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Zhang W, Miller CA, Wilson MJ. Assessment of the In Vitro Phosphatidylinositol Glycan Class A (PIG-A) Gene Mutation Assay Using Human TK6 and Mouse Hepa1c1c7 Cell Lines. J Xenobiot 2024; 14:1293-1311. [PMID: 39311152 PMCID: PMC11417843 DOI: 10.3390/jox14030073] [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: 07/31/2024] [Revised: 09/08/2024] [Accepted: 09/13/2024] [Indexed: 09/26/2024] Open
Abstract
Gene mutations linked to diseases like cancer may be caused by exposure to environmental chemicals. The X-linked phosphatidylinositol glycan class A (PIG-A) gene, required for glycosylphosphatidylinositol (GPI) anchor biosynthesis, is a key target locus for in vitro genetic toxicity assays. Various organisms and cell lines may respond differently to genotoxic agents. Here, we compared the mutagenic potential of directly genotoxic ethyl methane sulfonate (EMS) to metabolically activated pro-mutagenic polycyclic aromatic hydrocarbons (PAHs). The two classes of mutagens were compared in an in vitro PIG-A gene mutation test using the metabolically active murine hepatoma Hepa1c1c7 cell line and the human TK6 cell line, which has limited metabolic capability. Determination of cell viability is required for quantifying mutagenicity. Two common cell viability tests, the MTT assay and propidium iodide (PI) staining measured by flow cytometry, were evaluated. The MTT assay overestimated cell viability in adherent cells at high benzo[a]pyrene (B[a]P) exposure concentrations, so PI-based cytotoxicity was used in calculations. The spontaneous mutation rates for TK6 and Hepa1c1c7 cells were 1.87 and 1.57 per million cells per cell cycle, respectively. TK6 cells exposed to 600 µM and 800 µM EMS showed significantly higher mutation frequencies (36 and 47 per million cells per cell cycle, respectively). Exposure to the pro-mutagen benzo[a]pyrene (B[a]P, 10 µM) did not increase mutation frequency in TK6 cells. In Hepa1c1c7 cells, mutation frequencies varied across exposure groups (50, 50, 29, and 81 per million cells per cell cycle when exposed to 10 µM B[a]P, 5-methylcholanthrene (5-MC), chrysene, or 16,000 µM EMS, respectively). We demonstrate that the choice of cytotoxicity assay and cell line can determine the outcome of the Pig-A mutagenesis assay when assessing a specific mutagen.
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Affiliation(s)
- Wenhao Zhang
- Department of Environmental Health Sciences, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA 70112, USA; (C.A.M.); (M.J.W.)
| | - Charles A. Miller
- Department of Environmental Health Sciences, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA 70112, USA; (C.A.M.); (M.J.W.)
| | - Mark J. Wilson
- Department of Environmental Health Sciences, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA 70112, USA; (C.A.M.); (M.J.W.)
- Chemical Insights Research Institute of Underwriters Laboratories Research Institutes, Marietta, GA 30067, USA
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2
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Beal MA, Chen G, Dearfield KL, Gi M, Gollapudi B, Heflich RH, Horibata K, Long AS, Lovell DP, Parsons BL, Pfuhler S, Wills J, Zeller A, Johnson G, White PA. Interpretation of in vitro concentration-response data for risk assessment and regulatory decision-making: Report from the 2022 IWGT quantitative analysis expert working group meeting. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2023. [PMID: 38115239 DOI: 10.1002/em.22582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 09/15/2023] [Accepted: 12/16/2023] [Indexed: 12/21/2023]
Abstract
Quantitative risk assessments of chemicals are routinely performed using in vivo data from rodents; however, there is growing recognition that non-animal approaches can be human-relevant alternatives. There is an urgent need to build confidence in non-animal alternatives given the international support to reduce the use of animals in toxicity testing where possible. In order for scientists and risk assessors to prepare for this paradigm shift in toxicity assessment, standardization and consensus on in vitro testing strategies and data interpretation will need to be established. To address this issue, an Expert Working Group (EWG) of the 8th International Workshop on Genotoxicity Testing (IWGT) evaluated the utility of quantitative in vitro genotoxicity concentration-response data for risk assessment. The EWG first evaluated available in vitro methodologies and then examined the variability and maximal response of in vitro tests to estimate biologically relevant values for the critical effect sizes considered adverse or unacceptable. Next, the EWG reviewed the approaches and computational models employed to provide human-relevant dose context to in vitro data. Lastly, the EWG evaluated risk assessment applications for which in vitro data are ready for use and applications where further work is required. The EWG concluded that in vitro genotoxicity concentration-response data can be interpreted in a risk assessment context. However, prior to routine use in regulatory settings, further research will be required to address the remaining uncertainties and limitations.
