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Tecchio KB, Alves FDM, Alves JD, Barbosa CDS, Salgado MAR, Santos VJDSVD, Varotti FDP, Campos-Junior PHDA, Viana GHR, Santos FVD. Evaluation of the in vivo acute toxicity and in vitro genotoxicity and mutagenicity of synthetic β-carboline alkaloids with selective cytotoxic activity against ovarian and breast cancer cell lines. MUTATION RESEARCH. GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2024; 899:503808. [PMID: 39326936 DOI: 10.1016/j.mrgentox.2024.503808] [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: 12/14/2023] [Revised: 07/24/2024] [Accepted: 08/06/2024] [Indexed: 09/28/2024]
Abstract
The aim of this study was to evaluate the in vitro cytotoxic, genotoxic, and mutagenic potential and to determine the in silico ADME parameters of two synthetic β-carboline alkaloids developed as prototypes of antitumor agents (NQBio-06 and NQBio-21). Additionally, acute toxicity of the compounds was evaluated in mice. The results from the MTT assay showed that NQBio-06 presented higher cytotoxicity in the ovarian cancer cell line TOV-21 G (IC50 = 2.5 µM, selectivity index = 23.7). NQBio-21 presented an IC50 of 6.9 µM and a selectivity index of 14.5 against MDA-MB-231 breast cancer cells. Comet assay results showed that NQBio-06 did not induce chromosomal breaks in vitro, but NQBio-21 was genotoxic with and without metabolic activation (S9 fraction). Micronucleus assay showed that both compounds were mutagenic. In addition, metabolic activation enhanced this effect in vitro. The in silico predictions showed that the compounds met the criteria set by Lipinski's rules, had strong prediction for intestinal absorption, and were possible substrates for P-glycoprotein. The in vivo results demonstrated that both the compounds exhibited low acute toxicity. These results suggest that the mechanisms underlying the cytotoxicity of NQBio-06 and NQBio-21 are related to DNA damage induction and that the use of S9 enhanced these effects. In vivo analysis showed signs of toxicity after a single administration of the compounds in mice. These findings highlight the potential of β-carboline compounds as sources for the development of new anticancer chemotherapeutic agents.
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Affiliation(s)
- Kimberly Brito Tecchio
- Laboratório de Biologia Celular e Mutagênese (LaBCeM), Universidade Federal de São João del Rei (UFSJ), Campus Centro Oeste, Divinópolis, MG 35501-296, Brazil; Núcleo de Pesquisa em Química Biológica (NQBio), Universidade Federal de São João del Rei (UFSJ), Campus Centro Oeste, Divinópolis, MG 35501-296, Brazil
| | - Fernanda de Moura Alves
- Núcleo de Pesquisa em Química Biológica (NQBio), Universidade Federal de São João del Rei (UFSJ), Campus Centro Oeste, Divinópolis, MG 35501-296, Brazil
| | - Janaina Domingas Alves
- Laboratório de Pesquisa em Reprodução, Departamento de Ciências Naturais, Universidade Federal de São João del Rei, Campus Dom Bosco, São João del-Rei, MG 36301-160, Brazil
| | - Camila de Souza Barbosa
- Núcleo de Pesquisa em Química Biológica (NQBio), Universidade Federal de São João del Rei (UFSJ), Campus Centro Oeste, Divinópolis, MG 35501-296, Brazil
| | - Mariana Alves Rezende Salgado
- Laboratório de Biologia Celular e Mutagênese (LaBCeM), Universidade Federal de São João del Rei (UFSJ), Campus Centro Oeste, Divinópolis, MG 35501-296, Brazil
| | - Vanessa Jaqueline da Silva Vieira Dos Santos
- Laboratório de Biologia Celular e Mutagênese (LaBCeM), Universidade Federal de São João del Rei (UFSJ), Campus Centro Oeste, Divinópolis, MG 35501-296, Brazil; Núcleo de Pesquisa em Química Biológica (NQBio), Universidade Federal de São João del Rei (UFSJ), Campus Centro Oeste, Divinópolis, MG 35501-296, Brazil
| | - Fernando de Pilla Varotti
- Núcleo de Pesquisa em Química Biológica (NQBio), Universidade Federal de São João del Rei (UFSJ), Campus Centro Oeste, Divinópolis, MG 35501-296, Brazil
| | - Paulo Henrique de Almeida Campos-Junior
- Laboratório de Pesquisa em Reprodução, Departamento de Ciências Naturais, Universidade Federal de São João del Rei, Campus Dom Bosco, São João del-Rei, MG 36301-160, Brazil
| | - Gustavo Henrique Ribeiro Viana
- Núcleo de Pesquisa em Química Biológica (NQBio), Universidade Federal de São João del Rei (UFSJ), Campus Centro Oeste, Divinópolis, MG 35501-296, Brazil
| | - Fabio Vieira Dos Santos
- Laboratório de Biologia Celular e Mutagênese (LaBCeM), Universidade Federal de São João del Rei (UFSJ), Campus Centro Oeste, Divinópolis, MG 35501-296, Brazil; Núcleo de Pesquisa em Química Biológica (NQBio), Universidade Federal de São João del Rei (UFSJ), Campus Centro Oeste, Divinópolis, MG 35501-296, Brazil.
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Bak SM, Back SM, Kim DY, Jung S, Jeung NY, Kim NY, Han KH, Kim YB, Lee BS, Park JH, Cho HJ, Lee HG, Ozden O, Kim SK, Park SH. Differential genotoxicity of Polygoni Multiflori in rat and human: insights from Ames test and S9 metabolic activation system. Sci Rep 2024; 14:21433. [PMID: 39271730 PMCID: PMC11399298 DOI: 10.1038/s41598-024-72283-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Accepted: 09/05/2024] [Indexed: 09/15/2024] Open
Abstract
The Ames test is used worldwide to initially screen the mutagenic potential of new chemicals. In the standard Ames test, S. typhimurium strains (TA100, TA98, TA1535, and TA1537) and Escherichia coli (WP2uvrA) are treated with substances with/without cytochrome P450s (CYPs)-induced rat S9 fractions for identifying mutagens and pro-mutagens. However, many substances show completely different toxicity patterns depending on whether the liver S9 fraction belongs to rats or humans. The natural product Polygoni Multiflori Radix (PMR) can also show bacterial reverse mutation, followed by the rat or human liver S9 fraction. While PMR elicits reverse mutations in the TA1537 strain in rat liver S9 but not in human liver S9, this mechanism has not been verified yet. To explain this, the differences in metabolic enzymes compositions commonly observed between rats and humans have been implicated. This study aimed to explore the key factors that cause differences in the genotoxicity of PMR between rat and human liver S9 metabolic enzymes. The results of next-generation sequencing (NGS) analysis showed that both rat and human metabolic enzymes caused similar mutations in TA1537. However, when the metabolic enzymes in each S9 fraction were analyzed using ion mobility tandem mass spectrometry (IM-MS), rat- and human-specific enzymes were identified among the cytochrome (CYP) family, especially aryl hydrocarbon receptor (AHR)-related CYPs. These findings suggest that CYP1A1 isoforms contribute to the mechanism of PMR in the Ames test. Therefore, an in vitro Ames test might be more reliable in predicting genotoxicity for both rodents and humans. This will also help overcome the limitations of laboratory animal-based toxicity evaluations, which provide unreliable results due to interspecies differences between humans and rodents.
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Affiliation(s)
- Su-Min Bak
- Genetic and Epigenetic Toxicology Research Group, Korea Institute of Toxicology, Korea Institute of Toxicology, Daejeon, 34114, Republic of Korea
| | - Seng-Min Back
- Genetic and Epigenetic Toxicology Research Group, Korea Institute of Toxicology, Korea Institute of Toxicology, Daejeon, 34114, Republic of Korea
- College of Pharmacy, Chungnam National University, 9 Daehak-Ro, Yuseong-Gu, Daejeon, 34134, Republic of Korea
| | - Da Yeon Kim
- Genetic and Epigenetic Toxicology Research Group, Korea Institute of Toxicology, Korea Institute of Toxicology, Daejeon, 34114, Republic of Korea
| | - Soyoung Jung
- Genetic and Epigenetic Toxicology Research Group, Korea Institute of Toxicology, Korea Institute of Toxicology, Daejeon, 34114, Republic of Korea
| | - Na-Young Jeung
- Genetic and Epigenetic Toxicology Research Group, Korea Institute of Toxicology, Korea Institute of Toxicology, Daejeon, 34114, Republic of Korea
| | - Nan-Young Kim
- Genetic and Epigenetic Toxicology Research Group, Korea Institute of Toxicology, Korea Institute of Toxicology, Daejeon, 34114, Republic of Korea
| | - Kang-Hyun Han
- Regulatory Toxicology Research Division, Korea Institute of Toxicology, Daejeon, 34114, Republic of Korea
| | - Yong-Bum Kim
- Department of Advanced Toxicology Research, Korea Institute of Toxicology, Daejeon, 34114, Republic of Korea
| | - Byoung-Seok Lee
- Department of Advanced Toxicology Research, Korea Institute of Toxicology, Daejeon, 34114, Republic of Korea
| | - Jun Hong Park
- Herbal Medicine Resources Research Center, Korea Institute of Oriental Medicine, Naju-Si, 58245, South Korea
| | - Hee Jun Cho
- Immunotherapy Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, 34141, Republic of Korea
| | - Hee Gu Lee
- Immunotherapy Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, 34141, Republic of Korea
| | - Ozkan Ozden
- Department of Bioengineering, Faculty of Engineering and Architecture, Kafkas University, 36100, Kars, Turkey
| | - Sang Kyum Kim
- College of Pharmacy, Chungnam National University, 9 Daehak-Ro, Yuseong-Gu, Daejeon, 34134, Republic of Korea.
| | - Seong-Hoon Park
- Genetic and Epigenetic Toxicology Research Group, Korea Institute of Toxicology, Korea Institute of Toxicology, Daejeon, 34114, Republic of Korea.
- Toxicology Mechanism Research Division, Korea Institute of Toxicology, Daejeon, 34114, Republic of Korea.
- Genetic Toxicology Research Group, Toxicology Mechanism Research Division, Korea Institute of Toxicology, 141 Gajeong-Ro, Yuseong-Gu, Daejeon, 34114, Republic of Korea.
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Henneberger L, Huchthausen J, Braasch J, König M, Escher BI. In Vitro Metabolism and p53 Activation of Genotoxic Chemicals: Abiotic CYP Enzyme vs Liver Microsomes. Chem Res Toxicol 2024; 37:1364-1373. [PMID: 38900731 PMCID: PMC11337206 DOI: 10.1021/acs.chemrestox.4c00101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 06/07/2024] [Accepted: 06/12/2024] [Indexed: 06/22/2024]
Abstract
Chemicals often require metabolic activation to become genotoxic. Established test guidelines recommend the use of the rat liver S9 fraction or microsomes to introduce metabolic competence to in vitro cell-based bioassays, but the use of animal-derived components in cell culture raises ethical concerns and may lead to quality issues and reproducibility problems. The aim of the present study was to compare the metabolic activation of cyclophosphamide (CPA) and benzo[a]pyrene (BaP) by induced rat liver microsomes and an abiotic cytochrome P450 (CYP) enzyme based on a biomimetic porphyrine catalyst. For the detection of genotoxic effects, the chemicals were tested in a reporter gene assay targeting the activation of the cellular tumor protein p53. Both chemicals were metabolized by the abiotic CYP enzyme and the microsomes. CPA showed no activation of p53 and low cytotoxicity without metabolic activation, but strong activation of p53 and increased cytotoxicity upon incubation with liver microsomes or abiotic CYP enzyme. The effect concentration causing a 1.5-fold induction of p53 activation was very similar with both metabolization systems (within a factor of 1.5), indicating that genotoxic metabolites were formed at comparable concentrations. BaP also showed low cytotoxicity and no p53 activation without metabolic activation. The activation of p53 was detected for BaP upon incubation with active and inactive microsomes at similar concentrations, indicating experimental artifacts caused by the microsomes or NADPH. The activation of BaP with the abiotic CYP enzyme increased the cytotoxicity of BaP by a factor of 8, but no activation of p53 was detected. The results indicate that abiotic CYP enzymes may present an alternative to rat liver S9 fraction or microsomes for the metabolic activation of test chemicals, which are completely free of animal-derived components. However, an amendment of existing test guidelines would require testing of more chemicals and genotoxicity end points.
