1
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Lu YY, Chen HE, Chen WL. Negative Association of Serum β-Cryptoxanthin With Benzene and Its Derivatives. JOURNAL OF THE AMERICAN NUTRITION ASSOCIATION 2024:1-7. [PMID: 38227813 DOI: 10.1080/27697061.2023.2300429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 12/24/2023] [Indexed: 01/18/2024]
Abstract
OBJECTIVE Benzene is widely recognized as a potential carcinogen. Furthermore, the deficiency of specific nutrients may render individuals more vulnerable to cancer. For instance, β-cryptoxanthin, which possesses anti-inflammatory, antioxidant, and anticancer properties, has been identified as one such nutrient. Elevated benzene levels and reduced β-cryptoxanthin levels are reportedly correlated with an augmented susceptibility to cancer. To date, whether these 2 substances are linked with one another in the above correlation is yet to be determined. METHOD This study included 1358 participants with data on the serum concentration of β-cryptoxanthin as well as benzene and its derivatives. The data were sourced from the 2003-2004 National Health and Nutrition Examination Survey, a cross-sectional survey of the noninstitutionalized US population. Headspace solid-phase microextraction with gas chromatography and mass spectrometry was used to measure serum benzene and its derivatives, while high-performance liquid chromatography using multiwavelength photodiode-array absorbance detection was employed to quantify serum β-cryptoxanthin. RESULTS In this study, male and female participants showed average β-cryptoxanthin levels of 9.10 ± 6.35 and 9.92 ± 8.95 ug/dL, respectively (p = 0.049). Styrene exhibited the strongest correlation with the change in β-cryptoxanthin concentration (β = -3.30, p for trend <0.001) upon comparing highest-quartile participants with those in the lowest quartile, followed by benzene (β = -2.95, p for trend <0.001), toluene (β = -2.90, p for trend <0.001), and ethylbenzene (β = -1.43, p for trend = 0.09). Subgroup analysis by sex displayed a statistically significant negative correlation of β-cryptoxanthin with benzene, styrene, and toluene in both the unadjusted and multivariate-adjusted models. CONCLUSIONS The sera of noninstitutionalized US individuals exhibit a negative association of β-cryptoxanthin levels with benzene and its derivatives. Styrene demonstrates the strongest link with a substantial decline in serum β-cryptoxanthin levels, followed by benzene, toluene, and ethylbenzene.
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Affiliation(s)
- Yu-Yang Lu
- Department of Pediatrics, Tri-Service General Hospital, School of Medicine, National Defense Medical Center, Taipei, Taiwan
| | - Hao-En Chen
- Department of Surgery, Taichung Armed Forces General Hospital, Taichung, Taiwan
| | - Wei-Liang Chen
- Division of Family Medicine, Department of Family and Community Medicine, Tri-Service General Hospital, School of Medicine, National Defense Medical Center, Taipei, Taiwan
- Division of Geriatric Medicine, Department of Family and Community Medicine, Tri-Service General Hospital, School of Medicine, National Defense Medical Center, Taipei, Taiwan
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2
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Wan W, Peters S, Portengen L, Olsson A, Schüz J, Ahrens W, Schejbalova M, Boffetta P, Behrens T, Brüning T, Kendzia B, Consonni D, Demers PA, Fabiánová E, Fernández-Tardón G, Field JK, Forastiere F, Foretova L, Guénel P, Gustavsson P, Jöckel KH, Karrasch S, Landi MT, Lissowska J, Barul C, Mates D, McLaughlin JR, Merletti F, Migliore E, Richiardi L, Pándics T, Pohlabeln H, Siemiatycki J, Świątkowska B, Wichmann HE, Zaridze D, Ge C, Straif K, Kromhout H, Vermeulen R. Occupational Benzene Exposure and Lung Cancer Risk: A Pooled Analysis of 14 Case-Control Studies. Am J Respir Crit Care Med 2024; 209:185-196. [PMID: 37812782 PMCID: PMC10806413 DOI: 10.1164/rccm.202306-0942oc] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 10/06/2023] [Indexed: 10/11/2023] Open
Abstract
Rationale: Benzene has been classified as carcinogenic to humans, but there is limited evidence linking benzene exposure to lung cancer. Objectives: We aimed to examine the relationship between occupational benzene exposure and lung cancer. Methods: Subjects from 14 case-control studies across Europe and Canada were pooled. We used a quantitative job-exposure matrix to estimate benzene exposure. Logistic regression models assessed lung cancer risk across different exposure indices. We adjusted for smoking and five main occupational lung carcinogens and stratified analyses by smoking status and lung cancer subtypes. Measurements and Main Results: Analyses included 28,048 subjects (12,329 cases, 15,719 control subjects). Lung cancer odds ratios ranged from 1.12 (95% confidence interval, 1.03-1.22) to 1.32 (95% confidence interval, 1.18-1.48) (Ptrend = 0.002) for groups with the lowest and highest cumulative occupational exposures, respectively, compared with unexposed subjects. We observed an increasing trend of lung cancer with longer duration of exposure (Ptrend < 0.001) and a decreasing trend with longer time since last exposure (Ptrend = 0.02). These effects were seen for all lung cancer subtypes, regardless of smoking status, and were not influenced by specific occupational groups, exposures, or studies. Conclusions: We found consistent and robust associations between different dimensions of occupational benzene exposure and lung cancer after adjusting for smoking and main occupational lung carcinogens. These associations were observed across different subgroups, including nonsmokers. Our findings support the hypothesis that occupational benzene exposure increases the risk of developing lung cancer. Consequently, there is a need to revisit published epidemiological and molecular data on the pulmonary carcinogenicity of benzene.
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Affiliation(s)
- Wenxin Wan
- Institute for Risk Assessment Sciences, Utrecht University, Utrecht, the Netherlands
| | - Susan Peters
- Institute for Risk Assessment Sciences, Utrecht University, Utrecht, the Netherlands
| | - Lützen Portengen
- Institute for Risk Assessment Sciences, Utrecht University, Utrecht, the Netherlands
| | - Ann Olsson
- International Agency for Research on Cancer/World Health Organization, Lyon, France
| | - Joachim Schüz
- International Agency for Research on Cancer/World Health Organization, Lyon, France
| | - Wolfgang Ahrens
- Leibniz Institute for Prevention Research and Epidemiology, Bremen, Germany
- Faculty of Mathematics and Computer Science, Institute of Statistics, University of Bremen, Bremen, Germany
| | - Miriam Schejbalova
- Institute of Hygiene and Epidemiology, First Faculty of Medicine, Charles University, Prague, Czechia
| | - Paolo Boffetta
- Stony Brook Cancer Center, Stony Brook University, Stony Brook, New York
- Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
| | - Thomas Behrens
- Institute for Prevention and Occupational Medicine of the German Social Accident Insurance, Institute of the Ruhr University, Bochum, Germany
| | - Thomas Brüning
- Institute for Prevention and Occupational Medicine of the German Social Accident Insurance, Institute of the Ruhr University, Bochum, Germany
| | - Benjamin Kendzia
- Institute for Prevention and Occupational Medicine of the German Social Accident Insurance, Institute of the Ruhr University, Bochum, Germany
| | - Dario Consonni
- Epidemiology Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Paul A. Demers
- Occupational Cancer Research Centre, Ontario Health, Toronto, Ontario, Canada
| | - Eleonóra Fabiánová
- Regional Authority of Public Health, Banská Bystrica, Slovakia
- Faculty of Health, Catholic University, Ružomberok, Slovakia
| | - Guillermo Fernández-Tardón
- Consortium for Biomedical Research in Epidemiology and Public Health, Madrid, Spain
- Health Research Institute of Asturias, University Institute of Oncology of Asturias – Cajastur Social Program, University of Oviedo, Oviedo, Spain
| | - John K. Field
- Roy Castle Lung Cancer Research Programme, Department of Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool, United Kingdom
| | | | | | - Pascal Guénel
- Center for Research in Epidemiology and Population Health, Team Exposome and Heredity, U1018 Institut national de la santé et de la recherche médicale, University of Paris-Saclay, Villejuif, France
| | - Per Gustavsson
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Karl-Heinz Jöckel
- Institute for Medical Informatics, Biometry and Epidemiology, University Hospital Essen, Essen, Germany
| | - Stefan Karrasch
- Institute and Clinic for Occupational, Social and Environmental Medicine, University Hospital, and
- Comprehensive Pneumology Center Munich, Member of the German Center for Lung Research, Munich, Germany
- Institute of Epidemiology, Helmholtz Zentrum München – German Research Center for Environmental Health, Neuherberg, Germany
| | - Maria Teresa Landi
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, Maryland
| | - Jolanta Lissowska
- Epidemiology Unit, Department of Cancer Epidemiology and Prevention, M. Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland
| | - Christine Barul
- Université Rennes, Institut national de la santé et de la recherche médicale, École des hautes études en santé publique, Institut de recherche en santé, environnement et travail, UMR_S 1085, Pointe-à-Pitre, France
| | - Dana Mates
- National Institute of Public Health, Bucharest, Romania
| | - John R. McLaughlin
- Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | - Franco Merletti
- Cancer Epidemiology Unit, Department of Medical Sciences, University of Turin, Turin, Italy
| | - Enrica Migliore
- Cancer Epidemiology Unit, Department of Medical Sciences, University of Turin, Turin, Italy
| | - Lorenzo Richiardi
- Cancer Epidemiology Unit, Department of Medical Sciences, University of Turin, Turin, Italy
| | | | - Hermann Pohlabeln
- Leibniz Institute for Prevention Research and Epidemiology, Bremen, Germany
