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Izawa K, Tsuda M, Suzuki T, Honma M, Sugiyama KI. Detection of in vivo mutagenicity in rat liver samples using error-corrected sequencing techniques. Genes Environ 2023; 45:30. [PMID: 37993952 PMCID: PMC10664353 DOI: 10.1186/s41021-023-00288-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 11/14/2023] [Indexed: 11/24/2023] Open
Abstract
BACKGROUND Mutagenicity, the ability of chemical agents to cause mutations and potentially lead to cancer, is a critical aspect of substance safety assessment for protecting human health and the environment. Metabolic enzymes activate multiple mutagens in living organisms, thus in vivo animal models provide highly important information for evaluating mutagenicity in human. Rats are considered suitable models as they share a similar metabolic pathway with humans for processing toxic chemical and exhibit higher responsiveness to chemical carcinogens than mice. To assess mutagenicity in rats, transgenic rodents (TGRs) are widely used for in vivo gene mutation assays. However, such assays are labor-intensive and could only detect transgene mutations inserted into the genome. Therefore, introducing a technology to directly detect in vivo mutagenicity in rats would be necessary. The next-generation sequencing (NGS) based error-corrected sequencing technique is a promising approach for such purposes. RESULTS We investigated the applicability of paired-end and complementary consensus sequencing (PECC-Seq), an error-corrected sequencing technique, for detecting in vivo mutagenicity in the rat liver samples. PECC-Seq allows for the direct detection of ultra-rare somatic mutations in the genomic DNA without being constrained by the genomic locus, tissue, or organism. We tested PECC-Seq feasibility in rats treated with diethylnitrosamine (DEN), a mutagenic compound. Interestingly, the mutation and mutant frequencies between PECC-Seq and the TGR assay displayed a promising correlation. Our results also demonstrated that PECC-Seq could successfully detect the A:T > T:A mutation in rat liver samples, consistent with the TGR assay. Furthermore, we calculated the trinucleotide mutation frequency and proved that PECC-Seq accurately identified the DEN treatment-induced mutational signatures. CONCLUSIONS Our study provides the first evidence of using PECC-Seq for in vivo mutagenicity detection in rat liver samples. This approach could provide a valuable alternative to conventional TGR assays as it is labor- and time-efficient and eliminates the need for transgenic rodents. Error-corrected sequencing techniques, such as PECC-Seq, represent promising approaches for enhancing mutagenicity assessment and advancing regulatory science.
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Affiliation(s)
- Kazuki Izawa
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 3-25-26, Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan.
| | - Masataka Tsuda
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 3-25-26, Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan
| | - Takayoshi Suzuki
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 3-25-26, Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan
| | - Masamitsu Honma
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 3-25-26, Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan
- Division of General Affairs, National Institute of Health Sciences, 3-25-26, Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan
| | - Kei-Ichi Sugiyama
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 3-25-26, Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan
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Bercu JP, Zhang S, Sobol Z, Escobar PA, Van P, Schuler M. Comparison of the transgenic rodent mutation assay, error corrected next generation duplex sequencing, and the alkaline comet assay to detect dose-related mutations following exposure to N-nitrosodiethylamine. MUTATION RESEARCH. GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2023; 891:503685. [PMID: 37770142 DOI: 10.1016/j.mrgentox.2023.503685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 08/17/2023] [Accepted: 08/23/2023] [Indexed: 10/03/2023]
Abstract
N-Nitrosodiethylamine (NDEA), a well-studied N-nitrosamine, was tested in rats to compare the dose-response relationship of three genotoxicity endpoints. Mutant / mutation frequencies were determined using the transgenic rodent (TGR) gene mutation assay and error corrected next generation sequencing (ecNGS) (i.e., duplex sequencing (DS)), and genetic damage was detected by the alkaline comet assay. Big Blue® (cII Locus) animals (n = 6 per dose group) were administered doses of 0.001, 0.01, 0.1, 1, 3 mg/kg/day NDEA by oral gavage. Samples were collected for cII mutation and DS analyses following 28-days of exposure and 3 days recovery. In a separate study, male Sprague-Dawley (SD) rats (n = 6 per dose group) were administered the same doses by oral gavage for two consecutive days and then samples collected for the alkaline comet assay. A dose-related increase in mutant / mutation frequencies of the liver but not duodenum was observed using the TGR assay and DS with DS resulting in a slightly more sensitive response, with a lower benchmark dose (BMD). In addition, a dose-related increase in percent tail DNA was observed in the liver using the alkaline comet assay. Therefore, DS and comet assays showed good utility for hazard identification and dose-response analysis of a representative N-nitrosamine comparable to the TGR gene mutation assay.
