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Hendriks G, Adriaens E, Allemang A, Clements J, Cole G, Derr R, Engel M, Hamel A, Kidd D, Kellum S, Kiyota T, Myhre A, Naëssens V, Pfuhler S, Roy M, Settivari R, Schuler M, Zeller A, van Benthem J, Vanparys P, Kirkland D. Interlaboratory validation of the ToxTracker assay: An in vitro reporter assay for mechanistic genotoxicity assessment. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2024; 65:4-24. [PMID: 38545858 DOI: 10.1002/em.22592] [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: 11/17/2023] [Revised: 03/10/2024] [Accepted: 03/11/2024] [Indexed: 04/11/2024]
Abstract
ToxTracker is a mammalian cell reporter assay that predicts the genotoxic properties of compounds with high accuracy. By evaluating induction of various reporter genes that play a key role in relevant cellular pathways, it provides insight into chemical mode-of-action (MoA), thereby supporting discrimination of direct-acting genotoxicants and cytotoxic chemicals. A comprehensive interlaboratory validation trial was conducted, in which the principles outlined in OECD Guidance Document 34 were followed, with the primary objectives of establishing transferability and reproducibility of the assay and confirming the ability of ToxTracker to correctly classify genotoxic and non-genotoxic compounds. Reproducibility of the assay to predict genotoxic MoA was confirmed across participating laboratories and data were evaluated in terms of concordance with in vivo genotoxicity outcomes. Seven laboratories tested a total of 64 genotoxic and non-genotoxic chemicals that together cover a broad chemical space. The within-laboratory reproducibility (WLR) was up to 98% (73%-98% across participants) and the overall between-laboratory reproducibility (BLR) was 83%. This trial confirmed the accuracy of ToxTracker to predict in vivo genotoxicants with a sensitivity of 84.4% and a specificity of 91.2%. We concluded that ToxTracker is a robust in vitro assay for the accurate prediction of in vivo genotoxicity. Considering ToxTracker's robust standalone accuracy and that it can provide important information on the MoA of chemicals, it is seen as a valuable addition to the regulatory in vitro genotoxicity battery that may even have the potential to replace certain currently used in vitro battery assays.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Jan van Benthem
- National Institute for Public Health and the Environment, The Netherlands
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Enzymatic Hydrolysis of Rutin: Evaluation of Kinetic Parameters and Anti-Proliferative, Mutagenic and Anti-Mutagenic Effects. Life (Basel) 2023; 13:life13020549. [PMID: 36836907 PMCID: PMC9967632 DOI: 10.3390/life13020549] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 02/13/2023] [Accepted: 02/14/2023] [Indexed: 02/18/2023] Open
Abstract
The bioavailability of glucoside flavonoids is influenced by the nature of the sugar, glucosides being absorbed faster than rhamnoglucosides, for example. One strategy to enhance the bioavailability is enzymatic hydrolysis. In this study, some kinetic parameters of hesperidinase-mediated hydrolysis of rutin were evaluated using an UHPLC/QTOF-MSE analysis of the products of a bioconversion reaction. The resulting hydrolyzed rutins (after 4, 8 and 12 h of reaction) were submitted to anti-proliferative and Cytokinesis-Block Micronucleus (CBMN) assays in CHO-K1 cells. In the hesperidinase-mediated hydrolysis, the final concentration of quercetin-3-O-glucoside (Q3G) was directly proportional to the rutin concentration and inversely proportional to the reaction time. At an anti-proliferative concentration (2.5 μg/mL), hydrolyzed rutin derivatives did not show a mutagenic effect, except for the sample with a higher content of Q3G (after 4 h of the enzymatic hydrolysis of rutin). Moreover, the higher Q3G content in hydrolyzed rutin protected the CHO-K1 cells 92% of the time against methyl methanesulfonate-induced mutagenic damage. These results suggested that the anti-mutagenic effect of hydrolyzed rutin might be related to antioxidant and cell death induction. Presenting a good lipophilicity/hydrophilicity ratio, together with antioxidant and anti-mutagenic activities, the hesperidinase-mediated hydrolyzed rutin seemed to be a promisor raw material for the development of food supplements.
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Gomes LM, Moysés DA, Nascimento HFS, Mota TC, Bonfim LT, Cardoso PCS, Burbano RMR, Bahia MO. Genotoxic and cytotoxic effects of the drug dipyrone sodium in African green monkey kidney (Vero) cell line exposed in vitro. Naunyn Schmiedebergs Arch Pharmacol 2021; 394:1529-1535. [DOI: 10.1007/s00210-021-02078-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 03/08/2021] [Indexed: 12/13/2022]
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Igarashi T, Suzuki H, Ushida K, Matsumoto M, Inoue K, Kanno T, Miwa Y, Ishii T, Nagase T, Katsumata Y, Hirose A. Initial hazard assessment of 1,4-dichlorobutane: Genotoxicity tests, 28-day repeated-dose toxicity test, and reproductive/developmental toxicity screening test in rats. Regul Toxicol Pharmacol 2020; 112:104610. [PMID: 32032664 DOI: 10.1016/j.yrtph.2020.104610] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 01/27/2020] [Accepted: 02/01/2020] [Indexed: 11/27/2022]
Abstract
1,4-Dichlorobutane (1,4-DCB) is used as raw materials for drugs, pesticides, fragrances, and chemical fibers, and being used as a solvent. Its toxicity data was insufficient for screening assessment under the Japanese Chemical Substances Control Law. We conducted toxicity tests and hazard classification for screening assessment 1,4-DCB showed negative in the Ames test, positive in the in vitro chromosomal aberrations test with metabolic activation, and negative in the in vivo mouse bone-marrow micronucleus test. The 28-day repeated-dose toxicity study, where male and female rats were administered 1,4-DCB by gavage at 0, 12, 60, and 300 mg/kg/day, showed significant effects on the liver and pancreas from 12 mg/kg/day and kidney at 300 mg/kg/day. Based on periportal hepatocellular hypertrophy and decreased zymogen granules in pancreas, the lowest observed adverse effect level (LOAEL) of 12 mg/kg/day was obtained. The reproductive/developmental toxicity screening study, in which male and female rats were administered 1,4-DCB by gavage at dose of 0, 2.4, 12, and 60 mg/kg/day for 42-46 days, showed that the delivery index was decreased at 60 mg/kg/day without maternal toxicity. Based on the general toxicity, we classified this chemical as hazard class 2, with a D-value (Derived No Effect Level) of 0.002 mg/kg/day.
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Affiliation(s)
- Toshime Igarashi
- Division of Risk Assessment, Center for Biological Safety & Research, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan; Division of Cellular & Molecular Toxicology, Center for Biological Safety & Research, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan.
| | - Hiroshi Suzuki
- Division of Risk Assessment, Center for Biological Safety & Research, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan.
| | - Kazuo Ushida
- Division of Risk Assessment, Center for Biological Safety & Research, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan.
| | - Mariko Matsumoto
- Division of Risk Assessment, Center for Biological Safety & Research, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan.
| | - Kaoru Inoue
- Division of Risk Assessment, Center for Biological Safety & Research, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan.
| | - Takuya Kanno
- CMIC Pharma Science Co., Ltd., CMIC Bioresearch Center, 10221 Kobuchizawa-cho, Hokuto-shi, Yamanashi, 408-0044, Japan.
| | - Yoshihisa Miwa
- Nihon Bioresearch Inc., 6-104 Majima, Fukuju-cho, Hashima-shi, Gifu, 501-6251, Japan.
| | - Takahiro Ishii
- BoZo Research Center Inc., 1284 Kamado, Gotennba-shi, Shizuoka, 412-0039, Japan.
| | - Takahiko Nagase
- Nihon Bioresearch Inc., 6-104 Majima, Fukuju-cho, Hashima-shi, Gifu, 501-6251, Japan.
| | - Yoshihiro Katsumata
- BoZo Research Center Inc., 1284 Kamado, Gotennba-shi, Shizuoka, 412-0039, Japan.
| | - Akihiko Hirose
- Division of Risk Assessment, Center for Biological Safety & Research, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan.
