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Kobets T, Smith BPC, Williams GM. Food-Borne Chemical Carcinogens and the Evidence for Human Cancer Risk. Foods 2022; 11:2828. [PMID: 36140952 PMCID: PMC9497933 DOI: 10.3390/foods11182828] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 09/07/2022] [Accepted: 09/08/2022] [Indexed: 11/16/2022] Open
Abstract
Commonly consumed foods and beverages can contain chemicals with reported carcinogenic activity in rodent models. Moreover, exposures to some of these substances have been associated with increased cancer risks in humans. Food-borne carcinogens span a range of chemical classes and can arise from natural or anthropogenic sources, as well as form endogenously. Important considerations include the mechanism(s) of action (MoA), their relevance to human biology, and the level of exposure in diet. The MoAs of carcinogens have been classified as either DNA-reactive (genotoxic), involving covalent reaction with nuclear DNA, or epigenetic, involving molecular and cellular effects other than DNA reactivity. Carcinogens are generally present in food at low levels, resulting in low daily intakes, although there are some exceptions. Carcinogens of the DNA-reactive type produce effects at lower dosages than epigenetic carcinogens. Several food-related DNA-reactive carcinogens, including aflatoxins, aristolochic acid, benzene, benzo[a]pyrene and ethylene oxide, are recognized by the International Agency for Research on Cancer (IARC) as causes of human cancer. Of the epigenetic type, the only carcinogen considered to be associated with increased cancer in humans, although not from low-level food exposure, is dioxin (TCDD). Thus, DNA-reactive carcinogens in food represent a much greater risk than epigenetic carcinogens.
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Affiliation(s)
- Tetyana Kobets
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, NY 10595, USA
| | - Benjamin P. C. Smith
- Future Ready Food Safety Hub, Nanyang Technological University, Singapore 639798, Singapore
| | - Gary M. Williams
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, NY 10595, USA
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Zayed A, Sobeh M, Farag MA. Dissecting dietary and semisynthetic volatile phenylpropenes: A compile of their distribution, food properties, health effects, metabolism and toxicities. Crit Rev Food Sci Nutr 2022; 63:11105-11124. [PMID: 35708064 DOI: 10.1080/10408398.2022.2087175] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Phenylpropenes represent a major subclass of plant volatiles, including eugenol, and (E)-anethole. They contribute to the flavor and aroma of many chief herbs and spices, to exert distinct notes in food, i.e., spicy anise- and clove-like to fruit. Asides from their culinary use, they appear to exert general health effects, whereas some effects are specific, e.g., eugenol being a natural local anesthetic. This review represents the most comprehensive overview of phenylpropenes with respect to their chemical structures, different health effects, and their food applications as flavor and food preservatives. Side effects and toxicities of these compounds represent the second main part of this review, as some were reported for certain metabolites generated inside the body. Several metabolic reactions mediating for phenylpropenes metabolism in rodents via cytochrome P450 (CYP450) and sulfotransferase (SULT) enzymes are presented being involved in their toxicities. Such effects can be lessened by influencing their pharmacokinetics through a matrix-derived combination effect via administration of herbal extracts containing SULT inhibitors, i.e., nevadensin in sweet basil. Moreover, structural modification of phenylpropanes appears to improve their effects and broaden their applications. Hence, such review capitalizing on phenylpropenes can help optimize their applications in nutraceuticals, cosmeceuticals, and food applications.
