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Gi M, Suzuki S, Kanki M, Yokohira M, Tsukamoto T, Fujioka M, Vachiraarunwong A, Qiu G, Guo R, Wanibuchi H. A novel support vector machine-based 1-day, single-dose prediction model of genotoxic hepatocarcinogenicity in rats. Arch Toxicol 2024; 98:2711-2730. [PMID: 38762666 DOI: 10.1007/s00204-024-03755-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Accepted: 03/27/2024] [Indexed: 05/20/2024]
Abstract
The development of a rapid and accurate model for determining the genotoxicity and carcinogenicity of chemicals is crucial for effective cancer risk assessment. This study aims to develop a 1-day, single-dose model for identifying genotoxic hepatocarcinogens (GHCs) in rats. Microarray gene expression data from the livers of rats administered a single dose of 58 compounds, including 5 GHCs, was obtained from the Open TG-GATEs database and used for the identification of marker genes and the construction of a predictive classifier to identify GHCs in rats. We identified 10 gene markers commonly responsive to all 5 GHCs and used them to construct a support vector machine-based predictive classifier. In the silico validation using the expression data of the Open TG-GATEs database indicates that this classifier distinguishes GHCs from other compounds with high accuracy. To further assess the model's effectiveness and reliability, we conducted multi-institutional 1-day single oral administration studies on rats. These studies examined 64 compounds, including 23 GHCs, with gene expression data of the marker genes obtained via quantitative PCR 24 h after a single oral administration. Our results demonstrate that qPCR analysis is an effective alternative to microarray analysis. The GHC predictive model showed high accuracy and reliability, achieving a sensitivity of 91% (21/23) and a specificity of 93% (38/41) across multiple validation studies in three institutions. In conclusion, the present 1-day single oral administration model proves to be a reliable and highly sensitive tool for identifying GHCs and is anticipated to be a valuable tool in identifying and screening potential GHCs.
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Affiliation(s)
- Min Gi
- Department of Environmental Risk Assessment, Graduate School of Medicine, Osaka Metropolitan University, Osaka, 545-8585, Japan
- Department of Molecular Pathology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, 545-8585, Japan
| | - Shugo Suzuki
- Department of Molecular Pathology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, 545-8585, Japan
| | - Masayuki Kanki
- Department of Molecular Pathology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, 545-8585, Japan
| | - Masanao Yokohira
- Department of Medical Education, Faculty of Medicine, Kagawa University, Miki-cho, Kita-gun, Kagawa, 761-0793, Japan
- Department of Pathology and Host-Defense, Faculty of Medicine, Kagawa University, Miki-cho, Kita-gun, Kagawa, 761-0793, Japan
| | - Tetsuya Tsukamoto
- Department of Diagnostic Pathology, Graduate School of Medicine, Fujita Health University, Toyoake, Aichi, 470-1192, Japan
| | - Masaki Fujioka
- Department of Molecular Pathology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, 545-8585, Japan
| | - Arpamas Vachiraarunwong
- Department of Environmental Risk Assessment, Graduate School of Medicine, Osaka Metropolitan University, Osaka, 545-8585, Japan
| | - Guiyu Qiu
- Department of Molecular Pathology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, 545-8585, Japan
| | - Runjie Guo
- Department of Environmental Risk Assessment, Graduate School of Medicine, Osaka Metropolitan University, Osaka, 545-8585, Japan
| | - Hideki Wanibuchi
- Department of Molecular Pathology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, 545-8585, Japan.
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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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Arnesdotter E, Rogiers V, Vanhaecke T, Vinken M. An overview of current practices for regulatory risk assessment with lessons learnt from cosmetics in the European Union. Crit Rev Toxicol 2021; 51:395-417. [PMID: 34352182 DOI: 10.1080/10408444.2021.1931027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Risk assessments of various types of chemical compounds are carried out in the European Union (EU) foremost to comply with legislation and to support regulatory decision-making with respect to their safety. Historically, risk assessment has relied heavily on animal experiments. However, the EU is committed to reduce animal experimentation and has implemented several legislative changes, which have triggered a paradigm shift towards human-relevant animal-free testing in the field of toxicology, in particular for risk assessment. For some specific endpoints, such as skin corrosion and irritation, validated alternatives are available whilst for other endpoints, including repeated dose systemic toxicity, the use of animal data is still central to meet the information requirements stipulated in the different legislations. The present review aims to provide an overview of established and more recently introduced methods for hazard assessment and risk characterisation for human health, in particular in the context of the EU Cosmetics Regulation (EC No 1223/2009) as well as the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) Regulation (EC 1907/2006).