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Smart DJ, Helbling FR, McHugh D, Vanscheeuwijck P. Baseline effects of non-flavored e-liquids in the in vitro micronucleus assay. TOXICOLOGY RESEARCH AND APPLICATION 2019. [DOI: 10.1177/2397847319887904] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Electronic nicotine delivery systems (ENDSs; e.g. e-cigarettes) are being developed as potentially reduced-risk alternatives to the continued use of conventional tobacco products. They typically comprise a device that heats an e-liquid to generate inhalable vapor. E-liquids and ENDS-derived vapor have been the focus of toxicological assessment; in particular, their DNA-damaging potential has been investigated with varying outcomes and conclusions. In vitro genetic toxicology assays have formed a part of these assessments. However, they are susceptible to producing misleading or false positive results, especially under extreme conditions. In the present study, we evaluated a series of six neat (non-vaporized) non-flavored e-liquids (NFEL-A to F) in a flow cytometry version of the in vitro micronucleus assay in order to characterize their baseline effects on Chinese hamster ovary cells under hazard identification conditions. The NFELs induced cytotoxicity universally despite differing in propylene glycol (PG), vegetable glycerin (VG), and nicotine content. In addition, significant genotoxic responses were also detected with the PG-predominant e-liquids NFEL-A, D, and F but not with NFEL-B, C, or E, which contained higher proportions of VG. All six NFELs induced extreme cell culture conditions (i.e. increases in pH and osmolality) at the concentrations assessed. They also exhibited nonbiologically relevant effects on the mechanistic endpoints (i.e. cell cycle and phosphorylated histones H2AX and H3). In conclusion, although the PG component of the NFELs drove micronucleus formation in the assay, data on the complementary mechanistic endpoints suggest that this apparent DNA damage is potentially misleading and of negligible biological relevance as a risk for DNA integrity. In future assessments, any adverse changes (such as signatures of micronuclei induction, G2M arrest, and increases in γH2AX) relative to this reference data set might indicate a possible genotoxic hazard and would prompt further investigations for exploring the extent of risk.
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Affiliation(s)
- Daniel J Smart
- Philip Morris International Research and Development, Philip Morris Products S.A., Neuchâtel, Switzerland
| | - Fabian R Helbling
- Philip Morris International Research and Development, Philip Morris Products S.A., Neuchâtel, Switzerland
| | - Damian McHugh
- Philip Morris International Research and Development, Philip Morris Products S.A., Neuchâtel, Switzerland
| | - Patrick Vanscheeuwijck
- Philip Morris International Research and Development, Philip Morris Products S.A., Neuchâtel, Switzerland
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White PA, Luijten M, Mishima M, Cox JA, Hanna JN, Maertens RM, Zwart EP. In vitro mammalian cell mutation assays based on transgenic reporters: A report of the International Workshop on Genotoxicity Testing (IWGT). MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2019; 847:403039. [DOI: 10.1016/j.mrgentox.2019.04.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 03/26/2019] [Accepted: 04/06/2019] [Indexed: 02/07/2023]
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7
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Hasselgren C, Ahlberg E, Akahori Y, Amberg A, Anger LT, Atienzar F, Auerbach S, Beilke L, Bellion P, Benigni R, Bercu J, Booth ED, Bower D, Brigo A, Cammerer Z, Cronin MTD, Crooks I, Cross KP, Custer L, Dobo K, Doktorova T, Faulkner D, Ford KA, Fortin MC, Frericks M, Gad-McDonald SE, Gellatly N, Gerets H, Gervais V, Glowienke S, Van Gompel J, Harvey JS, Hillegass J, Honma M, Hsieh JH, Hsu CW, Barton-Maclaren TS, Johnson C, Jolly R, Jones D, Kemper R, Kenyon MO, Kruhlak NL, Kulkarni SA, Kümmerer K, Leavitt P, Masten S, Miller S, Moudgal C, Muster W, Paulino A, Lo Piparo E, Powley M, Quigley DP, Reddy MV, Richarz AN, Schilter B, Snyder RD, Stavitskaya L, Stidl R, Szabo DT, Teasdale A, Tice RR, Trejo-Martin A, Vuorinen A, Wall BA, Watts P, White AT, Wichard J, Witt KL, Woolley A, Woolley D, Zwickl C, Myatt GJ. Genetic toxicology in silico protocol. Regul Toxicol Pharmacol 2019; 107:104403. [PMID: 31195068 PMCID: PMC7485926 DOI: 10.1016/j.yrtph.2019.104403] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 05/20/2019] [Accepted: 06/05/2019] [Indexed: 01/23/2023]
Abstract
In silico toxicology (IST) approaches to rapidly assess chemical hazard, and usage of such methods is increasing in all applications but especially for regulatory submissions, such as for assessing chemicals under REACH as well as the ICH M7 guideline for drug impurities. There are a number of obstacles to performing an IST assessment, including uncertainty in how such an assessment and associated expert review should be performed or what is fit for purpose, as well as a lack of confidence that the results will be accepted by colleagues, collaborators and regulatory authorities. To address this, a project to develop a series of IST protocols for different hazard endpoints has been initiated and this paper describes the genetic toxicity in silico (GIST) protocol. The protocol outlines a hazard assessment framework including key effects/mechanisms and their relationships to endpoints such as gene mutation and clastogenicity. IST models and data are reviewed that support the assessment of these effects/mechanisms along with defined approaches for combining the information and evaluating the confidence in the assessment. This protocol has been developed through a consortium of toxicologists, computational scientists, and regulatory scientists across several industries to support the implementation and acceptance of in silico approaches.
