1
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Colas S, Marie B, Milhe-Poutingon M, Lot MC, Boullemant A, Fortin C, Le Faucheur S. Meta-metabolomic responses of river biofilms to cobalt exposure and use of dose-response model trends as an indicator of effects. JOURNAL OF HAZARDOUS MATERIALS 2024; 470:134099. [PMID: 38547754 DOI: 10.1016/j.jhazmat.2024.134099] [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: 11/14/2023] [Revised: 03/18/2024] [Accepted: 03/19/2024] [Indexed: 04/25/2024]
Abstract
The response of the meta-metabolome is rarely used to characterize the effects of contaminants on a whole community. Here, the meta-metabolomic fingerprints of biofilms were examined after 1, 3 and 7 days of exposure to five concentrations of cobalt (from background concentration to 1 × 10-5 M) in aquatic microcosms. The untargeted metabolomic data were processed using the DRomics tool to build dose-response models and to calculate benchmark-doses. This approach made it possible to use 100% of the chemical signal instead of being limited to the very few annotated metabolites (7%). These benchmark-doses were further aggregated into an empirical cumulative density function. A trend analysis of the untargeted meta-metabolomic feature dose-response curves after 7 days of exposure suggested the presence of a concentration range inducing defense responses between 1.7 × 10-9 and 2.7 × 10-6 M, and of a concentration range inducing damage responses from 2.7 × 10-6 M and above. This distinction was in good agreement with changes in the other biological parameters studied (biomass and chlorophyll content). This study demonstrated that the molecular defense and damage responses can be related to contaminant concentrations and represents a promising approach for environmental risk assessment of metals.
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Affiliation(s)
- Simon Colas
- Universite de Pau et des Pays de l'Adour, E2S-UPPA, CNRS, IPREM, Pau, France.
| | - Benjamin Marie
- UMR 7245 CNRS/MNHN " Molécules de Communication et Adaptations des Micro-organismes ", Muséum National d'Histoire Naturelle, Paris, France
| | | | | | | | - Claude Fortin
- Institut National de la Recherche Scientifique - Eau Terre Environnement, Québec, Canada
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2
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Wang F, Ye L, Jiang X, Zhang R, Chen S, Chen L, Yu H, Zeng X, Li D, Xing X, Xiao Y, Chen W. Specific CpG sites methylation is associated with hematotoxicity in low-dose benzene-exposed workers. ENVIRONMENT INTERNATIONAL 2024; 186:108645. [PMID: 38615541 DOI: 10.1016/j.envint.2024.108645] [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: 01/14/2024] [Revised: 03/10/2024] [Accepted: 04/08/2024] [Indexed: 04/16/2024]
Abstract
Benzene is a broadly used industrial chemicals which causes various hematologic abnormalities in human. Altered DNA methylation has been proposed as epigenetic biomarkers in health risk evaluation of benzene exposure, yet the role of methylation at specific CpG sites in predicting hematological effects remains unclear. In this study, we recruited 120 low-level benzene-exposed and 101 control male workers from a petrochemical factory in Maoming City, Guangdong Province, China. Urinary S-phenylmercapturic acid (SPMA) in benzene-exposed workers was 3.40-fold higher than that in control workers (P < 0.001). Benzene-induced hematotoxicity was characterized by reduced white blood cells counts and nuclear division index (NDI), along with an increased DNA damage and urinary 8-hydroxy-2'-deoxyguanosine (all P < 0.05). Methylation levels of TRIM36, MGMT and RASSF1a genes in peripheral blood lymphocytes (PBLCs) were quantified by pyrosequencing. CpG site 6 of TRIM36, CpG site 2, 4, 6 of RASSF1a and CpG site 1, 3 of MGMT methylation were recognized as hot CpG sites due to a strong correlation with both internal exposure and hematological effects. Notably, integrating hot CpG sites methylation of multiple genes reveal a higher efficiency in prediction of integrative damage compared to individual genes at hot CpG sites. The negative dose-response relationship between the combined methylation of hot CpG sites in three genes and integrative damage enabled the classification of benzene-exposed individuals into high-risk or low-risk groups using the median cut-off value of the integrative index. Subsequently, a prediction model for integrative damage in benzene-exposed populations was built based on the methylation status of the identified hot CpG sites in the three genes. Taken together, these findings provide a novel insight into application prospect of specific CpG site methylation as epi-biomarkers for health risk assessment of environmental pollutants.
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Affiliation(s)
- Feier Wang
- Department of Toxicology, Guangdong Provincial Key Laboratory of Food, Nutrition and Health, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Lizhu Ye
- Department of Toxicology, Guangdong Provincial Key Laboratory of Food, Nutrition and Health, School of Public Health, Sun Yat-sen University, Guangzhou, China; Boji Drug Evaluation Center, Boji Medical Technology Co., Ltd, Guangzhou, China
| | - Xinhang Jiang
- Department of Toxicology, Guangdong Provincial Key Laboratory of Food, Nutrition and Health, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Rui Zhang
- Department of Toxicology, Guangdong Provincial Key Laboratory of Food, Nutrition and Health, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Shen Chen
- Department of Toxicology, Guangdong Provincial Key Laboratory of Food, Nutrition and Health, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Liping Chen
- Department of Toxicology, Guangdong Provincial Key Laboratory of Food, Nutrition and Health, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Hongyao Yu
- Department of Toxicology, Guangdong Provincial Key Laboratory of Food, Nutrition and Health, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Xiaowen Zeng
- Department of Toxicology, Guangdong Provincial Key Laboratory of Food, Nutrition and Health, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Daochuan Li
- Department of Toxicology, Guangdong Provincial Key Laboratory of Food, Nutrition and Health, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Xiumei Xing
- Department of Toxicology, Guangdong Provincial Key Laboratory of Food, Nutrition and Health, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Yongmei Xiao
- Department of Toxicology, Guangdong Provincial Key Laboratory of Food, Nutrition and Health, School of Public Health, Sun Yat-sen University, Guangzhou, China.
| | - Wen Chen
- Department of Toxicology, Guangdong Provincial Key Laboratory of Food, Nutrition and Health, School of Public Health, Sun Yat-sen University, Guangzhou, China.
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3
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Colas S, Le Faucheur S. How do biomarkers dance? Specific moves of defense and damage biomarkers for biological interpretation of dose-response model trends. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133180. [PMID: 38104522 DOI: 10.1016/j.jhazmat.2023.133180] [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: 08/05/2023] [Revised: 11/13/2023] [Accepted: 12/03/2023] [Indexed: 12/19/2023]
Abstract
Omics studies are currently increasingly used in ecotoxicology to highlight the induction of known or novel biomarkers when organisms are exposed to contaminants. Although it is virtually impossible to identify all biomarkers from all organisms, biomarkers can be grouped as defense or damage biomarkers, exhibiting a limited number of response trends. Our working hypothesis is that defense and damage biomarkers follow different dose-response patterns. A meta-analysis of 156 articles and 2595 observations of dose-response curves of defense and damage biomarkers was carried out in order to characterize the response trends of these biological parameters in a large panel of living organisms (18 phyla) exposed to inorganic or organic contaminants (176 in total). Using multinomial logistic regression models, defense biomarkers were found to describe biphasic responses (bell- and U-shaped) to a greater extent (2.5 times) than damage biomarkers. In contrast, damage biomarkers varied mainly monotonically (decreasing or increasing), representing 85% of the observations. Neither the nature of the contaminant nor the type of organisms belonging to 4 kingdoms, influence these specific responses. This result suggests that cellular defense and damage mechanisms are not specific to stressors and are conserved throughout life. Trend analysis of dose-response models as a biological interpretation of biomarkers could thus be a valuable way to exploit large omics datasets.
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Affiliation(s)
- Simon Colas
- Universite de Pau et des Pays de l'Adour, E2S-UPPA, CNRS, IPREM, Pau, France.
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4
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Xu L, Li Y, Ma W, Sun X, Fan R, Jin Y, Chen N, Zhu X, Guo H, Zhao K, Luo J, Li C, Zheng Y, Yu D. Diesel exhaust particles exposure induces liver dysfunction: Exploring predictive potential of human circulating microRNAs signature relevant to liver injury risk. JOURNAL OF HAZARDOUS MATERIALS 2023; 458:132060. [PMID: 37454487 DOI: 10.1016/j.jhazmat.2023.132060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 06/30/2023] [Accepted: 07/12/2023] [Indexed: 07/18/2023]
Abstract
Diesel exhaust particles (DEP) pollution should be taken seriously because it is an extensive environmental and occupational health concern. Exploring early effect biomarkers is crucial for monitoring and managing DEP-associated health risk assessment. Here, we found that serum levels of 67 miRNAs were dysregulated in DEP exposure group. Notably, 20 miRNAs were identified as each having a significant dose-response relationship with the internal exposure level of DEP. Further, we revealed that the DEP exposure could affect the liver function of subjects and that 7 miRNAs (including the well-known liver injury indicator, miR-122-5p) could serve as the novel epigenetic-biomarkers (epi-biomarkers) to reflect the liver-specific response to the DEP exposure. Importantly, an unprecedented prediction model using these 7 miRNAs was established for the assessment of DEP-induced liver injury risk. Finally, bioinformatic analysis indicated that the unique set of miRNA panel in serum might also contribute to the molecular mechanism of DEP exposure-induced liver damage. These results broaden our understanding of the adverse health outcomes of DEP exposure. Noteworthy, we believe this study could shed light on roles and functions of epigenetic biomarkers from environmental exposure to health outcomes by revealing the full chain of exposure-miRNAs-molecular pathways-disease evidence.
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Affiliation(s)
- Lin Xu
- School of Public Health, Qingdao University, Qingdao, China
| | - Yanting Li
- School of Public Health, Qingdao University, Qingdao, China
| | - Wanli Ma
- School of Public Health, Qingdao University, Qingdao, China
| | - Xueying Sun
- School of Public Health, Qingdao University, Qingdao, China
| | - Rongrong Fan
- School of Public Health, Qingdao University, Qingdao, China
| | - Yuan Jin
- School of Public Health, Qingdao University, Qingdao, China
| | - Ningning Chen
- School of Public Health, Qingdao University, Qingdao, China
| | - Xiaoxiao Zhu
- School of Public Health, Qingdao University, Qingdao, China
| | - Huan Guo
- School of Public Health, Huazhong University of Science and Technology, Wuhan, China
| | - Kunming Zhao
- School of Public Health, Qingdao University, Qingdao, China
| | - Jiao Luo
- School of Public Health, Qingdao University, Qingdao, China
| | - Chuanhai Li
- School of Public Health, Qingdao University, Qingdao, China
| | - Yuxin Zheng
- School of Public Health, Qingdao University, Qingdao, China
| | - Dianke Yu
- School of Public Health, Qingdao University, Qingdao, China.
