1
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Allemang A, Lester C, Roth T, Pfuhler S, Peuschel H, Kosemund K, Mahony C, Bergeland T, O'Keeffe L. Assessing the genotoxicity and carcinogenicity of 2-chloroethanol through structure activity relationships and in vitro testing approaches. Food Chem Toxicol 2022; 168:113290. [PMID: 35863484 DOI: 10.1016/j.fct.2022.113290] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 06/16/2022] [Accepted: 07/08/2022] [Indexed: 11/25/2022]
Abstract
The detection of 2-chloroethanol in foods generally follows an assumption that the pesticide ethylene oxide has been used at some stage in the supply chain. In this situation the Pesticide Residues in Food Regulation (EC) 396/2005 requires 2-chloroethanol to be assessed as if equivalent to ethylene oxide, which has been classified as a genotoxic carcinogen. This review investigated whether this is an appropriate risk assessment approach for 2-chloroethanol. This involved an assessment of existing genotoxicity and carcinogenicity data, application of Structure Activity Based Read Across for carcinogenicity assessment, biological reactivity in the ToxTracker assay and micronuclei formation in HepaRG cells. Although we identified there is an absence of a standard oral bioassay for 2-chloroethanol, carcinogenicity weight-of-evidence assessment along with data on relevant structural analogues do not show evidence for carcinogenicity for 2-chloroethanol. The absence of genotoxicity was demonstrated for 2-chloroethanol and suitable analogues. In contrast, ethylene oxide showed reactivity towards markers indicative of direct DNA damage which is consistent with what is known about its mode-of-action. These data facilitate the understanding of 2-chloroethanol and given that it is not a genotoxic carcinogen suggest it must be assessed relative to non-cancer endpoints and a health protective Reference Dose should be established on that basis.
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Affiliation(s)
| | - Cathy Lester
- The Procter & Gamble Company, Cincinnati, OH, USA
| | - Thomas Roth
- SCC Scientific Consulting Company GmbH, Am Grenzgraben 11, 55545, Bad Kreuznach, Germany
| | | | - Henrike Peuschel
- SCC Scientific Consulting Company GmbH, Am Grenzgraben 11, 55545, Bad Kreuznach, Germany
| | - Kirstin Kosemund
- Procter & Gamble Service GmbH, Sulzbacher Str. 40, 65824, Schwalbach am Taunus, Germany
| | | | | | - Lara O'Keeffe
- The Procter & Gamble Company, Reading, Berkshire, UK.
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2
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Tang Y, Zhang JL. Recent developments in DNA adduct analysis using liquid chromatography coupled with mass spectrometry. J Sep Sci 2019; 43:31-55. [PMID: 31573133 DOI: 10.1002/jssc.201900737] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 09/04/2019] [Accepted: 09/27/2019] [Indexed: 12/15/2022]
Abstract
The formation of DNA adducts by genotoxic agents is an early event in cancer development, and it may lead to gene mutations, thereby initiating tumor development. The measurement of DNA adducts can provide critical information about the genotoxic potential of a chemical and its mechanism of carcinogenesis. In recent decades, liquid chromatography coupled with mass spectrometry has become the most important technique for analyzing DNA adducts. The improvements in resolution achievable with new chromatographic separation techniques coupled with the high specificity and sensitivity and wide dynamic range of new mass spectrometry systems have been used for both qualitative and quantitative analyses of DNA adducts. This review discusses the challenges in qualitative and quantitative analyses of DNA adducts by liquid chromatography coupled with mass spectrometry and highlights recent developments towards overcoming the limitations of liquid chromatography coupled with mass spectrometry methods. The key steps and new solutions, such as sample preparation, mass spectrometry fragmentation, and method validation, are summarized. In addition, the fundamental principles and latest advances in DNA adductomic approaches are reviewed.