| | - Jack Siemiatycki
- Department of Social and Preventive Medicine, University of Montreal, Montreal, Quebec, Canada
| | - Beata Świątkowska
- Department of Environmental Epidemiology, The Nofer Institute of Occupational Medicine, Lodz, Poland
| | - Heinz-Erich Wichmann
- Institut für Medizinische Informatik Biometrie Epidemiologie, Ludwig-Maximilians-Universität München, Munich, Germany
- Comprehensive Pneumology Center Munich, Member of the German Center for Lung Research, Munich, Germany
| | - David Zaridze
- Department of Cancer Epidemiology and Prevention, N.N. Blokhin National Research Center of Oncology, Moscow, Russia
| | - Calvin Ge
- Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek, Utrecht, the Netherlands
| | - Kurt Straif
- ISGlobal, Barcelona, Spain; and
- Boston College, Boston, Massachusetts
| | - Hans Kromhout
- Institute for Risk Assessment Sciences, Utrecht University, Utrecht, the Netherlands
| | - Roel Vermeulen
- Institute for Risk Assessment Sciences, Utrecht University, Utrecht, the Netherlands
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3
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Cen Z, Lu B, Ji Y, Chen J, Liu Y, Jiang J, Li X, Li X. Virus-induced breath biomarkers: A new perspective to study the metabolic responses of COVID-19 vaccinees. Talanta 2023; 260:124577. [PMID: 37116359 PMCID: PMC10122548 DOI: 10.1016/j.talanta.2023.124577] [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: 02/14/2023] [Revised: 04/15/2023] [Accepted: 04/18/2023] [Indexed: 04/30/2023]
Abstract
Coronavirus disease 2019 (COVID-19) vaccines can protect people from the infection; however, the action mechanism of vaccine-mediated metabolism remains unclear. Herein, we performed breath tests in COVID-19 vaccinees that revealed metabolic reprogramming induced by protective immune responses. In total, 204 breath samples were obtained from COVID-19 vaccinees and non-vaccinated controls, wherein numerous volatile organic compounds (VOCs) were detected by comprehensive two-dimensional gas chromatography and time-of-flight mass spectrometry system. Subsequently, 12 VOCs were selected as biomarkers to construct a signature panel using alveolar gradients and machine learning-based procedure. The signature panel could distinguish vaccinees from control group with a high prediction performance (AUC, 0.9953; accuracy, 94.42%). The metabolic pathways of these biomarkers indicated that the host-pathogen interactions enhanced enzymatic activity and microbial metabolism in the liver, lung, and gut, potentially constituting the dominant action mechanism of vaccine-driven metabolic regulation. Thus, our findings of this study highlight the potential of measuring exhaled VOCs as rapid, non-invasive biomarkers of viral infections. Furthermore, breathomics appears as an alternative for safety evaluation of biological agents and disease diagnosis.
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Affiliation(s)
- Zhengnan Cen
- Department of Environmental Science & Engineering, Fudan University, Shanghai, 200438, PR China
| | - Bingqing Lu
- Department of Environmental Science & Engineering, Fudan University, Shanghai, 200438, PR China
| | - Yongyan Ji
- Department of Environmental Science & Engineering, Fudan University, Shanghai, 200438, PR China
| | - Jian Chen
- Department of Environmental Science & Engineering, Fudan University, Shanghai, 200438, PR China
| | - Yongqian Liu
- Department of Environmental Science & Engineering, Fudan University, Shanghai, 200438, PR China
| | - Jiakui Jiang
- Department of Environmental Science & Engineering, Fudan University, Shanghai, 200438, PR China
| | - Xue Li
- Institute of Mass Spectrometry and Atmospheric Environment, Jinan University, Guangzhou, 510632, PR China
| | - Xiang Li
- Department of Environmental Science & Engineering, Fudan University, Shanghai, 200438, PR China.
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4
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Acute cytotoxicity, genotoxicity, and apoptosis induced by petroleum VOC emissions in A549 cell line. Toxicol In Vitro 2022; 83:105409. [DOI: 10.1016/j.tiv.2022.105409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 04/28/2022] [Accepted: 05/30/2022] [Indexed: 11/27/2022]
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5
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Abplanalp WT, Wickramasinghe NS, Sithu SD, Conklin DJ, Xie Z, Bhatnagar A, Srivastava S, O'Toole TE. Benzene Exposure Induces Insulin Resistance in Mice. Toxicol Sci 2020; 167:426-437. [PMID: 30346588 DOI: 10.1093/toxsci/kfy252] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Benzene is a ubiquitous pollutant associated with hematotoxicity but its metabolic effects are unknown. We sought to determine if and how exposure to volatile benzene impacted glucose handling. We exposed wild type C57BL/6 mice to volatile benzene (50 ppm × 6 h/day) or HEPA-filtered air for 2 or 6 weeks and measured indices of oxidative stress, inflammation, and insulin signaling. Compared with air controls, we found that mice inhaling benzene demonstrated increased plasma glucose (p = .05), insulin (p = .03), and HOMA-IR (p = .05), establishing a state of insulin and glucose intolerance. Moreover, insulin-stimulated Akt phosphorylation was diminished in the liver (p = .001) and skeletal muscle (p = .001) of benzene-exposed mice, accompanied by increases in oxidative stress and Nf-κb phosphorylation (p = .025). Benzene-exposed mice also demonstrated elevated levels of Mip1-α transcripts and Socs1 (p = .001), but lower levels of Irs-2 tyrosine phosphorylation (p = .0001). Treatment with the superoxide dismutase mimetic, TEMPOL, reversed benzene-induced effects on oxidative stress, Nf-κb phosphorylation, Socs1 expression, Irs-2 tyrosine phosphorylation, and systemic glucose intolerance. These findings suggest that exposure to benzene induces insulin resistance and that this may be a sensitive indicator of inhaled benzene toxicity. Persistent ambient benzene exposure may be a heretofore unrecognized contributor to the global human epidemics of diabetes and cardiovascular disease.
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Affiliation(s)
- Wesley T Abplanalp
- Department of Medicine, Diabetes and Obesity Center, University of Louisville, Louisville, Kentucky 40292
| | - Nalinie S Wickramasinghe
- Department of Medicine, Diabetes and Obesity Center, University of Louisville, Louisville, Kentucky 40292.,Envirome Institute, University of Louisville, Louisville, Kentucky 40292.,University of Louisville Superfund Research Center, Louisville, Kentucky 40202
| | - Srinivas D Sithu
- Department of Medicine, Diabetes and Obesity Center, University of Louisville, Louisville, Kentucky 40292.,Envirome Institute, University of Louisville, Louisville, Kentucky 40292.,University of Louisville Superfund Research Center, Louisville, Kentucky 40202
| | - Daniel J Conklin
- Department of Medicine, Diabetes and Obesity Center, University of Louisville, Louisville, Kentucky 40292.,Envirome Institute, University of Louisville, Louisville, Kentucky 40292.,University of Louisville Superfund Research Center, Louisville, Kentucky 40202
| | - Zhengzhi Xie
- Department of Medicine, Diabetes and Obesity Center, University of Louisville, Louisville, Kentucky 40292.,Envirome Institute, University of Louisville, Louisville, Kentucky 40292.,University of Louisville Superfund Research Center, Louisville, Kentucky 40202
| | - Aruni Bhatnagar
- Department of Medicine, Diabetes and Obesity Center, University of Louisville, Louisville, Kentucky 40292.,Envirome Institute, University of Louisville, Louisville, Kentucky 40292.,University of Louisville Superfund Research Center, Louisville, Kentucky 40202
| | - Sanjay Srivastava
- Department of Medicine, Diabetes and Obesity Center, University of Louisville, Louisville, Kentucky 40292.,Envirome Institute, University of Louisville, Louisville, Kentucky 40292.,University of Louisville Superfund Research Center, Louisville, Kentucky 40202
| | - Timothy E O'Toole
- Department of Medicine, Diabetes and Obesity Center, University of Louisville, Louisville, Kentucky 40292.,Envirome Institute, University of Louisville, Louisville, Kentucky 40292.,University of Louisville Superfund Research Center, Louisville, Kentucky 40202
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6
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Mi L, Sui J, Wu Y, Liang G, Zhang Y, Pu Y, Tian Y, Liu S, Jiang L. Bioinspired in Vitro Lung Airway Model for Inflammatory Analysis via Hydrophobic Nanochannel Membrane with Joint Three-Phase Interface. Anal Chem 2019; 91:15804-15810. [PMID: 31718146 DOI: 10.1021/acs.analchem.9b04114] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Because of the extremely low solubility of gas pollution, elucidating the pathogenetic mechanism between air pollution and the lung inflammatory response has remained a significant challenge. Here, we develop a bioinspired nanoporous membrane (BNM) with a three-phase interface as a gas exposure model that mimicks the airway mechanism, gas molecules contacting with alveolar cells directly, enabling high cell viability and sensitive inflammatory response analysis. Specifically, the top side of the porous anodic alumina (PAA) membrane was in contact with the medium for cell culture, and the bottom side contacted the gas phase directly for gas exposure. Compared with the two-phase interface, the viability of cells on the BNM was enhanced up to 3-fold. Additionally, results demonstrated that the inflammatory responses of cells stimulated by gas pollution (formaldehyde and benzene as models) from the gas phase were more obvious than those induced by gas pollution from solution, especially the increment of interleukin-2 (IL-2), IL-6, and tumor necrosis factor α (TNF-α), which was almost 2 times greater than that induced by gas pollution from solution. Furthermore, an enzyme inhibitor was introduced to evaluate potential applications of the BNM.