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5
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Conolly RP, Clewell HJ, Moore MM, Campbell JL, Cheng W, Gentry RR. PBPK modeling to evaluate maximum tolerated doses: A case study with 3-chloroallyl alcohol. Front Pharmacol 2023; 14:1088011. [PMID: 36909196 PMCID: PMC9992188 DOI: 10.3389/fphar.2023.1088011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 02/09/2023] [Indexed: 02/25/2023] Open
Abstract
Introduction: A physiologically based pharmacokinetic (PBPK) model for 3-chloroallyl alcohol (3-CAA) was developed and used to evaluate the design of assays for the in vivo genotoxicity of 3-CAA. Methods: Model development was supported by read across from a published PBPK model for ethanol. Read across was motivated by the expectation that 3-CAA, which like ethanol is a primary alcohol, is metabolized largely by hepatic alcohol dehydrogenases. The PBPK model was used to evaluate how two metrics of tissue dosimetry, maximum blood concentration (Cmax; mg/L) and area under the curve (AUC; mg-hr/L) vary with dose of 3-CAA and with dose route (oral gavage, drinking water). Results: The model predicted that oral gavage results in a 6-fold higher Cmax than the same dose administered in drinking water, but in similar AUCs. Predicted Cmax provided the best correlation with severe toxicity (e.g., lethality) from 3-CAA, consistent with the production of a reactive metabolite. Therefore, drinking water administration can achieve higher sustained concentration without severe toxicity in vivo. Discussion: This evaluation is significant because cytotoxicity is a potential confounder of mutagenicity testing. The PBPK model can be used to ensure that studies meet OECD and USEPA test guidelines and that the highest dose used is not associated with severe toxicity. In addition, PBPK modeling provides assurance of target tissue (e.g., bone marrow) exposure even in the absence of laboratory data, by defining the relationship between applied dose and target tissue dose based on accepted principles of pharmacokinetics, relevant physiology and biochemistry of the dosed animals, and chemical-specific information.
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6
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Ye L, He Z, Li D, Chen L, Chen S, Guo P, Yu D, Ma L, Niu Y, Duan H, Xing X, Xiao Y, Zeng X, Wang Q, Dong G, Aschner M, Zheng Y, Chen W. CpG site-specific methylation as epi-biomarkers for the prediction of health risk in PAHs-exposed populations. JOURNAL OF HAZARDOUS MATERIALS 2022; 431:128538. [PMID: 35231813 DOI: 10.1016/j.jhazmat.2022.128538] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 02/03/2022] [Accepted: 02/19/2022] [Indexed: 06/14/2023]
Abstract
Environmental insults can lead to alteration in DNA methylation of specific genes. To address the role of altered DNA methylation in prediction of polycyclic aromatic hydrocarbons (PAHs) exposure-induced genetic damage, we recruited two populations, including diesel engine exhausts (low-level) and coke oven emissions (high-level) exposed subjects. The positive correlation was observed between the internal exposure marker (1-hydroxypyrene) and the extents of DNA damage (P < 0.05). The methylation of representative genes, including TRIM36, RASSF1a, and MGMT in peripheral blood lymphocytes was quantitatively examined by bisulfite-pyrosequencing assay. The DNA methylation of these three genes in response to PAHs exposure were changed in a CpG-site-specific manner. The identified hot CpG site-specific methylation of three genes exhibited higher predictive power for DNA damage than the respective single genes in both populations. Furthermore, the dose-response relationship analysis revealed a nonlinear U-shape curve of TRIM36 or RASSF1a methylation in combined population, which led to determination of the threshold of health risk. Furthermore, we established a prediction model for genetic damage based on the unidirectional-alteration MGMT methylation levels. In conclusion, this study provides new insight into the application of multiple epi-biomarkers for health risk assessment upon PAHs exposure.
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Affiliation(s)
- Lizhu Ye
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Zhini He
- Food Safety and Health Research Center, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 510515, China
| | - Daochuan Li
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Liping Chen
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Shen Chen
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Ping Guo
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Dianke Yu
- Department of Toxicology, School of Public Health, Qingdao University, Qingdao 266021, China
| | - Lu Ma
- Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Department of Toxicology, School of Public Health, Guizhou Medical University, Guiyang 550025, China
| | - Yong Niu
- Key Laboratory of Chemical Safety and Health, National Institute for Occupational Health and Poison Control, Chinese Center for Disease Control and Prevention, Beijing 100050, China
| | - Huawei Duan
- Key Laboratory of Chemical Safety and Health, National Institute for Occupational Health and Poison Control, Chinese Center for Disease Control and Prevention, Beijing 100050, China
| | - Xiumei Xing
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Yongmei Xiao
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Xiaowen Zeng
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Qing Wang
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Guanghui Dong
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Forchheimer 209, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Yuxin Zheng
- Department of Toxicology, School of Public Health, Qingdao University, Qingdao 266021, China.
| | - Wen Chen
- Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China.
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7
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Spencer PS, Kisby GE. Role of Hydrazine-Related Chemicals in Cancer and Neurodegenerative Disease. Chem Res Toxicol 2021; 34:1953-1969. [PMID: 34379394 DOI: 10.1021/acs.chemrestox.1c00150] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Hydrazine-related chemicals (HRCs) with carcinogenic and neurotoxic potential are found in certain mushrooms and plants used for food and in products employed in various industries, including aerospace. Their propensity to induce DNA damage (mostly O6-, N7- and 8-oxo-guanine lesions) resulting in multiple downstream effects is linked with both cancer and neurological disease. For cycling cells, unrepaired DNA damage leads to mutation and uncontrolled mitosis. By contrast, postmitotic neurons attempt to re-enter the cell cycle but undergo apoptosis or nonapoptotic cell death. Biomarkers of exposure to HRCs can be used to explore whether these substances are risk factors for sporadic amyotrophic laterals sclerosis and other noninherited neurodegenerative diseases, which is the focus of this paper.
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Affiliation(s)
- Peter S Spencer
- Oregon Health and Science University, Portland, Oregon 97239, United States
| | - Glen E Kisby
- College of Osteopathic Medicine of the Pacific Northwest, Western University of Health Sciences, Lebanon, Oregon 97355, United States
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8
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Cohen JM, Beck BD, Rhomberg LR. Historical perspective on the role of cell proliferation in carcinogenesis for DNA-reactive and non-DNA-reactive carcinogens: Arsenic as an example. Toxicology 2021; 456:152783. [PMID: 33872731 DOI: 10.1016/j.tox.2021.152783] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 04/07/2021] [Accepted: 04/11/2021] [Indexed: 10/21/2022]
Abstract
Our understanding of the etiology of cancer has developed significantly over the past fifty years, beginning with a single-hit linear no-threshold (LNT) conceptual model based on early studies conducted in Drosophila. Over the past several decades, multiple lines of evidence have accumulated to support a contemporary model of chemical carcinogenesis: a multi-hit model involving a prolonged stress environment that over time may drive the mutation of multiple cells into an injured state that ultimately could lead to uncontrolled proliferation via clonal expansion of mutation-carrying daughter cells. Arsenic carcinogenicity offers a useful case study for further exploration of advanced conceptual models for chemical carcinogenesis. A threshold for arsenic carcinogenicity is supported by its mode of action, characterized by repeating cycles of cytotoxicity and cellular regeneration. Furthermore, preliminary meta-analyses of epidemiology dose-response data for inorganic arsenic (iAs) and bladder cancer, correlated to dose-response data measured in vitro, support a threshold of effect in humans on the order of 50-100 μg/L in drinking water. In light of recent developments in our understanding of cancer etiology, we urge strong consideration of the existing mode-of-action evidence supporting a threshold of effect for arsenic carcinogenicity, as well as consideration of the potential methodological pitfalls in evaluating epidemiology dose-response data that could potentially bias in the direction of low-dose linearity.
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9
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Ndreu L, Erber LN, Törnqvist M, Tretyakova NY, Karlsson I. Characterizing Adduct Formation of Electrophilic Skin Allergens with Human Serum Albumin and Hemoglobin. Chem Res Toxicol 2020; 33:2623-2636. [PMID: 32875789 PMCID: PMC7582624 DOI: 10.1021/acs.chemrestox.0c00271] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
![]()
Skin
(contact) allergy, the most predominant form of immunotoxicity
in humans, is caused by small electrophilic compounds (haptens) that
modify endogenous proteins. Approximately 20% of the general population
in the Western world is affected by contact allergy. Although the
importance of the hapten–protein conjugates is well established
in the initiation of the immunological reaction, not much progress
has been made regarding identification of these conjugates in vivo or exploration of their potential as diagnostic
tools. In this study, the human serum albumin (HSA) and human hemoglobin
(Hb) adductome for three representative contact allergens with different
chemical properties, 1-chloro-2,4-dinitrobenzene (DNCB), 1,2-epoxy-3-phenoxypropane
(PGE), and 2-bromo-2-(bromomethyl)glutaronitrile (MDBGN), were studied.
Plasma and red blood cell lysate were used as a source for HSA and
Hb, respectively. The Direct Peptide Reactivity Assay was used to
investigate adduct formation of MDBGN with nucleophilic moieties and
revealed that MDGBN is converted to 2-methylenepentanedinitrile in
the presence of sulfhydryl groups prior to adduct formation. Following
incubation of HSA and Hb with haptens, an Orbitrap Q Exactive high-resolution
mass spectrometer was used to perform an initial untargeted analysis
to screen for adduct formation, followed by confirmation by targeted
Parallel Reaction Monitoring analysis. Although a subset of adducted
sites was confirmed by targeted analysis, only some of the adducted
peptides showed an increase in the relative amount of the adducted
peptide with an increased concentration of hapten. In total, seven
adduct sites for HSA and eight for Hb were confirmed for DNCB and
PGE. These sites are believed to be the most reactive. Further, three
of the HSA sites (Cys34, Cys62, and Lys190) and six of the Hb sites (subunit α: Val1, His45, His72; subunit β: Cys93, His97, and Cys112) were haptenated already
at the lowest level of hapten to protein molar ratio (0.1:1), indicating
that these sites are the most likely to be modified in vivo. To the best of our knowledge, this is the first time that the adductome
of Hb has been studied in the context of contact allergens. Identification
of the most reactive sites of abundant proteins, such as HSA and Hb,
is the first step toward identification of contact allergy biomarkers
that can be used for biomonitoring and to develop better diagnostic
tools based on a blood sample.
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Affiliation(s)
- Lorena Ndreu
- Department of Environmental Science, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Luke N Erber
- Department of Medicinal Chemistry and the College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455, United States.,Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Margareta Törnqvist
- Department of Environmental Science, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Natalia Y Tretyakova
- Department of Medicinal Chemistry and the College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455, United States.,Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Isabella Karlsson
- Department of Environmental Science, Stockholm University, SE-106 91 Stockholm, Sweden
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10
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Albertini RJ, Kaden DA. Mutagenicity monitoring in humans: Global versus specific origin of mutations. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2020; 786:108341. [PMID: 33339577 DOI: 10.1016/j.mrrev.2020.108341] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 10/08/2020] [Accepted: 10/14/2020] [Indexed: 01/19/2023]
Abstract
An underappreciated aspect of human mutagenicity biomonitoring is tissue specificity reflected in different assays, especially those that measure events that can only occur in developing bone marrow (BM) cells. Reviewed here are 9 currently-employed human mutagenicity biomonitoring assays. Several assays measure chromosome-level events in circulating T-lymphocytes (T-cells), i.e., traditional analyses of aberrations, translocation studies involving chromosome painting and fluorescence in situ hybridization (FISH) and determinations of micronuclei (MN). Other T-cell assays measure gene mutations. i.e., hypoxanthine-guanine phosphoriboslytransferase (HPRT) and phosphoribosylinositol glycan class A (PIGA). In addition to the T-cell assays, also reviewed are those assays that measure events in peripheral blood cells that necessarily arose in BM cells, i.e., MN in reticulocytes; glycophorin A (GPA) gene mutations in red blood cells (RBCs), and PIGA gene mutations in RBC or granulocytes. This review considers only cell culture- or cytometry-based assays to describe endpoints measured, methods, optimal sampling times, and sample summaries of typical quantitative and qualitative results. However, to achieve its intended focus on the target cells where events occur, kinetics of the cells of peripheral blood that derive at some point from precursor cells are reviewed to identify body sites and tissues where the genotoxic events originate. Kinetics indicate that in normal adults, measured events in T-cells afford global assessments of in vivo mutagenicity but are not specific for BM effects. Therefore, an agent's capacity for inducing mutations in BM cells cannot be reliably inferred from T-cell assays as the magnitude of effect in BM, if any, is unknown. By contrast, chromosome or gene level mutations measured in RBCs/reticulocytes or granulocytes must originate in BM cells, i.e. in RBC or granulocyte precursors, thereby making them specific indicators for effects in BM. Assays of mutations arising directly in BM cells may quantitatively reflect the mutagenicity of potential leukemogenic agents.