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Affiliation(s)
- Yu Tang
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing, P. R. China
| | - Jin-Lan Zhang
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing, P. R. China
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3
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Pottenger LH, Boysen G, Brown K, Cadet J, Fuchs RP, Johnson GE, Swenberg JA. Understanding the importance of low-molecular weight (ethylene oxide- and propylene oxide-induced) DNA adducts and mutations in risk assessment: Insights from 15 years of research and collaborative discussions. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2019; 60:100-121. [PMID: 30536466 PMCID: PMC6590209 DOI: 10.1002/em.22248] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 08/10/2018] [Accepted: 08/23/2018] [Indexed: 05/11/2023]
Abstract
The interpretation and significance of DNA adduct data, their causal relationship to mutations, and their role in risk assessment have been debated for many years. An extended effort to identify key questions and collect relevant data to address them was focused on the ubiquitous low MW N7-alkyl/hydroxyalkylguanine adducts. Several academic, governmental, and industrial laboratories collaborated to gather new data aimed at better understanding the role and potential impact of these adducts in quantifiable genotoxic events (gene mutations/micronucleus). This review summarizes and evaluates the status of dose-response data for DNA adducts and mutations from recent experimental work with standard mutagenic agents and ethylene oxide and propylene oxide, and the importance for risk assessment. This body of evidence demonstrates that small N7-alkyl/hydroxyalkylguanine adducts are not pro-mutagenic and, therefore, adduct formation alone is not adequate evidence to support a mutagenic mode of action. Quantitative methods for dose-response analysis and derivation of thresholds, benchmark dose (BMD), or other points-of-departure (POD) for genotoxic events are now available. Integration of such analyses of genetox data is necessary to properly assess any role for DNA adducts in risk assessment. Regulatory acceptance and application of these insights remain key challenges that only the regulatory community can address by applying the many learnings from recent research. The necessary tools, such as BMDs and PODs, and the example datasets, are now available and sufficiently mature for use by the regulatory community. Environ. Mol. Mutagen. 60: 100-121, 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)
- L. H. Pottenger
- Olin Corporation/Blue Cube Operations, LLC, retired, LHP TOX CONSULT, LLCMidlandMIUSA
| | - G. Boysen
- Department of Environmental and Occupational Health and The Winthrop P Rockefeller Cancer Institute University of Arkansas for Medical SciencesLittle RockArkansasUSA
| | - K. Brown
- Leicester Cancer Research CentreUniversity of LeicesterLeicesterUnited Kingdom
| | - J. Cadet
- Institut Nanosciences et Cryogénie, CEA‐GrenobleGrenobleFrance
- Université de SherbrookeSherbrookeCanada
| | - R. P. Fuchs
- Centre de Recherche en Cancérologie de Marseille (CRCM), Inserm, U1068Marseille, 13009France
- CNRS, UMR7258Marseille, 13009France
- Institut Paoli‐CalmettesMarseille, 13009France
- Aix‐Marseille UniversityUM 105, 13284, MarseilleFrance
| | - G. E. Johnson
- Swansea University, Institute of Life SciencesSwanseaUnited Kingdom
| | - J. A. Swenberg
- University of North CarolinaChapel HillNorth CarolinaUSA
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4
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Improving risk assessment approaches for chemicals with both endogenous and exogenous exposures. Regul Toxicol Pharmacol 2019; 103:210-215. [PMID: 30703408 DOI: 10.1016/j.yrtph.2019.01.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Revised: 01/17/2019] [Accepted: 01/20/2019] [Indexed: 02/02/2023]
Abstract
To conduct risk assessments of exogenous chemicals for which there are also endogenous exposures, knowledge of the chemistry and biology of both types of exposures needs to be integrated into problem formulation and carried through to risk characterization. This issue is framed in a risk assessment context, highlighting the importance of quantifying increments of dose from all sources of the same or similar chemicals interacting with biological targets; understanding the influence of endogenous chemical concentrations on disease risk; and assessing total dose to targets in evaluating risk from incremental environmental exposures. Examples of recent assessments illustrate the importance of addressing this issue. Evaluations of data on blood or organ concentrations of ammonia, methanol, formaldehyde, acetaldehyde, and three gaseous signaling molecules (hydrogen sulfide, carbon monoxide, and nitric oxide) provide examples where current data are already informing perspectives on relative exposures at the portal of entry and systemically. To facilitate quality risk assessments of exogenous chemicals with endogenous exposures, a series of specific questions are presented that need to be addressed in systematic review to enhance problem formulation, improve the development of holistic conceptual models, and to facilitate the identification of priority data needs for improving risk assessments.