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Affiliation(s)
- Joel P Bercu
- Gilead Sciences, Inc., Nonclinical Safety and Pathobiology (NSP), Foster City, CA 94404, USA.
| | - Shaofei Zhang
- Pfizer Research, Development, and Medical, Groton, CT, USA.
| | | | | | - Phu Van
- TwinStrand Biosciences, Inc., Seattle, WA, USA
| | - Maik Schuler
- Pfizer Research, Development, and Medical, Groton, CT, USA
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3
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Menz J, Götz ME, Gündel U, Gürtler R, Herrmann K, Hessel-Pras S, Kneuer C, Kolrep F, Nitzsche D, Pabel U, Sachse B, Schmeisser S, Schumacher DM, Schwerdtle T, Tralau T, Zellmer S, Schäfer B. Genotoxicity assessment: opportunities, challenges and perspectives for quantitative evaluations of dose-response data. Arch Toxicol 2023; 97:2303-2328. [PMID: 37402810 PMCID: PMC10404208 DOI: 10.1007/s00204-023-03553-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 06/21/2023] [Indexed: 07/06/2023]
Abstract
Genotoxicity data are mainly interpreted in a qualitative way, which typically results in a binary classification of chemical entities. For more than a decade, there has been a discussion about the need for a paradigm shift in this regard. Here, we review current opportunities, challenges and perspectives for a more quantitative approach to genotoxicity assessment. Currently discussed opportunities mainly include the determination of a reference point (e.g., a benchmark dose) from genetic toxicity dose-response data, followed by calculation of a margin of exposure (MOE) or derivation of a health-based guidance value (HBGV). In addition to new opportunities, major challenges emerge with the quantitative interpretation of genotoxicity data. These are mainly rooted in the limited capability of standard in vivo genotoxicity testing methods to detect different types of genetic damage in multiple target tissues and the unknown quantitative relationships between measurable genotoxic effects and the probability of experiencing an adverse health outcome. In addition, with respect to DNA-reactive mutagens, the question arises whether the widely accepted assumption of a non-threshold dose-response relationship is at all compatible with the derivation of a HBGV. Therefore, at present, any quantitative genotoxicity assessment approach remains to be evaluated case-by-case. The quantitative interpretation of in vivo genotoxicity data for prioritization purposes, e.g., in connection with the MOE approach, could be seen as a promising opportunity for routine application. However, additional research is needed to assess whether it is possible to define a genotoxicity-derived MOE that can be considered indicative of a low level of concern. To further advance quantitative genotoxicity assessment, priority should be given to the development of new experimental methods to provide a deeper mechanistic understanding and a more comprehensive basis for the analysis of dose-response relationships.
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Affiliation(s)
- Jakob Menz
- Department of Food Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany.