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Affiliation(s)
- Li Mi
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry , Beihang University , Beijing 100191 , China.,Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device, School of Chemistry and Chemical Engineering , Southeast University , Nanjing 211189 , China
| | - Jing Sui
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health , Southeast University , Nanjing 211189 , China
| | - Yafeng Wu
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device, School of Chemistry and Chemical Engineering , Southeast University , Nanjing 211189 , China
| | - Geyu Liang
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health , Southeast University , Nanjing 211189 , China
| | - Yuanjian Zhang
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device, School of Chemistry and Chemical Engineering , Southeast University , Nanjing 211189 , China
| | - Yuepu Pu
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health , Southeast University , Nanjing 211189 , China
| | - Ye Tian
- Key Laboratory of Bioinspired Smart Interface Sciences, Technical Institute of Physics and Chemistry , Chinese Academy of Sciences , Beijing 100190 , China
| | - Songqin Liu
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device, School of Chemistry and Chemical Engineering , Southeast University , Nanjing 211189 , China
| | - Lei Jiang
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry , Beihang University , Beijing 100191 , China.,Key Laboratory of Bioinspired Smart Interface Sciences, Technical Institute of Physics and Chemistry , Chinese Academy of Sciences , Beijing 100190 , China
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7
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Stoddard EG, Volk RF, Carson JP, Ljungberg CM, Murphree TA, Smith JN, Sadler NC, Shukla AK, Ansong C, Wright AT. Multifunctional Activity-Based Protein Profiling of the Developing Lung. J Proteome Res 2018; 17:2623-2634. [PMID: 29972024 DOI: 10.1021/acs.jproteome.8b00086] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Lung diseases and disorders are a leading cause of death among infants. Many of these diseases and disorders are caused by premature birth and underdeveloped lungs. In addition to developmentally related disorders, the lungs are exposed to a variety of environmental contaminants and xenobiotics upon birth that can cause breathing issues and are progenitors of cancer. In order to gain a deeper understanding of the developing lung, we applied an activity-based chemoproteomics approach for the functional characterization of the xenometabolizing cytochrome P450 enzymes, active ATP and nucleotide binding enzymes, and serine hydrolases using a suite of activity-based probes (ABPs). We detected P450 activity primarily in the postnatal lung; using our ATP-ABP, we characterized a wide range of ATPases and other active nucleotide- and nucleic acid-binding enzymes involved in multiple facets of cellular metabolism throughout development. ATP-ABP targets include kinases, phosphatases, NAD- and FAD-dependent enzymes, RNA/DNA helicases, and others. The serine hydrolase-targeting probe detected changes in the activities of several proteases during the course of lung development, yielding insights into protein turnover at different stages of development. Select activity-based probe targets were then correlated with RNA in situ hybridization analyses of lung tissue sections.
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Affiliation(s)
- Ethan G Stoddard
- Biological Sciences Division , Pacific Northwest National Laboratory , Richland , Washington 99352 , United States
| | - Regan F Volk
- Biological Sciences Division , Pacific Northwest National Laboratory , Richland , Washington 99352 , United States
| | - James P Carson
- Texas Advanced Computing Center , University of Texas at Austin , Austin , Texas 78758 , United States
| | - Cecilia M Ljungberg
- Department of Pediatrics, Baylor College of Medicine , Jan and Dan Duncan Neurological Research Center at Texas Children's Hospital , Houston , Texas 77030 , United States
| | - Taylor A Murphree
- Biological Sciences Division , Pacific Northwest National Laboratory , Richland , Washington 99352 , United States
| | - Jordan N Smith
- Biological Sciences Division , Pacific Northwest National Laboratory , Richland , Washington 99352 , United States
| | - Natalie C Sadler
- Biological Sciences Division , Pacific Northwest National Laboratory , Richland , Washington 99352 , United States
| | - Anil K Shukla
- Biological Sciences Division , Pacific Northwest National Laboratory , Richland , Washington 99352 , United States
| | - Charles Ansong
- Biological Sciences Division , Pacific Northwest National Laboratory , Richland , Washington 99352 , United States
| | - Aaron T Wright
- Biological Sciences Division , Pacific Northwest National Laboratory , Richland , Washington 99352 , United States.,The Gene and Linda Voiland School of Chemical Engineering and Bioengineering , Washington State University , Pullman , Washington 99163 , United States
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8
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Warden H, Richardson H, Richardson L, Siemiatycki J, Ho V. Associations between occupational exposure to benzene, toluene and xylene and risk of lung cancer in Montréal. Occup Environ Med 2018; 75:696-702. [PMID: 29764994 DOI: 10.1136/oemed-2017-104987] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Revised: 04/18/2018] [Accepted: 04/28/2018] [Indexed: 11/04/2022]
Abstract
BACKGROUND Benzene, toluene and xylene (BTX) are aromatic hydrocarbons with inconclusive evidence of lung carcinogenicity. The aim of this research was to assess the associations between occupational exposures to BTX agents and lung cancer. METHODS In a population-based case-control study of lung cancer, occupational histories were obtained and exposures were assessed by experts. Unconditional multivariate logistic regression was used to estimate ORs and 95% CIs, among men, between various metrics of occupational exposure to BTX and lung cancer, while adjusting for established and possible risk factors. RESULTS Considerable overlap was found between occupational exposure to BTX, where the majority of exposed participants were exposed to all three chemicals. Lung cancer was associated with exposure to benzene (OR=1.35; 95% CI 0.99 to 1.84), toluene (OR=1.31; 95% CI 0.99 to 1.74) and xylene (OR=1.44; 95% CI 1.03 to 2.01). While these results were adjusted for smoking and other recognised and possible lung cancer risk factors, they were not mutually adjusted among the three BTX agents. CONCLUSIONS Our study provides suggestive evidence that occupational exposure to one or more of the BTX agents may be associated with lung cancer.
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Affiliation(s)
- Hunter Warden
- Department of Public Health Sciences, Queen's University, Kingston, Ontario, Canada
| | - Harriet Richardson
- Department of Public Health Sciences, Queen's University, Kingston, Ontario, Canada
| | - Lesley Richardson
- University of Montréal Hospital Research Centre (CRCHUM), Health Innovation and Evaluation Hub, Montréal, Québec, Canada
| | - Jack Siemiatycki
- University of Montréal Hospital Research Centre (CRCHUM), Health Innovation and Evaluation Hub, Montréal, Québec, Canada.,Department of Social and Preventive Medicine, University of Montréal, Montréal, Québec, Canada
| | - Vikki Ho
- University of Montréal Hospital Research Centre (CRCHUM), Health Innovation and Evaluation Hub, Montréal, Québec, Canada.,Department of Social and Preventive Medicine, University of Montréal, Montréal, Québec, Canada
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9
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Han W, Wang S, Li M, Jiang L, Wang X, Xie K. The protective effect of diallyl trisulfide on cytopenia induced by benzene through modulating benzene metabolism. Food Chem Toxicol 2018; 112:393-399. [PMID: 29305270 DOI: 10.1016/j.fct.2017.12.060] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 12/24/2017] [Accepted: 12/28/2017] [Indexed: 02/02/2023]
Abstract
It has been known that metabolism of benzene is necessary for its toxicity. The purpose of our study is to investigate the effect of diallyl trisulfide (DATS) on attenuating cytopenia in peripheral blood introduced by benzene through regulating benzene metabolism in rats. We established benzene poisoning model with benzene (1.3 g/kg), while the DATS treatment groups were treated with DATS plus benzene (15 or 30 mg/kg) for 28 days, respectively. The results of blood parameters and concentration of metabolites of benzene (t, t-MA and SPMA) determination in urine showed that DATS could effectively attenuate the cytopenia induced by benzene through regulating benzene metabolism. Western blot and chemical method were used to detect the activities and protein expression levels of enzymes CYP2E1 and GSTT1 in liver and enzymes MPO and NQO1 in bone marrow were tested. The results suggested that the inhibition of bioactivation in liver and bone marrow catalyzed by CYP2E1 and MPO and the activation of detoxification catalyzed by GSTT1 and NQO1 might be the critical mechanism, through which DATS modulated benzene metabolism to prevent benzene-induced cytopenia.