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5
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Jinot J, Fritz JM, Vulimiri SV, Keshava N. Carcinogenicity of ethylene oxide: key findings and scientific issues. Toxicol Mech Methods 2018; 28:386-396. [PMID: 29210319 PMCID: PMC10883472 DOI: 10.1080/15376516.2017.1414343] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 12/04/2017] [Indexed: 12/26/2022]
Abstract
In support of the Integrated Risk Information System (IRIS), the U.S. Environmental Protection Agency (EPA) completed an evaluation of the inhalation carcinogenicity of ethylene oxide (EtO) in December 2016. This article reviews key findings and scientific issues regarding the carcinogenicity of EtO in EPA's Carcinogenicity Assessment. EPA's assessment critically reviewed and characterized epidemiologic, laboratory animal, and mechanistic studies pertaining to the human carcinogenicity of EtO, and addressed some key scientific issues such as the analysis of mechanistic data as part of the cancer hazard evaluation and to inform the quantitative risk assessment. The weight of evidence from the epidemiologic, laboratory animal, and mechanistic studies supports a conclusion that EtO is carcinogenic in humans, with the strongest human evidence linking EtO exposure to lymphoid and breast cancers. Analyses of the mechanistic data establish a key role for genotoxicity and mutagenicity in EtO-induced carcinogenicity and reveal little evidence supporting other mode-of-action hypotheses. In conclusion, EtO was found to be carcinogenic to humans by inhalation, posing a potential human health hazard for lymphoid and breast cancers.
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Affiliation(s)
- Jennifer Jinot
- a National Center for Environmental Assessment , U.S. Environmental Protection Agency , Washington , DC , USA
| | - Jason M Fritz
- a National Center for Environmental Assessment , U.S. Environmental Protection Agency , Washington , DC , USA
| | - Suryanarayana V Vulimiri
- a National Center for Environmental Assessment , U.S. Environmental Protection Agency , Washington , DC , USA
| | - Nagalakshmi Keshava
- a National Center for Environmental Assessment , U.S. Environmental Protection Agency , Washington , DC , USA
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6
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Michel AK, Zarth AT, Upadhyaya P, Hecht SS. Identification of 4-(3-Pyridyl)-4-oxobutyl-2'-deoxycytidine Adducts Formed in the Reaction of DNA with 4-(Acetoxymethylnitrosamino)-1-(3-pyridyl)-1-butanone: A Chemically Activated Form of Tobacco-Specific Carcinogens. ACS OMEGA 2017; 2:1180-1190. [PMID: 28393135 PMCID: PMC5377278 DOI: 10.1021/acsomega.7b00072] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 03/14/2017] [Indexed: 06/07/2023]
Abstract
Metabolic activation of the carcinogenic tobacco-specific nitrosamines 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK, 1) and N'-nitrosonornicotine (NNN, 2) results in the formation of 4-(3-pyridyl)-4-oxobutyl (POB)-DNA adducts, several of which have been previously identified both in vitro and in tissues of laboratory animals treated with NNK or NNN. However, 2'-deoxycytidine adducts formed in this process have been incompletely examined in previous studies. Therefore, in this study we prepared characterized standards for the identification of previously unknown 2'-deoxycytidine and 2'-deoxyuridine adducts that could be produced in these reactions. The formation of these products in reactions of 4-(acetoxymethylnitrosamino)-1-(3-pyridyl)-1-butanone (NNKOAc, 3), a model 4-(3-pyridyl)-4-oxobutylating agent, with DNA was investigated. The major 2'-deoxycytidine adduct, identified as its stable cytosine analogue O2-[4-(3-pyridyl)-4-oxobut-1-yl]-cytosine (12), was O2-[4-(3-pyridyl)-4-oxobut-1-yl]-2'-deoxycytidine (13), whereas lesser amounts of 3-[4-(3-pyridyl)-4-oxobut-1-yl]-2'-deoxycytidine (14) and N4-[4-(3-pyridyl)-4-oxobut-1-yl]-2'-deoxycytidine (15) were also observed. The potential conversion of relatively unstable 2'-deoxycytidine adducts to stable 2'-deoxyuridine adducts by treatment of the adducted DNA with bisulfite was also investigated, but the harsh conditions associated with this approach prevented quantitation. The results of this study provide new validated standards for the study of 4-(3-pyridyl)-4-oxobutylation of DNA, a critical reaction in the carcinogenesis by 1 and 2, and demonstrate the presence of previously unidentified 2'-deoxycytidine adducts in this DNA.