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Affiliation(s)
- Ahmed Zayed
- Pharmacognosy Department, College of Pharmacy, Tanta University, Tanta, Egypt
- Institute of Bioprocess Engineering, Technical University of Kaiserslautern, Kaiserslautern, Germany
| | - Mansour Sobeh
- AgroBioSciences, Mohammed VI Polytechnic University, Ben-Guerir, Morocco
| | - Mohamed A Farag
- Pharmacognosy Department, College of Pharmacy, Cairo University, Cairo, Egypt
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3
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Giri S, Barhoi D, Nath Barbhuiya S, Giri A, Das S, Das A, Devi SH, Talukdar D, Upadhaya P, Langthasa P, Pandey N, Singh S. Consumption pattern and genotoxic potential of various smokeless tobacco products in Assam, India: A public health concern. Mutat Res 2021; 866:503349. [PMID: 33985693 DOI: 10.1016/j.mrgentox.2021.503349] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 03/02/2021] [Accepted: 03/12/2021] [Indexed: 01/23/2023]
Abstract
Smokeless tobacco (SLT) consumption is presumed to be one of the major causes of high incidence of oral cancer in India. The present study aimed to document various types of SLT products consumed and their potential impact on the genome instability on the population from Assam state in Northeast India. A cross-sectional study (n = 5000) showed that 60.56 % of the study population consumed at least one of the three forms (sadagura, zarda and khaini) of SLT of which 52.0 % were only sadagura users. Genotoxicity assessment using buccal cytome assay in 240 age and sex matched volunteers revealed that except for zarda, other forms of SLT induced significantly higher incidence micronuclei in the buccal epithelial cells compared to the control individuals. Similar effects were also observed in other cytome parameters related to cell proliferation, cytokinesis defects and cell death. Significantly higher incidence of micronucleus was observed among sadagura and khaini users in lymphocyte cytokinesis-blocked micronucleus assay. The addition of lime in sadagura increased the pH and anion levels which possibly result in higher absorption and may lead to the development of cellular anomalies.
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Affiliation(s)
- Sarbani Giri
- Molecular and Cell Biology Laboratory, Department of Life Science and Bioinformatics, Assam University, Silchar, 788011, India.
| | - Dharmeswar Barhoi
- Molecular and Cell Biology Laboratory, Department of Life Science and Bioinformatics, Assam University, Silchar, 788011, India.
| | - Sweety Nath Barbhuiya
- Molecular and Cell Biology Laboratory, Department of Life Science and Bioinformatics, Assam University, Silchar, 788011, India.
| | - Anirudha Giri
- Laboratory of Environmental and Human Toxicology, Department of Life Science and Bioinformatics, Assam University, Silchar, 788011, India.
| | - Samrat Das
- Molecular and Cell Biology Laboratory, Department of Life Science and Bioinformatics, Assam University, Silchar, 788011, India.
| | - Aparajita Das
- Molecular and Cell Biology Laboratory, Department of Life Science and Bioinformatics, Assam University, Silchar, 788011, India.
| | - Salam Himika Devi
- Molecular and Cell Biology Laboratory, Department of Life Science and Bioinformatics, Assam University, Silchar, 788011, India.
| | - Doli Talukdar
- Molecular and Cell Biology Laboratory, Department of Life Science and Bioinformatics, Assam University, Silchar, 788011, India.
| | - Puja Upadhaya
- Molecular and Cell Biology Laboratory, Department of Life Science and Bioinformatics, Assam University, Silchar, 788011, India.
| | - Pimily Langthasa
- Molecular and Cell Biology Laboratory, Department of Life Science and Bioinformatics, Assam University, Silchar, 788011, India.
| | - Neelam Pandey
- Molecular and Cell Biology Laboratory, Department of Life Science and Bioinformatics, Assam University, Silchar, 788011, India.
| | - Supriya Singh
- Molecular and Cell Biology Laboratory, Department of Life Science and Bioinformatics, Assam University, Silchar, 788011, India.
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4
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Collins A, Vettorazzi A, Azqueta A. The role of the enzyme-modified comet assay in in vivo studies. Toxicol Lett 2020; 327:58-68. [PMID: 32247831 DOI: 10.1016/j.toxlet.2020.03.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 03/18/2020] [Accepted: 03/20/2020] [Indexed: 12/24/2022]
Abstract
The in vivo comet assay is an established genotoxicity test, with an OECD test guideline, but in its standard form it measures only DNA strand breaks. Including in the assay an additional step, in which the DNA is incubated with a lesion-specific enzyme, can provide important information about the nature of the DNA damage. Formamidopyrimidine DNA glycosylase, 8-oxoguanine DNA glycosylase or endonuclease III are commonly used in the in vitro genotoxicity test and in human biomonitoring to detect oxidised bases, but in vivo applications are rarer. A systematic literature search has identified a total of 60 papers that report such in vivo experiments, testing a variety of agents. In many cases, strand breaks were not seen, but significant levels of enzyme-sensitive sites were induced - indicating a mechanism of action involving oxidative stress. Compounds such as methyl methanesulfonate (MMS) or ethyl methanesulfonate (EMS) could be used as positive controls in both the standard and the enzyme-modified in vivo comet assays.