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Affiliation(s)
- Richard J Albertini
- University of Vermont, 111 Colchester Avenue, Burlington, VT 05401, United States
| | - Debra A Kaden
- Ramboll US Consulting, Inc., 101 Federal Street, Suite 1900, Boston, MA 02110, United States.
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11
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Abstract
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The cellular outcomes of chemical
exposure are as much about the
cellular response to the chemical as it is an effect of the chemical. We are growing in our understanding
of the genotoxic interaction between chemistry and biology. For example,
recent data has revealed the biological basis for mutation induction
curves for a methylating chemical, which has been shown to be dependent
on the repair capacity of the cells. However, this is just one end
point in the toxicity pathway from chemical exposure to cell death.
Much remains to be known in order for us to predict how cells will
respond to a certain dose. Methylating agents, a subset of alkylating
agents, are of particular interest, because of the variety of adverse
genetic end points that can result, not only at increasing doses,
but also over time. For instance, methylating agents are mutagenic,
their potency, for this end point, is determined by the cellular repair
capacity of an enzyme called methylguanine DNA-methyltransferase (MGMT)
and its ability to repair the induceed methyl adducts. However, methyl
adducts can become clastogenic. Erroneous biological processing will
convert mutagenic adducts to clastogenic events in the form of double
strand breaks (DSBs). How the cell responds to DSBs is via a cascade
of protein kinases, which is called the DNA damage response (DDR),
which will determine if the damage is repaired effectively, via homologous
recombination, or with errors, via nonhomologous end joining, or whether
the cell dies via apoptosis or enters senescence. The fate of cells
may be determined by the extent of damage and the resulting strength
of DDR signaling. Therefore, thresholds of damage may exist that determine
cell fate. Such thresholds would be dependent on each of the repair
and response mechanisms that these methyl adducts stimulate. The molecular
mechanism of how methyl adducts kill cells is still to be fully resolved.
If we are able to quantify each of these thresholds of damage for
a given cell, then we can ascertain, of the many adducts that are
induced, what proportion of them are mutagenic, what proportion are
clastogenic, and how many of these clastogenic events are toxic. This
review examines the possibility of dose and damage thresholds for
methylating agents, from the perspective of the underlying evolutionary
mechanisms that may be accountable.
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Affiliation(s)
- Adam D Thomas
- Centre for Research in Biosciences, University of the West of England, Frenchay Campus, Bristol BS16 1QY, United Kingdom
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12
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Wang J, Zhang G, Lin Z, Luo Y, Fang H, Yang L, Xie J, Guo L. Determination of arsenicals in mouse tissues after simulated exposure to arsenic from rice for sixteen weeks and the effects on histopathological features. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 200:110742. [PMID: 32470681 DOI: 10.1016/j.ecoenv.2020.110742] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 04/21/2020] [Accepted: 04/29/2020] [Indexed: 06/11/2023]
Abstract
The accumulation of arsenic in rice has become a worldwide concern. In this study, dose-dependency in tissues (intestine, liver and kidney) and blood distribution of inorganic arsenicals and their methylated metabolites were investigated in male C57BL/6 mice exposed to four arsenic species (arsenite [iAs]III, arsenate [iAs]V, monomethylarsonate [MMA]V, and dimethylarsinate [DMA]V) at four doses (control [C]: 0 μg/g, simulation [S]: 0.91 μg/g, medium [M]: 9.1 μg/g and high [H]: 30 μg/g) according to the arsenical composition in rice for 8 and 16 weeks. No adverse effects were observed, while body weight gain decreased in group H. Increases in total arsenic concentrations (CtAs) and histopathological changes in the tissues occurred in all of the test groups. CtAs presented a tendency of kidney > intestine > liver > blood and were time-/dose-dependent in the liver and kidney in groups M and H. In the intestine and blood, abundant iAs (23%-28% in blood and 36%-49% in intestine) was detected in groups M and H, and CtAs decreased in group H from the 8th week to the 16th week. PMI decreased in the liver and SMI decreased in the kidney. These results indicate that the three tissues are injured through food arsenic. The intestine can also accumulate food arsenic, and the high arsenic dose will cause a deficiency in the absorbing function of the intestine. Thus, long-term exposure to arsenic-contaminated rice should be taken seriously attention.
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Affiliation(s)
- Jiating Wang
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, 523808, China.
| | - Guiwei Zhang
- Shenzhen Academy of Metrology and Quality Inspection, Shenzhen, 518000, China.
| | - Zeheng Lin
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, 523808, China.
| | - Yu Luo
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, 523808, China.
| | - Heng Fang
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, 523808, China.
| | - Linjie Yang
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, 523808, China.
| | - Jinying Xie
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, 523808, China.
| | - Lianxian Guo
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, 523808, China.
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13
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Walker VE, Fennell TR, Walker DM, Bauer MJ, Upton PB, Douglas GR, Swenberg JA. Analysis of DNA Adducts and Mutagenic Potency and Specificity in Rats Exposed to Acrylonitrile. Chem Res Toxicol 2020; 33:1609-1622. [PMID: 32529823 DOI: 10.1021/acs.chemrestox.0c00153] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Acrylonitrile (ACN), which is a widely used industrial chemical, induces cancers in multiple organs/tissues of rats by unresolved mechanisms. For this report, evidence for ACN-induced direct/indirect DNA damage and mutagenesis was investigated by assessing the ability of ACN, or its reactive metabolite, 2-cyanoethylene oxide (CEO), to bind to DNA in vitro, to form select DNA adducts [N7-(2'-oxoethyl)guanine, N2,3-ethenoguanine, 1,N6-ethenodeoxyadenosine, and 3,N4-ethenodeoxycytidine] in vitro and/or in vivo, and to perturb the frequency and spectra of mutations in the hypoxanthine-guanine phosphoribosyltransferase (Hprt) gene in rats exposed to ACN in drinking water. Adducts and frequencies and spectra of Hprt mutations were analyzed using published methods. Treatment of DNA from human TK6 lymphoblastoid cells with [2,3-14C]-CEO produced dose-dependent binding of 14C-CEO equivalents, and treatment of DNA from control rat brain/liver with CEO induced dose-related formation of N7-(2'-oxoethyl)guanine. No etheno-DNA adducts were detected in target tissues (brain and forestomach) or nontarget tissues (liver and spleen) in rats exposed to 0, 3, 10, 33, 100, or 300 ppm ACN for up to 105 days or to 0 or 500 ppm ACN for ∼15 months; whereas N7-(2'-oxoethyl)guanine was consistently measured at nonsignificant concentrations near the assay detection limit only in liver of animals exposed to 300 or 500 ppm ACN for ≥2 weeks. Significant dose-related increases in Hprt mutant frequencies occurred in T-lymphocytes from spleens of rats exposed to 33-500 ppm ACN for 4 weeks. Comparisons of "mutagenic potency estimates" for control rats versus rats exposed to 500 ppm ACN for 4 weeks to analogous data from rats/mice treated at a similar age with N-ethyl-N-nitrosourea or 1,3-butadiene suggest that ACN has relatively limited mutagenic effects in rats. Considerable overlap between the sites and types of mutations in ACN-exposed rats and butadiene-exposed rats/mice, but not controls, provides evidence that the carcinogenicity of these epoxide-forming chemicals involves corresponding mutagenic mechanisms.
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Affiliation(s)
- Vernon E Walker
- Chemical Industry Institute of Toxicology, Research Triangle Park, North Carolina 27709, United States.,Department of Pathology and Laboratory Medicine, University of Vermont, Burlington, Vermont 05405, United States.,The Burlington HC Research Group, Inc., Jericho, Vermont 05465, United States
| | - Timothy R Fennell
- Chemical Industry Institute of Toxicology, Research Triangle Park, North Carolina 27709, United States.,Center for Bioorganic Chemistry, RTI International, Research Triangle Park, North Carolina 27709, United States
| | - Dale M Walker
- The Burlington HC Research Group, Inc., Jericho, Vermont 05465, United States.,Experimental Pathology Laboratories, Sterling, Virginia 20167, United States
| | | | - Patricia B Upton
- Chemical Industry Institute of Toxicology, Research Triangle Park, North Carolina 27709, United States.,Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - George R Douglas
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario K1A 0K9, Canada
| | - James A Swenberg
- Chemical Industry Institute of Toxicology, Research Triangle Park, North Carolina 27709, United States.,Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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14
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Hartwig A, Arand M, Epe B, Guth S, Jahnke G, Lampen A, Martus HJ, Monien B, Rietjens IMCM, Schmitz-Spanke S, Schriever-Schwemmer G, Steinberg P, Eisenbrand G. Mode of action-based risk assessment of genotoxic carcinogens. Arch Toxicol 2020; 94:1787-1877. [PMID: 32542409 PMCID: PMC7303094 DOI: 10.1007/s00204-020-02733-2] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 03/31/2020] [Indexed: 12/16/2022]
Abstract
The risk assessment of chemical carcinogens is one major task in toxicology. Even though exposure has been mitigated effectively during the last decades, low levels of carcinogenic substances in food and at the workplace are still present and often not completely avoidable. The distinction between genotoxic and non-genotoxic carcinogens has traditionally been regarded as particularly relevant for risk assessment, with the assumption of the existence of no-effect concentrations (threshold levels) in case of the latter group. In contrast, genotoxic carcinogens, their metabolic precursors and DNA reactive metabolites are considered to represent risk factors at all concentrations since even one or a few DNA lesions may in principle result in mutations and, thus, increase tumour risk. Within the current document, an updated risk evaluation for genotoxic carcinogens is proposed, based on mechanistic knowledge regarding the substance (group) under investigation, and taking into account recent improvements in analytical techniques used to quantify DNA lesions and mutations as well as "omics" approaches. Furthermore, wherever possible and appropriate, special attention is given to the integration of background levels of the same or comparable DNA lesions. Within part A, fundamental considerations highlight the terms hazard and risk with respect to DNA reactivity of genotoxic agents, as compared to non-genotoxic agents. Also, current methodologies used in genetic toxicology as well as in dosimetry of exposure are described. Special focus is given on the elucidation of modes of action (MOA) and on the relation between DNA damage and cancer risk. Part B addresses specific examples of genotoxic carcinogens, including those humans are exposed to exogenously and endogenously, such as formaldehyde, acetaldehyde and the corresponding alcohols as well as some alkylating agents, ethylene oxide, and acrylamide, but also examples resulting from exogenous sources like aflatoxin B1, allylalkoxybenzenes, 2-amino-3,8-dimethylimidazo[4,5-f] quinoxaline (MeIQx), benzo[a]pyrene and pyrrolizidine alkaloids. Additionally, special attention is given to some carcinogenic metal compounds, which are considered indirect genotoxins, by accelerating mutagenicity via interactions with the cellular response to DNA damage even at low exposure conditions. Part C finally encompasses conclusions and perspectives, suggesting a refined strategy for the assessment of the carcinogenic risk associated with an exposure to genotoxic compounds and addressing research needs.