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Affiliation(s)
- Wenting Han
- Institute of Toxicology, School of Public Health, Shandong University, Jinan, Shandong 250012, China; School of Food Engineering, Ludong University, Yantai, Shandong 264025, China.
| | - Shuo Wang
- Institute of Toxicology, School of Public Health, Shandong University, Jinan, Shandong 250012, China
| | - Ming Li
- Institute of Toxicology, School of Public Health, Shandong University, Jinan, Shandong 250012, China
| | - Lulu Jiang
- Institute of Toxicology, School of Public Health, Shandong University, Jinan, Shandong 250012, China
| | - Xujing Wang
- Institute of Toxicology, School of Public Health, Shandong University, Jinan, Shandong 250012, China
| | - Keqin Xie
- Institute of Toxicology, School of Public Health, Shandong University, Jinan, Shandong 250012, China.
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10
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McNally K, Sams C, Loizou GD, Jones K. Evidence for non-linear metabolism at low benzene exposures? A reanalysis of data. Chem Biol Interact 2017; 278:256-268. [PMID: 28899792 DOI: 10.1016/j.cbi.2017.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 08/30/2017] [Accepted: 09/01/2017] [Indexed: 12/17/2022]
Abstract
The presence of a high-affinity metabolic pathway for low level benzene exposures of less than one part per million (ppm) has been proposed although a pathway has not been identified. The variation of metabolite molar fractions with increasing air benzene concentrations was suggested as evidence of significantly more efficient benzene metabolism at concentrations <0.1 ppm The evidence for this pathway is predicated on a rich data set from a study of Chinese shoe workers exposed to a wide range of benzene concentrations (not just "low level"). In this work we undertake a further independent re-analysis of this data with a focus on the evidence for an increase in the rate of metabolism of benzene exposures of less than 1 ppm. The analysis dataset consisted of measurements of benzene and toluene from personal air samplers, and measurements of unmetabolised benzene and toluene and five metabolites (phenol hydroquinone, catechol, trans, trans-muconic acid and s-phenylmercapturic acid) from post-shift urine samples for 213 workers with an occupational exposure to benzene (and toluene) and 139 controls. Measurements from control subjects were used to estimate metabolite concentrations resulting from non-occupational sources, including environmental sources of benzene. Data from occupationally exposed subjects were used to estimate metabolite concentrations as a function of benzene exposure. Correction for background (environmental exposure) sources of metabolites was achieved through a comparison of geometric means in occupationally exposed and control populations. The molar fractions of the five metabolites as a function of benzene exposure were computed. A supra-linear relationship between metabolite concentrations and benzene exposure was observed over the range 0.1-10 ppm benzene, however over the range benzene exposures of between 0.1 and 1 ppm only a modest departure from linearity was observed. The molar fractions estimated in this work were near constant over the range 0.1-10 ppm. No evidence of high affinity metabolism at these low level exposures was observed. Our reanalysis brings in to question the appropriateness of the dataset for commenting on low dose exposures and the use of a purely statistical approach to the analysis.
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Affiliation(s)
- K McNally
- Health & Safety Laboratory, Harpur Hill, Buxton, SK17 9JN, UK
| | - C Sams
- Health & Safety Laboratory, Harpur Hill, Buxton, SK17 9JN, UK
| | - G D Loizou
- Health & Safety Laboratory, Harpur Hill, Buxton, SK17 9JN, UK
| | - K Jones
- Health & Safety Laboratory, Harpur Hill, Buxton, SK17 9JN, UK.
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11
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Al Zallouha M, Landkocz Y, Brunet J, Cousin R, Genty E, Courcot D, Siffert S, Shirali P, Billet S. Usefulness of toxicological validation of VOCs catalytic degradation by air-liquid interface exposure system. ENVIRONMENTAL RESEARCH 2017; 152:328-335. [PMID: 27837714 DOI: 10.1016/j.envres.2016.10.027] [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: 07/22/2016] [Revised: 10/24/2016] [Accepted: 10/27/2016] [Indexed: 06/06/2023]
Abstract
Toluene is one of the most used Volatile Organic Compounds (VOCs) in the industry despite its major health impacts. Catalytic oxidation represents an efficient remediation technique in order to reduce its emission directly at the source, but it can release by-products. To complete the classical performance assessment using dedicated analytical chemistry methods, we propose to perform an untargeted toxicological validation on two efficient catalysts. Using biological system allows integrating synergy and antagonism in toxic effects of emitted VOCs and by-products, often described in case of multi-exposure condition. Catalysts Pd/α-Al2O3 and Pd/γ-Al2O3 developed for the oxidation of toluene were both coupled to a Vitrocell® Air-Liquid Interface (ALI) system, for exposure of human A549 lung cells during 1h to toluene or to catalysts exhaust before quantification of xenobiotics metabolizing enzymes. This study validated initially the Vitrocell® as an innovative, direct and dynamic model of ALI exposure in the assessment of the performances of new catalysts, showing the presence of chemically undetected by-products. The comparison of the two catalysts showed then that fewer organic compounds metabolizing genes were induced by Pd/γ-Al2O3 in comparison to Pd/α-Al2O3, suggesting that Pd/γ-Al2O3 is more efficient for toluene total oxidation from a toxicological point of view.
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Affiliation(s)
- Margueritta Al Zallouha
- Unité de Chimie Environnementale et Interactions sur le Vivant EA4492, Université du Littoral Côte d'Opale, 189A Avenue Maurice Schumann, 59140 Dunkerque, France
| | - Yann Landkocz
- Unité de Chimie Environnementale et Interactions sur le Vivant EA4492, Université du Littoral Côte d'Opale, 189A Avenue Maurice Schumann, 59140 Dunkerque, France
| | - Julien Brunet
- Unité de Chimie Environnementale et Interactions sur le Vivant EA4492, Université du Littoral Côte d'Opale, 189A Avenue Maurice Schumann, 59140 Dunkerque, France
| | - Renaud Cousin
- Unité de Chimie Environnementale et Interactions sur le Vivant EA4492, Université du Littoral Côte d'Opale, 189A Avenue Maurice Schumann, 59140 Dunkerque, France
| | - Eric Genty
- Unité de Chimie Environnementale et Interactions sur le Vivant EA4492, Université du Littoral Côte d'Opale, 189A Avenue Maurice Schumann, 59140 Dunkerque, France
| | - Dominique Courcot
- Unité de Chimie Environnementale et Interactions sur le Vivant EA4492, Université du Littoral Côte d'Opale, 189A Avenue Maurice Schumann, 59140 Dunkerque, France
| | - Stéphane Siffert
- Unité de Chimie Environnementale et Interactions sur le Vivant EA4492, Université du Littoral Côte d'Opale, 189A Avenue Maurice Schumann, 59140 Dunkerque, France
| | - Pirouz Shirali
- Unité de Chimie Environnementale et Interactions sur le Vivant EA4492, Université du Littoral Côte d'Opale, 189A Avenue Maurice Schumann, 59140 Dunkerque, France
| | - Sylvain Billet
- Unité de Chimie Environnementale et Interactions sur le Vivant EA4492, Université du Littoral Côte d'Opale, 189A Avenue Maurice Schumann, 59140 Dunkerque, France.
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12
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Zarth AT, Murphy SE, Hecht SS. Benzene oxide is a substrate for glutathione S-transferases. Chem Biol Interact 2015; 242:390-5. [PMID: 26554337 PMCID: PMC4695229 DOI: 10.1016/j.cbi.2015.11.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 11/04/2015] [Indexed: 02/02/2023]
Abstract
Benzene is a known human carcinogen which must be activated to benzene oxide (BO) to exert its carcinogenic potential. BO can be detoxified in vivo by reaction with glutathione and excretion in the urine as S-phenylmercapturic acid. This process may be catalyzed by glutathione S-transferases (GSTs), but kinetic data for this reaction have not been published. Therefore, we incubated GSTA1, GSTT1, GSTM1, and GSTP1 with glutathione and BO and quantified the formation of S-phenylglutathione. Kinetic parameters were determined for GSTT1 and GSTP1. At 37 °C, the putative Km and Vmax values for GSTT1 were 420 μM and 450 fmol/s, respectively, while those for GSTP1 were 3600 μM and 3100 fmol/s. GSTA1 and GSTM1 did not exhibit sufficient activity for determination of kinetic parameters. We conclude that GSTT1 is a critical enzyme in the detoxification of BO and that GSTP1 may also play an important role, while GSTA1 and GSTM1 seem to be less important.