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Affiliation(s)
- Andrew Collins
- Department of Nutrition, Institute for Basic Medical Sciences, University of Oslo, Sognsvannsveien 9, 0372, Oslo, Norway
| | - Ariane Vettorazzi
- Department of Pharmacology and Toxicology, University of Navarra, C/Irunlarrea 1, 31009, Pamplona, Spain; IdiSNA, Navarra Institute for Health Research, Spain
| | - Amaya Azqueta
- Department of Pharmacology and Toxicology, University of Navarra, C/Irunlarrea 1, 31009, Pamplona, Spain.
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Gooderham NJ, Cohen SM, Eisenbrand G, Fukushima S, Guengerich FP, Hecht SS, Rietjens IMCM, Rosol TJ, Bastaki M, Linman MJ, Taylor SV. The safety evaluation of food flavoring substances: the role of genotoxicity studies. Crit Rev Toxicol 2020; 50:1-27. [PMID: 32162576 DOI: 10.1080/10408444.2020.1712589] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The Flavor and Extract Manufacturers Association (FEMA) Expert Panel relies on the weight of evidence from all available data in the safety evaluation of flavoring substances. This process includes data from genotoxicity studies designed to assess the potential of a chemical agent to react with DNA or otherwise cause changes to DNA, either in vitro or in vivo. The Panel has reviewed a large number of in vitro and in vivo genotoxicity studies during the course of its ongoing safety evaluations of flavorings. The adherence of genotoxicity studies to standardized protocols and guidelines, the biological relevance of the results from those studies, and the human relevance of these studies are all important considerations in assessing whether the results raise specific concerns for genotoxic potential. The Panel evaluates genotoxicity studies not only for evidence of genotoxicity hazard, but also for the probability of risk to the consumer in the context of exposure from their use as flavoring substances. The majority of flavoring substances have given no indication of genotoxic potential in studies evaluated by the FEMA Expert Panel. Examples illustrating the assessment of genotoxicity data for flavoring substances and the consideration of the factors noted above are provided. The weight of evidence approach adopted by the FEMA Expert Panel leads to a rational assessment of risk associated with consumer intake of flavoring substances under the conditions of use.
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Affiliation(s)
| | - Samuel M Cohen
- Havlik-Wall Professor of Oncology, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Gerhard Eisenbrand
- Food Chemistry & Toxicology, University of Kaiserslautern (retired), Heidelberg, Germany
| | | | - F Peter Guengerich
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Stephen S Hecht
- Masonic Cancer Center and Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, USA
| | | | - Thomas J Rosol
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, USA
| | - Maria Bastaki
- Flavor and Extract Manufacturers Association, Washington, DC, USA
| | - Matthew J Linman
- Flavor and Extract Manufacturers Association, Washington, DC, USA
| | - Sean V Taylor
- Flavor and Extract Manufacturers Association, Washington, DC, USA
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6
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Das S, Upadhaya P, Barhoi D, Nath Barbhuiya S, Langthasa P, Giri S. GCMS analysis of sadagura (smokeless tobacco), its enhanced genomic instability causing potential due to arsenic co-exposure, and vitamin-C supplementation as a possible remedial measure: a study involving multiple model test systems. Drug Chem Toxicol 2019; 45:185-196. [DOI: 10.1080/01480545.2019.1675687] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Samrat Das
- Department of Life Science and Bioinformatics, Molecular and Cell Biology Laboratory, Assam University, Silchar, India
| | - Puja Upadhaya
- Department of Life Science and Bioinformatics, Molecular and Cell Biology Laboratory, Assam University, Silchar, India
| | - Dharmeswar Barhoi
- Department of Life Science and Bioinformatics, Molecular and Cell Biology Laboratory, Assam University, Silchar, India
