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Eaton DL, Simon TW, Kaminski NE, Perdew GH, Nebert DW. Species differences in specific ligand-binding affinity and activation of AHR: The biological basis for calculation of relative effective potencies and toxic equivalence factors. Regul Toxicol Pharmacol 2024; 149:105598. [PMID: 38548044 DOI: 10.1016/j.yrtph.2024.105598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/25/2024] [Accepted: 03/05/2024] [Indexed: 05/01/2024]
Abstract
In 2022 the World Health Organization (WHO) published updated 'Toxic Equivalence Factors' (TEFs) for a wide variety of chlorinated dioxins, dibenzofurans and PCBs [collectively referred to as 'dioxin-like chemicals'; DLCs) that interact with the aryl hydrocarbon receptor (AHR)]. Their update used sophisticated statistical analysis of hundreds of published studies that reported estimation of 'Relative Effective Potency' (REP) values for individual DLC congeners. The weighting scheme used in their assessment of each study favored in vivo over in vitro studies and was based largely on rodent studies. In this Commentary, we highlight the large body of published studies that demonstrate large species differences in AHR-ligand activation and provide supporting evidence for our position that the WHO 2022 TEF values intended for use in human risk assessment of DLC mixtures will provide highly misleading overestimates of 'Toxic Equivalent Quotients' (TEQs), because of well-recognized striking differences in AHR ligand affinities between rodent (rat, mouse) and human. The data reviewed in our Commentary support the position that human tissue-derived estimates of REP/TEF values for individual DLC congeners, although uncertain, will provide much better, more realistic estimates of potential activation of the human AHR, when exposure to complex DLC mixtures occurs.
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Affiliation(s)
- David L Eaton
- Department of Environmental Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA, USA.
| | | | - Norbert E Kaminski
- Department of Pharmacology and Toxicology, Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, USA
| | - Gary H Perdew
- The Pennsylvania State University, State College, PA, USA
| | - Daniel W Nebert
- Department of Environmental and Public Health Sciences, Center for Environmental Genetics, University of Cincinnati College of Medicine, USA; Department of Pediatrics & Molecular Developmental Biology, Division of Human Genetics, Cincinnati Children's Research Foundation, Cincinnati, OH, USA
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2
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Sanz-Serrano J, Callewaert E, De Boever S, Drees A, Verhoeven A, Vinken M. Chemical-induced liver cancer: an adverse outcome pathway perspective. Expert Opin Drug Saf 2024; 23:425-438. [PMID: 38430529 DOI: 10.1080/14740338.2024.2326479] [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: 11/15/2023] [Accepted: 02/29/2024] [Indexed: 03/04/2024]
Abstract
INTRODUCTION The evaluation of the potential carcinogenicity is a key consideration in the risk assessment of chemicals. Predictive toxicology is currently switching toward non-animal approaches that rely on the mechanistic understanding of toxicity. AREAS COVERED Adverse outcome pathways (AOPs) present toxicological processes, including chemical-induced carcinogenicity, in a visual and comprehensive manner, which serve as the conceptual backbone for the development of non-animal approaches eligible for hazard identification. The current review provides an overview of the available AOPs leading to liver cancer and discusses their use in advanced testing of liver carcinogenic chemicals. Moreover, the challenges related to their use in risk assessment are outlined, including the exploitation of available data, the need for semantic ontologies, and the development of quantitative AOPs. EXPERT OPINION To exploit the potential of liver cancer AOPs in the field of risk assessment, 3 immediate prerequisites need to be fulfilled. These include developing human relevant AOPs for chemical-induced liver cancer, increasing the number of AOPs integrating quantitative toxicodynamic and toxicokinetic data, and developing a liver cancer AOP network. As AOPs and other areas in the field continue to evolve, liver cancer AOPs will progress into a reliable and robust tool serving future risk assessment and management.
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Affiliation(s)
- Julen Sanz-Serrano
- In Vitro Toxicology and Dermato-Cosmetology Research Group, Vrije Universiteit Brussel, Brussels, Belgium
| | - Ellen Callewaert
- In Vitro Toxicology and Dermato-Cosmetology Research Group, Vrije Universiteit Brussel, Brussels, Belgium
| | - Sybren De Boever
- In Vitro Toxicology and Dermato-Cosmetology Research Group, Vrije Universiteit Brussel, Brussels, Belgium
| | - Annika Drees
- In Vitro Toxicology and Dermato-Cosmetology Research Group, Vrije Universiteit Brussel, Brussels, Belgium
| | - Anouk Verhoeven
- In Vitro Toxicology and Dermato-Cosmetology Research Group, Vrije Universiteit Brussel, Brussels, Belgium
| | - Mathieu Vinken
- In Vitro Toxicology and Dermato-Cosmetology Research Group, Vrije Universiteit Brussel, Brussels, Belgium
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3
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DeVito M, Bokkers B, van Duursen MBM, van Ede K, Feeley M, Antunes Fernandes Gáspár E, Haws L, Kennedy S, Peterson RE, Hoogenboom R, Nohara K, Petersen K, Rider C, Rose M, Safe S, Schrenk D, Wheeler MW, Wikoff DS, Zhao B, van den Berg M. The 2022 world health organization reevaluation of human and mammalian toxic equivalency factors for polychlorinated dioxins, dibenzofurans and biphenyls. Regul Toxicol Pharmacol 2024; 146:105525. [PMID: 37972849 PMCID: PMC10870838 DOI: 10.1016/j.yrtph.2023.105525] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 10/21/2023] [Accepted: 11/01/2023] [Indexed: 11/19/2023]
Abstract
In October 2022, the World Health Organization (WHO) convened an expert panel in Lisbon, Portugal in which the 2005 WHO TEFs for chlorinated dioxin-like compounds were reevaluated. In contrast to earlier panels that employed expert judgement and consensus-based assignment of TEF values, the present effort employed an update to the 2006 REP database, a consensus-based weighting scheme, a Bayesian dose response modeling and meta-analysis to derive "Best-Estimate" TEFs. The updated database contains almost double the number of datasets from the earlier version and includes metadata that informs the weighting scheme. The Bayesian analysis of this dataset results in an unbiased quantitative assessment of the congener-specific potencies with uncertainty estimates. The "Best-Estimate" TEF derived from the model was used to assign 2022 WHO-TEFs for almost all congeners and these values were not rounded to half-logs as was done previously. The exception was for the mono-ortho PCBs, for which the panel agreed to retain their 2005 WHO-TEFs due to limited and heterogenous data available for these compounds. Applying these new TEFs to a limited set of dioxin-like chemical concentrations measured in human milk and seafood indicates that the total toxic equivalents will tend to be lower than when using the 2005 TEFs.
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Affiliation(s)
- Michael DeVito
- Center for Computational Toxicology and Exposure, United States Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Bas Bokkers
- Centre for Safety of Substances and Products, National Institute for Public Health, And the Environment (RIVM), Bilthoven, the Netherlands
| | - Majorie B M van Duursen
- Amsterdam Institute for Life and Environment, Environmental Health & Toxicology, Vrije Universiteit, Amsterdam, the Netherlands
| | | | | | | | | | - Sean Kennedy
- Department of Biology, University of Ottawa, Canada
| | | | - Ron Hoogenboom
- Wageningen Food Safety Research (WFSR), Wageningen, the Netherlands
| | - Keiko Nohara
- Health and Environmental Risk Division, National Institute for Environmental Studies, Tsukuba, 305-8506, Japan
| | - Kim Petersen
- Department of Nutrition and Food Safety, Standards and Scientific Advice on Food and Nutrition, World Health Organization, Geneva Switzerland.
| | - Cynthia Rider
- National Institute of Environmental Health Science, Division of the Translational Toxicology, Durham, USA
| | - Martin Rose
- FERA Science Ltd, Sand Hutton, York, YO41 1LZ, UK; Manchester Institute of Biotechnology, University of Manchester, Manchester, UK
| | - Stephen Safe
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX, 77843, USA
| | - Dieter Schrenk
- Food Chemistry and Toxicology Department, University of Kaiserslautern, D-67663, Kaiserslautern, Germany
| | - Matthew W Wheeler
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, RTP, NC, USA
| | | | - Bin Zhao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Martin van den Berg
- Institute for Risk Assessment Sciences, Utrecht University, Yalelaan 104, 3584 CM, Utrecht, the Netherlands
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Barouki R. Invited Perspective: Reference Values à la Mode of Action. ENVIRONMENTAL HEALTH PERSPECTIVES 2023; 131:121309. [PMID: 38157271 PMCID: PMC10756337 DOI: 10.1289/ehp13773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 10/13/2023] [Accepted: 12/06/2023] [Indexed: 01/03/2024]
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Hilton GM, Bhuller Y, Doe JE, Wolf DC, Currie RA. A new paradigm for regulatory sciences. Regul Toxicol Pharmacol 2023; 145:105524. [PMID: 37925098 DOI: 10.1016/j.yrtph.2023.105524] [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: 08/11/2023] [Revised: 10/18/2023] [Accepted: 11/01/2023] [Indexed: 11/06/2023]
Abstract
Regulatory science, rooted in legal requirements, provides a mechanism for identifying, assessing, and managing harm to humans and the environment from exposure to hazardous substances. A challenge for regulatory authorities is that many governing laws reflect the scientific paradigm of the mid-20th century. By the nature of legislative processes, most laws are not able to readily adapt to incorporate scientific advances that are inherent in an ever-evolving paradigm. Consequently, the issue of rigid legal frameworks has become prominent in global discussions related to the incorporation of reliable and relevant modern technology to fulfill regulatory needs. To explore this issue, we apply Thomas Kuhn's The Structure of Scientific Revolutions as a conceptual framework to help understand the natural progression of scientific paradigms (from normal science, to anomaly, to crisis, to revolution, and finally to a new normal), identify where we are now in the paradigm cycle, and to explore a path towards a revolution that enables timely implementation of the best available science to fulfil legal requirements.
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Affiliation(s)
- Gina M Hilton
- PETA Science Consortium International e.V., Stuttgart, Germany.
| | | | - John E Doe
- Liverpool John Moores University, Liverpool, United Kingdom
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Chen Q, Zhou Y, Ji C, Klaunig JE, Shao K. Quantitative Integration of Mode of Action Information in Dose-Response Modeling and POD Estimation for Nonmutagenic Carcinogens: A Case Study of TCDD. ENVIRONMENTAL HEALTH PERSPECTIVES 2023; 131:127022. [PMID: 38157272 PMCID: PMC10756338 DOI: 10.1289/ehp12677] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 11/30/2023] [Accepted: 12/06/2023] [Indexed: 01/03/2024]
Abstract
BACKGROUND Traditional dose-response assessment applies different low-dose extrapolation methods for cancer and noncancer effects and assumes that all carcinogens are mutagenic unless strong evidence suggests otherwise. Additionally, primarily focusing on one critical effect, dose-response modeling utilizes limited mode of action (MOA) data to inform low-dose risk. OBJECTIVE We aimed to build a dose-response modeling framework that continuously extends the curve into the low-dose region via a quantitative integration of MOA information and to estimate MOA-based points of departure (PODs) for nonmutagenic carcinogens. METHODS 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) was used as an example to demonstrate the new dose-response modeling framework. There were three major steps included: a) identifying and extracting key quantifiable events (KQEs), b) calculating essential doses that sequentially activate KQEs using the benchmark dose (BMD) methodology, and c) characterizing pathway dose-response relationship for MOA-based POD estimation. RESULTS We identified and extracted six KQEs and corresponding essential events composing the MOA of TCDD-induced liver tumors. With the essential doses estimated from the BMD method using various settings, three link functions were applied to model the pathway dose-response relationship. Given a toxicologically plausible definition of adversity, an MOA-based POD was derived from the pathway dose-response curve. The estimated MOA-based PODs were generally comparable with traditional PODs and can be further used to calculate reference doses (RfDs). CONCLUSIONS The proposed framework quantitatively integrated mechanistic information in the modeling process and provided a promising strategy to harmonize cancer and noncancer dose-response assessment through pathway dose-response modeling. However, the framework can also be limited by data availability and the understanding of the underlying mechanism. https://doi.org/10.1289/EHP12677.
