1
|
Kobets T, Hickey C, Johnson G, Duan JD, Etter S, Smith B, Williams GM. Assessment of no-observed-effect-levels for DNA adducts formation by genotoxic carcinogens in fetal turkey livers. Toxicology 2024; 501:153714. [PMID: 38141718 DOI: 10.1016/j.tox.2023.153714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 12/08/2023] [Accepted: 12/18/2023] [Indexed: 12/25/2023]
Abstract
For genotoxic carcinogens, covalent binding to DNA is a critical initiating event in tumorigenesis. The present research investigated dose-effect relationships of three genotoxic carcinogens representing different structural classes, 2-acetylaminofluorene (2-AAF), benzo[a]pyrene (B[a]P) and quinoline (QUI), to assess the existence of no-observed-effect-levels (NOELs) for the formation of DNA adducts. Carcinogens were administered into the air sac of fertilized turkey eggs over wide dose ranges in three daily injections on days 22 to 24 of incubation. DNA adducts were measured in the fetal turkey livers by the 32P-nucleotide postlabeling (NPL) assay. B[a]P and QUI produced DNA adducts in a dosage-related manner and exhibited NOELs at 0.65 and 0.35 mg/kg bw/day, respectively. In contrast, 2-AAF formed DNA adducts at all tested dosages down to 0.005 mg/kg bw/day. Benchmark dose (BMD) analysis identified the potencies of 2-AAF and QUI to be similar, while B[a]P was the least potent compound. Overall, findings in fetal turkey livers demonstrated that exposure levels to genotoxic compounds that do not result in DNA adducts can exist but are not evident with all carcinogens of this type. The use of mechanistic dose-effect studies for genotoxic endpoints can provide critical information for prioritization of concerns for risk assessment.
Collapse
Affiliation(s)
- Tetyana Kobets
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, NY 10595, USA.
| | | | | | - Jian-Dong Duan
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, NY 10595, USA
| | | | - Benjamin Smith
- Monell Chemical Senses Center, Philadelphia, PA 19104, USA
| | - Gary M Williams
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, NY 10595, USA
| |
Collapse
|
2
|
Zhang X, Mahajan JS, J Korley LT, Epps TH, Wu C. Reduced genotoxicity of lignin-derivable replacements to bisphenol A studied using in silico, in vitro, and in vivo methods. MUTATION RESEARCH. GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2023; 885:503577. [PMID: 36669816 DOI: 10.1016/j.mrgentox.2022.503577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 11/29/2022] [Accepted: 12/07/2022] [Indexed: 12/14/2022]
Abstract
Bisguaiacols, lignin-derivable bisphenols, are considered promising and possibly safer alternatives to bisphenol A (BPA), but comprehensive toxicity investigations are needed to ensure safety. Most toxicity studies of BPA and its analogues have focused on potential estrogenic activity, and only limited toxicological data are available on other toxicity aspects, such as genotoxicity at low exposure levels. In this study, the genotoxicity of six lignin-derivable bisguaiacols with varying regioisomer contents and degrees of methoxy substitution was investigated using a multi-tiered method, consisting of in silico simulations, in vitro Ames tests, and in vivo comet tests. The toxicity estimation software tool, an application that predicts toxicity of chemicals using quantitative structure-activity relationships, calculated that the majority of the lignin-derivable bisguaiacols were non-mutagenic. These results were supported by Ames tests using five tester strains (TA98, TA100, TA102, TA1535, and TA1537) at concentrations ranging from 0.5 pmol/plate to 5 nmol/plate. The potential genotoxicity of bisguaiacols was further evaluated using in vivo comet testing in fetal chicken livers, and in addition to the standard alkaline comet assay, the formamidopyrimidine DNA glycosylase enzyme-modified comet assay was employed to investigate oxidative DNA damage in the liver samples. The oxidative stress analyses indicated that the majority of lignin-derivable analogues showed no signs of mutagenicity (mutagenic index < 1.5) or genotoxicity, in comparison to BPA and bisphenol F, likely due to the methoxy groups on the lignin-derivable aromatics. These findings reinforce the potential of lignin-derivable bisphenols as safer alternatives to BPA.
Collapse
Affiliation(s)
- Xinwen Zhang
- Department of Animal and Food Sciences, University of Delaware, Newark, DE 19716, United States
| | - Jignesh S Mahajan
- Department of Materials Science and Engineering, University of Delaware, Newark, DE 19716, United States
| | - LaShanda T J Korley
- Department of Materials Science and Engineering, University of Delaware, Newark, DE 19716, United States; Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716, United States
| | - Thomas H Epps
- Department of Materials Science and Engineering, University of Delaware, Newark, DE 19716, United States; Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716, United States
| | - Changqing Wu
- Department of Animal and Food Sciences, University of Delaware, Newark, DE 19716, United States.
| |
Collapse
|
3
|
Kobets T, Smith BPC, Williams GM. Food-Borne Chemical Carcinogens and the Evidence for Human Cancer Risk. Foods 2022; 11:foods11182828. [PMID: 36140952 PMCID: PMC9497933 DOI: 10.3390/foods11182828] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [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.