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Affiliation(s)
- Adam T Zarth
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA; Medicinal Chemistry Graduate Program, University of Minnesota, Minneapolis, MN, USA.
| | - Sharon E Murphy
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA; Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Stephen S Hecht
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA; Medicinal Chemistry Graduate Program, University of Minnesota, Minneapolis, MN, USA
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13
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De Palma G, Manno M. Metabolic polymorphisms and biomarkers of effect in the biomonitoring of occupational exposure to low-levels of benzene: state of the art. Toxicol Lett 2014; 231:194-204. [PMID: 25447454 DOI: 10.1016/j.toxlet.2014.10.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 10/07/2014] [Accepted: 10/09/2014] [Indexed: 12/21/2022]
Abstract
Current levels of occupational exposure to benzene, a genotoxic human carcinogen, in Western countries are reduced by two-three orders of magnitude (from ppm to ppb) as compared to the past. However, as benzene toxicity is strongly dependent on biotransformation and recent evidence underlines a higher efficiency of bio-activation pathways at lower levels of exposure, toxic effects at low doses could be higher than expected, particularly in susceptible individuals. Currently, biological monitoring can allow accurate exposure assessment, relying on sensitive and specific enough biomarkers of internal dose. The availability of similarly reliable biomarkers of early effect or susceptibility could greatly improve the risk assessment process to such an extent that risk could even be assessed at the individual level. As to susceptibility biomarkers, functional genetic polymorphisms of relevant biotransformation enzymes may modulate the risk of adverse effects (NQO1) and the levels of biomarkers of internal dose, in particular S-phenylmercapturic acid (GSTM1, GSTT1, GSTA1). Among biomarkers of early effect, genotoxicity indicators, although sensitive in some cases, are too aspecific for routine use in occupational health surveillance programmes. Currently only the periodical blood cell count seems suitable enough to be applied in the longitudinal monitoring of effects from benzene exposure. Novel biomarkers of early effect are expected from higher collaboration among toxicologists and clinicians, also using advanced "omics" techniques.
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Affiliation(s)
- G De Palma
- Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, Section of Public Health and Human Sciences, University of Brescia, Piazzale Spedali Civili 1, 25123 Brescia, Italy.
| | - M Manno
- Department of Public Health, Section of Occupational Medicine and Toxicology, University of Napoli Federico II, Via S. Pansini, 5, 80131 Napoli, Italy
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14
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Thomas R, Hubbard AE, McHale CM, Zhang L, Rappaport SM, Lan Q, Rothman N, Vermeulen R, Guyton KZ, Jinot J, Sonawane BR, Smith MT. Characterization of changes in gene expression and biochemical pathways at low levels of benzene exposure. PLoS One 2014; 9:e91828. [PMID: 24786086 PMCID: PMC4006721 DOI: 10.1371/journal.pone.0091828] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 02/14/2014] [Indexed: 11/19/2022] Open
Abstract
Benzene, a ubiquitous environmental pollutant, causes acute myeloid leukemia (AML). Recently, through transcriptome profiling of peripheral blood mononuclear cells (PBMC), we reported dose-dependent effects of benzene exposure on gene expression and biochemical pathways in 83 workers exposed across four airborne concentration ranges (from <1 ppm to >10 ppm) compared with 42 subjects with non-workplace ambient exposure levels. Here, we further characterize these dose-dependent effects with continuous benzene exposure in all 125 study subjects. We estimated air benzene exposure levels in the 42 environmentally-exposed subjects from their unmetabolized urinary benzene levels. We used a novel non-parametric, data-adaptive model selection method to estimate the change with dose in the expression of each gene. We describe non-parametric approaches to model pathway responses and used these to estimate the dose responses of the AML pathway and 4 other pathways of interest. The response patterns of majority of genes as captured by mean estimates of the first and second principal components of the dose-response for the five pathways and the profiles of 6 AML pathway response-representative genes (identified by clustering) exhibited similar apparent supra-linear responses. Responses at or below 0.1 ppm benzene were observed for altered expression of AML pathway genes and CYP2E1. Together, these data show that benzene alters disease-relevant pathways and genes in a dose-dependent manner, with effects apparent at doses as low as 100 ppb in air. Studies with extensive exposure assessment of subjects exposed in the low-dose range between 10 ppb and 1 ppm are needed to confirm these findings.
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Affiliation(s)
- Reuben Thomas
- Superfund Research Program, School of Public Health, University of California, Berkeley, California, United States of America
| | - Alan E. Hubbard
- Superfund Research Program, School of Public Health, University of California, Berkeley, California, United States of America
| | - Cliona M. McHale
- Superfund Research Program, School of Public Health, University of California, Berkeley, California, United States of America
| | - Luoping Zhang
- Superfund Research Program, School of Public Health, University of California, Berkeley, California, United States of America
| | - Stephen M. Rappaport
- Superfund Research Program, School of Public Health, University of California, Berkeley, California, United States of America
| | - Qing Lan
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Nathaniel Rothman
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Roel Vermeulen
- Institute of Risk assessment Sciences, Utrecht University, Utrecht, The Netherlands
| | - Kathryn Z. Guyton
- National Center for Environmental Assessment, Office of Research and Development, US EPA, Washington, DC, United States of America
| | - Jennifer Jinot
- National Center for Environmental Assessment, Office of Research and Development, US EPA, Washington, DC, United States of America
| | - Babasaheb R. Sonawane
- National Center for Environmental Assessment, Office of Research and Development, US EPA, Washington, DC, United States of America
| | - Martyn T. Smith
- Superfund Research Program, School of Public Health, University of California, Berkeley, California, United States of America
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15
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Arnold SM, Angerer J, Boogaard PJ, Hughes MF, O'Lone RB, Robison SH, Schnatter AR. The use of biomonitoring data in exposure and human health risk assessment: benzene case study. Crit Rev Toxicol 2013; 43:119-53. [PMID: 23346981 PMCID: PMC3585443 DOI: 10.3109/10408444.2012.756455] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Revised: 11/30/2012] [Accepted: 12/04/2012] [Indexed: 01/08/2023]
Abstract
Abstract A framework of "Common Criteria" (i.e. a series of questions) has been developed to inform the use and evaluation of biomonitoring data in the context of human exposure and risk assessment. The data-rich chemical benzene was selected for use in a case study to assess whether refinement of the Common Criteria framework was necessary, and to gain additional perspective on approaches for integrating biomonitoring data into a risk-based context. The available data for benzene satisfied most of the Common Criteria and allowed for a risk-based evaluation of the benzene biomonitoring data. In general, biomarker (blood benzene, urinary benzene and urinary S-phenylmercapturic acid) central tendency (i.e. mean, median and geometric mean) concentrations for non-smokers are at or below the predicted blood or urine concentrations that would correspond to exposure at the US Environmental Protection Agency reference concentration (30 µg/m(3)), but greater than blood or urine concentrations relating to the air concentration at the 1 × 10(-5) excess cancer risk (2.9 µg/m(3)). Smokers clearly have higher levels of benzene exposure, and biomarker levels of benzene for non-smokers are generally consistent with ambient air monitoring results. While some biomarkers of benzene are specific indicators of exposure, the interpretation of benzene biomonitoring levels in a health-risk context are complicated by issues associated with short half-lives and gaps in knowledge regarding the relationship between the biomarkers and subsequent toxic effects.
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16
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Abstract
Considerable support exists for the roles of metabolism in modulating the carcinogenic properties of chemicals. In particular, many of these compounds are pro-carcinogens that require activation to electrophilic forms to exert genotoxic effects. We systematically analyzed the existing literature on the metabolism of carcinogens by human enzymes, which has been developed largely in the past 25 years. The metabolism and especially bioactivation of carcinogens are dominated by cytochrome P450 enzymes (66% of bioactivations). Within this group, six P450s--1A1, 1A2, 1B1, 2A6, 2E1, and 3A4--accounted for 77% of the P450 activation reactions. The roles of these P450s can be compared with those estimated for drug metabolism and should be considered in issues involving enzyme induction, chemoprevention, molecular epidemiology, interindividual variations, and risk assessment.
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17
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Sankpal UT, Pius H, Khan M, Shukoor MI, Maliakal P, Lee CM, Abdelrahim M, Connelly SF, Basha R. Environmental factors in causing human cancers: emphasis on tumorigenesis. Tumour Biol 2012; 33:1265-74. [PMID: 22614680 DOI: 10.1007/s13277-012-0413-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 04/30/2012] [Indexed: 01/22/2023] Open
Abstract
The environment and dietary factors play an essential role in the etiology of cancer. Environmental component is implicated in ~80 % of all cancers; however, the causes for certain cancers are still unknown. The potential players associated with various cancers include chemicals, heavy metals, diet, radiation, and smoking. Lifestyle habits such as smoking and alcohol consumption, exposure to certain chemicals (e.g., polycyclic aromatic hydrocarbons, organochlorines), metals and pesticides also pose risk in causing human cancers. Several studies indicated a strong association of lung cancer with the exposure to tobacco products and asbestos. The contribution of excessive sunlight, radiation, occupational exposure (e.g., painting, coal, and certain metals) is also well established in cancer. Smoking, excessive alcohol intake, consumption of an unhealthy diet, and lack of physical activity can act as risk factors for cancer and also impact the prognosis. Even though the environmental disposition is linked to cancer, the level and duration of carcinogen-exposure and associated cellular and biochemical aspects determine the actual risk. Modulations in metabolism and DNA adduct formation are considered central mechanisms in environmental carcinogenesis. This review describes the major environmental contributors in causing cancer with an emphasis on molecular aspects associated with environmental disposition in carcinogenesis.