| | - Mario E Götz
- Department of Food Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Ulrike Gündel
- Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Rainer Gürtler
- Department of Food Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Kristin Herrmann
- Department of Pesticides Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Stefanie Hessel-Pras
- Department of Food Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Carsten Kneuer
- Department of Pesticides Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Franziska Kolrep
- Department of Safety in the Food Chain, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Dana Nitzsche
- Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Ulrike Pabel
- Department of Safety in the Food Chain, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Benjamin Sachse
- Department of Food Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Sebastian Schmeisser
- Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - David M Schumacher
- Department of Safety in the Food Chain, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Tanja Schwerdtle
- German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Tewes Tralau
- Department of Pesticides Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Sebastian Zellmer
- Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Bernd Schäfer
- Department of Food Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
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4
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Bercu JP, Masuda-Herrera M, Trejo-Martin A, Sura P, Jolly R, Kenyon M, Thomas R, Ponting DJ, Snodin D, Tuschl G, Simon S, De Vlieger K, Hutchinson R, Czich A, Glowienke S, Reddy MV, Johanssen S, Vock E, Claude N, Weaver RJ. Acceptable Intakes (AIs) for 11 Small molecule N-nitrosamines (NAs). Regul Toxicol Pharmacol 2023:105415. [PMID: 37257751 DOI: 10.1016/j.yrtph.2023.105415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/21/2023] [Accepted: 05/07/2023] [Indexed: 06/02/2023]
Abstract
Low levels of N-nitrosamines (NAs) were detected in pharmaceuticals and, as a result, health authorities (HAs) have published acceptable intakes (AIs) in pharmaceuticals to limit potential carcinogenic risk. The rationales behind the AIs have not been provided to understand the process for selecting a TD50 or read-across analog. In this manuscript we evaluated the toxicity data for eleven common NAs in a comprehensive and transparent process consistent with ICH M7. This evaluation included substances which had datasets that were robust, limited but sufficient, and substances with insufficient experimental animal carcinogenicity data. In the case of robust or limited but sufficient carcinogenicity information, AIs were calculated based on published or derived TD50s from the most sensitive organ site. In the case of insufficient carcinogenicity information, available carcinogenicity data and structure activity relationships (SARs) were applied to categorical-based AIs of 1500 ng/day, 150 ng/day or 18 ng/day; however additional data (such as biological or additional computational modelling) could inform an alternative AI. This approach advances the methodology used to derive AIs for NAs.
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Affiliation(s)
- Joel P Bercu
- Gilead Sciences, Inc., Nonclinical Safety and Pathobiology (NSP), Foster City, CA, USA.
| | - Melisa Masuda-Herrera
- Gilead Sciences, Inc., Nonclinical Safety and Pathobiology (NSP), Foster City, CA, USA
| | | | - Priyanka Sura
- Gilead Sciences, Inc., Nonclinical Safety and Pathobiology (NSP), Foster City, CA, USA
| | | | - Michelle Kenyon
- Pfizer Worldwide Research, Development and Medical, Drug Safety Research and Development, Eastern Point Road, Groton, CT, USA
| | - Rob Thomas
- Lhasa Limited, Granary Wharf House, 2 Canal Wharf, Leeds, UK
| | - David J Ponting
- Lhasa Limited, Granary Wharf House, 2 Canal Wharf, Leeds, UK
| | | | - Gregor Tuschl
- Merck KGaA, Global Chemical and Preclinical Safety, Darmstadt, Germany
| | - Stephanie Simon
- Merck KGaA, Global Chemical and Preclinical Safety, Darmstadt, Germany
| | | | | | | | | | | | - Sandra Johanssen
- Bayer AG, Pharmaceuticals, Research & Development, Berlin, Germany
| | - Esther Vock
- Boehringer Ingelheim Pharma GmbH & Co. KG, Birkendorfer Str., Biberach an der Riss, Germany
| | - Nancy Claude
- Servier Paris-Saclay R&D Institute, Gif-sur-Yvette, France
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5
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Toxicology and carcinogenesis studies of di(2-ethylhexyl) phthalate administered in feed to Sprague Dawley (Hsd:Sprague Dawley SD) rats. NATIONAL TOXICOLOGY PROGRAM TECHNICAL REPORT SERIES 2021:NTP-TR-601. [PMID: 35073286 DOI: 10.22427/ntp-tr-601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Di(2-ethylhexyl) phthalate (DEHP) is a member of the phthalate ester chemical class that occurs commonly in the environment and to which humans are widely exposed. Lifetime exposure to DEHP is likely to occur, including during the in utero and early postnatal windows of development. To date, no carcinogenicity assessments of DEHP have used a lifetime exposure paradigm that includes the perinatal period (gestation and lactation). The National Toxicology Program (NTP) tested the hypothesis that exposure during the perinatal period would alter the DEHP carcinogenic response quantitatively (more neoplasms) or qualitatively (different neoplasm types). Two chronic carcinogenicity assessments of DEHP were conducted in which Sprague Dawley (Hsd:Sprague Dawley SD) rats were exposed to dosed feed containing 0, 300, 1,000, 3,000, or 10,000 ppm DEHP for 2 years using different exposure paradigms. In Study 1, groups of 45 F0 time-mated females were provided dosed feed beginning on gestation day (GD) 6 through lactation. On postnatal day (PND) 21, groups of 50 F1 rats per sex continued on the study and were provided dosed feed containing the same DEHP concentration as their respective dam for 2 years. In Study 2, groups of 50 rats per sex, aged 6 to 7 weeks at study start, were provided dosed feed containing DEHP for 2 years. (Abstract Abridged).