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Affiliation(s)
- Qiran Chen
- Department of Environmental and Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, Florida, USA
| | - Yun Zhou
- Department of Environmental and Occupational Health, School of Public Health—Bloomington, Indiana University, Bloomington, Indiana, USA
| | - Chao Ji
- Department of Environmental and Occupational Health, School of Public Health—Bloomington, Indiana University, Bloomington, Indiana, USA
| | - James E. Klaunig
- Department of Environmental and Occupational Health, School of Public Health—Bloomington, Indiana University, Bloomington, Indiana, USA
| | - Kan Shao
- Department of Environmental and Occupational Health, School of Public Health—Bloomington, Indiana University, Bloomington, Indiana, USA
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Zhou Y, Chen Q, Klaunig JE, Shao K. A mode of action-based probabilistic framework of dose-response assessment for nonmutagenic liver carcinogens: a case study of PCB-126. Toxicol Sci 2023; 196:250-260. [PMID: 37643630 PMCID: PMC10682966 DOI: 10.1093/toxsci/kfad091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023] Open
Abstract
A main function of dose-response assessment is to estimate a "safe" dose in the target population to support chemical risk assessment. Typically, a "safe" dose is developed differently for cancer and noncancer effects based on a 2-step procedure, ie, point of departure (POD) derivation and low-dose extrapolation. However, the current dose-response assessment framework is criticized for its dichotomized strategy without integrating the mode of action (MOA) information. The objective of this study was, based on our previous work, to develop a MOA-based probabilistic dose-response framework that quantitatively synthesizes a biological pathway in a dose-response modeling process to estimate the risk of chemicals that have carcinogenic potential. 3,3',4,4',5-Pentachlorobiphenyl (PCB-126) was exemplified to demonstrate our proposed approach. There were 4 major steps in the new modeling framework, including (1) key quantifiable events (KQEs) identification and extraction, (2) essential dose calculation, (3) MOA-based POD derivation, and (4) MOA-based probabilistic reference dose (RfD) estimation. Compared with reported PODs and traditional RfDs, the MOA-based estimates derived from our approach were comparable and plausible. One key feature of our approach was the use of overall MOA information to build the dose-response relationship on the entire dose continuum including the low-dose region. On the other hand, by adjusting uncertainty and variability in a probabilistic manner, the MOA-based probabilistic RfDs can provide useful insights of health protection for the specific proportion of population. Moreover, the proposed framework had important potential to be generalized to assess different types of chemicals other than nonmutagenic carcinogens, highlighting its utility to improve current chemical risk assessment.
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Affiliation(s)
- Yun Zhou
- Department of Environmental and Occupational Health, School of Public Health—Bloomington, Indiana University, Bloomington, Indiana 47405, USA
| | - Qiran Chen
- Department of Environmental and Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, Florida 32610, USA
| | - James E Klaunig
- Department of Environmental and Occupational Health, School of Public Health—Bloomington, Indiana University, Bloomington, Indiana 47405, USA
| | - Kan Shao
- Department of Environmental and Occupational Health, School of Public Health—Bloomington, Indiana University, Bloomington, Indiana 47405, USA
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Pavuk M, Rosenbaum PF, Lewin MD, Serio TC, Rago P, Cave MC, Birnbaum LS. Polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, pesticides, and diabetes in the Anniston Community Health Survey follow-up (ACHS II): single exposure and mixture analysis approaches. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 877:162920. [PMID: 36934946 DOI: 10.1016/j.scitotenv.2023.162920] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 02/24/2023] [Accepted: 03/13/2023] [Indexed: 05/06/2023]
Abstract
Dioxins and dioxin-like compounds measurements were added to polychlorinated biphenyls (PCBs) and organochlorine pesticides to expand the exposure profile in a follow-up to the Anniston Community Health Survey (ACHS II, 2014) and to study diabetes associations. Participants of ACHS I (2005-2007) still living within the study area were eligible to participate in ACHS II. Diabetes status (type-2) was determined by a doctor's diagnosis, fasting glucose ≥125 mg/dL, or being on any glycemic control medication. Incident diabetes cases were identified in ACHS II among those who did not have diabetes in ACHS I, using the same criteria. Thirty-five ortho-substituted PCBs, 6 pesticides, 7 polychlorinated dibenzo-p-dioxins (PCDD), 10 furans (PCDF), and 3 non-ortho PCBs were measured in 338 ACHS II participants. Dioxin toxic equivalents (TEQs) were calculated for all dioxin-like compounds. Main analyses used logistic regression models to calculate odds ratios (OR) and 95 % confidence intervals (CI). In models adjusted for age, race, sex, BMI, total lipids, family history of diabetes, and taking lipid lowering medication, the highest ORs for diabetes were observed for PCDD TEQ: 3.61 (95 % CI: 1.04, 12.46), dichloro-diphenyl dichloroethylene (p,p'-DDE): 2.07 (95 % CI 1.08, 3.97), and trans-Nonachlor: 2.55 (95 % CI 0.93, 7.02). The OR for sum 35 PCBs was 1.22 (95 % CI: 0.58-2.57). To complement the main analyses, we used BKMR and g-computation models to evaluate 12 mixture components including 4 TEQs, 2 PCB subsets and 6 pesticides; suggestive positive associations for the joint effect of the mixture analyses resulted in ORs of 1.40 (95% CI: -1.13, 3.93) for BKMR and 1.32 (95% CI: -1.12, 3.76) for g-computation. The mixture analyses provide further support to previously observed associations of trans-Nonachlor, p,p'- DDE, PCDD TEQ and some PCB groups with diabetes.
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Affiliation(s)
- M Pavuk
- Agency for Toxic Substances and Disease Registry (ATSDR), Centers for Disease Control and Prevention (CDC), Atlanta, GA, United States of America
| | - P F Rosenbaum
- SUNY Upstate Medical University, Syracuse, NY, United States of America.
| | - M D Lewin
- Agency for Toxic Substances and Disease Registry (ATSDR), Centers for Disease Control and Prevention (CDC), Atlanta, GA, United States of America
| | - T C Serio
- Agency for Toxic Substances and Disease Registry (ATSDR), Centers for Disease Control and Prevention (CDC), Atlanta, GA, United States of America; ATSDR/CDC, Atlanta, GA, United States of America
| | - P Rago
- ATSDR/CDC, Atlanta, GA, United States of America
| | - M C Cave
- University of Louisville, Louisville, KY, United States of America
| | - L S Birnbaum
- NIEHS, Research Triangle Park, NC, United States of America
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Lafranconi M, Anderson J, Budinsky R, Corey L, Forsberg N, Klapacz J, LeBaron MJ. An integrated assessment of the 1,4-dioxane cancer mode of action and threshold response in rodents. Regul Toxicol Pharmacol 2023:105428. [PMID: 37277058 DOI: 10.1016/j.yrtph.2023.105428] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 05/19/2023] [Accepted: 06/02/2023] [Indexed: 06/07/2023]
Abstract
1,4-Dioxane is an environmental contaminant that has been shown to cause cancer in rodents after chronic high dose exposures. We reviewed and integrated information from recently published studies to update our understanding of the cancer mode of action of 1,4-dioxane. Tumor development in rodents from exposure to high doses of 1,4-dioxane is preceded by pre-neoplastic events including increased hepatic genomic signaling activity related to mitogenesis, elevation of Cyp2E1 activity and oxidative stress leading to genotoxicity and cytotoxicity. These events are followed by regenerative repair and proliferation and eventual development of tumors. Importantly, these events occur at doses that exceed the metabolic clearance of absorbed 1,4-dioxane in rats and mice resulting in elevated systemic levels of parent 1,4-dioxane. Consistent with previous reviews, we found no evidence of direct mutagenicity from exposure to 1,4-dioxane. We also found no evidence of CAR/PXR, AhR or PPARα activation resulting from exposure to 1,4-dioxane. This integrated assessment supports a cancer mode of action that is dependent on exceeding the metabolic clearance of absorbed 1,4-dioxane, direct mitogenesis, elevation of Cyp2E1 activity and oxidative stress leading to genotoxicity and cytotoxicity followed by sustained proliferation driven by regenerative repair and progression of heritable lesions to tumor development.
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Gong Y, Yang D, Barrett H, Sun J, Peng H. Building the Environmental Chemical-Protein Interaction Network (eCPIN): An Exposome-Wide Strategy for Bioactive Chemical Contaminant Identification. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:3486-3495. [PMID: 36827403 DOI: 10.1021/acs.est.2c02751] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Although advancements in nontargeted analysis have made it possible to detect hundreds of chemical contaminants in a single run, the current environmental toxicology approaches lag behind, precluding the transition from analytical chemistry efforts to health risk assessment. We herein highlighted a recently developed "top-down" bioanalytical method, protein Affinity Purification with Nontargeted Analysis (APNA), to screen for bioactive chemical contaminants at the "exposome-wide" level. To achieve this, a tagged functional protein is employed as a "bait" to directly isolate bioactive chemical contaminants from environmental mixtures, which are further identified by nontargeted analysis. Advantages of this protein-guided approach, including the discovery of new bioactive ligands as well as new protein targets for known chemical contaminants, were highlighted by several case studies. Encouraged by these successful applications, we further proposed a framework, i.e., the environmental Chemical-Protein Interaction Network (eCPIN), to construct a complete map of the 7 billion binary interactions between all chemical contaminants (>350,000) and human proteins (∼20,000) via APNA. The eCPIN could be established in three stages through strategically prioritizing the ∼20,000 human proteins, such as focusing on the 48 nuclear receptors (e.g., thyroid hormone receptors) in the first stage. The eCPIN will provide an unprecedented throughput for screening bioactive chemical contaminants at the exposome-wide level and facilitate the identification of molecular initiating events at the proteome-wide level.
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Affiliation(s)
- Yufeng Gong
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Diwen Yang
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Holly Barrett
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Jianxian Sun
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Hui Peng
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
- School of the Environment, University of Toronto, Toronto, Ontario M5S 3H6, Canada
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Yan L, Messner CJ, Tian M, Gou X, Suter-Dick L, Zhang X. Evaluation of dioxin induced transcriptomic responses in a 3D human liver microtissue model. ENVIRONMENTAL RESEARCH 2022; 210:112906. [PMID: 35181307 DOI: 10.1016/j.envres.2022.112906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 01/27/2022] [Accepted: 02/04/2022] [Indexed: 06/14/2023]
Abstract
Three-dimensional human liver microtissue model provides a promising method for predicting the human hepatotoxicity of environmental chemicals. However, the dynamics of transcriptional responses of 3D human liver microtissue model to dioxins exposure remain unclear. Herein, time-series transcriptomic analysis was used to characterize modulation of gene expression over 14 days in 3D human liver microtissues exposed to 2,3,7,8-tetra-chlorodibenzo-p-dioxin (TCDD, 31 nM, 10 ng/ml). Changes in gene expression and modulation of biological pathways were evaluated at several time points. The results showed that microtissues stably expressed genes related to toxicological pathways (e.g. highly of genes involved in external stimuli and maintenance of cell homeostasis pathways) during the 14-day culture period. Furthermore, a weekly phenomenon pattern was observed for the number of the differentially expressed genes in microtissues exposed to TCDD at each time point. TCDD led to an induction of genes involved in cell cycle regulation at day three. Metabolic pathways were the main significantly induced pathways during the subsequent days, with the immune/inflammatory response enriched on the fifth day, and the cellular response to DNA damage was identified at the end of the exposure. Finally, relevant transcription patterns identified in microtissues were compared with published data on rodent and human cell-line studies to elucidate potential species-specific responses to TCDD over time. Cell development and cytochrome P450 pathway were mainly affected after a 3-day exposure, with the DNA damage response identified at the end of exposure in the human microtissue system but not in mouse/rat primary hepatocytes models. Overall, the 3D human liver microtissue model is a valuable tool to predict the toxic effects of environmental chemicals with a relatively long exposure.
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Affiliation(s)
- Lu Yan
- State Key Laboratory of Pollution Control & Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China
| | - Catherine Jane Messner
- University of Applied Sciences Northwestern Switzerland, School of Life Sciences, Muttenz, Switzerland; Swiss Centre for Applied Human Toxicology (SCAHT), Switzerland
| | - Mingming Tian
- State Key Laboratory of Pollution Control & Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China
| | - Xiao Gou
- State Key Laboratory of Pollution Control & Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China
| | - Laura Suter-Dick
- University of Applied Sciences Northwestern Switzerland, School of Life Sciences, Muttenz, Switzerland; Swiss Centre for Applied Human Toxicology (SCAHT), Switzerland
| | - Xiaowei Zhang
- State Key Laboratory of Pollution Control & Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China.