| | - Sweety Nath Barbhuiya
- Department of Life Science and Bioinformatics, Molecular and Cell Biology Laboratory, Assam University, Silchar, India
| | - Pimily Langthasa
- Department of Life Science and Bioinformatics, Molecular and Cell Biology Laboratory, Assam University, Silchar, India
| | - Sarbani Giri
- Department of Life Science and Bioinformatics, Molecular and Cell Biology Laboratory, Assam University, Silchar, India
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Monick S, Mohanty V, Khan M, Yerneni G, Kumar R, Cantu J, Ichi S, Xi G, Singh BR, Tomita T, Mayanil CS. A Phenotypic Switch of Differentiated Glial Cells to Dedifferentiated Cells Is Regulated by Folate Receptor α. Stem Cells 2019; 37:1441-1454. [PMID: 31381815 PMCID: PMC6899875 DOI: 10.1002/stem.3067] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 07/05/2019] [Accepted: 07/09/2019] [Indexed: 12/18/2022]
Abstract
In a previous study, we showed that folate receptor‐α (FRα) translocates to the nucleus where it acts as a transcription factor and upregulates Hes1, Oct4, Sox2, and Klf4 genes responsible for pluripotency. Here, we show that acetylation and phosphorylation of FRα favor its nuclear translocation in the presence of folate and can cause a phenotypic switch from differentiated glial cells to dedifferentiated cells. shRNA‐FRα mediated knockdown of FRα was used to confirm the role of FRα in dedifferentiation. Ocimum sanctum hydrophilic fraction‐1 treatment not only blocks the folate mediated dedifferentiation of glial cells but also promotes redifferentiation of dedifferentiated glial cells, possibly by reducing the nuclear translocation of ~38 kDa FRα and subsequent interaction with chromatin assembly factor‐1. stem cells2019;37:1441–1454
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Affiliation(s)
- Sarah Monick
- Developmental Biology Program, Stanley Manne Children's Research Institute, Division of Pediatric Neurosurgery, Ann & Robert H. Lurie Children's Hospital of Chicago and Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Vineet Mohanty
- Developmental Biology Program, Stanley Manne Children's Research Institute, Division of Pediatric Neurosurgery, Ann & Robert H. Lurie Children's Hospital of Chicago and Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Mariam Khan
- Developmental Biology Program, Stanley Manne Children's Research Institute, Division of Pediatric Neurosurgery, Ann & Robert H. Lurie Children's Hospital of Chicago and Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Gowtham Yerneni
- Developmental Biology Program, Stanley Manne Children's Research Institute, Division of Pediatric Neurosurgery, Ann & Robert H. Lurie Children's Hospital of Chicago and Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Raj Kumar
- Institute of Advanced Sciences, Dartmouth, Massachusetts, USA
| | - Jorge Cantu
- Department of Biology, Northeastern Illinois University, Chicago, Illinois, USA
| | - Shunsuke Ichi
- Department of Neurosurgery, Japanese Red Cross Medical Center, Tokyo, Japan
| | - Guifa Xi
- Developmental Biology Program, Stanley Manne Children's Research Institute, Division of Pediatric Neurosurgery, Ann & Robert H. Lurie Children's Hospital of Chicago and Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Bal Ram Singh
- Institute of Advanced Sciences, Dartmouth, Massachusetts, USA
| | - Tadanori Tomita
- Developmental Biology Program, Stanley Manne Children's Research Institute, Division of Pediatric Neurosurgery, Ann & Robert H. Lurie Children's Hospital of Chicago and Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Chandra Shekhar Mayanil
- Developmental Biology Program, Stanley Manne Children's Research Institute, Division of Pediatric Neurosurgery, Ann & Robert H. Lurie Children's Hospital of Chicago and Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.,Institute of Advanced Sciences, Dartmouth, Massachusetts, USA
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8
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Abstract
