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Montalbano AM, Di Sano C, Albano GD, Gjomarkaj M, Ricciardolo FLM, Profita M. IL-17A Drives Oxidative Stress and Cell Growth in A549 Lung Epithelial Cells: Potential Protective Action of Oleuropein. Nutrients 2024; 16:2123. [PMID: 38999871 PMCID: PMC11243068 DOI: 10.3390/nu16132123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2024] [Revised: 06/29/2024] [Accepted: 07/01/2024] [Indexed: 07/14/2024] Open
Abstract
IL-17A drives inflammation and oxidative stress, affecting the progression of chronic lung diseases (asthma, chronic obstructive pulmonary disease (COPD), lung cancer, and cystic fibrosis). Oleuropein (OLP) is a polyphenolic compound present in olive oil and widely included in the Mediterranean diet. It exerts antioxidant and anti-inflammatory activities, oxidative stress resistance, and anticarcinogenic effects with a conceivable positive impact on human health. We hypothesized that OLP positively affects the mechanisms of oxidative stress, apoptosis, DNA damage, cell viability during proliferation, and cell growth in alveolar epithelial cells and tested its effect in a human alveolar epithelial cell line (A549) in the presence of IL-17A. Our results show that OLP decreases the levels of oxidative stress (Reactive Oxygen Species, Mitochondrial membrane potential) and DNA damage (H2AX phosphorylation-ser139, Olive Tail Moment data) and increases cell apoptosis in A549 cells exposed to IL-17A. Furthermore, OLP decreases the number of viable cells during proliferation, the migratory potential (Scratch test), and the single cell capacity to grow within colonies as a cancer phenotype in A549 cells exposed to IL-17A. In conclusion, we suggest that OLP might be useful to protect lung epithelial cells from oxidative stress, DNA damage, cell growth, and cell apoptosis. This effect might be exerted in lung diseases by the downregulation of IL-17A activities. Our results suggest a positive effect of the components of olive oil on human lung health.
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Affiliation(s)
- Angela Marina Montalbano
- Institute of Translational Pharmacology-National Research Council of Italy (IFT-CNR), 90146 Palermo, Italy
| | - Caterina Di Sano
- Institute of Translational Pharmacology-National Research Council of Italy (IFT-CNR), 90146 Palermo, Italy
| | - Giusy Daniela Albano
- Institute of Translational Pharmacology-National Research Council of Italy (IFT-CNR), 90146 Palermo, Italy
| | - Mark Gjomarkaj
- Institute of Translational Pharmacology-National Research Council of Italy (IFT-CNR), 90146 Palermo, Italy
| | - Fabio Luigi Massimo Ricciardolo
- Institute of Translational Pharmacology-National Research Council of Italy (IFT-CNR), 90146 Palermo, Italy
- Department of Clinical and Biological Sciences, University of Turin, 10043 Turin, Italy
| | - Mirella Profita
- Institute of Translational Pharmacology-National Research Council of Italy (IFT-CNR), 90146 Palermo, Italy
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2
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Buick JK, Rowan-Carroll A, Gagné R, Williams A, Chen R, Li HH, Fornace AJ, Chao C, Engelward BP, Frötschl R, Ellinger-Ziegelbauer H, Pettit SD, Aubrecht J, Yauk CL. Integrated Genotoxicity Testing of three anti-infective drugs using the TGx-DDI transcriptomic biomarker and high-throughput CometChip® assay in TK6 cells. FRONTIERS IN TOXICOLOGY 2022; 4:991590. [PMID: 36211197 PMCID: PMC9540394 DOI: 10.3389/ftox.2022.991590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 08/10/2022] [Indexed: 11/21/2022] Open
Abstract
Genotoxicity testing relies on the detection of gene mutations and chromosome damage and has been used in the genetic safety assessment of drugs and chemicals for decades. However, the results of standard genotoxicity tests are often difficult to interpret due to lack of mode of action information. The TGx-DDI transcriptomic biomarker provides mechanistic information on the DNA damage-inducing (DDI) capability of chemicals to aid in the interpretation of positive in vitro genotoxicity data. The CometChip® assay was developed to assess DNA strand breaks in a higher-throughput format. We paired the TGx-DDI biomarker with the CometChip® assay in TK6 cells to evaluate three model agents: nitrofurantoin (NIT), metronidazole (MTZ), and novobiocin (NOV). TGx-DDI was analyzed by two independent labs and technologies (nCounter® and TempO-Seq®). Although these anti-infective drugs are, or have been, used in human and/or veterinary medicine, the standard genotoxicity testing battery showed significant genetic safety findings. Specifically, NIT is a mutagen and causes chromosome damage, and MTZ and NOV cause chromosome damage in conventional in vitro tests. Herein, the TGx-DDI biomarker classified NIT and MTZ as non-DDI at all concentrations tested, suggesting that NIT’s mutagenic activity is bacterial specific and that the observed chromosome damage by MTZ might be a consequence of in vitro test conditions. In contrast, NOV was classified as DDI at the second highest concentration tested, which is in line with the fact that NOV is a bacterial DNA-gyrase inhibitor that also affects topoisomerase II at high concentrations. The lack of DNA damage for NIT and MTZ was confirmed by the CometChip® results, which were negative for all three drugs except at overtly cytotoxic concentrations. This case study demonstrates the utility of combining the TGx-DDI biomarker and CometChip® to resolve conflicting genotoxicity data and provides further validation to support the reproducibility of the biomarker.
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Affiliation(s)
- Julie K. Buick
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON, Canada
| | - Andrea Rowan-Carroll
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON, Canada
| | - Rémi Gagné
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON, Canada
| | - Andrew Williams
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON, Canada
| | - Renxiang Chen
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, United States
- Department of Biochemistry and Molecular and Cellular Biology, Georgetown University, Washington, DC, United States
| | - Heng-Hong Li
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, United States
- Department of Biochemistry and Molecular and Cellular Biology, Georgetown University, Washington, DC, United States
| | - Albert J. Fornace
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, United States
- Department of Biochemistry and Molecular and Cellular Biology, Georgetown University, Washington, DC, United States
| | - Christy Chao
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Bevin P. Engelward
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Roland Frötschl
- Federal Institute for Drugs and Medical Devices (BfArM), Bonn, Germany
| | | | - Syril D. Pettit
- Health and Environmental Sciences Institute, Washington, DC, United States
| | - Jiri Aubrecht
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, United States
| | - Carole L. Yauk
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON, Canada
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
- *Correspondence: Carole L. Yauk,
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3
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Buick JK, Williams A, Meier MJ, Swartz CD, Recio L, Gagné R, Ferguson SS, Engelward BP, Yauk CL. A Modern Genotoxicity Testing Paradigm: Integration of the High-Throughput CometChip® and the TGx-DDI Transcriptomic Biomarker in Human HepaRG™ Cell Cultures. Front Public Health 2021; 9:694834. [PMID: 34485225 PMCID: PMC8416458 DOI: 10.3389/fpubh.2021.694834] [Citation(s) in RCA: 147] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 07/14/2021] [Indexed: 12/14/2022] Open
Abstract
Higher-throughput, mode-of-action-based assays provide a valuable approach to expedite chemical evaluation for human health risk assessment. In this study, we combined the high-throughput alkaline DNA damage-sensing CometChip® assay with the TGx-DDI transcriptomic biomarker (DDI = DNA damage-inducing) using high-throughput TempO-Seq®, as an integrated genotoxicity testing approach. We used metabolically competent differentiated human HepaRG™ cell cultures to enable the identification of chemicals that require bioactivation to cause genotoxicity. We studied 12 chemicals (nine DDI, three non-DDI) in increasing concentrations to measure and classify chemicals based on their ability to damage DNA. The CometChip® classified 10/12 test chemicals correctly, missing a positive DDI call for aflatoxin B1 and propyl gallate. The poor detection of aflatoxin B1 adducts is consistent with the insensitivity of the standard alkaline comet assay to bulky lesions (a shortcoming that can be overcome by trapping repair intermediates). The TGx-DDI biomarker accurately classified 10/12 agents. TGx-DDI correctly identified aflatoxin B1 as DDI, demonstrating efficacy for combined used of these complementary methodologies. Zidovudine, a known DDI chemical, was misclassified as it inhibits transcription, which prevents measurable changes in gene expression. Eugenol, a non-DDI chemical known to render misleading positive results at high concentrations, was classified as DDI at the highest concentration tested. When combined, the CometChip® assay and the TGx-DDI biomarker were 100% accurate in identifying chemicals that induce DNA damage. Quantitative benchmark concentration (BMC) modeling was applied to evaluate chemical potencies for both assays. The BMCs for the CometChip® assay and the TGx-DDI biomarker were highly concordant (within 4-fold) and resulted in identical potency rankings. These results demonstrate that these two assays can be integrated for efficient identification and potency ranking of DNA damaging agents in HepaRG™ cell cultures.
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Affiliation(s)
- Julie K Buick
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON, Canada
| | - Andrew Williams
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON, Canada
| | - Matthew J Meier
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON, Canada
| | - Carol D Swartz
- Integrated Laboratory Systems Inc. (ILS), Research Triangle Park, Durham, NC, United States
| | - Leslie Recio
- Integrated Laboratory Systems Inc. (ILS), Research Triangle Park, Durham, NC, United States
| | - Rémi Gagné
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON, Canada
| | - Stephen S Ferguson
- National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, Durham, NC, United States
| | - Bevin P Engelward
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Carole L Yauk
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON, Canada.,Department of Biology, University of Ottawa, Ottawa, ON, Canada
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Kidd D, Phillips S, Chirom T, Mason N, Smith R, Saul J, Whitwell J, Clements J. The 3D reconstructed skin micronucleus assay: considerations for optimal protocol design. Mutagenesis 2021; 36:37-49. [PMID: 31793640 DOI: 10.1093/mutage/gez037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 10/17/2019] [Indexed: 11/13/2022] Open
Abstract
Implementation of the seventh amendment to the EU Cosmetics Directive has driven much research into suitable in vitro alternative assays to support satisfactory risk assessments. One such assay is the reconstructed skin micronucleus (RSMN) assay. First reported in 2006, further development occurred and a standard protocol was published in 2011. To evaluate and optimise the assay at Covance Laboratories, we tested nine chemicals [4-nitrophenol (4-NP), cyclohexanone (CH), 2-ethyl-1,3-hexanediol (2-EHD), methyl methansulfonate (MMS), mitomycin C (MMC), ethyl nitrosourea (ENU), benzo[a]pyrene (BaP), cyclophosphamide (CPA) and vinblastine (VIN)] using the EpiDerm™ 3D skin model (MatTek Corporation®, IVLSL, Bratislava, Slovakia) and compared the data using the standard 48-h treatment regimen and also an emerging 72-h treatment protocol. The EpiDerm™ tissue has reportedly some metabolic capacity but data using 48-h treatments has provided mixed results. Our investigations demonstrate that the two chemicals requiring metabolic activation (BaP and CPA) were negative following the 48-h protocol but were clearly positive following 72-h treatment. Furthermore, Replication Index (RI) data showed higher RI values in vehicle control treatments (indicating increased cell division) across the treatment set following 72-h treatments. A general greater magnitude of micronucleus (MN) induction was also observed following test chemical treatment. These data suggest that the 72-h treatment protocol is more suitable as a standard approach for the detection of clastogenic, aneugenic and metabolically activated chemicals in the RSMN assay. For further assay optimisation, we compare the statistical power of scoring cells from duplicate or triplicate cultures per treatment concentration and provide recommendations.
