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Geijer ME, Gernaat AM, Moelijker N, Brandsma I, Hendriks G. An Enhanced Metabolization Protocol for In Vitro Genotoxicity Assessment of N-Nitrosamines in Mammalian Cells. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2025; 66:210-220. [PMID: 40152425 PMCID: PMC12087714 DOI: 10.1002/em.70009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2024] [Revised: 03/04/2025] [Accepted: 03/10/2025] [Indexed: 03/29/2025]
Abstract
N-Nitrosamines (NAs) are probable human carcinogens and were detected as impurities in pharmaceuticals, which led to a concern for human health. NAs require metabolic activation before they become mutagenic, and not all NAs are mutagenic since their reactivity is related to their structure. While some NAs are potent mutagens in vivo, in vitro metabolization with exogenous S9 liver extract is generally less efficient. While an enhanced bacterial mutagenicity protocol was recently developed, which uses increased concentrations of S9 liver extracts, there presently is not an improved metabolization protocol suitable for mammalian cell genotoxicity assays. Therefore, we optimized a hamster S9 liver extract-based protocol for in vitro NA metabolization and assessed the genotoxic potential of various NAs using ToxTracker. With this enhanced metabolization protocol (EMP), the genotoxic potency of N-nitrosodimethylamine (NDMA) increased approximately 200-fold compared with the standard S9 liver extract-based exposure protocol in ToxTracker. The EMP was further validated with seven additional mutagenic NAs to which humans are commonly exposed: N-nitrosodiethylamine (NDEA), N-nitrosodiethanolamine (NDELA), N-nitrosodibutylamine (NDBA), N-nitrosofluoxetine (NF), 1-nitrosopyrrolidine (NPYR), N-nitrosomorpholine (NMOR), and 1-cyclopentyl-4-nitrosopiperazine (CPNP), and two non-mutagenic NAs: N-nitrosobupropion (NBuPRO) and N-nitrosoproline (NPRO). Genotoxicity could be confirmed for six NAs using the EMP, demonstrating that mammalian cells and the new approach methodology (NAM) ToxTracker may have potential when investigating NA-related genotoxicity.
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2
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Wu J, Gupta G, Buerki-Thurnherr T, Nowack B, Wick P. Bridging the gap: Innovative human-based in vitro approaches for nanomaterials hazard assessment and their role in safe and sustainable by design, risk assessment, and life cycle assessment. NANOIMPACT 2024; 36:100533. [PMID: 39454678 DOI: 10.1016/j.impact.2024.100533] [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: 07/05/2024] [Revised: 10/22/2024] [Accepted: 10/22/2024] [Indexed: 10/28/2024]
Abstract
The application of nanomaterials in industry and consumer products is growing exponentially, which has pressed the development and use of predictive human in vitro models in pre-clinical analysis to closely extrapolate potential toxic effects in vivo. The conventional cytotoxicity investigation of nanomaterials using cell lines from cancer origin and culturing them two-dimensionally in a monolayer without mimicking the proper pathophysiological microenvironment may affect a precise prediction of in vitro effects at in vivo level. In recent years, complex in vitro models (also belonging to the new approach methodologies, NAMs) have been established in unicellular to multicellular cultures either by using cell lines, primary cells or induced pluripotent stem cells (iPSCs), and reconstituted into relevant biological dimensions mimicking in vivo conditions. These advanced in vitro models retain physiologically reliant exposure scenarios particularly appropriate for oral, dermal, respiratory, and intravenous administration of nanomaterials, which have the potential to improve the in vivo predictability and lead to reliable outcomes. In this perspective, we discuss recent developments and breakthroughs in using advanced human in vitro models for hazard assessment of nanomaterials. We identified fit-for-purpose requirements and remaining challenges for the successful implementation of in vitro data into nanomaterials Safe and Sustainable by Design (SSbD), Risk Assessment (RA), and Life Cycle Assessment (LCA). By addressing the gap between in vitro data generation and the utility of in vitro data for nanomaterial safety assessments, a prerequisite for SSbD approaches, we outlined potential key areas for future development.
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Affiliation(s)
- Jimeng Wu
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Particles-Biology Interactions Laboratory, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland; Empa, Swiss Federal Laboratories for Materials Science and Technology, Technology and Society Laboratory, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Govind Gupta
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Particles-Biology Interactions Laboratory, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Tina Buerki-Thurnherr
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Particles-Biology Interactions Laboratory, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Bernd Nowack
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Technology and Society Laboratory, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Peter Wick
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Particles-Biology Interactions Laboratory, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland.
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3
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Dertinger SD, Briggs E, Hussien Y, Bryce SM, Avlasevich SL, Conrad A, Johnson GE, Williams A, Bemis JC. Visualization strategies to aid interpretation of high-dimensional genotoxicity data. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2024; 65:156-178. [PMID: 38757760 PMCID: PMC11178453 DOI: 10.1002/em.22604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 04/22/2024] [Accepted: 04/23/2024] [Indexed: 05/18/2024]
Abstract
This article describes a range of high-dimensional data visualization strategies that we have explored for their ability to complement machine learning algorithm predictions derived from MultiFlow® assay results. For this exercise, we focused on seven biomarker responses resulting from the exposure of TK6 cells to each of 126 diverse chemicals over a range of concentrations. Obviously, challenges associated with visualizing seven biomarker responses were further complicated whenever there was a desire to represent the entire 126 chemical data set as opposed to results from a single chemical. Scatter plots, spider plots, parallel coordinate plots, hierarchical clustering, principal component analysis, toxicological prioritization index, multidimensional scaling, t-distributed stochastic neighbor embedding, and uniform manifold approximation and projection are each considered in turn. Our report provides a comparative analysis of these techniques. In an era where multiplexed assays and machine learning algorithms are becoming the norm, stakeholders should find some of these visualization strategies useful for efficiently and effectively interpreting their high-dimensional data.
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Affiliation(s)
| | | | - Yusuf Hussien
- Institute of Life Sciences, Swansea University, Swansea, UK
| | | | | | - Adam Conrad
- Litron Laboratories, Rochester, New York, USA
| | | | - Andrew Williams
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, Canada
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4
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Bishop E, Miazzi F, Bozhilova S, East N, Evans R, Smart D, Gaca M, Breheny D, Thorne D. An in vitro toxicological assessment of two electronic cigarettes: E-liquid to aerosolisation. Curr Res Toxicol 2024; 6:100150. [PMID: 38298371 PMCID: PMC10827682 DOI: 10.1016/j.crtox.2024.100150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 01/04/2024] [Accepted: 01/10/2024] [Indexed: 02/02/2024] Open
Abstract
Interest in the toxicological assessment of iterations of e-cigarette devices, e-liquid formulations and flavour use is increasing. Here, we describe a multiple test matrix and in vitro approach to assess the biological impact of differing e-cigarette activation mechanism (button vs. puff-activated) and heating technology (cotton vs. ceramic wick). The e-liquids selected for each device contained the same nicotine concentration and flavourings. We tested both e-liquid and aqueous extract of e-liquid aerosol using a high throughput cytotoxicity and genotoxicity screen. We also conducted whole aerosol assessment both in a reconstituted human airway lung tissue (MucilAir) with associated endpoint assessment (cytotoxicity, TEER, cilia beat frequency and active area) and an Ames whole aerosol assay with up to 900 consecutive undiluted puffs. Following this testing it is shown that the biological impact of these devices is similar, taking into consideration the limitations and capturing efficiencies of the different testing matrices. We have contextualised these responses against previous published reference cigarette data to establish the comparative reduction in response consistent with reduced risk potential of the e-cigarette products tested in this study as compared to conventional cigarettes.
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Affiliation(s)
- E. Bishop
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | - F. Miazzi
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | - S. Bozhilova
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | - N. East
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | - R. Evans
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | - D. Smart
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | - M. Gaca
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | - D. Breheny
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | - D. Thorne
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
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5
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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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6
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Beal MA, Chen G, Dearfield KL, Gi M, Gollapudi B, Heflich RH, Horibata K, Long AS, Lovell DP, Parsons BL, Pfuhler S, Wills J, Zeller A, Johnson G, White PA. Interpretation of in vitro concentration-response data for risk assessment and regulatory decision-making: Report from the 2022 IWGT quantitative analysis expert working group meeting. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2023. [PMID: 38115239 DOI: 10.1002/em.22582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 09/15/2023] [Accepted: 12/16/2023] [Indexed: 12/21/2023]
Abstract
Quantitative risk assessments of chemicals are routinely performed using in vivo data from rodents; however, there is growing recognition that non-animal approaches can be human-relevant alternatives. There is an urgent need to build confidence in non-animal alternatives given the international support to reduce the use of animals in toxicity testing where possible. In order for scientists and risk assessors to prepare for this paradigm shift in toxicity assessment, standardization and consensus on in vitro testing strategies and data interpretation will need to be established. To address this issue, an Expert Working Group (EWG) of the 8th International Workshop on Genotoxicity Testing (IWGT) evaluated the utility of quantitative in vitro genotoxicity concentration-response data for risk assessment. The EWG first evaluated available in vitro methodologies and then examined the variability and maximal response of in vitro tests to estimate biologically relevant values for the critical effect sizes considered adverse or unacceptable. Next, the EWG reviewed the approaches and computational models employed to provide human-relevant dose context to in vitro data. Lastly, the EWG evaluated risk assessment applications for which in vitro data are ready for use and applications where further work is required. The EWG concluded that in vitro genotoxicity concentration-response data can be interpreted in a risk assessment context. However, prior to routine use in regulatory settings, further research will be required to address the remaining uncertainties and limitations.
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Affiliation(s)
- Marc A Beal
- Bureau of Chemical Safety, Health Products and Food Branch, Health Canada, Ottawa, Ontario, Canada
| | - Guangchao Chen
- Centre for Nutrition, Prevention and Health Services, National Institute for Public Health and the Environment (RIVM), Utrecht, the Netherlands
| | - Kerry L Dearfield
- Retired from US Environmental Protection Agency and US Department of Agriculture, Washington, DC, USA
| | - Min Gi
- Department of Environmental Risk Assessment, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | | | - Robert H Heflich
- National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas, USA
| | - Katsuyoshi Horibata
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, Kawasaki, Kanagawa, Japan
| | - Alexandra S Long
- Existing Substances Risk Assessment Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
| | - David P Lovell
- St George's Medical School, University of London, London, UK
| | - Barbara L Parsons
- National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas, USA
| | - Stefan Pfuhler
- Global Product Stewardship - Human Safety, Procter & Gamble, Cincinnati, Ohio, USA
| | - John Wills
- Genetic Toxicology and Photosafety, GSK Research & Development, Stevenage, UK
| | - Andreas Zeller
- Pharmaceutical Sciences, pRED Innovation Center Basel, Hoffmann-La Roche Ltd, Basel, Switzerland
| | - George Johnson
- Swansea University Medical School, Swansea University, Swansea, UK
| | - Paul A White
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
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7
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Kallmyer NE, Agarwal S, Eeg D, Khor R, Roby N, Ramirez AV, Hillier AC, Reuel NF. Lipid-Functionalized Single-Walled Carbon Nanotubes as Probes for Screening Cell Wall Disruptors. ACS APPLIED MATERIALS & INTERFACES 2023; 15:44621-44630. [PMID: 37721709 PMCID: PMC11806933 DOI: 10.1021/acsami.3c06592] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/19/2023]
Abstract
Membrane-active molecules are of great importance to drug delivery and antimicrobials applications. While the ability to prototype new membrane-active molecules has improved greatly with the advent of automated chemistries and rapid biomolecule expression techniques, testing methods are still limited by throughput, cost, and modularity. Existing methods suffer from feasibility constraints of working with pathogenic living cells and by intrinsic limitations of model systems. Herein, we demonstrate an abiotic sensor that uses semiconducting single-walled carbon nanotubes (SWCNTs) as near-infrared fluorescent transducers to report membrane interactions. This sensor is composed of SWCNTs aqueously suspended in lipid, creating a cylindrical, bilayer corona; these SWCNT probes are very sensitive to solvent access (changes in permittivity) and thus report morphological changes to the lipid corona by modulation of fluorescent signals, where binding and disruption are reported as brightening and attenuation, respectively. This mechanism is first demonstrated with chemical and physical membrane-disruptive agents, including ethanol and sodium dodecyl sulfate, and application of electrical pulses. Known cell-penetrating and antimicrobial peptides are then used to demonstrate how the dynamic response of these sensors can be deconvoluted to evaluate different parallel mechanisms of interaction. Last, SWCNTs functionalized in several different bacterial lipopolysaccharides (Pseudomonas aeruginosa, Klebsiella pneumoniae, and Escherichia coli) are used to evaluate a panel of known membrane-disrupting antimicrobials to demonstrate that drug selectivity can be assessed by suspension of SWCNTs with different membrane materials.
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Affiliation(s)
- Nathaniel E. Kallmyer
- Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011, United States of America
| | - Sparsh Agarwal
- Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011, United States of America
| | - Danielle Eeg
- Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011, United States of America
| | - Rachel Khor
- Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011, United States of America
| | - Nathan Roby
- Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011, United States of America
| | - Alma Vela Ramirez
- Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011, United States of America
| | - Andrew C. Hillier
- Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011, United States of America
| | - Nigel F. Reuel
- Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011, United States of America
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8
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Mittal A, Ahuja G. Advancing chemical carcinogenicity prediction modeling: opportunities and challenges. Trends Pharmacol Sci 2023; 44:400-410. [PMID: 37183054 DOI: 10.1016/j.tips.2023.04.002] [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: 03/14/2023] [Revised: 04/11/2023] [Accepted: 04/18/2023] [Indexed: 05/16/2023]
Abstract
Carcinogenicity assessment of any compound is a laborious and expensive exercise with several associated ethical and practical concerns. While artificial intelligence (AI) offers promising solutions, unfortunately, it is contingent on several challenges concerning the inadequacy of available experimentally validated (non)carcinogen datasets and variabilities within bioassays, which contribute to the compromised model training. Existing AI solutions that leverage classical chemistry-driven descriptors do not provide adequate biological interpretability involved in imparting carcinogenicity. This highlights the urgency to devise alternative AI strategies. We propose multiple strategies, including implementing data-driven (integrated databases) and known carcinogen-characteristic-derived features to overcome these apparent shortcomings. In summary, these next-generation approaches will continue facilitating robust chemical carcinogenicity prediction, concomitant with deeper mechanistic insights.