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Affiliation(s)
- Andrea Hartwig
- Department of Food Chemistry and Toxicology, Institute of Applied Biosciences (IAB), Karlsruhe Institute of Technology (KIT), Adenauerring 20a, 76131, Karlsruhe, Germany.
| | - Michael Arand
- Institute of Pharmacology and Toxicology, University of Zurich, 8057, Zurich, Switzerland
| | - Bernd Epe
- Institute of Pharmacy and Biochemistry, University of Mainz, 55099, Mainz, Germany
| | - Sabine Guth
- Department of Toxicology, IfADo-Leibniz Research Centre for Working Environment and Human Factors, TU Dortmund, Ardeystr. 67, 44139, Dortmund, Germany
| | - Gunnar Jahnke
- Department of Food Chemistry and Toxicology, Institute of Applied Biosciences (IAB), Karlsruhe Institute of Technology (KIT), Adenauerring 20a, 76131, Karlsruhe, Germany
| | - Alfonso Lampen
- Department of Food Safety, German Federal Institute for Risk Assessment (BfR), 10589, Berlin, Germany
| | - Hans-Jörg Martus
- Novartis Institutes for BioMedical Research, 4002, Basel, Switzerland
| | - Bernhard Monien
- Department of Food Safety, German Federal Institute for Risk Assessment (BfR), 10589, Berlin, Germany
| | - Ivonne M C M Rietjens
- Division of Toxicology, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Simone Schmitz-Spanke
- Institute and Outpatient Clinic of Occupational, Social and Environmental Medicine, University of Erlangen-Nuremberg, Henkestr. 9-11, 91054, Erlangen, Germany
| | - Gerlinde Schriever-Schwemmer
- Department of Food Chemistry and Toxicology, Institute of Applied Biosciences (IAB), Karlsruhe Institute of Technology (KIT), Adenauerring 20a, 76131, Karlsruhe, Germany
| | - Pablo Steinberg
- Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Haid-und-Neu-Str. 9, 76131, Karlsruhe, Germany
| | - Gerhard Eisenbrand
- Retired Senior Professor for Food Chemistry and Toxicology, Kühler Grund 48/1, 69126, Heidelberg, Germany.
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15
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Klapacz J, Gollapudi BB. Considerations for the Use of Mutation as a Regulatory Endpoint in Risk Assessment. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2020; 61:84-93. [PMID: 31301246 DOI: 10.1002/em.22318] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 07/08/2019] [Accepted: 07/10/2019] [Indexed: 06/10/2023]
Abstract
Assessment of a chemical's potential to cause permanent changes in the genetic code has been a common practice in the industry and regulatory settings for decades. Furthermore, the genetic toxicity battery of tests has typically been employed during the earliest stages of the research and development programs of new product development. A positive outcome from such battery has a major impact on the chemical's utility, industrial hygiene, product stewardship practices, and product life cycle analysis, among many other decisions that need to be taken by the industry, even before the registration of a chemical is undertaken. Under the prevailing regulatory paradigm, the dichotomous (yes/no) evaluation of the chemical's genotoxic potential leads to a conservative, linear no-threshold (LNT) risk assessment, unless compelling and undeniable data to the contrary can be provided to satisfy regulators, typically in a number of different global jurisdictions. With the current advent of predictive methods, new testing paradigms, mode-of-action/adverse outcome pathways, and quantitative risk assessment approaches, various stakeholders are starting to employ these state-of-the-science methodologies to further the conversation on decision making and advance the regulatory paradigm beyond the dominant LNT status quo. This commentary describes these novel methodologies, relevant biological responses, and how these can affect internal and regulatory risk assessment approaches. Environ. Mol. Mutagen. 61:84-93, 2020. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- Joanna Klapacz
- Toxicology and Environmental Research and Consulting, The Dow Chemical Company, Midland, Michigan
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16
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Boysen G, Shimoni A, Danylesko I, Varda-Bloom N, Nagler A. A simplified method for detection of N-terminal valine adducts in patients receiving treosulfan. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2019; 33:1635-1642. [PMID: 31240802 PMCID: PMC6817381 DOI: 10.1002/rcm.8509] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 06/07/2019] [Accepted: 06/18/2019] [Indexed: 05/02/2023]
Abstract
RATIONALE Treosulfan is a substance that is being studied as part of the conditioning regimen given prior to allogeneic stem cell transplantation in patients with hematological malignancies. It is known to decompose into 1,2:3,4-diepoxybutane (DEB) under physiologic conditions. In this study, we investigate whether N-terminal valine adducts can be utilized to monitor differences in DEB formation of patients receiving treosulfan as part of the conditioning regimen for transplantation. METHODS Blood samples were collected from a group of 14 transplant recipients and analyzed for N,N-(2,3-dihydroxy-1,4-butadiyl)valine (pyr-Val) and 2,3,4-trihydroxybutylvaline (THB-Val) adducts as biomarkers for drug uptake and metabolism before treosulfan treatment and 6 days after treatment. RESULTS A new direct injection liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed and validated prior to clinical analysis. The assay precision was determined by 3 replicate analyses on 3 individual days using control globin spiked with known amounts of pyr-Val and THB-Val. The intra- and inter-day precision coefficients of variance (CVs) and accuracy were < 10% and 15%, respectively. In clinical specimens, the means ± SD of pyr-Val and THB-Val background were 0.29 ± 0.10 pmol/g HB and 5.17 ± 1.7 pmol/g HB, respectively. CONCLUSIONS These values are similar to those found previously. Treosulfan treatment leads to a significant increase in pyr-Val and THB-Val adducts in each patient (Student's t-test p <0.0001). The mean ± SD amounts of adduct formed were 245.3 ± 89.6 and 210 ± 78.5 pmol/g globin for pyr-Val and THB-Val, respectively. Importantly, these results show that this direct injection method can quantitate both background and treosulfan-induced pyr-Val and THB-Val N-terminal valine globin adducts in humans.
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Affiliation(s)
- Gunnar Boysen
- Department of Environmental and Occupational Health, The University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA
- The Winthrop P. Rockefeller Cancer Institute, The University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA
| | - Avichai Shimoni
- Division of Hematology and Bone Marrow Transplantation, Chaim Sheba Medical Center, Tel-Hashomer, Israel
| | - Ivetta Danylesko
- Division of Hematology and Bone Marrow Transplantation, Chaim Sheba Medical Center, Tel-Hashomer, Israel
| | - Nira Varda-Bloom
- Division of Hematology and Bone Marrow Transplantation, Chaim Sheba Medical Center, Tel-Hashomer, Israel
| | - Arnon Nagler
- Division of Hematology and Bone Marrow Transplantation, Chaim Sheba Medical Center, Tel-Hashomer, Israel
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17
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Moore MM, Pottenger LH, House‐Knight T. Critical review of styrene genotoxicity focused on the mutagenicity/clastogenicity literature and using current organization of economic cooperation and development guidance. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2019; 60:624-663. [PMID: 30786062 PMCID: PMC6767453 DOI: 10.1002/em.22278] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 02/08/2019] [Accepted: 02/18/2019] [Indexed: 05/06/2023]
Abstract
Styrene is an important high production volume chemical used to manufacture polymeric products. In 2018, International Agency for Research on Cancer classified styrene as probably carcinogenic to humans; National Toxicology Program lists styrene as reasonably anticipated to be a human carcinogen. The genotoxicity literature for styrene and its primary metabolite, styrene 7,8-oxide (SO), begins in the 1970s. Organization of Economic Cooperation and Development (OECD) recently updated most genotoxicity test guidelines, making substantial new recommendations for assay conduct and data evaluation for the standard mutagenicity/clastogenicity assays. Thus, a critical review of the in vitro and in vivo rodent mutagenicity/clastogenicity studies for styrene and SO, based on the latest OECD recommendations, is timely. This critical review considered whether a study was optimally designed, conducted, and interpreted and provides a critical assessment of the evidence for the mutagenicity/clastogenicity of styrene/SO. Information on the ability of styrene/SO to induce other types of genotoxicity endpoints is summarized but not critically reviewed. We conclude that when styrene is metabolized to SO, it can form DNA adducts, and positive in vitro mutagenicity/clastogenicity results can be obtained. SO is mutagenic in bacteria and the in vitro mouse lymphoma gene mutation assay. No rodent in vivo mutation studies were identified. SO is clastogenic in cultured mammalian cells. Although the in vitro assays gave positive responses, styrene/SO is not clastogenic/aneugenic in vivo in rodents. In addition to providing updated information for styrene, this review demonstrates the application of the new OECD guidelines for chemicals with large genetic toxicology databases where published results may or may not be reliable. Environ. Mol. Mutagen. 2019. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- Martha M. Moore
- Ramboll124 West Capitol Avenue, Suite 1605, Little RockArkansas
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18
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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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19
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Smith RL, Cohen SM, Fukushima S, Gooderham NJ, Hecht SS, Guengerich FP, Rietjens IMCM, Bastaki M, Harman CL, McGowen MM, Taylor SV. The safety evaluation of food flavouring substances: the role of metabolic studies. Toxicol Res (Camb) 2018; 7:618-646. [PMID: 30090611 PMCID: PMC6062396 DOI: 10.1039/c7tx00254h] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 03/21/2018] [Indexed: 12/13/2022] Open
Abstract
The safety assessment of a flavour substance examines several factors, including metabolic and physiological disposition data. The present article provides an overview of the metabolism and disposition of flavour substances by identifying general applicable principles of metabolism to illustrate how information on metabolic fate is taken into account in their safety evaluation. The metabolism of the majority of flavour substances involves a series both of enzymatic and non-enzymatic biotransformation that often results in products that are more hydrophilic and more readily excretable than their precursors. Flavours can undergo metabolic reactions, such as oxidation, reduction, or hydrolysis that alter a functional group relative to the parent compound. The altered functional group may serve as a reaction site for a subsequent metabolic transformation. Metabolic intermediates undergo conjugation with an endogenous agent such as glucuronic acid, sulphate, glutathione, amino acids, or acetate. Such conjugates are typically readily excreted through the kidneys and liver. This paper summarizes the types of metabolic reactions that have been documented for flavour substances that are added to the human food chain, the methodologies available for metabolic studies, and the factors that affect the metabolic fate of a flavour substance.