Collapse
Affiliation(s)
- Tetyana Kobets
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, NY 10595, USA
- Correspondence: ; Tel.: +1-914-594-3105; Fax: +1-914-594-4163
| | - 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
| |
Collapse
|
4
|
Kobets T, Duan JD, Vock E, Deschl U, Williams GM. Evaluation of Pharmaceuticals for DNA Damage in the Chicken Egg Genotoxicity Assay (CEGA). Int J Toxicol 2022; 41:297-311. [PMID: 35658642 DOI: 10.1177/10915818221093583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
DNA damage is an established initiating event in the mutagenicity and carcinogenicity of genotoxic chemicals. Accordingly, assessment of this endpoint is critical for chemicals which are being developed for use in humans. To assess the ability of the Chicken Egg Genotoxicity Assay (CEGA) to detect genotoxic pharmaceuticals, a set of 23 compounds with different pharmacological and reported genotoxic effects was tested for the potential to produce nuclear DNA adducts and strand breaks in the embryo-fetal livers using the 32P-nucleotide postlabeling (NPL) and comet assays, respectively. Due to high toxicity, two aneugens, colchicine and vinblastine, and an autophagy inhibitor, hydroxychloroquine, could not be evaluated. Out of the 20 remaining pharmaceuticals, 10 including estrogen modulators, diethylstilbestrol and tamoxifen, antineoplastics cyclophosphamide, etoposide, and mitomycin C, antifungal griseofulvin, local anesthetics lidocaine and prilocaine, and antihistamines diphenhydramine and doxylamine, yielded clear positive outcomes in at least one of the assays. The antihypertensive vasodilator hydralazine and antineoplastics streptozotocin and teniposide, produced only DNA strand breaks, which were not dose-dependent, and thus, the results with these 3 pharmaceuticals were considered equivocal. No DNA damage was detected for 7 compounds, including the purine antagonist 6-thioguanine, antipyretic analgesics acetaminophen and phenacetin, antibiotic ciprofloxacin, antilipidemic clofibrate, anti-inflammatory ibuprofen, and sedative phenobarbital. However, low solubility of these compounds limited dosages tested in CEGA. Overall, results in CEGA were largely in concordance with the outcomes in other systems in vitro and in vivo, indicating that CEGA provides reliable detection of DNA damaging activity of genotoxic compounds. Further evaluations with a broader set of compounds would support this conclusion.
Collapse
Affiliation(s)
- Tetyana Kobets
- Department of Pathology, Immunology and Microbiology, 8137New York Medical College, Valhalla, NY, USA
| | - Jian-Dong Duan
- Department of Pathology, Immunology and Microbiology, 8137New York Medical College, Valhalla, NY, USA
| | - Esther Vock
- Boehringer Ingelheim Pharma GmbH&Co. KG, Biberach an der Riss, Germany
| | - Ulrich Deschl
- Boehringer Ingelheim Pharma GmbH&Co. KG, Biberach an der Riss, Germany
| | - Gary M Williams
- Department of Pathology, Immunology and Microbiology, 8137New York Medical College, Valhalla, NY, USA
| |
Collapse
|
5
|
Ghimire S, Zhang X, Zhang J, Wu C. Use of Chicken Embryo Model in Toxicity Studies of Endocrine-Disrupting Chemicals and Nanoparticles. Chem Res Toxicol 2022; 35:550-568. [PMID: 35286071 DOI: 10.1021/acs.chemrestox.1c00399] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Lab animals such as mice and rats are widely used in toxicity research of food additive and pharmaceutics, despite the well-recognized research limitation such as the inability to simulate human neurological diseases, faster absorption of chemicals, big variations among species, and high cost when using a large number of animals. The Society of Toxicology's guidance now focuses on minimizing discomfort and distress of lab animals, finding alternative ways to reduce animal number, replacing animals with in vitro models, and complying to the animal welfare policies. The chicken embryonic model can be a better alternative to mice and rats because of its abundant availability and cost-effectiveness. It can be studied in both laboratory and natural environment, with easy manipulation in ovo or in vivo. The objective of this review paper is to evaluate the use of chicken embryonic model in toxicity evaluation for endocrine-disrupting chemicals (EDCs) and nanoparticles (NPs) by different end points to determine more comprehensive toxic responses. The end points include chicken embryonic mortality and hatchability, developmental malformation analysis, hormonal imbalance, physiological changes in endocrine organs, and antiangiogenesis. Major research methodologies using chicken embryos are also summarized to demonstrate their versatile practice and valuable application in modern toxicity evaluation of EDCs and NPs.
