazotoluene before and after diethylnitrosamine led to a significant reduction of its anticarcinogenic effect, judging from significantly lower level of liver tumors. Pentachlorophenol, inhibitor of sulfotransferase (catalyzing the terminal stage of ortho-aminoazotoluene metabolic activity), stimulated its carcinogenic effect on mouse liver. On the other hand, pentachlorophenol reduced the protective effect of ortho-aminoazotoluene on diethylnitrosamine-induced hepatocarcinogenesis in mice. Presumably, the carcinogenic and anticarcinogenic effects of ortho-aminoazotoluene were realized by its initial form or intermediate (non-sulfated) metabolites.
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Affiliation(s)
- V I Kaledin
- Institute of Cytology and Genetics, Siberian Division of the Russian Academy of Sciences, Novosibirsk, Russia,
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Wu Y, Qi X, Gong L, Xing G, Chen M, Miao L, Yao J, Suzuki T, Furihata C, Luan Y, Ren J. Identification of BC005512 as a DNA damage responsive murine endogenous retrovirus of GLN family involved in cell growth regulation. PLoS One 2012; 7:e35010. [PMID: 22514700 PMCID: PMC3325921 DOI: 10.1371/journal.pone.0035010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Accepted: 03/08/2012] [Indexed: 01/22/2023] Open
Abstract
Genotoxicity assessment is of great significance in drug safety evaluation, and microarray is a useful tool widely used to identify genotoxic stress responsive genes. In the present work, by using oligonucleotide microarray in an in vivo model, we identified an unknown gene BC005512 (abbreviated as BC, official full name: cDNA sequence BC005512), whose expression in mouse liver was specifically induced by seven well-known genotoxins (GTXs), but not by non-genotoxins (NGTXs). Bioinformatics revealed that BC was a member of the GLN family of murine endogenous retrovirus (ERV). However, the relationship to genotoxicity and the cellular function of GLN are largely unknown. Using NIH/3T3 cells as an in vitro model system and quantitative real-time PCR, BC expression was specifically induced by another seven GTXs, covering diverse genotoxicity mechanisms. Additionally, dose-response and linear regression analysis showed that expression level of BC in NIH/3T3 cells strongly correlated with DNA damage, measured using the alkaline comet assay,. While in p53 deficient L5178Y cells, GTXs could not induce BC expression. Further functional studies using RNA interference revealed that down-regulation of BC expression induced G1/S phase arrest, inhibited cell proliferation and thus suppressed cell growth in NIH/3T3 cells. Together, our results provide the first evidence that BC005512, a member from GLN family of murine ERV, was responsive to DNA damage and involved in cell growth regulation. These findings could be of great value in genotoxicity predictions and contribute to a deeper understanding of GLN biological functions.
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Affiliation(s)
- Yuanfeng Wu
- Center for Drug Safety Evaluation and Research, State Key Laboratory of New Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Xinming Qi
- Center for Drug Safety Evaluation and Research, State Key Laboratory of New Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Likun Gong
- Center for Drug Safety Evaluation and Research, State Key Laboratory of New Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Guozhen Xing
- Center for Drug Safety Evaluation and Research, State Key Laboratory of New Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Min Chen
- Center for Drug Safety Evaluation and Research, State Key Laboratory of New Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Lingling Miao
- Center for Drug Safety Evaluation and Research, State Key Laboratory of New Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Jun Yao
- Center for Drug Safety Evaluation and Research, State Key Laboratory of New Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Takayoshi Suzuki
- Division of Cellular and Gene Therapy Products, National Institute of Health Sciences, Tokyo, Japan
| | - Chie Furihata
- Department of Chemistry and Biological Science, School of Science and Engineering, Aoyama Gakuin University, Kanagawa, Japan
| | - Yang Luan
- Center for Drug Safety Evaluation and Research, State Key Laboratory of New Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- * E-mail: (YL); (JR)
| | - Jin Ren
- Center for Drug Safety Evaluation and Research, State Key Laboratory of New Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- * E-mail: (YL); (JR)
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Smetanina MA, Pakharukova MY, Kurinna SM, Dong B, Hernandez JP, Moore DD, Merkulova TI. Ortho-aminoazotoluene activates mouse constitutive androstane receptor (mCAR) and increases expression of mCAR target genes. Toxicol Appl Pharmacol 2011; 255:76-85. [PMID: 21672546 PMCID: PMC3148291 DOI: 10.1016/j.taap.2011.05.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Revised: 05/15/2011] [Accepted: 05/28/2011] [Indexed: 10/18/2022]
Abstract