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Affiliation(s)
- Anna K. Michel
- Masonic
Cancer Center, University of Minnesota, 2231 6th Street SE, Room 2-148 CCRB, Minneapolis, Minnesota 55455, United States
| | - Adam T. Zarth
- Masonic
Cancer Center, University of Minnesota, 2231 6th Street SE, Room 2-148 CCRB, Minneapolis, Minnesota 55455, United States
| | - Pramod Upadhyaya
- Masonic
Cancer Center, University of Minnesota, 2231 6th Street SE, Room 2-148 CCRB, Minneapolis, Minnesota 55455, United States
| | - Stephen S. Hecht
- Masonic
Cancer Center, University of Minnesota, 2231 6th Street SE, Room 2-148 CCRB, Minneapolis, Minnesota 55455, United States
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7
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Liu S, Wang Y. Mass spectrometry for the assessment of the occurrence and biological consequences of DNA adducts. Chem Soc Rev 2015; 44:7829-54. [PMID: 26204249 PMCID: PMC4787602 DOI: 10.1039/c5cs00316d] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Exogenous and endogenous sources of chemical species can react, directly or after metabolic activation, with DNA to yield DNA adducts. If not repaired, DNA adducts may compromise cellular functions by blocking DNA replication and/or inducing mutations. Unambiguous identification of the structures and accurate measurements of the levels of DNA adducts in cellular and tissue DNA constitute the first and important step towards understanding the biological consequences of these adducts. The advances in mass spectrometry (MS) instrumentation in the past 2-3 decades have rendered MS an important tool for structure elucidation, quantification, and revelation of the biological consequences of DNA adducts. In this review, we summarized the development of MS techniques on these fronts for DNA adduct analysis. We placed our emphasis of discussion on sample preparation, the combination of MS with gas chromatography- or liquid chromatography (LC)-based separation techniques for the quantitative measurement of DNA adducts, and the use of LC-MS along with molecular biology tools for understanding the human health consequences of DNA adducts. The applications of mass spectrometry-based DNA adduct analysis for predicting the therapeutic outcome of anti-cancer agents, for monitoring the human exposure to endogenous and environmental genotoxic agents, and for DNA repair studies were also discussed.
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Affiliation(s)
- Shuo Liu
- Environmental Toxicology Graduate Program, University of California, Riverside, California, USA
| | - Yinsheng Wang
- Environmental Toxicology Graduate Program, University of California, Riverside, California, USA and Department of Chemistry, University of California, Riverside, CA 92521-0403, USA.
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8
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Kanaly RA, Micheletto R, Matsuda T, Utsuno Y, Ozeki Y, Hamamura N. Application of DNA adductomics to soil bacterium Sphingobium sp. strain KK22. Microbiologyopen 2015; 4:841-56. [PMID: 26305056 PMCID: PMC4618615 DOI: 10.1002/mbo3.283] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 07/16/2015] [Accepted: 07/21/2015] [Indexed: 12/21/2022] Open
Abstract
Toward the development of ecotoxicology methods to investigate microbial markers of impacts of hydrocarbon processing activities, DNA adductomic analyses were conducted on a sphingomonad soil bacterium. From growing cells that were exposed or unexposed to acrolein, a commonly used biocide in hydraulic fracturing processes, DNA was extracted, digested to 2'-deoxynucleosides and analyzed by liquid chromatography-positive ionization electrospray-tandem mass spectrometry in selected reaction monitoring mode transmitting the [M + H](+) > [M + H - 116](+) transition over 100 transitions. Overall data shown as DNA adductome maps revealed numerous putative DNA adducts under both conditions with some occurring specifically for each condition. Adductomic analyses of triplicate samples indicated that elevated levels of some targeted putative adducts occurred in exposed cells. Two exposure-specific adducts were identified in exposed cells as 3-(2'-deoxyribosyl)-5,6,7,8-tetrahydro-6-hydroxy-(and 8-hydroxy-)pyrimido[1,2-a]- purine-(3H)-one (6- and 8-hydroxy-PdG) following synthesis of authentic standards of these compounds and subsequent analyses. A time course experiment showed that 6- and 8-hydroxy-PdG were detected in bacterial DNA within 30 min of acrolein exposure but were not detected in unexposed cells. This work demonstrated the first application of DNA adductomics to examine DNA damage in a bacterium and sets a foundation for future work.
