1
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Corton JC, Ledbetter V, Cohen SM, Atlas E, Yauk CL, Liu J. A transcriptomic biomarker predictive of cell proliferation for use in adverse outcome pathway-informed testing and assessment. Toxicol Sci 2024; 201:174-189. [PMID: 39137154 DOI: 10.1093/toxsci/kfae102] [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] [Indexed: 08/15/2024] Open
Abstract
High-throughput transcriptomics (HTTr) is increasingly being used to identify molecular targets of chemicals that can be linked to adverse outcomes. Cell proliferation (CP) is an important key event in chemical carcinogenesis. Here, we describe the construction and characterization of a gene expression biomarker that is predictive of the CP status in human and rodent tissues. The biomarker was constructed from 30 genes known to be increased in expression in prostate cancers relative to surrounding tissues and in cycling human MCF-7 cells after estrogen receptor (ER) agonist exposure. Using a large compendium of gene expression profiles to test utility, the biomarker could identify increases in CP in (i) 308 out of 367 tumor vs. normal surrounding tissue comparisons from 6 human organs, (ii) MCF-7 cells after activation of ER, (iii) after partial hepatectomy in mice and rats, and (iv) the livers of mice and rats after exposure to nongenotoxic hepatocarcinogens. The biomarker identified suppression of CP (i) under conditions of p53 activation by DNA damaging agents in human cells, (ii) in human A549 lung cells exposed to therapeutic anticancer kinase inhibitors (dasatinib, nilotnib), and (iii) in the mouse liver when comparing high levels of CP at birth to the low background levels in the adult. The responses using the biomarker were similar to those observed using conventional markers of CP including PCNA, Ki67, and BrdU labeling. The CP biomarker will be a useful tool for interpretation of HTTr data streams to identify CP status after exposure to chemicals in human cells or in rodent tissues.
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Affiliation(s)
- J Christopher Corton
- Center for Computational Toxicology and Exposure, US Environmental Protection Agency, Research Triangle Park, NC 27711, United States
| | - Victoria Ledbetter
- Center for Computational Toxicology and Exposure, US Environmental Protection Agency, Research Triangle Park, NC 27711, United States
| | - Samuel M Cohen
- Department of Pathology and Microbiology and Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 69198-3135, United States
| | - Ella Atlas
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch (HECSB) Health Canada, Ottawa, ON K2K 0K9, Canada
| | - Carole L Yauk
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Jie Liu
- Center for Computational Toxicology and Exposure, US Environmental Protection Agency, Research Triangle Park, NC 27711, United States
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2
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Gutmann M, Stimpfl E, Langmann G, Koudelka H, Mir-Karner B, Grasl-Kraupp B. Differentiated and non-differentiated HepaRG™ cells: A possible in-vitro model system for early hepatocarcinogenesis and non-genotoxic carcinogens. Toxicol Lett 2023; 390:15-24. [PMID: 37890683 DOI: 10.1016/j.toxlet.2023.10.014] [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: 06/21/2023] [Revised: 10/17/2023] [Accepted: 10/24/2023] [Indexed: 10/29/2023]
Abstract
Many xenobiotics are non-genotoxic carcinogens (NGC) in rodent liver. Their mode of action (MoA) and health risks for humans are unclear and no in-vitro tests are available to predict NGC. Human HepaRG™ cells in the differentiated (d-HepaRG) and non-differentiated state (nd-HepaRG) were studied as new approach methodology (NAM) for NGC. Cell-biological assays were performed with d-/nd-HepaRG and human hepatoma/hepatocarcinoma cell lines to characterize the benign/malignant phenotype. Reaction of d-/nd-HepaRG to several liver growth factors and NGC (phenobarbital, PB; cyproterone acetate, CPA; WY-14643) was compared to unaltered and premalignant rat hepatocytes in ex-vivo culture. Enzyme induction by NGC was checked by RT-qPCR/oligo-arrays. Growth, anchorage-independency, migration, clonogenicity, and in-vivo tumorigenicity of nd-HepaRG ranged between benign d-HepaRG and malignant hepatoma/hepatocarcinoma cells. All growth factors elevated DNA replication of d-/nd-HepaRG cells, similarly to unaltered/premalignant rat hepatocytes. NGC induced their prototypical enzymes in the rat and human cells, but elicited a growth response only in the unaltered/premalignant rat hepatocytes and not in human d-/nd-HepaRG cells. To conclude, a benign/premalignant phenotype of d-/nd-HepaRG cells and a reactivity towards several hepatic growth factors and NGC, as known from human hepatocytes, are essential components for an in-vitro model for early stage human hepatocarcinogenesis.The potential value as new approach methodology (NAM) for NGC is discussed.
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Affiliation(s)
- Michael Gutmann
- Center for Cancer Research, Medical University of Vienna, Borschkegasse 8a, 1090 Vienna, Austria
| | - Emily Stimpfl
- Center for Cancer Research, Medical University of Vienna, Borschkegasse 8a, 1090 Vienna, Austria
| | - Gregor Langmann
- Center for Cancer Research, Medical University of Vienna, Borschkegasse 8a, 1090 Vienna, Austria
| | - Helga Koudelka
- Center for Cancer Research, Medical University of Vienna, Borschkegasse 8a, 1090 Vienna, Austria
| | - Birgit Mir-Karner
- Center for Cancer Research, Medical University of Vienna, Borschkegasse 8a, 1090 Vienna, Austria
| | - Bettina Grasl-Kraupp
- Center for Cancer Research, Medical University of Vienna, Borschkegasse 8a, 1090 Vienna, Austria.
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3
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Nelson GM, Carswell GK, Swartz CD, Recio L, Yauk CL, Chorley BN. Early microRNA responses in rodent liver mediated by furan exposure establish dose thresholds for later adverse outcomes. Toxicol Lett 2023; 384:105-114. [PMID: 37517673 PMCID: PMC10530563 DOI: 10.1016/j.toxlet.2023.07.015] [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] [Received: 07/10/2023] [Accepted: 07/27/2023] [Indexed: 08/01/2023]
Abstract
To reduce reliance on long-term in vivo studies, short-term data linking early molecular-based measurements to later adverse health effects is needed. Although transcriptional-based benchmark dose (BMDT) modeling has been used to estimate potencies and stratify chemicals based on potential to induce later-life effects, dose-responsive epigenetic alterations have not been routinely considered. Here, we evaluated the utility of microRNA (miRNA) profiling in mouse liver and blood, as well as in mouse primary hepatocytes in vitro, to indicate mechanisms of liver perturbation due to short-term exposure of the known rodent liver hepatotoxicant and carcinogen, furan. Benchmark dose modeling of miRNA measurements (BMDmiR) were compared to the referent transcriptional (BMDT) and apical (BMDA) estimates. These analyses indicate a robust dose response for 34 miRNAs to furan and involvement of p53-linked pathways in furan-mediated hepatotoxicity, supporting mRNA and apical measurements. Liver-sourced miRNAs were also altered in the blood and primary hepatocytes. Overall, these results indicate mechanistic involvement of miRNA in furan carcinogenicity and provide evidence of their potential utility as accessible biomarkers of exposure and disease.
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Affiliation(s)
- Gail M Nelson
- US Environmental Protection Agency, Research Triangle Park, NC 27709, USA
| | - Gleta K Carswell
- US Environmental Protection Agency, Research Triangle Park, NC 27709, USA
| | - Carol D Swartz
- Inotiv Co., 601 Keystone Park Drive, Suite 200, Morrisville, NC 27560, USA
| | - Leslie Recio
- ScitoVation, 100 Capitola Drive Suite 106, Durham, NC 27713, USA
| | - Carole L Yauk
- Dept. Of Biology, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Brian N Chorley
- US Environmental Protection Agency, Research Triangle Park, NC 27709, USA.
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4
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Yoshinari K, Shizu R. Distinct roles of the sister nuclear receptors PXR and CAR in liver cancer development. Drug Metab Dispos 2022; 50:1019-1026. [DOI: 10.1124/dmd.121.000481] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 02/08/2022] [Indexed: 11/22/2022] Open
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5
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Skoda J, Dohnalova K, Chalupsky K, Stahl A, Templin M, Maixnerova J, Micuda S, Grøntved L, Braeuning A, Pavek P. Off-target lipid metabolism disruption by the mouse constitutive androstane receptor ligand TCPOBOP in humanized mice. Biochem Pharmacol 2021; 197:114905. [PMID: 34971590 DOI: 10.1016/j.bcp.2021.114905] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 12/21/2021] [Accepted: 12/22/2021] [Indexed: 12/14/2022]
Abstract
The constitutive androstane receptor (CAR) controls xenobiotic clearance, regulates liver glucose, lipid metabolism, and energy homeostasis. These functions have been mainly discovered using the prototypical mouse-specific CAR ligand TCPOBOP in wild-type or CAR null mice. However, TCPOBOP is reported to result in some off-target metabolic effects in CAR null mice. In this study, we compared the metabolic effects of TCPOBOP using lipidomic, transcriptomic, and proteomic analyses in wild-type and humanized CAR-PXR-CYP3A4/3A7 mice. In the model, human CAR retains its constitutive activity in metabolism regulation; however, it is not activated by TCPOBOB. Notably, we observed that TCPOBOP affected lipid homeostasis by elevating serum and liver triglyceride levels and promoted hepatocyte hypertrophy in humanized CAR mice. Hepatic lipidomic analysis revealed a significant accumulation of triglycerides and decrease of its metabolites in humanized CAR mice. RNA-seq analysis has shown divergent gene expression levels in wild-type and humanized CAR mice. Gene expression regulation in humanized mice is mainly involved in lipid metabolic processes and in the PPAR, leptin, thyroid, and circadian clock pathways. In contrast, CAR activation by TCPOBOP in wild-type mice reduced liver and plasma triglyceride levels and induced a typical transcriptomic proliferative response in the liver. In summary, we identified TCPOBOP as a disruptor of lipid metabolism in humanized CAR mice. The divergent effects of TCPOBOP in humanized mice in comparison with the prototypical CAR-mediated response in WT mice warrant the use of appropriate model ligands and humanized animal models during the testing of endocrine disruption and the characterization of adverse outcome pathways.