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Affiliation(s)
- Luise Henneberger
- Helmholtz
Centre for Environmental Research—UFZ, Department of Cell Toxicology, Permoserstr. 15, 04318 Leipzig, Germany
| | - Julia Huchthausen
- Helmholtz
Centre for Environmental Research—UFZ, Department of Cell Toxicology, Permoserstr. 15, 04318 Leipzig, Germany
| | - Jenny Braasch
- Helmholtz
Centre for Environmental Research—UFZ, Department of Cell Toxicology, Permoserstr. 15, 04318 Leipzig, Germany
| | - Maria König
- Helmholtz
Centre for Environmental Research—UFZ, Department of Cell Toxicology, Permoserstr. 15, 04318 Leipzig, Germany
| | - Beate I. Escher
- Helmholtz
Centre for Environmental Research—UFZ, Department of Cell Toxicology, Permoserstr. 15, 04318 Leipzig, Germany
- Eberhard
Karls University Tübingen, Environmental
Toxicology, Department of Geosciences, 72076 Tübingen, Germany
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Ip BC, Madnick SJ, Zheng S, van Tongeren TCA, Hall SJ, Li H, Martin S, Spriggs S, Carmichael P, Chen W, Ames D, Breitweiser LA, Pence HE, Bowling AJ, Johnson KJ, Cubberley R, Morgan JR, Boekelheide K. Development of a human liver microphysiological coculture system for higher throughput chemical safety assessment. Toxicol Sci 2024; 199:227-245. [PMID: 38335931 PMCID: PMC11131024 DOI: 10.1093/toxsci/kfae018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2024] Open
Abstract
Chemicals in the systemic circulation can undergo hepatic xenobiotic metabolism, generate metabolites, and exhibit altered toxicity compared with their parent compounds. This article describes a 2-chamber liver-organ coculture model in a higher-throughput 96-well format for the determination of toxicity on target tissues in the presence of physiologically relevant human liver metabolism. This 2-chamber system is a hydrogel formed within each well consisting of a central well (target tissue) and an outer ring-shaped trough (human liver tissue). The target tissue chamber can be configured to accommodate a three-dimensional (3D) spheroid-shaped microtissue, or a 2-dimensional (2D) cell monolayer. Culture medium and compounds freely diffuse between the 2 chambers. Human-differentiated HepaRG liver cells are used to form the 3D human liver microtissues, which displayed robust protein expression of liver biomarkers (albumin, asialoglycoprotein receptor, Phase I cytochrome P450 [CYP3A4] enzyme, multidrug resistance-associated protein 2 transporter, and glycogen), and exhibited Phase I/II enzyme activities over the course of 17 days. Histological and ultrastructural analyses confirmed that the HepaRG microtissues presented a differentiated hepatocyte phenotype, including abundant mitochondria, endoplasmic reticulum, and bile canaliculi. Liver microtissue zonation characteristics could be easily modulated by maturation in different media supplements. Furthermore, our proof-of-concept study demonstrated the efficacy of this coculture model in evaluating testosterone-mediated androgen receptor responses in the presence of human liver metabolism. This liver-organ coculture system provides a practical, higher-throughput testing platform for metabolism-dependent bioactivity assessment of drugs/chemicals to better recapitulate the biological effects and potential toxicity of human exposures.
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Affiliation(s)
- Blanche C Ip
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island 02903, USA
- Center for Alternatives to Animals in Testing, Brown University, Providence, Rhode Island 02903, USA
| | - Samantha J Madnick
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island 02903, USA
- Center for Alternatives to Animals in Testing, Brown University, Providence, Rhode Island 02903, USA
| | - Sophia Zheng
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island 02903, USA
| | - Tessa C A van Tongeren
- Division of Toxicology, Wageningen University and Research, 6700 EA Wageningen, The Netherlands
| | - Susan J Hall
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island 02903, USA
| | - Hui Li
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island 02903, USA
| | - Suzanne Martin
- Unilever, Safety and Environmental Assurance Centre, Colworth Science Park, Sharnbrook, MK44 1LQ Bedfordshire, United Kingdom
| | - Sandrine Spriggs
- Unilever, Safety and Environmental Assurance Centre, Colworth Science Park, Sharnbrook, MK44 1LQ Bedfordshire, United Kingdom
| | - Paul Carmichael
- Unilever, Safety and Environmental Assurance Centre, Colworth Science Park, Sharnbrook, MK44 1LQ Bedfordshire, United Kingdom
| | - Wei Chen
- Corteva, Inc, Indianapolis, Indiana 46268, USA
| | - David Ames
- Corteva, Inc, Indianapolis, Indiana 46268, USA
| | | | | | | | | | - Richard Cubberley
- Unilever, Safety and Environmental Assurance Centre, Colworth Science Park, Sharnbrook, MK44 1LQ Bedfordshire, United Kingdom
| | - Jeffrey R Morgan
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island 02903, USA
- Center for Alternatives to Animals in Testing, Brown University, Providence, Rhode Island 02903, USA
| | - Kim Boekelheide
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island 02903, USA
- Center for Alternatives to Animals in Testing, Brown University, Providence, Rhode Island 02903, USA
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Huchthausen J, Braasch J, Escher BI, König M, Henneberger L. Effects of Chemicals in Reporter Gene Bioassays with Different Metabolic Activities Compared to Baseline Toxicity. Chem Res Toxicol 2024; 37:744-756. [PMID: 38652132 PMCID: PMC11110108 DOI: 10.1021/acs.chemrestox.4c00017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 04/05/2024] [Accepted: 04/09/2024] [Indexed: 04/25/2024]
Abstract
High-throughput cell-based bioassays are used for chemical screening and risk assessment. Chemical transformation processes caused by abiotic degradation or metabolization can reduce the chemical concentration or, in some cases, lead to the formation of more toxic transformation products. Unaccounted loss processes may falsify the bioassay results. Capturing the formation and effects of transformation products is important for relating the in vitro effects to in vivo. Reporter gene cell lines are believed to have low metabolic activity, but inducibility of cytochrome P450 (CYP) enzymes has been reported. Baseline toxicity is the minimal toxicity a chemical can have and is caused by the incorporation of the chemical into cell membranes. In the present study, we improved an existing baseline toxicity model based on a newly defined critical membrane burden derived from freely dissolved effect concentrations, which are directly related to the membrane concentration. Experimental effect concentrations of 94 chemicals in three bioassays (AREc32, ARE-bla and GR-bla) were compared with baseline toxicity by calculating the toxic ratio (TR). CYP activities of all cell lines were determined by using fluorescence-based assays. Only ARE-bla showed a low basal CYP activity and inducibility and AREc32 showed a low inducibility. Overall cytotoxicity was similar in all three assays despite the different metabolic activities indicating that chemical metabolism is not relevant for the cytotoxicity of the tested chemicals in these assays. Up to 28 chemicals showed specific cytotoxicity with TR > 10 in the bioassays, but baseline toxicity could explain the effects of the majority of the remaining chemicals. Seven chemicals showed TR < 0.1 indicating inaccurate physicochemical properties or experimental artifacts like chemical precipitation, volatilization, degradation, or other loss processes during the in vitro bioassay. The new baseline model can be used not only to identify specific cytotoxicity mechanisms but also to identify potential problems in the experimental performance or evaluation of the bioassay and thus improve the quality of the bioassay data.
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Affiliation(s)
- Julia Huchthausen
- Department
of Cell Toxicology, Helmholtz Centre for
Environmental Research − UFZ, Permoserstr. 15, 04318 Leipzig, Germany
| | - Jenny Braasch
- Department
of Cell Toxicology, Helmholtz Centre for
Environmental Research − UFZ, Permoserstr. 15, 04318 Leipzig, Germany
| | - Beate I. Escher
- Department
of Cell Toxicology, Helmholtz Centre for
Environmental Research − UFZ, Permoserstr. 15, 04318 Leipzig, Germany
- Environmental
Toxicology, Department of Geosciences, Eberhard
Karls University Tübingen, 72076 Tübingen, Germany
| | - Maria König
- Department
of Cell Toxicology, Helmholtz Centre for
Environmental Research − UFZ, Permoserstr. 15, 04318 Leipzig, Germany
| | - Luise Henneberger
- Department
of Cell Toxicology, Helmholtz Centre for
Environmental Research − UFZ, Permoserstr. 15, 04318 Leipzig, Germany
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Yadav V, Fuentes JL, Krishnan A, Singh N, Vohora D. Guidance for the use and interpretation of assays for monitoring anti-genotoxicity. Life Sci 2024; 337:122341. [PMID: 38101613 DOI: 10.1016/j.lfs.2023.122341] [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: 08/03/2023] [Revised: 12/05/2023] [Accepted: 12/06/2023] [Indexed: 12/17/2023]
Abstract
Since DNA damage can occur spontaneously or be produced by the environmental genotoxins in living cells, it is important to investigate compounds that can reverse or protect DNA damage. An appropriate methodology is essential for the responsive identification of protection offered against DNA damage. This review includes information on the current state of knowledge on prokaryotic cell-based assays (SOS chromotest, umu test, vitotox assay) and cytogenetic techniques (micronucleus assay, chromosome aberration test and sister chromatid exchange assay) with an emphasis on the possibility to explore genoprotective compounds. Throughout the last decade, studies have extrapolated the scientific methodologies utilized for genotoxicity to assess genoprotective compounds. Therefore, shortcomings of genotoxicity studies are also mirrored in antigenotoxicity studies. While regulatory authorities around the world (OECD, US-EPA and ICH) continue to update diverse genotoxic assay strategies, there are still no clear guidelines/approaches for efficient experimental design to screen genoprotective compounds. As a consequence, non-synergetic and inconsistent implementation of the test method by the researchers to execute such simulations has been adopted, which inevitably results in unreliable findings. The review has made the first attempt to collect various facets of experimentally verified approaches for evaluating genoprotective compounds, as well as to acknowledge potential significance and constraints, and further focus on the assessment of end points which are required to validate such action. Henceforth, the review makes an incredible commitment by permitting readers to equate several components of their test arrangement with the provided simplified information, allowing the selection of convenient technique for the predefined compound from a central repository.
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Affiliation(s)
- Vaishali Yadav
- Neurobehavioral Pharmacology Laboratory, Department of Pharmacology, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi 110062, India
| | - Jorge L Fuentes
- School of Biology, Science Faculty, Industrial University of Santander, Bucaramanga 680002, Santander, Colombia
| | - Anuja Krishnan
- Department of Molecular Medicine, School of Interdisciplinary Science and Technology, Jamia Hamdard, New Delhi 110062, India
| | - Neenu Singh
- Leicester School of Allied Health Sciences, Faculty of Health & Life Sciences, De Montfort University, The Gateway, Leicester LE1 9BH, UK
| | - Divya Vohora
- Neurobehavioral Pharmacology Laboratory, Department of Pharmacology, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi 110062, India.