2'-3-dimethyl-4-aminoazobenzene (ortho-aminoazotoluene, OAT) is an azo dye and a rodent carcinogen that has been evaluated by the International Agency for Research on Cancer (IARC) as a possible (class 2B) human carcinogen. Its mechanism of action remains unclear. We examined the role of the xenobiotic receptor Constitutive Androstane Receptor (CAR, NR1I3) as a mediator of the effects of OAT. We found that OAT increases mouse CAR (mCAR) transactivation in a dose-dependent manner. This effect is specific because another closely related azo dye, 3'-methyl-4-dimethyl-aminoazobenzene (3'MeDAB), did not activate mCAR. Real-time Q-PCR analysis in wild-type C57BL/6 mice revealed that OAT induces the hepatic mRNA expression of the following CAR target genes: Cyp2b10, Cyp2c29, Cyp3a11, Ugt1a1, Mrp4, Mrp2 and c-Myc. CAR-null (Car(-/-)) mice showed no increased expression of these genes following OAT treatment, demonstrating that CAR is required for their OAT dependent induction. The OAT-induced CAR-dependent increase of Cyp2b10 and c-Myc expression was confirmed by Western blotting. Immunohistochemistry analysis of wild-type and Car(-/-) livers showed that OAT did not acutely induce hepatocyte proliferation, but at much later time points showed an unexpected CAR-dependent proliferative response. These studies demonstrate that mCAR is an OAT xenosensor, and indicate that at least some of the biological effects of this compound are mediated by this nuclear receptor.
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Affiliation(s)
- Mariya A Smetanina
- Department of Molecular and Cellular Biology, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, USA.
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Eremeev AV, Timofeeva OA, Goloshchapov AV, Il'nitskaya SI, Merkulova TI, Kaledin VI, Setkov NA. O-aminoazotoluene suppresses hepatocyte proliferation in inbred mice susceptible to hepatocarcinogenesis. Dokl Biol Sci 2009; 428:479-83. [PMID: 19994796 DOI: 10.1134/s0012496609050251] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- A V Eremeev
- Voino-Yasenetsky Krasnoyarsk State Medical University, Krasnoyarsk, Russia
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Timofeeva OA, Eremeev AV, Goloshchapov AN, Ilnitskaya SI, Merculova TI, Kaledin VI, Setkov NA. Orto-aminoazotoluen induces the expression of the p53 gene in inbred strains of mice susceptible and resistant to hepatocarcinogenesis. Dokl Biol Sci 2009; 429:579-582. [PMID: 20170078 DOI: 10.1134/s0012496609060271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2009] [Indexed: 05/28/2023]
Affiliation(s)
- O A Timofeeva
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch, Russian Academy of Sciences, pr. Akademika Lavrent'eva 8, Novosibirsk 630090, Russia
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Timofeeva OA, Eremeev AV, Goloshchapov A, Kalashnikova E, Ilnitskaya S, Setkov NA, Kobzev V, Buzard GS, Filipenko ML, Kaledin VI, Merkulova TI. Effects of o-aminoazotoluene on liver regeneration and p53 activation in mice susceptible and resistant to hepatocarcinogenesis. Toxicology 2008; 254:91-6. [DOI: 10.1016/j.tox.2008.09.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2008] [Revised: 09/10/2008] [Accepted: 09/15/2008] [Indexed: 01/08/2023]
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Jagger C, Tate M, Cahill PA, Hughes C, Knight AW, Billinton N, Walmsley RM. Assessment of the genotoxicity of S9-generated metabolites using the GreenScreen HC GADD45a-GFP assay. Mutagenesis 2008; 24:35-50. [DOI: 10.1093/mutage/gen050] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Lambert IB, Singer TM, Boucher SE, Douglas GR. Detailed review of transgenic rodent mutation assays. Mutat Res 2005; 590:1-280. [PMID: 16081315 DOI: 10.1016/j.mrrev.2005.04.002] [Citation(s) in RCA: 247] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2005] [Revised: 04/04/2005] [Accepted: 04/12/2005] [Indexed: 11/17/2022]
Abstract
Induced chromosomal and gene mutations play a role in carcinogenesis and may be involved in the production of birth defects and other disease conditions. While it is widely accepted that in vivo mutation assays are more relevant to the human condition than are in vitro assays, our ability to evaluate mutagenesis in vivo in a broad range of tissues has historically been quite limited. The development of transgenic rodent (TGR) mutation models has given us the ability to detect, quantify, and sequence mutations in a range of somatic and germ cells. This document provides a comprehensive review of the TGR mutation assay literature and assesses the potential use of these assays in a regulatory context. The information is arranged as follows. (1) TGR mutagenicity models and their use for the analysis of gene and chromosomal mutation are fully described. (2) The principles underlying current OECD tests for the assessment of genotoxicity in vitro and in vivo, and also nontransgenic assays available for assessment of gene mutation, are described. (3) All available information pertaining to the conduct of TGR assays and important parameters of assay performance have been tabulated and analyzed. (4) The performance of TGR assays, both in isolation and as part of a battery of in vitro and in vivo short-term genotoxicity tests, in predicting carcinogenicity is described. (5) Recommendations are made regarding the experimental parameters for TGR assays, and the use of TGR assays in a regulatory context.