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Affiliation(s)
- Marc A Beal
- Bureau of Chemical Safety, Health Products and Food Branch, Health Canada, Ottawa, Ontario, Canada
| | - Guangchao Chen
- Centre for Nutrition, Prevention and Health Services, National Institute for Public Health and the Environment (RIVM), Utrecht, the Netherlands
| | - Kerry L Dearfield
- Retired from US Environmental Protection Agency and US Department of Agriculture, Washington, DC, USA
| | - Min Gi
- Department of Environmental Risk Assessment, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | | | - Robert H Heflich
- National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas, USA
| | - Katsuyoshi Horibata
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, Kawasaki, Kanagawa, Japan
| | - Alexandra S Long
- Existing Substances Risk Assessment Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
| | - David P Lovell
- St George's Medical School, University of London, London, UK
| | - Barbara L Parsons
- National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas, USA
| | - Stefan Pfuhler
- Global Product Stewardship - Human Safety, Procter & Gamble, Cincinnati, Ohio, USA
| | - John Wills
- Genetic Toxicology and Photosafety, GSK Research & Development, Stevenage, UK
| | - Andreas Zeller
- Pharmaceutical Sciences, pRED Innovation Center Basel, Hoffmann-La Roche Ltd, Basel, Switzerland
| | - George Johnson
- Swansea University Medical School, Swansea University, Swansea, UK
| | - Paul A White
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
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Smith-Roe SL, Hobbs CA, Hull V, Todd Auman J, Recio L, Streicker MA, Rivas MV, Pratt GA, Lo FY, Higgins JE, Schmidt EK, Williams LN, Nachmanson D, Valentine Iii CC, Salk JJ, Witt KL. Adopting duplex sequencing technology for genetic toxicity testing: A proof-of-concept mutagenesis experiment with N-ethyl-N-nitrosourea (ENU)-exposed rats. MUTATION RESEARCH. GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2023; 891:503669. [PMID: 37770135 PMCID: PMC10539650 DOI: 10.1016/j.mrgentox.2023.503669] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 07/31/2023] [Accepted: 08/01/2023] [Indexed: 09/30/2023]
Abstract
Duplex sequencing (DS) is an error-corrected next-generation sequencing method in which molecular barcodes informatically link PCR-copies back to their source DNA strands, enabling computational removal of errors in consensus sequences. The resulting background of less than one artifactual mutation per 107 nucleotides allows for direct detection of somatic mutations. TwinStrand Biosciences, Inc. has developed a DS-based mutagenesis assay to sample the rat genome, which can be applied to genetic toxicity testing. To evaluate this assay for early detection of mutagenesis, a time-course study was conducted using male Hsd:Sprague Dawley SD rats (3 per group) administered a single dose of 40 mg/kg N-ethyl-N-nitrosourea (ENU) via gavage, with mutation frequency (MF) and spectrum analyzed in stomach, bone marrow, blood, and liver tissues at 3 h, 24 h, 7 d, and 28 d post-exposure. Significant increases in MF were observed in ENU-exposed rats as early as 24 h for stomach (site of contact) and bone marrow (a highly proliferative tissue) and at 7 d for liver and blood. The canonical, mutational signature of ENU was established by 7 d post-exposure in all four tissues. Interlaboratory analysis of a subset of samples from different tissues and time points demonstrated remarkable reproducibility for both MF and spectrum. These results demonstrate that MF and spectrum can be evaluated successfully by directly sequencing targeted regions of DNA obtained from various tissues, a considerable advancement compared to currently used in vivo gene mutation assays.