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Affiliation(s)
- Josef Skoda
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Charles University, Heyrovskeho 1203, 500 05 Hradec Kralove, Czech Republic
| | - Klara Dohnalova
- Czech Centre for Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague, Czech Republic; First Faculty of Medicine, Charles University, Katerinska 32, 121 08 Prague, Czech Republic
| | - Karel Chalupsky
- Czech Centre for Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague, Czech Republic
| | - Aaron Stahl
- NMI - Natural and Medical Sciences Institute at the University of Tuebingen, Markwiesenstr. 55, 72770 Reutlingen, Germany
| | - Markus Templin
- NMI - Natural and Medical Sciences Institute at the University of Tuebingen, Markwiesenstr. 55, 72770 Reutlingen, Germany
| | - Jana Maixnerova
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Charles University, Heyrovskeho 1203, 500 05 Hradec Kralove, Czech Republic
| | - Stanislav Micuda
- Department of Pharmacology, Medical Faculty in Hradec Kralove, Charles University, Simkova 870, 500 03 Hradec Kralove, Czech Republic
| | - Lars Grøntved
- Functional Genomics and Metabolism Research Unit, Department of Biochemistry and Molecular Biology, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, Odense M 5230, Denmark
| | - Albert Braeuning
- Department Food Safety, German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, Berlin 10589, Germany
| | - Petr Pavek
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Charles University, Heyrovskeho 1203, 500 05 Hradec Kralove, Czech Republic.
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6
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Li Z, Li L, Heyward S, Men S, Xu M, Sueyoshi T, Wang H. Phenobarbital Induces SLC13A5 Expression through Activation of PXR but Not CAR in Human Primary Hepatocytes. Cells 2021; 10:cells10123381. [PMID: 34943889 PMCID: PMC8699749 DOI: 10.3390/cells10123381] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 11/26/2021] [Accepted: 11/29/2021] [Indexed: 02/05/2023] Open
Abstract
Phenobarbital (PB), a widely used antiepileptic drug, is known to upregulate the expression of numerous drug-metabolizing enzymes and transporters in the liver primarily via activation of the constitutive androstane receptor (CAR, NR1I3). The solute carrier family 13 member 5 (SLC13A5), a sodium-coupled citrate transporter, plays an important role in intracellular citrate homeostasis that is associated with a number of metabolic syndromes and neurological disorders. Here, we show that PB markedly elevates the expression of SLC13A5 through a pregnane X receptor (PXR)-dependent but CAR-independent signaling pathway. In human primary hepatocytes, the mRNA and protein expression of SLC13A5 was robustly induced by PB treatment, while genetic knockdown or pharmacological inhibition of PXR significantly attenuated this induction. Utilizing genetically modified HepaRG cells, we found that PB induces SLC13A5 expression in both wild type and CAR-knockout HepaRG cells, whereas such induction was fully abolished in the PXR-knockout HepaRG cells. Mechanistically, we identified and functionally characterized three enhancer modules located upstream from the transcription start site or introns of the SLC13A5 gene that are associated with the regulation of PXR-mediated SLC13A5 induction. Moreover, metformin, a deactivator of PXR, dramatically suppressed PB-mediated induction of hepatic SLC13A5 as well as its activation of the SLC13A5 luciferase reporter activity via PXR. Collectively, these data reveal PB as a potent inducer of SLC13A5 through the activation of PXR but not CAR in human primary hepatocytes.
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Affiliation(s)
- Zhihui Li
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 Penn Street, Baltimore, MD 21201, USA; (Z.L.); (L.L.); (S.M.)
| | - Linhao Li
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 Penn Street, Baltimore, MD 21201, USA; (Z.L.); (L.L.); (S.M.)
| | - Scott Heyward
- BioIVT, 1450 S Rolling Road, Halethorpe, MD 21227, USA;
| | - Shuaiqian Men
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 Penn Street, Baltimore, MD 21201, USA; (Z.L.); (L.L.); (S.M.)
| | - Meishu Xu
- Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261, USA;
| | - Tatsuya Sueyoshi
- Pharmacogenetics Section, Laboratory of Reproductive and Developmental Toxicology, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA;
| | - Hongbing Wang
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 Penn Street, Baltimore, MD 21201, USA; (Z.L.); (L.L.); (S.M.)
- Correspondence: ; Tel.: +1-410-706-1280
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7
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Desaulniers D, Vasseur P, Jacobs A, Aguila MC, Ertych N, Jacobs MN. Integration of Epigenetic Mechanisms into Non-Genotoxic Carcinogenicity Hazard Assessment: Focus on DNA Methylation and Histone Modifications. Int J Mol Sci 2021; 22:10969. [PMID: 34681626 PMCID: PMC8535778 DOI: 10.3390/ijms222010969] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 09/30/2021] [Accepted: 10/04/2021] [Indexed: 12/15/2022] Open
Abstract
Epigenetics involves a series of mechanisms that entail histone and DNA covalent modifications and non-coding RNAs, and that collectively contribute to programing cell functions and differentiation. Epigenetic anomalies and DNA mutations are co-drivers of cellular dysfunctions, including carcinogenesis. Alterations of the epigenetic system occur in cancers whether the initial carcinogenic events are from genotoxic (GTxC) or non-genotoxic (NGTxC) carcinogens. NGTxC are not inherently DNA reactive, they do not have a unifying mode of action and as yet there are no regulatory test guidelines addressing mechanisms of NGTxC. To fil this gap, the Test Guideline Programme of the Organisation for Economic Cooperation and Development is developing a framework for an integrated approach for the testing and assessment (IATA) of NGTxC and is considering assays that address key events of cancer hallmarks. Here, with the intent of better understanding the applicability of epigenetic assays in chemical carcinogenicity assessment, we focus on DNA methylation and histone modifications and review: (1) epigenetic mechanisms contributing to carcinogenesis, (2) epigenetic mechanisms altered following exposure to arsenic, nickel, or phenobarbital in order to identify common carcinogen-specific mechanisms, (3) characteristics of a series of epigenetic assay types, and (4) epigenetic assay validation needs in the context of chemical hazard assessment. As a key component of numerous NGTxC mechanisms of action, epigenetic assays included in IATA assay combinations can contribute to improved chemical carcinogen identification for the better protection of public health.
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Affiliation(s)
- Daniel Desaulniers
- Environmental Health Sciences and Research Bureau, Hazard Identification Division, Health Canada, AL:2203B, Ottawa, ON K1A 0K9, Canada
| | - Paule Vasseur
- CNRS, LIEC, Université de Lorraine, 57070 Metz, France;
| | - Abigail Jacobs
- Independent at the Time of Publication, Previously US Food and Drug Administration, Rockville, MD 20852, USA;
| | - M. Cecilia Aguila
- Toxicology Team, Division of Human Food Safety, Center for Veterinary Medicine, US Food and Drug Administration, Department of Health and Human Services, Rockville, MD 20852, USA;
| | - Norman Ertych
- German Centre for the Protection of Laboratory Animals (Bf3R), German Federal Institute for Risk Assessment, Diedersdorfer Weg 1, 12277 Berlin, Germany;
| | - Miriam N. Jacobs
- Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton OX11 0RQ, UK;
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8
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Yamada T. Application of humanized mice to toxicology studies: Evaluation of the human relevance of the mode of action for rodent liver tumor formation by activators of the constitutive androstane receptor (CAR). J Toxicol Pathol 2021; 34:283-297. [PMID: 34629731 PMCID: PMC8484926 DOI: 10.1293/tox.2021-0027] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 06/08/2021] [Indexed: 12/31/2022] Open
Abstract
The constitutive androstane receptor (CAR)-mediated mode of action (MOA) for phenobarbital (PB)-induced rodent liver tumor formation has been established, with increased hepatocyte proliferation, which is a key event in tumor formation. Previous studies have demonstrated that PB and other CAR-activators stimulate proliferation in cultured rodent hepatocytes, but not in cultured human hepatocytes. However, in the genetically humanized CAR and pregnane X receptor (PXR) mouse (hCAR/hPXR mouse, downstream genes are still mouse), PB increased hepatocyte proliferation and tumor production in vivo. In contrast to the hCAR/hPXR mouse, studies with chimeric mice with human hepatocytes (PXB-mouse, both receptor and downstream genes are human) demonstrated that PB did not increase human hepatocyte proliferation in vivo. PB increased hepatocyte proliferation in a chimeric mouse model with rat hepatocytes, indicating that the lack of human hepatocyte proliferation is not due to any functional defect in the chimeric mouse liver environment. Gene expression analysis demonstrated that the downstream genes of CAR/PXR activation were similar in hCAR/hPXR and CD-1 mice, but differed from those observed in chimeric mice with human hepatocytes. These findings strongly support the conclusion that the MOA for CAR-mediated rodent liver tumor formation is qualitatively implausible for humans. Indeed, epidemiological studies have found no causal link between PB and human liver tumors. There are many similarities with respect to hepatic effects and species differences between rodent CAR and peroxisome proliferator-activated receptor α activators. Based on our research, the chimeric mouse with human hepatocytes (PXB-mouse) is reliable for human cancer risk assessment of test chemicals.