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Hopperstad K, Deisenroth C. Development of a bioprinter-based method for incorporating metabolic competence into high-throughput in vitro assays. FRONTIERS IN TOXICOLOGY 2023; 5:1196245. [PMID: 37215384 PMCID: PMC10192685 DOI: 10.3389/ftox.2023.1196245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 04/21/2023] [Indexed: 05/24/2023] Open
Abstract
The acceptance and use of in vitro data for hazard identification, prioritization, and risk evaluation is partly limited by uncertainties associated with xenobiotic metabolism. The lack of biotransformation capabilities of many in vitro systems may under- or overestimate the hazard of compounds that are metabolized to more or less active metabolites in vivo. One approach to retrofitting existing bioassays with metabolic competence is the lid-based Alginate Immobilization of Metabolic Enzymes (AIME) method, which adds hepatic metabolism to conventional high-throughput screening platforms. Here, limitations of the lid-based AIME method were addressed by incorporating bioprinting, which involved depositing S9-encapsulated microspheres into standard 384-well plates with requisite cofactors for phase I and II hepatic metabolism. Objectives of this study included: 1) compare the lid-based and AIME bioprinting methods by assessing the enzymatic activity of a common cytochrome P450 (CYP) enzyme, 2) use biochemical assays with the bioprinting method to characterize additional measures of phase I and II metabolic activity, and 3) evaluate the bioprinting method by screening 25 chemicals of known metabolism-dependent bioactivity in the VM7Luc estrogen receptor transactivation (ERTA) assay. A comparison of the two methods revealed comparable precision and dynamic range. Activity of additional CYP enzymes and glucuronidation was observed using the AIME bioprinting method. The ERTA experiment identified 19/21 ER-active test chemicals, 14 of which were concordant with expected biotransformation effects (73.7%). Additional refinement of the AIME bioprinting method has the potential to expand high-throughput screening capabilities in a robust, accessible manner to incorporate in vitro metabolic competence.
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Reichstein IS, König M, Wojtysiak N, Escher BI, Henneberger L, Behnisch P, Besselink H, Thalmann B, Colas J, Hörchner S, Hollert H, Schiwy A. Replacing animal-derived components in in vitro test guidelines OECD 455 and 487. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 868:161454. [PMID: 36638987 DOI: 10.1016/j.scitotenv.2023.161454] [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: 10/25/2022] [Revised: 12/23/2022] [Accepted: 01/03/2023] [Indexed: 06/17/2023]
Abstract
The evaluation of single substances or environmental samples for their genotoxic or estrogenic potential is highly relevant for human- and environment-related risk assessment. To examine the effects on a mechanism-specific level, standardized cell-based in vitro methods are widely applied. However, these methods include animal-derived components like fetal bovine serum (FBS) or rat-derived liver homogenate fractions (S9-mixes), which are a source of variability, reduced assay reproducibility and ethical concerns. In our study, we evaluated the adaptation of the cell-based in vitro OECD test guidelines TG 487 (assessment of genotoxicity) and TG 455 (detection of estrogenic activity) to an animal-component-free methodology. Firstly, the human cell lines A549 (for OECD TG 487), ERα-CALUX® and GeneBLAzer™ ERα-UAS-bla GripTite™ (for OECD TG 455) were investigated for growth in a chemically defined medium without the addition of FBS. Secondly, the biotechnological S9-mix ewoS9R was implemented in comparison to the induced rat liver S9 to simulate in vivo metabolism capacities in both OECD test guidelines. As a model compound, Benzo[a]pyrene was used due to its increased genotoxicity and endocrine activity after metabolization. The metabolization of Benzo[a]Pyrene by S9-mixes was examined via chemical analysis. All cell lines (A549, ERα-CALUX® and GeneBLAzer™ Erα-UAS-bla GripTite™) were successfully cultivated in chemically defined media without FBS. The micronucleus assay could not be conducted in chemically defined medium due to formation of cell clusters. The methods for endocrine activity assessment could be conducted in chemically defined media or reduced FBS content, but with decreased assay sensitivity. The biotechnological ewoS9R showed potential to replace rat liver S9 in the micronucleus in FBS-medium with A549 cells and in the ERα-CALUX® assay in FBS- and chemically defined medium. Our study showed promising steps towards an animal-component free toxicity testing. After further improvements, the new methodology could lead to more reproducible and reliable results for risk assessment.
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Affiliation(s)
- Inska S Reichstein
- Department of Evolutionary Ecology and Environmental Toxicology, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Maria König
- Department of Cell Toxicology, Helmholtz Centre for Environmental Research, Leipzig, Germany
| | - Niklas Wojtysiak
- Department of Cell Toxicology, Helmholtz Centre for Environmental Research, Leipzig, Germany
| | - Beate I Escher
- Department of Cell Toxicology, Helmholtz Centre for Environmental Research, Leipzig, Germany; Environmental Toxicology, Center for Applied Geosciences, Eberhard Karls University Tübingen, Germany
| | - Luise Henneberger
- Department of Cell Toxicology, Helmholtz Centre for Environmental Research, Leipzig, Germany
| | | | | | | | - Julien Colas
- Department of Evolutionary Ecology and Environmental Toxicology, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Sarah Hörchner
- Department of Evolutionary Ecology and Environmental Toxicology, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Henner Hollert
- Department of Evolutionary Ecology and Environmental Toxicology, Goethe University Frankfurt, Frankfurt am Main, Germany; Department Environmental Media Related Ecotoxicology, Fraunhofer IME, Schmallenberg, Germany.
| | - Andreas Schiwy
- Department of Evolutionary Ecology and Environmental Toxicology, Goethe University Frankfurt, Frankfurt am Main, Germany; Department Environmental Media Related Ecotoxicology, Fraunhofer IME, Schmallenberg, Germany.
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9
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Kelty J, Kovalchuk N, Uwimana E, Yin L, Ding X, Van Winkle L. In vitro airway models from mice, rhesus macaques, and humans maintain species differences in xenobiotic metabolism and cellular responses to naphthalene. Am J Physiol Lung Cell Mol Physiol 2022; 323:L308-L328. [PMID: 35853015 PMCID: PMC9423729 DOI: 10.1152/ajplung.00349.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 04/04/2022] [Accepted: 07/01/2022] [Indexed: 11/22/2022] Open
Abstract
The translational value of high-throughput toxicity testing will depend on pharmacokinetic validation. Yet, popular in vitro airway epithelia models were optimized for structure and mucociliary function without considering the bioactivation or detoxification capabilities of lung-specific enzymes. This study evaluated xenobiotic metabolism maintenance within differentiated air-liquid interface (ALI) airway epithelial cell cultures (human bronchial; human, rhesus, and mouse tracheal), isolated airway epithelial cells (human, rhesus, and mouse tracheal; rhesus bronchial), and ex vivo microdissected airways (rhesus and mouse) by measuring gene expression, glutathione content, and naphthalene metabolism. Glutathione levels and detoxification gene transcripts were measured after 1-h exposure to 80 µM naphthalene (a bioactivated toxicant) or reactive naphthoquinone metabolites. Glutathione and glutathione-related enzyme transcript levels were maintained in ALI cultures from all species relative to source tissues, while cytochrome P450 monooxygenase gene expression declined. Notable species differences among the models included a 40-fold lower total glutathione content for mouse ALI trachea cells relative to human and rhesus; a higher rate of naphthalene metabolism in mouse ALI cultures for naphthalene-glutathione formation (100-fold over rhesus) and naphthalene-dihydrodiol production (10-fold over human); and opposite effects of 1,2-naphthoquinone exposure in some models-glutathione was depleted in rhesus tissue but rose in mouse ALI samples. The responses of an immortalized bronchial cell line to naphthalene and naphthoquinones were inconsistent with those of human ALI cultures. These findings of preserved species differences and the altered balance of phase I and phase II xenobiotic metabolism among the characterized in vitro models should be considered for future pulmonary toxicity testing.
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Affiliation(s)
- Jacklyn Kelty
- Department of Anatomy, Physiology and Cell Biology, Center for Comparative Respiratory Biology and Medicine, School of Veterinary Medicine and Center for Health and the Environment, University of California at Davis, Davis, California
| | - Nataliia Kovalchuk
- Pharmacology and Toxicology Department, College of Pharmacy, University of Arizona, Tucson, Arizona
| | - Eric Uwimana
- Pharmacology and Toxicology Department, College of Pharmacy, University of Arizona, Tucson, Arizona
| | - Lei Yin
- Pharmacology and Toxicology Department, College of Pharmacy, University of Arizona, Tucson, Arizona
| | - Xinxin Ding
- Pharmacology and Toxicology Department, College of Pharmacy, University of Arizona, Tucson, Arizona
| | - Laura Van Winkle
- Department of Anatomy, Physiology and Cell Biology, Center for Comparative Respiratory Biology and Medicine, School of Veterinary Medicine and Center for Health and the Environment, University of California at Davis, Davis, California
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10
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Lim HK, Hughes CO, Lim MJS, Li JJ, Rakshit M, Yeo C, Chng KR, Li A, Chan JSH, Ng KW, Leavesley DI, Smith BPC. Development of reconstructed intestinal micronucleus cytome (RICyt) assay in 3D human gut model for genotoxicity assessment of orally ingested substances. Arch Toxicol 2022; 96:1455-1471. [PMID: 35226136 PMCID: PMC9013689 DOI: 10.1007/s00204-022-03228-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 01/12/2022] [Indexed: 11/30/2022]
Abstract
The micronucleus (MN) assay is widely used as part of a battery of tests applied to evaluate the genotoxic potential of chemicals, including new food additives and novel food ingredients. Micronucleus assays typically utilise homogenous in vitro cell lines which poorly recapitulate the physiology, biochemistry and genomic events in the gut, the site of first contact for ingested materials. Here we have adapted and validated the MN endpoint assay protocol for use with complex 3D reconstructed intestinal microtissues; we have named this new protocol the reconstructed intestine micronucleus cytome (RICyt) assay. Our data suggest the commercial 3D microtissues replicate the physiological, biochemical and genomic responses of native human small intestine to exogenous compounds. Tissues were shown to maintain log-phase proliferation throughout the period of exposure and expressed low background MN. Analysis using the RICyt assay protocol revealed the presence of diverse cell types and nuclear anomalies (cytome) in addition to MN, indicating evidence for comprehensive DNA damage and mode(s) of cell death reported by the assay. The assay correctly identified and discriminated direct-acting clastogen, aneugen and clastogen requiring exogenous metabolic activation, and a non-genotoxic chemical. We are confident that the genotoxic response in the 3D microtissues more closely resembles the native tissues due to the inherent tissue architecture, surface area, barrier effects and tissue matrix interactions. This proof-of-concept study highlights the RICyt MN cytome assay in 3D reconstructed intestinal microtissues is a promising tool for applications in predictive toxicology.
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Affiliation(s)
- Hui Kheng Lim
- Innovations in Food and Chemical Safety (IFCS) Programme, Agency for Science, Technology and Research, Singapore, Singapore.
- Skin Research Institute of Singapore (SRIS), Agency for Science, Technology and Research, Singapore, Singapore.