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Affiliation(s)
| | - Ernst Ahlberg
- Predictive Compound ADME & Safety, Drug Safety & Metabolism, AstraZeneca IMED Biotech Unit, Mölndal, Sweden
| | - Yumi Akahori
- Chemicals Evaluation and Research Institute, 1-4-25 Kouraku, Bunkyo-ku, Tokyo, 112-0004, Japan
| | - Alexander Amberg
- Sanofi, R&D Preclinical Safety Frankfurt, Industriepark Hoechst, D-65926, Frankfurt am Main, Germany
| | - Lennart T Anger
- Sanofi, R&D Preclinical Safety Frankfurt, Industriepark Hoechst, D-65926, Frankfurt am Main, Germany
| | - Franck Atienzar
- UCB BioPharma SPRL, Chemin du Foriest, B-1420 Braine-l'Alleud, Belgium
| | - Scott Auerbach
- The National Institute of Environmental Health Sciences, Division of the National Toxicology Program, Research Triangle Park, NC, 27709, USA
| | - Lisa Beilke
- Toxicology Solutions Inc., San Diego, CA, USA
| | | | | | - Joel Bercu
- Gilead Sciences, 333 Lakeside Drive, Foster City, CA, USA
| | - Ewan D Booth
- Syngenta, Product Safety Department, Jealott's Hill International Research Centre, Bracknell, Berkshire, RG42 6EY, UK
| | - Dave Bower
- Leadscope, Inc, 1393 Dublin Rd, Columbus, OH, 43215, USA
| | - Alessandro Brigo
- Roche Pharmaceutical Research & Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070, Basel, Switzerland
| | - Zoryana Cammerer
- Janssen Research & Development, 1400 McKean Road, Spring House, PA, 19477, USA
| | - Mark T D Cronin
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, L3 3AF, UK
| | - Ian Crooks
- British American Tobacco, Research and Development, Regents Park Road, Southampton, Hampshire, SO15 8TL, UK
| | - Kevin P Cross
- Leadscope, Inc, 1393 Dublin Rd, Columbus, OH, 43215, USA
| | - Laura Custer
- Bristol-Myers Squibb, Drug Safety Evaluation, 1 Squibb Dr, New Brunswick, NJ, 08903, USA
| | - Krista Dobo
- Pfizer Global Research & Development, 558 Eastern Point Road, Groton, CT, 06340, USA
| | - Tatyana Doktorova
- Douglas Connect GmbH, Technology Park Basel, Hochbergerstrasse 60C, CH-4057, Basel / Basel-Stadt, Switzerland
| | - David Faulkner
- Lawrence Berkeley National Laboratory, One Cyclotron Road, MS 70A-1161A, Berkeley, CA, 947020, USA
| | - Kevin A Ford
- Global Blood Therapeutics, 171 Oyster Point Boulevard, South San Francisco, CA, 94080, USA
| | - Marie C Fortin
- Jazz Pharmaceuticals, Inc., 200 Princeton South Corporate Center, Suite 180, Ewing, NJ, 08628, USA; Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy, Rutgers University, 170 Frelinghuysen Rd, Piscataway, NJ, 08855, USA
| | | | | | - Nichola Gellatly
- National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs), Gibbs Building, 215 Euston Road, London, NW1 2BE, UK
| | - Helga Gerets
- UCB BioPharma SPRL, Chemin du Foriest, B-1420, Braine-l'Alleud, Belgium
| | | | - Susanne Glowienke
- Novartis Pharma AG, Pre-Clinical Safety, Werk Klybeck, CH, 4057, Basel, Switzerland
| | - Jacky Van Gompel
- Janssen Pharmaceutical Companies of Johnson & Johnson, 2340, Beerse, Belgium
| | - James S Harvey
- GlaxoSmithKline Pre-Clinical Development, Park Road, Ware, Hertfordshire, SG12 0DP, UK
| | - Jedd Hillegass
- Bristol-Myers Squibb, Drug Safety Evaluation, 1 Squibb Dr, New Brunswick, NJ, 08903, USA
| | - Masamitsu Honma
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, Kanagawa, 210-9501, Japan
| | - Jui-Hua Hsieh
- Kelly Government Solutions, Research Triangle Park, NC, 27709, USA
| | - Chia-Wen Hsu
- FDA Center for Drug Evaluation and Research, Silver Spring, MD, USA
| | | | | | - Robert Jolly
- Toxicology Division, Eli Lilly and Company, Indianapolis, IN, USA
| | - David Jones
- Medicines and Healthcare Products Regulatory Agency, 10 South Colonnade, Canary Wharf, London, E14 4PU, UK
| | - Ray Kemper
- Vertex Pharmaceuticals Inc., Predictive and Investigative Safety Assessment, 50 Northern Ave, Boston, MA, USA
| | - Michelle O Kenyon
- Pfizer Global Research & Development, 558 Eastern Point Road, Groton, CT, 06340, USA
| | - Naomi L Kruhlak
- FDA Center for Drug Evaluation and Research, Silver Spring, MD, USA
| | - Sunil A Kulkarni
- Existing Substances Risk Assessment Bureau, Health Canada, Ottawa, ON, K1A 0K9, Canada
| | - Klaus Kümmerer
- Institute for Sustainable and Environmental Chemistry, Leuphana University Lüneburg, Scharnhorststraße 1/C13.311b, 21335, Lüneburg, Germany
| | - Penny Leavitt
- Bristol-Myers Squibb, Drug Safety Evaluation, 1 Squibb Dr, New Brunswick, NJ, 08903, USA
| | - Scott Masten
- The National Institute of Environmental Health Sciences, Division of the National Toxicology Program, Research Triangle Park, NC, 27709, USA
| | - Scott Miller
- Leadscope, Inc, 1393 Dublin Rd, Columbus, OH, 43215, USA
| | | | - Wolfgang Muster
- Roche Pharmaceutical Research & Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070, Basel, Switzerland
| | | | | | - Mark Powley
- Merck Research Laboratories, West Point, PA, 19486, USA
| | | | | | | | | | - Ronald D Snyder
- RDS Consulting Services, 2936 Wooded Vista Ct, Mason, OH, 45040, USA
| | | | | | | | | | | | | | | | - Brian A Wall
- Colgate-Palmolive Company, Piscataway, NJ, 08854, USA
| | - Pete Watts
- Bibra, Cantium House, Railway Approach, Wallington, Surrey, SM6 0DZ, UK
| | - Angela T White
- GlaxoSmithKline Pre-Clinical Development, Park Road, Ware, Hertfordshire, SG12 0DP, UK
| | - Joerg Wichard
- Bayer AG, Pharmaceuticals Division, Investigational Toxicology, Muellerstr. 178, D-13353, Berlin, Germany
| | - Kristine L Witt
- The National Institute of Environmental Health Sciences, Division of the National Toxicology Program, Research Triangle Park, NC, 27709, USA
| | - Adam Woolley
- ForthTox Limited, PO Box 13550, Linlithgow, EH49 7YU, UK
| | - David Woolley
- ForthTox Limited, PO Box 13550, Linlithgow, EH49 7YU, UK
| | - Craig Zwickl
- Transendix LLC, 1407 Moores Manor, Indianapolis, IN, 46229, USA
| | - Glenn J Myatt
- Leadscope, Inc, 1393 Dublin Rd, Columbus, OH, 43215, USA
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Mosesso P, Cinelli S. In Vitro Cytogenetic Assays: Chromosomal Aberrations and Micronucleus Tests. Methods Mol Biol 2019; 2031:79-104. [PMID: 31473955 DOI: 10.1007/978-1-4939-9646-9_4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Chromosome damage is a very important indicator of genetic damage relevant to environmental and clinical studies. Detailed descriptions of the protocols used for detection of chromosomal aberrations induced by genotoxic agents in vitro both in the presence or absence of rat liver-derived metabolizing systems are given in this chapter. Structural chromosomal aberrations that can be observed and quantified at metaphases are described here. For the detection of chromosomal damage (fragments or whole chromosome) in interphase, the micronucleus test can be used, and a description of this test is also presented. Criteria for determining a positive result using appropriate statistical methods are described.
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Affiliation(s)
- Pasquale Mosesso
- Dipartimento di Scienze Ecologiche e Biologiche, Università degli Studi della Tuscia, Largo dell'Università, Viterbo, Italy.
| | - Serena Cinelli
- Research Toxicology Centre S.p.A., Pomezia (Roma), Italy
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Emerce E, Çetin Ö. Genotoxicity assessment of perfluoroalkyl substances on human sperm. Toxicol Ind Health 2018; 34:884-890. [PMID: 30326792 DOI: 10.1177/0748233718799191] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are synthetic chemicals that have been used in industry and consumer products. Because the presence of PFAS has been identified in humans and the environment in the last decade, human exposure to PFAS is a current public health concern. It has been shown that some PFAS lead to adverse health effects in the male reproductive system. However, there is no information about probable genotoxic effects of these chemicals on sperm cells. This study aimed to investigate the possible genotoxic damage on human sperm cells exposed to certain major PFAS compounds that were selected considering their extensive usage, high persistence in the environment, and high bioaccumulation in humans. These PFAS are perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorohexanoic acid (PFHxA). The alkaline comet assay was used to detect the DNA damage to sperm. Sperm cells were treated with 0.1-1 mM of each PFAS at 32°C for 1 h to obtain optimal survival. As a result of the experiments, it was discovered that the exposure to PFOS, PFOA, PFNA, and PFHxA did not cause significant levels of cytotoxicity and did not cause damage to sperm DNA under these conditions. The results suggest that the exposure to these PFAS did not interfere with sperm DNA. Indirect toxicity mechanisms should be taken into account to assess the association between the PFAS exposure and male reproductive toxicity.