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Yim G, Minatoya M, Kioumourtzoglou MA, Bellavia A, Weisskopf M, Ikeda-Araki A, Miyashita C, Kishi R. The associations of prenatal exposure to dioxins and polychlorinated biphenyls with neurodevelopment at 6 Months of age: Multi-pollutant approaches. ENVIRONMENTAL RESEARCH 2022; 209:112757. [PMID: 35065939 DOI: 10.1016/j.envres.2022.112757] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 01/14/2022] [Accepted: 01/15/2022] [Indexed: 05/07/2023]
Abstract
BACKGROUND Prenatal exposure to persistent organic pollutants, including polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (DL-PCBs), and nondioxin-like PCBs (NDL-PCBs), has been hypothesized to have a detrimental impact on neurodevelopment. However, the association of prenatal exposure to a dioxin and PCB mixture with neurodevelopment remains largely inconclusive partly because these chemical levels are correlated. OBJECTIVES We aimed to elucidate the association of in utero exposure to a mixture of dioxins and PCBs with neurodevelopment measured at 6 months of age by applying multipollutant methods. METHODS A total of 514 pregnant women were recruited between July 2002 and October 2005 in the Sapporo cohort, Hokkaido Study on Environment and Children's Health. The concentrations of individual dioxin and PCB isomers were assessed in maternal peripheral blood during pregnancy. The mental and psychomotor development of the study participants' infants was evaluated using the Bayley Scales of Infant Development-2nd Edition (n = 259). To determine both the joint and individual associations of prenatal exposure to a dioxin and PCB mixture with infant neurodevelopment, Bayesian kernel machine regression (BKMR) and quantile-based g-computation were employed. RESULTS Suggestive inverse associations were observed between in utero exposure to a dioxin and PCB mixture and infant psychomotor development in both the BKMR and quantile g-computation models. In contrast, we found no association of a dioxin and PCB mixture with mental development. When group-specific posterior inclusion probabilities were estimated, BKMR suggested prenatal exposure to mono-ortho PCBs as the more important contributing factors to early psychomotor development compared with the other dioxin or PCB groups. No evidence of nonlinear exposure-outcome relationships or interactions among the chemical mixtures was detected. CONCLUSIONS Applying the two complementary statistical methods for chemical mixture analysis, we demonstrated limited evidence of inverse associations of prenatal exposure to dioxins and PCBs with infant psychomotor development.
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Affiliation(s)
- Gyeyoon Yim
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Machiko Minatoya
- Hokkaido University Center for Environmental and Health Sciences, Kita 12, Nishi 7, Kita-ku, Sapporo, 060-0812, Japan
| | | | - Andrea Bellavia
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Marc Weisskopf
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Atsuko Ikeda-Araki
- Hokkaido University Center for Environmental and Health Sciences, Kita 12, Nishi 7, Kita-ku, Sapporo, 060-0812, Japan; Hokkaido University Faculty of Health Sciences, Kita 12, Nishi 5, Kita-ku, Sapporo, 060-0812, Japan
| | - Chihiro Miyashita
- Hokkaido University Center for Environmental and Health Sciences, Kita 12, Nishi 7, Kita-ku, Sapporo, 060-0812, Japan
| | - Reiko Kishi
- Hokkaido University Center for Environmental and Health Sciences, Kita 12, Nishi 7, Kita-ku, Sapporo, 060-0812, Japan.
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13
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Hilton GM, Adcock C, Akerman G, Baldassari J, Battalora M, Casey W, Clippinger AJ, Cope R, Goetz A, Hayes AW, Papineni S, Peffer RC, Ramsingh D, Williamson Riffle B, Sanches da Rocha M, Ryan N, Scollon E, Visconti N, Wolf DC, Yan Z, Lowit A. Rethinking chronic toxicity and carcinogenicity assessment for agrochemicals project (ReCAAP): A reporting framework to support a weight of evidence safety assessment without long-term rodent bioassays. Regul Toxicol Pharmacol 2022; 131:105160. [PMID: 35311659 DOI: 10.1016/j.yrtph.2022.105160] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 03/07/2022] [Accepted: 03/14/2022] [Indexed: 11/17/2022]
Abstract
Rodent cancer bioassays have been long-required studies for regulatory assessment of human cancer hazard and risk. These studies use hundreds of animals, are resource intensive, and certain aspects of these studies have limited human relevance. The past 10 years have seen an exponential growth of new technologies with the potential to effectively evaluate human cancer hazard and risk while reducing, refining, or replacing animal use. To streamline and facilitate uptake of new technologies, a workgroup comprised of scientists from government, academia, non-governmental organizations, and industry stakeholders developed a framework for waiver rationales of rodent cancer bioassays for consideration in agrochemical safety assessment. The workgroup used an iterative approach, incorporating regulatory agency feedback, and identifying critical information to be considered in a risk assessment-based weight of evidence determination of the need for rodent cancer bioassays. The reporting framework described herein was developed to support a chronic toxicity and carcinogenicity study waiver rationale, which includes information on use pattern(s), exposure scenario(s), pesticidal mode-of-action, physicochemical properties, metabolism, toxicokinetics, toxicological data including mechanistic data, and chemical read-across from similar registered pesticides. The framework could also be applied to endpoints other than chronic toxicity and carcinogenicity, and for chemicals other than agrochemicals.
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Affiliation(s)
- Gina M Hilton
- PETA Science Consortium International e.V., Stuttgart, Germany.
| | - Catherine Adcock
- Health Canada, Pest Management Regulatory Agency, Ottawa, Ontario, Canada
| | - Gregory Akerman
- United States Environmental Protection Agency, Office of Pesticide Programs, Washington DC, USA
| | | | | | - Warren Casey
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | | | - Rhian Cope
- Australian Pesticides and Veterinary Medicines Authority, Armidale, New South Wales, Australia
| | - Amber Goetz
- Syngenta Crop Protection, LLC, Greensboro, NC, USA
| | - A Wallace Hayes
- University of South Florida College of Public Health, Tampa, FL, USA
| | | | | | - Deborah Ramsingh
- Health Canada, Pest Management Regulatory Agency, Ottawa, Ontario, Canada
| | | | | | - Natalia Ryan
- Syngenta Crop Protection, LLC, Greensboro, NC, USA
| | | | | | | | | | - Anna Lowit
- United States Environmental Protection Agency, Office of Pesticide Programs, Washington DC, USA
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14
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Felter SP, Bhat VS, Botham PA, Bussard DA, Casey W, Hayes AW, Hilton GM, Magurany KA, Sauer UG, Ohanian EV. Assessing chemical carcinogenicity: hazard identification, classification, and risk assessment. Insight from a Toxicology Forum state-of-the-science workshop. Crit Rev Toxicol 2022; 51:653-694. [DOI: 10.1080/10408444.2021.2003295] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
| | | | | | - David A. Bussard
- U.S. Environmental Protection Agency, Office of the Science Advisor, Policy and Engagement, Washington, DC, USA
| | - Warren Casey
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - A. Wallace Hayes
- University of South Florida College of Public Health, Tampa, FL, USA
| | - Gina M. Hilton
- PETA Science Consortium International e.V., Stuttgart, Germany
| | | | | | - Edward V. Ohanian
- United States Environmental Protection Agency, Office of Water, Washington, DC, USA
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15
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Rusyn I, Arzuaga X, Cattley RC, Christopher Corton J, Ferguson SS, Godoy P, Guyton KZ, Kaplowitz N, Khetani SR, Roberts R, Roth RA, Smith MT. Key Characteristics of Human Hepatotoxicants as a Basis for Identification and Characterization of the Causes of Liver Toxicity. Hepatology 2021; 74:3486-3496. [PMID: 34105804 PMCID: PMC8901129 DOI: 10.1002/hep.31999] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 05/05/2021] [Accepted: 06/07/2021] [Indexed: 12/13/2022]
Abstract
Hazard identification regarding adverse effects on the liver is a critical step in safety evaluations of drugs and other chemicals. Current testing paradigms for hepatotoxicity rely heavily on preclinical studies in animals and human data (epidemiology and clinical trials). Mechanistic understanding of the molecular and cellular pathways that may cause or exacerbate hepatotoxicity is well advanced and holds promise for identification of hepatotoxicants. One of the challenges in translating mechanistic evidence into robust decisions about potential hepatotoxicity is the lack of a systematic approach to integrate these data to help identify liver toxicity hazards. Recently, marked improvements were achieved in the practice of hazard identification of carcinogens, female and male reproductive toxicants, and endocrine disrupting chemicals using the key characteristics approach. Here, we describe the methods by which key characteristics of human hepatotoxicants were identified and provide examples for how they could be used to systematically identify, organize, and use mechanistic data when identifying hepatotoxicants.
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Affiliation(s)
- Ivan Rusyn
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, USA
| | - Xabier Arzuaga
- Center for Public Health and Environmental Assessment, Environmental Protection Agency, Washington, DC, USA
| | | | - J. Christopher Corton
- Center for Computational Toxicology and Exposure, Environmental Protection Agency, Durham, NC, USA
| | - Stephen S. Ferguson
- National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, Durham, NC, USA
| | - Patricio Godoy
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | - Kathryn Z. Guyton
- Monographs Programme, International Agency for Research on Cancer, Lyon, France
| | - Neil Kaplowitz
- Research Center for Liver Disease, University of Southern California, Los Angeles, CA, USA
| | - Salman R. Khetani
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Ruth Roberts
- ApconiX, Alderley Edge, United Kingdom
- School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Robert A. Roth
- Department of Pharmacology and Toxicology, Michigan State University, East Lancing, MI, USA
| | - Martyn T. Smith
- Division of Environmental Health Sciences, University of California Berkeley, Berkeley, CA, USA
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16
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Herlin M, Sánchez-Pérez I, Esteban J, Korkalainen M, Barber X, Finnilä MAJ, Hamscher G, Joseph B, Viluksela M, Håkansson H. Bone toxicity induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and the retinoid system: A causality analysis anchored in osteoblast gene expression and mouse data. Reprod Toxicol 2021; 105:25-43. [PMID: 34363983 DOI: 10.1016/j.reprotox.2021.07.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 07/16/2021] [Accepted: 07/30/2021] [Indexed: 12/18/2022]
Abstract
Dioxin exposures impact on bone quality and osteoblast differentiation, as well as retinoic acid metabolism and signaling. In this study we analyzed associations between increased circulating retinol concentrations and altered bone mineral density in a mouse model following oral exposure to 2,3,7,8-tetrachlordibenzo-p-dioxin (TCDD). Additionally, effects of TCDD on differentiation marker genes and genes involved with retinoic acid metabolism were analysed in an osteoblast cell model followed by benchmark dose-response analyses of the gene expression data. Study results show that the increased trabecular and decreased cortical bone mineral density in the mouse model following TCDD exposure are associated with increased circulating retinol concentrations. Also, TCDD disrupted the expression of genes involved in osteoblast differentiation and retinoic acid synthesis, degradation, and nuclear translocation in directions compatible with increasing cellular retinoic acid levels. Further evaluation of the obtained results in relation to previously published data by the use of mode-of-action and weight-of-evidence inspired analytical approaches strengthened the evidence that TCDD-induced bone and retinoid system changes are causally related and compatible with an endocrine disruption mode of action.