- Future Ready Food Safety Hub (a Joint Initiative of A*STAR, SFA and NTU), Nanyang Technological University, Singapore, Singapore.
| | - Christopher Owen Hughes
- Innovations in Food and Chemical Safety (IFCS) Programme, Agency for Science, Technology and Research, Singapore, Singapore
- Skin Research Institute of Singapore (SRIS), Agency for Science, Technology and Research, Singapore, Singapore
| | - Michelle Jing Sin Lim
- Innovations in Food and Chemical Safety (IFCS) Programme, Agency for Science, Technology and Research, Singapore, Singapore
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research, Singapore, Singapore
| | - Jia'En Jasmine Li
- National Centre for Food Science, Singapore Food Agency, Singapore, Singapore
| | - Moumita Rakshit
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Calvin Yeo
- National Centre for Food Science, Singapore Food Agency, Singapore, Singapore
| | - Kern Rei Chng
- National Centre for Food Science, Singapore Food Agency, Singapore, Singapore
| | - Angela Li
- National Centre for Food Science, Singapore Food Agency, Singapore, Singapore
| | | | - Kee Woei Ng
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
- Environmental Chemistry and Materials Centre, Nanyang Environment and Water Research Institute, Singapore, Singapore
- Harvard T. H. Chan School of Public Health, Harvard University, Cambridge, USA
| | - David Ian Leavesley
- Innovations in Food and Chemical Safety (IFCS) Programme, Agency for Science, Technology and Research, Singapore, Singapore
- Skin Research Institute of Singapore (SRIS), Agency for Science, Technology and Research, Singapore, Singapore
| | - Benjamin Paul Chapman Smith
- Innovations in Food and Chemical Safety (IFCS) Programme, Agency for Science, Technology and Research, Singapore, Singapore
- Future Ready Food Safety Hub (a Joint Initiative of A*STAR, SFA and NTU), Nanyang Technological University, Singapore, Singapore
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research, Singapore, Singapore
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11
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Ooka M, Zhao J, Shah P, Travers J, Klumpp-Thomas C, Xu X, Huang R, Ferguson S, Witt KL, Smith-Roe SL, Simeonov A, Xia M. Identification of environmental chemicals that activate p53 signaling after in vitro metabolic activation. Arch Toxicol 2022; 96:1975-1987. [PMID: 35435491 PMCID: PMC9151520 DOI: 10.1007/s00204-022-03291-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Accepted: 03/24/2022] [Indexed: 12/11/2022]
Abstract
Currently, approximately 80,000 chemicals are used in commerce. Most have little-to-no toxicity information. The U.S. Toxicology in the 21st Century (Tox21) program has conducted a battery of in vitro assays using a quantitative high-throughput screening (qHTS) platform to gain toxicity information on environmental chemicals. Due to technical challenges, standard methods for providing xenobiotic metabolism could not be applied to qHTS assays. To address this limitation, we screened the Tox21 10,000-compound (10K) library, with concentrations ranging from 2.8 nM to 92 µM, using a p53 beta-lactamase reporter gene assay (p53-bla) alone or with rat liver microsomes (RLM) or human liver microsomes (HLM) supplemented with NADPH, to identify compounds that induce p53 signaling after biotransformation. Two hundred and seventy-eight compounds were identified as active under any of these three conditions. Of these 278 compounds, 73 gave more potent responses in the p53-bla assay with RLM, and 2 were more potent in the p53-bla assay with HLM compared with the responses they generated in the p53-bla assay without microsomes. To confirm the role of metabolism in the differential responses, we re-tested these 75 compounds in the absence of NADPH or with heat-attenuated microsomes. Forty-four compounds treated with RLM, but none with HLM, became less potent under these conditions, confirming the role of RLM in metabolic activation. Further evidence of biotransformation was obtained by measuring the half-life of the parent compounds in the presence of microsomes. Together, the data support the use of RLM in qHTS for identifying chemicals requiring biotransformation to induce biological responses.
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Affiliation(s)
- Masato Ooka
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | - Jinghua Zhao
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | - Pranav Shah
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | - Jameson Travers
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | - Carleen Klumpp-Thomas
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | - Xin Xu
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | - Ruili Huang
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | - Stephen Ferguson
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA
| | - Kristine L Witt
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA
| | - Stephanie L Smith-Roe
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA
| | - Anton Simeonov
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | - Menghang Xia
- National Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Rockville, MD, 20850, USA.
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12
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Comparative Analysis of Transcriptional Responses to Genotoxic and Non-Genotoxic Agents in the Blood Cell Model TK6 and the Liver Model HepaRG. Int J Mol Sci 2022; 23:ijms23073420. [PMID: 35408779 PMCID: PMC8998745 DOI: 10.3390/ijms23073420] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/16/2022] [Accepted: 03/18/2022] [Indexed: 01/27/2023] Open
Abstract
Transcript signatures are a promising approach to identify and classify genotoxic and non-genotoxic compounds and are of interest as biomarkers or for future regulatory application. Not much data, however, is yet available about the concordance of transcriptional responses in different cell types or tissues. Here, we analyzed transcriptomic responses to selected genotoxic food contaminants in the human p53-competent lymphoblastoid cell line TK6 using RNA sequencing. Responses to treatment with five genotoxins, as well as with four non-genotoxic liver toxicants, were compared with previously published gene expression data from the human liver cell model HepaRG. A significant overlap of the transcriptomic changes upon genotoxic stress was detectable in TK6 cells, whereas the comparison with the HepaRG model revealed considerable differences, which was confirmed by bioinformatic data mining for cellular upstream regulators or pathways. Taken together, the study presents a transcriptomic signature for genotoxin exposure in the human TK6 blood cell model. The data demonstrate that responses in different cell models have considerable variations. Detection of a transcriptomic genotoxin signature in blood cells indicates that gene expression analyses of blood samples might be a valuable approach to also estimate responses to toxic exposure in target organs such as the liver.
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13
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Nie J, Zhang Y, Ning L, Yan Z, Duan L, Xi H, Niu Q, Zhang Q. Phosphorylation of p53 by Cdk5 contributes to benzo[a]pyrene-induced neuronal apoptosis. ENVIRONMENTAL TOXICOLOGY 2022; 37:17-27. [PMID: 34529316 DOI: 10.1002/tox.23374] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 08/18/2021] [Accepted: 09/06/2021] [Indexed: 06/13/2023]
Abstract
Benzo[a]pyrene (B[a]P) is a ubiquitous carcinogenic pollutant in the environment, however, the potential neurotoxic effects of B[a]P has not been elucidated clearly. In the present study, we explored the potential involvement of p53 phosphorylation by Cdk5 in B[a]P-induced neuronal apoptosis at both in vitro and in vivo settings. For in vitro studies, primary cortical neurons isolated from the brains of Sprague Dawley (SD) rat pup were exposed to 0, 10, 20, and 40 μM of B[a]P for 12, 24, or 48 h. For in vivo studies, SD rats were injected intraperitoneally with 0, 1.0, 2.5, and 6.25 mg/kg of B[a]P every other day for 1, 2, or 3 months. Our results demonstrated that exposure to B[a]P caused a dose- and a time-dependent increase in neuronal apoptotic ratio in both in vitro and in vivo studies. There was also a dose- and a time-dependent upregulation of p35, p25, Cdk5, and phosphorylated p53 at Ser15 after B[a]P exposure. In order to explore whether B[a]P-induced increased neuronal apoptosis was through Cdk5/p53 pathway, roscovitine, a specific Cdk5 inhibitor, was applied to pretreat neurons prior to B[a]P exposure. The results showed that pretreatment of neurons with roscovitine partially rescued cells from B[a]P-induced apoptosis, and alleviated B[a]P-induced upregulation of phosphorylated p53 at Ser15. Our results suggest that Cdk5/p53 signaling pathway may be involved in B[a]P-induced neuronal apoptosis, which will provide information to further elucidate the molecular mechanisms of B[a]P-induced neurotoxicity.
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Affiliation(s)
- Jisheng Nie
- Department of Occupational Health, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, China
| | - Yu Zhang
- Department of Occupational Health, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, China
| | - Lijun Ning
- Department of Occupational Health, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, China
| | - Zhiwei Yan
- Department of Occupational Health, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, China
| | - Lei Duan
- Department of Occupational Health, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, China
| | - Huaxing Xi
- Department of Occupational Health, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, China
| | - Qiao Niu
- Department of Occupational Health, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, China
| | - Qunwei Zhang
- Department of Environmental and Occupational Health Sciences, University of Louisville, Louisville, Kentucky, USA
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14
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Deisenroth C, DeGroot DE, Zurlinden T, Eicher A, McCord J, Lee MY, Carmichael P, Thomas RS. The Alginate Immobilization of Metabolic Enzymes Platform Retrofits an Estrogen Receptor Transactivation Assay With Metabolic Competence. Toxicol Sci 2021; 178:281-301. [PMID: 32991717 DOI: 10.1093/toxsci/kfaa147] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The U.S. EPA Endocrine Disruptor Screening Program utilizes data across the ToxCast/Tox21 high-throughput screening (HTS) programs to evaluate the biological effects of potential endocrine active substances. A potential limitation to the use of in vitro assay data in regulatory decision-making is the lack of coverage for xenobiotic metabolic processes. Both hepatic- and peripheral-tissue metabolism can yield metabolites that exhibit greater activity than the parent compound (bioactivation) or are inactive (bioinactivation) for a given biological target. Interpretation of biological effect data for both putative endocrine active substances, as well as other chemicals, screened in HTS assays may benefit from the addition of xenobiotic metabolic capabilities to decrease the uncertainty in predicting potential hazards to human health. The objective of this study was to develop an approach to retrofit existing HTS assays with hepatic metabolism. The Alginate Immobilization of Metabolic Enzymes (AIME) platform encapsulates hepatic S9 fractions in alginate microspheres attached to 96-well peg lids. Functional characterization across a panel of reference substrates for phase I cytochrome P450 enzymes revealed substrate depletion with expected metabolite accumulation. Performance of the AIME method in the VM7Luc estrogen receptor transactivation assay was evaluated across 15 reference chemicals and 48 test chemicals that yield metabolites previously identified as estrogen receptor active or inactive. The results demonstrate the utility of applying the AIME method for identification of false-positive and false-negative target assay effects, reprioritization of hazard based on metabolism-dependent bioactivity, and enhanced in vivo concordance with the rodent uterotrophic bioassay. Integration of the AIME metabolism method may prove useful for future biochemical and cell-based HTS applications.