Collapse
Affiliation(s)
- Shweta Ghimire
- University of Delaware, Department of Animal and Food sciences, Newark, Delaware 19716, United States
| | - Xinwen Zhang
- University of Delaware, Department of Animal and Food sciences, Newark, Delaware 19716, United States
| | - Jinglin Zhang
- University of Delaware, Department of Animal and Food sciences, Newark, Delaware 19716, United States
| | - Changqing Wu
- University of Delaware, Department of Animal and Food sciences, Newark, Delaware 19716, United States
| |
Collapse
|
6
|
Alhamdow A, Essig YJ, Krais AM, Gustavsson P, Tinnerberg H, Lindh CH, Hagberg J, Graff P, Albin M, Broberg K. Fluorene exposure among PAH-exposed workers is associated with epigenetic markers related to lung cancer. Occup Environ Med 2020; 77:488-495. [PMID: 32385190 PMCID: PMC7306866 DOI: 10.1136/oemed-2020-106413] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 04/02/2020] [Accepted: 04/05/2020] [Indexed: 01/03/2023]
Abstract
Objectives Exposure to high-molecular-weight polycyclic aromatic hydrocarbons (PAHs) may cause cancer in chimney sweeps and creosote-exposed workers, however, knowledge about exposure to low-molecular-weight PAHs in relation to cancer risk is limited. In this study, we aimed to investigate occupational exposure to the low-molecular-weight PAHs phenanthrene and fluorene in relation to different cancer biomarkers. Methods We recruited 151 chimney sweeps, 19 creosote-exposed workers and 152 unexposed workers (controls), all men. We measured monohydroxylated metabolites of phenanthrene and fluorene in urine using liquid chromatography coupled to tandem mass spectrometry. We measured, in peripheral blood, the cancer biomarkers telomere length and mitochondrial DNA copy number using quantitative PCR; and DNA methylation of F2RL3 and AHRR using pyrosequencing. Results Median PAH metabolite concentrations were higher among chimney sweeps (up to 3 times) and creosote-exposed workers (up to 353 times), compared with controls (p<0.001; adjusted for age and smoking). ∑OH-fluorene (sum of 2-hydroxyfluorene and 3-hydroxyfluorene) showed inverse associations with percentage DNA methylation of F2RL3 and AHRR in chimney sweeps (B (95% CI)=–2.7 (–3.9 to –1.5) for F2RL3_cg03636183, and –7.1 (–9.6 to –4.7) for AHRR_cg05575921: adjusted for age and smoking), but not in creosote-exposed workers. In addition, ∑OH-fluorene showed a 42% mediation effect on the inverse association between being a chimney sweep and DNA methylation of AHRR CpG2. Conclusions Chimney sweeps and creosote-exposed workers were occupationally exposed to low-molecular-weight PAHs. Increasing fluorene exposure, among chimney sweeps, was associated with lower DNA methylation of F2RL3 and AHRR, markers for increased lung cancer risk. These findings warrant further investigation of fluorene exposure and toxicity.