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Affiliation(s)
- Darren Kidd
- Covance Laboratories Ltd, Otley Road, Harrogate, North Yorkshire, HG3 1PY, UK
| | - Sarah Phillips
- Covance Laboratories Ltd, Otley Road, Harrogate, North Yorkshire, HG3 1PY, UK
| | - Teresa Chirom
- Covance Laboratories Ltd, Otley Road, Harrogate, North Yorkshire, HG3 1PY, UK
| | - Nicky Mason
- Covance Laboratories Ltd, Otley Road, Harrogate, North Yorkshire, HG3 1PY, UK
| | - Robert Smith
- Covance Laboratories Ltd, Otley Road, Harrogate, North Yorkshire, HG3 1PY, UK
| | - Jim Saul
- Covance Laboratories Ltd, Otley Road, Harrogate, North Yorkshire, HG3 1PY, UK
| | - James Whitwell
- Covance Laboratories Ltd, Otley Road, Harrogate, North Yorkshire, HG3 1PY, UK
| | - Julie Clements
- Covance Laboratories Ltd, Otley Road, Harrogate, North Yorkshire, HG3 1PY, UK
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5
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Montalbano AM, Albano GD, Anzalone G, Moscato M, Gagliardo R, Di Sano C, Bonanno A, Ruggieri S, Cibella F, Profita M. Cytotoxic and genotoxic effects of the flame retardants (PBDE-47, PBDE-99 and PBDE-209) in human bronchial epithelial cells. CHEMOSPHERE 2020; 245:125600. [PMID: 31864052 DOI: 10.1016/j.chemosphere.2019.125600] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 12/03/2019] [Accepted: 12/09/2019] [Indexed: 06/10/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs) are widespread as flame-retardants in different types of consumer products. PBDEs present in the air or dust and their inhalation can damage human health by influencing the respiratory system. We evaluated the effects of environment relevant concentrations (0.01-1 μM) of PBDE-47, PBDE-99 and PBDE-209 on the mechanism of oxidative stress, dysregulation of cell proliferation, apoptosis, and DNA damage and repair (in term of H2AX phosphorylation ser139) in an in-vitro/ex-vivo model of bronchial epithelial cells. PBDEs (-47, -99 and -209) at the environment relevant concentrations (0.01 and 1 μM) induce oxidative stress (in term of NOX-4 expression as well as ROS and JC-1 production), activate the mechanism of DNA-damage and repair affecting Olive Tail length (comet assay) production and H2AX phosphorylation (ser139) in normal human bronchial epithelial cells. Furthermore PBDEs, although do not affect cell viability, induce cell apoptosis and single cell capacity to grow into a colony (like a cancer phenotype) in bronchial epithelial cells. Finally, PBDE-47 had a greater effect than -99 and -209. PBDE-47, -99 and -209 congeners exert cytotoxic and genotoxic effects, and play a critical role in the dysregulation of oxidative stress, damaging DNA and the related gene expression in bronchial epithelial cells. Our findings might suggest that PBDEs inhalation might have adverse effect on human health regarding pulmonary diseases in the areas of environmental pollution.
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Affiliation(s)
- Angela Marina Montalbano
- Institute for Research and Biomedical Innovation (IRIB), National Research Council of Italy (CNR), Palermo, Italy
| | - Giusy Daniela Albano
- Institute for Research and Biomedical Innovation (IRIB), National Research Council of Italy (CNR), Palermo, Italy
| | - Giulia Anzalone
- Institute for Research and Biomedical Innovation (IRIB), National Research Council of Italy (CNR), Palermo, Italy
| | - Monica Moscato
- Institute for Research and Biomedical Innovation (IRIB), National Research Council of Italy (CNR), Palermo, Italy
| | - Rosalia Gagliardo
- Institute for Research and Biomedical Innovation (IRIB), National Research Council of Italy (CNR), Palermo, Italy
| | - Caterina Di Sano
- Institute for Research and Biomedical Innovation (IRIB), National Research Council of Italy (CNR), Palermo, Italy
| | - Anna Bonanno
- Institute for Research and Biomedical Innovation (IRIB), National Research Council of Italy (CNR), Palermo, Italy
| | - Silvia Ruggieri
- Institute for Research and Biomedical Innovation (IRIB), National Research Council of Italy (CNR), Palermo, Italy
| | - Fabio Cibella
- Institute for Research and Biomedical Innovation (IRIB), National Research Council of Italy (CNR), Palermo, Italy
| | - Mirella Profita
- Institute for Research and Biomedical Innovation (IRIB), National Research Council of Italy (CNR), Palermo, Italy.
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6
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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: 2.0] [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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7
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Ji Z, Settivari RS, LeBaron MJ. Pilot studies evaluating the nongenotoxic rodent carcinogens phenobarbital and clofibrate in the rat Pig-a assay. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2019; 60:42-46. [PMID: 30338550 DOI: 10.1002/em.22232] [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: 06/08/2018] [Revised: 07/16/2018] [Accepted: 07/17/2018] [Indexed: 06/08/2023]
Abstract
The Pig-a assay is an emerging and promising in vivo method to determine mutagenic potential of chemicals. Since its development in 2008, remarkable progress has been made in harmonizing and characterizing the test procedures, primarily using known mutagenic chemicals. The purpose of the present study was to evaluate specificity of the Pig-a assay using two nongenotoxic and well-characterized rodent liver carcinogens, phenobarbital and clofibrate, in male F344/DuCrl rats. Daily oral administration of phenobarbital or clofibrate at established hepatotoxic doses for 28 days resulted in substantial hepatic alterations, however, did not increase the frequency of Pig-a mutation markers (RETCD59- and RBCCD59- ) compared to vehicle control or pre-exposure (Day -5) mutant frequencies. These results are consistent with the existing literature on the nonmutagenic mode of action (MoA) of phenobarbital and clofibrate liver tumors. The present study contributes to the limited, but expanding evidence on the specificity of the Pig-a assay and further for the investigations of carcinogenic MoAs, i.e., mutagenic or nonmutagenic potential of chemicals. Environ. Mol. Mutagen. 60:42-46, 2019. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Zhiying Ji
- Toxicology and Environmental Research and Consulting, The Dow Chemical Company, Midland, Michigan
| | - Raja S Settivari
- Toxicology and Environmental Research and Consulting, The Dow Chemical Company, Midland, Michigan
| | - Matthew J LeBaron
- Toxicology and Environmental Research and Consulting, The Dow Chemical Company, Midland, Michigan
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8
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Ji Z, LeBaron MJ. Applying the erythrocyte Pig-a assay concept to rat epididymal sperm for germ cell mutagenicity evaluation. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2017; 58:485-493. [PMID: 28714084 DOI: 10.1002/em.22109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Revised: 05/18/2017] [Accepted: 05/18/2017] [Indexed: 06/07/2023]
Abstract
The Pig-a assay, a recently developed in vivo somatic gene mutation assay, is based on the identification of mutant erythrocytes that have an altered repertoire of glycosylphosphatidylinositol (GPI)-anchored cell surface markers. We hypothesized that the erythrocyte Pig-a assay concept could be applied to rat cauda epididymal spermatozoa (sperm) for germ cell mutagenicity evaluation. We used GPI-anchored CD59 as the Pig-a mutation marker and examined the frequency of CD59-negative sperm using flow cytometry. A reconstruction experiment that spiked un-labeled sperm (mutant-mimic) into labeled sperm at specific ratios yielded good agreement between the detected and expected frequencies of mutant-mimic sperm, demonstrating the analytical ability for CD59-negative sperm detection. Furthermore, this methodology was assessed in F344/DuCrl rats administered N-ethyl-N-nitrosourea (ENU), a prototypical mutagen, or clofibrate, a lipid-lowering drug. Rats treated with 1, 10, or 20 mg/kg body weight/day (mkd) ENU via daily oral garage for five consecutive days showed a dose-dependent increase in the frequency of CD59-negative sperm on study day 63 (i.e., 58 days after the last ENU dose). This ENU dosing regimen also increased the frequency of CD59-negative erythrocytes. In rats treated with 300 mkd clofibrate via daily oral garage for consecutive 28 days, no treatment-related changes were detected in the frequency of CD59-negative sperm on study day 85 (i.e., 57 days after the last dose) or in the frequency of CD59-negative erythrocytes on study day 29. In conclusion, these data suggest that the epidiymal sperm Pig-a assay in rats is a promising method for evaluating germ cell mutagenicity. Environ. Mol. Mutagen. 58:485-493, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Zhiying Ji
- Toxicology and Environmental Research and Consulting, The Dow Chemical Company, Midland, Michigan, 48674
| | - Matthew J LeBaron
- Toxicology and Environmental Research and Consulting, The Dow Chemical Company, Midland, Michigan, 48674
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9
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Standley M, Allen J, Cervantes L, Lilly J, Camps M. Fluorescence-Based Reporters for Detection of Mutagenesis in E. coli. Methods Enzymol 2017. [PMID: 28645368 DOI: 10.1016/bs.mie.2017.03.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Mutagenesis in model organisms following exposure to chemicals is used as an indicator of genotoxicity. Mutagenesis assays are also used to study mechanisms of DNA homeostasis. This chapter focuses on detection of mutagenesis in prokaryotes, which boils down to two approaches: reporter inactivation (forward mutation assay) and reversion of an inactivating mutation (reversion mutation assay). Both methods are labor intensive, involving visual screening, quantification of colonies on solid media, or determining a Poisson distribution in liquid culture. Here, we present two reversion reporters for in vivo mutagenesis that produce a quantitative output, and thus have the potential to greatly reduce the amount of test chemical and labor involved in these assays. This output is obtained by coupling a TEM β lactamase-based reversion assay with GFP fluorescence, either by placing the two genes on the same plasmid or by fusing them translationally and interrupting the N-terminus of the chimeric ORF with a stop codon. We also describe a reporter aimed at facilitating the monitoring of continuous mutagenesis in mutator strains. This reporter couples two reversion markers, allowing the temporal separation of mutation events in time, thus providing information about the dynamics of mutagenesis in mutator strains. Here, we describe these reporter systems, provide protocols for use, and demonstrate their key functional features using error-prone Pol I mutagenesis as a source of mutations.
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Affiliation(s)
- Melissa Standley
- University of California-Santa Cruz, Santa Cruz, CA, United States
| | - Jennifer Allen
- University of California-Santa Cruz, Santa Cruz, CA, United States
| | - Layla Cervantes
- University of California-Santa Cruz, Santa Cruz, CA, United States
| | - Joshua Lilly
- University of California-Santa Cruz, Santa Cruz, CA, United States
| | - Manel Camps
- University of California-Santa Cruz, Santa Cruz, CA, United States.