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Affiliation(s)
- Robert L Smith
- Molecular Toxicology , Imperial College School of Medicine , London SW7 2AZ , UK
| | - Samuel M Cohen
- Dept. of Pathology and Microbiology , University of Nebraska Medical Centre , 983135 Nebraska Medical Centre , Omaha , NE 68198-3135 , USA
| | - Shoji Fukushima
- Japan Bioassay Research Centre , 2445 Hirasawa , Hadano , Kanagawa 257-0015 , Japan
| | - Nigel J Gooderham
- Dept. of Surgery and Cancer , Imperial College of Science , Sir Alexander Fleming Building , London SW7 2AZ , UK
| | - Stephen S Hecht
- Masonic Cancer Centre and Dept. of Laboratory Medicine and Pathology , University of Minnesota , Cancer and Cardiovascular Research Building , 2231 6th St , SE , Minneapolis , MN 55455 , USA
| | - F Peter Guengerich
- Department of Biochemistry , Vanderbilt University School of Medicine , 638B Robinson Research Building , 2200 Pierce Avenue , Nashville , Tennessee 37232-0146 , USA
| | - Ivonne M C M Rietjens
- Division of Toxicology , Wageningen University , Tuinlaan 5 , 6703 HE Wageningen , The Netherlands
| | - Maria Bastaki
- Flavor and Extract Manufacturers Association , 1101 17th Street , NW Suite 700 , Washington , DC 20036 , USA . ; ; Tel: +1 (202)293-5800
| | - Christie L Harman
- Flavor and Extract Manufacturers Association , 1101 17th Street , NW Suite 700 , Washington , DC 20036 , USA . ; ; Tel: +1 (202)293-5800
| | - Margaret M McGowen
- Flavor and Extract Manufacturers Association , 1101 17th Street , NW Suite 700 , Washington , DC 20036 , USA . ; ; Tel: +1 (202)293-5800
| | - Sean V Taylor
- Flavor and Extract Manufacturers Association , 1101 17th Street , NW Suite 700 , Washington , DC 20036 , USA . ; ; Tel: +1 (202)293-5800
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20
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Croaker A, King GJ, Pyne JH, Anoopkumar-Dukie S, Simanek V, Liu L. Carcinogenic potential of sanguinarine, a phytochemical used in 'therapeutic' black salve and mouthwash. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2017; 774:46-56. [PMID: 29173498 DOI: 10.1016/j.mrrev.2017.09.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 08/17/2017] [Accepted: 09/02/2017] [Indexed: 02/07/2023]
Abstract
Black salves are escharotic skin cancer therapies in clinical use since the mid 19th century. Sanguinaria canadensis, a major ingredient of black salve formulations, contains a number of bioactive phytochemicals including the alkaloid sanguinarine. Despite its prolonged history of clinical use, conflicting experimental results have prevented the carcinogenic potential of sanguinarine from being definitively determined. Sanguinarine has a molecular structure similar to known polyaromatic hydrocarbon carcinogens and is a DNA intercalator. Sanguinarine also generates oxidative and endoplasmic reticulum stress resulting in the unfolded protein response and the formation of 8-hydroxyguanine genetic lesions. Sanguinarine has been the subject of contradictory in vitro and in vivo genotoxicity and murine carcinogenesis test results that have delayed its carcinogenic classification. Despite this, epidemiological studies have linked mouthwash that contains sanguinarine with the development of oral leukoplakia. Sanguinarine is also proposed as an aetiological agent in gallbladder carcinoma. This literature review investigates the carcinogenic potential of sanguinarine. Reasons for contradictory genotoxicity and carcinogenesis results are explored, knowledge gaps identified and a strategy for determining the carcinogenic potential of sanguinarine especialy relating to black salve are discussed. As patients continue to apply black salve, especially to skin regions suffering from field cancerization and skin malignancies, an understanding of the genotoxic and carcinogenic potential of sanguinarine is of urgent clinical relevance.
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Affiliation(s)
- Andrew Croaker
- Southern Cross Plant Science, Southern Cross University, Lismore, NSW, Australia; Wesley Medical Research Institute, Wesley Hospital, Auchenflower, QLD, Australia; Quality Use of Medicines Network, Queensland, Australia
| | - Graham J King
- Southern Cross Plant Science, Southern Cross University, Lismore, NSW, Australia
| | - John H Pyne
- School of Medicine, University of Queensland, St Lucia, QLD, Australia
| | - Shailendra Anoopkumar-Dukie
- Quality Use of Medicines Network, Queensland, Australia; School of Pharmacy and Pharmacology, Griffith University, Gold Coast Campus, Gold Coast, QLD, Australia
| | - Vilim Simanek
- Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry, Palacký University, Olomouc, Czech Republic
| | - Lei Liu
- Southern Cross Plant Science, Southern Cross University, Lismore, NSW, Australia.
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21
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Klaus V, Bastek H, Damme K, Collins LB, Frötschl R, Benda N, Lutter D, Ellinger-Ziegelbauer H, Swenberg JA, Dietrich DR, Stemmer K. Time-matched analysis of DNA adduct formation and early gene expression as predictive tool for renal carcinogenesis in methylazoxymethanol acetate treated Eker rats. Arch Toxicol 2017; 91:3427-3438. [PMID: 28349193 DOI: 10.1007/s00204-017-1953-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 03/01/2017] [Indexed: 11/28/2022]
Abstract
Genotoxic carcinogens pose great hazard to human health. Uncertainty of current risk assessment strategies and long latency periods between first carcinogen exposure and diagnosis of tumors have raised interest in predictive biomarkers. Initial DNA adduct formation is a necessary step for genotoxin induced carcinogenesis. However, as DNA adducts not always translate into tumorigenesis, their predictive value is limited. Here we hypothesize that the combined analysis of pro-mutagenic DNA adducts along with time-matched gene expression changes could serve as a superior prediction tool for genotoxic carcinogenesis. Eker rats, heterozygous for the tuberous sclerosis (Tsc2) tumor suppressor gene and thus highly susceptible towards genotoxic renal carcinogens, were continuously treated with the DNA alkylating carcinogen methylazoxymethanol acetate (MAMAc). Two weeks of MAMAc treatment resulted in a time-dependent increase of O6-methylguanine and N7-methylguanine adducts in the kidney cortex, which was however not reflected by significant expression changes of cyto-protective genes involved in DNA repair, cell cycle arrest or apoptosis. Instead, we found a transcriptional regulation of genes involved in the tumor-related MAPK, FoxO and TGF-beta pathways. Continuous MAMAc treatment for up to 6 months resulted in a mild but significant increase of cancerous lesions. In summary, the combined analysis of DNA adducts and early gene expression changes could serve as a suitable predictive tool for genotoxicant-induced carcinogenesis.
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Affiliation(s)
- Valentina Klaus
- Computational Discovery Research, Institute for Diabetes and Obesity, Helmholtz Diabetes Center & German Center for Diabetes Research (DZD), Helmholtz Zentrum München, Neuherberg, Germany
| | - Heinke Bastek
- Human and Environmental Toxicology, University of Konstanz, Konstanz, Germany
| | - Katja Damme
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Leonard B Collins
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Roland Frötschl
- Federal Institute for Drugs and Medical Devices, Bonn, Germany
| | - Norbert Benda
- Federal Institute for Drugs and Medical Devices, Bonn, Germany
| | - Dominik Lutter
- Computational Discovery Research, Institute for Diabetes and Obesity, Helmholtz Diabetes Center & German Center for Diabetes Research (DZD), Helmholtz Zentrum München, Neuherberg, Germany
| | | | - James A Swenberg
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Daniel R Dietrich
- Human and Environmental Toxicology, University of Konstanz, Konstanz, Germany
| | - Kerstin Stemmer
- Metabolism and Cancer, Institute for Diabetes and Obesity, Helmholtz Diabetes Center & German Center for Diabetes Research (DZD), Helmholtz Zentrum München, Neuherberg, Germany.
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22
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Yao C, Foster WG, Sadeu JC, Siddique S, Zhu J, Feng YL. Screening for DNA adducts in ovarian follicles exposed to benzo[a]pyrene and cigarette smoke condensate using liquid chromatography-tandem mass spectrometry. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 575:742-749. [PMID: 27665503 DOI: 10.1016/j.scitotenv.2016.09.122] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 08/14/2016] [Accepted: 09/15/2016] [Indexed: 06/06/2023]
Abstract
A rapid mass spectrometric method was applied to non-targeted screening of DNA adducts in follicular cells (granulosa cells and theca cells) from isolated ovarian follicles that were exposed in-vitro to benzo[a]pyrene (B[a]P) and cigarette smoke condensate (CSC) for 13days of culture. The method employed a constant neutral loss (CNL) scan to identify chromatographic peaks associated to a neutral loss of deoxyribose moiety of DNA nucleosides. These peaks were subsequently analyzed by a product ion scan in tandem mass spectrometry to elucidate structures of DNA adducts. The identification was further confirmed through synthesis of proposed DNA adducts where possible. Three DNA adducts, benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide-dG (BPDE-dG), phenanthrene 1,2-quinone-dG (PheQ-dG) and B[a]P-7,8-quinone-dG (BPQ-dG) were identified in the follicular cells from isolated ovarian follicles exposed to B[a]P. Along with these three, an additional DNA adduct, 4-aminobiphenyl-dG, was identified in the follicular cells from isolated ovarian follicles exposed to CSC. The amounts of the identified DNA adducts in follicular cells increased in a dose-dependent manner for both B[a]P (0, 1.5, 5, 15 and 45ng/mL) and CSC (0, 30, 60, 90 and 130μg/mL). The results revealed that B[a]P-related DNA adducts were the major adducts in the ovarian follicular cells exposed to CSC. The results also revealed that two oxidative biomarkers, 8-hydroxy-2-deoxy guanosine (8-OH-dG) and 8-isoprostane (8-IsoP), in both B[a]P-exposed and CSC-exposed ovarian follicles had strong correlations with the three DNA adducts, BPDE-dG, BPQ-dG and PheQ-dG. A pathway to describe formation of DNA adducts was proposed based on the DNA adducts observed.
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Affiliation(s)
- Chunhe Yao
- Exposure and Biomonitoring Division, Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, 50 Colombine Driveway, AL: 0800C, Ottawa, Ontario K1A 0K9, Canada
| | - Warren G Foster
- Department of Obstetrics & Gynecology, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Jean C Sadeu
- Department of Obstetrics & Gynecology, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Shabana Siddique
- Exposure and Biomonitoring Division, Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, 50 Colombine Driveway, AL: 0800C, Ottawa, Ontario K1A 0K9, Canada
| | - Jiping Zhu
- Exposure and Biomonitoring Division, Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, 50 Colombine Driveway, AL: 0800C, Ottawa, Ontario K1A 0K9, Canada
| | - Yong-Lai Feng
- Exposure and Biomonitoring Division, Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, 50 Colombine Driveway, AL: 0800C, Ottawa, Ontario K1A 0K9, Canada.
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Dracínský M, Pohl R. Determination of the Nucleic Acid Adducts Structure at the Nucleoside/Nucleotide Level by NMR Spectroscopy. Chem Res Toxicol 2016; 28:155-65. [PMID: 25584790 DOI: 10.1021/tx5004535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
All living organisms are exposed to xenobiotics from the environment. The exposure can lead to the formation of covalent adducts of xenobiotics or their metabolites with nucleic acids (NAs).The knowledge of NA adduct structure provides valuable information n the mechanism of carcinogenesis on a molecular level. While NMR spectroscopy is extremely successful in structural analysis of many classes of molecules ranging from small inorganic and organic molecules to large biomacromolecules, the structural analysis of NA adducts by NMR spectroscopy is accompanied by some challenges. First, the structural diversity of the adducts is very large; the electrophilic species generated from the metabolism of xenobiotics can attack various atoms of the nucleobases, and new rings are frequently formed. The second challenge in the DNA adducts structure determination is the low sensitivity of NMR spectroscopy and low amount of the adducts isolated from in vivo experiments. Recent developments of NMR hardware and experimental methods have led, however, to unprecedented sensitivity. This contribution reviews NMR techniques that are commonly applied in the determination of nucleic acid adducts structure at the nucleoside/nucleotide level. These NMR techniques and the large structural heterogeneity of NA adducts are demonstrated on recent examples (mostly published after 2000) of NA adducts structure determined by NMR. Most of the examples report 2′-deoxyribonucles(t)ide derivatives, but RNA adducts are also briefly discussed. The influence of the formation of NA adducts on nucleoside conformation (particularly syn/anti orientation of the base) is also demonstrated on recent examples.