Collapse
Affiliation(s)
- Ayman Alhamdow
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Yona J Essig
- Department of Laboratory Medicine, Division of Occupational and Environmental Medicine, Lund University, Lund, Sweden
| | - Annette M Krais
- Department of Laboratory Medicine, Division of Occupational and Environmental Medicine, Lund University, Lund, Sweden
| | - Per Gustavsson
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.,Region Stockholm, Centre for Occupational and Environmental Medicine, Stockholm, Sweden
| | - Håkan Tinnerberg
- School of Public Health and Community Medicine, Section of Occupational and Environmental Medicine, University of Gothenburg Sahlgrenska Academy, Göteborg, Sweden
| | - Christian H Lindh
- Department of Laboratory Medicine, Division of Occupational and Environmental Medicine, Lund University, Lund, Sweden
| | - Jessika Hagberg
- MTM Research Centre, Örebro universitet Akademin för Naturvetenskap och Teknik, Orebro, Sweden.,Department of Occupational and Environmental Medicine, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Pål Graff
- Department of Chemical and Biological Work Environment, STAMI, Oslo, Norway
| | - Maria Albin
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Laboratory Medicine, Division of Occupational and Environmental Medicine, Lund University, Lund, Sweden.,Region Stockholm, Centre for Occupational and Environmental Medicine, Stockholm, Sweden
| | - Karin Broberg
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden .,Department of Laboratory Medicine, Division of Occupational and Environmental Medicine, Lund University, Lund, Sweden
| |
Collapse
|
7
|
Declining BRCA-Mediated DNA Repair in Sperm Aging and its Prevention by Sphingosine-1-Phosphate. Reprod Sci 2020; 27:940-953. [PMID: 31916095 DOI: 10.1007/s43032-019-00098-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 07/17/2019] [Indexed: 12/28/2022]
Abstract
Recent data suggest that paternal age can have major impact on reproductive outcomes, and with increased age, there is increased likelihood of chromosomal abnormalities in the sperm. Here, we studied DNA damage and repair as a function of male aging and assessed whether sphingosine-1-phosphate (S1P), a ceramide-induced death inhibitor, can prevent sperm aging by enhancing DNA double-strand breaks (DSB) repair. We observed a significant increase in DNA damage with age and this increase was associated with a decline in the expression of key DNA DSB repair genes in mouse sperm. The haploinsufficiency of BRCA1 male mice sperm showed significantly increased DNA damage and apoptosis, along with decreased chromatin integrity when compared to similar age wild type (WT) mice. Furthermore, haploinsufficiency of BRCA1 male mice had lower sperm count and smaller litter size when crossed with WT females. The resulting embryos had a higher probability of growth arrest and reduced implantation. S1P treatment decreased genotoxic-stress-induced DNA damage in sperm and enhanced the expressions of key DNA repair genes such as BRCA1. Co-treatment with an ATM inhibitor reversed the effects of S1P, implying that the impact of S1P on DNA repair is via the ATM-mediated pathway. Our findings indicate a key role for DNA damage repair mechanism in the maintenance of sperm integrity and suggest that S1P can improve DNA repair in sperm. Further translational studies are warranted to determine the clinical significance of these findings and whether S1P can delay male reproductive aging. There is mounting evidence that sperm quality declines with age, similar to that of the oocyte. However, the reasons behind this decline are poorly understood and there is no medical intervention to improve sperm quality. Our study suggests a strong role for DNA damage repair in maintenance of sperm quality, and for the first time, a potential pharmaceutical approach to prevent sperm aging.
Collapse
|
8
|
Kobets T, Iatropoulos MJ, Duan JD, Brunnemann KD, Iacobas DA, Iacobas S, Vock E, Deschl U, Williams GM. Expression of Genes Encoding for Xenobiotic Metabolism After Exposure to Dialkylnitrosamines in the Chicken Egg Genotoxicity Alternative Model. Toxicol Sci 2019; 166:82-96. [PMID: 30102407 DOI: 10.1093/toxsci/kfy197] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The Chicken Egg Genotoxicity Assay (CEGA) demonstrated responsiveness to various DNA-reactive chemicals requiring metabolic activation, which implies broad bioactivation capability. To assess potential metabolic competence, expression profiles of metabolic genes in the embryo-chicken fetal liver were determined using microarray technology. Fertilized chicken eggs were injected under the CEGA protocol with vehicle (deionized water [DW]), the activation-dependent carcinogens, diethylnitrosamine (DEN), and N-nitrosodiethanolamine (NDELA) at doses producing no effect on survival. Previously in CEGA, DEN produced DNA damage, whereas NDELA did not. Expressions of 463 genes known to encode for phase I and II of endo- and xenobiotic metabolism were detected on the array. DW did not affect the expression of the selected genes, deregulating less than 1% of them. In contrast, DEN at 2 mg/egg and NDELA at 4 mg/egg produced significant transcriptomic alterations, up-regulating up to 41% and down-regulating over 31% of studied genes. Both nitrosamines modulated the majority of the genes in a similar manner, sharing 64 up-regulated and 93 down-regulated genes with respect to control group, indicating similarity in the regulation of their metabolism by avian liver. Differences in gene expression between DEN and NDELA were documented for several phase I CYP 450 genes that are responsible for nitrosamine biotransformation, as well as for phase II genes that regulate detoxication reactions. These findings could underlie the difference in genotoxicity of DEN and NDELA in CEGA. In conclusion, the analysis of gene expression profiles in embryo-chicken fetal liver dosed with dialkylnitrosamines demonstrated that avian species possess a complex array of inducible genes coding for biotransformation.