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10
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Hvastkovs EG, Rusling JF. Modern Approaches to Chemical Toxicity Screening. CURRENT OPINION IN ELECTROCHEMISTRY 2017; 3:18-22. [PMID: 29250606 PMCID: PMC5729768 DOI: 10.1016/j.coelec.2017.03.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Chemical toxicity has a serious impact on public health, and toxicity failures of drug candidates drive up drug development costs. Many in vitro bioassays exist for toxicity screening, and newer versions of these tend to be high throughput or high content assays, some of which rely on electrochemical detection. Toxicity very often results from metabolites of the chemicals we are exposed to, so it is important that assays feature metabolic conversion. Combining bioassays, computational predictions, and accurate chemical pathway elucidation presents our best chance for reliable toxicity prediction. Employing electrochemical and electrochemiluminescent approaches, cell-free microfluidic arrays can measure relative rates of formation of DNA-metabolite adduct formation (a measure of genotoxicity) as well as DNA oxidation levels resulting from enzyme-generated metabolites. Enzymes for several organ types can be studied simultaneously. These arrays can be used to identify the most reactive metabolites, and subsequent mechanistic details can then be investigated with high throughput LC-HPLC using enzyme/DNA-coated magnetic beads.
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Affiliation(s)
- Eli G Hvastkovs
- Department of Chemistry, East Carolina University, Greenville, NC 27858, USA
| | - James F Rusling
- Department of Chemistry, University of Connecticut, Storrs, CT 06269, USA
- Institute of Material Science, University of Connecticut, Storrs, CT 06269, USA
- Department of Surgery and Neag Cancer Center, University of Connecticut Health Center, Farmington, CT 06032, USA
- School of Chemistry, National University of Ireland at Galway, Ireland
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Current nonclinical testing paradigms in support of safe clinical trials: An IQ Consortium DruSafe perspective. Regul Toxicol Pharmacol 2017; 87 Suppl 3:S1-S15. [PMID: 28483710 DOI: 10.1016/j.yrtph.2017.05.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 05/03/2017] [Accepted: 05/04/2017] [Indexed: 12/18/2022]
Abstract
The transition from nonclinical to First-in-Human (FIH) testing is one of the most challenging steps in drug development. In response to serious outcomes in a recent Phase 1 trial (sponsored by Bial), IQ Consortium/DruSafe member companies reviewed their nonclinical approach to progress small molecules safely to FIH trials. As a common practice, safety evaluation begins with target selection and continues through iterative in silico and in vitro screening to identify molecules with increased probability of acceptable in vivo safety profiles. High attrition routinely occurs during this phase. In vivo exploratory and pivotal FIH-enabling toxicity studies are then conducted to identify molecules with a favorable benefit-risk profile for humans. The recent serious incident has reemphasized the importance of nonclinical testing plans that are customized to the target, the molecule, and the intended clinical plan. Despite the challenges and inherent risks of transitioning from nonclinical to clinical testing, Phase 1 studies have a remarkably good safety record. Given the rapid scientific evolution of safety evaluation, testing paradigms and regulatory guidance must evolve with emerging science. The authors posit that the practices described herein, together with science-based risk assessment and management, support safe FIH trials while advancing development of important new medicines.
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12
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Severin I, Souton E, Dahbi L, Chagnon MC. Use of bioassays to assess hazard of food contact material extracts: State of the art. Food Chem Toxicol 2017; 105:429-447. [PMID: 28476634 DOI: 10.1016/j.fct.2017.04.046] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Revised: 04/10/2017] [Accepted: 04/29/2017] [Indexed: 01/17/2023]
Abstract
This review focuses on the use of in vitro bioassays for the hazard assessment of food contact materials (FCM) as a relevant strategy, in complement to analytical methods. FCM may transfer constituents to foods, not always detected by analytical chemistry, resulting in low but measurable human exposures. Testing FCM extracts with bioassays represents the biological response of a combination of substances, able to be released from the finished materials. Furthermore, this approach is particularly useful regarding the current risk assessment challenges with unpredicted/unidentified non-intentionally added substances (NIAS) that can be leached from the FCM in the food. Bioassays applied to assess hazard of different FCM types are described for, to date, the toxicological endpoints able to be expressed at low levels; cytotoxicity, genotoxicity and endocrine disruption potential. The bioassay strengths and relative key points needed to correctly use and improve the performance of bioassays for an additional FCM risk assessment is developed. This review compiles studies showing that combining both chemical and toxicological analyses presents a very promising and pragmatic tool for identifying new undesirable NIAS (not predicted) which can represent a great part of the migrating substances and/or "cocktail effect".
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Affiliation(s)
- Isabelle Severin
- Derttech « Packtox », University of Bourgogne Franche-Comté, INSERM LNC UMR 1231, AgroSupDijon, F-21000 Dijon, France
| | - Emilie Souton
- Derttech « Packtox », University of Bourgogne Franche-Comté, INSERM LNC UMR 1231, AgroSupDijon, F-21000 Dijon, France
| | - Laurence Dahbi
- Derttech « Packtox », University of Bourgogne Franche-Comté, INSERM LNC UMR 1231, AgroSupDijon, F-21000 Dijon, France
| | - Marie Christine Chagnon
- Derttech « Packtox », University of Bourgogne Franche-Comté, INSERM LNC UMR 1231, AgroSupDijon, F-21000 Dijon, France.
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13
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Raschke M, Igl BW, Kenny J, Collins J, Dertinger SD, Labash C, Bhalli JA, Tebbe CCM, McNeil KM, Sutter A. In Vivo Pig-a gene mutation assay: Guidance for 3Rs-friendly implementation. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2016; 57:678-686. [PMID: 27770464 DOI: 10.1002/em.22060] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 09/15/2016] [Indexed: 06/06/2023]
Abstract
The rodent Pig-a assay is an in vivo method for the detection of gene mutation, where lack of glycosylphosphatidylinositol-anchored proteins on the surface of circulating red blood cells (RBCs) serves as a reporter for Pig-a gene mutation. In the case of rats, the frequency of mutant phenotype RBCs is measured via fluorescent anti-CD59 antibodies and flow cytometry. The Pig-a assay meets the growing expectations for novel approaches in animal experimentation not only focusing on the scientific value of the assay but also on animal welfare aspects (3Rs principles), for example, amenable to integration into pivotal rodent 28-day general toxicology studies. However, as recommended in the Organisation for Economic Co-operation and Development Test Guidelines for genotoxicity testing, laboratories are expected to demonstrate their proficiency. While this has historically involved the extensive use of animals, here we describe an alternative approach based on a series of blood dilutions covering a range of mutant frequencies. The experiments described herein utilized either non-fluorescent anti-CD59 antibodies to provide elevated numbers of mutant-like cells, or a low volume blood sample from a single N-ethyl-N-nitrosourea treated animal. Results from these so-called reconstruction experiments from four independent laboratories showed good overall precision (correlation coefficients: 0.9979-0.9999) and accuracy (estimated slope: 0.71-1.09) of mutant cell scoring, which was further confirmed by Bland-Altman analysis. These data strongly support the use of reconstruction experiments for training purposes and demonstrating laboratory proficiency with very few animals, an ideal situation given the typically conflicting goals of demonstrating laboratory proficiency and reducing the use of animals. Environ. Mol. Mutagen. 57:678-686, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Marian Raschke
- Bayer Pharma AG, Muellerstrasse 178, Berlin, 13353, Germany
| | - Bernd-W Igl
- Bayer Pharma AG, Muellerstrasse 178, Berlin, 13353, Germany
| | - Julia Kenny
- GlaxoSmithKline, Park Road, Ware, Hertfordshire, SG12 0DP, United Kingdom
| | - Joanne Collins
- GlaxoSmithKline, Park Road, Ware, Hertfordshire, SG12 0DP, United Kingdom
| | | | - Carson Labash
- Litron Laboratories, 3500 Winton Place, Rochester, New York, 14623
| | - Javed A Bhalli
- Covance Laboratories Inc, 671 S. Meridian Rd, Greenfield, Indiana, 46140
| | - Cameron C M Tebbe
- Covance Laboratories Inc, 671 S. Meridian Rd, Greenfield, Indiana, 46140
| | - Kylie M McNeil
- Covance Laboratories Inc, 671 S. Meridian Rd, Greenfield, Indiana, 46140
| | - Andreas Sutter
- Bayer Pharma AG, Muellerstrasse 178, Berlin, 13353, Germany
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14
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Kuncová G, Ishizaki T, Solovyev A, Trögl J, Ripp S. The Repetitive Detection of Toluene with Bioluminescence Bioreporter Pseudomonas putida TVA8 Encapsulated in Silica Hydrogel on an Optical Fiber. MATERIALS 2016; 9:ma9060467. [PMID: 28773598 PMCID: PMC5456779 DOI: 10.3390/ma9060467] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 06/02/2016] [Accepted: 06/07/2016] [Indexed: 12/20/2022]
Abstract
Living cells of the lux-based bioluminescent bioreporter Pseudomonas putida TVA8 were encapsulated in a silica hydrogel attached to the distal wider end of a tapered quartz fiber. Bioluminescence of immobilized cells was induced with toluene at high (26.5 mg/L) and low (5.3 mg/L) concentrations. Initial bioluminescence maxima were achieved after >12 h. One week after immobilization, a biofilm-like layer of cells had formed on the surface of the silica gel. This resulted in shorter response times and more intensive bioluminescence maxima that appeared as rapidly as 2 h after toluene induction. Considerable second bioluminescence maxima were observed after inductions with 26.5 mg toluene/L. The second and third week after immobilization the biosensor repetitively and semiquantitatively detected toluene in buffered medium. Due to silica gel dissolution and biofilm detachment, the bioluminescent signal was decreasing 20-32 days after immobilization and completely extinguished after 32 days. The reproducible formation of a surface cell layer on the wider end of the tapered optical fiber can be translated to various whole cell bioluminescent biosensor devices and may serve as a platform for in-situ sensors.
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Affiliation(s)
- Gabriela Kuncová
- Institute of Chemical Process Fundamentals of the CAS, v.v.i., Rozvojová 135, 16500 Praha 6, Czech Republic.
| | - Takayuki Ishizaki
- Institute of Chemical Process Fundamentals of the CAS, v.v.i., Rozvojová 135, 16500 Praha 6, Czech Republic.
| | - Andrey Solovyev
- Institute of Chemical Process Fundamentals of the CAS, v.v.i., Rozvojová 135, 16500 Praha 6, Czech Republic.
| | - Josef Trögl
- Faculty of Environment, Jan Evangelista Purkyně University in Ústí nad Labem, Králova Výšina 3132/7, 40096 Ústí nad Labem, Czech Republic.
| | - Steven Ripp
- Center for Environmental Biotechnology, The University of Tennessee, 676 Dabney Hall, Knoxville, TN 37996, USA.
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15
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Abstract
Routine in vitro bioassays and animal toxicity studies of drug and environmental chemical candidates fail to reveal toxicity in ∼30% of cases. This Feature article addresses research on new approaches to in vitro toxicity testing as well as our own efforts to produce high-throughput genotoxicity arrays and LC-MS/MS approaches to reveal possible chemical pathways of toxicity.