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Affiliation(s)
- Umesh T Sankpal
- Cancer Research Institute, MD Anderson Cancer Center Orlando, 6900 Lake Nona Blvd, Orlando, FL 32827, USA
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18
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Wei Y, Wu H, Li L, Liu Z, Zhou X, Zhang QY, Weng Y, D'Agostino J, Ling G, Zhang X, Kluetzman K, Yao Y, Ding X. Generation and characterization of a CYP2A13/2B6/2F1-transgenic mouse model. Drug Metab Dispos 2012; 40:1144-50. [PMID: 22397853 DOI: 10.1124/dmd.112.044826] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
CYP2A13, CYP2B6, and CYP2F1, which are encoded by neighboring cytochrome P450 genes on human chromosome 19, are active in the metabolic activation of many drugs, respiratory toxicants, and chemical carcinogens. To facilitate studies on the regulation and function of these human genes, we have generated a CYP2A13/2B6/2F1-transgenic (TG) mouse model (all *1 alleles). Homozygous transgenic mice are normal with respect to gross morphological features, development, and fertility. The tissue distribution of transgenic mRNA expression agreed well with the known respiratory tract-selective expression of CYP2A13 and CYP2F1 and hepatic expression of CYP2B6 in humans. CYP2A13 protein was detected through immunoblot analyses in the nasal mucosa (NM) (∼100 pmol/mg of microsomal protein; similar to the level of mouse CYP2A5) and the lung (∼0.2 pmol/mg of microsomal protein) but not in the liver of the TG mice. CYP2F1 protein, which could not be separated from mouse CYP2F2 in immunoblot analyses, was readily detected in the NM and lung but not the liver of TG/Cyp2f2-null mice, at levels 10- and 40-fold, respectively, lower than that of mouse CYP2F2 in the TG mice. CYP2B6 protein was detected in the liver (∼0.2 pmol/mg of microsomal protein) but not the NM or lung (with a detection limit of 0.04 pmol/mg of microsomal protein) of the TG mice. At least one transgenic protein (CYP2A13) seems to be active, because the NM of the TG mice had greater in vitro and in vivo activities in bioactivation of a CYP2A13 substrate, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (a lung carcinogen), than did the NM of wild-type mice.
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Affiliation(s)
- Yuan Wei
- Wadsworth Center, New York State Department of Health, Empire State Plaza, Box 509, Albany, NY 12201-0509, USA
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McHale CM, Zhang L, Smith MT. Current understanding of the mechanism of benzene-induced leukemia in humans: implications for risk assessment. Carcinogenesis 2012; 33:240-52. [PMID: 22166497 PMCID: PMC3271273 DOI: 10.1093/carcin/bgr297] [Citation(s) in RCA: 203] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 11/21/2011] [Accepted: 12/07/2011] [Indexed: 01/01/2023] Open
Abstract
Benzene causes acute myeloid leukemia and probably other hematological malignancies. As benzene also causes hematotoxicity even in workers exposed to levels below the US permissible occupational exposure limit of 1 part per million, further assessment of the health risks associated with its exposure, particularly at low levels, is needed. Here, we describe the probable mechanism by which benzene induces leukemia involving the targeting of critical genes and pathways through the induction of genetic, chromosomal or epigenetic abnormalities and genomic instability, in a hematopoietic stem cell (HSC); stromal cell dysregulation; apoptosis of HSCs and stromal cells and altered proliferation and differentiation of HSCs. These effects modulated by benzene-induced oxidative stress, aryl hydrocarbon receptor dysregulation and reduced immunosurveillance, lead to the generation of leukemic stem cells and subsequent clonal evolution to leukemia. A mode of action (MOA) approach to the risk assessment of benzene was recently proposed. This approach is limited, however, by the challenges of defining a simple stochastic MOA of benzene-induced leukemogenesis and of identifying relevant and quantifiable parameters associated with potential key events. An alternative risk assessment approach is the application of toxicogenomics and systems biology in human populations, animals and in vitro models of the HSC stem cell niche, exposed to a range of levels of benzene. These approaches will inform our understanding of the mechanisms of benzene toxicity and identify additional biomarkers of exposure, early effect and susceptibility useful for risk assessment.
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Affiliation(s)
| | | | - Martyn T. Smith
- Division of Environmental Health Sciences, Genes and Environment Laboratory, School of Public Health, University of California, Berkeley, CA 94720-7356, USA
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20
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Smith MT, Zhang L, McHale CM, Skibola CF, Rappaport SM. Benzene, the exposome and future investigations of leukemia etiology. Chem Biol Interact 2011; 192:155-9. [PMID: 21333640 PMCID: PMC3461963 DOI: 10.1016/j.cbi.2011.02.010] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Revised: 01/19/2011] [Accepted: 02/10/2011] [Indexed: 12/14/2022]
Abstract
Benzene exposure is associated with acute myeloid leukemia (AML), myelodysplastic syndromes (MDS), and probably lymphoma and childhood leukemia. Biological plausibility for a causal role of benzene in these diseases comes from its toxicity to hematopoietic stem cells (HSC) or progenitor cells, from which all leukemias and related disorders arise. The effect of this toxicity is manifest as lowered blood counts (hematotoxicity), even in individuals occupationally exposed to low levels of benzene. Benzene can induce AML/MDS via several well-characterized pathways associated with these diseases. Through its metabolites, benzene induces multiple alterations that likely contribute to the leukemogenic process, and appears to operate via multiple modes of action. To improve mechanistic understanding and for risk assessment purposes, it may be possible to measure several of the key events in these modes of action in an in vitro model of the bone marrow stem cell niche. Even though benzene is leukemogenic at relatively low occupational levels of exposure, it seems unlikely that it is a major cause of leukemia in the general population exposed to benzene in the ppb range. Other established non-genetic causes of AML, e.g. smoking, ionizing radiation and cancer chemotherapy, also only explain about 20% of AML incidence, leaving ∼80% unexplained. The question arises as to how to find the causes of the majority of de novo AMLs that remain unexplained. We propose that we should attempt to characterize the 'exposome' of human leukemia by using unbiased laboratory-based methods to find the unknown 'environmental' factors that contribute to leukemia etiology.
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Affiliation(s)
- Martyn T Smith
- Genes and Environment Laboratory, School of Public Health, University of California, Berkeley, CA 94720-7356, USA.
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21
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Rubio V, Zhang J, Valverde M, Rojas E, Shi ZZ. Essential role of Nrf2 in protection against hydroquinone- and benzoquinone-induced cytotoxicity. Toxicol In Vitro 2010; 25:521-9. [PMID: 21059386 DOI: 10.1016/j.tiv.2010.10.021] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Revised: 10/28/2010] [Accepted: 10/29/2010] [Indexed: 01/10/2023]
Abstract
Benzene is a well-established human carcinogen. Benzene metabolites hydroquinone (HQ) and benzoquinone (BQ) are highly reactive molecules capable of producing reactive oxygen species and causing oxidative stress. In this study, we investigated the role of the Nrf2, a key nuclear transcription factor that regulates antioxidant response element (ARE)-containing genes, in defense against HQ- and BQ-induced cytotoxicity in cultured human lung epithelial cells (Beas-2B). When the cells were exposed to HQ or BQ the activity of an ARE reporter was induced in a dose-dependent manner, meanwhile Nrf2 protein levels were elevated and accumulated in the nucleus. Increased expression of well-known Nrf2-dependent proteins including NQO1, GCLM, GSS and HMOX was also observed in the HQ/BQ-treated cells. Moreover, transient overexpression of Nrf2 conferred protection against HQ- and BQ-induced cell death, whereas knockdown of Nrf2 by small interfering RNA resulted in increased apoptosis. We also found that the increased susceptibility of Nrf2-knockdown cells to HQ and BQ was associated with reduced glutathione levels and loss of inducibility of ARE-driven genes, suggesting that deficiency of Nrf2 impairs cellular redox capacity to counteract oxidative damage. Altogether, these results suggest that Nrf2-ARE pathway is essential for protection against HQ- and BQ-induced toxicity.
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Affiliation(s)
- Valentina Rubio
- Departamento de Medicina Genómica y Toxicología Ambiental, Universidad Nacional Autónoma de México, México DF, Mexico
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22
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Abstract
Benzene is a ubiquitous chemical in our environment that causes acute leukemia and probably other hematological cancers. Evidence for an association with childhood leukemia is growing. Exposure to benzene can lead to multiple alterations that contribute to the leukemogenic process, indicating a multimodal mechanism of action. Research is needed to elucidate the different roles of multiple metabolites in benzene toxicity and the pathways that lead to their formation. Studies to date have identified a number of polymorphisms in candidate genes that confer susceptibility to benzene hematotoxicity. However, a genome-wide study is needed to truly assess the role of genetic variation in susceptibility. Benzene affects the blood-forming system at low levels of occupational exposure, and there is no evidence of a threshold. There is probably no safe level of exposure to benzene, and all exposures constitute some risk in a linear, if not supralinear, and additive fashion.