Collapse
Affiliation(s)
- Tetyana Kobets
- Department of Pthology, New York Medical College, Valhalla, New York 10595
| | | | - Jiandong D Duan
- Department of Pthology, New York Medical College, Valhalla, New York 10595
| | - Klaus D Brunnemann
- Department of Pthology, New York Medical College, Valhalla, New York 10595
| | - Dumitru A Iacobas
- Center for Computational Systems Biology, Prairie View A&M University, Prairie View, Texas 77446
| | - Sanda Iacobas
- Department of Pthology, New York Medical College, Valhalla, New York 10595
| | - Esther Vock
- Boehringer Ingelheim Pharma GmbH&Co. KG, Biberach an der Riss, Germany 88397
| | - Ulrich Deschl
- Boehringer Ingelheim Pharma GmbH&Co. KG, Biberach an der Riss, Germany 88397
| | - Gary M Williams
- Department of Pthology, New York Medical College, Valhalla, New York 10595
| |
Collapse
|
9
|
Kobets T, Duan JD, Brunnemann KD, Vock E, Deschl U, Williams GM. DNA-damaging activities of twenty-four structurally diverse unsubstituted and substituted cyclic compounds in embryo-fetal chicken livers. Mutat Res 2019; 844:10-24. [PMID: 31326031 DOI: 10.1016/j.mrgentox.2019.06.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 05/28/2019] [Accepted: 06/13/2019] [Indexed: 01/28/2023]
Abstract
DNA-damaging activities of twenty-four structurally diverse unsubstituted and substituted cyclic compounds were assessed in embryo-fetal chicken livers. Formation of DNA adducts and strand breaks were measured using the nucleotide 32P-postlabelling (NPL) and comet assays, respectively. Unsubstituted monocyclic benzene, polycyclic fused ring compound naphthalene, covalently connected polycyclic ring compound biphenyl, and heterocyclic ring compound fluorene did not produce DNA damage. Amino-substituted monocyclic compounds, aniline and p-phenylenediamine, as well as polycyclic 1-naphthylamine were also negative. In contrast, carcinogenic monocyclic methyl-substituted anilines: o-toluidine, 2,6-xylidine, 3,4-dimethylaniline, 4-chloro-o-toluidine; 2 methoxy-substituted methylaniline: p-cresidine; 2,4 and 2,6 diamino- or dinitro- substituted toluenes all produced DNA damage. Genotoxic polycyclic amino-substituted 2-naphthylamine, 4-aminobiphenyl, benzidine, methyl-substituted 3,2'-dimethyl-4-aminobiphenyl and 4-dimethylaminoazobenzene as well as amino- and nitro- fluorenes substituted at the 1 or 2 positions also were positive in at least one of the assays. Overall, the DNA damaging activity of cyclic compounds in embryo-fetal chicken livers reflected the type and position of the substitution on the aromatic ring. Additionally, substituted polycyclic compounds exhibited higher DNA-damaging potency compared to monocyclic chemicals. These results are congruent with in vivo findings in other species, establishing chicken eggs as a reliable system for structure-activity assessment of members of groups of related chemicals.
Collapse
Affiliation(s)
- Tetyana Kobets
- Department of Pathology, New York Medical College, Valhalla, NY, 10595, USA.
| | - Jian-Dong Duan
- Department of Pathology, New York Medical College, Valhalla, NY, 10595, USA.
| | - Klaus D Brunnemann
- Department of Pathology, New York Medical College, Valhalla, NY, 10595, USA.
| | - Esther Vock
- Boehringer Ingelheim Pharma GmbH & Co, Biberach an der Riss, Germany.
| | - Ulrich Deschl
- Boehringer Ingelheim Pharma GmbH & Co, Biberach an der Riss, Germany.
| | - Gary M Williams
- Department of Pathology, New York Medical College, Valhalla, NY, 10595, USA.
| |
Collapse
|
10
|
Kobets T, Cartus AT, Fuhlbrueck JA, Brengel A, Stegmüller S, Duan JD, Brunnemann KD, Williams GM. Assessment and characterization of DNA adducts produced by alkenylbenzenes in fetal turkey and chicken livers. Food Chem Toxicol 2019; 129:424-433. [PMID: 31077736 DOI: 10.1016/j.fct.2019.05.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 05/04/2019] [Accepted: 05/07/2019] [Indexed: 01/22/2023]
Abstract
Formation of DNA adducts by five alkenylbenzenes, safrole, methyl eugenol, eugenol, and asarone with either α- or β-conformation, was analyzed in fetal avian livers in two in ovo models. DNA reactivity of the carcinogens safrole and methyl eugenol was previously demonstrated in the turkey egg model, whereas non-genotoxic eugenol was negative. In the current study, alkenylbenzenes were also tested in the chicken egg model. Injections with alkenylbenzenes were administered to fertilized turkey or chicken eggs for three consecutive days. Three hours after the last injection, liver samples were evaluated for DNA adduct formation using the 32P-nucleotide postlabeling assay. DNA samples from turkey livers were also analyzed for adducts using mass spectrometry. In both species, genotoxic alkenylbenzenes safrole, methyl eugenol, α- and β-asarone produced DNA adducts, the presence and nature of which, with exception of safrole, were confirmed by mass spectrometry, validating the sensitivity of the 32P-postlabeling assay. Overall, the results of testing were congruent between fetal turkey and chicken livers, confirming that these organisms can be used interchangeably. Moreover, data obtained in both models is comparable to genotoxicity findings in other species, supporting the usefulness of avian models for the assessment of genotoxicity as a potential alternative to animal models.