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Affiliation(s)
- Iain B Lambert
- Mutagenesis Section, Environmental Health Sciences Bureau, Healthy Environments and Consumer Safety Branch, 0803A, Health Canada, Ottawa, Ont., Canada K1A 0L2.
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Mikhailova ON, Vasyunina EA, Ovchinnikova LP, Gulyaeva LF, Timofeeva OA, Filipenko ML, Kaledin VI. o-Aminoazotoluene does induce the enzymes of its own mutagenic activation in mouse liver. Toxicology 2005; 211:132-8. [PMID: 15863256 DOI: 10.1016/j.tox.2005.03.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2005] [Revised: 03/11/2005] [Accepted: 03/14/2005] [Indexed: 11/26/2022]
Abstract
The objective of this study was to investigate the CYP1A1 and CYP1A2 mRNAs and enzyme activities in mouse liver during induction with o-aminoazotoluene (OAT) as well as the capability of the hepatic S9-fraction from OAT-treated mice to induce its own activation to mutagens in the Ames test using S. typhymurium strain TA98. The data obtained indicate that when used at appropriate doses, OAT is a PAH-type inducer of mouse hepatic microsomal monooxygenases, which activity is not less than that of the known inducer 3,4-benzo[alpha]pyrene. In the absence of S9-fraction enzymes no OAT-mediated mutagenicity was observed in the Ames test. In the presence of the S9-fraction from OAT-pretreated mice, OAT induced as high revertant numbers, as it did in the presence of the S9 fraction from the liver of Aroclor 1254-treated mice. Thus, OAT does induce the enzymes of its own mutagenic activation in mouse liver.
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Affiliation(s)
- Olga N Mikhailova
- Laboratory of Molecular Mechanisms of Carcinogenesis, Institute of Molecular Biology and Biophysics, Timakov Street 2, Novosibirsk 630117, Russia.
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Kohara A, Suzuki T, Honma M, Hirano N, Ohsawa K, Ohwada T, Hayashi M. Mutation spectrum of o-aminoazotoluene in the cII gene of lambda/lacZ transgenic mice (MutaMouse). Mutat Res 2001; 491:211-20. [PMID: 11287313 DOI: 10.1016/s1383-5718(01)00143-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The o-aminoazotoluene (AAT) has been evaluated as a possible human carcinogen by the International Agency for Research on Cancer. In rodents, it is carcinogenic mainly in the liver, and also in lung following long term administration. We previously examined in lambda/lacZ transgenic mice for the induction of lacZ mutations in liver, lung, urinary bladder, colon, kidney, bone marrow, and testis. AAT induced gene mutations strongly in the liver and colon. In the present report, we reveal the molecular nature of mutations induced by AAT in the lambda cII gene (the cII gene, a phenotypically selectable marker in the lambda transgene, has 294bp, which makes it easier to sequence than the original target, the 3kb lacZ gene). The cII mutant frequency in liver and colon was five and nine times higher, respectively, in AAT-treated mice than in control mice. Sequence analysis revealed that AAT induced G:C to T:A transversions, whereas spontaneous mutations consisted primarily of G:C to A:T transitions at CpG sites.
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Affiliation(s)
- A Kohara
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, 158-8501, Tokyo, Japan
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