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Affiliation(s)
- Chad Deisenroth
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - Danica E DeGroot
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - Todd Zurlinden
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - Andrew Eicher
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - James McCord
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - Mi-Young Lee
- Safety and Environmental Assurance Centre, Unilever, Colworth Science, Park, Bedford, Sharnbrook MK44 1LQ, UK
| | - Paul Carmichael
- Safety and Environmental Assurance Centre, Unilever, Colworth Science, Park, Bedford, Sharnbrook MK44 1LQ, UK
| | - Russell S Thomas
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711
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15
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Schultz F, Osuji OF, Nguyen A, Anywar G, Scheel JR, Caljon G, Pieters L, Garbe LA. Pharmacological Assessment of the Antiprotozoal Activity, Cytotoxicity and Genotoxicity of Medicinal Plants Used in the Treatment of Malaria in the Greater Mpigi Region in Uganda. Front Pharmacol 2021; 12:678535. [PMID: 34276369 PMCID: PMC8278201 DOI: 10.3389/fphar.2021.678535] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 05/21/2021] [Indexed: 11/13/2022] Open
Abstract
We investigated the potential antimalarial and toxicological effects of 16 medicinal plants frequently used by traditional healers to treat malaria, fever, and related disorders in the Greater Mpigi region in Uganda. Species studied were Albizia coriaria, Cassine buchananii, Combretum molle, Erythrina abyssinica, Ficus saussureana, Harungana madagascariensis, Leucas calostachys, Microgramma lycopodioides, Morella kandtiana, Plectranthus hadiensis, Securidaca longipedunculata, Sesamum calycinum subsp. angustifolium, Solanum aculeastrum, Toddalia asiatica, Warburgia ugandensis, and Zanthoxylum chalybeum. In addition, the traditional healers indicated that P. hadiensis is used as a ritual plant to boost fertility and prepare young women and teenagers for motherhood in some Ugandan communities where a high incidence of rapidly growing large breast masses in young female patients was observed (not necessarily breast cancer). We present results from various in vitro experiments performed with 56 different plant extracts, namely, 1) an initial assessment of the 16 species regarding their traditional use in the treatment of malaria by identifying promising plant extract candidates using a heme biocrystallization inhibition library screen; 2) follow-up investigations of antiprotozoal effects of the most bioactive crude extracts against chloroquine-resistant P. falciparum K1; 3) a cytotoxicity counterscreen against human MRC-5SV2 lung fibroblasts; 4) a genotoxicity evaluation of the extract library without and with metabolic bioactivation with human S9 liver fraction; and 5) an assessment of the mutagenicity of the ritual plant P. hadiensis. A total of seven extracts from five plant species were selected for antiplasmodial follow-up investigations based on their hemozoin formation inhibition activity in the heme biocrystallization assay. Among other extracts, an ethyl acetate extract of L. calostachys leaves exhibited antiplasmodial activity against P. falciparum K1 (IC50 value: 5.7 µg/ml), which was further characterized with a selectivity index of 2.6 (CC50 value: 14.7 µg/ml). The experiments for assessment of potential procarcinogenic properties of plant extracts via evaluation of in vitro mutagenicity and genotoxicity indicated that few extracts cause mutations. The species T. asiatica showed the most significant genotoxic effects on both bacterial test strains (without metabolic bioactivation at a concentration of 500 µg/plate). However, none of the mutagenic extracts from the experiments without metabolic bioactivation retained their genotoxic activity after metabolic bioactivation of the plant extract library through pre-incubation with human S9 liver fraction. While this study did not show that P. hadiensis has genotoxic properties, it did provide early stage support for the therapeutic use of the medicinal plants from the Greater Mpigi region.
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Affiliation(s)
- Fabien Schultz
- Institute of Biotechnology, Faculty III—Process Sciences, Technical University of Berlin, Berlin, Germany
- Department of Agriculture and Food Sciences, Neubrandenburg University of Applied Sciences, Neubrandenburg, Germany
| | - Ogechi Favour Osuji
- Department of Agriculture and Food Sciences, Neubrandenburg University of Applied Sciences, Neubrandenburg, Germany
| | - Anh Nguyen
- Department of Agriculture and Food Sciences, Neubrandenburg University of Applied Sciences, Neubrandenburg, Germany
| | - Godwin Anywar
- Department of Plant Sciences, Microbiology and Biotechnology, Makerere University, Kampala, Uganda
| | - John R. Scheel
- Department of Global Health, University of Washington, Seattle, WA, United States
- Department of Radiology, University of Washington, Seattle, WA, United States
| | - Guy Caljon
- Laboratory of Microbiology, Parasitology and Hygiene, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Antwerp, Belgium
| | - Luc Pieters
- Natural Products & Food Research and Analysis (NatuRA), Department of Pharmaceutical Sciences, University of Antwerp, Antwerp, Belgium
| | - Leif-Alexander Garbe
- Department of Agriculture and Food Sciences, Neubrandenburg University of Applied Sciences, Neubrandenburg, Germany
- ZELT—Neubrandenburg Center for Nutrition and Food Technology gGmbH, Neubrandenburg, Germany
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16
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Maksimova V, Shalginskikh N, Vlasova O, Usalka O, Beizer A, Bugaeva P, Fedorov D, Lizogub O, Lesovaya E, Katz R, Belitsky G, Kirsanov K, Yakubovskaya M. HeLa TI cell-based assay as a new approach to screen for chemicals able to reactivate the expression of epigenetically silenced genes. PLoS One 2021; 16:e0252504. [PMID: 34115770 PMCID: PMC8195432 DOI: 10.1371/journal.pone.0252504] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 05/17/2021] [Indexed: 11/18/2022] Open
Abstract
Chemicals reactivating epigenetically silenced genes target diverse classes of enzymes, including DNMTs, HDACs, HMTs and BET protein family members. They can strongly influence the expression of genes and endogenous retroviral elements with concomitant dsRNA synthesis and massive transcription of LTRs. Chemicals reactivating gene expression may cause both beneficial effects in cancer cells and may be hazardous by promoting carcinogenesis. Among chemicals used in medicine and commerce, only a small fraction has been studied with respect to their influence on epigenetic silencing. Screening of chemicals reactivating silent genes requires adequate systems mimicking whole-genome processes. We used a HeLa TSA-inducible cell population (HeLa TI cells) obtained by retroviral infection of a GFP-containing vector followed by several rounds of cell sorting for screening purposes. Previously, the details of GFP epigenetic silencing in HeLa TI cells were thoroughly described. Herein, we show that the epigenetically repressed gene GFP is reactivated by 15 agents, including HDAC inhibitors–vorinostat, sodium butyrate, valproic acid, depsipeptide, pomiferin, and entinostat; DNMT inhibitors–decitabine, 5-azacytidine, RG108; HMT inhibitors–UNC0638, BIX01294, DZNep; a chromatin remodeler–curaxin CBL0137; and BET inhibitors–JQ-1 and JQ-35. We demonstrate that combinations of epigenetic modulators caused a significant increase in cell number with reactivated GFP compared to the individual effects of each agent. HeLa TI cells are competent to metabolize xenobiotics and possess constitutively expressed and inducible cytochrome P450 mono-oxygenases involved in xenobiotic biotransformation. Thus, HeLa TI cells may be used as an adequate test system for the extensive screening of chemicals, including those that must be metabolically activated. Studying the additional metabolic activation of xenobiotics, we surprisingly found that the rat liver S9 fraction, which has been widely used for xenobiotic activation in genotoxicity tests, reactivated epigenetically silenced genes. Applying the HeLa TI system, we show that N-nitrosodiphenylamine and N-nitrosodimethylamine reactivate epigenetically silenced genes, probably by affecting DNA methylation.
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Affiliation(s)
- Varvara Maksimova
- Department of Chemical Carcinogenesis, Institute of Carcinogenesis, N.N. Blokhin National Medical Research Center of Oncology, Moscow, Russia
- * E-mail:
| | - Natalya Shalginskikh
- Department of Chemical Carcinogenesis, Institute of Carcinogenesis, N.N. Blokhin National Medical Research Center of Oncology, Moscow, Russia
- Fox Chase Cancer Center, Temple University, Philadelphia, PA, United States of America
| | - Olga Vlasova
- Department of Chemical Carcinogenesis, Institute of Carcinogenesis, N.N. Blokhin National Medical Research Center of Oncology, Moscow, Russia
| | - Olga Usalka
- Department of Chemical Carcinogenesis, Institute of Carcinogenesis, N.N. Blokhin National Medical Research Center of Oncology, Moscow, Russia
- International School "Medicine of the Future", Sechenov University, Moscow, Russia
| | - Anastasia Beizer
- Department of Chemical Carcinogenesis, Institute of Carcinogenesis, N.N. Blokhin National Medical Research Center of Oncology, Moscow, Russia
| | - Polina Bugaeva
- Department of Translational Neurobiology, Julius-Maximilians-Universität of Würzburg, Würzburg, Germany
| | - Dmitry Fedorov
- Department of Chemical Carcinogenesis, Institute of Carcinogenesis, N.N. Blokhin National Medical Research Center of Oncology, Moscow, Russia
- Department of Urology, A.V. Vishnevsky National Medical Research Center of Surgery, Moscow, Russia
| | - Olga Lizogub
- Department of Chemical Carcinogenesis, Institute of Carcinogenesis, N.N. Blokhin National Medical Research Center of Oncology, Moscow, Russia
- International School "Medicine of the Future", Sechenov University, Moscow, Russia
| | - Ekaterina Lesovaya
- Department of Chemical Carcinogenesis, Institute of Carcinogenesis, N.N. Blokhin National Medical Research Center of Oncology, Moscow, Russia
- Department of Oncology, Ryazan State Medical University, Ryazan, Russia
| | - Richard Katz
- Fox Chase Cancer Center, Temple University, Philadelphia, PA, United States of America
| | - Gennady Belitsky
- Department of Chemical Carcinogenesis, Institute of Carcinogenesis, N.N. Blokhin National Medical Research Center of Oncology, Moscow, Russia
| | - Kirill Kirsanov
- Department of Chemical Carcinogenesis, Institute of Carcinogenesis, N.N. Blokhin National Medical Research Center of Oncology, Moscow, Russia
- Department of General and Medical Practice, Medical Institute, The Peoples’ Friendship University of Russia, Moscow, Russia
| | - Marianna Yakubovskaya
- Department of Chemical Carcinogenesis, Institute of Carcinogenesis, N.N. Blokhin National Medical Research Center of Oncology, Moscow, Russia
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Padilha EC, Shah P, Rai G, Xu X. NOX2 inhibitor GSK2795039 metabolite identification towards drug optimization. J Pharm Biomed Anal 2021; 201:114102. [PMID: 33992989 DOI: 10.1016/j.jpba.2021.114102] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 04/22/2021] [Accepted: 04/23/2021] [Indexed: 01/21/2023]
Abstract
Overproduction of reactive oxygen species (ROS) can lead to several disease states, such as diabetic nephropathy and amyotrophic lateral sclerosis. One of the most studied mechanisms to inhibit the over production of ROS is the inhibition of NADPH oxidase (NOX) enzymes, which catalyze the conversion of cytoplasmic NADPH to NADP+, resulting in the formation of superoxide anions. GSK2795039 has been shown to selectively inhibit the NOX2 isoform, however, clearance of the compound was high in rats and mice. Therefore, identifying metabolic soft spots would be crucial in guiding the optimization process to improve its pharmacokinetic properties. GSK2795039 (10 μM) was incubated in the presence of mouse, rat and human liver microsomal (1 mg/mL) and cytosolic (2 mg/mL) fractions and appropriate co-factors, followed by MSe fragment analysis to identify metabolic soft spots. GSK2795039 showed marked species differences in its metabolism. The alkyl side chains and indoline moiety were the most common sites of biotransformation. The compound was identified to be an aldehyde oxidase substrate. Additionally, unique human metabolites were observed in vitro. Our study sheds light on structure optimization opportunities for developing improved NOX2 inhibitors, and it will help overcome the challenges involved in preclinical species selection for its safety evaluations.
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Affiliation(s)
- Elias Carvalho Padilha
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, United States
| | - Pranav Shah
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, United States
| | - Ganesha Rai
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, United States
| | - Xin Xu
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, United States.