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6
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Naruse M, Masui R, Ochiai M, Maru Y, Hippo Y, Imai T. An organoid-based carcinogenesis model induced by in vitro chemical treatment. Carcinogenesis 2021; 41:1444-1453. [PMID: 32047892 DOI: 10.1093/carcin/bgaa011] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 01/28/2020] [Accepted: 02/07/2020] [Indexed: 12/18/2022] Open
Abstract
Animal carcinogenesis models induced by environmental chemicals have been widely used for basic and applied cancer research. However, establishment of in vitro or ex vivo models is essential for molecular mechanistic elucidation of early events in carcinogenesis, leading to clarification of the total mode of action. In the present study, to establish an organoid-based chemical carcinogenesis model, mouse organoids were treated in vitro with 4 genotoxic chemicals, e.g. ethyl methanesulfonate (EMS), acrylamide (AA), diethylnitrosamine (DEN) and 7,12-dimethylbenz[a]anthracene (DMBA) to examine their tumorigenicity after injection to nude mice. The four chemicals were reported to induce lung, liver or mammary carcinomas in mouse models. DMBA-treated mammary tissue-derived organoids with Trp53 heterozygous knockout exhibited tumorigenicity, but not those with wild-type Trp53, reflecting previous reports of corresponding animal models. Treatment of lung organoids with or without Trp53 knockout with EMS or AA resulted in carcinogenic histopathological characteristics, and the activation of oncogenic kinases was demonstrated in the nodules from the nude mouse subcutis. DEN-treated liver (biliary tract) organoids also had an increased number of similar changes. In conclusion, an ex vivo model for chemical carcinogenesis was established using normal mouse tissue-derived organoids. This model will be applied to detect early molecular events, leading to clarification of the mode of action of chemical carcinogenesis.
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Affiliation(s)
| | | | | | - Yoshiaki Maru
- Department of Molecular Carcinogenesis, Chiba Cancer Center Research Institute, Chiba 260-8717, Japan
| | - Yoshitaka Hippo
- Department of Molecular Carcinogenesis, Chiba Cancer Center Research Institute, Chiba 260-8717, Japan
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7
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Johnson GE, Dobo K, Gollapudi B, Harvey J, Kenny J, Kenyon M, Lynch A, Minocherhomji S, Nicolette J, Thybaud V, Wheeldon R, Zeller A. Permitted daily exposure limits for noteworthy N-nitrosamines. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2021; 62:293-305. [PMID: 34089278 DOI: 10.1002/em.22446] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 05/07/2021] [Accepted: 05/11/2021] [Indexed: 06/12/2023]
Abstract
A genotoxic carcinogen, N-nitrosodimethylamine (NDMA), was detected as a synthesis impurity in some valsartan drugs in 2018, and other N-nitrosamines, such as N-nitrosodiethylamine (NDEA), were later detected in other sartan products. N-nitrosamines are pro-mutagens that can react with DNA following metabolism to produce DNA adducts, such as O6 -alkyl-guanine. The adducts can result in DNA replication miscoding errors leading to GC>AT mutations and increased risk of genomic instability and carcinogenesis. Both NDMA and NDEA are known rodent carcinogens in male and female rats. The DNA repair enzyme, methylguanine DNA-methyltransferase can restore DNA integrity via the removal of alkyl groups from guanine in an error-free fashion and this can result in nonlinear dose responses and a point of departure or "practical threshold" for mutation at low doses of exposure. Following International recommendations (ICHM7; ICHQ3C and ICHQ3D), we calculated permissible daily exposures (PDE) for NDMA and NDEA using published rodent cancer bioassay and in vivo mutagenicity data to determine benchmark dose values and define points of departure and adjusted with appropriate uncertainty factors (UFs). PDEs for NDMA were 6.2 and 0.6 μg/person/day for cancer and mutation, respectively, and for NDEA, 2.2 and 0.04 μg/person/day. Both PDEs are higher than the acceptable daily intake values (96 ng for NDMA and 26.5 ng for NDEA) calculated by regulatory authorities using simple linear extrapolation from carcinogenicity data. These PDE calculations using a bench-mark approach provide a more robust assessment of exposure limits compared with simple linear extrapolations and can better inform risk to patients exposed to the contaminated sartans.