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Affiliation(s)
| | - Cheryl A Hobbs
- Integrated Laboratory Systems, LLC (An Inotiv Company), Research Triangle Park, NC, USA
| | - Victoria Hull
- Integrated Laboratory Systems, LLC (An Inotiv Company), Research Triangle Park, NC, USA
| | - J Todd Auman
- Integrated Laboratory Systems, LLC (An Inotiv Company), Research Triangle Park, NC, USA
| | - Leslie Recio
- Integrated Laboratory Systems, LLC (An Inotiv Company), Research Triangle Park, NC, USA
| | - Michael A Streicker
- Integrated Laboratory Systems, LLC (An Inotiv Company), Research Triangle Park, NC, USA
| | - Miriam V Rivas
- Integrated Laboratory Systems, LLC (An Inotiv Company), Research Triangle Park, NC, USA
| | | | - Fang Yin Lo
- TwinStrand Biosciences, Inc., Seattle, WA, USA
| | | | | | | | | | | | | | - Kristine L Witt
- Division of Translational Toxicology, NIEHS, Research Triangle Park, NC, USA
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Marchetti F, Cardoso R, Chen CL, Douglas GR, Elloway J, Escobar PA, Harper T, Heflich RH, Kidd D, Lynch AM, Myers MB, Parsons BL, Salk JJ, Settivari RS, Smith-Roe SL, Witt KL, Yauk CL, Young R, Zhang S, Minocherhomji S. Error-corrected next generation sequencing - Promises and challenges for genotoxicity and cancer risk assessment. MUTATION RESEARCH. REVIEWS IN MUTATION RESEARCH 2023; 792:108466. [PMID: 37643677 DOI: 10.1016/j.mrrev.2023.108466] [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: 03/09/2023] [Revised: 07/12/2023] [Accepted: 08/23/2023] [Indexed: 08/31/2023]
Abstract
Error-corrected Next Generation Sequencing (ecNGS) is rapidly emerging as a valuable, highly sensitive and accurate method for detecting and characterizing mutations in any cell type, tissue or organism from which DNA can be isolated. Recent mutagenicity and carcinogenicity studies have used ecNGS to quantify drug-/chemical-induced mutations and mutational spectra associated with cancer risk. ecNGS has potential applications in genotoxicity assessment as a new readout for traditional models, for mutagenesis studies in 3D organotypic cultures, and for detecting off-target effects of gene editing tools. Additionally, early data suggest that ecNGS can measure clonal expansion of mutations as a mechanism-agnostic early marker of carcinogenic potential and can evaluate mutational load directly in human biomonitoring studies. In this review, we discuss promising applications, challenges, limitations, and key data initiatives needed to enable regulatory testing and adoption of ecNGS - including for advancing safety assessment, augmenting weight-of-evidence for mutagenicity and carcinogenicity mechanisms, identifying early biomarkers of cancer risk, and managing human health risk from chemical exposures.