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Affiliation(s)
- Maria Herlin
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
| | - Ismael Sánchez-Pérez
- Instituto de Bioingeniería, Universidad Miguel Hernández de Elche, Elche, Alicante, Spain.
| | - Javier Esteban
- Instituto de Bioingeniería, Universidad Miguel Hernández de Elche, Elche, Alicante, Spain.
| | - Merja Korkalainen
- Environmental Health Unit, Finnish Institute for Health and Welfare (THL), Kuopio, Finland.
| | - Xavier Barber
- Centro de Investigación Operativa, Universidad Miguel Hernández, Elche, Alicante, Spain.
| | - Mikko A J Finnilä
- Research Unit of Medical Imaging, Physics, and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland.
| | - Gerd Hamscher
- Institute of Food Chemistry and Food Biotechnology, Justus Liebig University Giessen, 10 Giessen, Germany.
| | - Bertrand Joseph
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
| | - Matti Viluksela
- Environmental Health Unit, Finnish Institute for Health and Welfare (THL), Kuopio, Finland; School of Pharmacy (Toxicology) and Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland.
| | - Helen Håkansson
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
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17
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Santos C, Martinez CBDR. Multixenobiotic resistance mechanism: Organ-specific characteristics in the fish Prochilodus lineatus and its role as a protection against genotoxic agents. Comp Biochem Physiol C Toxicol Pharmacol 2021; 243:108996. [PMID: 33548546 DOI: 10.1016/j.cbpc.2021.108996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 01/06/2021] [Accepted: 01/27/2021] [Indexed: 11/17/2022]
Abstract
The multixenobiotic resistance mechanism (MXR) can decrease intracellular genotoxic pressure through the efflux of compounds out of the cell. Thus, this work presents a temporal approach to evaluate the MXR activity and the occurrence of genotoxic damage in different organs of the fish Prochilodus lineatus after an intraperitoneal injection of benzo[a]pyrene (B[a]P). Although the liver and brain demonstrated rapid MXR induction (6 h), the occurrence of DNA damage was not prevented. However, these organs presented some return to DNA integrity after MXR activity. The kidney demonstrated the slowest response in the MXR induction (24 h), which may be related to the preferential excretion of B[a]P metabolites by this route. Moreover, the kidney MXR reduction at 96 h may be related to its role in the excretion of metabolites from all other metabolizing organs. The gills did not appear to play an essential role in xenobiotics efflux; however, their participation in biotransformation is exhibited through the occurrence of DNA damage. The integrated response of the organs in the dynamics for the maintenance of the organism integrity could be promoted by the circulation of the xenobiotic through the bloodstream, which corroborates the increase in the DNA damage in the erythrocytes at 6 h. Therefore, the ability to induce MXR was linked to the preservation of DNA integrity in the presence of B[a]P, since MXR acts to avoid the accumulation of xenobiotics inside the cell.
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Affiliation(s)
- Caroline Santos
- Department of Physiological Sciences, State University of Londrina (UEL), Londrina, Paraná, Brazil
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18
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Guzmán A, Encina G, Fernández de Henestrosa AR, Vila C, Tortajada A, Marín AP. Twenty six-week repeat dose oral rat toxicity study of cizolirtine, a substance-P and calcitonin gene-related peptide release modulator. Regul Toxicol Pharmacol 2021; 122:104916. [PMID: 33711392 DOI: 10.1016/j.yrtph.2021.104916] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 03/01/2021] [Accepted: 03/03/2021] [Indexed: 02/05/2023]
Abstract
Cizolirtine, a substance-P and calcitonin gene-related peptide release modulator developed for the treatment of pain and urinary incontinence, was orally administered for 26-weeks to rats at dosages of 20, 60 and 200 mg/kg/day. Clinical signs were limited to post-dosing salivation and brown staining on head and muzzle. There were slight decreases in bodyweight gain and slight increases in water consumption among cizolirtine-treated animals. Slight increases in plasma alkaline phosphatase activity, and cholesterol and phospholipid concentrations were observed in mid- and/or high-dose animals. Low urinary volume, pH and sodium and potassium outputs were observed after 12-weeks, and low urinary pH, low sodium and high potassium outputs at end of treatment. Increased relative (to bodyweight) liver weight was observed in high-dose animals. Treated males and high-dose females showed a dose-related increase in the incidence and severity of periacinar hepatocytic hypertrophy and midzonal/periacinar hepatocytic fat vacuolization. Increased incidences of hepatic clear cell foci were observed in all cizolirtine-treated male groups and, to a lesser extent, in treated females. Ovaries of treated females showed a dose-dependent increased incidence of absent corpora lutea and, occasionally, follicular cysts. The dosages of 20 and 60 mg/kg/day were considered as the No-Observed-Adverse-Effect Levels for males and females, respectively.
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Affiliation(s)
- Antonio Guzmán
- Toxicology Department, Welab Barcelona and Toxicology Department Esteve Pharmaceuticals, Spain.
| | - Gregorio Encina
- Development PK & Bioanalysis Department WeLab Barcelona and Development PK & Bioanalysis Department, Esteve Pharmaceuticals, Spain
| | | | - Cristina Vila
- Toxicology Department, Welab Barcelona and Toxicology Department Esteve Pharmaceuticals, Spain
| | - Araceli Tortajada
- Toxicology Department, Welab Barcelona and Toxicology Department Esteve Pharmaceuticals, Spain
| | - Ana-Paz Marín
- Toxicology Department, Welab Barcelona and Toxicology Department Esteve Pharmaceuticals, Spain
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19
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Santos C, Bueno Dos Reis Martinez C. Biotransformation in the fish Prochilodus lineatus: An organ-specific approach to cyp1a gene expression and biochemical activity. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2020; 80:103467. [PMID: 32791344 DOI: 10.1016/j.etap.2020.103467] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 07/09/2020] [Accepted: 08/03/2020] [Indexed: 06/11/2023]
Abstract
The biotransformation ability of the organism is the result of organ-specific responses. This paper presents a molecular and biochemical approach to elucidate the biotransformation mechanisms in different organs of Prochilodus lineatus induced at 6, 24, and 96 h after a benzo[a]pyrene (B[a]P) injection. The induction in cyp1a transcription showed an organ-specific intensity at every tested time time. The EROD (ethoxyresorufin-O-deethylase) activity increased rapidly (6 h) in the liver and the kidney; the gills and the brain showed an increase at 24 h; and the gills demonstrated the highest activity among all the organs tested. There was no increase in glutathione S-transferase (GST) activity or lipoperoxidation. The decreased hepatic glutathione content (GSH) may be due to its role as an antioxidant. B[a]P was detected in the bile, confirming the xenobiotic efflux from the metabolizing organs. The gills, liver, brain, and kidney of P. lineatus presented an integrated mechanism to deal with the xenobiotic biotransformation.
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Affiliation(s)
- Caroline Santos
- Department of Physiological Sciences, State University of Londrina, Rod. Celso Garcia Cid, km 380, Londrina, Parana, 86057-970, Brazil
| | - Claudia Bueno Dos Reis Martinez
- Department of Physiological Sciences, State University of Londrina, Rod. Celso Garcia Cid, km 380, Londrina, Parana, 86057-970, Brazil.
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20
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Corton JC, Hill T, Sutherland JJ, Stevens JL, Rooney J. A Set of Six Gene Expression Biomarkers Identify Rat Liver Tumorigens in Short-term Assays. Toxicol Sci 2020; 177:11-26. [PMID: 32603430 PMCID: PMC8026143 DOI: 10.1093/toxsci/kfaa101] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Chemical-induced liver cancer occurs in rodents through well-characterized adverse outcome pathways. We hypothesized that measurement of the 6 most common molecular initiating events (MIEs) in liver cancer adverse outcome pathways in short-term assays using only gene expression will allow early identification of chemicals and their associated doses that are likely to be tumorigenic in the liver in 2-year bioassays. We tested this hypothesis using transcript data from a rat liver microarray compendium consisting of 2013 comparisons of 146 chemicals administered at doses with previously established effects on rat liver tumor induction. Five MIEs were measured using previously characterized gene expression biomarkers composed of gene sets predictive for genotoxicity and activation of 1 or more xenobiotic receptors (aryl hydrocarbon receptor, constitutive activated receptor, estrogen receptor, and peroxisome proliferator-activated receptor α). Because chronic injury can be important in tumorigenesis, we also developed a biomarker for cytotoxicity that had a 96% balanced accuracy. Characterization of the genes in each biomarker set using the unsupervised TXG-MAP network model demonstrated that the genes were associated with distinct functional coexpression modules. Using the Toxicological Priority Index to rank chemicals based on their ability to activate the MIEs showed that chemicals administered at tumorigenic doses clearly gave the highest ranked scores. Balanced accuracies using thresholds derived from either TG-GATES or DrugMatrix data sets to predict tumorigenicity in independent sets of chemicals were up to 93%. These results show that a MIE-directed approach using only gene expression biomarkers could be used in short-term assays to identify chemicals and their doses that cause tumors.
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Affiliation(s)
- J Christopher Corton
- Center for Computational Toxicology and Exposure, U.S. Environmental Protection Agency (EPA), Research Triangle Park, North Carolina
| | - Thomas Hill
- Center for Computational Toxicology and Exposure, U.S. Environmental Protection Agency (EPA), Research Triangle Park, North Carolina
- Oak Ridge Institute for Science and Education (ORISE)
| | | | - James L Stevens
- Indiana Biosciences Research Institute, Indianapolis, Indiana
- Paradox Found LLC, Apex, North Carolina
| | - John Rooney
- Center for Computational Toxicology and Exposure, U.S. Environmental Protection Agency (EPA), Research Triangle Park, North Carolina
- Oak Ridge Institute for Science and Education (ORISE)
- Integrated Lab Services, Research Triangle Park, NC 27560
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21
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Constitutive androstane receptor (CAR) mediates dieldrin-induced liver tumorigenesis in mouse. Arch Toxicol 2020; 94:2873-2884. [PMID: 32435917 DOI: 10.1007/s00204-020-02781-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Accepted: 05/07/2020] [Indexed: 10/25/2022]
Abstract
Dieldrin has been shown to induce liver tumors selectively in mice. Although the exact mechanism is not fully understood, previous studies from our laboratory and others have shown that dieldrin induced liver tumors in mice through a non-genotoxic mechanism acting on tumor promotion stage. Two studies were performed to examine the role of nuclear receptor activation as a possible mode of action (MOA) for dieldrin-induced mouse liver tumors. In the initial study, male C57BL/6 mice (6- to 8-week old) were treated with dieldrin in diet (10 ppm) for 7, 14, and 28 days. Phenobarbital (PB), beta-naphthoflavone (BNF) and Di (2-ethylhexyl) phthalate (DEHP) were included as positive controls in this study for evaluating the involvement of CAR (constitutive androstane receptor), AhR (aryl hydrocarbon receptor) or PPARα (peroxisome proliferator activated receptor alpha) in the MOA of dieldrin hepatocarcinogenesis. A significant increase in hepatocyte DNA synthesis (BrdU incorporation) was seen in treated mice compared with the untreated controls. Analysis of the expression of the nuclear receptor responsive genes revealed that dieldrin induced a significant increase in the expression of genes specific to CAR activation (Cyp2b10, up to 400- to 2700-fold) and PXR activation (Cyp3a11, up to 5- to 11-fold) over untreated controls. The AhR target genes Cyp1a1 and Cyp1a2 were also slightly induced (2.0- to 3.7-fold and 1.7- to 2.8-fold, respectively). PPARα activation was not seen in the liver following dieldrin treatment. In addition, consistent with previous studies in our lab, treatment with dieldrin produced significant elevation in the hepatic oxidative stress. In a subsequent study using CAR, PXR, and CAR/PXR knockout mice, we confirmed that the dieldrin-induced liver effects in mouse were only mediated by the activation of CAR receptor. Based on these findings, we propose that dieldrin induced liver tumors in mice through a nuclear receptor CAR-mediated mode of action. The previously observed oxidative stress/damage may be an associated or modifying factor in the process of dieldrin-induced liver tumor formation subsequent to the CAR activation.
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22
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van der Ven LTM, Rorije E, Sprong RC, Zink D, Derr R, Hendriks G, Loo LH, Luijten M. A Case Study with Triazole Fungicides to Explore Practical Application of Next-Generation Hazard Assessment Methods for Human Health. Chem Res Toxicol 2020; 33:834-848. [PMID: 32041405 DOI: 10.1021/acs.chemrestox.9b00484] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The ongoing developments in chemical risk assessment have led to new concepts building on integration of sophisticated nonanimal models for hazard characterization. Here we explore a pragmatic approach for implementing such concepts, using a case study of three triazole fungicides, namely, flusilazole, propiconazole, and cyproconazole. The strategy applied starts with evaluating the overall level of concern by comparing exposure estimates to toxicological potential, followed by a combination of in silico tools and literature-derived high-throughput screening assays and computational elaborations to obtain insight into potential toxicological mechanisms and targets in the organism. Additionally, some targeted in vitro tests were evaluated for their utility to confirm suspected mechanisms of toxicity and to generate points of departure. Toxicological mechanisms instead of the current "end point-by-end point" approach should guide the selection of methods and assays that constitute a toolbox for next-generation risk assessment. Comparison of the obtained in silico and in vitro results with data from traditional in vivo testing revealed that, overall, nonanimal methods for hazard identification can produce adequate qualitative hazard information for risk assessment. Follow-up studies are needed to further refine the proposed approach, including the composition of the toolbox, toxicokinetics models, and models for exposure assessment.