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18
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Shao Y, Schiwy A, Glauch L, Henneberger L, König M, Mühlenbrink M, Xiao H, Thalmann B, Schlichting R, Hollert H, Escher BI. Optimization of a pre-metabolization procedure using rat liver S9 and cell-extracted S9 in the Ames fluctuation test. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 749:141468. [PMID: 32827816 DOI: 10.1016/j.scitotenv.2020.141468] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 08/01/2020] [Accepted: 08/02/2020] [Indexed: 06/11/2023]
Abstract
Many environmental pollutants pose a toxicological hazard only after metabolic activation. In vitro bioassays using cell lines or bacteria have often no or reduced metabolic activity, which impedes their use in the risk assessment. To improve the predictive capability of in vitro assays, external metabolization systems like the liver S9 fraction are frequently combined with in vitro toxicity assays. While it is typical for S9 fractions that samples and testing systems are combined in the same exposure system, we propose to separate the metabolism step and toxicity measurement. This allows for a modular combination of metabolic activation by enzymes isolated from rat liver (S9) or a biotechnological alternative (ewoS9R) with in vitro bioassays that lack metabolic capacity. Benzo(a)pyrene and 2-aminoanthracene were used as model compounds to optimize the conditions for the S9 metabolic degradation/activation step. The Ames assay with Salmonella typhimurium strains TA98 and TA100 was applied to validate the set-up of decoupling the S9 activation/metabolism from the bioassay system. S9 protein concentration of 0.25 mgprotein/mL, a supplement of 0.13 mM NADPH and a pre-incubation time of 100 min are recommended for activation of samples prior to dosing them to in vitro bioassays using the regular dosing protocols of the respective bioassay. EwoS9R performed equally well as Moltox S9, which is a step forward in developing true animal-free in vitro bioassays. After pre-incubation with S9 fraction, chemicals induced bacteria revertants in both the TA98 and the TA100 assay as efficiently as the standard Ames assay. The pre-incubation of chemicals with S9 fraction could serve for a wide range of cellular in vitro assays to efficiently combine activation and toxicity measurement, which may greatly facilitate the application of these assays for chemical hazard assessment and monitoring of environmental samples.
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Affiliation(s)
- Ying Shao
- UFZ - Helmholtz Centre for Environmental Research, Department of Cell Toxicology, Permoser Str. 15, 04318 Leipzig, Germany; Key Laboratory of the Three Gorges Reservoir Eco-environment, Ministry of Education, Chongqing University, Shazheng street 174, Shapingba, 400044 Chongqing, China.
| | - Andreas Schiwy
- Department of Ecosystem Analysis, Institute for Environmental Research, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany; EWOMIS GmbH, Schießstraße 26c, 63486 Bruchköbel, Germany; Department of Evolutionary Ecology and Ecotoxicology, Goethe University, Max-von-Laue-Str. 13, 60438 Frankfurt/Main, Germany
| | - Lisa Glauch
- UFZ - Helmholtz Centre for Environmental Research, Department of Cell Toxicology, Permoser Str. 15, 04318 Leipzig, Germany
| | - Luise Henneberger
- UFZ - Helmholtz Centre for Environmental Research, Department of Cell Toxicology, Permoser Str. 15, 04318 Leipzig, Germany
| | - Maria König
- UFZ - Helmholtz Centre for Environmental Research, Department of Cell Toxicology, Permoser Str. 15, 04318 Leipzig, Germany
| | - Marie Mühlenbrink
- UFZ - Helmholtz Centre for Environmental Research, Department of Cell Toxicology, Permoser Str. 15, 04318 Leipzig, Germany
| | - Hongxia Xiao
- Department of Ecosystem Analysis, Institute for Environmental Research, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany; EWOMIS GmbH, Schießstraße 26c, 63486 Bruchköbel, Germany
| | - Beat Thalmann
- EWOMIS GmbH, Schießstraße 26c, 63486 Bruchköbel, Germany
| | - Rita Schlichting
- UFZ - Helmholtz Centre for Environmental Research, Department of Cell Toxicology, Permoser Str. 15, 04318 Leipzig, Germany
| | - Henner Hollert
- Department of Ecosystem Analysis, Institute for Environmental Research, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany; EWOMIS GmbH, Schießstraße 26c, 63486 Bruchköbel, Germany; Department of Evolutionary Ecology and Ecotoxicology, Goethe University, Max-von-Laue-Str. 13, 60438 Frankfurt/Main, Germany
| | - Beate I Escher
- UFZ - Helmholtz Centre for Environmental Research, Department of Cell Toxicology, Permoser Str. 15, 04318 Leipzig, Germany; EWOMIS GmbH, Schießstraße 26c, 63486 Bruchköbel, Germany; Eberhard Karls University of Tübingen, Environmental Toxicology, Centre for Applied Geosciences, 72074 Tubingen, Germany
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Ooka M, Lynch C, Xia M. Application of In Vitro Metabolism Activation in High-Throughput Screening. Int J Mol Sci 2020; 21:ijms21218182. [PMID: 33142951 PMCID: PMC7663506 DOI: 10.3390/ijms21218182] [Citation(s) in RCA: 163] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/25/2020] [Accepted: 10/26/2020] [Indexed: 02/06/2023] Open
Abstract
In vitro methods which incorporate metabolic capability into the assays allow us to assess the activity of metabolites from their parent compounds. These methods can be applied into high-throughput screening (HTS) platforms, thereby increasing the speed to identify compounds that become active via the metabolism process. HTS was originally used in the pharmaceutical industry and now is also used in academic settings to evaluate biological activity and/or toxicity of chemicals. Although most chemicals are metabolized in our body, many HTS assays lack the capability to determine compound activity via metabolism. To overcome this problem, several in vitro metabolic methods have been applied to an HTS format. In this review, we describe in vitro metabolism methods and their application in HTS assays, as well as discuss the future perspectives of HTS with metabolic activity. Each in vitro metabolism method has advantages and disadvantages. For instance, the S9 mix has a full set of liver metabolic enzymes, but it displays high cytotoxicity in cell-based assays. In vitro metabolism requires liver fractions or the use of other metabolically capable systems, including primary hepatocytes or recombinant enzymes. Several newly developed in vitro metabolic methods, including HepaRG cells, three-dimensional (3D) cell models, and organ-on-a-chip technology, will also be discussed. These newly developed in vitro metabolism approaches offer significant progress in dissecting biological processes, developing drugs, and making toxicology studies quicker and more efficient.
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Lee YK, Thong OM, Sunderasan E, Norazreen AR, Sreeramanan S. Cytotoxicity and genotoxicity of Hevea brasiliensis latex C-serum DCS sub-fraction as anticancer agents. J RUBBER RES 2020. [DOI: 10.1007/s42464-020-00056-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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21
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Gooderham NJ, Cohen SM, Eisenbrand G, Fukushima S, Guengerich FP, Hecht SS, Rietjens IMCM, Rosol TJ, Bastaki M, Linman MJ, Taylor SV. The safety evaluation of food flavoring substances: the role of genotoxicity studies. Crit Rev Toxicol 2020; 50:1-27. [PMID: 32162576 DOI: 10.1080/10408444.2020.1712589] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The Flavor and Extract Manufacturers Association (FEMA) Expert Panel relies on the weight of evidence from all available data in the safety evaluation of flavoring substances. This process includes data from genotoxicity studies designed to assess the potential of a chemical agent to react with DNA or otherwise cause changes to DNA, either in vitro or in vivo. The Panel has reviewed a large number of in vitro and in vivo genotoxicity studies during the course of its ongoing safety evaluations of flavorings. The adherence of genotoxicity studies to standardized protocols and guidelines, the biological relevance of the results from those studies, and the human relevance of these studies are all important considerations in assessing whether the results raise specific concerns for genotoxic potential. The Panel evaluates genotoxicity studies not only for evidence of genotoxicity hazard, but also for the probability of risk to the consumer in the context of exposure from their use as flavoring substances. The majority of flavoring substances have given no indication of genotoxic potential in studies evaluated by the FEMA Expert Panel. Examples illustrating the assessment of genotoxicity data for flavoring substances and the consideration of the factors noted above are provided. The weight of evidence approach adopted by the FEMA Expert Panel leads to a rational assessment of risk associated with consumer intake of flavoring substances under the conditions of use.
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Affiliation(s)
| | - Samuel M Cohen
- Havlik-Wall Professor of Oncology, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Gerhard Eisenbrand
- Food Chemistry & Toxicology, University of Kaiserslautern (retired), Heidelberg, Germany
| | | | - F Peter Guengerich
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Stephen S Hecht
- Masonic Cancer Center and Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, USA
| | | | - Thomas J Rosol
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, USA
| | - Maria Bastaki
- Flavor and Extract Manufacturers Association, Washington, DC, USA
| | - Matthew J Linman
- Flavor and Extract Manufacturers Association, Washington, DC, USA
| | - Sean V Taylor
- Flavor and Extract Manufacturers Association, Washington, DC, USA
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22
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Buick JK, Williams A, Gagné R, Swartz CD, Recio L, Ferguson SS, Yauk CL. Flow cytometric micronucleus assay and TGx-DDI transcriptomic biomarker analysis of ten genotoxic and non-genotoxic chemicals in human HepaRG™ cells. Genes Environ 2020; 42:5. [PMID: 32042365 PMCID: PMC7001283 DOI: 10.1186/s41021-019-0139-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 11/27/2019] [Indexed: 11/10/2022] Open
Abstract
Background Modern testing paradigms seek to apply human-relevant cell culture models and integrate data from multiple test systems to accurately inform potential hazards and modes of action for chemical toxicology. In genetic toxicology, the use of metabolically competent human hepatocyte cell culture models provides clear advantages over other more commonly used cell lines that require the use of external metabolic activation systems, such as rat liver S9. HepaRG™ cells are metabolically competent cells that express Phase I and II metabolic enzymes and differentiate into mature hepatocyte-like cells, making them ideal for toxicity testing. We assessed the performance of the flow cytometry in vitro micronucleus (MN) test and the TGx-DDI transcriptomic biomarker to detect DNA damage-inducing (DDI) chemicals in human HepaRG™ cells after a 3-day repeat exposure. The biomarker, developed for use in human TK6 cells, is a panel of 64 genes that accurately classifies chemicals as DDI or non-DDI. Herein, the TGx-DDI biomarker was analyzed by Ion AmpliSeq whole transcriptome sequencing to assess its classification accuracy using this more modern gene expression technology as a secondary objective. Methods HepaRG™ cells were exposed to increasing concentrations of 10 test chemicals (six genotoxic chemicals, including one aneugen, and four non-genotoxic chemicals). Cytotoxicity and genotoxicity were measured using the In Vitro MicroFlow® kit, which was run in parallel with the TGx-DDI biomarker. Results A concentration-related decrease in relative survival and a concomitant increase in MN frequency were observed for genotoxic chemicals in HepaRG™ cells. All five DDI and five non-DDI agents were correctly classified (as genotoxic/non-genotoxic and DDI/non-DDI) by pairing the test methods. The aneugenic agent (colchicine) yielded the expected positive result in the MN test and negative (non-DDI) result by TGx-DDI. Conclusions This next generation genotoxicity testing strategy is aligned with the paradigm shift occurring in the field of genetic toxicology. It provides mechanistic insight in a human-relevant cell-model, paired with measurement of a conventional endpoint, to inform the potential for adverse health effects. This work provides support for combining these assays in an integrated test strategy for accurate, higher throughput genetic toxicology testing in this metabolically competent human progenitor cell line.