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Affiliation(s)
- Eli G. Hvastkovs
- Department of Chemistry, East Carolina University Greenville, North Carolina 27858, United States
| | - James F. Rusling
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
- Department of Surgery and Neag Cancer Center, University of Connecticut Health Center, Farmington, Connecticut 06032, United States
- Institute of Material Science, University of Connecticut, Storrs, Connecticut 06269, United States
- School of Chemistry, National University of Ireland at Galway, Galway, Ireland
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16
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Hendriks G, Derr RS, Misovic B, Morolli B, Calléja FMGR, Vrieling H. The Extended ToxTracker Assay Discriminates Between Induction of DNA Damage, Oxidative Stress, and Protein Misfolding. Toxicol Sci 2016; 150:190-203. [PMID: 26719371 PMCID: PMC5009621 DOI: 10.1093/toxsci/kfv323] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Chemical exposure of cells may damage biomolecules, cellular structures, and organelles thereby jeopardizing cellular homeostasis. A multitude of defense mechanisms have evolved that can recognize specific types of damaged molecules and will initiate distinct cellular programs aiming to remove the damage inflicted and prevent cellular havoc. As a consequence, quantitative assessment of the activity of the cellular stress responses may serve as a sensitive reporter for the induction of specific types of damage. We have previously developed the ToxTracker assay, a mammalian stem cell-based genotoxicity assay employing two green fluorescent protein reporters specific for DNA damage and oxidative stress. We have now expanded the ToxTracker assay with an additional four reporter cell lines to include monitoring of additional stress signaling pathways. This panel of six green fluorescent protein reporters is able to discriminate between different primary reactivity of chemicals being their ability to react with DNA and block DNA replication, induce oxidative stress, activate the unfolded protein response, or cause a general P53-dependent cellular stress response. Extensive validation using the compound library suggested by the European Centre for the Validation of Alternative Methods (ECVAM) and a large panel of reference chemicals shows that the ToxTracker assay has an outstanding sensitivity and specificity. In addition, we developed Toxplot, a dedicated software tool for automated data analysis and graphical representation of the test results. Rapid and reliable identification by the ToxTracker assay of specific biological reactivity can significantly improve in vitro human hazard assessment of chemicals.
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Affiliation(s)
- Giel Hendriks
- Department of Human Genetics, Leiden University Medical Center, 2300RC Leiden, The Netherlands
| | - Remco S Derr
- Department of Human Genetics, Leiden University Medical Center, 2300RC Leiden, The Netherlands
| | - Branislav Misovic
- Department of Human Genetics, Leiden University Medical Center, 2300RC Leiden, The Netherlands
| | - Bruno Morolli
- Department of Human Genetics, Leiden University Medical Center, 2300RC Leiden, The Netherlands
| | - Fabienne M G R Calléja
- Department of Human Genetics, Leiden University Medical Center, 2300RC Leiden, The Netherlands
| | - Harry Vrieling
- Department of Human Genetics, Leiden University Medical Center, 2300RC Leiden, The Netherlands
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17
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Conover HN, Argueso JL. Contrasting mechanisms of de novo copy number mutagenesis suggest the existence of different classes of environmental copy number mutagens. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2016; 57:3-9. [PMID: 26247157 DOI: 10.1002/em.21967] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 07/05/2015] [Accepted: 07/07/2015] [Indexed: 05/23/2023]
Abstract
While gene copy number variations (CNVs) are abundant in the human genome, and often are associated with disease consequences, the mutagenic pathways and environmental exposures that cause these large structural mutations are understudied relative to conventional nucleotide substitutions in DNA. The members of the environmental mutagenesis community are currently seeking to remedy this deficiency, and there is a renewed interest in the development of mutagenicity assays to identify and characterize compounds that may induce de novo CNVs in humans. To achieve this goal, it is critically important to acknowledge that CNVs exist in two very distinct classes: nonrecurrent and recurrent CNVs. The goal of this commentary is to emphasize the deep contrasts that exist between the proposed pathways that lead to these two mutation classes. Nonrecurrent de novo CNVs originate primarily in mitotic cells through replication-dependent DNA repair pathways that involve microhomologies (<10 bp), and are detected at higher frequency in children of older fathers. In contrast, recurrent de novo CNVs are most often formed in meiotic cells through homologous recombination between nonallelic large low-copy repeats (>10,000 bp), without an associated paternal age effect. Given the biological differences between the two CNV classes, it is our belief that nonrecurrent and recurrent CN mutagens will probably differ substantially in their modes of action. Therefore, each CNV class may require their own uniquely designed assays, so that we as a field may succeed in uncovering the broadest possible spectrum of environmental CN mutagens.
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Affiliation(s)
- Hailey N Conover
- Department of Environmental and Radiological Health Sciences, Cell and Molecular Biology Graduate Program, Institute for Genome Architecture and Function, Colorado State University, Fort Collins, Colorado
| | - Juan Lucas Argueso
- Department of Environmental and Radiological Health Sciences, Cell and Molecular Biology Graduate Program, Institute for Genome Architecture and Function, Colorado State University, Fort Collins, Colorado
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18
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Li HH, Hyduke DR, Chen R, Heard P, Yauk CL, Aubrecht J, Fornace AJ. Development of a toxicogenomics signature for genotoxicity using a dose-optimization and informatics strategy in human cells. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2015; 56:505-19. [PMID: 25733355 PMCID: PMC4506269 DOI: 10.1002/em.21941] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 01/19/2015] [Indexed: 05/11/2023]
Abstract
The development of in vitro molecular biomarkers to accurately predict toxicological effects has become a priority to advance testing strategies for human health risk assessment. The application of in vitro transcriptomic biomarkers promises increased throughput as well as a reduction in animal use. However, the existing protocols for predictive transcriptional signatures do not establish appropriate guidelines for dose selection or account for the fact that toxic agents may have pleiotropic effects. Therefore, comparison of transcriptome profiles across agents and studies has been difficult. Here we present a dataset of transcriptional profiles for TK6 cells exposed to a battery of well-characterized genotoxic and nongenotoxic chemicals. The experimental conditions applied a new dose optimization protocol that was based on evaluating expression changes in several well-characterized stress-response genes using quantitative real-time PCR in preliminary dose-finding studies. The subsequent microarray-based transcriptomic analyses at the optimized dose revealed responses to the test chemicals that were typically complex, often exhibiting substantial overlap in the transcriptional responses between a variety of the agents making analysis challenging. Using the nearest shrunken centroids method we identified a panel of 65 genes that could accurately classify toxicants as genotoxic or nongenotoxic. To validate the 65-gene panel as a genomic biomarker of genotoxicity, the gene expression profiles of an additional three well-characterized model agents were analyzed and a case study demonstrating the practical application of this genomic biomarker-based approach in risk assessment was performed to demonstrate its utility in genotoxicity risk assessment.
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Affiliation(s)
- Heng-Hong Li
- Department of Biochemistry and Molecular & Cellular Biology, and Department of Oncology, Georgetown University Medical Center, Washington, DC 20057
| | - Daniel R. Hyduke
- Department of Biochemistry and Molecular & Cellular Biology, and Department of Oncology, Georgetown University Medical Center, Washington, DC 20057
- Biological Engineering Department, Utah State University, Logan, UT 84321
| | - Renxiang Chen
- Department of Biochemistry and Molecular & Cellular Biology, and Department of Oncology, Georgetown University Medical Center, Washington, DC 20057
| | - Pamela Heard
- Pfizer Global Research and Development, Drug Safety Research and Development, Eastern Point Road, Groton, CT 06340
| | - Carole L. Yauk
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, K1A 0K9, Canada
| | - Jiri Aubrecht
- Pfizer Global Research and Development, Drug Safety Research and Development, Eastern Point Road, Groton, CT 06340
| | - Albert J. Fornace
- Department of Biochemistry and Molecular & Cellular Biology, and Department of Oncology, Georgetown University Medical Center, Washington, DC 20057
- To whom correspondence should be addressed at: Lombardi Comprehensive Cancer Center, 3970 Reservoir Rd. NW, Room E504, Washington, DC 20057. Fax: (202) 687-3140.,
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19
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Dertinger SD, Avlasevich SL, Bemis JC, Chen Y, MacGregor JT. Human erythrocyte PIG-A assay: an easily monitored index of gene mutation requiring low volume blood samples. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2015; 56:366-77. [PMID: 25412990 PMCID: PMC4406781 DOI: 10.1002/em.21924] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 10/29/2014] [Indexed: 05/21/2023]
Abstract
This laboratory has previously described a method for scoring the incidence of rodent blood Pig-a mutant phenotype erythrocytes using immunomagnetic separation in conjunction with flow cytometric analysis (In Vivo MutaFlow®). The current work extends this approach to human blood. The frequencies of CD59- and CD55-negative reticulocytes (RET(CD59-/CD55-)) and erythrocytes (RBC(CD59-/CD55-)) serve as phenotypic reporters of PIG-A gene mutation. Immunomagnetic separation was found to provide an effective means of increasing the number of reticulocytes and erythrocytes evaluated. Technical replicates were utilized to provide a sufficient number of cells for precise scoring while at the same time controlling for procedural accuracy by allowing comparison of replicate values. Cold whole blood samples could be held for at least one week without affecting reticulocyte, RET(CD59-/CD55-) or RBC(CD59-/CD55-) frequencies. Specimens from a total of 52 nonsmoking, self-reported healthy adult subjects were evaluated. The mean frequency of RET(CD59-/CD55-) and RBC(CD59-/CD55-) were 6.0 × 10(-6) and 2.9 × 10(-6), respectively. The difference is consistent with a modest selective pressure against mutant phenotype erythrocytes in the circulation, and suggests advantages of studying both populations of erythrocytes. Whereas intra-subject variability was low, inter-subject variability was relatively high, with RET(CD59-/CD55-) frequencies differing by more than 30-fold. There was an apparent correlation between age and mutant cell frequencies. Taken together, the results indicate that the frequency of human PIG-A mutant phenotype cells can be efficiently and reliably estimated using a labeling and analysis protocol that is well established for rodent-based studies. The applicability of the assay across species, its simplicity and statistical power, and the relatively non-invasive nature of the assay should benefit myriad research areas involving DNA damage, including studies of environmental factors that modify "spontaneous" mutation frequencies.