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Affiliation(s)
- Aayushi Mittal
- Department of Computational Biology, Indraprastha Institute of Information Technology-Delhi (IIIT-Delhi), Okhla, Phase III, New Delhi, 110020, India.
| | - Gaurav Ahuja
- Department of Computational Biology, Indraprastha Institute of Information Technology-Delhi (IIIT-Delhi), Okhla, Phase III, New Delhi, 110020, India.
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9
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Thakkar Y, Moustakas H, Moelijker N, Hendriks G, Brandsma I, Pfuhler S, Api AM. Utility of ToxTracker in animal alternative testing strategy for fragrance materials. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2023; 64:234-243. [PMID: 36762970 DOI: 10.1002/em.22532] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 01/23/2023] [Accepted: 01/31/2023] [Indexed: 05/03/2023]
Abstract
To determine the utility of the ToxTracker assay in animal alternative testing strategies, the genotoxic potential of four fragrance materials (2-octen-4-one, lauric aldehyde, veratraldehyde, and p-methoxy cinnamaldehyde) were tested in the ToxTracker assay. These materials have been previously evaluated in an in vitro as well as in vivo micronucleus assay, conducted as per OECD guidelines. In addition to these studies, reconstructed human skin micronucleus studies were conducted on all four materials. All four materials were positive in an in vitro micronucleus assay but were negative in both in vivo and 3D skin micronucleus assays. The ToxTracker assay, in combination with in silico methods to predict metabolism was used to identify mechanisms for the misleading positive outcomes observed in the in vitro micronucleus assays. The results show that the ToxTracker assay, in conjunction with in silico predictions, can provide the information needed to aid in the identification of an appropriate animal alternative follow-up assay, for substances with positive results in the standard in vitro test battery. Thus, the ToxTracker assay is a valuable tool to identify the genotoxic potential of fragrance materials and can aid with replacing animal-based follow-up testing with appropriate animal alternative assay(s).
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Affiliation(s)
- Yax Thakkar
- Research Institute for Fragrance Materials, Inc, Woodcliff Lake, New Jersey, USA
| | - Holger Moustakas
- Research Institute for Fragrance Materials, Inc, Woodcliff Lake, New Jersey, USA
| | | | | | | | - Stefan Pfuhler
- The Procter & Gamble Company, Mason Business Centre, Mason, Ohio, USA
| | - Anne Marie Api
- Research Institute for Fragrance Materials, Inc, Woodcliff Lake, New Jersey, USA
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10
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Beal MA, Audebert M, Barton-Maclaren T, Battaion H, Bemis JC, Cao X, Chen C, Dertinger SD, Froetschl R, Guo X, Johnson G, Hendriks G, Khoury L, Long AS, Pfuhler S, Settivari RS, Wickramasuriya S, White P. Quantitative in vitro to in vivo extrapolation of genotoxicity data provides protective estimates of in vivo dose. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2023; 64:105-122. [PMID: 36495195 DOI: 10.1002/em.22521] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 11/29/2022] [Accepted: 11/30/2022] [Indexed: 06/17/2023]
Abstract
Genotoxicity assessment is a critical component in the development and evaluation of chemicals. Traditional genotoxicity assays (i.e., mutagenicity, clastogenicity, and aneugenicity) have been limited to dichotomous hazard classification, while other toxicity endpoints are assessed through quantitative determination of points-of-departures (PODs) for setting exposure limits. The more recent higher-throughput in vitro genotoxicity assays, many of which also provide mechanistic information, offer a powerful approach for determining defined PODs for potency ranking and risk assessment. In order to obtain relevant human dose context from the in vitro assays, in vitro to in vivo extrapolation (IVIVE) models are required to determine what dose would elicit a concentration in the body demonstrated to be genotoxic using in vitro assays. Previous work has demonstrated that application of IVIVE models to in vitro bioactivity data can provide PODs that are protective of human health, but there has been no evaluation of how these models perform with in vitro genotoxicity data. Thus, the Genetic Toxicology Technical Committee, under the Health and Environmental Sciences Institute, conducted a case study on 31 reference chemicals to evaluate the performance of IVIVE application to genotoxicity data. The results demonstrate that for most chemicals considered here (20/31), the PODs derived from in vitro data and IVIVE are health protective relative to in vivo PODs from animal studies. PODs were also protective by assay target: mutations (8/13 chemicals), micronuclei (9/12), and aneugenicity markers (4/4). It is envisioned that this novel testing strategy could enhance prioritization, rapid screening, and risk assessment of genotoxic chemicals.
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Affiliation(s)
- Marc A Beal
- Bureau of Chemical Safety, Health Products and Food Branch, Health Canada, Ottawa, Ontario, Canada
| | - Marc Audebert
- Toxalim UMR1331, Toulouse University, INRAE, Toulouse, France
| | - Tara Barton-Maclaren
- Existing Substances Risk Assessment Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
| | - Hannah Battaion
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
| | | | - Xuefei Cao
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA
| | - Connie Chen
- Health and Environmental Sciences Institute, Washington, District of Columbia, USA
| | | | | | - Xiaoqing Guo
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA
| | | | | | | | - Alexandra S Long
- Existing Substances Risk Assessment Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
| | - Stefan Pfuhler
- Global Product Stewardship, Procter & Gamble, Cincinnati, Ohio, USA
| | - Raja S Settivari
- Mammalian Toxicology Center, Corteva Agriscience, Newark, Delaware, USA
| | - Shamika Wickramasuriya
- Existing Substances Risk Assessment Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
| | - Paul White
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
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11
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Boisvert L, Derr R, Osterlund T, Hendriks G, Brandsma I. Quantitative interpretation of ToxTracker dose-response data for potency comparisons and mode-of-action determination. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2023; 64:132-143. [PMID: 36645179 DOI: 10.1002/em.22525] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 12/11/2022] [Accepted: 12/19/2022] [Indexed: 06/17/2023]
Abstract
ToxTracker is an in vitro mammalian stem cell-based reporter assay that detects activation of specific cellular signaling pathways (DNA damage, oxidative stress, and/or protein damage) upon chemical exposure using flow cytometry. Here we used quantitative methods to empirically analyze historical control data, and dose-response data across a wide range of reference chemicals. First, we analyzed historical control data to define a fold-change threshold for identification of a significant positive response. Next, we used the benchmark dose (BMD) combined-covariate approach for potency ranking of a set of more than 120 compounds; the BMD values were used for comparative identification of the most potent inducers of each reporter. Lastly, we used principal component analysis (PCA) to investigate functional and statistical relationships between the ToxTracker reporters. The PCA results, based on the BMD results for all substances, indicated that the DNA damage (Rtkn, Bscl2) and p53 (Btg2) reporters are functionally complementary and indicative of genotoxic stress. The oxidative stress (Srxn1 and Blvrb) and protein stress (Ddit3) reporters are independent indicators of cellular stress, and essential for toxicological profiling using the ToxTracker assay. Overall, dose-response modeling of multivariate ToxTracker data can be used for potency ranking and mode-of-action determination. In the future, IVIVE (in vitro to in vivo extrapolation) methods can be employed to determine in vivo AED (administered equivalent dose) values that can in turn be used for human health risk assessment.
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Affiliation(s)
- Lorrie Boisvert
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
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12
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Alijagic A, Scherbak N, Kotlyar O, Karlsson P, Wang X, Odnevall I, Benada O, Amiryousefi A, Andersson L, Persson A, Felth J, Andersson H, Larsson M, Hedbrant A, Salihovic S, Hyötyläinen T, Repsilber D, Särndahl E, Engwall M. A Novel Nanosafety Approach Using Cell Painting, Metabolomics, and Lipidomics Captures the Cellular and Molecular Phenotypes Induced by the Unintentionally Formed Metal-Based (Nano)Particles. Cells 2023; 12:281. [PMID: 36672217 PMCID: PMC9856453 DOI: 10.3390/cells12020281] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 01/01/2023] [Accepted: 01/09/2023] [Indexed: 01/12/2023] Open
Abstract
Additive manufacturing (AM) or industrial 3D printing uses cutting-edge technologies and materials to produce a variety of complex products. However, the effects of the unintentionally emitted AM (nano)particles (AMPs) on human cells following inhalation, require further investigations. The physicochemical characterization of the AMPs, extracted from the filter of a Laser Powder Bed Fusion (L-PBF) 3D printer of iron-based materials, disclosed their complexity, in terms of size, shape, and chemistry. Cell Painting, a high-content screening (HCS) assay, was used to detect the subtle morphological changes elicited by the AMPs at the single cell resolution. The profiling of the cell morphological phenotypes, disclosed prominent concentration-dependent effects on the cytoskeleton, mitochondria, and the membranous structures of the cell. Furthermore, lipidomics confirmed that the AMPs induced the extensive membrane remodeling in the lung epithelial and macrophage co-culture cell model. To further elucidate the biological mechanisms of action, the targeted metabolomics unveiled several inflammation-related metabolites regulating the cell response to the AMP exposure. Overall, the AMP exposure led to the internalization, oxidative stress, cytoskeleton disruption, mitochondrial activation, membrane remodeling, and metabolic reprogramming of the lung epithelial cells and macrophages. We propose the approach of integrating Cell Painting with metabolomics and lipidomics, as an advanced nanosafety methodology, increasing the ability to capture the cellular and molecular phenotypes and the relevant biological mechanisms to the (nano)particle exposure.
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Affiliation(s)
- Andi Alijagic
- Man-Technology-Environment Research Center (MTM), Örebro University, SE-701 82 Örebro, Sweden
- Inflammatory Response and Infection Susceptibility Centre (iRiSC), Faculty of Medicine and Health, Örebro University, SE-701 82 Örebro, Sweden
- Faculty of Medicine and Health, School of Medical Sciences, Örebro University, SE-701 82 Örebro, Sweden
| | - Nikolai Scherbak
- Man-Technology-Environment Research Center (MTM), Örebro University, SE-701 82 Örebro, Sweden
| | - Oleksandr Kotlyar
- Man-Technology-Environment Research Center (MTM), Örebro University, SE-701 82 Örebro, Sweden
- Centre for Applied Autonomous Sensor Systems (AASS), Mobile Robotics and Olfaction Lab (MRO), Örebro University, SE-701 82 Örebro, Sweden
| | - Patrik Karlsson
- Department of Mechanical Engineering, Örebro University, SE-701 82 Örebro, Sweden
| | - Xuying Wang
- KTH Royal Institute of Technology, Department of Chemistry, Division of Surface and Corrosion Science, SE-100 44 Stockholm, Sweden
| | - Inger Odnevall
- KTH Royal Institute of Technology, Department of Chemistry, Division of Surface and Corrosion Science, SE-100 44 Stockholm, Sweden
- AIMES—Center for the Advancement of Integrated Medical and Engineering Sciences at Karolinska Institutet and KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
- Department of Neuroscience, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Oldřich Benada
- Institute of Microbiology of the Czech Academy of Sciences, 140 00 Prague, Czech Republic
| | - Ali Amiryousefi
- Faculty of Medicine and Health, School of Medical Sciences, Örebro University, SE-701 82 Örebro, Sweden
| | - Lena Andersson
- Inflammatory Response and Infection Susceptibility Centre (iRiSC), Faculty of Medicine and Health, Örebro University, SE-701 82 Örebro, Sweden
- Faculty of Medicine and Health, School of Medical Sciences, Örebro University, SE-701 82 Örebro, Sweden
- Department of Occupational and Environmental Medicine, Örebro University Hospital, SE-701 85 Örebro, Sweden
| | - Alexander Persson
- Inflammatory Response and Infection Susceptibility Centre (iRiSC), Faculty of Medicine and Health, Örebro University, SE-701 82 Örebro, Sweden
- Faculty of Medicine and Health, School of Medical Sciences, Örebro University, SE-701 82 Örebro, Sweden
| | | | | | - Maria Larsson
- Man-Technology-Environment Research Center (MTM), Örebro University, SE-701 82 Örebro, Sweden
| | - Alexander Hedbrant
- Inflammatory Response and Infection Susceptibility Centre (iRiSC), Faculty of Medicine and Health, Örebro University, SE-701 82 Örebro, Sweden
- Faculty of Medicine and Health, School of Medical Sciences, Örebro University, SE-701 82 Örebro, Sweden
| | - Samira Salihovic
- Man-Technology-Environment Research Center (MTM), Örebro University, SE-701 82 Örebro, Sweden
- Inflammatory Response and Infection Susceptibility Centre (iRiSC), Faculty of Medicine and Health, Örebro University, SE-701 82 Örebro, Sweden
- Faculty of Medicine and Health, School of Medical Sciences, Örebro University, SE-701 82 Örebro, Sweden
| | - Tuulia Hyötyläinen
- Man-Technology-Environment Research Center (MTM), Örebro University, SE-701 82 Örebro, Sweden
| | - Dirk Repsilber
- Faculty of Medicine and Health, School of Medical Sciences, Örebro University, SE-701 82 Örebro, Sweden
| | - Eva Särndahl
- Inflammatory Response and Infection Susceptibility Centre (iRiSC), Faculty of Medicine and Health, Örebro University, SE-701 82 Örebro, Sweden
- Faculty of Medicine and Health, School of Medical Sciences, Örebro University, SE-701 82 Örebro, Sweden
| | - Magnus Engwall
- Man-Technology-Environment Research Center (MTM), Örebro University, SE-701 82 Örebro, Sweden
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13
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Pereira M, Macmillan DS, Willett C, Seidle T. REACHing for solutions: Essential revisions to the EU chemicals regulation to modernise safety assessment. Regul Toxicol Pharmacol 2022; 136:105278. [DOI: 10.1016/j.yrtph.2022.105278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 10/05/2022] [Accepted: 10/13/2022] [Indexed: 11/13/2022]
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Landsiedel R, Honarvar N, Seiffert SB, Oesch B, Oesch F. Genotoxicity testing of nanomaterials. WIRES NANOMEDICINE AND NANOBIOTECHNOLOGY 2022; 14:e1833. [DOI: 10.1002/wnan.1833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 06/02/2022] [Accepted: 06/06/2022] [Indexed: 11/24/2022]
Affiliation(s)
- Robert Landsiedel
- Experimental Toxicology and Ecology BASF SE Ludwigshafen am Rhein Germany
- Pharmacy, Pharmacology and Toxicology Free University of Berlin Berlin Germany
| | - Naveed Honarvar
- Experimental Toxicology and Ecology BASF SE Ludwigshafen am Rhein Germany
| | | | - Barbara Oesch
- Oesch‐Tox Toxicological Consulting and Expert Opinions, GmbH & Co KG Ingelheim Germany
| | - Franz Oesch
- Oesch‐Tox Toxicological Consulting and Expert Opinions, GmbH & Co KG Ingelheim Germany
- Institute of Toxicology Johannes Gutenberg University Mainz Germany
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15
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Mišík M, Nersesyan A, Ferk F, Holzmann K, Krupitza G, Herrera Morales D, Staudinger M, Wultsch G, Knasmueller S. Search for the optimal genotoxicity assay for routine testing of chemicals: Sensitivity and specificity of conventional and new test systems. MUTATION RESEARCH. GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2022; 881:503524. [PMID: 36031336 DOI: 10.1016/j.mrgentox.2022.503524] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 06/15/2022] [Accepted: 06/28/2022] [Indexed: 06/15/2023]
Abstract
Many conventional in vitro tests that are currently widely used for routine screening of chemicals have a sensitivity/specificity in the range between 60 % and 80 % for the detection of carcinogens. Most procedures were developed 30-40 years ago. In the last decades several assays became available which are based on the use of metabolically competent cell lines, improvement of the cultivation conditions and development of new endpoints. Validation studies indicate that some of these models may be more reliable for the detection of genotoxicants (i.e. many of them have sensitivity and specificity values between 80 % and 95 %). Therefore, they could replace conventional tests in the future. The bone marrow micronucleus (MN) assay with rodents is at present the most widely used in vivo test. The majority of studies indicate that it detects only 5-6 out of 10 carcinogens while experiments with transgenic rodents and comet assays seem to have a higher predictive value and detect genotoxic carcinogens that are negative in MN experiments. Alternatives to rodent experiments could be MN experiments with hen eggs or their replacement by combinations of new in vitro tests. Examples for promising candidates are ToxTracker, TGx-DDI, multiplex flow cytometry, γH2AX experiments, measurement of p53 activation and MN experiments with metabolically competent human derived liver cells. However, the realization of multicentric collaborative validation studies is mandatory to identify the most reliable tests.