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Affiliation(s)
| | | | - Connie L Chen
- Health and Environmental Sciences Institute, Washington, DC, USA.
| | | | - Joanne Elloway
- Safety Sciences, Clinical Pharmacology & Safety Sciences, R&D, AstraZeneca, Cambridge, UK
| | | | - Tod Harper
- Amgen Research, Amgen Inc, Thousand Oaks, CA, USA
| | - Robert H Heflich
- US Food and Drug Administration/National Center for Toxicological Research, Jefferson, AR, USA
| | - Darren Kidd
- Labcorp Early Development Laboratories Limited, Harrogate, North Yorkshire, UK
| | | | - Meagan B Myers
- US Food and Drug Administration/National Center for Toxicological Research, Jefferson, AR, USA
| | - Barbara L Parsons
- US Food and Drug Administration/National Center for Toxicological Research, Jefferson, AR, USA
| | | | | | | | - Kristine L Witt
- NIEHS, Division of the National Toxicology Program, Research Triangle Park, NC, USA
| | | | - Robert Young
- MilliporeSigma, Rockville, MD, USA; Current: Consultant, Bethesda, MD, USA
| | | | - Sheroy Minocherhomji
- Amgen Research, Amgen Inc, Thousand Oaks, CA, USA; Current: Eli Lilly and Company, Indianapolis, IN, USA
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5
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Smith-Roe SL, Hobbs CA, Hull V, Auman JT, Recio L, Streicker MA, Rivas MV, Pratt GA, Lo FY, Higgins JE, Schmidt EK, Williams LN, Nachmanson D, Valentine CC, Salk JJ, Witt KL. Adopting Duplex Sequencing™ Technology for Genetic Toxicity Testing: A Proof-of-Concept Mutagenesis Experiment with N-Ethyl-N-Nitrosourea (ENU)-Exposed Rats. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.08.539833. [PMID: 37214853 PMCID: PMC10197591 DOI: 10.1101/2023.05.08.539833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Duplex sequencing (DuplexSeq) is an error-corrected next-generation sequencing (ecNGS) method in which molecular barcodes informatically link PCR-copies back to their source DNA strands, enabling computational removal of errors by comparing grouped strand sequencing reads. The resulting background of less than one artifactual mutation per 10 7 nucleotides allows for direct detection of somatic mutations. TwinStrand Biosciences, Inc. has developed a DuplexSeq-based mutagenesis assay to sample the rat genome, which can be applied to genetic toxicity testing. To evaluate this assay for early detection of mutagenesis, a time-course study was conducted using male Hsd:Sprague Dawley SD rats (3 per group) administered a single dose of 40 mg/kg N-ethyl-N-nitrosourea (ENU) via gavage, with mutation frequency (MF) and spectrum analyzed in stomach, bone marrow, blood, and liver tissues at 3 h, 24 h, 7 d, and 28 d post-exposure. Significant increases in MF were observed in ENU-exposed rats as early as 24 h for stomach (site of contact) and bone marrow (a highly proliferative tissue) and at 7 d for liver and blood. The canonical, mutational signature of ENU was established by 7 d post-exposure in all four tissues. Interlaboratory analysis of a subset of samples from different tissues and time points demonstrated remarkable reproducibility for both MF and spectrum. These results demonstrate that MF and spectrum can be evaluated successfully by directly sequencing targeted regions of DNA obtained from various tissues, a considerable advancement compared to currently used in vivo gene mutation assays. HIGHLIGHTS DuplexSeq is an ultra-accurate NGS technology that directly quantifies mutationsENU-dependent mutagenesis was detected 24 h post-exposure in proliferative tissuesMultiple tissues exhibited the canonical ENU mutation spectrum 7 d after exposureResults obtained with DuplexSeq were highly concordant between laboratoriesThe Rat-50 Mutagenesis Assay is promising for applications in genetic toxicology.