Collapse
Affiliation(s)
- Tetyana Kobets
- New York Medical College, Department of Pathology, 40 Sunshine Cottage Road, Valhalla, NY, 10595, USA.
| | - Alexander T Cartus
- University of Kaiserslautern, Food Chemistry and Toxicology, Erwin-Schrödinger-Strasse 52, 67663, Kaiserslautern, Germany
| | - Julia A Fuhlbrueck
- University of Kaiserslautern, Food Chemistry and Toxicology, Erwin-Schrödinger-Strasse 52, 67663, Kaiserslautern, Germany
| | - Alexander Brengel
- University of Kaiserslautern, Food Chemistry and Toxicology, Erwin-Schrödinger-Strasse 52, 67663, Kaiserslautern, Germany
| | - Simone Stegmüller
- University of Kaiserslautern, Food Chemistry and Toxicology, Erwin-Schrödinger-Strasse 52, 67663, Kaiserslautern, Germany
| | - Jian-Dong Duan
- New York Medical College, Department of Pathology, 40 Sunshine Cottage Road, Valhalla, NY, 10595, USA
| | - Klaus D Brunnemann
- New York Medical College, Department of Pathology, 40 Sunshine Cottage Road, Valhalla, NY, 10595, USA
| | - Gary M Williams
- New York Medical College, Department of Pathology, 40 Sunshine Cottage Road, Valhalla, NY, 10595, USA
| |
Collapse
|
11
|
Kobets T, Iatropoulos MJ, Williams GM. Mechanisms of DNA-reactive and epigenetic chemical carcinogens: applications to carcinogenicity testing and risk assessment. Toxicol Res (Camb) 2019; 8:123-145. [PMID: 30997017 PMCID: PMC6417487 DOI: 10.1039/c8tx00250a] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Accepted: 12/18/2018] [Indexed: 01/03/2023] Open
Abstract
Chemicals with carcinogenic activity in either animals or humans produce increases in neoplasia through diverse mechanisms. One mechanism is reaction with nuclear DNA. Other mechanisms consist of epigenetic effects involving either modifications of regulatory macromolecules or perturbation of cellular regulatory processes. The basis for distinguishing between carcinogens that have either DNA reactivity or an epigenetic activity as their primary mechanism of action is detailed in this review. In addition, important applications of information on these mechanisms of action to carcinogenicity testing and human risk assessment are discussed.
Collapse
Affiliation(s)
- Tetyana Kobets
- Department of Pathology , New York Medical College , Valhalla , NY 10595 , USA . ; ; Tel: +1 914-594-3105
| | - Michael J Iatropoulos
- Department of Pathology , New York Medical College , Valhalla , NY 10595 , USA . ; ; Tel: +1 914-594-3105
| | - Gary M Williams
- Department of Pathology , New York Medical College , Valhalla , NY 10595 , USA . ; ; Tel: +1 914-594-3105
| |
Collapse
|
12
|
Kobets T, Duan JD, Brunnemann KD, Iatropoulos MJ, Etter S, Hickey C, Smith B, Williams GM. In ovo testing of flavor and fragrance materials in Turkey Egg Genotoxicity Assay (TEGA), comparison of results to in vitro and in vivo data. Food Chem Toxicol 2018; 115:228-243. [DOI: 10.1016/j.fct.2018.03.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 03/09/2018] [Accepted: 03/12/2018] [Indexed: 10/17/2022]
|
13
|
Lucendo-Villarin B, Filis P, Swortwood MJ, Huestis MA, Meseguer-Ripolles J, Cameron K, Iredale JP, O'Shaughnessy PJ, Fowler PA, Hay DC. Modelling foetal exposure to maternal smoking using hepatoblasts from pluripotent stem cells. Arch Toxicol 2017; 91:3633-3643. [PMID: 28510779 PMCID: PMC5696490 DOI: 10.1007/s00204-017-1983-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Accepted: 05/08/2017] [Indexed: 12/17/2022]
Abstract
The liver is a dynamic organ which is both multifunctional and highly regenerative. A major role of the liver is to process both endo and xenobiotics. Cigarettes are an example of a legal and widely used drug which can cause major health problems for adults and constitute a particular risk to the foetus, if the mother smokes during pregnancy. Cigarette smoke contains a complex mixture of thousands of different xenobiotics, including nicotine and polycyclic aromatic hydrocarbons. These affect foetal development in a sex-specific manner, inducing sex-dependant molecular responses in different organs. To date, the effect of maternal smoking on the foetal liver has been studied in vitro using cell lines, primary tissue and animal models. While these models have proven to be useful, poor cell phenotype, tissue scarcity, batch-to-batch variation and species differences have led to difficulties in data extrapolation toward human development. Therefore, in this study we have employed hepatoblasts, derived from pluripotent stem cells, to model the effects of xenobiotics from cigarette smoke on human hepatocyte development. Highly pure hepatocyte populations (>90%) were produced in vitro and exposed to factors present in cigarette smoke. Analysis of ATP levels revealed that, independent of the sex, the majority of smoking derivatives tested individually did not deplete ATP levels below 50%. However, following exposure to a cocktail of smoking derivatives, ATP production fell below 50% in a sex-dependent manner. This was paralleled by a loss metabolic activity and secretory ability in both female and male hepatocytes. Interestingly, cell depletion was less pronounced in female hepatocytes, whereas caspase activation was ~twofold greater, indicating sex differences in cell death upon exposure to the smoking derivatives tested.