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Affiliation(s)
- George E Johnson
- Swansea University Medical School, Swansea University, Swansea, Wales, UK
| | - Krista Dobo
- Genetic Toxicology, Drug Safety Research and Development, Pfizer, Groton, Connecticut, USA
| | - Bhaskar Gollapudi
- Center for Toxicology and Mechanistic Biology, Exponent Consulting, Midland, Michigan, USA
| | | | | | - Michelle Kenyon
- Genetic Toxicology, Drug Safety Research and Development, Pfizer, Groton, Connecticut, USA
| | | | | | - John Nicolette
- Genetic, Environmental and Occupational Toxicology, AbbVie, Chicago, Illinois, USA
| | | | - Ryan Wheeldon
- Swansea University Medical School, Swansea University, Swansea, Wales, UK
| | - Andreas Zeller
- Pharmaceutical Sciences, pRED Innovation Center Basel, Hoffmann-La Roche Ltd, Basel, Switzerland
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8
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Matsushita K, Ishii Y, Kijima A, Takasu S, Kuroda K, Takagi H, Nohmi T, Ogawa K, Umemura T. Background data of 2-year-old male and female F344 gpt delta rats. J Toxicol Pathol 2020; 34:23-31. [PMID: 33627942 PMCID: PMC7890168 DOI: 10.1293/tox.2020-0060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 09/03/2020] [Indexed: 11/19/2022] Open
Abstract
Although gpt delta rats, as reporter gene-transgenic rats, were
originally developed for in vivo mutation assays, they have also been
used to evaluate chemical carcinogenesis and comprehensive toxicity. Therefore, it is
necessary to accumulate background data on carcinogenicity and general toxicity in
gpt delta rats. Here, we investigated the background data of
110-week-old male and female F344 gpt delta rats and wild-type rats.
There was no effect of reporter gene transfection on animal survival rates and body
weights during the experiment. The relative weight of male gpt delta rat
adrenals was significantly higher than that of wild-type rats, possibly due to the higher
incidence of pheochromocytoma. There were no intergenotype differences in the incidence of
nonneoplastic lesions in both sexes, including chronic progressive nephropathy and focus
of cellular alteration in the liver, which had a higher incidence in both genotypes.
Additionally, the significantly higher incidence of adrenal pheochromocytoma in male
gpt delta rats than that in wild-type rats was likely incidental
because of the lack of differences in the incidences of preneoplastic (male and female)
and neoplastic (female) adrenal lesions in both genotypes. Other neoplastic lesions in
both sexes showed no intergenotype differences in incidence rates, although large granular
lymphocytic leukemia in the spleen and Leydig cell tumors in the testes of males showed
higher incidence rates. Overall, there were no effects of reporter gene transfection on
the spectrum of spontaneous lesions in F344 gpt delta rats, thus
supporting their applicability in evaluating chemical toxicity and carcinogenicity.