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Affiliation(s)
- M Mišík
- Center for Cancer Research, Medical University of Vienna, Borschkegasse 8a, A-1090 Vienna, Austria
| | - A Nersesyan
- Center for Cancer Research, Medical University of Vienna, Borschkegasse 8a, A-1090 Vienna, Austria
| | - F Ferk
- Center for Cancer Research, Medical University of Vienna, Borschkegasse 8a, A-1090 Vienna, Austria
| | - K Holzmann
- Center for Cancer Research, Medical University of Vienna, Borschkegasse 8a, A-1090 Vienna, Austria
| | - G Krupitza
- Department of Pathology, Medical University of Vienna, A-1090 Vienna, Austria
| | - D Herrera Morales
- Center for Cancer Research, Medical University of Vienna, Borschkegasse 8a, A-1090 Vienna, Austria
| | - M Staudinger
- Center for Cancer Research, Medical University of Vienna, Borschkegasse 8a, A-1090 Vienna, Austria
| | - G Wultsch
- Center for Cancer Research, Medical University of Vienna, Borschkegasse 8a, A-1090 Vienna, Austria
| | - S Knasmueller
- Center for Cancer Research, Medical University of Vienna, Borschkegasse 8a, A-1090 Vienna, Austria.
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16
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Allemang A, Lester C, Roth T, Pfuhler S, Peuschel H, Kosemund K, Mahony C, Bergeland T, O'Keeffe L. Assessing the genotoxicity and carcinogenicity of 2-chloroethanol through structure activity relationships and in vitro testing approaches. Food Chem Toxicol 2022; 168:113290. [PMID: 35863484 DOI: 10.1016/j.fct.2022.113290] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 06/16/2022] [Accepted: 07/08/2022] [Indexed: 11/25/2022]
Abstract
The detection of 2-chloroethanol in foods generally follows an assumption that the pesticide ethylene oxide has been used at some stage in the supply chain. In this situation the Pesticide Residues in Food Regulation (EC) 396/2005 requires 2-chloroethanol to be assessed as if equivalent to ethylene oxide, which has been classified as a genotoxic carcinogen. This review investigated whether this is an appropriate risk assessment approach for 2-chloroethanol. This involved an assessment of existing genotoxicity and carcinogenicity data, application of Structure Activity Based Read Across for carcinogenicity assessment, biological reactivity in the ToxTracker assay and micronuclei formation in HepaRG cells. Although we identified there is an absence of a standard oral bioassay for 2-chloroethanol, carcinogenicity weight-of-evidence assessment along with data on relevant structural analogues do not show evidence for carcinogenicity for 2-chloroethanol. The absence of genotoxicity was demonstrated for 2-chloroethanol and suitable analogues. In contrast, ethylene oxide showed reactivity towards markers indicative of direct DNA damage which is consistent with what is known about its mode-of-action. These data facilitate the understanding of 2-chloroethanol and given that it is not a genotoxic carcinogen suggest it must be assessed relative to non-cancer endpoints and a health protective Reference Dose should be established on that basis.
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Affiliation(s)
| | - Cathy Lester
- The Procter & Gamble Company, Cincinnati, OH, USA
| | - Thomas Roth
- SCC Scientific Consulting Company GmbH, Am Grenzgraben 11, 55545, Bad Kreuznach, Germany
| | | | - Henrike Peuschel
- SCC Scientific Consulting Company GmbH, Am Grenzgraben 11, 55545, Bad Kreuznach, Germany
| | - Kirstin Kosemund
- Procter & Gamble Service GmbH, Sulzbacher Str. 40, 65824, Schwalbach am Taunus, Germany
| | | | | | - Lara O'Keeffe
- The Procter & Gamble Company, Reading, Berkshire, UK.
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17
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Kuo B, Beal MA, Wills JW, White PA, Marchetti F, Nong A, Barton-Maclaren TS, Houck K, Yauk CL. Comprehensive interpretation of in vitro micronucleus test results for 292 chemicals: from hazard identification to risk assessment application. Arch Toxicol 2022; 96:2067-2085. [PMID: 35445829 PMCID: PMC9151546 DOI: 10.1007/s00204-022-03286-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 02/23/2022] [Indexed: 11/08/2022]
Abstract
Risk assessments are increasingly reliant on information from in vitro assays. The in vitro micronucleus test (MNvit) is a genotoxicity test that detects chromosomal abnormalities, including chromosome breakage (clastogenicity) and/or whole chromosome loss (aneugenicity). In this study, MNvit datasets for 292 chemicals, generated by the US EPA's ToxCast program, were evaluated using a decision tree-based pipeline for hazard identification. Chemicals were tested with 19 concentrations (n = 1) up to 200 µM, in the presence and absence of Aroclor 1254-induced rat liver S9. To identify clastogenic chemicals, %MN values at each concentration were compared to a distribution of batch-specific solvent controls; this was followed by cytotoxicity assessment and benchmark concentration (BMC) analyses. The approach classified 157 substances as positives, 25 as negatives, and 110 as inconclusive. Using the approach described in Bryce et al. (Environ Mol Mutagen 52:280-286, 2011), we identified 15 (5%) aneugens. IVIVE (in vitro to in vivo extrapolation) was employed to convert BMCs into administered equivalent doses (AEDs). Where possible, AEDs were compared to points of departure (PODs) for traditional genotoxicity endpoints; AEDs were generally lower than PODs based on in vivo endpoints. To facilitate interpretation of in vitro MN assay concentration-response data for risk assessment, exposure estimates were utilized to calculate bioactivity exposure ratio (BER) values. BERs for 50 clastogens and two aneugens had AEDs that approached exposure estimates (i.e., BER < 100); these chemicals might be considered priorities for additional testing. This work provides a framework for the use of high-throughput in vitro genotoxicity testing for priority setting and chemical risk assessment.
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Affiliation(s)
- Byron Kuo
- Environmental Health Science and Research Bureau, Environmental and Radiation Health Sciences Directorate, Healthy Environment and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada
| | - Marc A Beal
- Bureau of Chemical Safety, Food Directorate, Health Products and Food Branch, Health Canada, Ottawa, ON, Canada
| | - John W Wills
- Environmental Health Science and Research Bureau, Environmental and Radiation Health Sciences Directorate, Healthy Environment and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada
- Biominerals Research, Department of Veterinary Medicine, University of Cambridge, Cambridge, CB3 0ES, UK
| | - Paul A White
- Environmental Health Science and Research Bureau, Environmental and Radiation Health Sciences Directorate, Healthy Environment and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada
| | - Francesco Marchetti
- Environmental Health Science and Research Bureau, Environmental and Radiation Health Sciences Directorate, Healthy Environment and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada
| | - Andy Nong
- Environmental Health Science and Research Bureau, Environmental and Radiation Health Sciences Directorate, Healthy Environment and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada
| | - Tara S Barton-Maclaren
- Existing Substances Risk Assessment Bureau, Safe Environments Directorate, Healthy Environment and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada
| | - Keith Houck
- National Center for Computational Toxicology, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, 27711, USA
| | - Carole L Yauk
- Environmental Health Science and Research Bureau, Environmental and Radiation Health Sciences Directorate, Healthy Environment and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada.
- Department of Biology, University of Ottawa, 30 Marie Curie Private, Room 269, Ottawa, ON, K1N 6N5, Canada.
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Li Y, Yang X, Peng L, Xia Q, Zhang Y, Huang W, Liu T, Jia D. Role of Seipin in Human Diseases and Experimental Animal Models. Biomolecules 2022; 12:biom12060840. [PMID: 35740965 PMCID: PMC9221541 DOI: 10.3390/biom12060840] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/13/2022] [Accepted: 06/14/2022] [Indexed: 02/05/2023] Open
Abstract
Seipin, a protein encoded by the Berardinelli-Seip congenital lipodystrophy type 2 (BSCL2) gene, is famous for its key role in the biogenesis of lipid droplets and type 2 congenital generalised lipodystrophy (CGL2). BSCL2 gene mutations result in genetic diseases including CGL2, progressive encephalopathy with or without lipodystrophy (also called Celia’s encephalopathy), and BSCL2-associated motor neuron diseases. Abnormal expression of seipin has also been found in hepatic steatosis, neurodegenerative diseases, glioblastoma stroke, cardiac hypertrophy, and other diseases. In the current study, we comprehensively summarise phenotypes, underlying mechanisms, and treatment of human diseases caused by BSCL2 gene mutations, paralleled by animal studies including systemic or specific Bscl2 gene knockout, or Bscl2 gene overexpression. In various animal models representing diseases that are not related to Bscl2 mutations, differential expression patterns and functional roles of seipin are also described. Furthermore, we highlight the potential therapeutic approaches by targeting seipin or its upstream and downstream signalling pathways. Taken together, restoring adipose tissue function and targeting seipin-related pathways are effective strategies for CGL2 treatment. Meanwhile, seipin-related pathways are also considered to have potential therapeutic value in diseases that are not caused by BSCL2 gene mutations.
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Affiliation(s)
- Yuying Li
- West China Pancreatitis Centre, Centre for Integrated Traditional Chinese Medicine and Western Medicine, West China-Liverpool Biomedical Research Centre, West China Hospital, Sichuan University, Chengdu 610041, China; (Y.L.); (X.Y.); (Q.X.)
| | - Xinmin Yang
- West China Pancreatitis Centre, Centre for Integrated Traditional Chinese Medicine and Western Medicine, West China-Liverpool Biomedical Research Centre, West China Hospital, Sichuan University, Chengdu 610041, China; (Y.L.); (X.Y.); (Q.X.)
| | - Linrui Peng
- Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, Chengdu 610041, China; (L.P.); (Y.Z.)
| | - Qing Xia
- West China Pancreatitis Centre, Centre for Integrated Traditional Chinese Medicine and Western Medicine, West China-Liverpool Biomedical Research Centre, West China Hospital, Sichuan University, Chengdu 610041, China; (Y.L.); (X.Y.); (Q.X.)
| | - Yuwei Zhang
- Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, Chengdu 610041, China; (L.P.); (Y.Z.)
| | - Wei Huang
- West China Pancreatitis Centre, Centre for Integrated Traditional Chinese Medicine and Western Medicine, West China-Liverpool Biomedical Research Centre, West China Hospital, Sichuan University, Chengdu 610041, China; (Y.L.); (X.Y.); (Q.X.)
- Institutes for Systems Genetics & Immunology and Inflammation, Frontiers Science Center for Disease-Related Molecular Network, West China Hospital, Sichuan University, Chengdu 610041, China
- Correspondence: (W.H.); (T.L.)
| | - Tingting Liu
- West China Pancreatitis Centre, Centre for Integrated Traditional Chinese Medicine and Western Medicine, West China-Liverpool Biomedical Research Centre, West China Hospital, Sichuan University, Chengdu 610041, China; (Y.L.); (X.Y.); (Q.X.)