Collapse
Affiliation(s)
- Baltasar Lucendo-Villarin
- Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, 5 Little France Drive, Edinburgh, EH16 4UU, Scotland, UK
| | - Panagiotis Filis
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Madeleine J Swortwood
- Department of Forensic Science, College of Criminal Justice, Sam Houston State University, Huntsville, TX, USA
| | - Marilyn A Huestis
- University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Jose Meseguer-Ripolles
- Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, 5 Little France Drive, Edinburgh, EH16 4UU, Scotland, UK
| | - Kate Cameron
- Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, 5 Little France Drive, Edinburgh, EH16 4UU, Scotland, UK
| | - John P Iredale
- University of Bristol, Senate House, Tyndall Avenue, Bristol, BS8 1TH, UK
| | - Peter J O'Shaughnessy
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, G61 1QH, UK
| | - Paul A Fowler
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - David C Hay
- Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, 5 Little France Drive, Edinburgh, EH16 4UU, Scotland, UK.
| |
Collapse
|
14
|
Chicken egg fetal liver DNA and histopathologic effects of structurally diverse carcinogens and non-carcinogens. ACTA ACUST UNITED AC 2017; 69:533-546. [DOI: 10.1016/j.etp.2017.04.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 03/01/2017] [Accepted: 04/26/2017] [Indexed: 11/23/2022]
|
15
|
Williams GM, Kobets T, Duan JD, Iatropoulos MJ. Assessment of DNA Binding and Oxidative DNA Damage by Acrylonitrile in Two Rat Target Tissues of Carcinogenicity: Implications for the Mechanism of Action. Chem Res Toxicol 2017; 30:1470-1480. [DOI: 10.1021/acs.chemrestox.7b00105] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Gary M. Williams
- Chemical Safety Program,
Department of Pathology, New York Medical College, Valhalla, New York 10595, United States
| | - Tetyana Kobets
- Chemical Safety Program,
Department of Pathology, New York Medical College, Valhalla, New York 10595, United States
| | - Jian-Dong Duan
- Chemical Safety Program,
Department of Pathology, New York Medical College, Valhalla, New York 10595, United States
| | - Michael J. Iatropoulos
- Chemical Safety Program,
Department of Pathology, New York Medical College, Valhalla, New York 10595, United States
| |
Collapse
|
16
|
Nisha AR, Hazilawati H, Mohd Azmi ML, Noordin MM. DNA damage and adduct formation in immune organs of developing chicks by polycyclic aromatic hydrocarbons. Toxicol Mech Methods 2017; 27:215-222. [DOI: 10.1080/15376516.2016.1273432] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- A. R. Nisha
- Department of Pathology and Microbiology, Faculty of Veterinary Medicine, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary and Animal sciences, Wayanad, Kerala, India
| | - H. Hazilawati
- Department of Pathology and Microbiology, Faculty of Veterinary Medicine, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - M. L. Mohd Azmi
- Department of Pathology and Microbiology, Faculty of Veterinary Medicine, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - M. M. Noordin
- Department of Pathology and Microbiology, Faculty of Veterinary Medicine, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| |
Collapse
|
17
|
Williams GM, Kobets T, Iatropoulos MJ, Duan JD, Brunnemann KD. GRAS determination scientific procedures and possible alternatives. Regul Toxicol Pharmacol 2016; 79 Suppl 2:S105-11. [PMID: 27328372 DOI: 10.1016/j.yrtph.2016.06.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 06/15/2016] [Indexed: 11/27/2022]
Abstract
The use of a food substance is Generally Recognized as Safe (GRAS) through scientific procedures or experience based on common use in food. The pivotal data used for GRAS determination must be of common knowledge and should include evidence for safety under the conditions of intended use of the substance. Such evidence includes data on the identity and specifications of the substance, its properties of absorption, distribution, metabolism and excretion, and depending on the level of concern, data on genotoxicity, acute and subchronic toxicity, reproductive and developmental toxicity and carcinogenicity. Several alternative procedures can be used as the replacement for standard scientific procedures in order to improve the GRAS process.