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Affiliation(s)
- Julie K Buick
- 1Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario K1A 0K9 Canada
| | - Andrew Williams
- 1Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario K1A 0K9 Canada
| | - Rémi Gagné
- 1Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario K1A 0K9 Canada
| | - Carol D Swartz
- 2Integrated Laboratory Systems Inc. (ILS), Research Triangle Park, Durham, North Carolina 27709 USA
| | - Leslie Recio
- 2Integrated Laboratory Systems Inc. (ILS), Research Triangle Park, Durham, North Carolina 27709 USA
| | - Stephen S Ferguson
- 3National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, Durham, North Carolina 27709 USA
| | - Carole L Yauk
- 1Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario K1A 0K9 Canada.,4Health Canada, Environmental Health Centre, 50 Colombine Driveway, PL 0803A, Ottawa, Ontario K1A 0K9 Canada
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Kreuzer K, Frenzel F, Lampen A, Braeuning A, Böhmert L. Transcriptomic effect marker patterns of genotoxins - a comparative study with literature data. J Appl Toxicol 2019; 40:448-457. [PMID: 31845381 DOI: 10.1002/jat.3928] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 10/29/2019] [Accepted: 11/03/2019] [Indexed: 01/19/2023]
Abstract
Microarray approaches are frequently used experimental tools which have proven their value for example in the characterization of the molecular mode of action of toxicologically relevant compounds. In a regulatory context, omics techniques are still not routinely used, amongst others due to lacking standardization in experimental setup and data processing, and also due to issues with the definition of adversity. In order to exemplarily determine whether consensus transcript biomarker signatures for a certain toxicological endpoint can be derived from published microarray datasets, we here compared transcriptome data from human HepaRG hepatocarcinoma cells treated with different genotoxins, based on re-analyzed datasets extracted from the literature. Comparison of the resulting data show that even with similarly-acting compounds in the same cell line, considerable variation was observed with respect to the numbers and identities of differentially expressed genes. Greater concordance was observed when considering the whole data sets and biological functions associated with the genes affected. The present results highlight difficulties and possibilities in inter-experiment comparisons of omics data and underpin the need for future efforts towards improved standardization to facilitate the use of omics data in risk assessment. Existing omics datasets may nonetheless prove valuable in establishing biological context information essential for the development of adverse outcome pathways.
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Affiliation(s)
- Katrin Kreuzer
- Dept. Food Safety, German Federal Institute for Risk Assessment, Berlin, Germany
| | - Falko Frenzel
- Dept. Food Safety, German Federal Institute for Risk Assessment, Berlin, Germany
| | - Alfonso Lampen
- Dept. Food Safety, German Federal Institute for Risk Assessment, Berlin, Germany
| | - Albert Braeuning
- Dept. Food Safety, German Federal Institute for Risk Assessment, Berlin, Germany
| | - Linda Böhmert
- Dept. Food Safety, German Federal Institute for Risk Assessment, Berlin, Germany
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Demonstrating laboratory proficiency in bacterial mutagenicity assays for regulatory submission. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2019; 848:403075. [DOI: 10.1016/j.mrgentox.2019.07.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 05/30/2019] [Accepted: 07/11/2019] [Indexed: 11/18/2022]
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Mišík M, Nersesyan A, Ropek N, Huber WW, Haslinger E, Knasmueller S. Use of human derived liver cells for the detection of genotoxins in comet assays. MUTATION RESEARCH/GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2019; 845:402995. [DOI: 10.1016/j.mrgentox.2018.12.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 12/03/2018] [Accepted: 12/09/2018] [Indexed: 04/09/2023]
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26
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Ebmeyer J, Braeuning A, Glatt H, These A, Hessel-Pras S, Lampen A. Human CYP3A4-mediated toxification of the pyrrolizidine alkaloid lasiocarpine. Food Chem Toxicol 2019; 130:79-88. [PMID: 31103741 DOI: 10.1016/j.fct.2019.05.019] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 05/08/2019] [Accepted: 05/13/2019] [Indexed: 01/05/2023]
Abstract
Pyrrolizidine alkaloids (PA) are widely distributed phytotoxins contaminating food and feed. Hepatic enzymes are considered to bioactivate PA. Previous studies showed differences in the metabolism rate in liver homogenates of different species. Thus, uncertainty remains with respect to the relevance of human metabolism. Our study aimed to analyze whether the PA representative lasiocarpine is toxified by human cytochrome P450 (CYP) enzymes. We compared the metabolic elimination of lasiocarpine in the presence of rat and human S9 fractions and liver microsomes. Experiments with the potent CYP3A/Cyp3a inhibitor ketoconazole and supersomes containing individual human and rat CYPs revealed that enzymes of the CYP3A/Cyp3a family of both species are of major relevance for lasiocarpine metabolism. To assess if metabolism by human CYP3A4 results in a toxification of lasiocarpine we performed experiments with V79 cells. γH2AX and micronucleus formation were analyzed as endpoints for genotoxicity. No effects were observed in the wildtype cells, which lack CYP activity. By contrast, a V79 clone engineered for expression of human CYP3A4 showed concentration-dependent γH2AX and micronucleus formation. Concluding, our results showed the CYP3A4-dependent formation of genotoxic metabolites of lasiocarpine. The results confirm previous data indicating the need to include metabolism of PA for human risk assessment.
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Affiliation(s)
- Johanna Ebmeyer
- German Federal Institute for Risk Assessment, Department Food Safety, Max-Dohrn-Straße 8-10, 10589, Berlin, Germany
| | - Albert Braeuning
- German Federal Institute for Risk Assessment, Department Food Safety, Max-Dohrn-Straße 8-10, 10589, Berlin, Germany
| | - Hansruedi Glatt
- German Federal Institute for Risk Assessment, Department Food Safety, Max-Dohrn-Straße 8-10, 10589, Berlin, Germany
| | - Anja These
- German Federal Institute for Risk Assessment, Department Safety in the Food Chain, Max-Dohrn-Straße 8-10, 10589, Berlin, Germany
| | - Stefanie Hessel-Pras
- German Federal Institute for Risk Assessment, Department Food Safety, Max-Dohrn-Straße 8-10, 10589, Berlin, Germany.
| | - Alfonso Lampen
- German Federal Institute for Risk Assessment, Department Food Safety, Max-Dohrn-Straße 8-10, 10589, Berlin, Germany
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Cox JA, Zwart EP, Luijten M, White PA. The development and prevalidation of an in vitro mutagenicity assay based on MutaMouse primary hepatocytes, Part I: Isolation, structural, genetic, and biochemical characterization. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2019; 60:331-347. [PMID: 30592088 PMCID: PMC6590113 DOI: 10.1002/em.22253] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 09/10/2018] [Accepted: 09/15/2018] [Indexed: 06/09/2023]
Abstract
To develop an improved in vitro mammalian cell gene mutation assay, it is imperative to address the known deficiencies associated with existing assays. Primary hepatocytes isolated from the MutaMouse are ideal for an in vitro gene mutation assay due to their metabolic competence, their "normal" karyotype (i.e., neither transformed nor immortalized), and the presence of the MutaMouse transgene for rapid and reliable mutation scoring. The cells were extensively characterized to confirm their utility. Freshly isolated cells were found to have a hepatocyte-like morphology, predominantly consisting of binucleated cells. These cells maintain hepatocyte-specific markers for up to 3 days in culture. Analyses revealed a normal murine hepatocyte karyotype with a modal ploidy number of 4n. Fluorescence in situ hybridization analysis confirmed the presence of the lambda shuttle vector on chromosome 3. The doubling time was determined to be 22.5 ± 3.3 h. Gene expression and enzymatic activity of key Phase I and Phase II metabolic enzymes were maintained for at least 8 and 24 h in culture, respectively. Exposure to β-naphthoflavone led to approximately 900- and 9-fold increases in Cyp1a1 and Cyp1a2 gene expression, respectively, and approximately twofold induction in cytochrome P450 (CYP) 1A1/1A2 activity. Exposure to phenobarbital resulted in an approximately twofold increase in CYP 2B6 enzyme activity. Following this characterization, it is evident that MutaMouse primary hepatocytes have considerable promise for in vitro mutagenicity assessment. The performance of these cells in an in vitro gene mutation assay is assessed in Part II. Environ. Mol. Mutagen. 60:331-347, 2019. © 2018 The Authors. Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society.
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Affiliation(s)
- Julie A. Cox
- Environmental Health Science and Research Bureau, Health CanadaOttawaOntarioCanada
- Department of BiologyUniversity of OttawaOntarioCanada
| | - Edwin P. Zwart
- Centre for Health ProtectionNational Institute for Public Health and the Environment (RIVM)BilthovenThe Netherlands
| | - Mirjam Luijten
- Centre for Health ProtectionNational Institute for Public Health and the Environment (RIVM)BilthovenThe Netherlands
| | - Paul A. White
- Environmental Health Science and Research Bureau, Health CanadaOttawaOntarioCanada
- Department of BiologyUniversity of OttawaOntarioCanada
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May JE, Donaldson C, Gynn L, Morse HR. Chemotherapy-induced genotoxic damage to bone marrow cells: long-term implications. Mutagenesis 2019; 33:241-251. [PMID: 30239865 DOI: 10.1093/mutage/gey014] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 07/11/2018] [Indexed: 12/26/2022] Open
Abstract
Mesenchymal stem/stromal cells (MSCs) within the bone marrow (BM) are vitally important in forming the micro-environment supporting haematopoiesis after myeloablative chemotherapy. MSCs are known to be damaged phenotypically and functionally by chemotherapy; however, to the best our knowledge, the persistence of genotoxic effects of chemotherapy on the BM micro-environment has not been studied. We therefore aimed to evaluate genotoxic effects of chemotherapy on the BM both in vitro and in vivo, using the comet and micronucleus assays, focussing on the persistence of DNA lesions that may contribute to complications in the patient. The MSC cell line (HS-5) and primary cord blood mononuclear cells (CBMNCs: a source of undamaged DNA) were exposed to the chemotherapeutic agent cyclophosphamide (CY) within a physiologically relevant in vitro model. CY treatment resulted in significant increases in CBMNC DNA damage at all time points tested (3-48 h exposure). Similarly, HS-5 cells exposed to CY exhibited significant increases in DNA damage as measured by the comet assay, with increased numbers of abnormal cells visible in the micronucleus assay. In addition, even 48 h after removal of 48-h CY treatment, DNA damage remains significantly increased in treated cells relative to controls. In patients treated with chemotherapy for haematological malignancy, highly significant increases in damaged DNA were seen in BM cells isolated from one individual 1 year after completion of therapy for acute leukaemia compared with pretreatment (P < 0.001). Similarly, two individuals treated 7 and 17 years previously with chemotherapy exhibited significant increases of damaged DNA in MSC compared with untreated age- and sex-matched controls (P < 0.05). Unlike haematopoietic cells, MSCs are not replaced following a stem cell transplant. Therefore, long-term damage to MSC may impact on engraftment of either allogeneic or autologous transplants. In addition, persistence of DNA lesions may lead to genetic instability, correlating with the significant number of chemotherapy-treated individuals who have therapy-related malignancies.