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Affiliation(s)
| | - Cheryl A. Hobbs
- Integrated Laboratory Systems, LLC (an Inotiv company), Research Triangle Park, NC
| | - Victoria Hull
- Integrated Laboratory Systems, LLC (an Inotiv company), Research Triangle Park, NC
| | - J. Todd Auman
- Integrated Laboratory Systems, LLC (an Inotiv company), Research Triangle Park, NC
| | - Leslie Recio
- Integrated Laboratory Systems, LLC (an Inotiv company), Research Triangle Park, NC
| | - Michael A. Streicker
- Integrated Laboratory Systems, LLC (an Inotiv company), Research Triangle Park, NC
| | - Miriam V. Rivas
- Integrated Laboratory Systems, LLC (an Inotiv company), Research Triangle Park, NC
| | | | | | | | | | | | | | | | | | - Kristine L. Witt
- Division of Translational Toxicology, NIEHS, Research Triangle Park, NC
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6
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Landsiedel R, Honarvar N, Seiffert SB, Oesch B, Oesch F. Genotoxicity testing of nanomaterials. WIRES NANOMEDICINE AND NANOBIOTECHNOLOGY 2022; 14:e1833. [DOI: 10.1002/wnan.1833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 06/02/2022] [Accepted: 06/06/2022] [Indexed: 11/24/2022]
Affiliation(s)
- Robert Landsiedel
- Experimental Toxicology and Ecology BASF SE Ludwigshafen am Rhein Germany
- Pharmacy, Pharmacology and Toxicology Free University of Berlin Berlin Germany
| | - Naveed Honarvar
- Experimental Toxicology and Ecology BASF SE Ludwigshafen am Rhein Germany
| | | | - Barbara Oesch
- Oesch‐Tox Toxicological Consulting and Expert Opinions, GmbH & Co KG Ingelheim Germany
| | - Franz Oesch
- Oesch‐Tox Toxicological Consulting and Expert Opinions, GmbH & Co KG Ingelheim Germany
- Institute of Toxicology Johannes Gutenberg University Mainz Germany
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7
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Kuo B, Beal MA, Wills JW, White PA, Marchetti F, Nong A, Barton-Maclaren TS, Houck K, Yauk CL. Comprehensive interpretation of in vitro micronucleus test results for 292 chemicals: from hazard identification to risk assessment application. Arch Toxicol 2022; 96:2067-2085. [PMID: 35445829 PMCID: PMC9151546 DOI: 10.1007/s00204-022-03286-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 02/23/2022] [Indexed: 11/08/2022]
Abstract
Risk assessments are increasingly reliant on information from in vitro assays. The in vitro micronucleus test (MNvit) is a genotoxicity test that detects chromosomal abnormalities, including chromosome breakage (clastogenicity) and/or whole chromosome loss (aneugenicity). In this study, MNvit datasets for 292 chemicals, generated by the US EPA's ToxCast program, were evaluated using a decision tree-based pipeline for hazard identification. Chemicals were tested with 19 concentrations (n = 1) up to 200 µM, in the presence and absence of Aroclor 1254-induced rat liver S9. To identify clastogenic chemicals, %MN values at each concentration were compared to a distribution of batch-specific solvent controls; this was followed by cytotoxicity assessment and benchmark concentration (BMC) analyses. The approach classified 157 substances as positives, 25 as negatives, and 110 as inconclusive. Using the approach described in Bryce et al. (Environ Mol Mutagen 52:280-286, 2011), we identified 15 (5%) aneugens. IVIVE (in vitro to in vivo extrapolation) was employed to convert BMCs into administered equivalent doses (AEDs). Where possible, AEDs were compared to points of departure (PODs) for traditional genotoxicity endpoints; AEDs were generally lower than PODs based on in vivo endpoints. To facilitate interpretation of in vitro MN assay concentration-response data for risk assessment, exposure estimates were utilized to calculate bioactivity exposure ratio (BER) values. BERs for 50 clastogens and two aneugens had AEDs that approached exposure estimates (i.e., BER < 100); these chemicals might be considered priorities for additional testing. This work provides a framework for the use of high-throughput in vitro genotoxicity testing for priority setting and chemical risk assessment.