Collapse
Affiliation(s)
- Gary M Williams
- Department of Pathology, New York Medical College, 40Sunshine Cottage Road, BSB # 413, Valhalla, NY, 10595, USA.
| | - Tetyana Kobets
- Department of Pathology, New York Medical College, 40Sunshine Cottage Road, BSB # 413, Valhalla, NY, 10595, USA
| | - Michael J Iatropoulos
- Department of Pathology, New York Medical College, 40Sunshine Cottage Road, BSB # 413, Valhalla, NY, 10595, USA
| | - Jian-Dong Duan
- Department of Pathology, New York Medical College, 40Sunshine Cottage Road, BSB # 413, Valhalla, NY, 10595, USA
| | - Klaus D Brunnemann
- Department of Pathology, New York Medical College, 40Sunshine Cottage Road, BSB # 413, Valhalla, NY, 10595, USA
| |
Collapse
|
18
|
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
|
19
|
Iatropoulos MJ, Duan JD, Schmuck G, Williams GM. The urinary bladder carcinogen propoxur does not produce genotoxic effects in the urinary bladder of Wistar male rats. ACTA ACUST UNITED AC 2015; 67:453-8. [PMID: 26164753 DOI: 10.1016/j.etp.2015.06.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 06/03/2015] [Accepted: 06/08/2015] [Indexed: 11/19/2022]
Abstract
Propoxur (PPX) is a carbamate insecticide which induced urinary bladder cancer in Wistar rats when fed at 5000ppm in Altromin 1321 diet (1321). In the present investigation, PPX was studied for induction of several key events related to modes of action (MOA) of carcinogenicity in urinary bladders (UBs). Wistar rats were administered the compound for 28 days at 8000ppm in Provini Liba SA 3883 diet, which is similar to the 1321 diet. o-Anisidine HCl (AH) was used as a genotoxic UB carcinogenic comparator, and trisodium nitrilotriacetate (NTA) as an epigenetic UB carcinogen comparator. Along with the non-dosed control and three test substance groups (PPX, AH, NTA), four more groups were additionally fed 2% ammonium chloride (AC) in the diet to acidify the urine, since 1321 was reported to increase urinary pH. AC did acidify the urine, as expected, although the 3883 diet itself did not increase pH values above 8. In the alkaline comet assay, AH produced DNA single strand breaks (SSBs) in the UB urothelium (UBU) irrespective of AC administration, whereas PPX and NTA did not. In the nucleotide (32)P-postlabeling assay (NPL), AH produced DNA adducts irrespective of AC administration, whereas PPX and NTA did not. Routine (H&E) histopathology evaluation of the UBU did not reveal any hyperplasia or evidence of luminal microprecipitates or calculi in any of the groups. Assessment of UBU proliferation as measured by immunohistochemistry of proliferating cell nuclear antigen, revealed that NTA and NTA plus AC increased the replicating fraction (RF). Also AH plus AC, but not AH alone, increased the RF of UBU, whereas PPX groups were not significantly different from controls. Thus, the results reveal no evidence for DNA SSBs, binding, or alteration of DNA synthesis in the UBU by PPX, while demonstrating UBU DNA damage by AH and showing that NTA does not damage DNA, but causes increased UBU proliferation. The findings are in accord with a genotoxic MOA for AH, and an epigenetic MOA for NTA. The MOA of PPX does not involve genotoxicity and may be specific to the 1321 diet.
Collapse
Affiliation(s)
| | - J-D Duan
- New York Medical College, Valhalla, NY 10595, USA
| | - G Schmuck
- Bayer Schering Pharma AG, D-42096 Wuppertal, Germany
| | - G M Williams
- New York Medical College, Valhalla, NY 10595, USA.
| |
Collapse
|