BACKGROUND Methods for inference and comparison of biological networks are emerging as powerful tools for the identification of groups of tightly connected genes whose activity may be altered during disease progression or due to chemical perturbations. Connectivity-based comparisons help identify aggregate changes that would be difficult to detect with differential analysis methods comparing individual genes. METHODS In this study, we describe a pipeline for network comparison and its application to the analysis of gene expression datasets from chemical perturbation experiments, with the goal of elucidating the modes of actions of the profiled perturbations. We apply our pipeline to the analysis of the DrugMatrix and the TG-GATEs, two of the largest toxicogenomics resources available, containing gene expression measurements for model organisms exposed to hundreds of chemical compounds with varying carcinogenicity and genotoxicity. RESULTS Starting from chemical-specific transcriptional networks inferred from these data, we show that the proposed comparative analysis of their associated networks identifies groups of chemicals with similar functions and similar carcinogenicity/genotoxicity profiles. We also show that the in-silico annotation by pathway enrichment analysis of the gene modules with a significant gain or loss of connectivity for specific groups of compounds can reveal molecular pathways significantly associated with the chemical perturbations and their likely modes of action. CONCLUSIONS The proposed pipeline for transcriptional network inference and comparison is highly reproducible and allows grouping chemicals with similar functions and carcinogenicity/genotoxicity profiles. In the context of drug discovery or drug repositioning, the methods presented here could help assign new functions to novel or existing drugs, based on the similarity of their associated network with those built for other known compounds. Additionally, the method has broad applicability beyond the uses here described and could be used as an alternative or as a complement to standard approaches of differential gene expression analysis.
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9
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Sakita JY, Gasparotto B, Garcia SB, Uyemura SA, Kannen V. A critical discussion on diet, genomic mutations and repair mechanisms in colon carcinogenesis. Toxicol Lett 2017; 265:106-116. [DOI: 10.1016/j.toxlet.2016.11.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 11/09/2016] [Accepted: 11/27/2016] [Indexed: 02/07/2023]
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Ding W, Bishop ME, Lyn-Cook LE, Davis KJ, Manjanatha MG. In Vivo Alkaline Comet Assay and Enzyme-modified Alkaline Comet Assay for Measuring DNA Strand Breaks and Oxidative DNA Damage in Rat Liver. J Vis Exp 2016:53833. [PMID: 27166647 PMCID: PMC4942029 DOI: 10.3791/53833] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Unrepaired DNA damage can lead to genetic instability, which in turn may enhance cancer development. Therefore, identifying potential DNA damaging agents is important for protecting public health. The in vivo alkaline comet assay, which detects DNA damage as strand breaks, is especially relevant for assessing the genotoxic hazards of xenobiotics, as its responses reflect the in vivo absorption, tissue distribution, metabolism and excretion (ADME) of chemicals, as well as DNA repair process. Compared to other in vivo DNA damage assays, the assay is rapid, sensitive, visual and inexpensive, and, by converting oxidative DNA damage into strand breaks using specific repair enzymes, the assay can measure oxidative DNA damage in an efficient and relatively artifact-free manner. Measurement of DNA damage with the comet assay can be performed using both acute and subchronic toxicology study designs, and by integrating the comet assay with other toxicological assessments, the assay addresses animal welfare requirements by making maximum use of animal resources. Another major advantage of the assays is that they only require a small amount of cells, and the cells do not have to be derived from proliferating cell populations. The assays also can be performed with a variety of human samples obtained from clinically or occupationally exposed individuals.