- Correspondence: (W.H.); (T.L.)
| | - Da Jia
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Paediatrics, West China Second University Hospital, State Key Laboratory of Biotherapy and Collaborative Innovation Center of Biotherapy, Sichuan University, Chengdu 610041, China;
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Smart DE, Bozhilova S, Miazzi F, Haswell LE, Gaca MD, Thorne D, Breheny D. Application of ToxTracker for the toxicological assessment of tobacco and nicotine delivery products. Toxicol Lett 2022; 358:59-68. [PMID: 35065211 DOI: 10.1016/j.toxlet.2022.01.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 01/06/2022] [Accepted: 01/17/2022] [Indexed: 12/15/2022]
Abstract
Consumer demands and innovation have led to an increasingly diverse range of nicotine delivery systems, driven by a desire to reduce risk associated with traditional combustible cigarettes. This speed of change provides a mandate for rapid new product assessment. We have used the validated technology ToxTracker®, to assess biomarkers of DNA damage, protein misfolding, oxidative and cellular stress, across the categories of cigarette (1R6F), tobacco heating product (THP 1.4) and electronic cigarette (ePen 3). In addition, we compared the commonly used test matrices for tobacco and nicotine products; whole aerosol aqueous extracts (AqE) and gas vapour phase (GVP), determining their suitability across the product categories. We demonstrated a significant reduction in oxidative stress and cytotoxicity for THP 1.4 over cigarette, further reduced for ePen 3, when assessed by both dilution and nicotine dosimetry. We also identified that while the extraction matrices AqE and GVP from combustible products were equivalent in the induced responses, this was not true of the other category examples, moreover THP 1.4 GVP demonstrates a >50 % reduction in both toxicity and cytotoxicity endpoints over AqE. This indicates that unlike cigarette, the active components or toxicants for THP and electronic cigarette are associated with the aerosol fraction of these categories.
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Affiliation(s)
- David E Smart
- British American Tobacco, Scientific Research, Waterhouse Way, Southampton, SO15 8TL, UK.
| | - Stela Bozhilova
- British American Tobacco, Scientific Research, Waterhouse Way, Southampton, SO15 8TL, UK
| | - Fabio Miazzi
- British American Tobacco, Scientific Research, Waterhouse Way, Southampton, SO15 8TL, UK
| | - Linsey E Haswell
- British American Tobacco, Scientific Research, Waterhouse Way, Southampton, SO15 8TL, UK
| | - Marianna D Gaca
- British American Tobacco, Scientific Research, Waterhouse Way, Southampton, SO15 8TL, UK
| | - David Thorne
- British American Tobacco, Scientific Research, Waterhouse Way, Southampton, SO15 8TL, UK
| | - Damien Breheny
- British American Tobacco, Scientific Research, Waterhouse Way, Southampton, SO15 8TL, UK
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20
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Cho E, Allemang A, Audebert M, Chauhan V, Dertinger S, Hendriks G, Luijten M, Marchetti F, Minocherhomji S, Pfuhler S, Roberts DJ, Trenz K, Yauk CL. AOP report: Development of an adverse outcome pathway for oxidative DNA damage leading to mutations and chromosomal aberrations. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2022; 63:118-134. [PMID: 35315142 PMCID: PMC9322445 DOI: 10.1002/em.22479] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 03/18/2022] [Indexed: 05/22/2023]
Abstract
The Genetic Toxicology Technical Committee (GTTC) of the Health and Environmental Sciences Institute (HESI) is developing adverse outcome pathways (AOPs) that describe modes of action leading to potentially heritable genomic damage. The goal was to enhance the use of mechanistic information in genotoxicity assessment by building empirical support for the relationships between relevant molecular initiating events (MIEs) and regulatory endpoints in genetic toxicology. Herein, we present an AOP network that links oxidative DNA damage to two adverse outcomes (AOs): mutations and chromosomal aberrations. We collected empirical evidence from the literature to evaluate the key event relationships between the MIE and the AOs, and assessed the weight of evidence using the modified Bradford-Hill criteria for causality. Oxidative DNA damage is constantly induced and repaired in cells given the ubiquitous presence of reactive oxygen species and free radicals. However, xenobiotic exposures may increase damage above baseline levels through a variety of mechanisms and overwhelm DNA repair and endogenous antioxidant capacity. Unrepaired oxidative DNA base damage can lead to base substitutions during replication and, along with repair intermediates, can also cause DNA strand breaks that can lead to mutations and chromosomal aberrations if not repaired adequately. This AOP network identifies knowledge gaps that could be filled by targeted studies designed to better define the quantitative relationships between key events, which could be leveraged for quantitative chemical safety assessment. We anticipate that this AOP network will provide the building blocks for additional genotoxicity-associated AOPs and aid in designing novel integrated testing approaches for genotoxicity.
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Affiliation(s)
- Eunnara Cho
- Environmental Health Science and Research BureauHealth CanadaOttawaOntarioCanada
- Department of BiologyCarleton UniversityOttawaOntarioCanada
| | | | | | - Vinita Chauhan
- Consumer and Clinical Radiation Protection BureauHealth CanadaOttawaOntarioCanada
| | | | | | - Mirjam Luijten
- Centre for Health ProtectionNational Institute for Public Health and the Environment (RIVM)BilthovenThe Netherlands
| | - Francesco Marchetti
- Environmental Health Science and Research BureauHealth CanadaOttawaOntarioCanada
- Department of BiologyCarleton UniversityOttawaOntarioCanada
| | - Sheroy Minocherhomji
- Amgen Research, Translational Safety and Bioanalytical SciencesAmgen Inc.Thousand OaksCaliforniaUSA
| | | | | | | | - Carole L. Yauk
- Environmental Health Science and Research BureauHealth CanadaOttawaOntarioCanada
- Department of BiologyCarleton UniversityOttawaOntarioCanada
- Department of BiologyUniversity of OttawaOttawaOntarioCanada
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21
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EFSA (European Food Safety Authority), Borroto J, Castoldi AF, Chiusolo A, Colagiorgi A, Colas M, Crivellente F, De Lentdecker C, Istace F, Kardassi D, Mangas I, Molnar T, Parra Morte JM, Terron A, Tiramani M. Statement on the BfR opinion regarding the toxicity of 2-chloroethanol. EFSA J 2022; 20:e07147. [PMID: 35237354 PMCID: PMC8875132 DOI: 10.2903/j.efsa.2022.7147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
In accordance with Art. 31(1) of Regulation (EC) No 178/2002, the Commission asked EFSA to provide a scientific review on the BfR opinion on the 'Health risk assessment of ethylene oxide residues in sesame seeds' (Opinion No 024/2021) regarding the toxicity of 2-chloroethanol. In addition, EFSA was asked to clarify under which circumstances the use of the MOE approach is considered appropriate. Based on the information available to EFSA, i.e. the studies assessed in the frame of the BfR opinion and additional data provided by stakeholders not assessed by BfR, EFSA considers the genotoxicity of 2-chloroethanol as inconclusive. On this basis, EFSA would not recommend setting reference points for risk assessment or health-based guidance values until the genotoxic potential of 2-chloroethanol is clarified. EFSA therefore recommends performing new in vitro gene mutation and in vitro micronucleus tests with 2-chloroethanol following the recommendations of the most recent OECD technical guidelines to clarify its genotoxic potential. If the result of any of the test is positive, the recommendations of the EFSA Scientific Committee (2011) should be followed. If the genotoxic potential of 2-chloroethanol is finally clarified and overall negative, EFSA would recommend setting the reference point for deriving health-based guidance values based on existing toxicity studies on 2-chloroethanol.
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A tiered approach to investigate the inhalation toxicity of cobalt substances. Tier 2 b: Reactive cobalt substances induce oxidative stress in ToxTracker and activate hypoxia target genes. Regul Toxicol Pharmacol 2022; 129:105120. [PMID: 35038485 DOI: 10.1016/j.yrtph.2022.105120] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 12/17/2021] [Accepted: 01/06/2022] [Indexed: 12/12/2022]
Abstract
Cobalt metal and cobalt sulfate are carcinogenic in rodents following inhalation exposure. The pre-carcinogenic effects associated with exposure to these cobalt substances include oxidative stress and genotoxicity. Some, but not all, cobalt substances induce in vitro clastogenicity or an increase in micronuclei. As a result, these substances are classified genotoxic carcinogens, having major impacts on their risk assessment, e.g. assumption of a non-thresholded dose response. Here, we investigated the potential of nine cobalt substances to cause genotoxicity and oxidative stress using the ToxTracker assay, with an extension to measure biomarkers of hypoxia. None of the nine tested substances activated the DNA damage markers in ToxTracker, and five substances activated the oxidative stress response reporters. The same five substances also activated the expression of several hypoxia target genes. Consistent with the lower tier of testing found in the preceding paper of this series, these compounds can be grouped based on their ability to release bioavailable cobalt ion and to trigger subsequent key events.
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23
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Beal MA, Gagne M, Kulkarni SA, Patlewicz G, Thomas RS, Barton-Maclaren TS. Implementing in vitro bioactivity data to modernize priority setting of chemical inventories. ALTEX 2022; 39:123-139. [PMID: 34818430 PMCID: PMC8973434 DOI: 10.14573/altex.2106171] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 11/22/2021] [Indexed: 01/03/2023]
Abstract
Internationally, there are thousands of existing and newly introduced chemicals in commerce, highlighting the ongoing importance of innovative approaches to identify emerging chemicals of concern. For many chemicals, there is a paucity of hazard and exposure data. Thus, there is a crucial need for efficient and robust approaches to address data gaps and support risk-based prioritization. Several studies have demonstrated the utility of in vitro bioactivity data from the ToxCast program in deriving points of departure (PODs). ToxCast contains data for nearly 1,400 endpoints per chemical, and the bioactivity concentrations, indicative of potential adverse outcomes, can be converted to human-equivalent PODs using high-throughput toxicokinetics (HTTK) modeling. However, data gaps need to be addressed for broader application: the limited chemical space of HTTK and quantitative high-throughput screening data. Here we explore the applicability of in silico models to address these data needs. Specifically, we used ADMET predictor for HTTK predictions and a generalized read-across approach to predict ToxCast bioactivity potency. We applied these models to profile 5,801 chemicals on Canada’s Domestic Substances List (DSL). To evaluate the approach’s performance, bioactivity PODs were compared with in vivo results from the EPA Toxicity Values database for 1,042 DSL chemicals. Comparisons demonstrated that the bioactivity PODs, based on ToxCast data or read-across, were conservative for 95% of the chemicals. Comparing bioactivity PODs to human exposure estimates supports the identification of chemicals of potential interest for further work. The bioactivity workflow shows promise as a powerful screening tool to support effective triaging of chemical inventories.
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Affiliation(s)
- Marc A. Beal
- Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Canada
| | - Matthew Gagne
- Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Canada
| | - Sunil A. Kulkarni
- Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Canada
| | - Grace Patlewicz
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Russell S. Thomas
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
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25
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Karengera A, Bao C, Riksen JAG, van Veelen HPJ, Sterken MG, Kammenga JE, Murk AJ, Dinkla IJT. Development of a transcription-based bioanalytical tool to quantify the toxic potencies of hydrophilic compounds in water using the nematode Caenorhabditis elegans. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 227:112923. [PMID: 34700171 DOI: 10.1016/j.ecoenv.2021.112923] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 09/16/2021] [Accepted: 10/18/2021] [Indexed: 05/14/2023]
Abstract
Low concentrations of environmental contaminants can be difficult to detect with current analytical tools, yet they may pose a risk to human and environmental health. The development of bioanalytical tools can help to quantify toxic potencies of biologically active compounds even of hydrophilic contaminants that are hard to extract from water samples. In this study, we exposed the model organism Caenorhabditis elegans synchronized in larval stage L4 to hydrophilic compounds via the water phase and analyzed the effect on gene transcription abundance. The nematodes were exposed to three direct-acting genotoxicants (1 mM and 5 mM): N-ethyl-N-nitrosourea (ENU), formaldehyde (HCHO), and methyl methanesulfonate (MMS). Genome-wide gene expression analysis using microarrays revealed significantly altered transcription levels of 495 genes for HCHO, 285 genes for ENU, and 569 genes for MMS in a concentration-dependent manner. A relatively high number of differentially expressed genes was downregulated, suggesting a general stress in nematodes treated with toxicants. Gene ontology and Kyoto encyclopedia of genes and genomes analysis demonstrated that the upregulated genes were primarily associated with metabolism, xenobiotic detoxification, proteotoxic stress, and innate immune response. Interestingly, genes downregulated by MMS were linked to the inhibition of neurotransmission, and this is in accordance with the observed decreased locomotion in MMS-exposed nematodes. Unexpectedly, the expression level of DNA damage response genes such as cell-cycle checkpoints or DNA-repair proteins were not altered. Overall, the current study shows that gene expression profiling of nematodes can be used to identify the potential mechanisms underlying the toxicity of chemical compounds. C. elegans is a promising test organism to further develop into a bioanalytical tool for quantification of the toxic potency of a wide array of hydrophilic contaminants.
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Affiliation(s)
- Antoine Karengera
- Wageningen University, Department of Animal Sciences, Marine Animal Ecology Group, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands; Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA Leeuwarden, The Netherlands.
| | - Cong Bao
- Wageningen University, Department of Animal Sciences, Marine Animal Ecology Group, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands; Yangtze Delta Region Institute of Tsinghua University, Jiaxing, China
| | - Joost A G Riksen
- Wageningen University, Plant Sciences, Laboratory of Nematology, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - H Pieter J van Veelen
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA Leeuwarden, The Netherlands
| | - Mark G Sterken
- Wageningen University, Plant Sciences, Laboratory of Nematology, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Jan E Kammenga
- Wageningen University, Plant Sciences, Laboratory of Nematology, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Albertinka J Murk
- Wageningen University, Department of Animal Sciences, Marine Animal Ecology Group, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Inez J T Dinkla
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA Leeuwarden, The Netherlands
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26
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Avlasevich S, Pellegrin T, Godse M, Bryce S, Bemis J, Bajorski P, Dertinger S. Biomarkers of DNA damage response improve in vitro micronucleus assays by revealing genotoxic mode of action and reducing the occurrence of irrelevant positive results. Mutagenesis 2021; 36:407-418. [PMID: 34718711 DOI: 10.1093/mutage/geab039] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 10/25/2021] [Indexed: 11/12/2022] Open
Abstract
We have previously described two flow cytometry-based in vitro genotoxicity tests: micronucleus (MN) scoring (MicroFlow®) and a multiplexed DNA damage response biomarker assay (MultiFlow®). Here, we describe a strategy for combining the assays in order to efficiently supplement MN analyses with a panel of biomarkers that comment on cytotoxicity (i.e. relative nuclei count, relative increased nuclei count, cleaved PARP-positive chromatin and ethidium monoazide-positive chromatin) and genotoxic mode of action (MoA; i.e. γH2AX, phospho-histone H3, p53 activation and polyploidy). For these experiments, human TK6 cells were exposed to each of 32 well-studied reference chemicals in 96-well plates for 24 continuous hours. The test chemicals were evaluated over a range of concentrations in the presence and absence of a rat liver S9-based metabolic activation system. MultiFlow assay data were acquired at 4 and 24 h, and micronuclei were scored at 24 h. Testing 32 chemicals in two metabolic activation arms translated into 64 a priori calls: 42 genotoxicants and 22 non-genotoxicants. The MN assay showed high sensitivity and moderate specificity (90% and 68%, respectively). When a genotoxic call required significant MN and MultiFlow responses, specificity increased to 95% without adversely affecting sensitivity. The dose-response data were analysed with PROAST Benchmark Dose (BMD) software in order to calculate potency metrics for each endpoint, and ToxPi software was used to synthesise the resulting lower and upper bound 90% confidence intervals into visual profiles. The BMD/ToxPi combination was found to represent a powerful strategy for synthesising multiple BMD confidence intervals, as the software output provided MoA information as well as insights into genotoxic potency.