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Affiliation(s)
- Stephen D. Dertinger
- Litron Laboratories, Rochester, New York
- Correspondence to: Stephen D. Dertinger, Litron Laboratories, 3500 Winton Place, Rochester, NY 14623.
| | | | | | - Yuhchyau Chen
- Department of Radiation Oncology, University of Rochester Medical Center, Rochester, New York
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20
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Labash C, Avlasevich SL, Carlson K, Torous DK, Berg A, Bemis JC, MacGregor JT, Dertinger SD. Comparison of male versus female responses in the Pig-a mutation assay. Mutagenesis 2015; 30:349-57. [PMID: 25833915 DOI: 10.1093/mutage/geu055] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Validation of the Pig-a gene mutation assay has been based mainly on studies in male rodents. To determine if the mutagen-induced responses of the X-linked Pig-a gene differ in females compared to males, 7- or 14-week old male and female Sprague Dawley rats were exposed to N-ethyl-N-nitrosourea (ENU). In the study with the 7-week old rats, exposure was to 0, 1, 5 or 25mg ENU/kg/day for three consecutive days (study Days 1-3). Pig-a mutant phenotype reticulocyte (RET(CD59-)) and mutant phenotype erythrocyte (RBC(CD59-)) frequencies were determined on study Days -4, 15, 29 and 46 using immunomagnetic separation in conjunction with flow cytometric analysis (In Vivo MutaFlow®). Additionally, blood samples collected on Day 4 were analysed for micronucleated reticulocyte (MN-RET) frequency (In Vivo MicroFlow®). The percentage of reticulocytes (%RET) was markedly higher in the 7-week old males compared to females through Day 15 (2.39-fold higher on Day -4). At 25mg/kg/day, ENU reduced Day 4 RET frequencies in both sexes, and the two highest dose levels resulted in elevated MN-RET frequencies, with no sex or treatment × sex interaction. The two highest dose levels significantly elevated the frequencies of mean RET(CD59-) and RBC(CD59-) in both sexes from Day 15 onward. RET(CD59-) and RBC(CD59-) frequencies were somewhat lower for females compared to males at the highest dose level studied, and differences in RET(CD59-) resulted in a statistically significant interaction effect of treatment × sex. In the study with 14-week old rats, treatment was for 3 days with 0 or 25mg ENU/kg/day. RET frequencies differed to a lesser degree between the sexes, and in this case there was no evidence of a treatment × sex interaction. These results suggest that the slightly higher response in younger males than in the younger females may be related to differences in erythropoiesis function at that age. In conclusion, while some quantitative differences were noted, there were no qualitative differences in how males and females responded to a prototypical mutagen, and support the contention that both sexes are equally acceptable for Pig-a gene mutation studies.
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21
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Zeiger E, Gollapudi B, Aardema MJ, Auerbach S, Boverhof D, Custer L, Dedon P, Honma M, Ishida S, Kasinski AL, Kim JH, Manjanatha MG, Marlowe J, Pfuhler S, Pogribny I, Slikker W, Stankowski LF, Tanir JY, Tice R, van Benthem J, White P, Witt KL, Thybaud V. Opportunities to integrate new approaches in genetic toxicology: an ILSI-HESI workshop report. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2015; 56:277-85. [PMID: 25482136 PMCID: PMC4615680 DOI: 10.1002/em.21923] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 10/28/2014] [Indexed: 05/20/2023]
Abstract
Genetic toxicity tests currently used to identify and characterize potential human mutagens and carcinogens rely on measurements of primary DNA damage, gene mutation, and chromosome damage in vitro and in rodents. The International Life Sciences Institute Health and Environmental Sciences Institute (ILSI-HESI) Committee on the Relevance and Follow-up of Positive Results in In Vitro Genetic Toxicity Testing held an April 2012 Workshop in Washington, DC, to consider the impact of new understanding of biology and new technologies on the identification and characterization of genotoxic substances, and to identify new approaches to inform more accurate human risk assessment for genetic and carcinogenic effects. Workshop organizers and speakers were from industry, academe, and government. The Workshop focused on biological effects and technologies that would potentially yield the most useful information for evaluating human risk of genetic damage. Also addressed was the impact that improved understanding of biology and availability of new techniques might have on genetic toxicology practices. Workshop topics included (1) alternative experimental models to improve genetic toxicity testing, (2) Biomarkers of epigenetic changes and their applicability to genetic toxicology, and (3) new technologies and approaches. The ability of these new tests and technologies to be developed into tests to identify and characterize genotoxic agents; to serve as a bridge between in vitro and in vivo rodent, or preferably human, data; or to be used to provide dose response information for quantitative risk assessment was also addressed. A summary of the workshop and links to the scientific presentations are provided.
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Affiliation(s)
- Errol Zeiger
- Errol Zeiger Consulting, Chapel Hill, North Carolina
- Correspondence to: Errol Zeiger.
| | | | - Marilyn J. Aardema
- Marilyn Aardema Consulting LLC, BioReliance Corporation, Rockville, Maryland
| | - Scott Auerbach
- National Institute of Environmental Health Sciences, Division of the National Toxicology Program, Research Triangle Park, North Carolina
| | | | - Laura Custer
- Department of Genetic Toxicology, Bristol-Myers Squibb Co., East Syracuse, New York
| | - Peter Dedon
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Masamitsu Honma
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, Tokyo, Japan
| | - Seiichi Ishida
- Division of Pharmacology, National Institute of Health Sciences, Tokyo, Japan
| | - Andrea L. Kasinski
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut
| | - James H. Kim
- ILSI Health and Environmental Sciences Institute, Washington, District of Columbia
| | - Mugimane G. Manjanatha
- National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas
| | | | | | - Igor Pogribny
- National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas
| | - William Slikker
- National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas
| | | | - Jennifer Y. Tanir
- ILSI Health and Environmental Sciences Institute, Washington, District of Columbia
| | - Raymond Tice
- National Institute of Environmental Health Sciences, Division of the National Toxicology Program, Research Triangle Park, North Carolina
| | - Jan van Benthem
- National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - Paul White
- Environmental Health Sciences and Research Division, Health Canada, Ottawa, Canada
| | - Kristine L. Witt
- National Institute of Environmental Health Sciences, Division of the National Toxicology Program, Research Triangle Park, North Carolina
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22
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Wasalathanthri DP, Li D, Song D, Zheng Z, Choudhary D, Jansson I, Lu X, Schenkman JB, Rusling JF. Elucidating Organ-Specific Metabolic Toxicity Chemistry from Electrochemiluminescent Enzyme/DNA Arrays and Bioreactor Bead-LC-MS/MS. Chem Sci 2015; 6:2457-2468. [PMID: 25798217 PMCID: PMC4364445 DOI: 10.1039/c4sc03401e] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 02/12/2015] [Indexed: 12/15/2022] Open
Abstract
Human toxic responses are very often related to metabolism. Liver metabolism is traditionally studied, but other organs also convert chemicals and drugs to reactive metabolites leading to toxicity. When DNA damage is found, the effects are termed genotoxic. Here we describe a comprehensive new approach to evaluate chemical genotoxicity pathways from metabolites formed in-situ by a broad spectrum of liver, lung, kidney and intestinal enzymes. DNA damage rates are measured with a microfluidic array featuring a 64-nanowell chip to facilitate fabrication of films of DNA, electrochemiluminescent (ECL) detection polymer [Ru(bpy)2(PVP)10]2+ {(PVP = poly(4-vinylpyridine)} and metabolic enzymes. First, multiple enzyme reactions are run on test compounds using the array, then ECL light related to the resulting DNA damage is measured. A companion method next facilitates reaction of target compounds with DNA/enzyme-coated magnetic beads in 96 well plates, after which DNA is hydrolyzed and nucleobase-metabolite adducts are detected by LC-MS/MS. The same organ enzymes are used as in the arrays. Outcomes revealed nucleobase adducts from DNA damage, enzymes responsible for reactive metabolites (e.g. cyt P450s), influence of bioconjugation, relative dynamics of enzymes suites from different organs, and pathways of possible genotoxic chemistry. Correlations between DNA damage rates from the cell-free array and organ-specific cell-based DNA damage were found. Results illustrate the power of the combined DNA/enzyme microarray/LC-MS/MS approach to efficiently explore a broad spectrum of organ-specific metabolic genotoxic pathways for drugs and environmental chemicals.
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Affiliation(s)
| | - Dandan Li
- Department of Chemistry , University of Connecticut , Storrs , Connecticut 06269 , USA .
| | - Donghui Song
- Department of Pharmaceutical Sciences , University of Connecticut , Storrs , Connecticut 06269 , USA
| | - Zhifang Zheng
- Department of Chemistry , University of Connecticut , Storrs , Connecticut 06269 , USA .
| | - Dharamainder Choudhary
- Department of Surgery , University of Connecticut Health Center , Farmington , Connecticut 06032 , USA
| | - Ingela Jansson
- Department of Cell Biology , University of Connecticut Health Center , Farmington , Connecticut 06032 , USA
| | - Xiuling Lu
- Department of Pharmaceutical Sciences , University of Connecticut , Storrs , Connecticut 06269 , USA
| | - John B. Schenkman
- Department of Cell Biology , University of Connecticut Health Center , Farmington , Connecticut 06032 , USA
| | - James F. Rusling
- Department of Chemistry , University of Connecticut , Storrs , Connecticut 06269 , USA .
- National University of Ireland at Galway , Ireland
- Department of Cell Biology , University of Connecticut Health Center , Farmington , Connecticut 06032 , USA
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23
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Abstract
Computational approaches offer the attraction of being both fast and cheap to run being able to process thousands of chemical structures in a few minutes. As with all new technology, there is a tendency for these approaches to be hyped up and claims of reliability and performance may be exaggerated. So just how good are these computational methods?
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Affiliation(s)
- Nigel Greene
- Worldwide Medicinal Chemistry
- Pfizer Inc. Groton
- CT 06340, USA
| | - William Pennie
- Drug Safety Research and Evaluation
- Takeda Pharmaceuticals International Inc
- Cambridge, USA
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24
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Johnson GE, Slob W, Doak SH, Fellows MD, Gollapudi BB, Heflich RH, Rees BJ, Soeteman-Hernández LG, Verma JR, Wills JW, Jenkins GJS, White PA. New approaches to advance the use of genetic toxicology analyses for human health risk assessment. Toxicol Res (Camb) 2015. [DOI: 10.1039/c4tx00118d] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Genetic toxicology testing has a crucial role in the safety assessment of substances of societal value by reducing human exposure to potential somatic and germ cell mutagens.
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Affiliation(s)
- George E. Johnson
- Institute of Life Science
- College of Medicine
- Swansea University
- Swansea
- UK
| | - Wout Slob
- Institute of Life Science
- College of Medicine
- Swansea University
- Swansea
- UK
| | - Shareen H. Doak
- Institute of Life Science
- College of Medicine
- Swansea University
- Swansea
- UK
| | | | | | - Robert H. Heflich
- National Centre for Toxicological Research
- U.S. Food and Drug Administration
- Jefferson
- USA
| | - Ben J. Rees
- Institute of Life Science
- College of Medicine
- Swansea University
- Swansea
- UK
| | - Lya G. Soeteman-Hernández
- Center for Health Protection
- National Institute for Public Health and the Environment (RIVM)
- Bilthoven
- Netherlands
| | - Jatin R. Verma
- Institute of Life Science
- College of Medicine
- Swansea University
- Swansea
- UK
| | - John W. Wills
- Institute of Life Science
- College of Medicine
- Swansea University
- Swansea
- UK
| | | | - Paul A. White
- Environmental Health Sciences and Research Bureau
- Healthy Environments and Consumer Safety Branch
- Health Canada
- Ottawa
- Canada
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Rusling JF, Wasalathanthri DP, Schenkman JB. Thin multicomponent films for functional enzyme devices and bioreactor particles. SOFT MATTER 2014; 10:8145-8156. [PMID: 25209428 PMCID: PMC4183705 DOI: 10.1039/c4sm01679c] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Complex functional films containing enzymes and other biomolecules are easily fabricated in nm-scale thicknesses by using layer-by-layer (LbL) methodologies first popularized by Lvov and Decher. In this review, we highlight the high level functional capabilities possible with LbL films of biomolecules based on our own research experiences. We first describe the basics of enzyme film fabrication by LbL alternate electrostatic adsorption, then discuss how to make functional enzyme-polyion films of remarkably high stability. Focusing on cytochrome P450s, we discuss films developed to electrochemically activate the natural catalytic cycle of these key metabolic enzymes. We then describe multifunctional, multicomponent DNA/enzyme/polyion films on arrays and particle surfaces for high throughput metabolic toxicity screening using electrochemiluminescence and LC-MS/MS. Using multicomponent LbL films, complex functionality for bioanalytical and biochemical purposes can be achieved that is difficult or impossible using conventional approaches.