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Affiliation(s)
- Robert A Kanaly
- Department of Life and Environmental System Science, Graduate School of Nanobiosciences, Yokohama City University, Kanagawa, Yokohama, 236-0027, Japan
| | - Ruggero Micheletto
- Department of Nanosystem Science, Graduate School of Nanobiosciences, Yokohama City University, Kanagawa, Yokohama, 236-0027, Japan
| | - Tomonari Matsuda
- Research Center for Environmental Quality Management, Kyoto University, Otsu, Shiga, 520-0811, Japan
| | - Youko Utsuno
- Department of Life and Environmental System Science, Graduate School of Nanobiosciences, Yokohama City University, Kanagawa, Yokohama, 236-0027, Japan
| | - Yasuhiro Ozeki
- Department of Life and Environmental System Science, Graduate School of Nanobiosciences, Yokohama City University, Kanagawa, Yokohama, 236-0027, Japan
| | - Natsuko Hamamura
- Center for Marine Environmental Studies, Ehime University, Matsuyama, 790-8577, Japan.,Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, 812-8581, Japan
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9
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Zhang F, Bartels MJ, LeBaron MJ, Schisler MR, Gollapudi BB, Moore NP. A novel approach for concurrent quantitation of glutathione, glutathione disulfide, and 2-hydroxyethylated glutathione in lungs of mice exposed to ethylene oxide, using liquid chromatography-positive electrospray tandem mass spectrometry. Biomed Chromatogr 2015; 29:1364-74. [DOI: 10.1002/bmc.3432] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 12/14/2014] [Accepted: 12/29/2014] [Indexed: 11/06/2022]
Affiliation(s)
- Fagen Zhang
- Toxicology and Environmental Research & Consulting; The Dow Chemical Company; 1803 Building Midland MI 48674 USA
| | - Michael J. Bartels
- Toxicology and Environmental Research & Consulting; The Dow Chemical Company; 1803 Building Midland MI 48674 USA
| | - Matthew J. LeBaron
- Toxicology and Environmental Research & Consulting; The Dow Chemical Company; 1803 Building Midland MI 48674 USA
| | - Melissa R. Schisler
- Toxicology and Environmental Research & Consulting; The Dow Chemical Company; 1803 Building Midland MI 48674 USA
| | - B. Bhaskar Gollapudi
- Toxicology and Environmental Research & Consulting; The Dow Chemical Company; 1803 Building Midland MI 48674 USA
| | - Nigel P. Moore
- Toxicology and Environmental Research & Consulting; Dow Europe GmbH; Horgen Switzerland
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10
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Zhang F, Bartels MJ, LeBaron MJ, Schisler MR, Jeong YC, Gollapudi BB, Moore NP. LC–MS/MS simultaneous quantitation of 2-hydroxyethylated, oxidative, and unmodified DNA nucleosides in DNA isolated from tissues of mice after exposure to ethylene oxide. J Chromatogr B Analyt Technol Biomed Life Sci 2015; 976-977:33-48. [DOI: 10.1016/j.jchromb.2014.10.042] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Revised: 10/21/2014] [Accepted: 10/29/2014] [Indexed: 11/28/2022]
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11
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Gavina JMA, Yao C, Feng YL. Recent developments in DNA adduct analysis by mass spectrometry: a tool for exposure biomonitoring and identification of hazard for environmental pollutants. Talanta 2014; 130:475-94. [PMID: 25159438 DOI: 10.1016/j.talanta.2014.06.050] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 06/19/2014] [Accepted: 06/22/2014] [Indexed: 02/08/2023]
Abstract
DNA adducts represent an important category of biomarkers for detection and exposure surveillance of potential carcinogenic and genotoxic chemicals in the environment. Sensitive and specific analytical methods are required to detect and differentiate low levels of adducts from native DNA from in vivo exposure. In addition to biomonitoring of environmental pollutants, analytical methods have been developed for structural identification of adducts which provides fundamental information for determining the toxic pathway of hazardous chemicals. In order to achieve the required sensitivity, mass spectrometry has been increasingly utilized to quantify adducts at low levels as well as to obtain structural information. Furthermore, separation techniques such as chromatography and capillary