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Affiliation(s)
- Tomoya Yamada
- Environmental Health Science Laboratory, Sumitomo Chemical Co., Ltd., 3-1-98 Kasugade-naka, Konohana-ku, Osaka 554-8558, Japan
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9
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Lim JJ, Dutta M, Dempsey JL, Lehmler HJ, MacDonald J, Bammler T, Walker C, Kavanagh TJ, Gu H, Mani S, Cui JY. Neonatal Exposure to BPA, BDE-99, and PCB Produces Persistent Changes in Hepatic Transcriptome Associated With Gut Dysbiosis in Adult Mouse Livers. Toxicol Sci 2021; 184:83-103. [PMID: 34453844 PMCID: PMC8557404 DOI: 10.1093/toxsci/kfab104] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Recent evidence suggests that complex diseases can result from early life exposure to environmental toxicants. Polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs) are persistent organic pollutants (POPs) and remain a continuing risk to human health despite being banned from production. Developmental BPA exposure mediated-adult onset of liver cancer via epigenetic reprogramming mechanisms has been identified. Here, we investigated whether the gut microbiome and liver can be persistently reprogrammed following neonatal exposure to POPs, and the associations between microbial biomarkers and disease-prone changes in the hepatic transcriptome in adulthood, compared with BPA. C57BL/6 male and female mouse pups were orally administered vehicle, BPA, BDE-99 (a breast milk-enriched PBDE congener), or the Fox River PCB mixture (PCBs), once daily for three consecutive days (postnatal days [PND] 2-4). Tissues were collected at PND5 and PND60. Among the three chemicals investigated, early life exposure to BDE-99 produced the most prominent developmental reprogramming of the gut-liver axis, including hepatic inflammatory and cancer-prone signatures. In adulthood, neonatal BDE-99 exposure resulted in a persistent increase in Akkermansia muciniphila throughout the intestine, accompanied by increased hepatic levels of acetate and succinate, the known products of A. muciniphila. In males, this was positively associated with permissive epigenetic marks H3K4me1 and H3K27, which were enriched in loci near liver cancer-related genes that were dysregulated following neonatal exposure to BDE-99. Our findings provide novel insights that early life exposure to POPs can have a life-long impact on disease risk, which may partly be regulated by the gut microbiome.
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Affiliation(s)
- Joe Jongpyo Lim
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
| | - Moumita Dutta
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
| | - Joseph L Dempsey
- Division of Gastroenterology, Department of Medicine, School of Medicine, University of Washington, Seattle, Washington, USA,Center for Microbiome Sciences and Therapeutics, School of Medicine, University of Washington, Seattle, Washington, USA
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, University of Iowa, Iowa City, Iowa, USA
| | - James MacDonald
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
| | - Theo Bammler
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
| | - Cheryl Walker
- Center for Precision Environmental Health, Baylor College of Medicine, Houston, Texas 77030, USA,Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA,Department of Medicine, Baylor College of Medicine, Houston, Texas 77030, USA,Dan L. Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, Texas 77030, USA,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Terrance J Kavanagh
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
| | - Haiwei Gu
- Arizona Metabolomics Laboratory, College of Health Solutions, Arizona State University, Pheonix, Arizona 85004, USA
| | - Sridhar Mani
- Department of Medicine, Molecular Pharmacology and Genetics, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Julia Yue Cui
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA,To whom correspondence should be addressed at Department of Environmental and Occupational Health Sciences, University of Washington, 4225 Roosevelt Way NE, Seattle, WA 98105, USA. E-mail:
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10
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Yamada T, Ohara A, Ozawa N, Maeda K, Kondo M, Okuda Y, Abe J, Cohen SM, Lake BG. Comparison of the Hepatic Effects of Phenobarbital in Chimeric Mice Containing Either Rat or Human Hepatocytes With Humanized Constitutive Androstane Receptor and Pregnane X Receptor Mice. Toxicol Sci 2021; 177:362-376. [PMID: 32735318 DOI: 10.1093/toxsci/kfaa125] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Using a chimeric mouse humanized liver model, we provided evidence that human hepatocytes are refractory to the mitogenic effects of rodent constitutive androstane receptor (CAR) activators. To evaluate the functional reliability of this model, the present study examined mitogenic responses to phenobarbital (PB) in chimeric mice transplanted with rat hepatocytes, because rats are responsive to CAR activators. Treatment with 1000 ppm PB for 7 days significantly increased replicative DNA synthesis (RDS) in rat hepatocytes of the chimeric mice, demonstrating that the transplanted hepatocyte model is functionally reliable for cell proliferation analysis. Treatment of humanized CAR and pregnane X receptor (PXR) mice (hCAR/hPXR mice) with 1000 ppm PB for 7 days significantly increased hepatocyte RDS together with increases in several mitogenic genes. Global gene expression analysis was performed with liver samples from this and from previous studies focusing on PB-induced Wnt/β-catenin signaling and showed that altered genes in hCAR/hPXR mice clustered most closely with liver tumor samples from a diethylnitrosamine/PB initiation/promotion study than with wild-type mice. However, different gene clusters were observed for chimeric mice with human hepatocytes for Wnt/β-catenin signaling when compared with those of hCAR/hPXR mice, wild-type mice, and liver tumor samples. The results of this study demonstrate clear differences in the effects of PB on hepatocyte RDS and global gene expression between human hepatocytes of chimeric mice and hCAR/hPXR mice, suggesting that the chimeric mouse model is relevant to humans for studies on the hepatic effects of rodent CAR activators whereas the hCAR/hPXR mouse is not.
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Affiliation(s)
| | - Ayako Ohara
- Bioscience Research Laboratory, Sumitomo Chemical Company, Ltd, Konohana-ku, Osaka 554-8558, Japan
| | - Naoya Ozawa
- Bioscience Research Laboratory, Sumitomo Chemical Company, Ltd, Konohana-ku, Osaka 554-8558, Japan
| | | | | | - Yu Okuda
- Environmental Health Science Laboratory
| | - Jun Abe
- Environmental Health Science Laboratory
| | - Samuel M Cohen
- Department of Pathology and Microbiology, Havlik-Wall Professor of Oncology, University of Nebraska Medical Center, Omaha, Nebraska 68198-3135
| | - Brian G Lake
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom
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11
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Yamada T, Cohen SM, Lake BG. Critical evaluation of the human relevance of the mode of action for rodent liver tumor formation by activators of the constitutive androstane receptor (CAR). Crit Rev Toxicol 2021; 51:373-394. [PMID: 34264181 DOI: 10.1080/10408444.2021.1939654] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Many nongenotoxic chemicals have been shown to produce liver tumors in mice and/or rats by a mode of action (MOA) involving activation of the constitutive androstane receptor (CAR). Studies with phenobarbital (PB) and other compounds have identified the key events for this MOA: CAR activation; increased hepatocellular proliferation; altered foci formation; and ultimately the development of adenomas/carcinomas. In terms of human relevance, the pivotal species difference is that CAR activators are mitogenic agents in mouse and rat hepatocytes, but they do not stimulate increased hepatocellular proliferation in humans. This conclusion is supported by substantial in vitro studies with cultured rodent and human hepatocytes and also by in vivo studies with chimeric mice with human hepatocytes. Examination of the literature reveals many similarities in the hepatic effects and species differences between activators of rodent CAR and the peroxisome proliferator-activated receptor alpha (PPARα), with PPARα activators also not being mitogenic agents in human hepatocytes. Overall, a critical analysis of the available data demonstrates that the established MOA for rodent liver tumor formation by PB and other CAR activators is qualitatively not plausible for humans. This conclusion is supported by data from several human epidemiology studies.
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Affiliation(s)
- Tomoya Yamada
- Environmental Health Science Laboratory, Sumitomo Chemical Company, Ltd., Osaka, Japan
| | - Samuel M Cohen
- Department of Pathology and Microbiology, Havlik-Wall Professor of Oncology, University of Nebraska Medical Center, Nebraska Medical Center, Omaha, NE, USA
| | - Brian G Lake
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
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12
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Zeng T, Guan Y, Li YK, Wu Q, Tang XJ, Zeng X, Ling H, Zou J. The DNA replication regulator MCM6: An emerging cancer biomarker and target. Clin Chim Acta 2021; 517:92-98. [PMID: 33609557 DOI: 10.1016/j.cca.2021.02.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/01/2021] [Accepted: 02/05/2021] [Indexed: 01/07/2023]
Abstract
MCM6 is a significant DNA replication regulator that plays a crucial role in sustaining the cell cycle. In many cancer cells, MCM6 expression is enhanced. For example, persistently increased expression of MCM6 promotes the formation, development and progression of hepatocellular carcinoma (HCC). Up- and down-regulation studies have indicated that MCM6 regulates cell cycle, proliferation, metastasis, immune response and the maintenance of the DNA replication system. MCM6 can also regulate downstream signaling such as MEK/ERK thus promoting carcinogenesis. Accordingly, MCM6 may represent a sensitive and specific biomarker to predict adverse progression and poor outcome. Furthermore, inhibition of MCM6 may be an effective cancer treatment. The present review summarizes the latest results on the inactivating and activating functions of MCM6, underlining its function in carcinogenesis. Further studies of the carcinogenic functions of MCM6 may provide novel insight into cancer biology and shed light on new approaches for cancer diagnosis and treatment.