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23
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Rooney JP, Oshida K, Kumar R, Baldwin WS, Corton JC. Chemical Activation of the Constitutive Androstane Receptor Leads to Activation of Oxidant-Induced Nrf2. Toxicol Sci 2019; 167:172-189. [PMID: 30203046 DOI: 10.1093/toxsci/kfy231] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Exposure to environmentally relevant chemicals that activate the xenobiotic receptors aryl hydrocarbon receptor (AhR), constitutive androstane receptor (CAR), and peroxisome proliferator-activated receptor alpha (PPARα) in rodent test systems often leads to increases in oxidative stress (OS) that contributes to liver cancer induction. We hypothesized that activation of the oxidant-induced transcription factor Nrf2 could be used as a surrogate endpoint for increases in OS. We examined the relationships between activation of xenobiotic receptors and Nrf2 using previously characterized gene expression biomarkers that accurately predict modulation. Using a correlation approach (Running Fisher Test), the biomarkers were compared with microarray profiles in a mouse liver gene expression compendium. Out of the 163 chemicals examined, 47% from 53 studies activated Nrf2. We found consistent coupling between CAR and Nrf2 activation. Out of the 41 chemicals from 32 studies that activated CAR, 90% also activated Nrf2. CAR was activated earlier and at lower doses than Nrf2, indicating CAR activation preceded Nrf2 activation. Nrf2 activation by 2 CAR activators was abolished in CAR-null mice. We hypothesized that Nrf2 is activated by reactive oxygen species from the increased activity of enzymes encoded by Cyp2b family members. However, Nrf2 was similarly activated in the livers of both TCPOBOP-treated wild-type and Cyp2b9/10/13-null mice. This study provides evidence that Nrf2 activation (1) often occurs after exposure to xenobiotic chemicals, (2) is tightly linked to activation of CAR, and (3) does not require induction of 3 Cyp2b genes secondary to CAR activation.
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Affiliation(s)
- John P Rooney
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711.,Oak Ridge Institute for Science and Education (ORISE) participant at the National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina
| | - Keiyu Oshida
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711.,Toray Industries, Inc, Kanagawa, Japan
| | - Ramiya Kumar
- Environmental Toxicology Program and Biological Sciences Department, Clemson University, Clemson, South Carolina 29634
| | - William S Baldwin
- Environmental Toxicology Program and Biological Sciences Department, Clemson University, Clemson, South Carolina 29634
| | - J Christopher Corton
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711
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Effects of astrocyte conditioned medium on neuronal AChE expression upon 2,3,7,8-tetrachlorodibenzo-p-dioxin exposure. Chem Biol Interact 2019; 309:108686. [DOI: 10.1016/j.cbi.2019.05.052] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 04/24/2019] [Accepted: 05/29/2019] [Indexed: 12/21/2022]
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25
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Knutsen HK, Alexander J, Barregård L, Bignami M, Brüschweiler B, Ceccatelli S, Cottrill B, Dinovi M, Edler L, Grasl-Kraupp B, Hogstrand C, Nebbia CS, Oswald IP, Petersen A, Rose M, Roudot AC, Schwerdtle T, Vleminckx C, Vollmer G, Wallace H, Fürst P, Håkansson H, Halldorsson T, Lundebye AK, Pohjanvirta R, Rylander L, Smith A, van Loveren H, Waalkens-Berendsen I, Zeilmaker M, Binaglia M, Gómez Ruiz JÁ, Horváth Z, Christoph E, Ciccolallo L, Ramos Bordajandi L, Steinkellner H, Hoogenboom LR. Risk for animal and human health related to the presence of dioxins and dioxin-like PCBs in feed and food. EFSA J 2018; 16:e05333. [PMID: 32625737 PMCID: PMC7009407 DOI: 10.2903/j.efsa.2018.5333] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The European Commission asked EFSA for a scientific opinion on the risks for animal and human health related to the presence of dioxins (PCDD/Fs) and DL-PCBs in feed and food. The data from experimental animal and epidemiological studies were reviewed and it was decided to base the human risk assessment on effects observed in humans and to use animal data as supportive evidence. The critical effect was on semen quality, following pre- and postnatal exposure. The critical study showed a NOAEL of 7.0 pg WHO2005-TEQ/g fat in blood sampled at age 9 years based on PCDD/F-TEQs. No association was observed when including DL-PCB-TEQs. Using toxicokinetic modelling and taking into account the exposure from breastfeeding and a twofold higher intake during childhood, it was estimated that daily exposure in adolescents and adults should be below 0.25 pg TEQ/kg bw/day. The CONTAM Panel established a TWI of 2 pg TEQ/kg bw/week. With occurrence and consumption data from European countries, the mean and P95 intake of total TEQ by Adolescents, Adults, Elderly and Very Elderly varied between, respectively, 2.1 to 10.5, and 5.3 to 30.4 pg TEQ/kg bw/week, implying a considerable exceedance of the TWI. Toddlers and Other Children showed a higher exposure than older age groups, but this was accounted for when deriving the TWI. Exposure to PCDD/F-TEQ only was on average 2.4- and 2.7-fold lower for mean and P95 exposure than for total TEQ. PCDD/Fs and DL-PCBs are transferred to milk and eggs, and accumulate in fatty tissues and liver. Transfer rates and bioconcentration factors were identified for various species. The CONTAM Panel was not able to identify reference values in most farm and companion animals with the exception of NOAELs for mink, chicken and some fish species. The estimated exposure from feed for these species does not imply a risk.
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Rooney J, Hill T, Qin C, Sistare FD, Corton JC. Adverse outcome pathway-driven identification of rat liver tumorigens in short-term assays. Toxicol Appl Pharmacol 2018; 356:99-113. [DOI: 10.1016/j.taap.2018.07.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 07/12/2018] [Accepted: 07/20/2018] [Indexed: 02/07/2023]
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27
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Rooney J, Oshida K, Vasani N, Vallanat B, Ryan N, Chorley BN, Wang X, Bell DA, Wu KC, Aleksunes LM, Klaassen CD, Kensler TW, Corton JC. Activation of Nrf2 in the liver is associated with stress resistance mediated by suppression of the growth hormone-regulated STAT5b transcription factor. PLoS One 2018; 13:e0200004. [PMID: 30114225 PMCID: PMC6095522 DOI: 10.1371/journal.pone.0200004] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 06/15/2018] [Indexed: 12/30/2022] Open
Abstract
The transcription factor Nrf2 (encoded by Nfe2l2) induces expression of numerous detoxifying and antioxidant genes in response to oxidative stress. The cytoplasmic protein Keap1 interacts with and represses Nrf2 function. Computational approaches were developed to identify factors that modulate Nrf2 in a mouse liver gene expression compendium. Forty-eight Nrf2 biomarker genes were identified using profiles from the livers of mice in which Nrf2 was activated genetically in Keap1-null mice or chemically by a potent activator of Nrf2 signaling. The rank-based Running Fisher statistical test was used to determine the correlation between the Nrf2 biomarker genes and a test set of 81 profiles with known Nrf2 activation status demonstrating a balanced accuracy of 96%. For a large number of factors examined in the compendium, we found consistent relationships between activation of Nrf2 and feminization of the liver transcriptome through suppression of the male-specific growth hormone (GH)-regulated transcription factor STAT5b. The livers of female mice exhibited higher Nrf2 activation than male mice in untreated or chemical-treated conditions. In male mice, Nrf2 was activated by treatment with ethinyl estradiol, whereas in female mice, Nrf2 was suppressed by treatment with testosterone. Nrf2 was activated in 5 models of disrupted GH signaling containing mutations in Pit1, Prop1, Ghrh, Ghrhr, and Ghr. Out of 59 chemical treatments that activated Nrf2, 36 exhibited STAT5b suppression in the male liver. The Nrf2-STAT5b coupling was absent in in vitro comparisons of chemical treatments. Treatment of male and female mice with 11 chemicals that induce oxidative stress led to activation of Nrf2 to greater extents in females than males. The enhanced basal and inducible levels of Nrf2 activation in females relative to males provides a molecular explanation for the greater resistance often seen in females vs. males to age-dependent diseases and chemical-induced toxicity.
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Affiliation(s)
- John Rooney
- NHEERL, US-EPA, Research Triangle Park, NC, United States of America
| | - Keiyu Oshida
- NHEERL, US-EPA, Research Triangle Park, NC, United States of America
| | - Naresh Vasani
- NHEERL, US-EPA, Research Triangle Park, NC, United States of America
| | - Beena Vallanat
- NHEERL, US-EPA, Research Triangle Park, NC, United States of America
| | - Natalia Ryan
- NHEERL, US-EPA, Research Triangle Park, NC, United States of America
| | - Brian N. Chorley
- NHEERL, US-EPA, Research Triangle Park, NC, United States of America
| | - Xuting Wang
- Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC, United States of America
| | - Douglas A. Bell
- Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC, United States of America
| | - Kai C. Wu
- University of Kansas Medical Center, Kansas City, KS, United States of America
| | - Lauren M. Aleksunes
- Rutgers University, Ernest Mario School of Pharmacy, Department of Pharmacology and Toxicology, Piscataway, NJ, United States of America
| | | | - Thomas W. Kensler
- Department of Pharmacology & Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Environmental Health & Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
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28
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Smith AG, Foster JR. The association between chemical-induced porphyria and hepatic cancer. Toxicol Res (Camb) 2018; 7:647-663. [PMID: 30090612 PMCID: PMC6060669 DOI: 10.1039/c8tx00019k] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 04/04/2018] [Indexed: 01/24/2023] Open
Abstract
The haem biosynthetic pathway is of fundamental importance for cellular metabolism both for the erythroid and nonerythroid tissues. There are several genetic variants of the pathway in the human population that cause dysfunction of one or other of the enzymes resulting in porphyrias of varying severity. Serious chronic hepatic and systemic diseases may result. Some of these can be precipitated by exposure to drugs including hormones, barbiturates and antibiotics, as well as alcohol and particular chlorinated aromatic chemicals. In experimental animals some of the steps of this pathway can also be severely disrupted by a variety of environmental chemicals, potential drugs and pesticides, especially in the liver, leading to the accumulation of uroporphyrins derived from the intermediate uroporphyrinogens or protoporphyrin IX, the immediate precursor of haem. With some of these chemicals this also leads to cholestasis and liver cell injury and eventually hepatic tumours. The review evaluates the available evidence linking hepatic porphyria with carcinogenesis in naturally occurring human genetic conditions and in chemically-induced porphyrias in laboratory animals. The existing data showing gender, strain, and species differences in sensitivity to the chemical-induced porphyrias, liver injury and liver tumours are discussed and the role that transgenically altered mouse models have played in defining the varying mechanisms. Finally, the review proposes a novel, unifying hypothesis linking the hepatotoxicity induced by the accumulation of various porphyrins, with the increased risk of developing hepatic cancer as a long term consequence.