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Affiliation(s)
- Byron Kuo
- Environmental Health Science and Research Bureau, Environmental and Radiation Health Sciences Directorate, Healthy Environment and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada
| | - Marc A Beal
- Bureau of Chemical Safety, Food Directorate, Health Products and Food Branch, Health Canada, Ottawa, ON, Canada
| | - John W Wills
- Environmental Health Science and Research Bureau, Environmental and Radiation Health Sciences Directorate, Healthy Environment and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada
- Biominerals Research, Department of Veterinary Medicine, University of Cambridge, Cambridge, CB3 0ES, UK
| | - Paul A White
- Environmental Health Science and Research Bureau, Environmental and Radiation Health Sciences Directorate, Healthy Environment and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada
| | - Francesco Marchetti
- Environmental Health Science and Research Bureau, Environmental and Radiation Health Sciences Directorate, Healthy Environment and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada
| | - Andy Nong
- Environmental Health Science and Research Bureau, Environmental and Radiation Health Sciences Directorate, Healthy Environment and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada
| | - Tara S Barton-Maclaren
- Existing Substances Risk Assessment Bureau, Safe Environments Directorate, Healthy Environment and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada
| | - Keith Houck
- National Center for Computational Toxicology, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, 27711, USA
| | - Carole L Yauk
- Environmental Health Science and Research Bureau, Environmental and Radiation Health Sciences Directorate, Healthy Environment and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada.
- Department of Biology, University of Ottawa, 30 Marie Curie Private, Room 269, Ottawa, ON, K1N 6N5, Canada.
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Zhou CH, Yu CR, Huang PC, Li RW, Wang JT, Zhao TT, Zhao ZH, Ma J, Chang Y. In Vitro PIG-A Gene Mutation Assay in Human B-Lymphoblastoid TK6 Cells. PHARMACEUTICAL FRONTS 2021. [DOI: 10.1055/s-0041-1735146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
AbstractThe X-linked PIG-A gene is involved in the biosynthesis of glycosylphosphatidylinositol (GPI) anchors. PIG-A mutant cells fail to synthesize GPI and to express GPI-anchored protein markers (e.g., CD59 and CD55). In recent years, in vitro PIG-A assay has been established based on the high conservation of PIG-A/Pig-a loci among different species and the large data from the in vivo system. The purpose of this study was to extend the approach for PIG-A mutation assessment to in vitro human B-lymphoblastoid TK6 cells by detecting the loss of GPI-linked CD55 and CD59 proteins. TK6 cells were treated with three mutagens 7,12-dimethylbenz[a]anthracene (DMBA), N-ethyl-N-nitrosourea (ENU), etoposide (ETO), and two nonmutagens: cadmium chloride (CdCl2) and sodium chloride (NaCl). The mutation rate of PIG-A gene within TK6 cells was determined on the 11th day with flow cytometry analysis for the negative frequencies of CD55 and CD59. The antibodies used in this production were APC mouse-anti-human CD19 antibody, PE mouse anti-human CD55 antibody, PE mouse anti-human CD59 antibody, and nucleic acid dye 7-AAD. An immunolabeling method was used to reduce the high spontaneous level of preexisting PIG-A mutant cells. Our data suggested that DMBA-, ENU-, and ETO-induced mutation frequency of PIG-A gene was increased by twofold compared with the negative control, and the effects were dose-dependent. However, CdCl2 and NaCl did not significantly increase the mutation frequency of PIG-A gene, with a high cytotoxicity at a dose of 10 mmol/L. Our study suggested that the novel in vitro PIG-A gene mutation assay within TK6 cells may represent a complement of the present in vivo Pig-a assay, and may provide guidance for their potential use in genotoxicity even in cells with a significant deficiency of GPI anchor.