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Affiliation(s)
- Tian Zeng
- Hunan Province Key Laboratory of Tumor Cellular & Molecular Pathology, Cancer Research Institute, University of South China, Hengyang, Hunan 421001, PR China
| | - Yang Guan
- Jiangxi University of Traditional Chinese Medicine, Nanchang, Jiangxi 330000, PR China
| | - Yu-Kun Li
- Hunan Province Key Laboratory of Tumor Cellular & Molecular Pathology, Cancer Research Institute, University of South China, Hengyang, Hunan 421001, PR China
| | - Qing Wu
- Department of Digestive Medical, The Affiliated Nanhua Hospital, University of South China, Hengyang 421002, PR China
| | - Xiao-Jun Tang
- Department of Spinal Surgery, The Second Affiliated Hospital of University of South China, Hengyang, Hunan 421001, PR China
| | - Xin Zeng
- Department of Histology and Embryology, Chongqing Three Gorges Medical College, Wanzhou, Chongqing 404000, PR China
| | - Hui Ling
- Hunan Province Key Laboratory of Tumor Cellular & Molecular Pathology, Cancer Research Institute, University of South China, Hengyang, Hunan 421001, PR China.
| | - Juan Zou
- Hunan Province Key Laboratory of Tumor Cellular & Molecular Pathology, Cancer Research Institute, University of South China, Hengyang, Hunan 421001, PR China.
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13
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Chappell GA, Heintz MM, Haws LC. Transcriptomic analyses of livers from mice exposed to 1,4-dioxane for up to 90 days to assess potential mode(s) of action underlying liver tumor development. Curr Res Toxicol 2021; 2:30-41. [PMID: 34345848 PMCID: PMC8320614 DOI: 10.1016/j.crtox.2021.01.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 01/06/2021] [Accepted: 01/07/2021] [Indexed: 12/11/2022] Open
Abstract
1,4-Dioxane is a volatile organic compound with industrial and commercial applications as a solvent and in the manufacture of other chemicals. 1,4-Dioxane has been demonstrated to induce liver tumors in chronic rodent bioassays conducted at very high doses. The available evidence for 1,4-dioxane-induced liver tumors in rodents aligns with a threshold-dependent mode of action (MOA), with the underlying mechanism being less clear in the mouse than in rats. To gain a better understanding of the underlying molecular mechanisms related to liver tumor development in mice orally exposed to 1,4-dioxane, transcriptomics analysis was conducted on liver tissue collected from a 90-day drinking water study in female B6D2F1/Crl mice (Lafranconi et al., 2020). Using tissue samples from female mice exposed to 1,4-dioxane in the drinking water at concentrations of 0, 40, 200, 600, 2,000 or 6,000 ppm for 7, 28, and 90 days, transcriptomic analyses demonstrate minimal treatment effects on global gene expression at concentrations below 600 ppm. At higher concentrations, genes involved in phase II metabolism and mitotic cell cycle checkpoints were significantly upregulated. There was an overall lack of enrichment of genes related to DNA damage response. The increase in mitotic signaling is most prevalent in the livers of mice exposed to 1,4-dioxane at the highest concentrations for 90 days. This finding aligns with phenotypic changes reported by Lafranconi et al. (2020) after 90-days of exposure to 6,000 ppm 1,4-dioxane in the same tissues. The transcriptomics analysis further supports overarching study findings demonstrating a non-mutagenic, threshold-based, mitogenic MOA for 1,4-dioxane-induced liver tumors.
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Affiliation(s)
- G A Chappell
- ToxStrategies, Inc., Asheville, NC, United States
| | - M M Heintz
- ToxStrategies, Inc., Asheville, NC, United States
| | - L C Haws
- ToxStrategies, Inc., Austin, TX, United States
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14
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Braeuning A, Pavek P. β-catenin signaling, the constitutive androstane receptor and their mutual interactions. Arch Toxicol 2020; 94:3983-3991. [PMID: 33097968 PMCID: PMC7655584 DOI: 10.1007/s00204-020-02935-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 10/08/2020] [Indexed: 12/24/2022]
Abstract
Aberrant signaling through β-catenin is an important determinant of tumorigenesis in rodents as well as in humans. In mice, xenobiotic activators of the constitutive androstane receptor (CAR), a chemo-sensing nuclear receptor, promote liver tumor growth by means of a non-genotoxic mechanism and, under certain conditions, select for hepatocellular tumors which contain activated β-catenin. In normal hepatocytes, interactions of β-catenin and CAR have been demonstrated with respect to the induction of proliferation and drug metabolism-related gene expression. The molecular details of these interactions are still not well understood. Recently it has been hypothesized that CAR might activate β-catenin signaling, thus providing a possible explanation for some of the observed phenomena. Nonetheless, many aspects of the molecular interplay of the two regulators have still not been elucidated. This review briefly summarizes our current knowledge about the interplay of CAR and β-catenin. By taking into account data and observations obtained with different mouse models and employing different experimental approaches, it is shown that published data also contain substantial evidence that xenobiotic activators of CAR do not activate, or do even inhibit signaling through the β-catenin pathway. The review highlights new aspects of possible ways of interaction between the two signaling cascades and will help to stimulate scientific discussion about the crosstalk of β-catenin signaling and the nuclear receptor CAR.
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Affiliation(s)
- Albert Braeuning
- Department Food Safety, German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, 10589, Berlin, Germany.
| | - Petr Pavek
- Department of Pharmacology and Toxicology, Charles University, Faculty of Pharmacy, Heyrovskeho 1203, Hradec Kralove, 500 05, Prague, Czech Republic
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15
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Early microRNA indicators of PPARα pathway activation in the liver. Toxicol Rep 2020; 7:805-815. [PMID: 32642447 PMCID: PMC7334544 DOI: 10.1016/j.toxrep.2020.06.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 06/01/2020] [Accepted: 06/19/2020] [Indexed: 12/29/2022] Open
Abstract
MicroRNAs (miRNAs) are short non-coding RNA species that play key roles in post-transcriptional regulation of gene expression. MiRNAs also serve as a promising source of early biomarkers for different environmental exposures and health effects, although there is limited information linking miRNA changes to specific target pathways. In this study, we measured liver miRNAs in male B6C3F1 mice exposed to a known chemical activator of the peroxisome proliferator-activated receptor alpha (PPARα) pathway, di(2-ethylhexyl) phthalate (DEHP), for 7 and 28 days at concentrations of 0, 750, 1500, 3000, or 6000 ppm in feed. At the highest dose tested, DEHP altered 61 miRNAs after 7 days and 171 miRNAs after 28 days of exposure, with 48 overlapping miRNAs between timepoints. Analysis of these 48 common miRNAs indicated enrichment in PPARα–related targets and other pathways related to liver injury and cancer. Four of the 10 miRNAs exhibiting a clear dose trend were linked to the PPARα pathway: mmu-miRs-125a-5p, -182−5p, -20a−5p, and -378a−3p. mmu-miRs-182−5p and -378a−3p were subsequently measured using digital drop PCR across a dose range for DEHP and two related phthalates with weaker PPARα activity, di-n-octyl phthalate and n-butyl benzyl phthalate, following 7-day exposures. Analysis of mmu-miRs-182−5p and -378a−3p by transcriptional benchmark dose analysis correctly identified DEHP as having the greatest potency. However, benchmark dose estimates for DEHP based on these miRNAs (average 163; range 126−202 mg/kg-day) were higher on average than values for PPARα target genes (average 74; range 29−183 mg/kg-day). These findings identify putative miRNA biomarkers of PPARα pathway activity and suggest that early miRNA changes may be used to stratify chemical potency.
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Key Words
- AIC, Akaike Information Criterion
- ALT, alanine aminotransferase
- AOP, adverse outcome pathway
- AST, aspartate aminotransferase
- Acox1, acyl-Coenzyme A oxidase 1
- Adverse outcome pathway (AOP)
- AhR, aryl hydrocarbon receptor
- BBP, n-butyl benzyl phthalate
- BMD, benchmark dose
- BMDA, apical-based benchmark dose
- BMDL, BMD lower confidence interval
- BMDT, transcriptional-based benchmark dose
- BMR, benchmark response
- BROD, benzyloxyresorufin O-debenzylation
- Benchmark dose (BMD)
- Biomarkers
- CAR, constitutive androstane receptor
- DEGs, differentially expressed genes
- DEHP, di (2-thylhexyl) phthalate
- DEmiRs, differentially expressed miRNAs
- DNOP, di-n-octyl phthalate
- EPA, U.S. Environmental Protection Agency
- EROD, ethoxyresorufin O-dealkylation
- GEO, Gene Expression Omnibus
- HCA, hepatocellular adenoma
- HCC, hepatocellular carcinoma
- Hepatocellular carcinoma
- IPA, Ingenuity Pathway Analysis
- Liver toxicity
- MOA, mode of action
- MicroRNAs
- Mode of action (MOA)
- Nrf2, nuclear receptor erythroid 2-like 2
- POD, point-of-departure
- PPARα, peroxisome proliferator-activated receptor alpha
- PROD, pentoxyresorufin O-depentylation
- PXR, pregnane X receptor
- Peroxisome proliferator-activated receptor alpha (PPARα)
- Phthalate
- SDH, sorbitol dehydrogenase
- TMM, trimmed mean of M-values
- ddPCR, droplet digital polymerase chain reaction
- mRNA, messenger RNA
- miRNAs, microRNAs
- mtDNA, mitochondrial
- rRNA, ribosomal RNA
- smallRNA-seq, small RNA sequencing
- tRNA, transfer RNA
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The Connection of Azole Fungicides with Xeno-Sensing Nuclear Receptors, Drug Metabolism and Hepatotoxicity. Cells 2020; 9:cells9051192. [PMID: 32403288 PMCID: PMC7290820 DOI: 10.3390/cells9051192] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/07/2020] [Accepted: 05/08/2020] [Indexed: 12/21/2022] Open
Abstract
Azole fungicides, especially triazole compounds, are widely used in agriculture and as pharmaceuticals. For a considerable number of agricultural azole fungicides, the liver has been identified as the main target organ of toxicity. A number of previous studies points towards an important role of nuclear receptors such as the constitutive androstane receptor (CAR), the pregnane-X-receptor (PXR), or the aryl hydrocarbon receptor (AHR), within the molecular pathways leading to hepatotoxicity of these compounds. Nuclear receptor-mediated hepatic effects may comprise rather adaptive changes such as the induction of drug-metabolizing enzymes, to hepatocellular hypertrophy, histopathologically detectable fatty acid changes, proliferation of hepatocytes, and the promotion of liver tumors. Here, we present a comprehensive review of the current knowledge of the interaction of major agricultural azole-class fungicides with the three nuclear receptors CAR, PXR, and AHR in vivo and in vitro. Nuclear receptor activation profiles of the azoles are presented and related to histopathological findings from classic toxicity studies. Important issues such as species differences and multi-receptor agonism and the consequences for data interpretation and risk assessment are discussed.