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Affiliation(s)
- Andrew G Smith
- MRC Toxicology Unit , Hodgkin Building , University of Leicester , Lancaster Road , Leicester LE2 4UA , UK .
| | - John R Foster
- ToxPath Sciences Ltd , 1 Troutbeck Avenue , Congleton , Cheshire , CW12 4JA , UK
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29
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Minimum datasets to establish a CAR-mediated mode of action for rodent liver tumors. Regul Toxicol Pharmacol 2018; 96:106-120. [DOI: 10.1016/j.yrtph.2018.04.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 03/20/2018] [Accepted: 04/03/2018] [Indexed: 02/06/2023]
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30
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Lake BG. Human relevance of rodent liver tumour formation by constitutive androstane receptor (CAR) activators. Toxicol Res (Camb) 2018; 7:697-717. [PMID: 30090615 PMCID: PMC6060665 DOI: 10.1039/c8tx00008e] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Accepted: 03/09/2018] [Indexed: 01/01/2023] Open
Abstract
A large number of nongenotoxic chemicals have been shown to increase the incidence of liver tumours in rats and/or mice by a mode of action (MOA) involving activation of the constitutive androstane receptor (CAR). Studies with the model CAR activator phenobarbital (PB) and its sodium salt (sodium phenobarbital; NaPB) have demonstrated that the key and associative events for rat and mouse liver tumour formation include CAR activation, increased hepatocyte replicative DNA synthesis (RDS), induction of cytochrome P450 CYP2B subfamily enzymes, liver hypertrophy, increased altered hepatic foci and hepatocellular adenomas/carcinomas. The key species difference between the rat and mouse compared to humans, is that human hepatocytes are refractory to the mitogenic effects of PB/NaPB and other CAR activators. While PB/NaPB and other CAR activators stimulate RDS in rat and mouse hepatocytes in both in vitro and in vivo studies, such compounds do not stimulate RDS in cultured human hepatocytes and in in vivo studies performed in chimeric mice with humanised livers. In terms of species differences in RDS, unlike the rat and mouse, humans are similar to other species such as the Syrian hamster and guinea pig in being nonresponsive to the mitogenic effects of CAR activators. Overall, the MOA for rat and mouse liver tumour formation by PB/NaPB and other CAR activators is considered qualitatively not plausible for humans. This conclusion is supported by data from a number of epidemiological studies, which demonstrate that chronic treatment with PB does not increase the incidence of liver cancer in humans.
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Affiliation(s)
- Brian G Lake
- Centre for Toxicology , Faculty of Health and Medical Sciences , University of Surrey , Guildford , Surrey GU2 7XH , UK .
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31
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Zhou J, Henriquez J, Crawford R, Kaminski N. Suppression of the IgM Response by Aryl Hydrocarbon Receptor Activation in Human Primary B Cells Involves Impairment of Immunoglobulin Secretory Processes. Toxicol Sci 2018; 163:319-329. [PMID: 29462421 PMCID: PMC6659029 DOI: 10.1093/toxsci/kfy036] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Aryl hydrocarbon receptor (AHR) activation by 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD) is well established at suppressing humoral immunity. Previous studies in mouse B cells revealed that decreased IgM production was due to a significant suppression in the mRNA levels of the immunoglobulin M components (IgH, IgJ, and Igκ chains) and subsequent decrease in IgM synthesis. In contrast, the current study shows that activation of AHR in human B cells also results in a significant suppression of the number of IgM-secreting cells, but this is not due to a decrease in the transcription or translation of IgH, IgJ, and Igκ chains. Instead, the reduced humoral response is due to the impairment of IgM secretion. This is further evidenced by an accumulation of intracellular IgM in human B cells, which indicates that activation of AHR alters distinct regulatory pathways in human and mouse B cells leading to the suppressed primary IgM response. Collectively, these results demonstrate that although AHR activation mediates suppression of humoral immune responses across many different animal species, the mechanism of action is not necessarily conserved across species.
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Affiliation(s)
- Jiajun Zhou
- Department of Microbiology and Molecular Genetics
- Institute for Integrative Toxicology
| | - Joseph Henriquez
- Institute for Integrative Toxicology
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan 48824
| | | | - Norbert Kaminski
- Institute for Integrative Toxicology
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan 48824
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32
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Felter SP, Foreman JE, Boobis A, Corton JC, Doi AM, Flowers L, Goodman J, Haber LT, Jacobs A, Klaunig JE, Lynch AM, Moggs J, Pandiri A. Human relevance of rodent liver tumors: Key insights from a Toxicology Forum workshop on nongenotoxic modes of action. Regul Toxicol Pharmacol 2018; 92:1-7. [PMID: 29113941 PMCID: PMC11350555 DOI: 10.1016/j.yrtph.2017.11.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 10/31/2017] [Accepted: 11/02/2017] [Indexed: 12/21/2022]
Abstract
The Toxicology Forum sponsored a workshop in October 2016, on the human relevance of rodent liver tumors occurring via nongenotoxic modes of action (MOAs). The workshop focused on two nuclear receptor-mediated MOAs (Constitutive Androstane Receptor (CAR) and Peroxisome Proliferator Activated Receptor-alpha (PPARα), and on cytotoxicity. The goal of the meeting was to review the state of the science to (1) identify areas of consensus and differences, data gaps and research needs; (2) identify reasons for inconsistencies in current regulatory positions; and (3) consider what data are needed to demonstrate a specific MOA, and when additional research is needed to rule out alternative possibilities. Implications for quantitative risk assessment approaches were discussed, as were implications of not considering MOA and dose in hazard characterization and labeling schemes. Most, but not all, participants considered the CAR and PPARα MOAs as not relevant to humans based on quantitative and qualitative differences. In contrast, cytotoxicity is clearly relevant to humans, but a threshold applies. Questions remain for all three MOAs concerning what data are necessary to determine the MOA and to what extent it is necessary to exclude other MOAs.
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Affiliation(s)
- Susan P Felter
- Procter and Gamble, Central Product Safety, Mason, OH, United States.
| | | | - Alan Boobis
- Department of Medicine, Imperial College London, London, UK
| | - J Christopher Corton
- National Health and Environmental Effects Research Lab, US EPA, Durham, NC, United States
| | - Adriana M Doi
- BASF Corporation, Research Triangle Park, NC, United States
| | - Lynn Flowers
- Office of Science Policy, US EPA, Washington DC, United States
| | - Jay Goodman
- Michigan State University, Dept. Pharmacology and Toxicology, East Lansing, MI, United States
| | - Lynne T Haber
- Risk Science Center, Dept. of Environmental Health, University of Cincinnati, Cincinnati, OH, United States
| | - Abigail Jacobs
- Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, United States
| | | | | | - Jonathan Moggs
- Novartis Institutes for BioMedical Research, Preclinical Safety, Translational Medicine, Basel, Switzerland
| | - Arun Pandiri
- National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC, United States
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33
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Becker RA, Dellarco V, Seed J, Kronenberg JM, Meek B, Foreman J, Palermo C, Kirman C, Linkov I, Schoeny R, Dourson M, Pottenger LH, Manibusan MK. Quantitative weight of evidence to assess confidence in potential modes of action. Regul Toxicol Pharmacol 2017; 86:205-220. [DOI: 10.1016/j.yrtph.2017.02.017] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 02/17/2017] [Accepted: 02/18/2017] [Indexed: 12/31/2022]
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Investigation of the mechanism of triclosan induced mouse liver tumors. Regul Toxicol Pharmacol 2017; 86:137-147. [DOI: 10.1016/j.yrtph.2017.03.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 02/23/2017] [Accepted: 03/02/2017] [Indexed: 02/04/2023]
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35
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Liu S, Kawamoto T, Morita O, Yoshinari K, Honda H. Discriminating between adaptive and carcinogenic liver hypertrophy in rat studies using logistic ridge regression analysis of toxicogenomic data: The mode of action and predictive models. Toxicol Appl Pharmacol 2017; 318:79-87. [PMID: 28108177 DOI: 10.1016/j.taap.2017.01.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 01/11/2017] [Accepted: 01/13/2017] [Indexed: 10/20/2022]
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36
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Wang Z, Li X, Wu Q, Lamb JC, Klaunig JE. Toxaphene-induced mouse liver tumorigenesis is mediated by the constitutive androstane receptor. J Appl Toxicol 2017; 37:967-975. [DOI: 10.1002/jat.3445] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 12/27/2016] [Accepted: 12/27/2016] [Indexed: 11/11/2022]
Affiliation(s)
- Zemin Wang
- Department of Environmental Health; Indiana University Bloomington; IN 47405 USA
| | - Xilin Li
- Department of Environmental Health; Indiana University Bloomington; IN 47405 USA
| | - Qiangen Wu
- Department of Environmental Health; Indiana University Bloomington; IN 47405 USA
| | - James C. Lamb
- Center for Toxicology and Mechanistic Biology; Exponent Inc.; Alexandria VA 22314 USA
| | - James E. Klaunig
- Department of Environmental Health; Indiana University Bloomington; IN 47405 USA
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37
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Boess F, Lenz B, Funk J, Niederhauser U, Bassett S, Zhang JD, Singer T, Roth AB. Use of early phenotypic in vivo markers to assess human relevance of an unusual rodent non-genotoxic carcinogen in vitro. Toxicology 2017; 379:48-61. [PMID: 28174063 DOI: 10.1016/j.tox.2017.01.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 01/24/2017] [Accepted: 01/27/2017] [Indexed: 10/20/2022]
Abstract
Foci of altered hepatocytes (FAH) are considered putative, pre-neoplastic lesions that can occur spontaneously in aging rodents, but can also be induced by chemicals or drugs. Progression of FAH to hepatocellular neoplasms has been reported repeatedly but increases in foci in rodents do not necessarily lead to tumors in carcinogenicity studies and the relevance for humans often remains unclear. Here we present the case of RG3487, a molecule which induced FAH and, later on, tumors in rats. Because the molecule was negative in genotoxicity assays it was classified as a non-genotoxic carcinogen. In order to assess the potential for liver tumor formation in humans, we analyzed treatment-induced changes in vivo to establish a possible mode of action (MoA). In vivo and in vitro gene expression analysis revealed that nuclear receptor signaling was unlikely to be the relevant MoA and no other known mechanism could be established. We therefore took an approach comparing phenotypic markers, including mRNA changes, proliferation and glycogen accumulation, in vitro using cells of different species to assess the human relevance of this finding. Since the alterations observed in rats were not seen in the liver of mice or dogs in vivo, we could validate the relevance of the cell models chosen by use of hepatocytes from these species in vitro. This ultimately allowed for a cross-species comparison, which suggested that the formation of FAH and liver tumors was rat specific and unlikely to translate to human. Our work showed that phenotypic species comparison in vitro is a useful approach for assessment of the human relevance of pre-clinical findings where no known mechanism can be established.
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Affiliation(s)
- Franziska Boess
- Roche Pharmaceutical Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland.
| | - Barbara Lenz
- Roche Pharmaceutical Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland.
| | - Juergen Funk
- Roche Pharmaceutical Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland.
| | - Urs Niederhauser
- Roche Pharmaceutical Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland.
| | - Simon Bassett
- Roche Pharmaceutical Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland.
| | - Jitao David Zhang
- Roche Pharmaceutical Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland.
| | - Thomas Singer
- Roche Pharmaceutical Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland.
| | - Adrian B Roth
- Roche Pharmaceutical Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland.
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38
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One TEF concept does not fit all: The case for human risk assessment of polychlorinated biphenyls. CURRENT OPINION IN TOXICOLOGY 2017. [DOI: 10.1016/j.cotox.2017.01.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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39
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Xue Z, Li D, Yu W, Zhang Q, Hou X, He Y, Kou X. Mechanisms and therapeutic prospects of polyphenols as modulators of the aryl hydrocarbon receptor. Food Funct 2017; 8:1414-1437. [DOI: 10.1039/c6fo01810f] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Polyphenolic AhR modulators displayed concentration-, XRE-, gene-, species- and cell-specific agonistic/antagonistic activity.
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Affiliation(s)
- Zhaohui Xue
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
| | - Dan Li
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
| | - Wancong Yu
- Medical Plant Laboratory
- Tianjin Research Center of Agricultural Biotechnology
- Tianjin 3000381
- China
| | - Qian Zhang
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
| | - Xiaonan Hou
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
| | - Yulong He
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
| | - Xiaohong Kou
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
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40
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Wu JC, Lai CS, Tsai ML, Ho CT, Wang YJ, Pan MH. Chemopreventive effect of natural dietary compounds on xenobiotic-induced toxicity. J Food Drug Anal 2016; 25:176-186. [PMID: 28911535 PMCID: PMC9333419 DOI: 10.1016/j.jfda.2016.10.019] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Revised: 10/20/2016] [Accepted: 10/21/2016] [Indexed: 02/08/2023] Open
Abstract
Contaminants (or pollutants) that affect human health have become an important issue, spawning a myriad of studies on how to prevent harmful contaminant-induced effects. Recently, a variety of biological functions of natural dietary compounds derived from consumed foods and plants have been demonstrated in a number of studies. Natural dietary compounds exhibited several beneficial effects for the prevention of disease and the inhibition of chemically-induced carcinogenesis. Contaminant-induced toxicity and carcinogenesis are mostly attributed to the mutagenic activity of reactive metabolites and the disruption of normal biological functions. Therefore, the metabolic regulation of hazardous chemicals is key to reducing contaminant-induced adverse health effects. Moreover, promoting contaminant excretion from the body through Phase I and II metabolizing enzymes is also a useful strategy for reducing contaminant-induced toxicity. This review focuses on summarizing the natural dietary compounds derived from common dietary foods and plants and their possible mechanisms of action in the prevention/suppression of contaminant-induced toxicity.