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Affiliation(s)
- Esra Emerce
- Department of Toxicology, Faculty of Pharmacy, Gazi University, Ankara, Turkey
| | - Özge Çetin
- Department of Toxicology, Faculty of Pharmacy, Gazi University, Ankara, Turkey
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Honda H, Fujita Y, Kasamatsu T, Fuchs A, Fautz R, Morita O. Necessity for retrospective evaluation of past-positive chemicals in in vitro chromosomal aberration tests using recommended cytotoxicity indices. Genes Environ 2018; 40:2. [PMID: 29339977 PMCID: PMC5761126 DOI: 10.1186/s41021-017-0091-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 12/07/2017] [Indexed: 11/10/2022] Open
Abstract
We have demonstrated that retrospective evaluation of existing data of in vitro chromosomal aberration test using the new cytotoxicity indices RICC (relative increase in cell count) or RPD (relative population doubling) reduces the false-positive rate. We have constructed an algorithm to predict the likelihood that past-positive results would differ when retested accordingly. Here, we emphasize the importance of reviewing existing in vitro chromosomal aberration test results. The present Letter not only supports the rediscovery of potentially useful chemicals excluded from further development as a result of misclassification due to in vitro false-positive results, but also contributes to the development of a precise Quantitative Structure-Activity Relationship (QSAR) model by providing an appropriate training data-set. Furthermore, re-evaluation is expected to provide novel insights into underlying mechanisms and/or key structures involved in the development of chromosomal aberrations.
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Affiliation(s)
- Hiroshi Honda
- R&D Safety Science Research, Kao Corporation, 2606 Akabane, Ichikai-Machi, Haga-Gun, Tochigi, 321-3497 Japan
| | - Yurika Fujita
- R&D Safety Science Research, Kao Corporation, 2606 Akabane, Ichikai-Machi, Haga-Gun, Tochigi, 321-3497 Japan
| | - Toshio Kasamatsu
- R&D Safety Science Research, Kao Corporation, 2606 Akabane, Ichikai-Machi, Haga-Gun, Tochigi, 321-3497 Japan
| | - Anne Fuchs
- Kao Europe Research Laboratories, Kao Germany GmbH, Darmstadt, 64297 Germany
| | - Rolf Fautz
- Kao Europe Research Laboratories, Kao Germany GmbH, Darmstadt, 64297 Germany
| | - Osamu Morita
- R&D Safety Science Research, Kao Corporation, 2606 Akabane, Ichikai-Machi, Haga-Gun, Tochigi, 321-3497 Japan
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11
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Wilde S, Dambowsky M, Hempt C, Sutter A, Queisser N. Classification of in vitro genotoxicants using a novel multiplexed biomarker assay compared to the flow cytometric micronucleus test. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2017; 58:662-677. [PMID: 28940655 DOI: 10.1002/em.22130] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 07/26/2017] [Accepted: 07/28/2017] [Indexed: 06/07/2023]
Abstract
Regulatory in vitro genotoxicity testing exhibits shortcomings in specificity and mode of action (MoA) information. Thus, the aim of this work was to evaluate the performance of the novel MultiFlow® assay composed of mechanistic biomarkers quantified in TK6 cells after treatment (4 and 24 hr): γH2AX (DNA double strand breaks), phosphorylated H3 (mitotic cells), translocated p53 (genotoxicity), and cleaved PARP1 (apoptosis). A reference dataset of 31 compounds with well-established MoA was studied using the MicroFlow® micronucleus assay. A positive call was raised following the earlier published criteria from Litron Laboratories. In the light of our data, these evaluation criteria should probably be adjusted since only 8/11 (73%) nongenotoxicants and 18/20 (90%) genotoxicants were correctly identified. Moreover, there is a need for new in vitro tools to delineate the predominant MoA as in the MicroFlow® assay only 5/9 (56%) aneugens and 4/11 (36%) clastogens were correctly classified. In contrast, the MultiFlow® assay provides more in-depth information about the MoA and therefore reliably discriminates clastogens, aneugens, and nongenotoxicants. By using a lab-specific, practical threshold for the aforementioned biomarkers, 10/11 (91%) nongenotoxicants and 19/20 genotoxicants (95%), 9/11 (82%) clastogens, and 8/9 (89%) aneugens were correctly categorized, suggesting a clear improvement over the MicroFlow® . Furthermore, the MultiFlow markers were benchmarked against established methods to assess the validity of the data. Altogether, these findings demonstrated good agreement between the MultiFlow® assay and the benchmarking methods. Finally, p21 may improve class discrimination given the correct identification of 4/4 (100%) aneugens and 2/5 (40%) clastogens. Environ. Mol. Mutagen. 58:662-677, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Sabrina Wilde
- Investigational Toxicology, Bayer AG, Berlin, Germany
| | | | - Claudia Hempt
- Investigational Toxicology, Bayer AG, Berlin, Germany
| | | | - Nina Queisser
- Investigational Toxicology, Bayer AG, Berlin, Germany
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Maertens RM, Long AS, White PA. Performance of the in vitro transgene mutation assay in MutaMouse FE1 cells: Evaluation of nine misleading ("False") positive chemicals. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2017; 58:582-591. [PMID: 28843037 DOI: 10.1002/em.22125] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 07/20/2017] [Accepted: 07/20/2017] [Indexed: 06/07/2023]
Abstract
The screening of chemicals for the protection of human health and the environment requires the assessment of genetic toxicity. However, existing, internationally-accepted in vitro mammalian genotoxicity tests have been criticized for their low specificity (i.e. high frequency of "false" or "misleading" positive results for compounds that are negative in vivo). An in vitro transgene mutation assay has been established that uses a metabolically competent cell line derived from MutaMouse lung (i.e. FE1 cells). Mutation scoring employs the well-characterized lacZ positive selection system, and the assay is proposed as an alternative in vitro assessment tool. In this study, the performance of the FE1 cell assay was evaluated by examining responses to nine non-DNA-reactive chemicals that previously elicited misleading positive results in other mammalian cell genotoxicity assays. FE1 cells were exposed to concentrations up to approximately 10 mM and/or concentrations that yielded approximately 80-90% cytotoxicity (as measured by relative increase in cell count). The assay demonstrated excellent specificity; exposures to the chemicals examined did not yield any positive responses even when tested in the presence of an exogenous metabolic activation system (i.e. S9) or with an extended sampling time. These results indicate that the FE1 cell mutagenicity assay is an effective and practical alternative to traditional mammalian cell gene mutation assays. The development and validation of effective in vitro tools such as the MutaMouse FE1 cell assay will contribute to international efforts to reduce, refine, and replace experimental animals for toxicity assessment. Environ. Mol. Mutagen. 58:582-591, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Rebecca M Maertens
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
| | - Alexandra S Long
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
| | - Paul A White
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
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Galloway SM. International regulatory requirements for genotoxicity testing for pharmaceuticals used in human medicine, and their impurities and metabolites. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2017; 58:296-324. [PMID: 28299826 DOI: 10.1002/em.22077] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 02/05/2017] [Indexed: 06/06/2023]
Abstract
The process of developing international (ICH) guidelines is described, and the main guidelines reviewed are the ICH S2(R1) guideline that includes the genotoxicity test battery for human pharmaceuticals, and the ICH M7 guideline for assessing and limiting potentially mutagenic impurities and degradation products in drugs. Key aspects of the guidelines are reviewed in the context of drug development, for example the incorporation of genotoxicity assessment into non-clinical toxicity studies, and ways to develop and assess weight of evidence. In both guidelines, the existence of "thresholds" or non-linear dose responses for genotoxicity plays a part in the strategies. Differences in ICH S2(R1) protocol recommendations from OECD guidelines are highlighted and rationales explained. The use of genotoxicity data during clinical development and in assessment of carcinogenic potential is also described. There are no international guidelines on assessment of potentially genotoxic metabolites, but some approaches to safety assessment are discussed for these. Environ. Mol. Mutagen. 58:296-324, 2017. © 2017 Wiley Periodicals, Inc.