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Affiliation(s)
- Martyn T Smith
- Superfund Research Program, Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, California 94720-7356, USA.
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Tangjarukij C, Navasumrit P, Zelikoff JT, Ruchirawat M. The effects of pyridoxine deficiency and supplementation on hematological profiles, lymphocyte function, and hepatic cytochrome P450 in B6C3F1mice. J Immunotoxicol 2009; 6:147-60. [DOI: 10.1080/15476910903083866] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Rappaport SM, Kim S, Lan Q, Vermeulen R, Waidyanatha S, Zhang L, Li G, Yin S, Hayes RB, Rothman N, Smith MT. Evidence that humans metabolize benzene via two pathways. ENVIRONMENTAL HEALTH PERSPECTIVES 2009; 117:946-52. [PMID: 19590688 PMCID: PMC2702411 DOI: 10.1289/ehp.0800510] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Accepted: 02/18/2009] [Indexed: 05/07/2023]
Abstract
BACKGROUND Recent evidence has shown that humans metabolize benzene more efficiently at environmental air concentrations than at concentrations > 1 ppm. This led us to speculate that an unidentified metabolic pathway was mainly responsible for benzene metabolism at ambient levels. OBJECTIVE We statistically tested whether human metabolism of benzene is better fitted by a kinetic model having two pathways rather than one. METHODS We fit Michaelis-Menten-like models to levels of urinary benzene metabolites and the corresponding air concentrations for 263 nonsmoking Chinese females. Estimated benzene concentrations ranged from less than 0.001 ppm to 299 ppm, with 10th and 90th percentile values of 0.002 ppm and 8.97 ppm, respectively. RESULTS Using values of Akaike's information criterion obtained under the two models, we found strong statistical evidence favoring two metabolic pathways, with respective affinities (benzene air concentrations analogous to K(m) values) of 301 ppm for the low-affinity pathway (probably dominated by cytochrome P450 enzyme 2E1) and 0.594 ppm for the high-affinity pathway (unknown). The exposure-specific metabolite level predicted by our two-pathway model at nonsaturating concentrations was 184 muM/ppm of benzene, a value close to an independent estimate of 194 muM/ppm for a typical nonsmoking Chinese female. Our results indicate that a nonsmoking woman would metabolize about three times more benzene from the ambient environment under the two-pathway model (184 muM/ppm) than under the one-pathway model (68.6 muM/ppm). In fact, 73% of the ambient benzene dose would be metabolized via the unidentified high-affinity pathway. CONCLUSION Because regulatory risk assessments have assumed nonsaturating metabolism of benzene in persons exposed to air concentrations well above 10 ppm, our findings suggest that the true leukemia risks could be substantially greater than currently thought at ambient levels of exposure-about 3-fold higher among nonsmoking females in the general population.
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Affiliation(s)
- Stephen M Rappaport
- School of Public Health, University of California at Berkeley, Berkeley, California 94720-7356, USA.
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Wilbur S, Wohlers D, Paikoff S, Keith LS, Faroon O. ATSDR evaluation of health effects of benzene and relevance to public health. Toxicol Ind Health 2009; 24:263-398. [PMID: 19022880 DOI: 10.1177/0748233708090910] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
As part of its mandate, the Agency for Toxic Substances and Disease Registry (ATSDR) prepares toxicological profiles on hazardous chemicals found at Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) National Priorities List (NPL) sites that have the greatest public health impact. These profiles comprehensively summarize toxicological and environmental information. This article constitutes the release of portions of the Toxicological Profile for Benzene. The primary purpose of this article is to provide public health officials, physicians, toxicologists, and other interested individuals and groups with an overall perspective on the toxicology of benzene. It contains descriptions and evaluations of toxicological studies and epidemiological investigations and provides conclusions, where possible, on the relevance of toxicity and toxicokinetic data to public health.
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Affiliation(s)
- S Wilbur
- Agency for Toxic Substances and Disease Registry (ATSDR), U.S. Department of Health and Human Services, Atlanta, Georgia 30333, USA.
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Lewis D, Ito Y, Lake B. Molecular Modelling of CYP2F Substrates: Comparison of Naphthalene Metabolism by Human, Rat and Mouse CYP2F Subfamily Enzymes. ACTA ACUST UNITED AC 2009; 24:229-57. [DOI: 10.1515/dmdi.2009.24.2-4.229] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Dobrev ID, Nong A, Liao KH, Reddy MB, Plotzke KP, Andersen ME. Assessing Kinetic Determinants for Metabolism and Oral Uptake of Octamethylcyclotetrasiloxane (D4) from Inhalation Chamber Studies. Inhal Toxicol 2008; 20:361-73. [DOI: 10.1080/08958370801903743] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Edwards JE, Rose RL, Hodgson E. The metabolism of nonane, a JP-8 jet fuel component, by human liver microsomes, P450 isoforms and alcohol dehydrogenase and inhibition of human P450 isoforms by JP-8. Chem Biol Interact 2005; 151:203-11. [PMID: 15733541 DOI: 10.1016/j.cbi.2004.12.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/09/2004] [Indexed: 11/16/2022]
Abstract
Nonane, a component of jet-propulsion fuel 8 (JP-8), is metabolized to 2-nonanol and 2-nonanone by pooled human liver microsomes (pHLM). Cytochrome P450 (CYP) isoforms 1A2, 2B6 and 2E1 metabolize nonane to 2-nonanol, whereas alcohol dehydrogenase, CYPs 2B6 and 2E1 metabolize 2-nonanol to 2-nonanone. Nonane and 2-nonanol showed no significant effect on the metabolism of testosterone, estradiol or N,N-diethyl-m-toluamide (DEET), but did inhibit carbaryl metabolism. JP-8 showed modest inhibition of testosterone, estradiol and carbaryl metabolism, but had a more significant effect on the metabolism of DEET. JP-8 was shown to inhibit CYPs 1A2 and 2B6 mediated metabolism of DEET, suggesting that at least some of the components of JP-8 might be metabolized by CYPs 1A2and/or 2B6.
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Affiliation(s)
- Jeffrey E Edwards
- Environmental and Molecular Toxicology, North Carolina State University, Box 7633, Raleigh, NC 27695, USA
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Sheets P, Carlson G. Kinetic factors involved in the metabolism of benzene in mouse lung and liver. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2004; 67:421-430. [PMID: 14718178 DOI: 10.1080/15287390490273488] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Benzene is an occupational and environmental toxicant. The main human health concern associated with benzene exposure is acute myelogenous leukemia. Benzene produces lung tumors in mice, while its effects on human lung are not clear. The adverse effects of benzene are dependent on its metabolism by the cytochrome P-450 enzyme system. The isozymes CYP2E1 and CYP2F2 play roles in the metabolism of benzene at low, environmentally relevant concentrations. Previous studies indicate that the mouse lung readily metabolizes benzene and that CYP2F2 plays a role in this biotransformation. The significance of CYP2E1 and CYP2F2 in benzene metabolism was determined by measuring their apparent kinetic parameters K(m) and V(max). Use of wild-type and CYP2E1 knockout mice and selective inhibitors allowed the determination of the individual importance of both CYP2E1 and CYP2F2 in mouse liver and lung. A simple Michaelis-Menten relationship involving Lineweaver-Burk plots for the microsomal metabolism of benzene shows the apparent kinetic factors are different between the wild-type (K(m): 30.4 microM, V(max): 25.3 pmol/mg protein/min) and knockout (K(m): 1.9 microM, V(max): 0.5 pmol/mg protein/min) mouse livers. Wild-type lung has a K(m) of 2.3 microM and V(max) of 0.9 pmol/mg protein/min. CYP2E1 knockout lung has similar affinity and metabolic activity with a K(m) of 3.7 microM and V(max) of 1.2 pmol/mg protein/min. These data suggest CYP2E1 is less important in the lung than liver, and that it has a lower affinity for benzene but higher rate of hydroxylated metabolite production than does CYP2F2, which plays the predominant role in metabolizing benzene in mouse lung.
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Affiliation(s)
- Patrick Sheets
- School of Health Sciences, Purdue University, West Lafayette, Indiana 47907, USA
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Yoon BI, Hirabayashi Y, Kawasaki Y, Tsuboi I, Ott T, Kodama Y, Kanno J, Kim DY, Willecke K, Inoue T. Exacerbation of benzene pneumotoxicity in connexin 32 knockout mice: enhanced proliferation of CYP2E1-immunoreactive alveolar epithelial cells. Toxicology 2004; 195:19-29. [PMID: 14698565 DOI: 10.1016/j.tox.2003.08.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The pulmonary pathogenesis triggered by benzene exposure was studied. Since the role of the connexin 32 (Cx32) gap junction protein in mouse pulmonary pathogenesis has been suggested, in the present study, we explored a possible role of Cx32 in benzene-induced pulmonary pathogenesis using the wild-type (WT) and Cx32 knockout (KO) mice. The mice were exposed to 300 ppm benzene by inhalation for 6 h per day, 5 days per week for a total of 26 weeks, and then sacrificed to evaluate the pneumotoxicity or allowed to live out their life span to evaluate the reversibility of the lesions and tumor incidence. Our results clearly revealed exacerbated pneumotoxicity in the benzene-exposed Cx32 KO mice, characterized by diffuse granulomatous interstitial pneumonia, markedly increased mucin secretion of bronchial/bronchiolar and alveolar epithelial cells, and hyperplastic alveolar epithelial cells positive for CYP2E1. But the results did not indicate any enhancement of pulmonary tumorigenesis in the Cx32 KO mice though the number of animals was small.
