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Standards for Quantitative Measurement of DNA Damage in Mammalian Cells. Int J Mol Sci 2023; 24:ijms24065427. [PMID: 36982502 PMCID: PMC10051712 DOI: 10.3390/ijms24065427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/07/2023] [Accepted: 03/09/2023] [Indexed: 03/18/2023] Open
Abstract
As the potential applications of DNA diagnostics continue to expand, there is a need for improved methods and standards for DNA analysis. This report describes several methods that could be considered for the production of reference materials for the quantitative measurement of DNA damage in mammalian cells. With the focus on DNA strand breaks, potentially useful methods for assessing DNA damage in mammalian cells are reviewed. The advantages and limitations of each method, as well as additional concerns with respect to reference material development, are also discussed. In conclusion, we outline strategies for developing candidate DNA damage reference materials that could be adopted by research laboratories in a wide variety of applications.
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Development of a Reference Method and Materials for Quantitative Measurement of UV-Induced DNA Damage in Mammalian Cells: Comparison of Comet Assay and Cell Viability. J Nucleic Acids 2022; 2022:9188636. [PMID: 36164440 PMCID: PMC9509282 DOI: 10.1155/2022/9188636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/06/2022] [Accepted: 08/27/2022] [Indexed: 11/17/2022] Open
Abstract
Application of DNA damage diagnostic tests is rapidly growing, in particular for ovarian, prostate, and skin cancers; environmental monitoring; chronic and degenerative diseases; and male infertility. Such tests suffer from significant variability among different laboratories due the lack of standardization, experimental validation, and differences in data interpretation. Reference methods and materials for quantitative measurement of UVA-induced DNA damage in mammalian cells are frequently needed. In this study, we examined the use of the single-cell gel electrophoresis (comet) assay to assess the UVA-induced DNA damage in surface-attached Chinese hamster ovary (CHO) cells treated with a photosensitizer as a candidate cellular oxidative damage reference material. We found that the comet images became diffused and the viability of the cells decreased substantially (>20%) as the UVA dose and benzo [a] pyrene (BaP) concentration exceeded 6.3 J/cm2 and 10−6 mol/L BaP. Maintaining the conditions of exposure within this range can improve DNA damage measurement fidelity, particularly if used as a quantitative reference method and to produce materials considered as an in vitro standard for the comet assay.
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Atha DH, Coskun E, Erdem O, Tona A, Reipa V, Nelson BC. Genotoxic Effects of Etoposide, Bleomycin, and Ethyl Methanesulfonate on Cultured CHO Cells: Analysis by GC-MS/MS and Comet Assay. J Nucleic Acids 2020; 2020:8810105. [PMID: 32802493 PMCID: PMC7414336 DOI: 10.1155/2020/8810105] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 06/13/2020] [Accepted: 07/07/2020] [Indexed: 01/13/2023] Open
Abstract
To evaluate methods for analysis of genotoxic effects on mammalian cell lines, we tested the effect of three common genotoxic agents on Chinese hamster ovary (CHO) cells by single-cell gel electrophoresis (comet assay) and gas chromatography-tandem mass spectrometry (GC-MS/MS). Suspension-grown CHO cells were separately incubated with etoposide, bleomycin, and ethyl methanesulfonate and analyzed by an alkaline comet assay and GC-MS/MS. Although DNA strand breaks were detected by the comet assay after treatment with all three agents, GC-MS/MS could only detect DNA nucleobase lesions oxidatively induced by bleomycin. This demonstrates that although GC-MS/MS has limitations in detection of genotoxic effects, it can be used for selected chemical genotoxins that contribute to oxidizing processes. The comet assay, used in combination with GC-MS/MS, can be a more useful approach to screen a wide range of chemical genotoxins as well as to monitor other DNA-damaging factors.
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Affiliation(s)
- Donald H. Atha
- National Institute of Standards and Technology, Biosystems and Biomaterials Division, Materials Measurement Laboratory, Gaithersburg, MD 20899, USA
| | - Erdem Coskun
- National Institute of Standards and Technology, Biomolecular Measurement Division, Materials Measurement Laboratory, Gaithersburg, MD 20899, USA
- University of Maryland, Institute for Bioscience and Biotechnology Research, Rockville, MD 20850, USA
| | - Onur Erdem
- National Institute of Standards and Technology, Biomolecular Measurement Division, Materials Measurement Laboratory, Gaithersburg, MD 20899, USA
- University of Health Sciences Turkey, Department of Pharmaceutical Toxicology, Gulhane Faculty of Pharmacy, 06010 Ankara, Turkey
| | - Alessandro Tona
- National Institute of Standards and Technology, Biosystems and Biomaterials Division, Materials Measurement Laboratory, Gaithersburg, MD 20899, USA
| | - Vytas Reipa
- National Institute of Standards and Technology, Biosystems and Biomaterials Division, Materials Measurement Laboratory, Gaithersburg, MD 20899, USA
| | - Bryant C. Nelson
- National Institute of Standards and Technology, Biosystems and Biomaterials Division, Materials Measurement Laboratory, Gaithersburg, MD 20899, USA
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