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Affiliation(s)
- Kohei Matsushita
- Division of Pathology, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-9501, Japan
| | - Yuji Ishii
- Division of Pathology, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-9501, Japan
| | - Aki Kijima
- Division of Pathology, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-9501, Japan
| | - Shinji Takasu
- Division of Pathology, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-9501, Japan
| | - Ken Kuroda
- Division of Pathology, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-9501, Japan
| | - Hisayoshi Takagi
- Japan SLC, Inc., 3-5-1 Aoihigashi, Naka-ku, Hamamatsu, Shizuoka 433-8114, Japan
| | - Takehiko Nohmi
- Division of Pathology, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-9501, Japan
| | - Kumiko Ogawa
- Division of Pathology, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-9501, Japan
| | - Takashi Umemura
- Division of Pathology, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-9501, Japan.,Faculty of Animal Health Technology, Yamazaki University of Animal Health Technology, 4-7-2 Minami-Osawa, Hachioji, Tokyo 192-0364, Japan
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9
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Integration of micronucleus tests with a gene mutation assay in F344 gpt delta transgenic rats using benzo[a]pyrene. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2018; 837:1-7. [PMID: 30595204 DOI: 10.1016/j.mrgentox.2018.09.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 09/12/2018] [Accepted: 09/12/2018] [Indexed: 11/20/2022]
Abstract
Reduction of the number of animals used in in vivo genotoxicity tests is encouraged. For this purpose, we conducted integrated toxicity tests combining gene mutation assays with multiple-organ micronucleus (MN) tests (peripheral blood, bone marrow, liver, and colon) in F344 gpt delta transgenic (Tg) rats. Seven-week-old male F344 gpt delta rats were orally administered 62.5 or 125 mg/kg/day benzo[a]pyrene (B[a]P) for 28 days. One day after the final day of treatment (day 29) and three days after the final treatment (day 31), bone marrow, liver, and colon samples were collected, and mutation assays and MN tests were performed. The gpt mutant frequency (MF) significantly increased in bone marrow, liver and colon but MN induction was only significant in bone marrow but not in liver and colon. Similarly MN induction was only observed in bone marrow in non-Tg F344 rats. In peripheral blood obtained on day 4, 15, 29, 31, a time-dependent increase was observed in reticulocyte MN frequency during the treatment. Thus, our integrated method successfully detected both gene mutations and MN induction caused by B[a]P. In addition, no significant differences were observed between sampling times (day 29 versus 31), suggesting that sampling on day 29 is also valid to evaluate gene mutations. On the other hand, MN results in bone marrow and peripheral blood were different depending on the sampling day. An appropriate sampling day should be designated according to which assays are integrated. We confirmed that integration of the MN test with a gene mutation assay using F344 gpt delta Tg rats is useful to evaluate different endpoints related to genotoxicity using the same animals and to reduce animal use.
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10
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Zeller A, Pfuhler S, Albertini S, Bringezu F, Czich A, Dietz Y, Fautz R, Hewitt NJ, Kirst A, Kasper P. A critical appraisal of the sensitivity of in vivo genotoxicity assays in detecting human carcinogens. Mutagenesis 2018; 33:179-193. [DOI: 10.1093/mutage/gey005] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 03/20/2018] [Indexed: 11/13/2022] Open
Affiliation(s)
- Andreas Zeller
- Pharmaceutical Sciences, pRED Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse, Basel, Switzerland
| | - Stefan Pfuhler
- Procter & Gamble, Global Product Stewardship, Human Safety, Mason Business Centre, Mason, OH, USA
| | - Silvio Albertini
- Pharmaceutical Sciences, pRED Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse, Basel, Switzerland
| | | | - Andreas Czich
- Sanofi-Aventis Deutschland GmbH, Industriepark Hoechst, Frankfurt, Germany