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17
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Karri K, Waxman DJ. Widespread Dysregulation of Long Noncoding Genes Associated With Fatty Acid Metabolism, Cell Division, and Immune Response Gene Networks in Xenobiotic-exposed Rat Liver. Toxicol Sci 2020; 174:291-310. [PMID: 31926019 PMCID: PMC7098378 DOI: 10.1093/toxsci/kfaa001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Xenobiotic exposure dysregulates hundreds of protein-coding genes in mammalian liver, impacting many physiological processes and inducing diverse toxicological responses. Little is known about xenobiotic effects on long noncoding RNAs (lncRNAs), many of which have important regulatory functions. Here, we present a computational framework to discover liver-expressed, xenobiotic-responsive lncRNAs (xeno-lncs) with strong functional, gene regulatory potential and elucidate the impact of xenobiotic exposure on their gene regulatory networks. We assembled the long noncoding transcriptome of xenobiotic-exposed rat liver using RNA-seq datasets from male rats treated with 27 individual chemicals, representing 7 mechanisms of action (MOAs). Ortholog analysis was combined with coexpression data and causal inference methods to infer lncRNA function and deduce gene regulatory networks, including causal effects of lncRNAs on protein-coding gene expression and biological pathways. We discovered > 1400 liver-expressed xeno-lncs, many with human and/or mouse orthologs. Xenobiotics representing different MOAs often regulated common xeno-lnc targets: 123 xeno-lncs were dysregulated by ≥ 10 chemicals, and 5 xeno-lncs responded to ≥ 20 of the 27 chemicals investigated; 81 other xeno-lncs served as MOA-selective markers of xenobiotic exposure. Xeno-lnc-protein-coding gene coexpression regulatory network analysis identified xeno-lncs closely associated with exposure-induced perturbations of hepatic fatty acid metabolism, cell division, or immune response pathways, and with apoptosis or cirrhosis. We also identified hub and bottleneck lncRNAs, which are expected to be key regulators of gene expression. This work elucidates extensive networks of xeno-lnc-protein-coding gene interactions and provides a framework for understanding the widespread transcriptome-altering actions of foreign chemicals in a key-responsive mammalian tissue.
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Affiliation(s)
- Kritika Karri
- Department of Biology and Bioinformatics Program, Boston University, Boston, Massachusetts
| | - David J Waxman
- Department of Biology and Bioinformatics Program, Boston University, Boston, Massachusetts
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18
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Shizu R, Yoshinari K. Nuclear receptor CAR-mediated liver cancer and its species differences. Expert Opin Drug Metab Toxicol 2020; 16:343-351. [PMID: 32202166 DOI: 10.1080/17425255.2020.1746268] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Introduction: The nuclear receptor CAR plays an important role in the regulation of hepatic responses to xenobiotic exposure, including the induction of hepatocyte proliferation and chemical carcinogenesis. Phenobarbital, a well-known liver cancer promoter, has been found to promote hepatocyte proliferation via CAR activation. However, the molecular mechanisms by which CAR induces liver carcinogenesis remain unknown. In addition, it is believed that CAR-mediated liver carcinogenesis shows a species difference; phenobarbital treatment induces hepatocyte proliferation and liver cancer in rodents but not in humans. However, the mechanisms are also unknown.Areas covered: Several reports indicate that the key oncogenic signaling pathways Wnt/β-catenin and Hippo/YAP are involved in CAR-mediated liver carcinogenesis. We introduce current data about the possible molecular mechanisms involved in CAR-mediated liver carcinogenesis and species differences by focusing on these two signaling pathways.Expert opinion: CAR may activate both the Wnt/β-catenin and Hippo/YAP signaling pathways. The synergistic activation of both signaling pathways seems to be important for CAR-mediated liver cancer development. Low homology between the ligand binding domains of human CAR and rodent CAR might cause species differences in the interactions with proteins that control the Wnt/β-catenin and Hippo/YAP pathways as well as liver cancer induction.
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Affiliation(s)
- Ryota Shizu
- Laboratory of Molecular Toxicology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Kouichi Yoshinari
- Laboratory of Molecular Toxicology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
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19
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Yoshinari K. Role of Nuclear Receptors PXR and CAR in Xenobiotic-Induced Hepatocyte Proliferation and Chemical Carcinogenesis. Biol Pharm Bull 2020; 42:1243-1252. [PMID: 31366862 DOI: 10.1248/bpb.b19-00267] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nuclear receptors pregnane X receptor (PXR) and constitutive active/androstane receptor (CAR) are xenobiotic-responsible transcriptional factors that belong to the same subfamily and are expressed abundantly in the liver. They play crucial roles in various liver functions including xenobiotic disposition and energy metabolism. CAR is also involved in xenobiotic-induced hepatocyte proliferation and hepatocarcinogenesis in rodents. However, there are some open questions on the association between chemical carcinogenesis and these nuclear receptors. These include the molecular mechanism for CAR-mediated hepatocyte proliferation and hepatocarcinogenesis. Another important question is whether PXR is associated with hepatocyte proliferation. We have recently reported a novel and unique function of PXR associated with murine hepatocyte proliferation: PXR activation alone does not induce hepatocyte proliferation but accelerates hepatocyte proliferation induced by various types of stimuli including CAR- or peroxisome proliferator-activated receptor alpha activating compounds, liver injury, and growth factors. We have also reported a role of yes-associated protein (YAP), a transcriptional cofactor controlling organ size and cell growth under the Hippo pathway, in CAR-mediated hepatocyte proliferation in mice. In this review, I will introduce our recent results as well as related studies on the roles of PXR and CAR in xenobiotic-induced hepatocyte proliferation and their molecular mechanisms.
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Affiliation(s)
- Kouichi Yoshinari
- Laboratory of Molecular Toxicology, School of Pharmaceutical Sciences, University of Shizuoka
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20
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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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21
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Chen B, Wang M, Gan L, Zhang B, Desnick RJ, Yasuda M. Characterization of the hepatic transcriptome following phenobarbital induction in mice with AIP. Mol Genet Metab 2019; 128:382-390. [PMID: 30777612 PMCID: PMC6612539 DOI: 10.1016/j.ymgme.2018.12.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 12/03/2018] [Accepted: 12/24/2018] [Indexed: 12/12/2022]
Abstract
Acute Intermittent Porphyria (AIP), an autosomal dominant hepatic disorder, results from hydroxymethylbilane synthase (HMBS) mutations that decrease the encoded enzymatic activity, thereby predisposing patients to life-threatening acute neurovisceral attacks. The ~1% penetrance of AIP suggests that other genetic factors modulate the onset and severity of the acute attacks. Here, we characterized the hepatic transcriptomic response to phenobarbital (PB) administration in AIP mice, which mimics the biochemical attacks of AIP. At baseline, the mRNA profiles of 14,138 hepatic genes prior to treatment were remarkably similar between AIP and the congenic wild-type (WT) mice. After PB treatment (~120 mg/kg x 3d), 1347 and 1120 genes in AIP mice and 422 and 404 genes in WT mice were uniquely up- and down-regulated, respectively, at a False Discovery Rate < 0.05. As expected, the ALAS1 expression increased 4.5-fold and 15.9-fold in the WT and AIP mice, respectively. ALA-dehydrogenase also was induced ~1.7-fold in PB-induced AIP mice, but was unchanged in PB-induced WT mice. There was no statistically significant difference in the overall expression of 155 hepatic cytochrome P450 enzymes, although Cyp2c40, Cyp2c68, Cyp2c69, Mgst3 were upregulated only in PB-induced AIP mice (>1.9-fold) and Cyp21a1 was upregulated only in PB-induced WT mice (>9-fold). Notably, the genes differentially expressed in induced AIP mice were enriched in circadian rhythm, mitochondria biogenesis and electron transport, suggesting these pathways were involved in AIP mice responding to PB treatment. These results advance our understanding of the hepatic metabolic changes in PB-induced AIP mice and have implications in the pathogenesis of AIP acute attacks.