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Affiliation(s)
- Chang-Hui Zhou
- Shanghai Innostar Bio-tech Co., Ltd., China State Institute of Pharmaceutical Industry, Shanghai, People's Republic of China
| | - Chun-Rong Yu
- Shanghai Innostar Bio-tech Co., Ltd., China State Institute of Pharmaceutical Industry, Shanghai, People's Republic of China
| | - Peng-Cheng Huang
- Shanghai Innostar Bio-tech Co., Ltd., China State Institute of Pharmaceutical Industry, Shanghai, People's Republic of China
| | - Ruo-Wan Li
- Shanghai Innostar Bio-tech Co., Ltd., China State Institute of Pharmaceutical Industry, Shanghai, People's Republic of China
| | - Jing-Ting Wang
- Shanghai Innostar Bio-tech Co., Ltd., China State Institute of Pharmaceutical Industry, Shanghai, People's Republic of China
| | - Tian-Tian Zhao
- Shanghai Innostar Bio-tech Co., Ltd., China State Institute of Pharmaceutical Industry, Shanghai, People's Republic of China
| | - Ze-Hao Zhao
- Shanghai Innostar Bio-tech Co., Ltd., China State Institute of Pharmaceutical Industry, Shanghai, People's Republic of China
| | - Jing Ma
- Shanghai Innostar Bio-tech Co., Ltd., China State Institute of Pharmaceutical Industry, Shanghai, People's Republic of China
| | - Yan Chang
- Shanghai Innostar Bio-tech Co., Ltd., China State Institute of Pharmaceutical Industry, Shanghai, People's Republic of China
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9
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Li D, Sun X, Yu F, Perle MA, Araten D, Boeke J. Application of counter-selectable marker PIGA in engineering designer deletion cell lines and characterization of CRISPR deletion efficiency. Nucleic Acids Res 2021; 49:2642-2654. [PMID: 33591308 PMCID: PMC7969003 DOI: 10.1093/nar/gkab035] [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: 09/08/2020] [Revised: 01/11/2021] [Accepted: 02/15/2021] [Indexed: 12/18/2022] Open
Abstract
The CRISPR/Cas9 system is a technology for genome engineering, which has been applied to indel mutations in genes as well as targeted gene deletion and replacement. Here, we describe paired gRNA deletions along the PIGA locus on the human X chromosome ranging from 17 kb to 2 Mb. We found no compelling linear correlation between deletion size and the deletion efficiency, and there is no substantial impact of topologically associating domains on deletion frequency. Using this precise deletion technique, we have engineered a series of designer deletion cell lines, including one with deletions of two X-chromosomal counterselectable (negative selection) markers, PIGA and HPRT1, and additional cell lines bearing each individual deletion. PIGA encodes a component of the glycosylphosphatidylinositol (GPI) anchor biosynthetic apparatus. The PIGA gene counterselectable marker has unique features, including existing single cell level assays for both function and loss of function of PIGA and the existence of a potent counterselectable agent, proaerolysin, which we use routinely for selection against cells expressing PIGA. These designer cell lines may serve as a general platform with multiple selection markers and may be particularly useful for large scale genome engineering projects such as Genome Project-Write (GP-write).
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Affiliation(s)
- Donghui Li
- Institute for Systems Genetics and Department of Biochemistry & Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Xiaoji Sun
- Institute for Systems Genetics and Department of Biochemistry & Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA
| | - Fangzhou Yu
- Institute for Systems Genetics and Department of Biochemistry & Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA
| | - Mary Ann Perle
- Department of Pathology, NYU Langone Health, New York, NY 10016, USA
| | - David Araten
- Division of Hematology, Laura and Isaac Perlmutter Cancer Center, NYU Langone Health, and the New York VA Medical Center, New York, NY 10016, USA
| | - Jef D Boeke
- Institute for Systems Genetics and Department of Biochemistry & Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA
- Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn NY 11201, USA
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10
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The IWGT in vitro Mammalian Cell Gene Mutation (MCGM) assays working group—Introductory remarks & consensus statements. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2019; 848:403061. [DOI: 10.1016/j.mrgentox.2019.05.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 05/29/2019] [Accepted: 05/30/2019] [Indexed: 01/21/2023]
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