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Affiliation(s)
- James F Rusling
- Department of Chemistry, University of Connecticut, Storrs, CT 06269, USA.
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26
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Hansen MK, Sharma AK, Dybdahl M, Boberg J, Kulahci M. In vivo Comet assay – statistical analysis and power calculations of mice testicular cells. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2014; 774:29-40. [DOI: 10.1016/j.mrgentox.2014.08.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 08/16/2014] [Accepted: 08/29/2014] [Indexed: 10/24/2022]
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Garcia-Canton C, Errington G, Anadon A, Meredith C. Characterisation of an aerosol exposure system to evaluate the genotoxicity of whole mainstream cigarette smoke using the in vitro γH2AX assay by high content screening. BMC Pharmacol Toxicol 2014; 15:41. [PMID: 25056295 PMCID: PMC4122049 DOI: 10.1186/2050-6511-15-41] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 07/16/2014] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The genotoxic effect of cigarette smoke is routinely measured by treating cells with cigarette Particulate Matter (PM) at different dose levels in submerged cell cultures. However, PM exposure cannot be considered as a complete exposure as it does not contain the gas phase component of the cigarette smoke. The in vitro γH2AX assay by High Content Screening (HCS) has been suggested as a complementary tool to the standard battery of genotoxicity assays as it detects DNA double strand breaks in a high-throughput fashion. The aim of this study was to further optimise the in vitro γH2AX assay by HCS to enable aerosol exposure of human bronchial epithelial BEAS-2B cells at the air-liquid interface (ALI). METHODS Whole mainstream cigarette smoke (WMCS) from two reference cigarettes (3R4F and M4A) were assessed for their genotoxic potential. During the study, a further characterisation of the Borgwaldt RM20S® aerosol exposure system to include single dilution assessment with a reference gas was also carried out. RESULTS The results of the optimisation showed that both reference cigarettes produced a positive genotoxic response at all dilutions tested. However, the correlation between dose and response was low for both 3R4F and M4A (Pearson coefficient, r = -0.53 and -0.44 respectively). During the additional characterisation of the exposure system, it was observed that several pre-programmed dilutions did not perform as expected. CONCLUSIONS Overall, the in vitro γH2AX assay by HCS could be used to evaluate WMCS in cell cultures at the ALI. Additionally, the extended characterisation of the exposure system indicates that assessing the performance of the dilutions could improve the existing routine QC checks.
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Affiliation(s)
- Carolina Garcia-Canton
- British American Tobacco, Group Research and Development, Regents Park Road, Southampton, Hampshire SO15 8TL, UK
- Department of Toxicology and Pharmacology, Universidad Complutense de Madrid, Madrid, Spain
| | - Graham Errington
- British American Tobacco, Group Research and Development, Regents Park Road, Southampton, Hampshire SO15 8TL, UK
| | - Arturo Anadon
- Department of Toxicology and Pharmacology, Universidad Complutense de Madrid, Madrid, Spain
| | - Clive Meredith
- British American Tobacco, Group Research and Development, Regents Park Road, Southampton, Hampshire SO15 8TL, UK
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de Carvalho AS, Salomão K, de Castro SL, Conde TR, Zamith HPDS, Caffarena ER, Hall BS, Wilkinson SR, Boechat N. Megazol and its bioisostere 4H-1,2,4-triazole: comparing the trypanocidal, cytotoxic and genotoxic activities and their in vitro and in silico interactions with the Trypanosoma brucei nitroreductase enzyme. Mem Inst Oswaldo Cruz 2014; 109:315-23. [PMID: 24676659 PMCID: PMC4131783 DOI: 10.1590/0074-0276140497] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 02/13/2014] [Indexed: 11/22/2022] Open
Abstract
Megazol (7) is a 5-nitroimidazole that is highly active against Trypanosoma cruzi and Trypanosoma brucei, as well as drug-resistant forms of trypanosomiasis. Compound 7 is not used clinically due to its mutagenic and genotoxic properties, but has been largely used as a lead compound. Here, we compared the activity of 7 with its 4H-1,2,4-triazole bioisostere (8) in bloodstream forms of T. brucei and T. cruzi and evaluated their activation by T. brucei type I nitroreductase (TbNTR) enzyme. We also analysed the cytotoxic and genotoxic effects of these compounds in whole human blood using Comet and fluorescein diacetate/ethidium bromide assays. Although the only difference between 7 and 8 is the substitution of sulphur (in the thiadiazole in 7) for nitrogen (in the triazole in 8), the results indicated that 8 had poorer antiparasitic activity than 7 and was not genotoxic, whereas 7 presented this effect. The determination of Vmax indicated that although 8 was metabolised more rapidly than 7, it bounds to the TbNTR with better affinity, resulting in equivalent kcat/KM values. Docking assays of 7 and 8 performed within the active site of a homology model of the TbNTR indicating that 8 had greater affinity than 7.
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Affiliation(s)
| | - Kelly Salomão
- Laboratório de Biologia Celular, Instituto Oswaldo Cruz-Fiocruz, Rio de
Janeiro, RJ, Brasil
| | | | - Taline Ramos Conde
- Departamento de Farmacologia e Toxicologia, Instituto Nacional de
Controle de Qualidade em Saúde - Fiocruz, Rio de Janeiro, RJ,
Brasil
| | - Helena Pereira da Silva Zamith
- Departamento de Farmacologia e Toxicologia, Instituto Nacional de
Controle de Qualidade em Saúde - Fiocruz, Rio de Janeiro, RJ,
Brasil
| | | | - Belinda Suzette Hall
- School of Biological and Chemical Sciences, Queen Mary University of
London, London, UK
| | | | - Núbia Boechat
- Departamento de Síntese de Fármacos, Farmanguinhos - Fiocruz, Rio de
Janeiro, RJ, Brasil
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29
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Oomen AG, Bos PMJ, Fernandes TF, Hund-Rinke K, Boraschi D, Byrne HJ, Aschberger K, Gottardo S, von der Kammer F, Kühnel D, Hristozov D, Marcomini A, Migliore L, Scott-Fordsmand J, Wick P, Landsiedel R. Concern-driven integrated approaches to nanomaterial testing and assessment--report of the NanoSafety Cluster Working Group 10. Nanotoxicology 2014; 8:334-48. [PMID: 23641967 PMCID: PMC4002633 DOI: 10.3109/17435390.2013.802387] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 05/01/2013] [Indexed: 12/21/2022]
Abstract
Bringing together topic-related European Union (EU)-funded projects, the so-called "NanoSafety Cluster" aims at identifying key areas for further research on risk assessment procedures for nanomaterials (NM). The outcome of NanoSafety Cluster Working Group 10, this commentary presents a vision for concern-driven integrated approaches for the (eco-)toxicological testing and assessment (IATA) of NM. Such approaches should start out by determining concerns, i.e., specific information needs for a given NM based on realistic exposure scenarios. Recognised concerns can be addressed in a set of tiers using standardised protocols for NM preparation and testing. Tier 1 includes determining physico-chemical properties, non-testing (e.g., structure-activity relationships) and evaluating existing data. In tier 2, a limited set of in vitro and in vivo tests are performed that can either indicate that the risk of the specific concern is sufficiently known or indicate the need for further testing, including details for such testing. Ecotoxicological testing begins with representative test organisms followed by complex test systems. After each tier, it is evaluated whether the information gained permits assessing the safety of the NM so that further testing can be waived. By effectively exploiting all available information, IATA allow accelerating the risk assessment process and reducing testing costs and animal use (in line with the 3Rs principle implemented in EU Directive 2010/63/EU). Combining material properties, exposure, biokinetics and hazard data, information gained with IATA can be used to recognise groups of NM based upon similar modes of action. Grouping of substances in return should form integral part of the IATA themselves.
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Affiliation(s)
- Agnes G. Oomen
- IVM, National Institute for Public Health and the Environment, Bilthoven, The Netherlands
| | - Peter M. J. Bos
- IVM, National Institute for Public Health and the Environment, Bilthoven, The Netherlands
| | | | - Kerstin Hund-Rinke
- Fraunhofer Institute for Molecular Biology and Applied Ecology, Schmallenberg, Germany
| | | | - Hugh J. Byrne
- Focas Research Institute, Dublin Institute of Technology, Dublin, Ireland
| | - Karin Aschberger
- Joint Research Centre – Institute for Health and Consumer Protection, Ispra, Italy
| | - Stefania Gottardo
- Joint Research Centre – Institute for Health and Consumer Protection, Ispra, Italy
| | | | - Dana Kühnel
- Bioanalytical Ecotoxicology, UFZ – Helmholtz Centre for Environmental Research, Leipzig, Germany
| | | | | | - Lucia Migliore
- Department of Translational Research & New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | | | - Peter Wick
- Empa, Swiss Federal Laboratories for Materials Science and Technology, St. Gallen, Switzerland
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Ireno IC, Baumann C, Stöber R, Hengstler JG, Wiesmüller L. Fluorescence-based recombination assay for sensitive and specific detection of genotoxic carcinogens in human cells. Arch Toxicol 2014; 88:1141-59. [PMID: 24671466 DOI: 10.1007/s00204-014-1229-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 03/18/2014] [Indexed: 10/25/2022]
Abstract
In vitro genotoxicity tests are known to suffer from several shortcomings, mammalian cell-based assays, in particular, from low specificities. Following a novel concept of genotoxicity detection, we developed a fluorescence-based method in living human cells. The assay quantifies DNA recombination events triggered by DNA double-strand breaks and damage-induced replication fork stalling predicted to detect a broad spectrum of genotoxic modes of action. To maximize sensitivities, we engineered a DNA substrate encompassing a chemoresponsive element from the human genome. Using this substrate, we screened various human tumor and non-transformed cell types differing in the DNA damage response, which revealed that detection of genotoxic carcinogens was independent of the p53 status but abrogated by apoptosis. Cell types enabling robust and sensitive genotoxicity detection were selected for the generation of reporter clones with chromosomally integrated DNA recombination substrate. Reporter cell lines were scrutinized with 21 compounds, stratified into five sets according to the established categories for identification of carcinogenic compounds: genotoxic carcinogens ("true positives"), non-genotoxic carcinogens, compounds without genotoxic or carcinogenic effect ("true negatives") and non-carcinogenic compounds, which have been reported to induce chromosomal aberrations or mutations in mammalian cell-based assays ("false positives"). Our results document detection of genotoxic carcinogens in independent cell clones and at levels of cellular toxicities <60 % with a sensitivity of >85 %, specificity of ≥90 % and detection of false-positive compounds <17 %. Importantly, through testing cyclophosphamide in combination with primary hepatocyte cultures, we additionally provide proof-of-concept for the identification of carcinogens requiring metabolic activation using this novel assay system.