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Affiliation(s)
- Byung-Il Yoon
- Division of Cellular and Molecular Toxicology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagayaku, Tokyo 158-8501, Japan
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Sheets PL, Yost GS, Carlson GP. Benzene metabolism in human lung cell lines BEAS-2B and A549 and cells overexpressing CYP2F1. J Biochem Mol Toxicol 2004; 18:92-9. [PMID: 15122651 DOI: 10.1002/jbt.20010] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Benzene is an occupational and environmental toxicant. The main human health concern associated with benzene exposure is leukemia. The toxic effects of benzene are dependent on its metabolism by the cytochrome p450 enzyme system. The cytochrome p450 enzymes CYP2E1 and CYP2F2 are the major contributors to the bioactivation of benzene in rats and mice. Although benzene metabolism has been shown to occur with mouse and human lung microsomal preparations, little is known about the ability of human CYP2F to metabolize benzene or the lung cell types that might activate this toxicant. Our studies compared bronchiolar derived (BEAS-2B) and alveolar derived (A549) human cell lines for benzene metabolizing ability by evaluating the roles of CYP2E1 and CYP2F1. BEAS-2B cells that overexpressed CYP2F1 and recombinant CYP2F1 were also evaluated. BEAS-2B cells overexpressing the enzyme CYP2F1 produced 47.4 +/- 14.7 pmols hydroxylated metabolite/10(6) cells/45 min. The use of the CYP2E1-selective inhibitor diethyldithiocarbamate and the CYP2F2-selective inhibitor 5-phenyl-1-pentyne demonstrated that both CYP2E1 and CYP2F1 are important in benzene metabolism in the BEAS-2B and A549 human lung cell lines. The recombinant expressed human CYP2F1 enzyme had a K(m) value of 3.83 microM and a V(max) value of 0.01 pmol/pmol p450 enzyme/min demonstrating a reasonably efficient catalysis of benzene metabolism (V(max)/K(m) = 2.6). Thus, these studies have demonstrated in human lung cell lines that benzene is bioactivated by two lung-expressed p450 enzymes.
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Affiliation(s)
- Patrick L Sheets
- School of Health Sciences, Purdue University, West Lafayette, IN 47907-2051, USA
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Lewis DFV, Bailey PT, Low LK. Molecular modelling of the mouse cytochrome P450 CYP2F2 based on the CYP102 crystal structure template and selective CYP2F2 substrate interactions. DRUG METABOLISM AND DRUG INTERACTIONS 2003; 19:97-113. [PMID: 12751909 DOI: 10.1515/dmdi.2002.19.2.97] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The results of homology modelling of the mouse cytochrome P450, CYP2F2, are reported, based on the CYP102 crystallographic template. It is found that selective CYP2F2 substrates are able to fit the putative active site of the enzyme via aromatic pi-pi stacking and, in some cases, hydrogen-bonded interactions. Two alkylnaphthalenes were investigated via the model to evaluate whether they are likely to act as CYP2F2 substrates and, of these, 2-isopropyl-naphthalene was found to fit the putative active site, whereas 2-(2-hexadecyl)naphthalene was unable to do this, due to its bulky side-chain. Consequently, it is possible to utilize homology modelling to evaluate the likelihood of enzyme-substrate selectivity for CYP2F2 and predict routes of metabolism mediated by this enzyme. This procedure can therefore be used to investigate the potential for activation of xenobiotics via this enzyme, especially those related to known CYP2F substrates, such as naphthalene.
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Affiliation(s)
- David F V Lewis
- School of Biomedical and Life Sciences, University of Surrey, Guildford, Surrey, UK.
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Carr BA, Wan J, Hines RN, Yost GS. Characterization of the human lung CYP2F1 gene and identification of a novel lung-specific binding motif. J Biol Chem 2003; 278:15473-83. [PMID: 12598524 DOI: 10.1074/jbc.m300319200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The CYP2F1 gene encodes a cytochrome P450 enzyme capable of bioactivating a number of pulmonary-selective toxicants. The expression of CYP2F1 is highly tissue-selective; the highest expression is observed in the lung with little or no hepatic expression. The objective of these studies was to elucidate the mechanisms that govern the unique tissue-specific regulation of CYP2F1. Cosmid and bacterial artificial chromosome clones were screened and sequenced to identify a gene that spanned 14 kbp containing 10 exons, including an untranslated exon 1. Primer extension analysis and 5'-rapid amplification of cDNA ends were used to identify the transcription start site. Several sequences homologous to known cis-elements were identified in the 5'-upstream region of the CYP2F1 promoter. Transient transfection studies with luciferase reporter constructs demonstrated a significant functional lung cell-specific CYP2F1 promoter region (from position -129 to +115). DNase footprinting analysis of 1.6 kbp of the upstream sequence with nuclear extracts from human lung tissues revealed one strong DNA-protein complex at -152 to -182. This nuclear protein (called lung-specific factor, LSF) was present only in lung but not liver or heart tissues. Competitive electrophoretic mobility shift assays characterized a DNA consensus site, within the LSF-binding domain, that was highly similar to two E box motifs, but no known "E box" trans-factors were identified. These studies identified a novel LSF and its consensus sequence that may control tissue-specific expression of CYP2F1.
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Affiliation(s)
- Brian A Carr
- Department of Pharmacology and Toxicology, University of Utah, 30 S. 2000 E., Salt Lake City, UT 84112, USA
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Abstract
This chapter is an update of the data on substrates, reactions, inducers, and inhibitors of human CYP enzymes published previously by Rendic and DiCarlo (1), now covering selection of the literature through 2001 in the reference section. The data are presented in a tabular form (Table 1) to provide a framework for predicting and interpreting the new P450 metabolic data. The data are formatted in an Excel format as most suitable for off-line searching and management of the Web-database. The data are presented as stated by the author(s) and in the case when several references are cited the data are presented according to the latest published information. The searchable database is available either as an Excel file (for information contact the author), or as a Web-searchable database (Human P450 Metabolism Database, www.gentest.com) enabling the readers easy and quick approach to the latest updates on human CYP metabolic reactions.
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Affiliation(s)
- Slobodan Rendic
- Faculty of Pharmacy and Biochemistry, University of Zagreb, Croatia.
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Abstract
Benzene is an occupational and environmental toxicant. The major health concern for humans is acute myelogenous leukemia. To exert its toxic effects, benzene must be metabolized via cytochrome P450. CYP2E1 has been identified as the most important cytochrome, P450 isozyme in hepatic benzene metabolism in mice, rats, and humans. In pulmonary microsomes CYP2E1 and members of the CYP2F subfamily are both significantly involved. In the current study CYP2E1 knockout mice and wild-type controls were used to further examine the cytochrome P450 isozymes involved in metabolism of 24 microM benzene. The results show that CYP2E1 is the most important isozyme in the liver, accounting for 96% of the total hydroxylated metabolite formation. However, in the lung CYP2E1 was responsible for only 45% of the formation of total hydroxylated metabolite. Chemical inhibitors of CYP2E1 and CYP2F2 were used to further examine the contributions of these isozymes to benzene metabolism. The results confirmed the finding that while CYP2E1 is the most important isozyme in the liver, CYP2F2 and CYP2E1 are both significantly involved in the lung.
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Affiliation(s)
- M W Powley
- School of Health Sciences, 1338 Civil Engineering Building, Purdue University, West Lafayette, IN 47907-1338, USA
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Powley MW, Carlson GP. Cytochrome P450 isozymes involved in the metabolism of phenol, a benzene metabolite. Toxicol Lett 2001; 125:117-23. [PMID: 11701230 DOI: 10.1016/s0378-4274(01)00441-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Benzene is an occupational and environmental toxicant. The major health concern for humans is acute myelogenous leukemia. To exert its toxic effects, benzene must be metabolized by cytochrome P450 to phenol and subsequently to catechol and hydroquinone. Previous research has implicated CYP2E1 in the metabolism of phenol. In this study the cytochrome P450 isozymes involved in the metabolism of phenol were examined in hepatic and pulmonary microsomes utilizing chemical inhibitors of CYP2E1, CYP2B, and CYP2F2 and using CYP2E1 knockout mice. CYP2E1 was found to be responsible for only approximately 50% of 20 microM phenol metabolism in the liver. This suggests another isozyme(s) is involved in hepatic phenol metabolism. In pulmonary microsomes both CYP2E1 and CYP2F2 were significantly involved.
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Affiliation(s)
- M W Powley
- School of Health Sciences, Purdue University, 1338 Civil Engineering Building, West Lafayette, IN 47907-1338, USA
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