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Affiliation(s)
| | - Tina Pellegrin
- Litron Laboratories, 3500 Winton Place, Rochester, NY 14623, USA
| | - Manali Godse
- Department of Mathematics, Rochester Institute of Technology, 1 Lomb Memorial Drive, Rochester, NY 14623, USA
| | - Steven Bryce
- Litron Laboratories, 3500 Winton Place, Rochester, NY 14623, USA
| | - Jeffrey Bemis
- Litron Laboratories, 3500 Winton Place, Rochester, NY 14623, USA
| | - Peter Bajorski
- Department of Mathematics, Rochester Institute of Technology, 1 Lomb Memorial Drive, Rochester, NY 14623, USA
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Ter Braak B, Niemeijer M, Wolters L, Le Dévédec S, Bouwman P, van de Water B. Towards an advanced testing strategy for genotoxicity using image-based 2D and 3D HepG2 DNA damage response fluorescent protein reporters. Mutagenesis 2021; 37:130-142. [PMID: 34448005 PMCID: PMC9071099 DOI: 10.1093/mutage/geab031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Accepted: 08/26/2021] [Indexed: 11/26/2022] Open
Abstract
In vitro assessment of mutagenicity is an essential component in the chemical risk assessment. Given the diverse modes of action by which chemicals can induce DNA damage, it is essential that these in vitro assays are carefully evaluated for their possibilities and limitations. In this study, we used a fluorescent protein HepG2 reporter test system in combination with high content imaging. To measure induction of the DNA damage response (DDR), we used three different green fluorescent protein reporters for p53 pathway activation. These allowed for accurate quantification of p53, p21 and BTG2 (BTG anti-proliferation factor 2) protein expression and cell viability parameters at a single cell or spheroid resolution. The reporter lines were cultured as 2D monolayers and as 3D spheroids. Furthermore, liver maturity and cytochrome P450 enzyme expression were increased by culturing in an amino acid-rich (AAGLY) medium. We found that culture conditions that support a sustained proliferative state (2D culturing with normal DMEM medium) give superior sensitivity when genotoxic compounds are tested that do not require metabolisation and of which the mutagenic mode of action is dependent on replication. For compounds, which are metabolically converted to mutagenic metabolites, more differentiated HepG2 DDR reporters (e.g. 3D cultures) showed a higher sensitivity. This study stratifies how different culture methods of HepG2 DDR reporter cells can influence the sensitivity towards diverse genotoxicants and how this provides opportunities for a tiered genotoxicity testing strategy.
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Affiliation(s)
- Bas Ter Braak
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Leiden, the Netherlands
| | - Marije Niemeijer
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Leiden, the Netherlands
| | - Liesanne Wolters
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Leiden, the Netherlands
| | - Sylvia Le Dévédec
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Leiden, the Netherlands
| | - Peter Bouwman
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Leiden, the Netherlands
| | - Bob van de Water
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Leiden, the Netherlands
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28
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Pinter E, Friedl C, Irnesberger A, Czerny T, Piwonka T, Peñarroya A, Tacker M, Riegel E. HepGentox: a novel promising HepG2 reportergene-assay for the detection of genotoxic substances in complex mixtures. PeerJ 2021; 9:e11883. [PMID: 34395098 PMCID: PMC8323594 DOI: 10.7717/peerj.11883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 07/09/2021] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND In risk assessment, genotoxicity is a key factor to determine the safety for the consumer. Most in vitro genotoxicity assays were developed for the assessment of pure substances. However, in recent years more attention has been given to complex mixtures, where usually low amounts of a substance are present. For high-throughput screening, a toxicologically sensitive assay should be used, covering a broad range of genotoxic substances and detecting them at low concentrations. HepG2 cells have been recommended as one of the prime candidates for genotoxicity testing, as they are p53 competent, less prone towards cytotoxic effects and tend to have some metabolic activity. METHODS A HepG2 liver cell line was characterized for its suitability for genotoxicity assessment. For this, a luciferase based reporter gene assay revolving around the p53 pathway was validated for the analysis of pure substances and of complex mixtures. Further, the cell's capability to detect genotoxins correctly with and without an exogenous metabolizing system, namely rat liver S9, was assessed. RESULTS The assay proved to have a high toxicological sensitivity (87.5%) and specificity (94%). Further, the endogenous metabolizing system of the HepG2 cells was able to detect some genotoxins, which are known to depend on an enzymatic system. When complex mixtures were added this did not lead to any adverse effects concerning the assays performance and cytotoxicity was not an issue. DISCUSSION The HepGentox proved to have a high toxicological sensitivity and specificity for the tested substances, with similar or even lower lowest effective concentration (LEC) values, compared to other regulatory mammalian assays. This combines some important aspects in one test system, while also being less time and material consuming and covering several genotoxicity endpoints. As the assay performs well with and without an exogenous metabolizing system, no animal liver fractions have to be used, which application is discussed controversially and is considered to be expensive and laborious in sample testing. Because of this, the HepGentox is suitable for a cost-efficient first screening approach to obtain important information with human cells for further approaches, with a relatively fast and easy method. Therefore, the HepGentox is a promising assay to detect genotoxic substances correctly in complex mixtures even at low concentrations, with the potential for a high throughput application. In a nutshell, as part of an in vitro bioassay test battery, this assay could provide valuable information for complex mixtures.
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Affiliation(s)
- Elisabeth Pinter
- Departement of Applied Life Sciences, University of Applied Sciences Vienna, FH Campus Wien, Vienna, Austria
| | - Christina Friedl
- Departement of Applied Life Sciences, University of Applied Sciences Vienna, FH Campus Wien, Vienna, Austria
| | - Alexandra Irnesberger
- Departement of Applied Life Sciences, University of Applied Sciences Vienna, FH Campus Wien, Vienna, Austria
| | - Thomas Czerny
- Departement of Applied Life Sciences, University of Applied Sciences Vienna, FH Campus Wien, Vienna, Austria
| | - Tina Piwonka
- Departement of Applied Life Sciences, University of Applied Sciences Vienna, FH Campus Wien, Vienna, Austria
| | - Alfonso Peñarroya
- Departement of Applied Life Sciences, University of Applied Sciences Vienna, FH Campus Wien, Vienna, Austria
| | - Manfred Tacker
- Departement of Applied Life Sciences, University of Applied Sciences Vienna, FH Campus Wien, Vienna, Austria
| | - Elisabeth Riegel
- Departement of Applied Life Sciences, University of Applied Sciences Vienna, FH Campus Wien, Vienna, Austria
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29
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Wills JW, Halkes-Wellstead E, Summers HD, Rees P, Johnson GE. Empirical Comparison of Genotoxic Potency Estimations: The In Vitro DNA-Damage ToxTracker Endpoints versus the In Vivo Micronucleus Assay. Mutagenesis 2021; 36:311-320. [PMID: 34111295 PMCID: PMC8391785 DOI: 10.1093/mutage/geab020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 06/09/2021] [Indexed: 11/30/2022] Open
Abstract
Genetic toxicology is an essential component of compound safety assessment. In the face of a barrage of new compounds, higher throughput, less ethically divisive in vitro approaches capable of effective, human-relevant hazard identification and prioritisation are increasingly important. One such approach is the ToxTracker assay, which utilises murine stem cell lines equipped with green fluorescent protein (GFP)-reporter gene constructs that each inform on distinct aspects of cellular perturbation. Encouragingly, ToxTracker has shown improved sensitivity and specificity for the detection of known in vivo genotoxicants when compared to existing ‘standard battery’ in vitro tests. At the current time however, quantitative genotoxic potency correlations between ToxTracker and well-recognised in vivo tests are not yet available. Here we use dose–response data from the three DNA-damage-focused ToxTracker endpoints and from the in vivo micronucleus assay to carry out quantitative, genotoxic potency estimations for a range of aromatic amine and alkylating agents using the benchmark dose (BMD) approach. This strategy, using both the exponential and the Hill BMD model families, was found to produce robust, visually intuitive and similarly ordered genotoxic potency rankings for 17 compounds across the BSCL2-GFP, RTKN-GFP and BTG2-GFP ToxTracker endpoints. Eleven compounds were similarly assessed using data from the in vivo micronucleus assay. Cross-systems genotoxic potency correlations for the eight matched compounds demonstrated in vitro–in vivo correlation, albeit with marked scatter across compounds. No evidence for distinct differences in the sensitivity of the three ToxTracker endpoints was found. The presented analyses show that quantitative potency determinations from in vitro data enable more than just qualitative screening and hazard identification in genetic toxicology.
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Affiliation(s)
- John W Wills
- Biominerals Research, Cambridge University Department of Veterinary Medicine, Cambridge, UK.,Centre for Nanohealth, Swansea University College of Engineering, Swansea, UK
| | | | - Huw D Summers
- Centre for Nanohealth, Swansea University College of Engineering, Swansea, UK
| | - Paul Rees
- Centre for Nanohealth, Swansea University College of Engineering, Swansea, UK.,Broad Institute of MIT & Harvard, Cambridge, MA, USA
| | - George E Johnson
- Institute of Life Science, Swansea University Medical School, Swansea, UK
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30
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Czekala L, Chapman F, Simms L, Rudd K, Trelles Sticken E, Wieczorek R, Bode LM, Pani J, Moelijker N, Derr R, Brandsma I, Hendriks G, Stevenson M, Walele T. The in vitro ToxTracker and Aneugen Clastogen Evaluation extension assay as a tool in the assessment of relative genotoxic potential of e-liquids and their aerosols. Mutagenesis 2021; 36:129-142. [PMID: 33769537 PMCID: PMC8166346 DOI: 10.1093/mutage/geaa033] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Accepted: 11/24/2020] [Indexed: 12/14/2022] Open
Abstract
In vitro (geno)toxicity assessment of electronic vapour products (EVPs), relative to conventional cigarette, currently uses assays, including the micronucleus and Ames tests. Whilst informative on induction of a finite endpoint and relative risk posed by test articles, such assays could benefit from mechanistic supplementation. The ToxTracker and Aneugen Clastogen Evaluation analysis can indicate the activation of reporters associated with (geno)toxicity, including DNA damage, oxidative stress, the p53-related stress response and protein damage. Here, we tested for the different effects of a selection of neat e-liquids, EVP aerosols and Kentucky reference 1R6F cigarette smoke samples in the ToxTracker assay. The assay was initially validated to assess whether a mixture of e-liquid base components, propylene glycol (PG) and vegetable glycerine (VG) had interfering effects within the system. This was achieved by spiking three positive controls into the system with neat PG/VG or phosphate-buffered saline bubbled (bPBS) PG/VG aerosol (nicotine and flavour free). PG/VG did not greatly affect responses induced by the compounds. Next, when compared to cigarette smoke samples, neat e-liquids and bPBS aerosols (tobacco flavour; 1.6% freebase nicotine, 1.6% nicotine salt or 0% nicotine) exhibited reduced and less complex responses. Tested up to a 10% concentration, EVP aerosol bPBS did not induce any ToxTracker reporters. Neat e-liquids, tested up to 1%, induced oxidative stress reporters, thought to be due to their effects on osmolarity in vitro. E-liquid nicotine content did not affect responses induced. Additionally, spiking nicotine alone only induced an oxidative stress response at a supraphysiological level. In conclusion, the ToxTracker assay is a quick, informative screen for genotoxic potential and mechanisms of a variety of (compositionally complex) samples, derived from cigarettes and EVPs. This assay has the potential for future application in the assessment battery for next-generation (smoking alternative) products, including EVPs.