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Affiliation(s)
- Jia-Ching Wu
- Department of Environmental and Occupational Health, National Cheng Kung University Medical College, Tainan, Taiwan
| | - Ching-Shu Lai
- Department of Seafood Science, National Kaohsiung Marine University, Kaohsiung, Taiwan
| | - Mei-Ling Tsai
- Department of Seafood Science, National Kaohsiung Marine University, Kaohsiung, Taiwan
| | - Chi-Tang Ho
- Department of Food Science, Rutgers University, New Brunswick, NJ, USA
| | - Ying-Jan Wang
- Department of Environmental and Occupational Health, National Cheng Kung University Medical College, Tainan, Taiwan; Department of Biomedical Informatics, Asia University, Taichung, Taiwan; Graduate Institute of Clinical Medicine, Taipei Medical University, Taipei, Taiwan.
| | - Min-Hsiung Pan
- Graduate Institute of Clinical Medicine, Taipei Medical University, Taipei, Taiwan; Department of Health and Nutrition Biotechnology, Asia University, Taichung, Taiwan; Institute of Food Science and Technology, National Taiwan University, Taipei, Taiwan.
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Phadnis-Moghe AS, Chen W, Li J, Crawford RB, Bach A, D'Ingillo S, Kovalova N, Suarez-Martinez JE, Kaplan BLF, Harrill JA, Budinsky R, Rowlands JC, Thomas RS, Kaminski NE. Immunological characterization of the aryl hydrocarbon receptor (AHR) knockout rat in the presence and absence of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Toxicology 2016; 368-369:172-182. [PMID: 27590929 DOI: 10.1016/j.tox.2016.08.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 08/01/2016] [Accepted: 08/30/2016] [Indexed: 12/15/2022]
Abstract
The aryl hydrocarbon receptor (AHR) has been extensively characterized for the essential role it plays in mediating the toxic responses elicited by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Despite similarities across animal species, species-specific differences exist in the profile of toxicity and sensitivity to TCDD owing, in part, to differences in the AHR. Newer reports have implicated the importance of AHR in the development and regulation of the immune system. Our present studies seek to further explore the essential role of AHR in lymphoid tissue composition, B cell function and the immunological responses after TCDD administration using the recently established AHR KO rats. Comprehensive immune cell phenotyping showed a decrease in the CD8+ T cell, CD11c+ populations and an increase in NKT cells in 3-week-old AHR KO rats compared to the WT controls. The lipopolysaccharide-induced IgM response and proliferation was markedly suppressed in the WT but not in the AHR KO B cells in the presence of TCDD. However, the percentage of LPS-activated IgM+ B cells was significantly higher in the AHR KO B cells as compared to that of WT suggesting the role of AHR in regulating the IgM response. The use of an AHR antagonist further alluded to the endogenous role of AHR in regulating B cell responses in the rat. Overall, the studies report for the first time, comprehensive immune cell phenotyping of the AHR KO rat and the endogenous role of AHR in the regulation of B cell function in the rat.
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Affiliation(s)
- Ashwini S Phadnis-Moghe
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, United States
| | - Weimin Chen
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, United States
| | - Jinpeng Li
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, United States; Genetics Program, Michigan State University, East Lansing, MI, 48824, United States
| | - Robert B Crawford
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, United States; Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, 48824, United States
| | - Anthony Bach
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, United States
| | - Shawna D'Ingillo
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, 48824, United States
| | - Natalia Kovalova
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, United States; Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, 48824, United States
| | - Jose E Suarez-Martinez
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, United States
| | - Barbara L F Kaplan
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, United States; Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, 48824, United States
| | - Joshua A Harrill
- The Hamner Institutes for Health Sciences, 6 Davis Drive, P.O. Box 12137, Research Triangle Park, NC, 27709, United States
| | | | | | - Russell S Thomas
- The Hamner Institutes for Health Sciences, 6 Davis Drive, P.O. Box 12137, Research Triangle Park, NC, 27709, United States
| | - Norbert E Kaminski
- Institute for Integrative Toxicology, Michigan State University, East Lansing, MI, 48824, United States; Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, 48824, United States.
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Xie HQ, Xu T, Chen Y, Li Y, Xia Y, Xu SL, Wang L, Tsim KWK, Zhao B. New perspectives for multi-level regulations of neuronal acetylcholinesterase by dioxins. Chem Biol Interact 2016; 259:286-290. [PMID: 27374124 DOI: 10.1016/j.cbi.2016.06.030] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 04/22/2016] [Accepted: 06/29/2016] [Indexed: 02/04/2023]
Abstract
Acetylcholinesterase (AChE; EC 3.1.1.7) is a vital functional enzyme in cholinergic neurotransmission which can rapidly hydrolyze neurotransmitter, acetylcholine, in the central and peripheral nervous systems. Emerging evidence showed that in addition to classical environmental AChE inhibitors, e.g. organophosphate and carbamate pesticides, dioxins are a new type of xenobiotic causing impairment of AChE. Dioxin can transcriptionally or post-transcriptionally suppress AChE expression in human neuroblastoma cells or mouse immune cells via the aryl hydrocarbon receptor (AhR) pathway, respectively. Dioxins can affect gene expression through other mechanisms, such as cross-talk with other signaling cascades and epigenetic modulations. Therefore, in this review, by summarizing the known mechanisms of AChE regulation and dioxin-induced gene alteration, potential signaling cascades and epigenetic mechanisms are proposed for dioxin-mediated AChE regulation. Mitogen activated protein (MAP) kinase, 3', 5'-cyclic adenosine monophosphate (cAMP) and calcium-related singaling pathways, as well as potential epigenetic mechanisms, such as DNA methylation, and post-transcriptional regulation via microRNAs, including hsa-miR-132, hsa-miR-212 and hsa-miR-25-3p are discussed here. These proposed mechanisms may be invaluable not only to promote comprehensive understanding of the action mechanisms for dioxin, but to illustrate the molecular basis of dioxin-induced health impacts.
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Affiliation(s)
- Heidi Q Xie
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Tuan Xu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Yangsheng Chen
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Yunping Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Yingjie Xia
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Sherry L Xu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Lingyun Wang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Karl W K Tsim
- Division of Life Science, Center for Chinese Medicine and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong, China
| | - Bin Zhao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China.
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Environmental Ligands of the Aryl Hydrocarbon Receptor and Their Effects in Models of Adult Liver Progenitor Cells. Stem Cells Int 2016; 2016:4326194. [PMID: 27274734 PMCID: PMC4870370 DOI: 10.1155/2016/4326194] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 04/07/2016] [Indexed: 12/20/2022] Open
Abstract
The toxicity of environmental and dietary ligands of the aryl hydrocarbon receptor (AhR) in mature liver parenchymal cells is well appreciated, while considerably less attention has been paid to their impact on cell populations exhibiting phenotypic features of liver progenitor cells. Here, we discuss the results suggesting that the consequences of the AhR activation in the cellular models derived from bipotent liver progenitors could markedly differ from those in hepatocytes. In contact-inhibited liver progenitor cells, the AhR agonists induce a range of effects potentially linked with tumor promotion. They can stimulate cell cycle progression/proliferation and deregulate cell-to-cell communication, which is associated with downregulation of proteins forming gap junctions, adherens junctions, and desmosomes (such as connexin 43, E-cadherin, β-catenin, and plakoglobin), as well as with reduced cell adhesion and inhibition of intercellular communication. At the same time, toxic AhR ligands may affect the activity of the signaling pathways contributing to regulation of liver progenitor cell activation and/or differentiation, such as downregulation of Wnt/β-catenin and TGF-β signaling, or upregulation of transcriptional targets of YAP/TAZ, the effectors of Hippo signaling pathway. These data illustrate the need to better understand the potential role of liver progenitors in the AhR-mediated liver carcinogenesis and tumor promotion.
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Gonzalez GH, Tahsin T, Goodale BC, Greene AC, Greene CS. Recent Advances and Emerging Applications in Text and Data Mining for Biomedical Discovery. Brief Bioinform 2015; 17:33-42. [PMID: 26420781 PMCID: PMC4719073 DOI: 10.1093/bib/bbv087] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Indexed: 02/06/2023] Open
Abstract
Precision medicine will revolutionize the way we treat and prevent disease. A major barrier to the implementation of precision medicine that clinicians and translational scientists face is understanding the underlying mechanisms of disease. We are starting to address this challenge through automatic approaches for information extraction, representation and analysis. Recent advances in text and data mining have been applied to a broad spectrum of key biomedical questions in genomics, pharmacogenomics and other fields. We present an overview of the fundamental methods for text and data mining, as well as recent advances and emerging applications toward precision medicine.
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Jackson DP, Joshi AD, Elferink CJ. Ah Receptor Pathway Intricacies; Signaling Through Diverse Protein Partners and DNA-Motifs. Toxicol Res (Camb) 2015; 4:1143-1158. [PMID: 26783425 PMCID: PMC4714567 DOI: 10.1039/c4tx00236a] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The Ah receptor is a transcription factor that modulates gene expression via interactions with multiple protein partners; these are reviewed, including the novel NC-XRE pathway involving KLF6.
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Harrill JA, Layko D, Nyska A, Hukkanen RR, Manno RA, Grassetti A, Lawson M, Martin G, Budinsky RA, Rowlands JC, Thomas RS. Aryl hydrocarbon receptor knockout rats are insensitive to the pathological effects of repeated oral exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin. J Appl Toxicol 2015; 36:802-14. [PMID: 26278112 DOI: 10.1002/jat.3211] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 05/24/2015] [Accepted: 06/14/2015] [Indexed: 12/31/2022]
Abstract
Sustained activation of the aryl hydrocarbon receptor (AHR) is believed to be the initial key event in AHR receptor-mediated tumorigenesis in the rat liver. The role of AHR in mediating pathological changes in the liver prior to tumor formation was investigated in a 4-week, repeated-dose study using adult female wild-type (WT) and AHR knockout (AHR-KO) rats treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Beginning at 8 weeks of age, AHR-KO and WT rats were dosed by oral gavage with varying concentrations of TCDD (0, 3, 22, 100, 300 and 1000 ng kg(-1) day(-1) ). Lung, liver and thymus histopathology, hematology, serum chemistry and the distribution of TCDD in liver and adipose tissue were examined. Treatment-related increases in the severity of liver and thymus pathology were observed in WT, but not AHR-KO rats. In the liver, these included hepatocellular hypertrophy, bile duct hyperplasia, multinucleated hepatocytes and inflammatory cell foci. A loss of cellularity in the thymic cortex and thymic atrophy was observed. Treatment-related changes in serum chemistry parameters were also observed in WT, but not AHR-KO rats. Finally, dose-dependent accumulation of TCDD was observed primarily in the liver of WT rats and primarily in the adipose tissue of AHR-KO rats. The results suggest that AHR activation is the initial key event underlying the progression of histological effects leading to liver tumorigenesis following TCDD treatment. Copyright © 2015 John Wiley & Sons, Ltd.