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Affiliation(s)
- Ivanildce C Ireno
- Department of Obstetrics and Gynecology, University of Ulm, Prittwitzstrasse 43, 89075, Ulm, Germany
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31
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de Andrade Júnior MC, Andrade JS. Amazonian Fruits: An Overview of Nutrients, Calories and Use in Metabolic Disorders. ACTA ACUST UNITED AC 2014. [DOI: 10.4236/fns.2014.517182] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Wasalathanthri DP, Malla S, Bist I, Tang CK, Faria RC, Rusling JF. High-throughput metabolic genotoxicity screening with a fluidic microwell chip and electrochemiluminescence. LAB ON A CHIP 2013; 13:4554-62. [PMID: 24113555 PMCID: PMC3901045 DOI: 10.1039/c3lc50698c] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A high throughput electrochemiluminescent (ECL) chip was fabricated and integrated into a fluidic system for screening toxicity-related chemistry of drug and pollutant metabolites. The chip base is conductive pyrolytic graphite onto which are printed 64 microwells capable of holding one-μL droplets. Films combining DNA, metabolic enzymes and an ECL-generating ruthenium metallopolymer (Ru(II)PVP) are fabricated in these microwells. The system runs metabolic enzyme reactions, and subsequently detects DNA damage caused by reactive metabolites. The performance of the chip was tested by measuring DNA damage caused by metabolites of the well-known procarcinogen benzo[a]pyrene (B[a]P). Liver microsomes and cytochrome P450 (cyt P450) enzymes were used with and without epoxide hydrolase (EH), a conjugative enzyme required for multi-enzyme bioactivation of B[a]P. DNA adduct formation was confirmed by determining specific DNA-metabolite adducts using similar films of DNA/enzyme on magnetic bead biocolloid reactors, hydrolyzing the DNA, and analyzing by capillary liquid chromatography-mass spectrometry (CapLC-MS/MS). The fluidic chip was also used to measure IC50-values of inhibitors of cyt P450s. All results show good correlation with reported enzyme activity and inhibition assays.
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Garcia-Canton C, Anadon A, Meredith C. Genotoxicity evaluation of individual cigarette smoke toxicants using the in vitro γH2AX assay by high content screening. Toxicol Lett 2013; 223:81-7. [PMID: 24021168 DOI: 10.1016/j.toxlet.2013.08.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 08/29/2013] [Accepted: 08/31/2013] [Indexed: 01/01/2023]
Abstract
Cigarette smoke is a complex mixture consisting of more than 5600 identified chemical constituents of which approximately 150 have been identified so far as "tobacco smoke toxicants". Proposals made by the World Health Organisation Framework Convention on Tobacco Control mandate the lowering of nine tobacco smoke priority toxicants, including 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), N-nitrosonornicotine (NNN), and benzo[a]pyrene (B[a]P) and monitoring the levels of a further nine including cadmium. Here, we evaluated the genotoxic potential in human bronchial epithelial BEAS-2B cells of four cigarette smoke toxicants; NNK, NNN, B[a]P and cadmium using the novel in vitro γH2AX assay by High Content Screening (HCS). We also examined the genotoxicity of binary mixtures of NNK and NNN reporting their relative contribution to the genotoxic end-point. The results of this preliminary assessment showed that the in vitro γH2AX assay by HCS could be used as a pre-screening tool to detect and quantify the genotoxicity effect of cigarette smoke toxicants individually and in binary mixture. Moreover, the data produced could contribute to the prioritisation of toxicant reduction research in modified tobacco products.
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Affiliation(s)
- Carolina Garcia-Canton
- British American Tobacco, Group Research and Development, Regents Park Road, Southampton, Hampshire SO15 8TL, United Kingdom; Department of Toxicology and Pharmacology, Universidad Complutense de Madrid, Madrid, Spain.
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Garcia-Canton C, Anadon A, Meredith C. Assessment of the in vitro γH2AX assay by High Content Screening as a novel genotoxicity test. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2013; 757:158-66. [PMID: 23988589 DOI: 10.1016/j.mrgentox.2013.08.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 07/07/2013] [Accepted: 08/07/2013] [Indexed: 10/26/2022]
Abstract
The γH2AX assay is widely used as a marker of DNA damage in multiple scientific fields such as cancer biomarker, clinical studies and radiation biology. In particular, the in vitro γH2AX assay has been suggested as a novel in vitro genotoxicity test with potential as a pre-screening tool. However, to date, limited assessments have been carried out to evaluate the sensitivity, specificity and accuracy of the in vitro γH2AX assay. In this study, the microscopy-based system combining automated cellular image acquisition with software quantification for High Content Screening (HCS) has been used for the first time to evaluate the in vitro γH2AX assay. A panel of well-characterised genotoxic and non-genotoxic compounds was selected to assess the performance of the in vitro γH2AX assay in the human bronchial epithelial cell line BEAS-2B. The results obtained during this preliminary assessment indicate that the in vitro γH2AX assay has a high accuracy (86%) as a result of high sensitivity and specificity (86-92% and 80-88% respectively). Our data highlight the potential for γH2AX detection in HCS as a complement to the current regulatory genotoxicity battery of in vitro assays. We therefore recommend more comprehensive assessments to confirm the performance of the in vitro γH2AX assay by HCS with a more extensive set of compounds.
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Affiliation(s)
- Carolina Garcia-Canton
- British American Tobacco, Group Research and Development, Regents Park Road, Southampton, Hampshire SO15 8TL, United Kingdom; Department of Toxicology and Pharmacology, Universidad Complutense de Madrid, Madrid, Spain.
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35
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Mani V, Kadimisetty K, Malla S, Joshi AA, Rusling JF. Paper-based electrochemiluminescent screening for genotoxic activity in the environment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:1937-44. [PMID: 23331021 PMCID: PMC3578158 DOI: 10.1021/es304426j] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
A low cost, microfluidic paper electrochemical device (μPED) was fabricated using screen printing of electrodes and heat transfer of patterned wax paper onto filter paper. The μPED features films of a light-emitting ruthenium metallopolymer, microsomal metabolic enzymes, and DNA to detect potential genotoxic pollutant activity in environmental samples. Unlike conventional analytical methods that detect specific pollutant compounds, the μPED was designed to rapidly measure the presence of genotoxic equivalents in environmental samples with the signal related to benzo[a]pyrene (B[a]P) as a reference standard. The analytical end point is the detection of DNA damage from metabolites produced in the device using an electrochemiluminescence output measured with a charge-coupled device (CCD) camera. Proof-of-concept of this measurement was established for smoke, water, and food samples. The μPED provides a rapid screening tool for on-site environmental monitoring that specifically monitors the genotoxic reactivity of metabolites of toxic compounds present in the samples.
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Affiliation(s)
- Vigneshwaran Mani
- Department of Chemistry, University of Connecticut, Storrs, CT, USA 06269
| | | | - Spundana Malla
- Department of Chemistry, University of Connecticut, Storrs, CT, USA 06269
| | - Amit A. Joshi
- Department of Chemistry, University of Connecticut, Storrs, CT, USA 06269
| | - James F. Rusling
- Department of Chemistry, University of Connecticut, Storrs, CT, USA 06269
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, USA 06032
- School of Chemistry, National University of Ireland, Galway
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36
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Wei T, Zhang C, Xu X, Hanna M, Zhang X, Wang Y, Dai H, Xiao W. Construction and evaluation of two biosensors based on yeast transcriptional response to genotoxic chemicals. Biosens Bioelectron 2013; 44:138-45. [PMID: 23416315 DOI: 10.1016/j.bios.2013.01.029] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 01/13/2013] [Accepted: 01/15/2013] [Indexed: 11/16/2022]
Abstract
It has been well established that essentially all microbial mutagens are rodent carcinogens, yet current mutagen detection systems are limited by their detection sensitivity. Here we report the construction of a pair of hypersensitive biosensors by optimizing both reporters and the host strain. The resulting RNR3-yEGFP and HUG1-yEGFP reporters and the septuple yeast mutant in combination with the automated protocol not only remarkably enhance the detection sensitivity, but also allow a high throughput screen of environmental genotoxins. This system is deemed much more sensitive than similar yeast and bacterium-based tests for all selected chemicals examined in this study.
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Affiliation(s)
- Ting Wei
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, PR China
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37
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Gollapudi BB, Johnson GE, Hernandez LG, Pottenger LH, Dearfield KL, Jeffrey AM, Julien E, Kim JH, Lovell DP, Macgregor JT, Moore MM, van Benthem J, White PA, Zeiger E, Thybaud V. Quantitative approaches for assessing dose-response relationships in genetic toxicology studies. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2013; 54:8-18. [PMID: 22987251 DOI: 10.1002/em.21727] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 07/19/2012] [Accepted: 07/23/2012] [Indexed: 06/01/2023]
Abstract
Genetic toxicology studies are required for the safety assessment of chemicals. Data from these studies have historically been interpreted in a qualitative, dichotomous "yes" or "no" manner without analysis of dose-response relationships. This article is based upon the work of an international multi-sector group that examined how quantitative dose-response relationships for in vitro and in vivo genetic toxicology data might be used to improve human risk assessment. The group examined three quantitative approaches for analyzing dose-response curves and deriving point-of-departure (POD) metrics (i.e., the no-observed-genotoxic-effect-level (NOGEL), the threshold effect level (Td), and the benchmark dose (BMD)), using data for the induction of micronuclei and gene mutations by methyl methanesulfonate or ethyl methanesulfonate in vitro and in vivo. These results suggest that the POD descriptors obtained using the different approaches are within the same order of magnitude, with more variability observed for the in vivo assays. The different approaches were found to be complementary as each has advantages and limitations. The results further indicate that the lower confidence limit of a benchmark response rate of 10% (BMDL(10) ) could be considered a satisfactory POD when analyzing genotoxicity data using the BMD approach. The models described permit the identification of POD values that could be combined with mode of action analysis to determine whether exposure(s) below a particular level constitutes a significant human risk. Subsequent analyses will expand the number of substances and endpoints investigated, and continue to evaluate the utility of quantitative approaches for analysis of genetic toxicity dose-response data.