| | - Yasmin Dietz
- Sanofi-Aventis Deutschland GmbH, Industriepark Hoechst, Frankfurt, Germany
| | | | | | | | - Peter Kasper
- Federal Institute for Drugs and Medical Devices (BfArM), Kurt-Georg-Kiesinger-Allee, Bonn, Germany
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11
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Nohmi T, Masumura K, Toyoda-Hokaiwado N. Transgenic rat models for mutagenesis and carcinogenesis. Genes Environ 2017; 39:11. [PMID: 28174618 PMCID: PMC5289047 DOI: 10.1186/s41021-016-0072-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 12/08/2016] [Indexed: 01/18/2023] Open
Abstract
Rats are a standard experimental animal for cancer bioassay and toxicological research for chemicals. Although the genetic analyses were behind mice, rats have been more frequently used for toxicological research than mice. This is partly because they live longer than mice and induce a wider variety of tumors, which are morphologically similar to those in humans. The body mass is larger than mice, which enables to take samples from organs for studies on pharmacokinetics or toxicokinetics. In addition, there are a number of chemicals that exhibit marked species differences in the carcinogenicity. These compounds are carcinogenic in rats but not in mice. Such examples are aflatoxin B1 and tamoxifen, both are carcinogenic to humans. Therefore, negative mutagenic/carcinogenic responses in mice do not guarantee that the chemical is not mutagenic/carcinogenic to rats or perhaps to humans. To facilitate research on in vivo mutagenesis and carcinogenesis, several transgenic rat models have been established. In general, the transgenic rats for mutagenesis are treated with chemicals longer than transgenic mice for more exact examination of the relationship between mutagenesis and carcinogenesis. Transgenic rat models for carcinogenesis are engineered mostly to understand mechanisms underlying chemical carcinogenesis. Here, we review papers dealing with the transgenic rat models for mutagenesis and carcinogenesis, and discuss the future perspective.
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Affiliation(s)
- Takehiko Nohmi
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo, 158-8501 Japan
- Present address: Biological Safety Research Center, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo, 158-8501 Japan
| | - Kenichi Masumura
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo, 158-8501 Japan
| | - Naomi Toyoda-Hokaiwado
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo, 158-8501 Japan
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Onami S, Cho YM, Toyoda T, Akagi JI, Fujiwara S, Ochiai R, Tsujino K, Nishikawa A, Ogawa K. Orally administered glycidol and its fatty acid esters as well as 3-MCPD fatty acid esters are metabolized to 3-MCPD in the F344 rat. Regul Toxicol Pharmacol 2015; 73:726-31. [PMID: 26520183 DOI: 10.1016/j.yrtph.2015.10.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Revised: 10/21/2015] [Accepted: 10/22/2015] [Indexed: 10/22/2022]
Abstract
IARC has classified glycidol and 3-monochloropropane-1,2-diol (3-MCPD) as group 2A and 2B, respectively. Their esters are generated in foodstuffs during processing and there are concerns that they may be hydrolyzed to the carcinogenic forms in vivo. Thus, we conducted two studies. In the first, we administered glycidol and 3-MCPD and associated esters (glycidol oleate: GO, glycidol linoleate: GL, 3-MCPD dipalmitate: CDP, 3-MCPD monopalmitate: CMP, 3-MCPD dioleate: CDO) to male F344 rats by single oral gavage. After 30 min, 3-MCPD was detected in serum from all groups. Glycidol was detected in serum from the rats given glycidol or GL and CDP and CDO in serum from rats given these compounds. In the second, we examined if metabolism occurs on simple reaction with rat intestinal contents (gastric, duodenal and cecal contents) from male F344 gpt delta rats. Newly produced 3-MCPD was detected in all gut contents incubated with the three 3-MCPD fatty acid esters and in gastric and duodenal contents incubated with glycidol and in duodenal and cecal contents incubated with GO. Although our observation was performed at 1 time point, the results showed that not only 3-MCPD esters but also glycidol and glycidol esters are metabolized into 3-MCPD in the rat.