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Affiliation(s)
- Brenden Chen
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Minghui Wang
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Lin Gan
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Bin Zhang
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Robert J Desnick
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Makiko Yasuda
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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22
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Vitobello A, Perner J, Beil J, Zhu J, Del Río-Espínola A, Morawiec L, Westphal M, Dubost V, Altorfer M, Naumann U, Mueller A, Kapur K, Borowsky M, Henderson C, Wolf CR, Schwarz M, Moggs J, Terranova R. Drug-induced chromatin accessibility changes associate with sensitivity to liver tumor promotion. Life Sci Alliance 2019; 2:e201900461. [PMID: 31615920 PMCID: PMC6795216 DOI: 10.26508/lsa.201900461] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 09/26/2019] [Accepted: 09/26/2019] [Indexed: 12/27/2022] Open
Abstract
Liver cancer susceptibility varies amongst humans and between experimental animal models because of multiple genetic and epigenetic factors. The molecular characterization of such susceptibilities has the potential to enhance cancer risk assessment of xenobiotic exposures and disease prevention strategies. Here, using DNase I hypersensitivity mapping coupled with transcriptomic profiling, we investigate perturbations in cis-acting gene regulatory elements associated with the early stages of phenobarbital (PB)-mediated liver tumor promotion in susceptible versus resistant mouse strains (B6C3F1 versus C57BL/6J). Integrated computational analyses of strain-selective changes in liver chromatin accessibility underlying PB response reveal differential epigenetic regulation of molecular pathways associated with PB-mediated tumor promotion, including Wnt/β-catenin signaling. Complementary transcription factor motif analyses reveal mouse strain-selective gene regulatory networks and a novel role for Stat, Smad, and Fox transcription factors in the early stages of PB-mediated tumor promotion. Mapping perturbations in cis-acting gene regulatory elements provides novel insights into the molecular basis for susceptibility to xenobiotic-induced rodent liver tumor promotion and has the potential to enhance mechanism-based cancer risk assessments of xenobiotic exposures.
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Affiliation(s)
- Antonio Vitobello
- Novartis Institutes for BioMedical Research (NIBR), Basel, Switzerland
- Inserm, Unité Mixte de Recherche (UMR) 1231, Université de Bourgogne-Franche Comté, Dijon, France
| | - Juliane Perner
- Novartis Institutes for BioMedical Research (NIBR), Basel, Switzerland
| | - Johanna Beil
- Novartis Institutes for BioMedical Research (NIBR), Basel, Switzerland
| | | | | | - Laurent Morawiec
- Novartis Institutes for BioMedical Research (NIBR), Basel, Switzerland
| | | | - Valérie Dubost
- Novartis Institutes for BioMedical Research (NIBR), Basel, Switzerland
| | - Marc Altorfer
- Novartis Institutes for BioMedical Research (NIBR), Basel, Switzerland
| | - Ulrike Naumann
- Novartis Institutes for BioMedical Research (NIBR), Basel, Switzerland
| | - Arne Mueller
- Novartis Institutes for BioMedical Research (NIBR), Basel, Switzerland
| | - Karen Kapur
- Novartis Institutes for BioMedical Research (NIBR), Basel, Switzerland
| | | | - Colin Henderson
- School of Medicine, Jacqui Wood Cancer Centre, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
- Innovative Medicines Initiative MARCAR Consortium (http://www.imi-marcar.eu/index.php)
| | - C Roland Wolf
- School of Medicine, Jacqui Wood Cancer Centre, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
- Innovative Medicines Initiative MARCAR Consortium (http://www.imi-marcar.eu/index.php)
| | - Michael Schwarz
- Department of Toxicology, University of Tübingen, Tübingen, Germany
- Innovative Medicines Initiative MARCAR Consortium (http://www.imi-marcar.eu/index.php)
| | - Jonathan Moggs
- Novartis Institutes for BioMedical Research (NIBR), Basel, Switzerland
- Innovative Medicines Initiative MARCAR Consortium (http://www.imi-marcar.eu/index.php)
| | - Rémi Terranova
- Novartis Institutes for BioMedical Research (NIBR), Basel, Switzerland
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23
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Li L, Welch MA, Li Z, Mackowiak B, Heyward S, Swaan PW, Wang H. Mechanistic Insights of Phenobarbital-Mediated Activation of Human but Not Mouse Pregnane X Receptor. Mol Pharmacol 2019; 96:345-354. [PMID: 31436536 PMCID: PMC6701513 DOI: 10.1124/mol.119.116616] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 07/07/2019] [Indexed: 12/12/2022] Open
Abstract
Phenobarbital (PB), a broadly used antiseizure drug, was the first to be characterized as an inducer of cytochrome P450 by activation of the constitutive androstane receptor (CAR). Although PB is recognized as a conserved CAR activator among species via a well-documented indirect activation mechanism, conflicting results have been reported regarding PB regulation of the pregnane X receptor (PXR), a sister receptor of CAR, and the underlying mechanisms remain elusive. Here, we show that in a human CAR (hCAR)-knockout (KO) HepaRG cell line, PB significantly induces the expression of CYP2B6 and CYP3A4, two shared target genes of hCAR and human PXR (hPXR). In human primary hepatocytes and hCAR-KO HepaRG cells, PB-induced expression of CYP3A4 was markedly repressed by genetic knockdown or pharmacological inhibition of hPXR. Mechanistically, PB concentration dependently activates hPXR but not its mouse counterpart in cell-based luciferase assays. Mammalian two-hybrid assays demonstrated that PB selectively increases the functional interaction between the steroid receptor coactivator-1 and hPXR but not mouse PXR. Moreover, surface plasmon resonance binding affinity assay showed that PB directly binds to the ligand binding domain of hPXR (KD = 1.42 × 10-05). Structure-activity analysis further revealed that the amino acid tryptophan-299 within the ligand binding pocket of hPXR plays a key role in the agonistic binding of PB and mutation of tryptophan-299 disrupts PB activation of hPXR. Collectively, these data reveal that PB, a selective mouse CAR activator, activates both hCAR and hPXR, and provide novel mechanistic insights for PB-mediated activation of hPXR.
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Affiliation(s)
- Linhao Li
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland (L.L., M.A.W., Z.L., B.M., P.W.S., H.W.); and BioIVT, Halethorpe, Maryland (S.H.)
| | - Matthew A Welch
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland (L.L., M.A.W., Z.L., B.M., P.W.S., H.W.); and BioIVT, Halethorpe, Maryland (S.H.)
| | - Zhihui Li
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland (L.L., M.A.W., Z.L., B.M., P.W.S., H.W.); and BioIVT, Halethorpe, Maryland (S.H.)
| | - Bryan Mackowiak
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland (L.L., M.A.W., Z.L., B.M., P.W.S., H.W.); and BioIVT, Halethorpe, Maryland (S.H.)
| | - Scott Heyward
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland (L.L., M.A.W., Z.L., B.M., P.W.S., H.W.); and BioIVT, Halethorpe, Maryland (S.H.)
| | - Peter W Swaan
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland (L.L., M.A.W., Z.L., B.M., P.W.S., H.W.); and BioIVT, Halethorpe, Maryland (S.H.)
| | - Hongbing Wang
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland (L.L., M.A.W., Z.L., B.M., P.W.S., H.W.); and BioIVT, Halethorpe, Maryland (S.H.)
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24
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McMahon M, Ding S, Jimenez LA, Terranova R, Gerard MA, Vitobello A, Moggs J, Henderson CJ, Wolf CR. Constitutive androstane receptor 1 is constitutively bound to chromatin and 'primed' for transactivation in hepatocytes. Mol Pharmacol 2019; 95:97-105. [PMID: 30361333 PMCID: PMC6277922 DOI: 10.1124/mol.118.113555] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 10/19/2018] [Indexed: 12/15/2022] Open
Abstract
The constitutive androstane receptor (CAR) is a xenobiotic sensor expressed in hepatocytes that activates genes involved in drug metabolism, lipid homeostasis, and cell proliferation. Much progress has been made in understanding the mechanism of activation of human CAR by drugs and xenobiotics. However, many aspects of the activation pathway remain to be elucidated. In this report, we have used viral constructs to express human CAR, its splice variants, and mutant CAR forms in hepatocytes from Car-/- mice in vitro and in vivo. We demonstrate CAR expression rescued the ability of Car-/- hepatocytes to respond to a wide range of CAR activators including phenobarbital. Additionally, two major splice isoforms of human CAR, CAR2 and CAR3, were inactive with almost all the agents tested. In contrast to the current model of CAR activation, ectopic CAR1 is constitutively localized in the nucleus and is loaded onto Cyp2b10 gene in the absence of an inducing agent. In studies to elucidate the role of threonine T38 in CAR regulation, we found that the T38D mutant was inactive even in the presence of CAR activators. However, the T38A mutant was activated by CAR inducers, showing that T38 is not essential for CAR activation. Also, using the inhibitor erlotinib, we could not confirm a role for the epidermal growth factor receptor in CAR regulation. Our data suggest that CAR is constitutively bound to gene regulatory regions and is regulated by exogenous agents through a mechanism which involves protein phosphorylation in the nucleus.