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Affiliation(s)
- Lukasz Czekala
- Group Science and Regulatory Affairs, Imperial Brands PLC, Bristol, UK
| | - Fiona Chapman
- Group Science and Regulatory Affairs, Imperial Brands PLC, Bristol, UK
| | - Liam Simms
- Group Science and Regulatory Affairs, Imperial Brands PLC, Bristol, UK
| | - Kathryn Rudd
- Group Science and Regulatory Affairs, Imperial Brands PLC, Bristol, UK
| | - Edgar Trelles Sticken
- Reemtsma Cigarettenfabriken GmbH, an Imperial Brands PLC Company, Albert-Einstein-Ring-7, D-22761 Hamburg, Germany
| | - Roman Wieczorek
- Reemtsma Cigarettenfabriken GmbH, an Imperial Brands PLC Company, Albert-Einstein-Ring-7, D-22761 Hamburg, Germany
| | - Lisa Maria Bode
- Reemtsma Cigarettenfabriken GmbH, an Imperial Brands PLC Company, Albert-Einstein-Ring-7, D-22761 Hamburg, Germany
| | - Jutta Pani
- Reemtsma Cigarettenfabriken GmbH, an Imperial Brands PLC Company, Albert-Einstein-Ring-7, D-22761 Hamburg, Germany
| | - Nynke Moelijker
- Toxys B.V., Robert Boyleweg 4, 2333 CG Leiden, The Netherlands
| | - Remco Derr
- Toxys B.V., Robert Boyleweg 4, 2333 CG Leiden, The Netherlands
| | - Inger Brandsma
- Toxys B.V., Robert Boyleweg 4, 2333 CG Leiden, The Netherlands
| | - Giel Hendriks
- Toxys B.V., Robert Boyleweg 4, 2333 CG Leiden, The Netherlands
| | - Matthew Stevenson
- Group Science and Regulatory Affairs, Imperial Brands PLC, Bristol, UK
| | - Tanvir Walele
- Group Science and Regulatory Affairs, Imperial Brands PLC, Bristol, UK
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31
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Boreiko CJ, Hendriks G, Derr R, Huppert M, Rossman TG. Mode of action assessment of the genotoxic properties of antimony and its compounds evaluated in the ToxTracker assay. Mutat Res 2021; 865:503333. [PMID: 33865539 DOI: 10.1016/j.mrgentox.2021.503333] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 02/05/2021] [Accepted: 02/06/2021] [Indexed: 11/18/2022]
Abstract
Antimony (Sb) and its compounds are negative in gene mutation assays in bacteria and cultured mammalian cells but positive in some assays for clastogenicity and/or DNA damage. In order to better understand the modes of action for antimony genotoxicity, we assessed reporter gene activation by antimony and antimony compounds in the new expanded ToxTracker assay. ToxTracker evaluates the activation of biomarkers for different cellular defense mechanisms using a series of green fluorescent protein reporters inserted into mouse embryonic stem cell lines. The assay responds to: 1) DNA damage and inhibition of DNA replication; 2) oxidative stress; 3) unfolded protein response (protein damage); and 4) p53-dependent cellular stress. Sb metal powder, six trivalent (Sb(III)) compounds, and five pentavalent antimony (Sb(V)) compounds were assessed. Sb powder and all six Sb(III) compounds activated oxidative stress ToxTracker reporters at non-toxic doses. Of the five Sb(V) compounds, antimony pentachloride and potassium hexahydroantimonate induced a robust oxidative stress response while sodium antimonate induced only a weak oxidative stress response. At higher concentrations (up to either 75 % toxicity or the highest dissolved concentration tested), Sb powder and all Sb(III) compounds except for antimony trichloride induced the unfolded protein response. Of the five Sb(V) compounds tested, only potassium hexahydroantimonate induced weak activation of the unfolded protein response and was also the only pentavalent compound to yield modest (30 %) cytotoxicity. None of the compounds tested activated the DNA damage/inhibition of DNA replication reporters, nor did they activate the p53-dependent response. All Sb(III) compounds, Sb powder, and three of the five Sb(V) compounds activated the oxidative stress reporters, but there was no activation of reporters associated with DNA damage and repair or p53-dependent cellular stress. The consistent activation of reporters for oxidative stress suggests this mode of action may underlie genotoxicity responses for antimony and its compounds.
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Affiliation(s)
- Craig J Boreiko
- CJB Risk Analysis, 5915 Beech Bluff Lane, Durham, NC, 27705, USA.
| | - Giel Hendriks
- Toxys B.V., Robert Boyleweg 4, 2333 CG, Leiden, The Netherlands
| | - Remco Derr
- Toxys B.V., Robert Boyleweg 4, 2333 CG, Leiden, The Netherlands
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32
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Ware RE, Dertinger SD. Absence of hydroxyurea-induced mutational effects supports higher utilisation for the treatment of sickle cell anaemia. Br J Haematol 2021; 194:252-266. [PMID: 33570176 DOI: 10.1111/bjh.17323] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 12/21/2020] [Indexed: 12/21/2022]
Abstract
Hydroxyurea (hydroxycarbamide) is approved for treating both children and adults with sickle cell anaemia (SCA). Fetal haemoglobin (HbF) induction is the primary treatment response, along with improved anaemia, reduced haemolysis, myelosuppression and decreased endothelial inflammation. Hydroxyurea has proven clinical efficacy for SCA - treatment significantly reduces disease manifestations and prolongs survival. Despite these recognised benefits, long-standing concerns regarding the risks of mutagenic and potentially carcinogenic drug exposure have hampered efforts for broad hydroxyurea use in SCA, although these are based largely on outdated experimental models and treatment experiences with myeloproliferative neoplasms. Consequently, many patients with SCA are not receiving this highly effective disease-modifying therapy. In this review, we describe the concept of genotoxicity and its laboratory measurements, summarise hydroxyurea-associated data from both preclinical and clinical studies, and discuss carcinogenic potential. The genotoxicity results clearly demonstrate that hydroxyurea does not directly bind DNA and is not mutagenic. Rather, its genotoxic effects are limited to indirect clastogenicity occurring in select cell types, and only when high dose and time thresholds are exceeded. This absence of mutagenic activity is consistent with the observed lack of any compelling carcinogenic potential. Since hydroxyurea therapy for SCA carries minimal carcinogenic risks, the current drug labelling should be modified accordingly, and prescribing practices should be broadened to allow better access and increased utilisation of this highly effective drug.
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Affiliation(s)
- Russell E Ware
- Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.,Global Health Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
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33
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Allemang A, De Abrew KN, Shan YK, Krailler JM, Pfuhler S. A comparison of classical and 21st century genotoxicity tools: A proof of concept study of 18 chemicals comparing in vitro micronucleus, ToxTracker and genomics-based methods (TGx-DDI, whole genome clustering and connectivity mapping). ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2021; 62:92-107. [PMID: 33252785 PMCID: PMC7898312 DOI: 10.1002/em.22418] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 11/24/2020] [Accepted: 11/26/2020] [Indexed: 05/06/2023]
Abstract
A key step in the risk assessment process of a substance is the assessment of its genotoxic potential. Irrespective of the industry involved, current approaches rely on combinations of two or three in vitro tests and while highly sensitive, their specificity is thought to be limited. A refined in vitro genotoxicity testing strategy with improved predictive capacity would be beneficial and "3R" friendly as it helps to avoid unnecessary in vivo follow-up testing. Here, we describe a proof of concept study evaluating a balanced set of compounds that have in vivo negative or positive outcomes, but variable in vitro data, to determine if we could differentiate between direct and indirect acting genotoxicants. Compounds were examined in TK6 cells using an approach in which the same sample was used to evaluate both early genomic markers (Affymetrix analysis 4 hr post treatment), and the genotoxic outcome (micronuclei [MN] after 24 hr). The resulting genomic data was then analyzed using the TGx-DDI biomarker, Connectivity mapping and whole genome clustering. Chemicals were also tested in the ToxTracker assay, which uses six different biomarker genes. None of the methods correctly differentiated all direct from indirect acting genotoxicants when used alone, however, the ToxTracker assay, TGx-DDI biomarker and whole genome approaches provided high predictive capacity when used in combination with the MN assay (1/18, 2/18, 1/18 missed calls). Ultimately, a "fit for purpose" combination will depend on the specific tools available to the end user, as well as considerations of the unique benefits of the individual assays.
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Affiliation(s)
- Ashley Allemang
- Global Product StewardshipThe Procter & Gamble CompanyCincinnatiOhioUSA
| | | | - Yuqing K. Shan
- Global Product StewardshipThe Procter & Gamble CompanyCincinnatiOhioUSA
| | - Jesse M. Krailler
- Data and Modeling SciencesThe Procter & Gamble CompanyCincinnatiOhioUSA
| | - Stefan Pfuhler
- Global Product StewardshipThe Procter & Gamble CompanyCincinnatiOhioUSA
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E B, N E, S B, S S, D S, M T, S M, A B, D B, D T, M G. An approach for the extract generation and toxicological assessment of tobacco-free 'modern' oral nicotine pouches. Food Chem Toxicol 2020; 145:111713. [PMID: 32998027 DOI: 10.1016/j.fct.2020.111713] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 08/24/2020] [Accepted: 08/26/2020] [Indexed: 01/06/2023]
Abstract
Tobacco-free 'modern' oral nicotine pouches (MOPs), are similar in appearance and use to Swedish-style snus, but without tobacco. There are few identified methods to create test samples for toxicologically assessment of MOPs in vitro. In this study we present a simple method for the extraction of pouch material in cell culture media, providing consistent nicotine concentration and easy in vitro assessment. A series of contemporary in vitro screening assays (viability, cell health markers, oxidative stress and genotoxicity) using human oral fibroblasts (HGF) and human lung epithelial cells (H292) were employed. Extracts were generated from LYFT and compared to snus (CRP1.1) and cigarette (1R6F) reference products. MOP and CRP1.1 extracts were generated by incubating one pouch in 20 ml of cell culture media, while 1R6F AqE was prepared by smoking 1 cigarette into 20 ml of cell culture media. 1R6F demonstrated toxicological responses in most assays; CRP1.1 had minimal to moderate effects while MOP demonstrated little or no response in all assays. This study demonstrated the generation of MOPs extracts and their toxicological evaluation using in vitro screening approaches. Future product usage, pharmacokinetics and clinical studies will further substantiate the reduced risk potential of MOPs.
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Affiliation(s)
- Bishop E
- British American Tobacco, R&D, Southampton, Hampshire, SO15 8TL, UK
| | - East N
- British American Tobacco, R&D, Southampton, Hampshire, SO15 8TL, UK
| | - Bozhilova S
- British American Tobacco, R&D, Southampton, Hampshire, SO15 8TL, UK
| | - Santopietro S
- British American Tobacco, R&D, Southampton, Hampshire, SO15 8TL, UK
| | - Smart D
- British American Tobacco, R&D, Southampton, Hampshire, SO15 8TL, UK
| | - Taylor M
- British American Tobacco, R&D, Southampton, Hampshire, SO15 8TL, UK
| | - Meredith S
- British American Tobacco, R&D, Southampton, Hampshire, SO15 8TL, UK
| | - Baxter A
- British American Tobacco, R&D, Southampton, Hampshire, SO15 8TL, UK
| | - Breheny D
- British American Tobacco, R&D, Southampton, Hampshire, SO15 8TL, UK
| | - Thorne D
- British American Tobacco, R&D, Southampton, Hampshire, SO15 8TL, UK.
| | - Gaca M
- British American Tobacco, R&D, Southampton, Hampshire, SO15 8TL, UK
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Jacobs MN, Colacci A, Corvi R, Vaccari M, Aguila MC, Corvaro M, Delrue N, Desaulniers D, Ertych N, Jacobs A, Luijten M, Madia F, Nishikawa A, Ogawa K, Ohmori K, Paparella M, Sharma AK, Vasseur P. Chemical carcinogen safety testing: OECD expert group international consensus on the development of an integrated approach for the testing and assessment of chemical non-genotoxic carcinogens. Arch Toxicol 2020; 94:2899-2923. [PMID: 32594184 PMCID: PMC7395040 DOI: 10.1007/s00204-020-02784-5] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 05/07/2020] [Indexed: 12/26/2022]
Abstract
While regulatory requirements for carcinogenicity testing of chemicals vary according to product sector and regulatory jurisdiction, the standard approach starts with a battery of genotoxicity tests (which include mutagenicity assays). If any of the in vivo genotoxicity tests are positive, a lifetime rodent cancer bioassay may be requested, but under most chemical regulations (except plant protection, biocides, pharmaceuticals), this is rare. The decision to conduct further testing based on genotoxicity test outcomes creates a regulatory gap for the identification of non-genotoxic carcinogens (NGTxC). With the objective of addressing this gap, in 2016, the Organization of Economic Cooperation and Development (OECD) established an expert group to develop an integrated approach to the testing and assessment (IATA) of NGTxC. Through that work, a definition of NGTxC in a regulatory context was agreed. Using the adverse outcome pathway (AOP) concept, various cancer models were developed, and overarching mechanisms and modes of action were identified. After further refining and structuring with respect to the common hallmarks of cancer and knowing that NGTxC act through a large variety of specific mechanisms, with cell proliferation commonly being a unifying element, it became evident that a panel of tests covering multiple biological traits will be needed to populate the IATA. Consequently, in addition to literature and database investigation, the OECD opened a call for relevant assays in 2018 to receive suggestions. Here, we report on the definition of NGTxC, on the development of the overarching NGTxC IATA, and on the development of ranking parameters to evaluate the assays. Ultimately the intent is to select the best scoring assays for integration in an NGTxC IATA to better identify carcinogens and reduce public health hazards.