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Takeshita K, Ogawa HI, Maeda T. Structural chromosome aberrations cause swelling of the nucleus. Genes Environ 2016; 38:22. [PMID: 27733886 PMCID: PMC5045629 DOI: 10.1186/s41021-016-0047-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 05/27/2016] [Indexed: 11/24/2022] Open
Abstract
Background Carcinogens are known to cause swelling of the mammalian cell nucleus. However, the mechanism of the swelling and its toxicological significance have not been fully elucidated. Since nuclear swelling (NS hereafter) has been frequently observed in chromosomal aberration (CA hereafter) tests (in vitro), the relationship between NS and CAs was investigated in this study. Results In a short-term CA test using the fibroblast CHL cell line, the appearance of NS increased in a dose-dependent manner after exposure to six types of clastogens (mitomycin C, methyl methane sulfonate, 1-methyl-3-nitro-1-nitrosoguanidine, benzo[a]pyrene, cyclophosphamide monohydrate, and 9,10-dimethyl-2-benzanthracene), and a strong correlation was found between NS (%) and CAs (%) at each dosage. Therefore, we hypothesized that clastogens cause NS in cultured mammalian cells, since the mouse lymphoma L5178Y cell line is known to have a similar sensitivity to clastogens. Thus, we measured NS for 14 compounds (clastogens) that are known to induce structural CAs, 4 aneugens, and 12 non-mutagenes. Almost all clastogens caused NS of more than 5 %, which increased in a dose-dependent manner. Among the aneugens, colchicine, and diethylstilbestrol caused the same level of NS % as the clastogens, while carbendazim and trichlorfon caused a similar level of NS % as the clastogens only at higher levels of cytotoxicity. Almost all the non-mutagens caused less than 5 % NS. Conclusions These results strongly suggest that NS is mainly caused by structural aberrations in the nucleus during interphase of the cell cycle.
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Affiliation(s)
- Kenji Takeshita
- Department of Biological Functions Engineering, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu-ku, Fukuoka, 808-0196 Japan ; UBE Scientific Analysis Laboratory, Inc, 1978-5 Kogushi, Ube, Yamaguchi 755-8633 Japan
| | - Hiroaki I Ogawa
- Department of Biological Functions Engineering, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu-ku, Fukuoka, 808-0196 Japan
| | - Toshinari Maeda
- Department of Biological Functions Engineering, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu-ku, Fukuoka, 808-0196 Japan
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Lorge E, Moore MM, Clements J, O'Donovan M, Fellows MD, Honma M, Kohara A, Galloway S, Armstrong MJ, Thybaud V, Gollapudi B, Aardema MJ, Tanir JY. Standardized cell sources and recommendations for good cell culture practices in genotoxicity testing. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2016; 809:1-15. [PMID: 27692294 DOI: 10.1016/j.mrgentox.2016.08.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 07/29/2016] [Accepted: 08/02/2016] [Indexed: 11/16/2022]
Abstract
Good cell culture practice and characterization of the cell lines used are of critical importance in in vitro genotoxicity testing. The objective of this initiative was to make continuously available stocks of the characterized isolates of the most frequently used mammalian cell lines in genotoxicity testing anywhere in the world ('IVGT' cell lines). This project was organized under the auspices of the International Life Sciences Institute (ILSI) Health and Environmental Sciences Institute (HESI) Project Committee on the Relevance and Follow-up of Positive Results in In Vitro Genetic Toxicity (IVGT) Testing. First, cell isolates were identified that are as close as possible to the isolate described in the initial publications reporting their use in genotoxicity testing. The depositors of these cell lines managed their characterization and their expansion for preparing continuously available stocks of these cells that are stored at the European Collection of Cell Cultures (ECACC, UK) and the Japanese Collection of Research Bioresources (JCRB, Japan). This publication describes how the four 'IVGT' cell lines, i.e. L5178Y TK+/- 3.7.2C, TK6, CHO-WBL and CHL/IU, were prepared for deposit at the ECACC and JCRB cell banks. Recommendations for handling these cell lines and monitoring their characteristics are also described. The growth characteristics of these cell lines (growth rates and cell cycles), their identity (karyotypes and genetic status) and ranges of background frequencies of select endpoints are also reported to help in the routine practice of genotoxicity testing using these cell lines.
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Affiliation(s)
- E Lorge
- Servier Group, 45520, Gidy, France
| | - M M Moore
- Ramboll Environ, Little Rock, AR, 72201, USA
| | - J Clements
- Covance Laboratories Ltd, Harrogate, HG3 1PY, UK
| | - M O'Donovan
- O'Donovan GT Consulting Ltd., Epperstone, Nottingham, NG14 6AG, UK
| | - M D Fellows
- AstraZeneca, Drug Safety and Metabolism, Cambridge, CB4 0WG, UK
| | - M Honma
- National Institute of Health Sciences, Tokyo, Japan
| | - A Kohara
- JCRB Cell Bank, National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan
| | - S Galloway
- Merck Research Laboratories, W 45-316, West Point, PA 19486, USA
| | - M J Armstrong
- Merck Research Laboratories, W 45-316, West Point, PA 19486, USA
| | - V Thybaud
- Sanofi, 94400, Vitry sur Seine, France
| | - B Gollapudi
- Exponent, Inc., 1910 St. Andrews St., Midland, MI 48640, USA
| | - M J Aardema
- Marilyn Aardema Consulting LLC, Fairfield, OH 45014, USA
| | - J Y Tanir
- ILSI Health and Environmental Sciences Institute, Washington, DC 20005, USA.
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Luijten M, Olthof ED, Hakkert BC, Rorije E, van der Laan JW, Woutersen RA, van Benthem J. An integrative test strategy for cancer hazard identification. Crit Rev Toxicol 2016; 46:615-39. [PMID: 27142259 DOI: 10.3109/10408444.2016.1171294] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Assessment of genotoxic and carcinogenic potential is considered one of the basic requirements when evaluating possible human health risks associated with exposure to chemicals. Test strategies currently in place focus primarily on identifying genotoxic potential due to the strong association between the accumulation of genetic damage and cancer. Using genotoxicity assays to predict carcinogenic potential has the significant drawback that risks from non-genotoxic carcinogens remain largely undetected unless carcinogenicity studies are performed. Furthermore, test systems already developed to reduce animal use are not easily accepted and implemented by either industries or regulators. This manuscript reviews the test methods for cancer hazard identification that have been adopted by the regulatory authorities, and discusses the most promising alternative methods that have been developed to date. Based on these findings, a generally applicable tiered test strategy is proposed that can be considered capable of detecting both genotoxic as well as non-genotoxic carcinogens and will improve understanding of the underlying mode of action. Finally, strengths and weaknesses of this new integrative test strategy for cancer hazard identification are presented.