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Affiliation(s)
- Jennifer E May
- Centre for Research in Biosciences, University of the West of England, Coldharbour Lane, Bristol, UK
| | - Craig Donaldson
- School of Biomedical Sciences, University of Plymouth, Plymouth, Devon, UK
| | - Liana Gynn
- Centre for Research in Biosciences, University of the West of England, Coldharbour Lane, Bristol, UK
| | - H Ruth Morse
- Centre for Research in Biosciences, University of the West of England, Coldharbour Lane, Bristol, UK
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Kishino Y, Hasegawa T, Kato A, Nishiya Y, Rozhnal V, Watanabe K, Takasaki W, Yamoto T, Mori K. Effect of inter-individual variability in human liver cytochrome P450 isozymes on cyclophosphamide-induced micronucleus formation. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2018; 838:37-45. [PMID: 30678826 DOI: 10.1016/j.mrgentox.2018.11.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 11/30/2018] [Accepted: 11/30/2018] [Indexed: 10/27/2022]
Abstract
We investigated the relationship between metabolic activities of cytochrome P450 (CYP) isozymes present in microsomal fractions derived from the livers of 78 donors and micronucleus induction by cyclophosphamide (CPA). Consequently, a wide inter-individual variation in CYP activities was observed among the 78 donors. The CYP activities were partially correlated with the metabolic phenotypes predicted for the donors based on their single nucleotide polymorphisms. In addition, CPA induced micronucleus formation was seen for 47 out of 52 donors whose samples were tested with CPA doses ranging from 18.8 to 100 μg/mL. The CPA dose at which micronucleated cells were observed varied among the donors. Furthermore, a close correlation was identified between the catalytic activities of the CYP2B6, CYP2C9, CYP2C19, and CYP3A4 isozymes and micronucleus induction by CPA. To elucidate the mechanism underlying CPA-induced micronucleus formation in vitro tests were conducted on expression systems of CYP2B6, CYP2C9, CYP2C19, CYP2D6, and CYP3A4. Additionally, the metabolites of CPA generated by the expression systems were quantified by a liquid chromatography tandem mass spectrometer. Interestingly, several metabolites including the 4-hydroxyl form of CPA (4-OH-CPA) and phosphamide mustard were detected in the CYP2B6, CYP2C19, and CYP3A4 expression systems, but not in the CYP2C9 and CYP2D6 system. The presence of these metabolites was correlated with micronucleus induction by CPA. The absence of CPA metabolites in the CYP2C9 expression system might be associated with the lower 4-hydroxylase activity of this system. The present results suggest that inter-individual variability in the metabolic capacity of each donor was associated with potential micronucleus induction due to CPA. Additionally, CPA metabolites like 4-OH-CPA and phosphamide mustard produced by human CYP2B6, CYP2C9, CYP2C19, and CYP3A4 are suggested to be major determinants of micronucleus induction by CPA.
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Affiliation(s)
- Yuki Kishino
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co., Ltd., 1-16-13 Kitakasai, Edogawa-ku, Tokyo, 134-8630, Japan.
| | - Tomoko Hasegawa
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co., Ltd., 1-16-13 Kitakasai, Edogawa-ku, Tokyo, 134-8630, Japan
| | - Ayako Kato
- Translational Research Department, Daiichi Sankyo RD Novare Co., Ltd., 1-16-13 Kitakasai, Edogawa-ku, Tokyo, 134-8630, Japan
| | - Yumi Nishiya
- Drug Metabolism and Pharmacokinetics Research Laboratories, Daiichi Sankyo Co., Ltd., 1-2-58 Hiromachi, Shinagawa-ku, Tokyo, 140-8710, Japan
| | - Veronika Rozhnal
- Tissue and Cell Research Center Munich, Daiichi Sankyo Europe, GmbH, Bunsenstrasse 7, 82152, Martinsried, Germany
| | - Kyoko Watanabe
- Drug Metabolism and Pharmacokinetics Research Laboratories, Daiichi Sankyo Co., Ltd., 1-2-58 Hiromachi, Shinagawa-ku, Tokyo, 140-8710, Japan
| | - Wataru Takasaki
- Research and Development Planning and Management Department, Daiichi Sankyo Co., Ltd., 1-2-58 Hiromachi, Shinagawa-ku, Tokyo, 140-8710, Japan
| | - Takashi Yamoto
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co., Ltd., 1-16-13 Kitakasai, Edogawa-ku, Tokyo, 134-8630, Japan
| | - Kazuhiko Mori
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co., Ltd., 1-16-13 Kitakasai, Edogawa-ku, Tokyo, 134-8630, Japan
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Santes-Palacios R, Camacho-Carranza R, Espinosa-Aguirre JJ. Bacterial mutagenicity of selected procarcinogens in the presence of recombinant human or rat cytochrome P4501A1. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2018; 835:25-31. [DOI: 10.1016/j.mrgentox.2018.09.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Revised: 09/05/2018] [Accepted: 09/06/2018] [Indexed: 12/30/2022]
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Godinho ALA, Martins IL, Nunes J, Charneira C, Grilo J, Silva DM, Pereira SA, Soto K, Oliveira MC, Marques MM, Jacob CC, Antunes AMM. High resolution mass spectrometry-based methodologies for identification of Etravirine bioactivation to reactive metabolites: In vitro and in vivo approaches. Eur J Pharm Sci 2018; 119:70-82. [PMID: 29592839 DOI: 10.1016/j.ejps.2018.03.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 02/28/2018] [Accepted: 03/22/2018] [Indexed: 01/16/2023]
Abstract
Drug bioactivation to reactive metabolites capable of covalent adduct formation with bionucleophiles is a major cause of drug-induced adverse reactions. Therefore, elucidation of reactive metabolites is essential to unravel the toxicity mechanisms induced by drugs and thereby identify patient subgroups at higher risk. Etravirine (ETR) was the first second-generation Non-Nucleoside Reverse Transcriptase Inhibitor (NNRTI) to be approved, as a therapeutic option for HIV-infected patients who developed resistance to the first-generation NNRTIs. Additionally, ETR came into market aiming to overcome some adverse effects associated with the previously used efavirenz (neurotoxicity) and nevirapine (hepatotoxicity) therapies. Nonetheless, post-marketing reports of severe ETR-induced skin rash and hypersensitivity reactions have prompted the U.S. FDA to issue a safety alert on ETR. Taking into consideration that ETR usage may increase in the near future, due to the possible use of the drug for coinfection with malaria and HIV, the development of reliable prognostic tools for early risk/benefit estimations is urgent. In the current study, high resolution mass spectrometry-based methodologies were integrated with MS3 experiments for the identification of reactive ETR metabolites/adducts: 1) in vitro incubation of the drug with human and rat liver S9 fractions in the presence of Phase I and II co-factors, including glutathione, as a trapping bionucleophile; and 2) in vivo, using urine samples from HIV-infected patients on ETR therapy. We obtained evidence for multiple bioactivation pathways leading to the formation of covalent adducts with glutathione and N-acetyl-L-cysteine. These results suggest that similar reactions may occur with cysteine residues of proteins, supporting a role for ETR bioactivation in the onset of the toxic effects elicited by the drug. Additionally, ETR metabolites stemming from amine oxidation, with potential toxicological significance, were identified in vitro and in vivo. Also noteworthy is the fact that new metabolic conjugation pathways of glucuronide metabolites were demonstrated for the first time, raising questions about their potential toxicological implications. In conclusion, these results represent not only a contribution towards the elucidation of new metabolic pathways of drugs in general but also an important step towards the elucidation of potentially toxic ETR pathways, whose understanding may be crucial for reliable risk/benefit estimations of ETR-based regimens.
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Affiliation(s)
- Ana L A Godinho
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - Inês L Martins
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - João Nunes
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - Catarina Charneira
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - Jorge Grilo
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal
| | - Diogo M Silva
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - Sofia A Pereira
- CEDOC, Chronic Diseases Research Centre, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, 1169-006 Lisboa, Portugal
| | - Karina Soto
- Hospital Prof. Doutor Fernando Fonseca E.P.E., IC 19, 2720-276 Amadora, Portugal
| | - M Conceição Oliveira
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - M Matilde Marques
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - Cristina C Jacob
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal.
| | - Alexandra M M Antunes
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal.
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Besaratinia A, Zheng A, Bates SE, Tommasi S. Mutation Analysis in Cultured Cells of Transgenic Rodents. Int J Mol Sci 2018; 19:E262. [PMID: 29337872 PMCID: PMC5796208 DOI: 10.3390/ijms19010262] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 01/10/2018] [Accepted: 01/15/2018] [Indexed: 01/08/2023] Open
Abstract
To comply with guiding principles for the ethical use of animals for experimental research, the field of mutation research has witnessed a shift of interest from large-scale in vivo animal experiments to small-sized in vitro studies. Mutation assays in cultured cells of transgenic rodents constitute, in many ways, viable alternatives to in vivo mutagenicity experiments in the corresponding animals. A variety of transgenic rodent cell culture models and mutation detection systems have been developed for mutagenicity testing of carcinogens. Of these, transgenic Big Blue® (Stratagene Corp., La Jolla, CA, USA, acquired by Agilent Technologies Inc., Santa Clara, CA, USA, BioReliance/Sigma-Aldrich Corp., Darmstadt, Germany) mouse embryonic fibroblasts and the λ Select cII Mutation Detection System have been used by many research groups to investigate the mutagenic effects of a wide range of chemical and/or physical carcinogens. Here, we review techniques and principles involved in preparation and culturing of Big Blue® mouse embryonic fibroblasts, treatment in vitro with chemical/physical agent(s) of interest, determination of the cII mutant frequency by the λ Select cII assay and establishment of the mutation spectrum by DNA sequencing. We describe various approaches for data analysis and interpretation of the results. Furthermore, we highlight representative studies in which the Big Blue® mouse cell culture model and the λ Select cII assay have been used for mutagenicity testing of diverse carcinogens. We delineate the advantages of this approach and discuss its limitations, while underscoring auxiliary methods, where applicable.
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Affiliation(s)
- Ahmad Besaratinia
- Department of Preventive Medicine, University of Southern California Keck School of Medicine, University of Southern California, M/C 9603, Los Angeles, CA 90033, USA.
| | - Albert Zheng
- Department of Preventive Medicine, University of Southern California Keck School of Medicine, University of Southern California, M/C 9603, Los Angeles, CA 90033, USA.
| | - Steven E Bates
- Department of Cancer Biology, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA.
| | - Stella Tommasi
- Department of Preventive Medicine, University of Southern California Keck School of Medicine, University of Southern California, M/C 9603, Los Angeles, CA 90033, USA.
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Nesslany F. The current limitations of in vitro genotoxicity testing and their relevance to the in vivo situation. Food Chem Toxicol 2017; 106:609-615. [DOI: 10.1016/j.fct.2016.08.035] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 08/12/2016] [Accepted: 08/30/2016] [Indexed: 11/29/2022]
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Galloway SM. International regulatory requirements for genotoxicity testing for pharmaceuticals used in human medicine, and their impurities and metabolites. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2017; 58:296-324. [PMID: 28299826 DOI: 10.1002/em.22077] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 02/05/2017] [Indexed: 06/06/2023]
Abstract
The process of developing international (ICH) guidelines is described, and the main guidelines reviewed are the ICH S2(R1) guideline that includes the genotoxicity test battery for human pharmaceuticals, and the ICH M7 guideline for assessing and limiting potentially mutagenic impurities and degradation products in drugs. Key aspects of the guidelines are reviewed in the context of drug development, for example the incorporation of genotoxicity assessment into non-clinical toxicity studies, and ways to develop and assess weight of evidence. In both guidelines, the existence of "thresholds" or non-linear dose responses for genotoxicity plays a part in the strategies. Differences in ICH S2(R1) protocol recommendations from OECD guidelines are highlighted and rationales explained. The use of genotoxicity data during clinical development and in assessment of carcinogenic potential is also described. There are no international guidelines on assessment of potentially genotoxic metabolites, but some approaches to safety assessment are discussed for these. Environ. Mol. Mutagen. 58:296-324, 2017. © 2017 Wiley Periodicals, Inc.
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