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Affiliation(s)
- Joshua A Harrill
- The Hamner Institutes for Health Sciences, Institute for Chemical Safety Sciences, Research Triangle Park, NC, 27709, USA
| | - Debra Layko
- The Hamner Institutes for Health Sciences, Institute for Chemical Safety Sciences, Research Triangle Park, NC, 27709, USA
| | - Abraham Nyska
- Consultant in Toxicologic Pathology, Sackler School of Medicine, Tel Aviv University, Timrat, 36576, Israel
| | | | | | | | - Marie Lawson
- The Dow Chemical Company, Midland, MI, 48640, USA
| | - Greg Martin
- The Dow Chemical Company, Midland, MI, 48640, USA
| | | | | | - Russell S Thomas
- The Hamner Institutes for Health Sciences, Institute for Chemical Safety Sciences, Research Triangle Park, NC, 27709, USA
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47
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Wang Z, Neal BH, Lamb JC, Klaunig JE. Mechanistic Investigation of Toxaphene Induced Mouse Liver Tumors. Toxicol Sci 2015; 147:549-61. [DOI: 10.1093/toxsci/kfv151] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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48
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Becker RA, Patlewicz G, Simon TW, Rowlands JC, Budinsky RA. The adverse outcome pathway for rodent liver tumor promotion by sustained activation of the aryl hydrocarbon receptor. Regul Toxicol Pharmacol 2015; 73:172-90. [PMID: 26145830 DOI: 10.1016/j.yrtph.2015.06.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 06/19/2015] [Accepted: 06/22/2015] [Indexed: 12/29/2022]
Abstract
An Adverse Outcome Pathway (AOP) represents the existing knowledge of a biological pathway leading from initial molecular interactions of a toxicant and progressing through a series of key events (KEs), culminating with an apical adverse outcome (AO) that has to be of regulatory relevance. An AOP based on the mode of action (MOA) of rodent liver tumor promotion by dioxin-like compounds (DLCs) has been developed and the weight of evidence (WoE) of key event relationships (KERs) evaluated using evolved Bradford Hill considerations. Dioxins and DLCs are potent aryl hydrocarbon receptor (AHR) ligands that cause a range of species-specific adverse outcomes. The occurrence of KEs is necessary for inducing downstream biological responses and KEs may occur at the molecular, cellular, tissue and organ levels. The common convention is that an AOP begins with the toxicant interaction with a biological response element; for this AOP, this initial event is binding of a DLC ligand to the AHR. Data from mechanistic studies, lifetime bioassays and approximately thirty initiation-promotion studies have established dioxin and DLCs as rat liver tumor promoters. Such studies clearly show that sustained AHR activation, weeks or months in duration, is necessary to induce rodent liver tumor promotion--hence, sustained AHR activation is deemed the molecular initiating event (MIE). After this MIE, subsequent KEs are 1) changes in cellular growth homeostasis likely associated with expression changes in a number of genes and observed as development of hepatic foci and decreases in apoptosis within foci; 2) extensive liver toxicity observed as the constellation of effects called toxic hepatopathy; 3) cellular proliferation and hyperplasia in several hepatic cell types. This progression of KEs culminates in the AO, the development of hepatocellular adenomas and carcinomas and cholangiolar carcinomas. A rich data set provides both qualitative and quantitative knowledge of the progression of this AOP through KEs and the KERs. Thus, the WoE for this AOP is judged to be strong. Species-specific effects of dioxins and DLCs are well known--humans are less responsive than rodents and rodent species differ in sensitivity between strains. Consequently, application of this AOP to evaluate potential human health risks must take these differences into account.
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Affiliation(s)
- Richard A Becker
- Regulatory and Technical Affairs Department, American Chemistry Council (ACC), Washington, DC 20002, USA.
| | - Grace Patlewicz
- DuPont Haskell Global Centers for Health and Environmental Sciences, Newark, DE 19711, USA
| | - Ted W Simon
- Ted Simon LLC, 4184 Johnston Road, Winston, GA 30187, USA
| | - J Craig Rowlands
- The Dow Chemical Company, Toxicology & Environmental Research & Consulting, 1803 Building Washington Street, Midland, MI 48674, USA
| | - Robert A Budinsky
- The Dow Chemical Company, Toxicology & Environmental Research & Consulting, 1803 Building Washington Street, Midland, MI 48674, USA
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49
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Simon TW, Budinsky RA, Rowlands JC. A model for aryl hydrocarbon receptor-activated gene expression shows potency and efficacy changes and predicts squelching due to competition for transcription co-activators. PLoS One 2015; 10:e0127952. [PMID: 26039703 PMCID: PMC4454675 DOI: 10.1371/journal.pone.0127952] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 04/22/2015] [Indexed: 12/17/2022] Open
Abstract
A stochastic model of nuclear receptor-mediated transcription was developed based on activation of the aryl hydrocarbon receptor (AHR) by 2,3,7,8-tetrachlorodibenzodioxin (TCDD) and subsequent binding the activated AHR to xenobiotic response elements (XREs) on DNA. The model was based on effects observed in cells lines commonly used as in vitro experimental systems. Following ligand binding, the AHR moves into the cell nucleus and forms a heterodimer with the aryl hydrocarbon nuclear translocator (ARNT). In the model, a requirement for binding to DNA is that a generic coregulatory protein is subsequently bound to the AHR-ARNT dimer. Varying the amount of coregulator available within the nucleus altered both the potency and efficacy of TCDD for inducing for transcription of CYP1A1 mRNA, a commonly used marker for activation of the AHR. Lowering the amount of available cofactor slightly increased the EC50 for the transcriptional response without changing the efficacy or maximal response. Further reduction in the amount of cofactor reduced the efficacy and produced non-monotonic dose-response curves (NMDRCs) at higher ligand concentrations. The shapes of these NMDRCs were reminiscent of the phenomenon of squelching. Resource limitations for transcriptional machinery are becoming apparent in eukaryotic cells. Within single cells, nuclear receptor-mediated gene expression appears to be a stochastic process; however, intercellular communication and other aspects of tissue coordination may represent a compensatory process to maintain an organism’s ability to respond on a phenotypic level to various stimuli within an inconstant environment.
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Affiliation(s)
- Ted W. Simon
- Ted Simon LLC, Winston, GA, United States of America
- * E-mail:
| | - Robert A. Budinsky
- The Dow Chemical Company, Toxicology and Environmental Research & Consulting. Midland, MI, United States of America
| | - J. Craig Rowlands
- The Dow Chemical Company, Toxicology and Environmental Research & Consulting. Midland, MI, United States of America
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50
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Hu Z, Brooks SA, Dormoy V, Hsu CW, Hsu HY, Lin LT, Massfelder T, Rathmell WK, Xia M, Al-Mulla F, Al-Temaimi R, Amedei A, Brown DG, Prudhomme KR, Colacci A, Hamid RA, Mondello C, Raju J, Ryan EP, Woodrick J, Scovassi AI, Singh N, Vaccari M, Roy R, Forte S, Memeo L, Salem HK, Lowe L, Jensen L, Bisson WH, Kleinstreuer N. Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: focus on the cancer hallmark of tumor angiogenesis. Carcinogenesis 2015; 36 Suppl 1:S184-202. [PMID: 26106137 PMCID: PMC4492067 DOI: 10.1093/carcin/bgv036] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 12/12/2014] [Accepted: 12/15/2014] [Indexed: 01/09/2023] Open
Abstract
One of the important 'hallmarks' of cancer is angiogenesis, which is the process of formation of new blood vessels that are necessary for tumor expansion, invasion and metastasis. Under normal physiological conditions, angiogenesis is well balanced and controlled by endogenous proangiogenic factors and antiangiogenic factors. However, factors produced by cancer cells, cancer stem cells and other cell types in the tumor stroma can disrupt the balance so that the tumor microenvironment favors tumor angiogenesis. These factors include vascular endothelial growth factor, endothelial tissue factor and other membrane bound receptors that mediate multiple intracellular signaling pathways that contribute to tumor angiogenesis. Though environmental exposures to certain chemicals have been found to initiate and promote tumor development, the role of these exposures (particularly to low doses of multiple substances), is largely unknown in relation to tumor angiogenesis. This review summarizes the evidence of the role of environmental chemical bioactivity and exposure in tumor angiogenesis and carcinogenesis. We identify a number of ubiquitous (prototypical) chemicals with disruptive potential that may warrant further investigation given their selectivity for high-throughput screening assay targets associated with proangiogenic pathways. We also consider the cross-hallmark relationships of a number of important angiogenic pathway targets with other cancer hallmarks and we make recommendations for future research. Understanding of the role of low-dose exposure of chemicals with disruptive potential could help us refine our approach to cancer risk assessment, and may ultimately aid in preventing cancer by reducing or eliminating exposures to synergistic mixtures of chemicals with carcinogenic potential.
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Affiliation(s)
- Zhiwei Hu
- To whom correspondence should be addressed. Tel: +1 614 685 4606; Fax: +1-614-247-7205;
| | - Samira A. Brooks
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Valérian Dormoy
- INSERM U1113, team 3 “Cell Signalling and Communication in Kidney and Prostate Cancer”, University of Strasbourg, Facultée de Médecine, 67085 Strasbourg, France
- Department of Cell and Developmental Biology, University of California, Irvine, CA 92697, USA
| | - Chia-Wen Hsu
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20892-3375, USA
| | - Hsue-Yin Hsu
- Department of Life Sciences, Tzu-Chi University, Taiwan, Republic of China
| | - Liang-Tzung Lin
- Department of Microbiology and Immunology, Taipei Medical University, Taiwan, Republic of China
| | - Thierry Massfelder
- INSERM U1113, team 3 “Cell Signalling and Communication in Kidney and Prostate Cancer”, University of Strasbourg, Facultée de Médecine, 67085 Strasbourg, France
| | - W. Kimryn Rathmell
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Menghang Xia
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20892-3375, USA
| | - Fahd Al-Mulla
- Department of Life Sciences, Tzu-Chi University, Taiwan, Republic of China
| | | | - Amedeo Amedei
- Department of Experimental and Clinical Medicine, University of Firenze, Florence 50134, Italy
| | - Dustin G. Brown
- Department of Environmental and Radiological Health Sciences
, Colorado State University/Colorado School of Public Health, Fort Collins, CO 80523, USA
| | - Kalan R. Prudhomme
- Environmental and Molecular Toxicology, Environmental Health Science Center, Oregon State University, Corvallis, OR 97331, USA
| | - Annamaria Colacci
- Center for Environmental Carcinogenesis and Risk Assessment, Environmental Protection and Health Prevention Agency, Bologna, Italy
| | - Roslida A. Hamid
- Faculty of Medicine and Health Sciences, University Putra, Serdang, Selangor, Malaysia
| | - Chiara Mondello
- Institute of Molecular Genetics, National Research Council, Pavia 27100, Italy
| | - Jayadev Raju
- Regulatory Toxicology Research Division, Bureau of Chemical Safety, Food Directorate
, Health Products and Food Branch Health Canada, Ottawa, Ontario K1A0K9, Canada
| | - Elizabeth P. Ryan
- Department of Environmental and Radiological Health Sciences
, Colorado State University/Colorado School of Public Health, Fort Collins, CO 80523, USA
| | - Jordan Woodrick
- Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, WashingtonDC 20057, USA
| | - A. Ivana Scovassi
- Institute of Molecular Genetics, National Research Council, Pavia 27100, Italy
| | - Neetu Singh
- Advanced Molecular Science Research Centre (Centre for Advance Research), King George’s Medical University, Lucknow, Uttar Pradesh 226003, India
| | - Monica Vaccari
- Center for Environmental Carcinogenesis and Risk Assessment, Environmental Protection and Health Prevention Agency, Bologna, Italy
| | - Rabindra Roy
- Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, WashingtonDC 20057, USA
| | - Stefano Forte
- Mediterranean Institute of Oncology, Viagrande 95029, Italy
| | - Lorenzo Memeo
- Mediterranean Institute of Oncology, Viagrande 95029, Italy
| | - Hosni K. Salem
- Urology Department, kasr Al-Ainy School of Medicine, Cairo University, El Manial, Cairo 12515, Egypt
| | - Leroy Lowe
- Getting to Know Cancer, Truro, Nova Scotia B2N 1X5, Canada
| | - Lasse Jensen
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden and
| | - William H. Bisson
- Environmental and Molecular Toxicology, Environmental Health Science Center, Oregon State University, Corvallis, OR 97331, USA
| | - Nicole Kleinstreuer
- Integrated Laboratory Systems, Inc., in support of the National Toxicology Program Interagency Center for the Evaluation of Alternative Toxicological Methods, NIEHS, MD K2-16, RTP, NC 27709, USA
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