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Affiliation(s)
- Emma Arnesdotter
- Department of Pharmaceutical and Pharmacological Sciences, Research Group of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel, Brussels, Belgium
| | - Vera Rogiers
- Department of Pharmaceutical and Pharmacological Sciences, Research Group of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel, Brussels, Belgium
| | - Tamara Vanhaecke
- Department of Pharmaceutical and Pharmacological Sciences, Research Group of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel, Brussels, Belgium
| | - Mathieu Vinken
- Department of Pharmaceutical and Pharmacological Sciences, Research Group of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel, Brussels, Belgium
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Nohmi T. Thresholds of Genotoxic and Non-Genotoxic Carcinogens. Toxicol Res 2018; 34:281-290. [PMID: 30370002 PMCID: PMC6195886 DOI: 10.5487/tr.2018.34.4.281] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 08/10/2018] [Accepted: 08/30/2018] [Indexed: 12/19/2022] Open
Abstract
Exposure to chemical agents is an inevitable consequence of modern society; some of these agents are hazardous to human health. The effects of chemical carcinogens are of great concern in many countries, and international organizations, such as the World Health Organization, have established guidelines for the regulation of these chemicals. Carcinogens are currently categorized into two classes, genotoxic and non-genotoxic carcinogens, which are subject to different regulatory policies. Genotoxic carcinogens are chemicals that exert carcinogenicity via the induction of mutations. Owing to their DNA interaction properties, there is thought to be no safe exposure threshold or dose. Genotoxic carcinogens are regulated under the assumption that they pose a cancer risk for humans, even at very low doses. In contrast, non-genotoxic carcinogens, which induce cancer through mechanisms other than mutations, such as hormonal effects, cytotoxicity, cell proliferation, or epigenetic changes, are thought to have a safe exposure threshold or dose; thus, their use in society is permitted unless the exposure or intake level would exceed the threshold. Genotoxicity assays are an important method to distinguish the two classes of carcinogens. However, some carcinogens have negative results in in vitro bacterial mutation assays, but yield positive results in the in vivo transgenic rodent gene mutation assay. Non-DNA damage, such as spindle poison or topoisomerase inhibition, often leads to positive results in cytogenetic genotoxicity assays such as the chromosome aberration assay or the micronucleus assay. Therefore, mechanistic considerations of tumor induction, based on the results of the genotoxicity assays, are necessary to distinguish genotoxic and non-genotoxic carcinogens. In this review, the concept of threshold of toxicological concern is introduced and the potential risk from multiple exposures to low doses of genotoxic carcinogens is also discussed.
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Affiliation(s)
- Takehiko Nohmi
- Division of Pathology, Biological Safety Research Center, National Institute of Health Sciences, Kanagawa, Japan
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Suzuki T, Matsumoto K, Honma M, Nohmi T. Impact of DNA polymerase ζ mutations on genotoxic thresholds of oxidative mutagens. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2018; 828:10-14. [PMID: 29555059 DOI: 10.1016/j.mrgentox.2018.02.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Revised: 01/31/2018] [Accepted: 02/02/2018] [Indexed: 12/11/2022]
Abstract
In regulatory genetic toxicology, it is an axiom that there is no threshold for genotoxicity of chemicals, such that genotoxic chemicals may impose carcinogenic risk on humans even at very low doses. This paradigm is counterintuitive, however, because humans possess a number of self-defense mechanisms that may suppress the genotoxicity at these low doses and therefore manifest a practical threshold. DNA polymerase zeta (Pol ζ) is a specialized Pol that plays an important role in DNA synthesis across DNA damage, thereby modulating cell survival and genotoxicity. In this study, we compared the sensitivity of three types of human cells: D2781N, L2618M, and their wild-type (WT) cells, to the low dose effects of genotoxicity of the oxidizing agents, potassium bromate (KBrO3) and sodium dichromate (Na2Cr2O7). D2781N cells express a variant form of Pol ζ, whose activity is weaker than that of the WT enzyme. L2618M cells express another variant form of Pol ζ, whose fidelity of DNA replication is lower than that of the WT enzyme. D2781N exhibited the highest sensitivity for TK gene mutation and micronucleus (MN) formation and displayed the lowest practical threshold for MN induction by KBrO3. In contrast, L2618M exhibited the lowest practical threshold for sister-chromatid exchange (SCE) induction by both chemicals. These results suggest that Pol ζ mutations have significant impacts on practical thresholds of genotoxicity; the factors affecting the practical threshold can differ depending on the endpoint of genotoxicity. Roles of the variant forms of Pol ζ in genotoxicity by the oxidizing agents are discussed.