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Affiliation(s)
- Saeko Onami
- Division of Pathology, National Institute of Health Sciences, 1-18-1, Kamiyoga, Setagaya-ku, Tokyo, 158-8501, Japan; Pathogenetic Veterinary Science, United Graduate School of Veterinary Sciences, Gifu University, 1-1, Yanagido, Gifu, 501-1193, Japan
| | - Young-Man Cho
- Division of Pathology, National Institute of Health Sciences, 1-18-1, Kamiyoga, Setagaya-ku, Tokyo, 158-8501, Japan
| | - Takeshi Toyoda
- Division of Pathology, National Institute of Health Sciences, 1-18-1, Kamiyoga, Setagaya-ku, Tokyo, 158-8501, Japan
| | - Jun-ichi Akagi
- Division of Pathology, National Institute of Health Sciences, 1-18-1, Kamiyoga, Setagaya-ku, Tokyo, 158-8501, Japan
| | - Satoshi Fujiwara
- Division of Pharmaceutical and Life Sciences, Shimadzu Techno-Research Inc., 1, Nishinokyo-Shimoaicho, Nakagyo-ku, Kyoto, 604-8436, Japan
| | - Ryosuke Ochiai
- Division of Pharmaceutical and Life Sciences, Shimadzu Techno-Research Inc., 1, Nishinokyo-Shimoaicho, Nakagyo-ku, Kyoto, 604-8436, Japan
| | - Kazushige Tsujino
- Division of Pharmaceutical and Life Sciences, Shimadzu Techno-Research Inc., 1, Nishinokyo-Shimoaicho, Nakagyo-ku, Kyoto, 604-8436, Japan
| | - Akiyoshi Nishikawa
- Pathogenetic Veterinary Science, United Graduate School of Veterinary Sciences, Gifu University, 1-1, Yanagido, Gifu, 501-1193, Japan; Biological Safety Research Center, National Institute of Health Sciences, 1-18-1, Kamiyoga, Setagaya-ku, Tokyo, 158-8501, Japan
| | - Kumiko Ogawa
- Division of Pathology, National Institute of Health Sciences, 1-18-1, Kamiyoga, Setagaya-ku, Tokyo, 158-8501, Japan.
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Development and validation of a new transgenic hairless albino mouse as a mutational model for potential assessment of photocarcinogenicity. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2015; 791:42-52. [PMID: 26338542 DOI: 10.1016/j.mrgentox.2015.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 07/31/2015] [Accepted: 08/01/2015] [Indexed: 11/24/2022]
Abstract
Short-term phototoxicity testing is useful in selecting test agents for the longer and more expensive photocarcinogenesis safety tests; however, no validated short-term tests have been proven reliable in predicting the outcome of a photocarcinogenesis safety test. A transgenic, hairless, albino (THA) mouse model was developed that carries the gpt and red/gam [Spi(-)] genes from the gpt delta mouse background and the phenotypes from the SKH-1 mouse background to use as a short-term test in lieu of photocarcinogenesis safety tests. Validation of the THA mouse model was confirmed by exposing groups of male mice to sub-erythemal doses of ultraviolet B (UVB) irradiation for three consecutive days emitted from calibrated overhead, Kodacel-filtered fluorescent lamps and measuring the mutant frequencies (MFs) in the gpt and red/gam (Spi(-)) genes and types of mutations in the gpt gene. The doses or irradiation were monitored with broad-spectrum dosimeters that were calibrated to a NIST-traceable standard and cumulative CIE-weighted doses were 20.55 and 41.0mJ/cm(2) (effective). Mice were sacrificed 14 days after the final UVB exposure and MFs in both the gpt and red/gam genes were evaluated in the epidermis. The exposure of mice to UVB induced significant ten- to twelve-fold increases in the gpt MF and three- to five-fold increases in the Spi(-) MF over their respective background MF, 26±3×10(-6) and 9±1×10(-6). The gpt mutation spectra were significantly different between that of the UVB-irradiated and that of non-irradiated mice although the mutation spectra of both groups were dominated by C→T transitions (84% and 66%). In mice exposed to UVB, the C→T transitions occurred almost exclusively at dipyrimidine sites (92%), whereas in non-irradiated control mice, the C→T transitions occurred at CpG sites (86%). These results suggest that the newly developed THA mice are a useful and reliable model for testing UVB-induced mutagenicity in skin tissue. The application of this model for short-term prediction of solar-induced skin carcinogenicity is presently under investigation.
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