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Affiliation(s)
- Mirjam Luijten
- a Centre for Health Protection, National Institute for Public Health and the Environment (RIVM) , Bilthoven , the Netherlands
| | - Evelyn D Olthof
- a Centre for Health Protection, National Institute for Public Health and the Environment (RIVM) , Bilthoven , the Netherlands
| | - Betty C Hakkert
- b Centre for Safety of Substances and Products, National Institute for Public Health and the Environment (RIVM) , Bilthoven , the Netherlands
| | - Emiel Rorije
- b Centre for Safety of Substances and Products, National Institute for Public Health and the Environment (RIVM) , Bilthoven , the Netherlands
| | | | - Ruud A Woutersen
- d Netherlands Organization for Applied Scientific Research (TNO) , Zeist , the Netherlands
| | - Jan van Benthem
- a Centre for Health Protection, National Institute for Public Health and the Environment (RIVM) , Bilthoven , the Netherlands
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17
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Fujita Y, Morita T, Matsumura S, Kawamoto T, Ito Y, Nishiyama N, Honda H. Comprehensive retrospective evaluation of existing in vitro chromosomal aberration test data by cytotoxicity index transformation. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2016; 802:38-49. [DOI: 10.1016/j.mrgentox.2016.03.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 03/21/2016] [Accepted: 03/21/2016] [Indexed: 01/28/2023]
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Beken S, Kasper P, van der Laan JW. Regulatory Acceptance of Alternative Methods in the Development and Approval of Pharmaceuticals. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 856:33-64. [DOI: 10.1007/978-3-319-33826-2_3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Ji Z, McHale CM, Bersonda J, Tung J, Smith MT, Zhang L. Induction of centrosome amplification by formaldehyde, but not hydroquinone, in human lymphoblastoid TK6 cells. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2015; 56:535-44. [PMID: 25821186 PMCID: PMC6529207 DOI: 10.1002/em.21947] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 02/20/2015] [Indexed: 05/08/2023]
Abstract
Benzene and formaldehyde (FA) are important industrial chemicals and environmental pollutants that cause leukemia by inducing DNA damage and chromosome aberrations in hematopoietic stem cells (HSC), the target cells for leukemia. Our previous studies showed that workers exposed to benzene and FA exhibit increased levels of aneuploidy in their blood cells. As centrosome amplification is a common phenomenon in human cancers, including leukemia, and is associated with aneuploidy in carcinogenesis, we hypothesized that benzene and FA would induce centrosome amplification in vitro. We treated human lymphoblastoid TK6 cells with a range of concentrations of hydroquinone (HQ, a benzene metabolite) or FA for 24 h, allowed the cells to recover in fresh medium for 24 h, and examined centrosome amplification; chromosomal gain, loss, and breakage; and cytotoxicity. We included melphalan and etoposide, chemotherapeutic drugs that cause therapy-related acute myeloid leukemia and that have been shown to induce centrosome amplification as well as chromosomal aneuploidy and breakage, as positive controls. Melphalan and etoposide induced centrosome amplification and chromosome gain and breakage in a dose-dependent manner, at cytotoxic concentrations. HQ, though cytotoxic, did not induce centrosome amplification or any chromosomal aberration. FA-induced centrosome amplification and cytotoxicity, but did not induce chromosomal aberrations. Our data suggest, for the first time, that centrosome amplification is a potential mechanism underlying FA-induced leukemogenesis, but not benzene-induced leukemogenesis, as mediated through HQ. Future studies are needed to delineate the mechanisms of centrosome amplification and its association with DNA damage, chromosomal aneuploidy and carcinogenesis, following exposure to FA.
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Affiliation(s)
- Zhiying Ji
- Division of Environmental Health Sciences, Genes and Environment Laboratory, School of Public Health, University of California, Berkeley, California
| | - Cliona M. McHale
- Division of Environmental Health Sciences, Genes and Environment Laboratory, School of Public Health, University of California, Berkeley, California
| | - Jessica Bersonda
- Division of Environmental Health Sciences, Genes and Environment Laboratory, School of Public Health, University of California, Berkeley, California
| | - Judy Tung
- Division of Environmental Health Sciences, Genes and Environment Laboratory, School of Public Health, University of California, Berkeley, California
| | - Martyn T. Smith
- Division of Environmental Health Sciences, Genes and Environment Laboratory, School of Public Health, University of California, Berkeley, California
| | - Luoping Zhang
- Division of Environmental Health Sciences, Genes and Environment Laboratory, School of Public Health, University of California, Berkeley, California
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van der Leede BJ, Doherty A, Guérard M, Howe J, O’Donovan M, Plappert-Helbig U, Thybaud V. Performance and data interpretation of the in vivo comet assay in pharmaceutical industry: EFPIA survey results. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2014; 775-776:81-8. [DOI: 10.1016/j.mrgentox.2014.09.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 09/23/2014] [Indexed: 11/27/2022]
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21
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Bryce SM, Bemis JC, Mereness JA, Spellman RA, Moss J, Dickinson D, Schuler MJ, Dertinger SD. Interpreting in vitro micronucleus positive results: simple biomarker matrix discriminates clastogens, aneugens, and misleading positive agents. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2014; 55:542-555. [PMID: 24756928 DOI: 10.1002/em.21868] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 03/31/2014] [Accepted: 04/01/2014] [Indexed: 06/03/2023]
Abstract
The specificity of in vitro mammalian cell genotoxicity assays is low, as they yield a high incidence of positive results that are not observed in animal genotoxicity and carcinogenicity tests, that is, "misleading" or "irrelevant" positives. We set out to develop a rapid and effective follow-up testing strategy that would predict whether apparent in vitro micronucleus-inducing effects are due to a clastogenic, aneugenic, or secondary irrelevant mode(s) of action. Priority was given to biomarkers that could be multiplexed onto flow cytometric acquisition of micronucleus frequencies, or that could be accomplished in parallel using a homogeneous-type assay. A training set of 30 chemicals comprised of clastogens, aneugens, and misleading positive chemicals was studied. These experiments were conducted with human TK6 cells over a range of closely spaced concentrations in a continuous exposure design. In addition to micronucleus frequency, the following endpoints were investigated, most often at time of harvest: cleaved Parp-positive chromatin, cleaved caspase 3-positive chromatin, ethidium monoazide bromide-positive chromatin, polyploid nuclei, phospho-histone H3-positive (metaphase) cells, tetramethylrhodamine ethyl ester-negative cells, cellular ATP levels, cell cycle perturbation, and shift in γ-H2AX fluorescence relative to solvent control. Logistic regression was used to identify endpoints that effectively predict chemicals' a priori classification. Cross validation using a leave-one-out approach indicated that a promising base model includes γ-H2AX shift and change in phospho-histone H3-positive events (25/30 correct calls). Improvements were realized when one or two additional endpoints were included (26-30/30 correct calls). These models were further evaluated with a test set of 10 chemicals, and also by evaluating 3 chemicals at a collaborating laboratory. The resulting data support the hypothesis that a matrix of high throughput-compatible biomarkers can effectively delineate two important modes of genotoxic action as well as identify cytotoxicity that can lead to irrelevant positive results.