electrophoresis can be coupled to mass spectrometry to increase the selectivity. This review will provide an overview of advances in detection of adducted and modified DNA by mass spectrometry with a focus on the analysis of nucleosides since 2007. Instrument advances, sample and instrument considerations, and recent applications will be summarized in the context of hazard assessment. Finally, advances in biomonitoring applying mass spectrometry will be highlighted. Most importantly, the usefulness of DNA adducts measurement and detection will be comprehensively discussed as a tool for assessment of in vitro and in vivo exposure to environmental pollutants.
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Affiliation(s)
- Jennilee M A Gavina
- Exposure and Biomonitoring Division, Environmental Health Science and Research Bureau, Environmental and Radiation Health Sciences Directorate, Healthy Environments and Consumer Safety Branch, Health Canada, 50 Columbine Driveway, AL: 0800C, Ottawa, Ontario, Canada K1A 0K9
| | - Chunhe Yao
- Exposure and Biomonitoring Division, Environmental Health Science and Research Bureau, Environmental and Radiation Health Sciences Directorate, Healthy Environments and Consumer Safety Branch, Health Canada, 50 Columbine Driveway, AL: 0800C, Ottawa, Ontario, Canada K1A 0K9
| | - Yong-Lai Feng
- Exposure and Biomonitoring Division, Environmental Health Science and Research Bureau, Environmental and Radiation Health Sciences Directorate, Healthy Environments and Consumer Safety Branch, Health Canada, 50 Columbine Driveway, AL: 0800C, Ottawa, Ontario, Canada K1A 0K9.
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12
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Affiliation(s)
- Natalia Tretyakova
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA.
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13
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XIE YP, TIAN J, GAO P, XU GUOW, FEI X, WANG Y. Determination of Nucleosides in Escherichia coli by Rapid Resolution Liquid Chromatography–Tandem Quadrupole Mass Spectrometry. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2013. [DOI: 10.1016/s1872-2040(13)60622-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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14
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Tretyakova N, Goggin M, Sangaraju D, Janis G. Quantitation of DNA adducts by stable isotope dilution mass spectrometry. Chem Res Toxicol 2012; 25:2007-35. [PMID: 22827593 DOI: 10.1021/tx3002548] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Exposure to endogenous and exogenous chemicals can lead to the formation of structurally modified DNA bases (DNA adducts). If not repaired, these nucleobase lesions can cause polymerase errors during DNA replication, leading to heritable mutations and potentially contributing to the development of cancer. Because of their critical role in cancer initiation, DNA adducts represent mechanism-based biomarkers of carcinogen exposure, and their quantitation is particularly useful for cancer risk assessment. DNA adducts are also valuable in mechanistic studies linking tumorigenic effects of environmental and industrial carcinogens to specific electrophilic species generated from their metabolism. While multiple experimental methodologies have been developed for DNA adduct analysis in biological samples, including immunoassay, HPLC, and ³²P-postlabeling, isotope dilution high performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS) generally has superior selectivity, sensitivity, accuracy, and reproducibility. As typical DNA adduct concentrations in biological samples are between 0.01-10 adducts per 10⁸ normal nucleotides, ultrasensitive HPLC-ESI-MS/MS methodologies are required for their analysis. Recent developments in analytical separations and biological mass spectrometry, especially nanoflow HPLC, nanospray ionization MS, chip-MS, and high resolution MS, have pushed the limits of analytical HPLC-ESI-MS/MS methodologies for DNA adducts, allowing researchers to accurately measure their concentrations in biological samples from patients treated with DNA alkylating drugs and in populations exposed to carcinogens from urban air, drinking water, cooked food, alcohol, and cigarette smoke.