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Affiliation(s)
- Michael McMahon
- School of Medicine, Jacqui Wood Cancer Centre, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom (M.M., S.D., L.A.J., C.J.H., C.R.W.) and Preclinical Safety, Translational Medicine, Novartis Institutes for BioMedical Research, Basel, Switzerland (R.T., M.-A.G., A.V., J.M.)
| | - Shaohong Ding
- School of Medicine, Jacqui Wood Cancer Centre, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom (M.M., S.D., L.A.J., C.J.H., C.R.W.) and Preclinical Safety, Translational Medicine, Novartis Institutes for BioMedical Research, Basel, Switzerland (R.T., M.-A.G., A.V., J.M.)
| | - Lourdes Acosta Jimenez
- School of Medicine, Jacqui Wood Cancer Centre, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom (M.M., S.D., L.A.J., C.J.H., C.R.W.) and Preclinical Safety, Translational Medicine, Novartis Institutes for BioMedical Research, Basel, Switzerland (R.T., M.-A.G., A.V., J.M.)
| | - Remi Terranova
- School of Medicine, Jacqui Wood Cancer Centre, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom (M.M., S.D., L.A.J., C.J.H., C.R.W.) and Preclinical Safety, Translational Medicine, Novartis Institutes for BioMedical Research, Basel, Switzerland (R.T., M.-A.G., A.V., J.M.)
| | - Marie-Apolline Gerard
- School of Medicine, Jacqui Wood Cancer Centre, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom (M.M., S.D., L.A.J., C.J.H., C.R.W.) and Preclinical Safety, Translational Medicine, Novartis Institutes for BioMedical Research, Basel, Switzerland (R.T., M.-A.G., A.V., J.M.)
| | - Antonio Vitobello
- School of Medicine, Jacqui Wood Cancer Centre, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom (M.M., S.D., L.A.J., C.J.H., C.R.W.) and Preclinical Safety, Translational Medicine, Novartis Institutes for BioMedical Research, Basel, Switzerland (R.T., M.-A.G., A.V., J.M.)
| | - Jonathan Moggs
- School of Medicine, Jacqui Wood Cancer Centre, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom (M.M., S.D., L.A.J., C.J.H., C.R.W.) and Preclinical Safety, Translational Medicine, Novartis Institutes for BioMedical Research, Basel, Switzerland (R.T., M.-A.G., A.V., J.M.)
| | - Colin J Henderson
- School of Medicine, Jacqui Wood Cancer Centre, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom (M.M., S.D., L.A.J., C.J.H., C.R.W.) and Preclinical Safety, Translational Medicine, Novartis Institutes for BioMedical Research, Basel, Switzerland (R.T., M.-A.G., A.V., J.M.)
| | - C Roland Wolf
- School of Medicine, Jacqui Wood Cancer Centre, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom (M.M., S.D., L.A.J., C.J.H., C.R.W.) and Preclinical Safety, Translational Medicine, Novartis Institutes for BioMedical Research, Basel, Switzerland (R.T., M.-A.G., A.V., J.M.)
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25
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Guo J, Ito S, Nguyen HT, Yamamoto K, Iwata H. Effects on the hepatic transcriptome of chicken embryos in ovo exposed to phenobarbital. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 160:94-103. [PMID: 29793206 DOI: 10.1016/j.ecoenv.2018.05.033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 05/11/2018] [Accepted: 05/12/2018] [Indexed: 06/08/2023]
Abstract
This work aimed at evaluating the toxic effects of in ovo exposure to phenobarbital (PB) and unveiling the mode of action by transcriptome analysis in the embryonic liver of a model avian species, chicken (Gallus gallus). Embryos were initially treated with saline or 1 μg PB /g egg at Hamburger Hamilton Stage (HHS) 1 (1st day), followed by 20 days of incubation to HHS 46. At 21st day, chicks that pipped successfully were euthanized and dissected for assessing the PB caused effects on phenotypes and the liver transcriptome in both genders. In the PB treatment group, a 7% attenuation in tarsus length was found in females. While no adverse phenotypic effect on the liver somatic index (LSI) was observed, PB caused significant changes in the expressions of 52 genes in males and 516 genes in females (False Discovery Rate < 0.2, p value < 0.05, and absolute fold change > 2). PB exposure modulated the genes primarily enriched in the biological pathways of the cancer, cardiac development, immune response, lipid metabolism, and skeletal development in both genders, and altered expressions of genes related to the cellular process and neural development in females. However, mRNA expressions of chicken xenobiotic receptor (CXR)-mediated CYP genes were not induced in the PB treatment groups, regardless of males and females. On the contrary, PB exposure repressed the mRNA expressions of CYP2AC2 in males and CYP2R1, CYP3A37, and CYP8B1 in females. Although transcription factors (TFs) including SREBF1 and COUP-TFII were predicted to be commonly activated in both genders, some TFs were activated in a gender-dependent manner, such as PPARa in males and BRCA1 and IRF9 in females. Taken together, our results provided an insight into the mode of action of PB on the chicken embryos.
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Affiliation(s)
- Jiahua Guo
- Center for Marine Environmental Studies, Ehime University, Bunkyo-cho 2-5, Matsuyama, Ehime prefecture, 790-8577 Japan
| | - Shohei Ito
- Center for Marine Environmental Studies, Ehime University, Bunkyo-cho 2-5, Matsuyama, Ehime prefecture, 790-8577 Japan
| | - Hoa Thanh Nguyen
- Center for Marine Environmental Studies, Ehime University, Bunkyo-cho 2-5, Matsuyama, Ehime prefecture, 790-8577 Japan
| | - Kimika Yamamoto
- Center for Marine Environmental Studies, Ehime University, Bunkyo-cho 2-5, Matsuyama, Ehime prefecture, 790-8577 Japan
| | - Hisato Iwata
- Center for Marine Environmental Studies, Ehime University, Bunkyo-cho 2-5, Matsuyama, Ehime prefecture, 790-8577 Japan.
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26
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Moggs J, Terranova R. Chromatin dynamics underlying latent responses to xenobiotics. Toxicol Res (Camb) 2018; 7:606-617. [PMID: 30090610 PMCID: PMC6062062 DOI: 10.1039/c7tx00317j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 02/26/2018] [Indexed: 11/21/2022] Open
Abstract
Pleiotropic xenobiotics can trigger dynamic alterations in mammalian chromatin structure and function but many of these are likely non-adverse and simply reflect short-term changes in DNA transactions underlying normal homeostatic, adaptive and protective cellular responses. However, it is plausible that a subset of xenobiotic-induced perturbations of somatic tissue or germline epigenomes result in delayed-onset and long-lasting adverse effects, in particular if they occur during critical stages of growth and development. These could include reprogramming, dedifferentiation, uncontrolled growth, and cumulative toxicity effects through molecular memory of prior xenobiotic exposures or altered susceptibility to subsequent xenobiotic exposures. Here we discuss the current evidence for epigenetic mechanisms underlying latent responses to xenobiotics, and the potential for identifying molecular epigenetic changes that are prodromal to overt morphologic or functional toxicity phenotypes.
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Affiliation(s)
- Jonathan Moggs
- Preclinical Safety , Translational Medicine , Novartis Institutes for BioMedical Research , Basel , Switzerland
| | - Rémi Terranova
- Preclinical Safety , Translational Medicine , Novartis Institutes for BioMedical Research , Basel , Switzerland
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27
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Yamada T. Case examples of an evaluation of the human relevance of the pyrethroids/pyrethrins-induced liver tumours in rodents based on the mode of action. Toxicol Res (Camb) 2018; 7:681-696. [PMID: 30090614 PMCID: PMC6062351 DOI: 10.1039/c7tx00288b] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 01/10/2018] [Indexed: 01/01/2023] Open
Abstract
Rodent carcinogenicity studies are useful for screening for human carcinogens but they are not perfect. Some modes of action (MOAs) lead to cancers in both experimental rodents and humans, but others that lead to cancers in rodents do not do so in humans. Therefore, analysing the MOAs by which chemicals produce tumours in rodents and determining the relevance of such tumour data for human risk are critical. Recently, experimental data were obtained as case examples of an evaluation of the human relevance of pyrethroid (metofluthrin and momfluorothrin)- and pyrethrins-induced liver tumours in rats based on MOA. The MOA analysis, based on the International Programme on Chemical Safety (IPCS) framework, concluded that experimental data strongly support that the postulated MOA for metofluthrin-, momfluorothrin- and pyrethrins-produced rat hepatocellular tumours is mediated by constitutive androstane receptor (CAR) activation. Since metofluthrin and momfluorothrin are close structural analogues, reproducible outcomes for both chemicals provide confidence in the MOA findings. Furthermore, cultured human hepatocyte studies and humanized chimeric mouse liver studies demonstrated species difference between human hepatocytes (refractory to the mitogenic effects of these compounds) and rat hepatocytes (sensitive to their mitogenic effects). These data strongly support the hypothesis that the CAR-mediated MOA for liver tumorigenesis is of low carcinogenic risk for humans. In this research, in addition to cultured human hepatocyte studies, the usefulness of the humanized chimeric liver mouse models was clearly demonstrated. These data substantially influenced decisions in regulatory toxicology. In this review I comprehensively discuss the human relevance of the CAR-mediated MOA for rodent liver tumorigenesis based on published information, including our recent molecular research on CAR-mediated MOA.
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Affiliation(s)
- Tomoya Yamada
- Environmental Health Science Laboratory , Sumitomo Chemical Co. , Ltd , 1-98 , 3-Chome , Kasugade-Naka , Konohana-ku , Osaka 554-8558 , Japan . ; ; Tel: +81-66466-5322
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28
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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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29
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Lodato NJ, Melia T, Rampersaud A, Waxman DJ. Sex-Differential Responses of Tumor Promotion-Associated Genes and Dysregulation of Novel Long Noncoding RNAs in Constitutive Androstane Receptor-Activated Mouse Liver. Toxicol Sci 2018; 159:25-41. [PMID: 28903501 DOI: 10.1093/toxsci/kfx114] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Xenobiotic agonists of constitutive androstane receptor (CAR) induce many hepatic drug metabolizing enzymes, but following prolonged exposure, promote hepatocellular carcinoma, most notably in male mouse liver. Here, we used nuclear RNA-seq to characterize global changes in the mouse liver transcriptome following exposure to the CAR-specific agonist ligand 1,4-bis-[2-(3,5-dichloropyridyloxy)]benzene (TCPOBOP), including changes in novel long noncoding RNAs that may contribute to xenobiotic-induced pathophysiology. Protein-coding genes dysregulated by 3 h TCPOBOP exposure were strongly enriched in KEGG pathways of xenobiotic and drug metabolism, with stronger and more extensive gene responses observed in female than male liver. After 27 h TCPOBOP exposure, the number of responsive genes increased >8-fold in males, where the top enriched pathways and their upstream regulators expanded to include factors implicated in cell cycle dysregulation and hepatocellular carcinoma progression (cyclin-D1, oncogenes E2f, Yap, Rb, Myc, and proto-oncogenes β-catenin, FoxM1, FoxO1, all predicted to be activated by TCPOBOP in male but not female liver; and tumor suppressors p21 and p53, both predicted to be inhibited). Upstream regulators uniquely associated with 3 h TCPOBOP-exposed females include TNF/NFkB pathway members, which negatively regulate CAR-dependent proliferative responses and may contribute to the relative resistance of female liver to TCPOBOP-induced tumor promotion. These responses may be modified by the many long noncoding liver RNAs we show are dysregulated by TCPOBOP or pregnane-X-receptor agonist exposure, including lncRNAs proximal to CAR target genes Cyp2b10, Por, and Alas1. These data provide a comprehensive view of the CAR-regulated transcriptome and give insight into the mechanism of sex-biased susceptibility to CAR-dependent mouse liver tumorigenesis.