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24
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Yao C, Feng YL. A nontargeted screening method for covalent DNA adducts and DNA modification selectivity using liquid chromatography-tandem mass spectrometry. Talanta 2016; 159:93-102. [PMID: 27474284 DOI: 10.1016/j.talanta.2016.05.074] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 05/26/2016] [Accepted: 05/27/2016] [Indexed: 01/05/2023]
Abstract
A method for nontargeted screening for covalent DNA adducts was developed using combination of neutral loss scan and product ion scan in a hybrid linear-ion-trap - triple quadrupole mass spectrometer system. DNA 2'-deoxynucleosides and adducts eluted from liquid chromatography were first analyzed in neutral loss mode to screen for the neutral loss of the deoxyribose moiety ([M+H-116](+)) from the protonated molecular ion ([M+H](+)). The product ion scan was subsequently used to elucidate the structures for the molecular ions observed from the peaks in the neutral loss scan chromatogram. The synthesized DNA adducts were used to evaluate the developed method by reaction of 20-mer DNA oligonucleotide with two direct agents respectively, specifically phenyl glycidyl ether and styrene-7,8-oxide. The modification selectivity of two compounds to the four nitrogenous bases on DNA sequence was also investigated in this study. The results showed that the two compounds had different modification selectivity to the four bases. Both compounds could modify all four nitrogenous bases (i.e. adenine, guanine, thymine, and cytosine) on DNA sequences to form various covalent DNA adducts. While phenyl glycidyl ether modified almost all of thymidine on DNA sequence, styrene-7,8-oxide, on the other hand, modified only a small portion of thymidine. The developed method proved possibly a potential tool for screening of unknown DNA adducts as exposure biomarkers of contaminants to human in the environment.
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Affiliation(s)
- 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 Colombine Driveway, AL: 0800 C, Ottawa, Ontario K1A 0K9, Canada
| | - 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 Colombine Driveway, AL: 0800 C, Ottawa, Ontario K1A 0K9, Canada.
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25
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Bogen KT. Linear-No-Threshold Default Assumptions for Noncancer and Nongenotoxic Cancer Risks: A Mathematical and Biological Critique. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2016; 36:589-604. [PMID: 26249816 DOI: 10.1111/risa.12460] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
To improve U.S. Environmental Protection Agency (EPA) dose-response (DR) assessments for noncarcinogens and for nonlinear mode of action (MOA) carcinogens, the 2009 NRC Science and Decisions Panel recommended that the adjustment-factor approach traditionally applied to these endpoints should be replaced by a new default assumption that both endpoints have linear-no-threshold (LNT) population-wide DR relationships. The panel claimed this new approach is warranted because population DR is LNT when any new dose adds to a background dose that explains background levels of risk, and/or when there is substantial interindividual heterogeneity in susceptibility in the exposed human population. Mathematically, however, the first claim is either false or effectively meaningless and the second claim is false. Any dose-and population-response relationship that is statistically consistent with an LNT relationship may instead be an additive mixture of just two quasi-threshold DR relationships, which jointly exhibit low-dose S-shaped, quasi-threshold nonlinearity just below the lower end of the observed "linear" dose range. In this case, LNT extrapolation would necessarily overestimate increased risk by increasingly large relative magnitudes at diminishing values of above-background dose. The fact that chemically-induced apoptotic cell death occurs by unambiguously nonlinear, quasi-threshold DR mechanisms is apparent from recent data concerning this quintessential toxicity endpoint. The 2009 NRC Science and Decisions Panel claims and recommendations that default LNT assumptions be applied to DR assessment for noncarcinogens and nonlinear MOA carcinogens are therefore not justified either mathematically or biologically.
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26
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Maxwell O, Wagiran H. Tectonic and radioactivity impacts of 238U on groundwater-based drinking water at Gosa and Lugbe areas of Abuja, North Central Nigeria. J NUCL SCI TECHNOL 2015. [DOI: 10.1080/00223131.2015.1015467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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27
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Klapacz J, Pottenger LH, Engelward BP, Heinen CD, Johnson GE, Clewell RA, Carmichael PL, Adeleye Y, Andersen ME. Contributions of DNA repair and damage response pathways to the non-linear genotoxic responses of alkylating agents. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2015; 767:77-91. [PMID: 27036068 DOI: 10.1016/j.mrrev.2015.11.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 11/26/2015] [Accepted: 11/27/2015] [Indexed: 11/27/2022]
Abstract
From a risk assessment perspective, DNA-reactive agents are conventionally assumed to have genotoxic risks at all exposure levels, thus applying a linear extrapolation for low-dose responses. New approaches discussed here, including more diverse and sensitive methods for assessing DNA damage and DNA repair, strongly support the existence of measurable regions where genotoxic responses with increasing doses are insignificant relative to control. Model monofunctional alkylating agents have in vitro and in vivo datasets amenable to determination of points of departure (PoDs) for genotoxic effects. A session at the 2013 Society of Toxicology meeting provided an opportunity to survey the progress in understanding the biological basis of empirically-observed PoDs for DNA alkylating agents. Together with the literature published since, this review discusses cellular pathways activated by endogenous and exogenous alkylation DNA damage. Cells have evolved conserved processes that monitor and counteract a spontaneous steady-state level of DNA damage. The ubiquitous network of DNA repair pathways serves as the first line of defense for clearing of the DNA damage and preventing mutation. Other biological pathways discussed here that are activated by genotoxic stress include post-translational activation of cell cycle networks and transcriptional networks for apoptosis/cell death. The interactions of various DNA repair and DNA damage response pathways provide biological bases for the observed PoD behaviors seen with genotoxic compounds. Thus, after formation of DNA adducts, the activation of cellular pathways can lead to the avoidance of a mutagenic outcome. The understanding of the cellular mechanisms acting within the low-dose region will serve to better characterize risks from exposures to DNA-reactive agents at environmentally-relevant concentrations.
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Affiliation(s)
- Joanna Klapacz
- Toxicology & Environmental Research and Consulting, The Dow Chemical Company, Midland, MI 48674, USA.
| | - Lynn H Pottenger
- Toxicology & Environmental Research and Consulting, The Dow Chemical Company, Midland, MI 48674, USA; Current Address: Olin Corporation, Midland, MI 48674, USA
| | - Bevin P Engelward
- Department of Biological Engineering, MA Institute of Technology, Cambridge, MA 02139, USA
| | - Christopher D Heinen
- Center for Molecular Medicine, Neag Comprehensive Cancer Center, University of CT Health Center, Farmington, CT 06030, USA
| | - George E Johnson
- Institute of Life Science, College of Medicine, Swansea University, SA2 8PP, UK
| | - Rebecca A Clewell
- Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709, USA
| | - Paul L Carmichael
- Unilever, Safety & Environmental Assurance Centre, Colworth Science Park, Sharnbrook, Bedfordshire MK44 1LQ, UK
| | - Yeyejide Adeleye
- Unilever, Safety & Environmental Assurance Centre, Colworth Science Park, Sharnbrook, Bedfordshire MK44 1LQ, UK
| | - Melvin E Andersen
- Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709, USA
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28
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Yauk CL, Lambert IB, Meek MEB, Douglas GR, Marchetti F. Development of the adverse outcome pathway "alkylation of DNA in male premeiotic germ cells leading to heritable mutations" using the OECD's users' handbook supplement. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2015; 56:724-750. [PMID: 26010389 DOI: 10.1002/em.21954] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 03/31/2015] [Accepted: 04/01/2015] [Indexed: 06/04/2023]
Abstract
The Organisation for Economic Cooperation and Development's (OECD) Adverse Outcome Pathway (AOP) programme aims to develop a knowledgebase of all known pathways of toxicity that lead to adverse effects in humans and ecosystems. A Users' Handbook was recently released to provide supplementary guidance on AOP development. This article describes one AOP-alkylation of DNA in male premeiotic germ cells leading to heritable mutations. This outcome is an important regulatory endpoint. The AOP describes the biological plausibility and empirical evidence supporting that compounds capable of alkylating DNA cause germ cell mutations and subsequent mutations in the offspring of exposed males. Alkyl adducts are subject to DNA repair; however, at high doses the repair machinery becomes saturated. Lack of repair leads to replication of alkylated DNA and ensuing mutations in male premeiotic germ cells. Mutations that do not impair spermatogenesis persist and eventually are present in mature sperm. Thus, the mutations are transmitted to the offspring. Although there are some gaps in empirical support and evidence for essentiality of the key events for certain aspects of this AOP, the overall AOP is generally accepted as dogma and applies broadly to any species that produces sperm. The AOP was developed and used in an iterative process to test and refine the Users' Handbook, and is one of the first publicly available AOPs. It is our hope that this AOP will be leveraged to develop other AOPs in this field to advance method development, computational models to predict germ cell effects, and integrated testing strategies.
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Affiliation(s)
- Carole L Yauk
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, Canada
| | - Iain B Lambert
- Department of Biology, Carleton University, Ottawa, Ontario, Canada
| | - M E Bette Meek
- R. Samuel McLaughlin Centre for Population Health Risk Assessment, University of Ottawa, Ottawa, Ontario, Canada
| | - George R Douglas
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, Canada
| | - Francesco Marchetti
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, Canada
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29
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Erraguntla NK, Grant RL. Health- and vegetative-based effect screening values for ethylene. Chem Biol Interact 2015; 241:87-93. [DOI: 10.1016/j.cbi.2015.02.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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30
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Kinetic Modeling Reveals the Roles of Reactive Oxygen Species Scavenging and DNA Repair Processes in Shaping the Dose-Response Curve of KBrO₃-Induced DNA Damage. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2015:764375. [PMID: 26448819 PMCID: PMC4581570 DOI: 10.1155/2015/764375] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 07/21/2015] [Indexed: 11/24/2022]
Abstract
We have developed a kinetic model to investigate how DNA repair processes and scavengers of reactive oxygen species (ROS) can affect the dose-response shape of prooxidant induced DNA damage. We used as an example chemical KBrO3 which is activated by glutathione and forms reactive intermediates that directly interact with DNA to form 8-hydroxy-2-deoxyguanosine DNA adducts (8-OH-dG). The single strand breaks (SSB) that can result from failed base excision repair of these adducts were considered as an effect downstream from 8-OH-dG. We previously demonstrated that, in the presence of effective base excision repair, 8-OH-dG can exhibit threshold-like dose-response dependence, while the downstream SSB can still exhibit a linear dose-response. Here we demonstrate that this result holds for a variety of conditions, including low levels of GSH, the presence of additional SSB repair mechanisms, or a scavenger. It has been shown that melatonin, a terminal scavenger, inhibits KBrO3-caused oxidative damage. Our modeling revealed that sustained exposure to KBrO3 can lead to fast scavenger exhaustion, in which case the dose-response shapes for both endpoints are not substantially affected. The results are important to consider when forming conclusions on a chemical's toxicity dose dependence based on the dose-response of early genotoxic events.