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Affiliation(s)
- Miriam N Jacobs
- Centre for Radiation, Chemical and Environmental Hazards (CRCE), Public Health England, Chilton, UK.
| | - Annamaria Colacci
- Center for Environment, Prevention and Health, Regional Agency for Prevention, Environment and Energy Emilia Romagna Region (Arpae), Bologna, Italy
| | - Raffaella Corvi
- European Commission Joint Research Centre (EC JRC), Ispra, Italy
| | - Monica Vaccari
- Center for Environment, Prevention and Health, Regional Agency for Prevention, Environment and Energy Emilia Romagna Region (Arpae), Bologna, Italy
| | | | | | - Nathalie Delrue
- Organisation for Economic Cooperation and Development (OECD), Paris, France
| | | | - Norman Ertych
- German Centre for the Protection of Laboratory Animals (Bf3R), German Federal Institute for Risk Assessment, Diedersdorfer Weg 1, 12277, Berlin, Germany
| | - Abigail Jacobs
- US Food and Drug Administration (FDA), Silver Spring, MD, USA
| | - Mirjam Luijten
- National Institute for Public Health and the Environment (RIVM), Bilthoven, Netherlands
| | - Federica Madia
- European Commission Joint Research Centre (EC JRC), Ispra, Italy
| | | | - Kumiko Ogawa
- National Institute of Health Sciences, Kawasaki, Japan
| | - Kiyomi Ohmori
- Kanagawa Prefectural Institute of Public Health, Chigasaki, Japan
| | - Martin Paparella
- Division of Medical Biochemistry, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
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Brandsma I, Moelijker N, Derr R, Hendriks G. Aneugen Versus Clastogen Evaluation and Oxidative Stress-Related Mode-of-Action Assessment of Genotoxic Compounds Using the ToxTracker Reporter Assay. Toxicol Sci 2020; 177:202-213. [DOI: 10.1093/toxsci/kfaa103] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Abstract
Understanding the mode-of-action (MOA) of genotoxic compounds and differentiating between direct DNA interaction and indirect genotoxicity is crucial for their reliable safety assessment. ToxTracker is a stem cell-based reporter assay that detects activation of various cellular responses that are associated with genotoxicity and cancer. ToxTracker consists of 6 different GFP reporter cell lines that can detect the induction of DNA damage, oxidative stress, and protein damage in a single test. The assay can thereby provide insight into the MOA of compounds. Genotoxicity is detected in ToxTracker by activation of 2 independent GFP reporters. Activation of the Bscl2-GFP reporter is associated with induction of DNA adducts and subsequent inhibition of DNA replication and the Rtkn-GFP reporter is activated following the formation of DNA double-strand breaks. Here, we show that the differential activation of these 2 genotoxicity reporters could be used to further differentiate between a DNA reactive and clastogenic or a non-DNA-reactive aneugenic MOA of genotoxic compounds. For further classification of aneugenic and clastogenic compounds, the ToxTracker assay was extended with cell cycle analysis and aneuploidy assessment. The extension was validated using a selection of 16 (genotoxic) compounds with a well-established MOA. Furthermore, indirect genotoxicity related to the production of reactive oxygen species was investigated using the DNA damage and oxidative stress ToxTracker reporters in combination with different reactive oxygen species scavengers. With these new extensions, ToxTracker was able to accurately classify compounds as genotoxic or nongenotoxic and could discriminate between DNA-reactive compounds, aneugens, and indirect genotoxicity caused by oxidative stress.
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Affiliation(s)
| | | | - Remco Derr
- Toxys B.V., 2333 CG Leiden, The Netherlands
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Tian S, Cyr A, Zeise K, Bryce SM, Hall N, Bemis JC, Dertinger SD. 3Rs-friendly approach to exogenous metabolic activation that supports high-throughput genetic toxicology testing. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2020; 61:408-432. [PMID: 32039521 DOI: 10.1002/em.22361] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 01/29/2020] [Accepted: 02/05/2020] [Indexed: 06/10/2023]
Abstract
MultiFlow® DNA Damage-p53, γH2AX, Phospho-Histone H3 is a miniaturized, flow cytometry-based assay that provides genotoxic mode of action information by distinguishing clastogens, aneugens, and nongenotoxicants. Work to date has focused on the p53-competent human cell line TK6. While mammalian cell genotoxicity assays typically supply exogenous metabolic activation in the form of concentrated rat liver S9, this is a less-than-ideal approach for several reasons, including 3Rs considerations. Here, we describe our experiences with low concentration S9 and saturating co-factors which were allowed to remain in contact with cells and test chemicals for 24 continuous hours. We exposed TK6 cells in 96-well plates to each of 15 reference chemicals over a range of concentrations, both in the presence and absence of 0.25% v/v phenobarbital/β-naphthoflavone-induced rat liver S9. After 4 and 24 hr of treatment cell aliquots were added to wells of a microtiter plate containing the working detergent/stain/antibody cocktail. After a brief incubation robotic sampling was employed for walk-away flow cytometric data acquisition. PROAST benchmark dose (BMD) modeling was used to characterize the resulting dose-response curves. For each of the 8 reference pro-genotoxicants studied, relative nuclei count, γH2AX, and/or p53 biomarker BMD values were order(s) of magnitude lower for 0.25% S9 conditions compared to 0% S9. Conversely, several of the direct-acting reference chemicals exhibited appreciably lower cytotoxicity and/or genotoxicity BMD values in the presence of S9 (eg, resorcinol). These results prove the efficacy of the low concentration S9 system, and indicate that an efficient and highly scalable multiplexed assay can effectively identify chemicals that require bioactivation to exert their genotoxic effects.
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Affiliation(s)
| | - Aiyana Cyr
- Litron Laboratories, Rochester, New York
| | | | | | - Nikki Hall
- Litron Laboratories, Rochester, New York
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van der Ven LTM, Rorije E, Sprong RC, Zink D, Derr R, Hendriks G, Loo LH, Luijten M. A Case Study with Triazole Fungicides to Explore Practical Application of Next-Generation Hazard Assessment Methods for Human Health. Chem Res Toxicol 2020; 33:834-848. [PMID: 32041405 DOI: 10.1021/acs.chemrestox.9b00484] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The ongoing developments in chemical risk assessment have led to new concepts building on integration of sophisticated nonanimal models for hazard characterization. Here we explore a pragmatic approach for implementing such concepts, using a case study of three triazole fungicides, namely, flusilazole, propiconazole, and cyproconazole. The strategy applied starts with evaluating the overall level of concern by comparing exposure estimates to toxicological potential, followed by a combination of in silico tools and literature-derived high-throughput screening assays and computational elaborations to obtain insight into potential toxicological mechanisms and targets in the organism. Additionally, some targeted in vitro tests were evaluated for their utility to confirm suspected mechanisms of toxicity and to generate points of departure. Toxicological mechanisms instead of the current "end point-by-end point" approach should guide the selection of methods and assays that constitute a toolbox for next-generation risk assessment. Comparison of the obtained in silico and in vitro results with data from traditional in vivo testing revealed that, overall, nonanimal methods for hazard identification can produce adequate qualitative hazard information for risk assessment. Follow-up studies are needed to further refine the proposed approach, including the composition of the toolbox, toxicokinetics models, and models for exposure assessment.
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Pinter E, Rainer B, Czerny T, Riegel E, Schilter B, Marin-Kuan M, Tacker M. Evaluation of the Suitability of Mammalian In Vitro Assays to Assess the Genotoxic Potential of Food Contact Materials. Foods 2020; 9:foods9020237. [PMID: 32098342 PMCID: PMC7074469 DOI: 10.3390/foods9020237] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 02/12/2020] [Accepted: 02/19/2020] [Indexed: 01/25/2023] Open
Abstract
Background: Non-targeted screening of food contact materials (FCM) for non-intentionally added substances (NIAS) reveals a great number of unknown and unidentified substances present at low concentrations. In the absence of toxicological data, the application of the threshold of toxicological concern (TTC) or of EU Regulation 10/2011 requires methods able to fulfill safety threshold criteria. In this review, mammalian in vitro genotoxicity assays are analyzed for their ability to detect DNA-damaging substances at limits of biological detection (LOBD) corresponding to the appropriate safety thresholds. Results: The ability of the assays to detect genotoxic effects varies greatly between substance classes. Especially for direct-acting mutagens, the assays lacked the ability to detect most DNA reactive substances below the threshold of 10 ppb, making them unsuitable to pick up potential genotoxicants present in FCM migrates. However, suitability for the detection of chromosomal damage or investigation of other modes of action makes them a complementary tool as part of a standard test battery aimed at giving additional information to ensure safety. Conclusion: improvements are necessary to comply with regulatory thresholds to consider mammalian genotoxicity in vitro assays to assess FCM safety.
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Affiliation(s)
- Elisabeth Pinter
- Department of Applied Life Sciences, University of Applied Sciences, FH Campus Wien, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria
- Correspondence: ; Tel.: +43-1-606-6877-3584
| | - Bernhard Rainer
- Department of Applied Life Sciences, University of Applied Sciences, FH Campus Wien, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria
| | - Thomas Czerny
- Department of Applied Life Sciences, University of Applied Sciences, FH Campus Wien, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria
| | - Elisabeth Riegel
- Department of Applied Life Sciences, University of Applied Sciences, FH Campus Wien, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria
| | - Benoît Schilter
- Nestlé Research Center, Route du Jorat 57, 1000 Lausanne, Switzerland
| | | | - Manfred Tacker
- Department of Applied Life Sciences, University of Applied Sciences, FH Campus Wien, Helmut-Qualtinger-Gasse 2, 1030 Vienna, Austria
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40
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McCarrick S, Cappellini F, Kessler A, Moelijker N, Derr R, Hedberg J, Wold S, Blomberg E, Odnevall Wallinder I, Hendriks G, Karlsson HL. ToxTracker Reporter Cell Lines as a Tool for Mechanism-Based (geno)Toxicity Screening of Nanoparticles-Metals, Oxides and Quantum Dots. NANOMATERIALS 2020; 10:nano10010110. [PMID: 31935871 PMCID: PMC7023144 DOI: 10.3390/nano10010110] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 12/20/2019] [Accepted: 12/25/2019] [Indexed: 12/28/2022]
Abstract
The increased use of nanoparticles (NPs) requires efficient testing of their potential toxic effects. A promising approach is to use reporter cell lines to quickly assess the activation of cellular stress response pathways. This study aimed to use the ToxTracker reporter cell lines to investigate (geno)toxicity of various metal- or metal oxide NPs and draw general conclusions on NP-induced effects, in combination with our previous findings. The NPs tested in this study (n = 18) also included quantum dots (QDs) in different sizes. The results showed a large variation in cytotoxicity of the NPs tested. Furthermore, whereas many induced oxidative stress only few activated reporters related to DNA damage. NPs of manganese (Mn and Mn3O4) induced the most remarkable ToxTracker response with activation of reporters for oxidative stress, DNA damage, protein unfolding and p53-related stress. The QDs (CdTe) were highly toxic showing clearly size-dependent effects and calculations suggest surface area as the most relevant dose metric. Of all NPs investigated in this and previous studies the following induce the DNA damage reporter; CuO, Co, CoO, CdTe QDs, Mn, Mn3O4, V2O5, and welding NPs. We suggest that these NPs are of particular concern when considering genotoxicity induced by metal- and metal oxide NPs.
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Affiliation(s)
- Sarah McCarrick
- Institute of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Francesca Cappellini
- Institute of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Amanda Kessler
- KTH Royal Institute of Technology, Division of Surface and Corrosion Science, Department of Chemistry, 100 44 Stockholm, Sweden
| | | | | | - Jonas Hedberg
- KTH Royal Institute of Technology, Division of Surface and Corrosion Science, Department of Chemistry, 100 44 Stockholm, Sweden
| | - Susanna Wold
- KTH Royal Institute of Technology, Division of Surface and Corrosion Science, Department of Chemistry, 100 44 Stockholm, Sweden
| | - Eva Blomberg
- KTH Royal Institute of Technology, Division of Surface and Corrosion Science, Department of Chemistry, 100 44 Stockholm, Sweden
- Division Bioscience and Materials, RISE Research Institutes of Sweden, 111 21 Stockholm, Sweden
| | - Inger Odnevall Wallinder
- KTH Royal Institute of Technology, Division of Surface and Corrosion Science, Department of Chemistry, 100 44 Stockholm, Sweden
| | | | - Hanna L. Karlsson
- Institute of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
- Correspondence:
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Smart DJ, Helbling FR, Verardo M, Huber A, McHugh D, Vanscheeuwijck P. Development of an integrated assay in human TK6 cells to permit comprehensive genotoxicity analysis in vitro. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2020; 849:503129. [DOI: 10.1016/j.mrgentox.2019.503129] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 11/26/2019] [Accepted: 12/23/2019] [Indexed: 01/24/2023]
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Sasaki JC, Allemang A, Bryce SM, Custer L, Dearfield KL, Dietz Y, Elhajouji A, Escobar PA, Fornace AJ, Froetschl R, Galloway S, Hemmann U, Hendriks G, Li HH, Luijten M, Ouedraogo G, Peel L, Pfuhler S, Roberts DJ, Thybaud V, van Benthem J, Yauk CL, Schuler M. Application of the adverse outcome pathway framework to genotoxic modes of action. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2020; 61:114-134. [PMID: 31603995 DOI: 10.1002/em.22339] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 09/17/2019] [Accepted: 09/23/2019] [Indexed: 05/22/2023]
Abstract
In May 2017, the Health and Environmental Sciences Institute's Genetic Toxicology Technical Committee hosted a workshop to discuss whether mode of action (MOA) investigation is enhanced through the application of the adverse outcome pathway (AOP) framework. As AOPs are a relatively new approach in genetic toxicology, this report describes how AOPs could be harnessed to advance MOA analysis of genotoxicity pathways using five example case studies. Each of these genetic toxicology AOPs proposed for further development includes the relevant molecular initiating events, key events, and adverse outcomes (AOs), identification and/or further development of the appropriate assays to link an agent to these events, and discussion regarding the biological plausibility of the proposed AOP. A key difference between these proposed genetic toxicology AOPs versus traditional AOPs is that the AO is a genetic toxicology endpoint of potential significance in risk characterization, in contrast to an adverse state of an organism or a population. The first two detailed case studies describe provisional AOPs for aurora kinase inhibition and tubulin binding, leading to the common AO of aneuploidy. The remaining three case studies highlight provisional AOPs that lead to chromosome breakage or mutation via indirect DNA interaction (inhibition of topoisomerase II, production of cellular reactive oxygen species, and inhibition of DNA synthesis). These case studies serve as starting points for genotoxicity AOPs that could ultimately be published and utilized by the broader toxicology community and illustrate the practical considerations and evidence required to formalize such AOPs so that they may be applied to genetic toxicity evaluation schemes. Environ. Mol. Mutagen. 61:114-134, 2020. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
| | | | | | - Laura Custer
- Bristol-Myers Squibb Company, Drug Safety Evaluation, New Brunswick, New Jersey
| | | | - Yasmin Dietz
- Sanofi-Aventis Deutschland GmbH, Frankfurt, Germany
| | | | | | | | | | | | | | | | - Heng-Hong Li
- Georgetown University, Washington, District of Columbia
| | - Mirjam Luijten
- National Institute for Public Health and the Environment, Bilthoven, The Netherlands
| | | | - Lauren Peel
- Health and Environmental Sciences Institute, Washington, District of Columbia
| | | | | | - Véronique Thybaud
- Sanofi, Research and Development, Preclinical Safety, Vitry-sur-Seine, France
| | - Jan van Benthem
- National Institute for Public Health and the Environment, Bilthoven, The Netherlands
| | - Carole L Yauk
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, Canada
| | - Maik Schuler
- Pfizer Inc, World Wide Research and Development, Groton, Connecticut
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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: 1.2] [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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McCarrick S, Wei Z, Moelijker N, Derr R, Persson KA, Hendriks G, Odnevall Wallinder I, Hedberg Y, Karlsson HL. High variability in toxicity of welding fume nanoparticles from stainless steel in lung cells and reporter cell lines: the role of particle reactivity and solubility. Nanotoxicology 2019; 13:1293-1309. [PMID: 31418618 DOI: 10.1080/17435390.2019.1650972] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Millions of people in the world perform welding as their primary occupation resulting in exposure to metal-containing nanoparticles in the fumes generated. Even though health effects including airway diseases are well-known, there is currently a lack of studies investigating how different welding set-ups and conditions affect the toxicity of generated nanoparticles of the welding fume. The aim of this study was to investigate the toxicity of nine types of welding fume particles generated via active gas shielded metal arc welding (GMAW) of chromium-containing stainless steel under different conditions and, furthermore, to correlate the toxicity to the particle characteristics. Toxicological endpoints investigated were generation of reactive oxygen species (ROS), cytotoxicity, genotoxicity and activation of ToxTracker reporter cell lines. The results clearly underline that the choice of filler material has a large influence on the toxic potential. Fume particles generated by welding with the tested flux-cored wire (FCW) were found to be more cytotoxic compared to particles generated by welding with solid wire or metal-cored wire (MCW). FCW fume particles were also the most potent in causing ROS and DNA damage and they furthermore activated reporters related to DNA double- strand breaks and p53 signaling. Interestingly, the FCW fume particles were the most soluble in PBS, releasing more chromium in the hexavalent form and manganese compared to the other fumes. These results emphasize the importance of solubility of different metal constituents of the fume particles, rather than the total metal content, for their acute toxic potential.