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Affiliation(s)
- Wei Ding
- Division of Genetic and Molecular Toxicology, US FDA/National Center for Toxicological Research;
| | - Michelle E Bishop
- Division of Genetic and Molecular Toxicology, US FDA/National Center for Toxicological Research
| | - Lascelles E Lyn-Cook
- Division of Genetic and Molecular Toxicology, US FDA/National Center for Toxicological Research
| | - Kelly J Davis
- Toxicologic Pathology Associates, US FDA/National Center for Toxicological Research
| | - Mugimane G Manjanatha
- Division of Genetic and Molecular Toxicology, US FDA/National Center for Toxicological Research
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11
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Kobets T, Duan JD, Brunnemann KD, Etter S, Smith B, Williams GM. Structure-Activity Relationships for DNA Damage by Alkenylbenzenes in Turkey Egg Fetal Liver. Toxicol Sci 2015; 150:301-11. [DOI: 10.1093/toxsci/kfv322] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
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12
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Probert PM, Palmer JM, Alhusainy W, Amer AO, Rietjens IMCM, White SA, Jones DE, Wright MC. Progenitor-derived hepatocyte-like (B-13/H) cells metabolise 1'-hydroxyestragole to a genotoxic species via a SULT2B1-dependent mechanism. Toxicol Lett 2015; 243:98-110. [PMID: 26739637 PMCID: PMC4729325 DOI: 10.1016/j.toxlet.2015.12.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 12/23/2015] [Accepted: 12/23/2015] [Indexed: 01/24/2023]
Abstract
Rat B-13 progenitor cells are readily converted into functional hepatocyte-like B-13/H cells capable of phase I cytochrome P450-dependent activation of pro-carcinogens and induction of DNA damage. The aim of the present study was to investigate whether the cells are also capable of Phase II sulphotransferase (SULT)-dependent activation of a pro-carcinogen to an ultimate carcinogen. To this end we therefore examined the bioactivation of the model hepatic (hepato- and cholangio-) carcinogen estragole and its proximate SULT1A1-activated genotoxic metabolite 1'-hydroxyestragole. Exposing B-13 or B-13/H cells to estragole (at concentrations up to 1mM) resulted in the production of low levels of 1'-hydroxyestragole, but did not result in detectable DNA damage. Exposing B-13/H cells - but not B-13 cells - to 1'-hydroxyestragole resulted in a dose-dependent increase in DNA damage in comet assays, confirmed by detection of N(2)-(trans-isoestragol-3'-yl)-2'-deoxyguanosine adducts. Genotoxicity was inhibited by general SULT inhibitors, supporting a role for SULTS in the activation of 1-hydroxyestragole in B-13/H cells. However, B-13 and B-13/H cells did not express biologically significant levels of SULT1A1 as determined by qRT-PCR, Western blotting and its associated 7-hydroxycoumarin sulphation activity. B-13 and B-13/H cells expressed - relative to intact rat liver - high levels of SULT2B1 (primarily the b isoform) and SULT4A1 mRNAs and proteins. B-13 and B-13/H cells also expressed the 3'-phosphoadenosine 5'-phosphosulphate synthase 1 required for the generation of activated sulphate cofactor 3'-phosphoadenosine 5'-phosphosulphate. However, only B-13/H cells expressed functional SULT activities towards SULT2B1 substrates DHEA, pregnenolone and 4 methylumbelliferone. Since liver progenitor cells are bi-potential and also form cholangiocytes, we therefore hypothesised that B-13 cells express a cholangiocyte-like SULT profile. To test this hypothesis, the expression of SULTs was examined in liver by RT-PCR and immunohistochemistry. SULT2B1 - but not SULT1A1 - was determined to be expressed in both rat and human cholangiocytes. Since 1'-hydroxyestragole exposure readily produced DNA injury in B-13/H cells, these data suggest that cholangiocarcinomas generated in rats fed estragole may be dependent, in part, on SULT2B1 activation of the 1'-hydroxyestragole metabolite.
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Affiliation(s)
- Philip M Probert
- Institute Cellular Medicine, Newcastle University, Newcastle Upon Tyne, United Kingdom
| | - Jeremy M Palmer
- Institute Cellular Medicine, Newcastle University, Newcastle Upon Tyne, United Kingdom
| | - Wasma Alhusainy
- Division of Toxicology, Wageningen University, Tuinlaan 5, 6703HE Wageningen, The Netherlands
| | - Aimen O Amer
- Institute Cellular Medicine, Newcastle University, Newcastle Upon Tyne, United Kingdom
| | - Ivonne M C M Rietjens
- Division of Toxicology, Wageningen University, Tuinlaan 5, 6703HE Wageningen, The Netherlands
| | - Steven A White
- Institute Cellular Medicine, Newcastle University, Newcastle Upon Tyne, United Kingdom
| | - David E Jones
- Institute Cellular Medicine, Newcastle University, Newcastle Upon Tyne, United Kingdom
| | - Matthew C Wright
- Institute Cellular Medicine, Newcastle University, Newcastle Upon Tyne, United Kingdom.
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