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Affiliation(s)
- Natalia Tretyakova
- Department of Medicinal Chemistry and Masonic Cancer Center, University of Minnesota , Minneapolis, Minnesota 55455, USA.
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15
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Abstract
The detection and characterisation of DNA adducts can provide mechanistic information on mode of action for genotoxic chemicals and in this context is vital for human risk assessments. Adducts are measured extensively in biomonitoring studies to examine exposure to environmental, dietary, and occupational chemicals and as biomarkers of efficacy for cancer chemotherapeutic drugs and chemopreventive agents. Methods used for adduct analysis must possess a certain degree of specificity and be sufficiently sensitive to detect lesions in the model system under investigation. A variety of techniques have been established for this purpose, which are capable of detecting and quantifying adducts in DNA isolated from animal or human tissues, cells, and biofluids as well as naked DNA from in vitro studies. These can be grouped as those involving (32)P-post-labelling, mass spectrometry, physical detection methods, immunological assays and radiolabelled compounds. Each approach presents different advantages and limitations and the most appropriate method depends on the type of sample, level of damage, and nature of the investigation as well as practical considerations. In this chapter, the basic principles of the most commonly used quantitative methods are described and their strengths and weaknesses discussed.
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Affiliation(s)
- Karen Brown
- Department of Cancer Studies and Molecular Medicine, University of Leicester, Leicester, UK.
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16
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Wu KY, Chiang SY, Shih WC, Huang CCJ, Chen MF, Swenberg JA. The application of mass spectrometry in molecular dosimetry: ethylene oxide as an example. MASS SPECTROMETRY REVIEWS 2011; 30:733-756. [PMID: 21328599 DOI: 10.1002/mas.20299] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Mass spectrometry plays an increasingly important role in the search for and quantification of novel chemically specific biomarkers. The revolutionary advances in mass spectrometry instrumentation and technology empower scientists to specifically analyze DNA and protein adducts, considered as molecular dosimeters, derived from reactions of a carcinogen or its active metabolites with DNA or protein. Analysis of the adducted DNA bases and proteins can elucidate the chemically reactive species of carcinogens in humans and can serve as risk-associated biomarkers for early prediction of cancer risk. In this article, we review and compare the specificity, sensitivity, resolution, and ease-of-use of mass spectrometry methods developed to analyze ethylene oxide (EO)-induced DNA and protein adducts, particularly N7-(2-hydroxyethyl)guanine (N7-HEG) and N-(2-hydroxyethyl)valine (HEV), in human samples and in animal tissues. GC/ECNCI-MS analysis after HPLC cleanup is the most sensitive method for quantification of N7-HEG, but limited by the tedious sample preparation procedures. Excellent sensitivity and specificity in analysis of N7-HEG can be achieved by LC/MS/MS analysis if the mobile phase, the inlet (split or splitless), and the collision energy are properly optimized. GC/ECNCI-HRMS and GC/ECNCI-MS/MS analysis of HEV achieves the best performance as compared with GC/ECNCI-MS and GC/EI-MS. In conclusion, future improvements in high-throughput capabilities, detection sensitivity, and resolution of mass spectrometry will attract more scientists to identify and/or quantify novel molecular dosimeters or profiles of these biomarkers in toxicological and/or epidemiological studies.
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Affiliation(s)
- Kuen-Yuh Wu
- Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, Taipei, Taiwan.