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Affiliation(s)
- Sarah McCarrick
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Zheng Wei
- Department of Chemistry, Division of Surface and Corrosion Science, KTH Royal Institute of Technology, Stockholm, Sweden
| | | | | | | | | | - Inger Odnevall Wallinder
- Department of Chemistry, Division of Surface and Corrosion Science, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Yolanda Hedberg
- Department of Chemistry, Division of Surface and Corrosion Science, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Hanna L Karlsson
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
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45
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Bernacki DT, Bryce SM, Bemis JC, Dertinger SD. Aneugen Molecular Mechanism Assay: Proof-of-Concept With 27 Reference Chemicals. Toxicol Sci 2019; 170:382-393. [PMID: 31132080 PMCID: PMC6657583 DOI: 10.1093/toxsci/kfz123] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A tiered bioassay and data analysis scheme is described for elucidating the most common molecular targets responsible for chemical-induced in vitro aneugenicity: tubulin destabilization, tubulin stabilization, and inhibition of mitotic kinase(s). To evaluate this strategy, TK6 cells were first exposed to each of 27 presumed aneugens over a range of concentrations. After 4 and 24 h of treatment, γH2AX, p53, phospho-histone H3 (p-H3), and polyploidization biomarkers were evaluated using the MultiFlow DNA Damage Assay Kit. The assay identified 27 of 27 chemicals as genotoxic, with 25 exhibiting aneugenic signatures, 1 aneugenic and clastogenic, and 1 clastogenic. Subsequently, a newly described follow-up assay was employed to investigate the aneugenic agents' molecular targets. For these experiments, TK6 cells were exposed to each of 26 chemicals in the presence of 488 Taxol. After 4 h, cells were lysed and the liberated nuclei and mitotic chromosomes were stained with a nucleic acid dye and labeled with fluorescent antibodies against p-H3 and Ki-67. Flow cytometric analyses revealed that alterations to 488 Taxol-associated fluorescence were only observed with tubulin binders-increases in the case of tubulin stabilizers, decreases with destabilizers. Mitotic kinase inhibitors with known Aurora kinase B inhibiting activity were the only aneugens that dramatically decreased the ratio of p-H3-positive to Ki-67-positive nuclei. Unsupervised hierarchical clustering based on 488 Taxol fluorescence and p-H3: Ki-67 ratios clearly distinguished compounds with these disparate molecular mechanisms. Furthermore, a classification algorithm based on an artificial neural network was found to effectively predict molecular target, as leave-one-out cross-validation resulted in 25/26 agreement with a priori expectations. These results are encouraging, as they suggest that an adequate number of training set chemicals, in conjunction with a machine learning algorithm based on 488 Taxol, p-H3, and Ki-67 responses, can reliably elucidate the most commonly encountered aneugenic molecular targets.
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Brown DM, Danielsen PH, Derr R, Moelijker N, Fowler P, Stone V, Hendriks G, Møller P, Kermanizadeh A. The mechanism-based toxicity screening of particles with use in the food and nutrition sector via the ToxTracker reporter system. Toxicol In Vitro 2019; 61:104594. [PMID: 31279906 DOI: 10.1016/j.tiv.2019.104594] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 06/19/2019] [Accepted: 07/03/2019] [Indexed: 12/29/2022]
Abstract
The rapid expansion of the incorporation of nano-sized materials in consumer products overlaps with the necessity for high-throughput reliable screening tools for the identification of the potential hazardous properties of the nanomaterials. The ToxTracker assay (mechanism-based reporter assay based on embryonic stem cells that uses GFP-tagged biomarkers for detection of DNA damage, oxidative stress and general cellular stress) is one such tool, which could prove useful in the field of particle toxicology allowing for high throughput screening. Here, ToxTracker was utilised to evaluate the potential hazardous properties of two particulates currently used in the food industry (vegetable carbon (E153) and food-grade TiO2 (E171)). Due to the fact that ToxTracker is based on a stem cell format, it is crucial that the data generated is assessed for its suitability and comparability to more conventionally used relevant source of cells - in this case cells from the gastrointestinal tract and the liver. Therefore, the cell reporter findings were compared to data from traditional assays (cytotoxicity, anti-oxidant depletion and DNA damage) and tissue relevant cell types. The data showed E171 to be the most cytotoxic, decreased intracellular glutathione and the most significant with regards to genotoxic effects. The ToxTracker data showed comparability to conventional toxicity and oxidative stress assays; however, some discrepancies were evident between the findings from ToxTracker and the comet assay.
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Affiliation(s)
- David M Brown
- Heriot Watt University, School of Engineering and Physical Sciences, Edinburgh, UK
| | - Pernille Høgh Danielsen
- University of Copenhagen, Department of Public Health, Section of Environmental Health, Copenhagen, Denmark
| | | | | | | | - Vicki Stone
- Heriot Watt University, School of Engineering and Physical Sciences, Edinburgh, UK
| | | | - Peter Møller
- University of Copenhagen, Department of Public Health, Section of Environmental Health, Copenhagen, Denmark
| | - Ali Kermanizadeh
- Heriot Watt University, School of Engineering and Physical Sciences, Edinburgh, UK.
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Cox JA, Zwart EP, Luijten M, White PA. The development and prevalidation of an in vitro mutagenicity assay based on MutaMouse primary hepatocytes, Part II: Assay performance for the identification of mutagenic chemicals. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2019; 60:348-360. [PMID: 30714215 PMCID: PMC6593967 DOI: 10.1002/em.22277] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 01/23/2019] [Accepted: 01/29/2019] [Indexed: 06/09/2023]
Abstract
As demonstrated in Part I, cultured MutaMouse primary hepatocytes (PHs) are suitable cells for use in an in vitro gene mutation assay due to their metabolic competence, their "normal" phenotype, and the presence of the MutaMouse transgene for reliable mutation scoring. The performance of these cells in an in vitro gene mutation assay is evaluated in this study, Part II. A panel of 13 mutagenic and nonmutagenic compounds was selected to investigate the performance of the MutaMouse PH in vitro gene mutation assay. The nine mutagens represent a range of classes of chemicals and include mutagens that are both direct-acting and requiring metabolic activation. All the mutagens tested, except for ICR 191, elicited significant, concentration-dependent increases in mutant frequency (MF) ranging from 2.6- to 14.4-fold over the control. None of the four nonmutagens, including two misleading, or "false," positives (i.e., tertiary butylhydroquinone [TBHQ] and eugenol), yielded any significant increases in MF. The benchmark dose covariate approach facilitated ranking of the positive chemicals from most (i.e., 3-nitrobenzanthrone [3-NBA], benzo[a]pyrene [BaP], and aflatoxin B1 [AFB1]) to least (i.e., N-ethyl-N-nitrosourea [ENU]) potent. Overall, the results of this preliminary validation study suggest that this assay may serve as a complimentary tool alongside the standard genotoxicity test battery. This study, alongside Part I, illustrates the promise of MutaMouse PHs for use in an in vitro gene mutation assay, particularly for chemicals requiring metabolic activation. Environ. Mol. Mutagen. 60:348-360, 2019. © 2019 The Authors. Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society.
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Affiliation(s)
- Julie A. Cox
- Environmental Health Science and Research BureauHealth CanadaOttawaOntarioCanada
- Department of BiologyUniversity of OttawaOttawaOntarioCanada
| | - Edwin P. Zwart
- Centre for Health ProtectionNational Institute for Public Health and the Environment (RIVM)BilthovenThe Netherlands
| | - Mirjam Luijten
- Centre for Health ProtectionNational Institute for Public Health and the Environment (RIVM)BilthovenThe Netherlands
| | - Paul A. White
- Environmental Health Science and Research BureauHealth CanadaOttawaOntarioCanada
- Department of BiologyUniversity of OttawaOttawaOntarioCanada
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Lynch AM, Eastmond D, Elhajouji A, Froetschl R, Kirsch-Volders M, Marchetti F, Masumura K, Pacchierotti F, Schuler M, Tweats D. Targets and mechanisms of chemically induced aneuploidy. Part 1 of the report of the 2017 IWGT workgroup on assessing the risk of aneugens for carcinogenesis and hereditary diseases. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2019; 847:403025. [PMID: 31699346 DOI: 10.1016/j.mrgentox.2019.02.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 01/22/2019] [Accepted: 02/20/2019] [Indexed: 02/06/2023]
Abstract
An aneuploidy workgroup was established as part of the 7th International Workshops on Genotoxicity Testing. The workgroup conducted a review of the scientific literature on the biological mechanisms of aneuploidy in mammalian cells and methods used to detect chemical aneugens. In addition, the current regulatory framework was discussed, with the objective to arrive at consensus statements on the ramifications of exposure to chemical aneugens for human health risk assessment. As part of these efforts, the workgroup explored the use of adverse outcome pathways (AOPs) to document mechanisms of chemically induced aneuploidy in mammalian somatic cells. The group worked on two molecular initiating events (MIEs), tubulin binding and binding to the catalytic domain of aurora kinase B, which result in several adverse outcomes, including aneuploidy. The workgroup agreed that the AOP framework provides a useful approach to link evidence for MIEs with aneuploidy on a cellular level. The evidence linking chemically induced aneuploidy with carcinogenicity and hereditary disease was also reviewed and is presented in two companion papers. In addition, the group came to the consensus that the current regulatory test batteries, while not ideal, are sufficient for the identification of aneugens and human risk assessment. While it is obvious that there are many different MIEs that could lead to the induction of aneuploidy, the most commonly observed mechanisms involving chemical aneugens are related to tubulin binding and, to a lesser extent, inhibition of mitotic kinases. The comprehensive review presented here should help with the identification and risk management of aneugenic agents.
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Affiliation(s)
| | | | - Azeddine Elhajouji
- Novartis Institutes for Biomedical Research, Preclinical Safety, Basel, Switzerland
| | | | | | - Francesco Marchetti
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON, Canada
| | - Kenichi Masumura
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, Kanagawa, Japan
| | - Francesca Pacchierotti
- Health Protection Technology Division, Laboratory of Biosafety and Risk Assessment, ENEA, CR Casaccia, Rome, Italy
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Bioinspired Designs, Molecular Premise and Tools for Evaluating the Ecological Importance of Antimicrobial Peptides. Pharmaceuticals (Basel) 2018; 11:ph11030068. [PMID: 29996512 PMCID: PMC6161137 DOI: 10.3390/ph11030068] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 07/06/2018] [Accepted: 07/07/2018] [Indexed: 02/07/2023] Open
Abstract
This review article provides an overview of recent developments in antimicrobial peptides (AMPs), summarizing structural diversity, potential new applications, activity targets and microbial killing responses in general. The use of artificial and natural AMPs as templates for rational design of peptidomimetics are also discussed and some strategies are put forward to curtail cytotoxic effects against eukaryotic cells. Considering the heat-resistant nature, chemical and proteolytic stability of AMPs, we attempt to summarize their molecular targets, examine how these macromolecules may contribute to potential environmental risks vis-à-vis the activities of the peptides. We further point out the evolutional characteristics of the macromolecules and indicate how they can be useful in designing target-specific peptides. Methods are suggested that may help to assess toxic mechanisms of AMPs and possible solutions are discussed to promote the development and application of AMPs in medicine. Even if there is wide exposure to the environment like in the hospital settings, AMPs may instead contribute to prevent healthcare-associated infections so long as ecotoxicological aspects are considered.
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Cappellini F, Hedberg Y, McCarrick S, Hedberg J, Derr R, Hendriks G, Odnevall Wallinder I, Karlsson HL. Mechanistic insight into reactivity and (geno)toxicity of well-characterized nanoparticles of cobalt metal and oxides. Nanotoxicology 2018; 12:602-620. [DOI: 10.1080/17435390.2018.1470694] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
| | - Yolanda Hedberg
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
- Department of Chemistry, Division of Surface and Corrosion Science, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Sarah McCarrick
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Jonas Hedberg
- Department of Chemistry, Division of Surface and Corrosion Science, KTH Royal Institute of Technology, Stockholm, Sweden
| | | | | | - Inger Odnevall Wallinder
- Department of Chemistry, Division of Surface and Corrosion Science, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Hanna L. Karlsson
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
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