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The Evolution, Scientific Reasoning and Use of ICH S2 Guidelines for Genotoxicity Testing of Pharmaceuticals. GLOBAL APPROACH IN SAFETY TESTING 2013. [DOI: 10.1007/978-1-4614-5950-7_6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
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Allsup J, Billinton N, Scott H, Walmsley RM. Applicability domain of the GADD45a reporter assays: non-steroidal anti-inflammatory drugs do not produce misleading genotoxicity results. Toxicol Res (Camb) 2013. [DOI: 10.1039/c3tx50029b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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40
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Naven RT, Greene N, Williams RV. Latest advances in computational genotoxicity prediction. Expert Opin Drug Metab Toxicol 2012; 8:1579-87. [DOI: 10.1517/17425255.2012.724059] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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41
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Luzy AP, Orsini N, Linget JM, Bouvier G. Evaluation of the GADD45α-GFP GreenScreen HC assay for rapid and reliable in vitro early genotoxicity screening. J Appl Toxicol 2012; 33:1303-15. [DOI: 10.1002/jat.2793] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 06/01/2012] [Accepted: 06/01/2012] [Indexed: 12/15/2022]
Affiliation(s)
- Anne-Pascale Luzy
- Galderma R&D, Les Templiers; Route des Colles BP87; F-06902; Sophia-Antipolis; France
| | - Nicolas Orsini
- Galderma R&D, Les Templiers; Route des Colles BP87; F-06902; Sophia-Antipolis; France
| | - Jean-Michel Linget
- Galderma R&D, Les Templiers; Route des Colles BP87; F-06902; Sophia-Antipolis; France
| | - Guy Bouvier
- Galderma R&D, Les Templiers; Route des Colles BP87; F-06902; Sophia-Antipolis; France
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42
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Garcia-Canton C, Anadón A, Meredith C. γH2AX as a novel endpoint to detect DNA damage: applications for the assessment of the in vitro genotoxicity of cigarette smoke. Toxicol In Vitro 2012; 26:1075-86. [PMID: 22735693 DOI: 10.1016/j.tiv.2012.06.006] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 05/17/2012] [Accepted: 06/14/2012] [Indexed: 01/02/2023]
Abstract
Histone H2AX is rapidly phosphorylated to become γH2AX after exposure to DNA-damaging agents that cause double-strand DNA breaks (DSBs). γH2AX can be detected and quantified by numerous methods, giving a direct correlation with the number of DSBs. This relationship has made γH2AX an increasingly utilised endpoint in multiple scientific fields since its discovery in 1998. Applications include its use in pre-clinical drug assessment, as a biomarker of DNA damage and in in vitro mechanistic studies. Here, we review current in vitro regulatory and non-regulatory genotoxicity assays proposing the γH2AX assay as a potential complement to the current test battery. Additionally, we evaluate the use of the γH2AX assay to measure DSBs in vitro in tobacco product testing.
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Affiliation(s)
- Carolina Garcia-Canton
- British American Tobacco, Group Research and Development, Regents Park Road, Southampton, Hampshire SO15 8TL, UK.
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Li Y, Chen DH, Yan J, Chen Y, Mittelstaedt RA, Zhang Y, Biris AS, Heflich RH, Chen T. Genotoxicity of silver nanoparticles evaluated using the Ames test and in vitro micronucleus assay. MUTATION RESEARCH/GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2012; 745:4-10. [DOI: 10.1016/j.mrgentox.2011.11.010] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2011] [Revised: 11/18/2011] [Accepted: 11/18/2011] [Indexed: 04/08/2023]
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Topham CH, Billinton N, Walmsley RM. Nongenotoxic Apoptosis Inducers Do Not Produce Misleading Positive Results in the TK6 Cell-Based GADD45a-GFP Genotoxicity Assay. Toxicol Sci 2012; 128:79-91. [DOI: 10.1093/toxsci/kfs132] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Roemer E, Schorp MK, Piadé JJ, Seeman JI, Leyden DE, Haussmann HJ. Scientific assessment of the use of sugars as cigarette tobacco ingredients: a review of published and other publicly available studies. Crit Rev Toxicol 2012; 42:244-78. [PMID: 22263649 PMCID: PMC3296517 DOI: 10.3109/10408444.2011.650789] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Revised: 11/10/2011] [Accepted: 12/14/2011] [Indexed: 11/13/2022]
Abstract
Sugars, such as sucrose or invert sugar, have been used as tobacco ingredients in American-blend cigarettes to replenish the sugars lost during curing of the Burley component of the blended tobacco in order to maintain a balanced flavor. Chemical-analytical studies of the mainstream smoke of research cigarettes with various sugar application levels revealed that most of the smoke constituents determined did not show any sugar-related changes in yields (per mg nicotine), while ten constituents were found to either increase (formaldehyde, acrolein, 2-butanone, isoprene, benzene, toluene, benzo[k]fluoranthene) or decrease (4-aminobiphenyl, N-nitrosodimethylamine, N-nitrosonornicotine) in a statistically significant manner with increasing sugar application levels. Such constituent yields were modeled into constituent uptake distributions using simulations of nicotine uptake distributions generated on the basis of published nicotine biomonitoring data, which were multiplied by the constituent/nicotine ratios determined in the current analysis. These simulations revealed extensive overlaps for the constituent uptake distributions with and without sugar application. Moreover, the differences in smoke composition did not lead to relevant changes in the activity in in vitro or in vivo assays. The potential impact of using sugars as tobacco ingredients was further assessed in an indirect manner by comparing published data from markets with predominantly American-blend or Virginia-type (no added sugars) cigarettes. No relevant difference was found between these markets for smoking prevalence, intensity, some markers of dependence, nicotine uptake, or mortality from smoking-related lung cancer and chronic obstructive pulmonary disease. In conclusion, thorough examination of the data available suggests that the use of sugars as ingredients in cigarette tobacco does not increase the inherent risk and harm of cigarette smoking.
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Affiliation(s)
- Ewald Roemer
- Philip Morris International Management S.A., Operations Technical Services, Neuchâtel, Switzerland.
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Thomas CE, Will Y. The impact of assay technology as applied to safety assessment in reducing compound attrition in drug discovery. Expert Opin Drug Discov 2012; 7:109-22. [DOI: 10.1517/17460441.2012.651122] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Schuler M, Gollapudi BB, Thybaud V, Kim JH. Need and potential value of the Pig-ain vivo mutation assay-a HESI perspective. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2011; 52:685-689. [PMID: 21976154 DOI: 10.1002/em.20687] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Revised: 08/22/2011] [Accepted: 08/23/2011] [Indexed: 05/31/2023]
Abstract
The Health and Environmental Sciences Institute (HESI), a global branch of the International Life Sciences Institute (ILSI), initiated a project committee entitled "Relevance and Follow-up of Positive Results from In Vitro Genetic Toxicity Testing (IVGT)" with the overall objective of improving the scientific basis for the interpretation of results from genetic toxicology testing. The IVGT committee has also recognized the need to develop follow-up strategies for determining the relevance of in vitro test results to human health, and moving genetic toxicology testing from the sole purpose of hazard identification toward a more quantitative risk assessment approach. In this context, a group of experts evaluated the potential utility of the emerging in vivo mutational assessment model commonly known as the Pig-a gene mutation assay to follow-up positive in vitro genetic toxicology findings and to generate robust dose-response data for quantitative assessment of the in vivo mutagenicity. The IVGT experts participating in this effort represented academia, industry, and government agencies from across the globe and addressed such issues as the optimal sample size and experimental design for generating robust dose-response data. This expert group concluded that the emerging Pig-a gene mutation assay holds great promise as an in vivo mutagenicity assay, either as a stand-alone study or integrated into repeat-dose toxicology studies, and therefore supports further validation of the model.
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Affiliation(s)
- Maik Schuler
- Pfizer Global Research and Development, Drug Safety Research and Development, Groton, Connecticut, USA
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Lynch AM, Giddings A, Custer L, Gleason C, Henwood A, Aylott M, Kenny J. International Pig-a gene mutation assay trial (stage III): results with N-methyl-N-nitrosourea. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2011; 52:699-710. [PMID: 22167885 DOI: 10.1002/em.20691] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
N-methyl-N-nitrosourea (MNU) was evaluated in the in vivo Pig-a mutation assay as part of an International Collaborative Trial to investigate laboratory reproducibility, 28-day study integration, and comparative analysis with micronucleus (MN), comet, and clinical pathology endpoints. Male Sprague Dawley rats were treated for 28 days with doses of 0, 2.5, 5, and 10 mg MNU/kg/day in two independent laboratories, GlaxoSmithKline (GSK) and Bristol Myers Squibb (BMS). Additional studies investigated the low-dose region (<2.5 mg/kg/day). Reticulocytes were evaluated for Pig-a phenotypic mutation, CD59-negative reticulocytes/erythrocytes (RETs(CD592-)/ RBCs(CD592-)) on Days 1, 4, 15, 29, 43, and 57, and for micronucleated reticulocytes (MN-RETs) on Days 4 and 29. Comet analysis was conducted for liver and whole blood, and hematology and clinical chemistry was investigated. Dose-dependent increases in the frequency of RETs(CD592-) and RBCs(CD592-) were observed by Day 15 or 29, respectively. Dose-dependent increases were observed in %MN-RET on Days 4 and 29, and in mean %tail intensity in liver and in blood. Hematology/clinical chemistry data demonstrated bone marrow toxicity. Data comparison between GSK and BMS indicated a high degree of concordance with the Pig-a mutation assay results, consistent with previous observations with MNU and N-ethyl-N-nitrosourea. These data confirm that complementary genotoxicity endpoints can be effectively incorporated into routine toxicology studies, a strategy that can provide information on gene mutation, chromosome damage, and DNA strand breaks in a single repeat dose rodent study. Collectively, this would reduce animal usage while providing valuable genetic toxicity information within the context of other toxicological endpoints.
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Kirkland D. Improvements in the reliability ofin vitrogenotoxicity testing. Expert Opin Drug Metab Toxicol 2011; 7:1513-20. [DOI: 10.1517/17425255.2011.627855] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Wasalathanthri DP, Mani V, Tang CK, Rusling JF. Microfluidic electrochemical array for detection of reactive metabolites formed by cytochrome P450 enzymes. Anal Chem 2011; 83:9499-506. [PMID: 22040095 DOI: 10.1021/ac202269t] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A novel, simple, rapid microfluidic array using bioelectronically driven cytochrome P450 enzyme catalysis for reactive metabolite screening is reported for the first time. The device incorporates an eight-electrode screen-printed carbon array coated with thin films of DNA, [Ru(bpy)(2)(PVP)(10)](ClO(4)) {RuPVP}, and rat liver microsomes (RLM) as enzyme sources. Catalysis features electron donation to cyt P450 reductase in the RLMs and subsequent cyt P450 reduction while flowing an oxygenated substrate solution past sensor electrodes. Metabolites react with DNA in the film if they are able, and damaged DNA is detected by catalytic square wave voltammetry (SWV) utilizing the RuPVP polymer. The microfluidic device was tested for a set of common pollutants known to form DNA-reactive metabolites. Logarithmic turnover rates based on SWV responses gave excellent correlation with the rodent liver TD(50) toxicity metric, supporting the utility of the device for toxicity screening. The microfluidic array gave much better S/N and reproducibility than single-electrode sensors based on similar principles.
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