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Tompkins EM, McLuckie KIE, Jones DJL, Farmer PB, Brown K. Mutagenicity of DNA adducts derived from ethylene oxide exposure in the pSP189 shuttle vector replicated in human Ad293 cells. Mutat Res 2009; 678:129-37. [PMID: 19477295 DOI: 10.1016/j.mrgentox.2009.05.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2009] [Accepted: 05/19/2009] [Indexed: 12/26/2022]
Abstract
Ethylene oxide (EO) is a widely used chemical intermediate also formed endogenously from ethylene metabolism. Despite conflicting epidemiological evidence, EO is classified by the IARC as a human carcinogen. The mutagenicity and carcinogenicity of EO is attributed to direct reaction with DNA and formation of multiple 2-hydroxyethyl (HE) DNA adducts. However, the actual lesions responsible for the reported mutagenicity of EO have not been established. This study used the supF mutation assay to investigate the biological relevance of low levels of EO-induced DNA adducts in human Ad293 cells, with respect to the type and level of each HE adduct present. Initial experiments were conducted using pSP189 plasmid containing up to 290 N7-HEGuanine (N7-HEG) adducts/10(6) nucleotides, which far exceeds that typically detected in human DNA. No other HE-lesions were detectable using our validated LC-MS/MS assay. Replication in cells failed to produce a statistically significant increase in relative mutation frequency, above background rates in the solvent control. Furthermore, the mutation spectrum compiled for EO-treated plasmid (10-2000muM) did not differ significantly from the spontaneous distribution, suggesting EO is not strongly mutagenic in this system. Under refined reaction conditions using higher EO concentrations capable of inducing detectable levels of N1-HEdA, O(6)-HEdG and N3-HEdU along with N7-HEG, there was a significant dose-related increase in relative mutation frequency above background (3.76- and 5.30-fold at 10 and 30mM, respectively). EO treatment appeared associated with an elevated frequency of GC-->CG mutations and the occurrence of substitutions at AT base pairs. Additionally, there was a distinct GC-->TA mutational hotspot in the 10mM EO spectrum. Overall, the results suggest a certain level of promutagenic adducts must be attained before mutations become detectable above background, indicating that N7-HEG is not a promutagenic lesion, and support a role for the minor products of DNA hydroxyethylation in the generation of base substitutions by EO.
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Affiliation(s)
- Elaine M Tompkins
- Department of Cancer Studies and Molecular Medicine, University of Leicester, Leicester, LE2 7LX, UK
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The formation and biological significance of N7-guanine adducts. Mutat Res 2009; 678:76-94. [PMID: 19465146 DOI: 10.1016/j.mrgentox.2009.05.006] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Accepted: 05/13/2009] [Indexed: 11/24/2022]
Abstract
DNA alkylation or adduct formation occurs at nucleophilic sites in DNA, mainly the N7-position of guanine. Ever since identification of the first N7-guanine adduct, several hundred studies on DNA adducts have been reported. Major issues addressed include the relationships between N7-guanine adducts and exposure, mutagenesis, and other biological endpoints. It became quickly apparent that N7-guanine adducts are frequently formed, but may have minimal biological relevance, since they are chemically unstable and do not participate in Watson Crick base pairing. However, N7-guanine adducts have been shown to be excellent biomarkers for internal exposure to direct acting and metabolically activated carcinogens. Questions arise, however, regarding the biological significance of N7-guanine adducts that are readily formed, do not persist, and are not likely to be mutagenic. Thus, we set out to review the current literature to evaluate their formation and the mechanistic evidence for the involvement of N7-guanine adducts in mutagenesis or other biological processes. It was concluded that there is insufficient evidence that N7-guanine adducts can be used beyond confirmation of exposure to the target tissue and demonstration of the molecular dose. There is little to no evidence that N7-guanine adducts or their depurination product, apurinic sites, are the cause of mutations in cells and tissues, since increases in AP sites have not been shown unless toxicity is extant. However, more research is needed to define the extent of chemical depurination versus removal by DNA repair proteins. Interestingly, N7-guanine adducts are clearly present as endogenous background adducts and the endogenous background amounts appear to increase with age. Furthermore, the N7-guanine adducts have been shown to convert to ring opened lesions (FAPy), which are much more persistent and have higher mutagenic potency. Studies in humans are limited in sample size and differences between controls and study groups are small. Future investigations should involve human studies with larger numbers of individuals and analysis should include the corresponding ring opened FAPy derivatives.
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