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31
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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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32
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Akhmedov AT, Marín-García J. Mitochondrial DNA maintenance: an appraisal. Mol Cell Biochem 2015; 409:283-305. [DOI: 10.1007/s11010-015-2532-x] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 08/06/2015] [Indexed: 12/13/2022]
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33
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Yu R, Lai Y, Hartwell HJ, Moeller BC, Doyle-Eisele M, Kracko D, Bodnar WM, Starr TB, Swenberg JA. Formation, Accumulation, and Hydrolysis of Endogenous and Exogenous Formaldehyde-Induced DNA Damage. Toxicol Sci 2015; 146:170-82. [PMID: 25904104 PMCID: PMC4476463 DOI: 10.1093/toxsci/kfv079] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Formaldehyde is not only a widely used chemical with well-known carcinogenicity but is also a normal metabolite of living cells. It thus poses unique challenges for understanding risks associated with exposure. N(2-)hydroxymethyl-dG (N(2)-HOMe-dG) is the main formaldehyde-induced DNA mono-adduct, which together with DNA-protein crosslinks (DPCs) and toxicity-induced cell proliferation, play important roles in a mutagenic mode of action for cancer. In this study, N(2)-HOMe-dG was shown to be an excellent biomarker for direct adduction of formaldehyde to DNA and the hydrolysis of DPCs. The use of inhaled [(13)CD2]-formaldehyde exposures of rats and primates coupled with ultrasensitive nano ultra performance liquid chromatography-tandem mass spectrometry permitted accurate determinations of endogenous and exogenous formaldehyde DNA damage. The results show that inhaled formaldehyde only reached rat and monkey noses, but not tissues distant to the site of initial contact. The amounts of exogenous adducts were remarkably lower than those of endogenous adducts in exposed nasal epithelium. Moreover, exogenous adducts accumulated in rat nasal epithelium over the 28-days exposure to reach steady-state concentrations, followed by elimination with a half-life (t1/2) of 7.1 days. Additionally, we examined artifact formation during DNA preparation to ensure the accuracy of nonlabeled N(2)-HOMe-dG measurements. These novel findings provide critical new data for understanding major issues identified by the National Research Council Review of the 2010 Environmental Protection Agency's Draft Integrated Risk Information System Formaldehyde Risk Assessment. They support a data-driven need for reflection on whether risks have been overestimated for inhaled formaldehyde, whereas underappreciating endogenous formaldehyde as the primary source of exposure that results in bone marrow toxicity and leukemia in susceptible humans and rodents deficient in DNA repair.
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Affiliation(s)
- Rui Yu
- *Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina, Chapel Hill, North Carolina 27599
| | - Yongquan Lai
- *Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina, Chapel Hill, North Carolina 27599
| | - Hadley J Hartwell
- *Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina, Chapel Hill, North Carolina 27599
| | - Benjamin C Moeller
- Lovelace Respiratory Research Institute, Albuquerque, New Mexico 87108; and
| | | | - Dean Kracko
- Lovelace Respiratory Research Institute, Albuquerque, New Mexico 87108; and
| | - Wanda M Bodnar
- *Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina, Chapel Hill, North Carolina 27599
| | - Thomas B Starr
- *Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina, Chapel Hill, North Carolina 27599, TBS Associates, 7500 Rainwater Road, Raleigh, North Carolina 27615
| | - James A Swenberg
- *Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina, Chapel Hill, North Carolina 27599,
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34
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Thomas AD, Fahrer J, Johnson GE, Kaina B. Theoretical considerations for thresholds in chemical carcinogenesis. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2015; 765:56-67. [PMID: 26281768 DOI: 10.1016/j.mrrev.2015.05.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 05/11/2015] [Accepted: 05/12/2015] [Indexed: 02/08/2023]
Abstract
There is increasing evidence for non-linear relationships for gene mutations, chromosomal aberrations and even tumor incidences in response to low doses of genotoxic carcinogens. To attain the biological relevance of such non-linear responses, there is a need to identify the underlying defense mechanisms that allow tolerance to low doses of genotoxicants. This communication discusses presumptive cancer prevention mechanisms that may contribute to thresholds, i.e. points of departure, for each endpoint, from initial DNA lesion to tumor formation. We discuss a sequential order of genome protection during carcinogenesis where genotoxicant scavenging, cellular efflux, DNA repair, elimination of damaged cells by apoptosis, autophagy, silencing by DNA damage-triggered replicative senescence, and finally, elimination of transformed (premalignant) cells by the immune system are thought to be responsible for a threshold in tumor formation. We highlight DNA repair, for which experimental evidence has been recently provided to dictate a role in PoDs. In conclusion, from a theoretical perspective it is reasonable to posit that tolerance to low dose levels exists for each requisite step of tumor formation and these tolerance mechanisms are critical in determining thresholds in chemical carcinogenesis.
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Affiliation(s)
- Adam D Thomas
- Institute of Toxicology, University Medical Centre, Mainz, Germany
| | - Jörg Fahrer
- Institute of Toxicology, University Medical Centre, Mainz, Germany
| | - George E Johnson
- Institue of Life Science, College of Medicine, Swansea, Wales, United Kingdom
| | - Bernd Kaina
- Institute of Toxicology, University Medical Centre, Mainz, Germany.
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MacGregor JT, Frötschl R, White PA, Crump KS, Eastmond DA, Fukushima S, Guérard M, Hayashi M, Soeteman-Hernández LG, Johnson GE, Kasamatsu T, Levy DD, Morita T, Müller L, Schoeny R, Schuler MJ, Thybaud V. IWGT report on quantitative approaches to genotoxicity risk assessment II. Use of point-of-departure (PoD) metrics in defining acceptable exposure limits and assessing human risk. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2015; 783:66-78. [DOI: 10.1016/j.mrgentox.2014.10.008] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 10/18/2014] [Indexed: 11/26/2022]
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Singaravelu SR, Sellappa S. Increased cytogenetic abnormalities in exfoliated oral mucosal cells of South Indian foundry workers. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:2721-2725. [PMID: 25205155 DOI: 10.1007/s11356-014-3543-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 09/01/2014] [Indexed: 06/03/2023]
Abstract
Biomonitoring offers a valuable tool to estimate the genetic risk as of exposure to genotoxic agents. Here, we intend to assess the potential cytogenetic damage related with occupational exposure to polycyclic aromatic hydrocarbons by evaluating the genetic damages in exfoliated buccal epithelial cells of foundry workers via counting micronucleus (MNs) and other nuclear abnormalities (NAs). This was a cross-sectional study and all study subjects were male . Exfoliated buccal mucosal cells were obtained from 100 subjects involved in either foundry molding or melting processes, and 100 controls matched for sex, age, and smoking from the area of Coimbatore city, Southern India. For each individual, 2000 exfoliated buccal cells were analyzed. Significantly, there was a higher frequency of MN in the exposed workers than in the controls (P < 0.05). Smoking was associated with the increased frequencies of micronuclei and NAs in the buccal epithelium of both the control and the exposed groups. Smoking represented significant factors in terms of increasing the production of MN when the control and the exposed groups were compared (P < 0.05). The results specify that buccal cells of foundry workers display increased levels of genotoxicity and these biomarker responses may be related to the increased cancer risk. These results conclude that the studied individuals are at a risk group and they require periodical biological monitoring and proper care which is essential for them.
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Affiliation(s)
- Saranya Ramalingam Singaravelu
- Molecular Diagnosis and Drug Discovery Laboratory, Department of Biotechnology, School of Life Sciences, Karpagam University, Coimbatore, Tamilnadu, India,
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Guérard M, Baum M, Bitsch A, Eisenbrand G, Elhajouji A, Epe B, Habermeyer M, Kaina B, Martus H, Pfuhler S, Schmitz C, Sutter A, Thomas A, Ziemann C, Froetschl R. Assessment of mechanisms driving non-linear dose–response relationships in genotoxicity testing. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2015; 763:181-201. [DOI: 10.1016/j.mrrev.2014.11.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 10/31/2014] [Accepted: 11/01/2014] [Indexed: 01/15/2023]
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38
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Greim H, Albertini RJ. Cellular response to the genotoxic insult: the question of threshold for genotoxic carcinogens. Toxicol Res (Camb) 2015. [DOI: 10.1039/c4tx00078a] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Maintenance of cellular integrity is crucial for its physiological function, which is constantly threatened by DNA damage arising from numerous intrinsic and environmental sources.
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Nakamura J, Mutlu E, Sharma V, Collins L, Bodnar W, Yu R, Lai Y, Moeller B, Lu K, Swenberg J. The endogenous exposome. DNA Repair (Amst) 2014; 19:3-13. [PMID: 24767943 PMCID: PMC4097170 DOI: 10.1016/j.dnarep.2014.03.031] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The concept of the Exposome is a compilation of diseases and one's lifetime exposure to chemicals, whether the exposure comes from environmental, dietary, or occupational exposures; or endogenous chemicals that are formed from normal metabolism, inflammation, oxidative stress, lipid peroxidation, infections, and other natural metabolic processes such as alteration of the gut microbiome. In this review, we have focused on the endogenous exposome, the DNA damage that arises from the production of endogenous electrophilic molecules in our cells. It provides quantitative data on endogenous DNA damage and its relationship to mutagenesis, with emphasis on when exogenous chemical exposures that produce identical DNA adducts to those arising from normal metabolism cause significant increases in total identical DNA adducts. We have utilized stable isotope labeled chemical exposures of animals and cells, so that accurate relationships between endogenous and exogenous exposures can be determined. Advances in mass spectrometry have vastly increased both the sensitivity and accuracy of such studies. Furthermore, we have clear evidence of which sources of exposure drive low dose biology that results in mutations and disease. These data provide much needed information to impact quantitative risk assessments, in the hope of moving towards the use of science, rather than default assumptions.
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Affiliation(s)
- Jun Nakamura
- University of North Carolina, Chapel Hill, NC, United States
| | - Esra Mutlu
- University of North Carolina, Chapel Hill, NC, United States
| | - Vyom Sharma
- University of North Carolina, Chapel Hill, NC, United States
| | - Leonard Collins
- University of North Carolina, Chapel Hill, NC, United States
| | - Wanda Bodnar
- University of North Carolina, Chapel Hill, NC, United States
| | - Rui Yu
- University of North Carolina, Chapel Hill, NC, United States
| | - Yongquan Lai
- University of North Carolina, Chapel Hill, NC, United States
| | - Benjamin Moeller
- University of North Carolina, Chapel Hill, NC, United States; Lovelace Respiratory Research Institute, Albuquerque, NM, United States
| | - Kun Lu
- University of North Carolina, Chapel Hill, NC, United States
| | - James Swenberg
- University of North Carolina, Chapel Hill, NC, United States.
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40
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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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Xu Y, Cui B, Ran R, Liu Y, Chen H, Kai G, Shi J. Risk assessment, formation, and mitigation of dietary acrylamide: current status and future prospects. Food Chem Toxicol 2014; 69:1-12. [PMID: 24713263 DOI: 10.1016/j.fct.2014.03.037] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 03/23/2014] [Accepted: 03/28/2014] [Indexed: 10/25/2022]
Abstract
Acrylamide (AA) was firstly detected in food in 2002, and since then, studies on AA analysis, occurrence, formation, toxicity, risk assessment and mitigation have been extensively carried out, which have greatly advanced understanding of this particular biohazard at both academic and industrial levels. There is considerable variation in the levels of AA in different foods and different brands of the same food; therefore, so far, a general upper limit for AA in food is not available. In addition, the link of dietary AA to human cancer is still under debate, although AA has been known as a potential cause of various toxic effects including carcinogenic effects in experimental animals. Furthermore, the oxidized metabolite of AA, glycidamide (GA), is more toxic than AA. Both AA and GA can form adducts with protein, DNA, and hemoglobin, and some of those adducts can serve as biomarkers for AA exposure; their potential roles in the linking of AA to human cancer, reproductive defects or other diseases, however, are unclear. This review addresses the state-of-the-art understanding of AA, focusing on risk assessment, mechanism of formation and strategies of mitigation in foods. The potential application of omics to AA risk assessment is also discussed.