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22
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Morita T, Miyajima A, Hatano A, Honma M. Effects of lowering the proposed top-concentration limit in an in vitro chromosomal aberration test on assay sensitivity and on the reduction of the number of false positives. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2014; 769:34-49. [DOI: 10.1016/j.mrgentox.2014.04.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Revised: 03/04/2014] [Accepted: 04/05/2014] [Indexed: 10/25/2022]
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23
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Butenhoff JL, Kennedy GL, Jung R, Chang SC. Evaluation of perfluorooctanoate for potential genotoxicity. Toxicol Rep 2014; 1:252-270. [PMID: 28962243 PMCID: PMC5598378 DOI: 10.1016/j.toxrep.2014.05.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 05/03/2014] [Accepted: 05/07/2014] [Indexed: 01/30/2023] Open
Abstract
Perfluorooctanoate (PFOA) is a fully fluorinated eight-carbon fatty acid analog with exceptional stability toward degradation that has been used as an industrial surfactant and has been detected in environmental and biological matrices. Exposures to PFOA in the workplace and in the environment have continuously stimulated investigations into its potential human health hazards. In this article, the results of fifteen unpublished genotoxicity assays conducted with perfluorooctanoate (as either the linear or linear/branched ammonium salt (APFO) or the linear/branched sodium salt) are reported and include: seven mutation assays (three in vitro reverse mutation assays with histidine auxotrophic strains of Salmonella typhimurium, two in vitro reverse mutation assays with the tryptophan auxotrophic Escherichia coli WP2uvr strain, one in vitro mitotic recombination (gene conversion) assay with Saccharomyces cerevisiae D4, and an in vitro Chinese hamster ovary (CHO) HGPRT forward mutation assay); seven studies to assess potential for chromosomal damage (three in vitro CHO chromosomal aberration studies, an in vitro human whole blood lymphocyte chromosomal aberration study, and three in vivo mouse micronucleus assays); and an in vitro C3H 10T1/2 cell transformation assay. Although PFOA has not been demonstrated to be metabolized, all in vitro assays were conducted both in the presence and in the absence of a mammalian hepatic microsomal activation system. These assays were originally described in twelve contract laboratory reports which have been available via the United States Environmental Protection Agency public docket (Administrative Record 226) for over a decade; however, the details of these assays have not been published previously in the open scientific literature. With the exception of limited positive findings at high and cytotoxic concentrations in some assay trials which reflected the likely consequence of cytotoxic disruption of normal cellular processes and not a specific genotoxic effect, the results of the studies presented in this paper and other published results clearly demonstrate the absence of direct mutagenic or genotoxic risk associated with PFOA. This finding is consistent with the physical/chemical characteristics of PFOA and is supported by other published genotoxicity studies.
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Affiliation(s)
| | | | - Reinhard Jung
- Toxicology Consultant, Muellerwies 12, Taunusstein 65232, Germany
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Speit G, Vesely A, Schutz P, Linsenmeyer R, Bausinger J. The low molecular weight DNA diffusion assay as an indicator of cytotoxicity for the in vitro comet assay. Mutagenesis 2014; 29:267-77. [DOI: 10.1093/mutage/geu015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
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25
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van der Linden SC, von Bergh ARM, van Vught-Lussenburg BMA, Jonker LRA, Teunis M, Krul CAM, van der Burg B. Development of a panel of high-throughput reporter-gene assays to detect genotoxicity and oxidative stress. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2013; 760:23-32. [PMID: 24362253 DOI: 10.1016/j.mrgentox.2013.09.009] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 08/13/2013] [Accepted: 09/28/2013] [Indexed: 12/22/2022]
Abstract
The lack of toxicological information on many of the compounds that humans use or are exposed to, intentionally or unintentionally, poses a big problem in risk assessment. To fill this data gap, more emphasis is given to fast in vitro screening tools that can add toxicologically relevant information regarding the mode(s) of action via which compounds can elicit adverse effects, including genotoxic effects. By use of bioassays that can monitor the activation of specific cellular signalling pathways, many compounds can be screened in a high-throughput manner. We have developed two new specific reporter-gene assays that can monitor the effects of compounds on two pathways of interest: the p53 pathway (p53 CALUX) for genotoxicity and the Nrf2 pathway (Nrf2 CALUX) for oxidative stress. To exclude non-specific effects by compounds influencing the luciferase reporter-gene expression non-specifically, a third assay was developed to monitor changes in luciferase expression by compounds in general (Cytotox CALUX). To facilitate interpretation of the data and to avoid artefacts, all three reporter-gene assays used simple and defined reporter genes and a similar cellular basis, the human U2OS cell line. The three cell lines were validated with a range of reference compounds including genotoxic and non-genotoxic agents. The sensitivity (95%) and specificity (85%) of the p53 CALUX was high, showing that the assay is able to identify various types of genotoxic compound, while avoiding the detection of false positives. The Nrf2 CALUX showed specific responses to oxidants only, enabling the identification of compounds that elicit part of their genotoxicity via oxidative stress. All reporter-gene assays can be used in a high-throughput screening format and can be supplemented with other U2OS-based reporter-gene assays that can profile nuclear receptor activity, and several other signalling pathways.
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Affiliation(s)
| | - Anne R M von Bergh
- Innovative Testing in Life Sciences and Chemistry, Research Centre Technology & Innovation, University of Applied Sciences Utrecht, The Netherlands
| | | | | | - Marc Teunis
- Innovative Testing in Life Sciences and Chemistry, Research Centre Technology & Innovation, University of Applied Sciences Utrecht, The Netherlands
| | - Cyrille A M Krul
- Innovative Testing in Life Sciences and Chemistry, Research Centre Technology & Innovation, University of Applied Sciences Utrecht, The Netherlands
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Genotoxicity of pyrroloquinoline quinone (PQQ) disodium salt (BioPQQ™). Regul Toxicol Pharmacol 2013; 67:189-97. [PMID: 23891671 DOI: 10.1016/j.yrtph.2013.07.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 07/11/2013] [Accepted: 07/15/2013] [Indexed: 11/22/2022]
Abstract
The genotoxic potential of pyrroloquinoline quinone (PQQ) disodium salt (BioPQQ™) was evaluated in a battery of genotoxicity tests. The results of the bacterial mutation assay (Ames test) were negative. Weak positive results were obtained in 2 separate in vitro chromosomal aberration test in Chinese hamster lung (CHL) fibroblasts. Upon testing in an in vitro chromosomal aberration test in human peripheral blood lymphocytes, no genotoxic activity of PQQ was noted. In the in vivo micronucleus assay in mice, PQQ at doses up to 2,000 mg/kg body weight demonstrated that no genotoxic effects are expressed in vivo in bone marrow erythrocytes. The weak responses in the in vitro test CHL cells were considered of little relevance under conditions of likely human exposure. PQQ disodium was concluded to have no genotoxic activity in vivo.
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Joint Statement of EFSA and EMA on the presence of residues of phenylbutazone in horse meat. EFSA J 2013. [DOI: 10.2903/j.efsa.2013.3190] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Azqueta A, Arbillaga L, Lopez de Cerain A, Collins A. Enhancing the sensitivity of the comet assay as a genotoxicity test, by combining it with bacterial repair enzyme FPG. Mutagenesis 2013; 28:271-7. [DOI: 10.1093/mutage/get002] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Mosesso P, Cinelli S, Natarajan AT, Palitti F. In vitro cytogenetic assays: chromosomal aberrations and micronucleus tests. Methods Mol Biol 2013; 1044:123-146. [PMID: 23896874 DOI: 10.1007/978-1-62703-529-3_6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Chromosome damage is a very important indicator of genetic damage relevant to environmental and clinical studies. Detailed descriptions of the protocols used for detection of chromosomal aberrations induced by unknown agents in vitro both in the presence or the absence of rat liver-derived metabolizing systems are given. Structural chromosomal aberrations that can be observed and quantified at metaphases are described here. For the detection of chromosomal damage (fragments or whole chromosome) in interphase, the micronucleus test can be used and a description of this test is also presented. Criteria for determining a positive result using appropriate statistical methods are described.