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Affiliation(s)
- Tetsuya Suzuki
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Kyomu Matsumoto
- Toxicology Division, The Institute of Environmental Toxicology, 4321 Uchimoriya, Joso-shi, Ibaraki, 303-0043, Japan
| | - Masamitsu Honma
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Takehiko Nohmi
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan.
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Fukushima S, Kasai T, Umeda Y, Ohnishi M, Sasaki T, Matsumoto M. Carcinogenicity of multi-walled carbon nanotubes: challenging issue on hazard assessment. J Occup Health 2018; 60:10-30. [PMID: 29046510 PMCID: PMC5799097 DOI: 10.1539/joh.17-0102-ra] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 09/10/2017] [Indexed: 01/20/2023] Open
Abstract
OBJECTIVES This report reviews the carcinogenicity of multi-walled carbon nanotubes (MWCNTs) in experimental animals, concentrating on MWNT-7, a straight fibrous MWCNT. METHODS MWCNTs were administered to mice and rats by intraperitoneal injection, intrascrotal injection, subcutaneous injection, intratracheal instillation and inhalation. RESULTS Intraperitoneal injection of MWNT-7 induced peritoneal mesothelioma in mice and rats. Intrascrotal injection induced peritoneal mesothelioma in rats. Intratracheal instillation of MWCNT-N (another straight fibrous MWCNT) induced both lung carcinoma and pleural mesothelioma in rats. In the whole body inhalation studies, in mice MWNT-7 promoted methylcholanthrene-initiated lung carcinogenesis. In rats, inhalation of MWNT-7 induced lung carcinoma and lung burdens of MWNT-7 increased with increasing concentration of airborne MWNT-7 and increasing duration of exposure. CONCLUSIONS Straight, fibrous MWCNTs exerted carcinogenicity in experimental animals. Phagocytosis of MWCNT fibers by macrophages was very likely to be a principle factor in MWCNT lung carcinogenesis. Using no-observed-adverse-effect level-based approach, we calculated that the occupational exposure limit (OEL) of MWNT-7 for cancer protection is 0.15 μg/m3 for a human worker. Further studies on the effects of the shape and size of MWCNT fibers and mode of action on the carcinogenicity are required.
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Affiliation(s)
- Shoji Fukushima
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety
- Association for Promotion of Research on Risk Assessment
| | - Tatsuya Kasai
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety
| | - Yumi Umeda
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety
| | - Makoto Ohnishi
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety
| | - Toshiaki Sasaki
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety
| | - Michiharu Matsumoto
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety
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Harrison P, Holmes P, Bevan R, Kamps K, Levy L, Greim H. Regulatory risk assessment approaches for synthetic mineral fibres. Regul Toxicol Pharmacol 2015; 73:425-41. [DOI: 10.1016/j.yrtph.2015.07.029] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 07/30/2015] [Accepted: 07/31/2015] [Indexed: 11/28/2022]
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Strategies in case of positive in vivo results in genotoxicity testing. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2011; 723:121-8. [DOI: 10.1016/j.mrgentox.2010.09.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Accepted: 09/08/2010] [Indexed: 01/23/2023]
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