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Affiliation(s)
- Yi Xu
- National Center for Molecular Characterization of Genetically Modified Organisms, School of Life Science and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, PR China; College of Life and Environmental Sciences, Shanghai Normal University, 100 Guilin Road, Xuhui District, Shanghai 200234, PR China
| | - Bo Cui
- National Center for Molecular Characterization of Genetically Modified Organisms, School of Life Science and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, PR China; College of Life Science, Sichuan Agricultural University, 46 Xinkang Road, Yucheng District, Ya'an City, Sichuan Province 625014, PR China
| | - Ran Ran
- National Center for Molecular Characterization of Genetically Modified Organisms, School of Life Science and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, PR China
| | - Ying Liu
- National Center for Molecular Characterization of Genetically Modified Organisms, School of Life Science and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, PR China
| | - Huaping Chen
- College of Life Science, Sichuan Agricultural University, 46 Xinkang Road, Yucheng District, Ya'an City, Sichuan Province 625014, PR China
| | - Guoyin Kai
- College of Life and Environmental Sciences, Shanghai Normal University, 100 Guilin Road, Xuhui District, Shanghai 200234, PR China.
| | - Jianxin Shi
- National Center for Molecular Characterization of Genetically Modified Organisms, School of Life Science and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, PR China.
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Sharma V, Collins LB, Clement JM, Zhang Z, Nakamura J, Swenberg JA. Molecular dosimetry of endogenous and exogenous O(6)-methyl-dG and N7-methyl-G adducts following low dose [D3]-methylnitrosourea exposures in cultured human cells. Chem Res Toxicol 2014; 27:480-2. [PMID: 24628573 PMCID: PMC3998766 DOI: 10.1021/tx5000602] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
For DNA-reactive chemicals, a low dose linear assessment of cancer risk is the science policy default. In the present study, we quantitated the endogenous and exogenous N7-methyl-G and O(6)-methyl-dG adducts in human lymphoblastoid cells exposed to low dose [D3]-methylnitrosourea. Endogenous amounts of both adducts remained nearly constant, while the exogenous adducts showed linear dose-responses. The data show that O(6)-methyl-dG adducts ≥1.8/10(8) dG correlated with published studies that demonstrated significant increases of mutations under these conditions. The combined results do not support linear extrapolations to zero when data are available for science-based regulations.
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Affiliation(s)
- Vyom Sharma
- Department of Environmental Sciences and Engineering, University of North Carolina , Campus Box 7431, Chapel Hill, North Carolina 27599-7431, United States
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Becker K, Thomas AD, Kaina B. Does increase in DNA repair allow "tolerance-to-insult" in chemical carcinogenesis? Skin tumor experiments with MGMT-overexpressing mice. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2014; 55:145-150. [PMID: 24519900 DOI: 10.1002/em.21834] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 10/25/2013] [Accepted: 11/11/2013] [Indexed: 06/03/2023]
Abstract
Several genotoxicity endpoints have been evaluated to define nonlinear dose-responses for SN 1 and SN 2 alkylating genotoxicants. Dose-response studies acknowledging the process of multistage tumorigenesis are important; however, data pertaining nonlinearity are not yet available. In this communication, the role of DNA repair in the dose-response relationship for benign papillomas was examined using the two-stage skin carcinogenesis protocol. The data obtained with O(6) -methylguanine-DNA methyltransferase (MGMT) overexpressing mice in which papillomas were induced by a single topical treatment with N-methyl-N-nitrosourea (MNU) followed by promotion with 12-O-tetradecanoylphorbol-13-acetate are reported. As MGMT efficiently protects cells from mutations by repairing O(6) -methylguanine, a miscoding lesion induced by MNU, the question whether MGMT is able to nullify carcinogenic lesions to an extent where they would be considered nonhazardous has been addressed. It is shown here that MGMT overexpression significantly protects against, but does not completely nullify, the effect of MNU in tumor initiation. The possible mechanisms involved have also been discussed.
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Affiliation(s)
- Klaus Becker
- Institute of Plant Genetics and Crop Plant Research, Gatersleben, Germany
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44
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Pottenger LH, Andrews LS, Bachman AN, Boogaard PJ, Cadet J, Embry MR, Farmer PB, Himmelstein MW, Jarabek AM, Martin EA, Mauthe RJ, Persaud R, Preston RJ, Schoeny R, Skare J, Swenberg JA, Williams GM, Zeiger E, Zhang F, Kim JH. An organizational approach for the assessment of DNA adduct data in risk assessment: case studies for aflatoxin B1, tamoxifen and vinyl chloride. Crit Rev Toxicol 2014; 44:348-91. [DOI: 10.3109/10408444.2013.873768] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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45
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Budinsky RA, Schrenk D, Simon T, Van den Berg M, Reichard JF, Silkworth JB, Aylward LL, Brix A, Gasiewicz T, Kaminski N, Perdew G, Starr TB, Walker NJ, Rowlands JC. Mode of action and dose–response framework analysis for receptor-mediated toxicity: The aryl hydrocarbon receptor as a case study. Crit Rev Toxicol 2013; 44:83-119. [DOI: 10.3109/10408444.2013.835787] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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46
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Goel S, Evans-Johnson JA, Georgieva NI, Boysen G. Exposure profiling of reactive compounds in complex mixtures. Toxicology 2013; 313:145-150. [PMID: 23219592 PMCID: PMC4868061 DOI: 10.1016/j.tox.2012.11.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Revised: 11/13/2012] [Accepted: 11/25/2012] [Indexed: 01/16/2023]
Abstract
Humans are constantly exposed to mixtures, such as tobacco smoke, exhaust from diesel, gasoline or new bio-fuels, containing several 1000 compounds, including many known human carcinogens. Covalent binding of reactive compounds or their metabolites to DNA and formation of stable adducts is believed to be the causal link between exposure and carcinogenesis. DNA and protein adducts are well established biomarkers for the internal dose of reactive compounds or their metabolites and are an integral part of science-based risk assessment. However, technical limitations have prevented comprehensive detection of a broad spectrum of adducts simultaneously. Therefore, most studies have focused on measurement of abundant individual adducts. These studies have produced valuable insight into the metabolism of individual carcinogens, but they are insufficient for risk assessment of exposure to complex mixtures. To overcome this limitation, we present herein proof-of-principle for comprehensive exposure assessment, using N-terminal valine adduct profiles as a biomarker. The reported method is based on our previously established immunoaffinity liquid chromatography-tandem mass spectrometry (LC-MS/MS) method with modification to enrich all N-terminal valine alkylated peptides. The method was evaluated using alkylated peptide standards and globin reacted in vitro with alkylating agents (1,2-epoxy-3-butene, 1,2:3,4-diepoxybutane, propylene oxide, styrene oxide, N-ethyl-N-nitrosourea and methyl methanesulfonate), known to form N-terminal valine adducts. To demonstrate proof-of-principle, the method was successfully applied to globin from mice treated with four model compounds. The results suggest that this novel approach might be suitable for in vivo biomonitoring.
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Key Words
- 1,2 epoxy-3-butene
- 1,2:3,4-diepoxybutane
- 1,3-butadiene
- 1-hydroxy (or 2-hydroxy)-propyl-valine
- 1-phenyl-2-hydroxyethyl-valine or 2-phenyl-2-hydroxyethyl-valine
- 2,3,4-trihydroxybutyl-valine
- 3,4-epoxy-1,2-butanediol
- BD
- Biomarkers
- Biomonitoring
- DEB
- EB
- EB-diol
- ENU
- ENU-Val
- Et-Val
- FA
- H(2)N-Val
- HB-Val
- HP-Val
- Hb
- IA
- LC–MS/MS
- MMS
- Me-Val
- Mixtures
- Multiple exposure detection
- N,N-(2,3-dihydroxy-1,4-butadiyl)-valine
- N-(2-hydroxy-3-buten-1-yl)-valine
- N-ethyl-N-nitrosourea
- N-terminal valine adducts
- PO
- SO
- SO-Val
- THB-Val
- carbamoylated-valine
- ethyl-valine
- formic acid
- hemoglobin
- immunoaffinity
- liquid chromatography–tandem mass spectrometry
- methyl-methanesulfonate
- methyl-valine
- non-alkylated-valine
- propylene oxide
- pyr-Val
- styrene oxide
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Affiliation(s)
- Shilpi Goel
- Department of Environmental and Occupational Health, The Winthrop P. Rockefeller Cancer Institute at The University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Julie A Evans-Johnson
- Department of Environmental and Occupational Health, The Winthrop P. Rockefeller Cancer Institute at The University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Nadia I Georgieva
- Department of Environmental and Occupational Health, The Winthrop P. Rockefeller Cancer Institute at The University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Gunnar Boysen
- Department of Environmental and Occupational Health, The Winthrop P. Rockefeller Cancer Institute at The University of Arkansas for Medical Sciences, Little Rock, AR, United States
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47
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Albertini RJ. Vinyl acetate monomer (VAM) genotoxicity profile: Relevance for carcinogenicity. Crit Rev Toxicol 2013; 43:671-706. [DOI: 10.3109/10408444.2013.827151] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Boobis A, Flari V, Gosling JP, Hart A, Craig P, Rushton L, Idahosa-Taylor E. Interpretation of the margin of exposure for genotoxic carcinogens – Elicitation of expert knowledge about the form of the dose response curve at human relevant exposures. Food Chem Toxicol 2013; 57:106-18. [DOI: 10.1016/j.fct.2013.03.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Revised: 02/06/2013] [Accepted: 03/02/2013] [Indexed: 01/08/2023]
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Moeller BC, Recio L, Green A, Sun W, Wright FA, Bodnar WM, Swenberg JA. Biomarkers of exposure and effect in human lymphoblastoid TK6 cells following [13C2]-acetaldehyde exposure. Toxicol Sci 2013; 133:1-12. [PMID: 23425604 PMCID: PMC3627555 DOI: 10.1093/toxsci/kft029] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Accepted: 02/11/2013] [Indexed: 01/13/2023] Open
Abstract
The dose-response relationship for biomarkers of exposure (N(2)-ethylidene-dG adducts) and effect (cell survival and micronucleus formation) was determined across 4.5 orders of magnitude (50nM-2mM) using [(13)C2]-acetaldehyde exposures to human lymphoblastoid TK6 cells for 12h. There was a clear increase in exogenous N (2)-ethylidene-dG formation at exposure concentrations ≥ 1µM, whereas the endogenous adducts remained nearly constant across all exposure concentrations, with an average of 3.0 adducts/10(7) dG. Exogenous adducts were lower than endogenous adducts at concentrations ≤ 10µM and were greater than endogenous adducts at concentrations ≥ 250µM. When the endogenous and exogenous adducts were summed together, statistically significant increases in total adduct formation over the endogenous background occurred at 50µM. Cell survival and micronucleus formation were monitored across the exposure range and statistically significant decreases in cell survival and increases in micronucleus formation occurred at ≥ 1000µM. This research supports the hypothesis that endogenously produced reactive species, including acetaldehyde, are always present and constitute the majority of the observed biological effects following very low exposures to exogenous acetaldehyde. These data can replace default assumptions of linear extrapolation to very low doses of exogenous acetaldehyde for risk prediction.
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Affiliation(s)
- Benjamin C. Moeller
- *Curriculum in Toxicology, University of North Carolina, Chapel Hill, North Carolina 27599
| | | | | | - Wei Sun
- ‡Biostatistics, Gillings School of Global Public Health
- §Department of Genetics, School of Medicine, and
| | | | - Wanda M. Bodnar
- ¶Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina 27599
| | - James A. Swenberg
- *Curriculum in Toxicology, University of North Carolina, Chapel Hill, North Carolina 27599
- ¶Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina 27599
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Affiliation(s)
- Natalia Tretyakova
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA.
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