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Affiliation(s)
- Pasquale Mosesso
- Dipartimento di Scienze Ecologiche e Biologiche, Università degli Studi della Tuscia, Largo dell'Università, Viterbo, Italy
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The Evolution, Scientific Reasoning and Use of ICH S2 Guidelines for Genotoxicity Testing of Pharmaceuticals. GLOBAL APPROACH IN SAFETY TESTING 2013. [DOI: 10.1007/978-1-4614-5950-7_6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
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Brookmire L, Chen JJ, Levy DD. Evaluation of the highest concentrations used in the in vitro chromosome aberrations assay. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2013; 54:36-43. [PMID: 23076808 DOI: 10.1002/em.21738] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 08/17/2012] [Accepted: 08/19/2012] [Indexed: 06/01/2023]
Abstract
There is controversy over the highest concentration to which an article should be tested in in vitro mammalian cell assays of genetic toxicity. Until recently, most guidelines specified the use of concentrations of up to 10 mM or 5,000 μg/ml (whichever is lower) when not limited by the toxicity of the test article to the cells used for the test. Several recent publications have called for lowering those limits. We examined concentration/response curves for in vitro chromosome aberrations assays. Data was extracted from two published databases to evaluate the lowest dose at which a positive response was reported. Concentration/response curves were simulated using Monte Carlo procedures on log normal distributions of the data. These curves were then used to predict the loss in assay sensitivity that would be incurred by arbitrarily lowering the highest concentration to which the assay is conducted. The simulations suggest that lowering the current high concentration limit from 10 mM would dramatically impact the sensitivity of the assay. In contrast, lowering the high concentration limit using the μg/ml scale, the most commonly applied scale in regulatory submissions, would not have a similar impact on assay sensitivity until the limit concentration was lowered to more than half of the current 5,000 μg/ml limit. This analysis suggests that the current limits of 10 mM and 5,000 μg/ml are not equivalent to one another and challenges the assumption that lowering the 10 mM limit will not decrease assay sensitivity.
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Affiliation(s)
- Lauren Brookmire
- US Food and Drug Administration Office of Food Additive Safety, Center for Food Safety and Applied Nutrition, College Park, Maryland 20740, USA
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Reduction of misleading (“false”) positive results in mammalian cell genotoxicity assays. II. Importance of accurate toxicity measurement. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2012; 747:104-117. [DOI: 10.1016/j.mrgentox.2012.04.013] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Revised: 02/08/2012] [Accepted: 04/19/2012] [Indexed: 11/21/2022]
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Effect of reducing the top concentration used in the in vitro chromosomal aberration test in CHL cells on the evaluation of industrial chemical genotoxicity. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2012; 741:32-56. [DOI: 10.1016/j.mrgentox.2011.10.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Revised: 09/22/2011] [Accepted: 10/06/2011] [Indexed: 11/23/2022]
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Doktorova TY, Pauwels M, Vinken M, Vanhaecke T, Rogiers V. Opportunities for an alternative integrating testing strategy for carcinogen hazard assessment? Crit Rev Toxicol 2011; 42:91-106. [DOI: 10.3109/10408444.2011.623151] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Kirkland D. Improvements in the reliability ofin vitrogenotoxicity testing. Expert Opin Drug Metab Toxicol 2011; 7:1513-20. [DOI: 10.1517/17425255.2011.627855] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Smart DJ, Ahmedi KP, Harvey JS, Lynch AM. Genotoxicity screening via the γH2AX by flow assay. Mutat Res 2011; 715:25-31. [PMID: 21824484 DOI: 10.1016/j.mrfmmm.2011.07.001] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 06/10/2011] [Accepted: 07/08/2011] [Indexed: 05/31/2023]
Abstract
The measurement of serine139-phosphorylated histone H2AX (γH2AX) provides a biomarker of DNA double-strand breaks (DSBs) and may identify potential genotoxic activity. In order to evaluate a flow cytometry assay for γH2AX detection (hereafter termed the γH2AX by flow assay), 6 prototypical (3 pro- and 3 proximate) genotoxins, i.e. dimethylbenz[a]anthracene (DMBA), 2-acetylaminofluorene (2-AAF), benzo[a]pyrene (B[a]P), methyl methane sulphonate (MMS), methyl nitrosourea (MNU) and 4-nitroquinoline oxide (4NQO), were selected to define assay evaluation criteria. In addition, 3 non-genotoxic cytotoxins (phthalic anhydride, n-butyl chloride and hexachloroethane) were included to investigate the influence of cytotoxicity on assay performance. At similar cytotoxicity levels (relative cell counts; RCC 75-40%) all prototypical genotoxins induced marked concentration-dependent increases in γH2AX compared with the non-genotoxins. As a result, assay evaluation criteria for a positive effect were defined as >1.5-fold γH2AX @ RCC >25%. Twenty five additional chemicals with diverse structures and genotoxic activity were selected to evaluate the γH2AX by flow assay. Results were compared with Ames bacterial and in vitro mammalian genotoxicity tests (mouse lymphoma assay and/or chromosome aberration assay). γH2AX by flow assay results were highly predictive of Ames (sensitivity 100%; specificity 67%; concordance 82%) and in vitro mammalian genotoxicity tests (sensitivity 91%; specificity 89%; concordance 91%) and provide additional evidence that γH2AX is a biomarker of potential genotoxic activity, underpinned mechanistically by the cellular response to DSBs. Discordant findings were predominately attributed to differences in specificity for some mammalian cell genotoxins that are Ames non-mutagens or for "biologically-irrelevant" positives in the mammalian tests. Simple anilines were classified as genotoxic following rat liver S9-mediated bioactivation, however, effects on γH2AX were atypical and limited to a small sub-population of S-phase nuclei. Nevertheless, the γH2AX by flow assay represents a novel genotoxicity assay with the potential to flag both pro- and proximate genotoxins.
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Affiliation(s)
- D J Smart
- Safety Assessment, GlaxoSmithKline R&D, Park Road, Ware, Hertfordshire SG12 0DP, UK.
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Honma M. Cytotoxicity measurement in in vitro chromosome aberration test and micronucleus test. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2011; 724:86-7. [DOI: 10.1016/j.mrgentox.2011.05.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Revised: 05/06/2011] [Accepted: 05/10/2011] [Indexed: 10/18/2022]
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Pfuhler S, Fellows M, van Benthem J, Corvi R, Curren R, Dearfield K, Fowler P, Frötschl R, Elhajouji A, Le Hégarat L, Kasamatsu T, Kojima H, Ouédraogo G, Scott A, Speit G. In vitro genotoxicity test approaches with better predictivity: summary of an IWGT workshop. Mutat Res 2011; 723:101-7. [PMID: 21473931 DOI: 10.1016/j.mrgentox.2011.03.013] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Accepted: 03/28/2011] [Indexed: 02/08/2023]
Abstract
Improving current in vitro genotoxicity tests is an ongoing task for genetic toxicologists. Further, the question on how to deal with positive in vitro results that are demonstrated to not predict genotoxicity or carcinogenicity potential in rodents or humans is a challenge. These two aspects were addressed at the 5th International Workshop on Genotoxicity Testing (IWGT) held in Basel, Switzerland, on August 17-19, 2009. The objectives of the working group (WG) were to make recommendations on the use of cell types or lines, if possible, and to provide evaluations of promising new approaches. Results obtained in rodent cell lines with impaired p53 function (L5178Y, V79, CHL and CHO cells) and human p53-competent cells (peripheral blood lymphocytes, TK6 and HepG2 cells) suggest that a reduction in the percentage of non-relevant positive results for carcinogenicity prediction can be achieved by careful selection of cells used without decreasing the sensitivity of the assays. Therefore, the WG suggested using p53- competent - preferably human - cells in in vitro micronucleus or chromosomal aberration tests. The use of the hepatoma cell line HepaRG for genotoxicity testing was considered promising since these cells possess better phase I and II metabolizing potential compared to cell lines commonly used in this area and may overcome the need for the addition of S9. For dermally applied compounds, the WG agreed that in vitro reconstructed skin models, once validated, will be useful to follow up on positive results from standard in vitro assays as they resemble the properties of human skin (barrier function, metabolism). While the reconstructed skin micronucleus assay has been shown to be further advanced, there was also consensus that the Comet assay should be further evaluated due to its independence from cell proliferation and coverage of a wider spectrum of DNA damage.
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Affiliation(s)
- Stefan Pfuhler
- The Procter and Gamble Co., Miami Valley Innovation Center, 11810 East Miami River Road, Cincinnati, OH 45252, USA.
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