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Affiliation(s)
- Nicholas J Lodato
- Department of Biology and Bioinformatics Program, Boston University, Boston, Massachusetts 02215
| | - Tisha Melia
- Department of Biology and Bioinformatics Program, Boston University, Boston, Massachusetts 02215
| | - Andy Rampersaud
- Department of Biology and Bioinformatics Program, Boston University, Boston, Massachusetts 02215
| | - David J Waxman
- Department of Biology and Bioinformatics Program, Boston University, Boston, Massachusetts 02215
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30
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Pouché L, Vitobello A, Römer M, Glogovac M, MacLeod AK, Ellinger-Ziegelbauer H, Westphal M, Dubost V, Stiehl DP, Dumotier B, Fekete A, Moulin P, Zell A, Schwarz M, Moreno R, Huang JTJ, Elcombe CR, Henderson CJ, Roland Wolf C, Moggs JG, Terranova R. Xenobiotic CAR Activators Induce Dlk1-Dio3 Locus Noncoding RNA Expression in Mouse Liver. Toxicol Sci 2018; 158:367-378. [PMID: 28541575 DOI: 10.1093/toxsci/kfx104] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Derisking xenobiotic-induced nongenotoxic carcinogenesis (NGC) represents a significant challenge during the safety assessment of chemicals and therapeutic drugs. The identification of robust mechanism-based NGC biomarkers has the potential to enhance cancer hazard identification. We previously demonstrated Constitutive Androstane Receptor (CAR) and WNT signaling-dependent up-regulation of the pluripotency associated Dlk1-Dio3 imprinted gene cluster noncoding RNAs (ncRNAs) in the liver of mice treated with tumor-promoting doses of phenobarbital (PB). Here, we have compared phenotypic, transcriptional ,and proteomic data from wild-type, CAR/PXR double knock-out and CAR/PXR double humanized mice treated with either PB or chlordane, and show that hepatic Dlk1-Dio3 locus long ncRNAs are upregulated in a CAR/PXR-dependent manner by two structurally distinct CAR activators. We further explored the specificity of Dlk1-Dio3 locus ncRNAs as hepatic NGC biomarkers in mice treated with additional compounds working through distinct NGC modes of action. We propose that up-regulation of Dlk1-Dio3 cluster ncRNAs can serve as an early biomarker for CAR activator-induced nongenotoxic hepatocarcinogenesis and thus may contribute to mechanism-based assessments of carcinogenicity risk for chemicals and novel therapeutics.
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Affiliation(s)
- Lucie Pouché
- Preclinical Safety, Translational Medicine, Novartis Institutes for Biomedical Research, CH-4057 Basel, Switzerland
| | - Antonio Vitobello
- Preclinical Safety, Translational Medicine, Novartis Institutes for Biomedical Research, CH-4057 Basel, Switzerland
| | - Michael Römer
- Department of Computer Science, University of Tübingen, 72076 Tübingen, Germany
| | - Milica Glogovac
- Novartis Business Services, Novartis Pharma, CH-4057 Basel, Switzerland
| | - A Kenneth MacLeod
- Division of Cancer Research, Jacqui Wood Cancer Centre, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, UK
| | | | - Magdalena Westphal
- Preclinical Safety, Translational Medicine, Novartis Institutes for Biomedical Research, CH-4057 Basel, Switzerland
| | - Valérie Dubost
- Preclinical Safety, Translational Medicine, Novartis Institutes for Biomedical Research, CH-4057 Basel, Switzerland
| | - Daniel Philipp Stiehl
- Preclinical Safety, Translational Medicine, Novartis Institutes for Biomedical Research, CH-4057 Basel, Switzerland
| | - Bérengère Dumotier
- Preclinical Safety, Translational Medicine, Novartis Institutes for Biomedical Research, CH-4057 Basel, Switzerland
| | - Alexander Fekete
- Preclinical Safety, Translational Medicine, Novartis Institutes for Biomedical Research, Cambridge, Massachusetts 02139
| | - Pierre Moulin
- Preclinical Safety, Translational Medicine, Novartis Institutes for Biomedical Research, CH-4057 Basel, Switzerland
| | - Andreas Zell
- Department of Computer Science, University of Tübingen, 72076 Tübingen, Germany
| | - Michael Schwarz
- Department of Toxicology, University of Tübingen, 72074 Tübingen, Germany
| | - Rita Moreno
- Division of Cancer Research, Jacqui Wood Cancer Centre, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK
| | - Jeffrey T J Huang
- Biomarker and Drug Analysis Core Facility, School of Medicine, Jacqui Wood Cancer Centre, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK
| | | | - Colin J Henderson
- Division of Cancer Research, Jacqui Wood Cancer Centre, Medical Research Institute, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK
| | - C Roland Wolf
- Division of Cancer Research, Jacqui Wood Cancer Centre, Medical Research Institute, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK
| | - Jonathan G Moggs
- Preclinical Safety, Translational Medicine, Novartis Institutes for Biomedical Research, CH-4057 Basel, Switzerland
| | - Rémi Terranova
- Preclinical Safety, Translational Medicine, Novartis Institutes for Biomedical Research, CH-4057 Basel, Switzerland
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31
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Meehan RR, Thomson JP, Lentini A, Nestor CE, Pennings S. DNA methylation as a genomic marker of exposure to chemical and environmental agents. Curr Opin Chem Biol 2018; 45:48-56. [PMID: 29505975 DOI: 10.1016/j.cbpa.2018.02.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 02/07/2018] [Accepted: 02/12/2018] [Indexed: 02/06/2023]
Abstract
Recent progress in interpreting comprehensive genetic and epigenetic profiles for human cellular states has contributed new insights into the developmental origins of disease, elucidated novel signalling pathways and enhanced drug discovery programs. A similar comprehensive approach to decoding the epigenetic readouts from chemical challenges in vivo would yield new paradigms for monitoring and assessing environmental exposure in model systems and humans.
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Affiliation(s)
- Richard R Meehan
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, UK.
| | - John P Thomson
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, UK
| | - Antonio Lentini
- Department of Clinical and Experimental Medicine, Linköping University, Linköping SE 58183, Sweden
| | - Colm E Nestor
- Department of Clinical and Experimental Medicine, Linköping University, Linköping SE 58183, Sweden.
| | - Sari Pennings
- Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, 47 Little France Crescent, EH16 4TJ, UK.
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32
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Bogen KT. Biphasic hCAR Inhibition-Activation by Two Aminoazo Liver Carcinogens. NUCLEAR RECEPTOR RESEARCH 2018. [DOI: 10.11131/2018/101321] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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33
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Haines C, Elcombe BM, Chatham LR, Vardy A, Higgins LG, Elcombe CR, Lake BG. Comparison of the effects of sodium phenobarbital in wild type and humanized constitutive androstane receptor (CAR)/pregnane X receptor (PXR) mice and in cultured mouse, rat and human hepatocytes. Toxicology 2018; 396-397:23-32. [PMID: 29425889 DOI: 10.1016/j.tox.2018.02.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/24/2018] [Accepted: 02/01/2018] [Indexed: 10/18/2022]
Abstract
Phenobarbital (PB), a constitutive androstane receptor (CAR) activator, produces liver tumours in rodents by a mitogenic mode of action involving CAR activation. In this study, the hepatic effects of sodium phenobarbital (NaPB) were compared in male C57BL/6J wild type (WT) mice and in humanized mice, where both the mouse CAR and pregnane X receptor (PXR) have been replaced by their human counterparts (hCAR/hPXR mice). Investigations were also performed in cultured male C57BL/6J and CD-1 mouse, male Sprague-Dawley rat and male and female human hepatocytes. The treatment of WT and hCAR/hPXR mice with 186-984 ppm NaPB in the diet for 7 days resulted in increased relative liver weight, hypertrophy and induction of cytochrome P450 (CYP) enzyme activities. Treatment with NaPB also produced dose-dependent increases in hepatocyte replicative DNA synthesis (RDS), with the effect being more marked in WT than in hCAR/hPXR mice. While the treatment of cultured C57BL/6J and CD-1 mouse, Sprague-Dawley rat and human hepatocytes with 100 and/or 1000 μM NaPB for 4 days induced CYP enzyme activities, increased RDS was only observed in mouse and rat hepatocytes. However, as a positive control, epidermal growth factor increased RDS in hepatocytes from all three species. In summary, although human hepatocytes are refractory to the mitogenic effects of NaPB, treatment with NaPB induced RDS in vivo in hCAR/hPXR mice, which is presumably due to the human CAR and PXR receptors operating in a mouse hepatocyte regulatory environment. As the response of the hCAR/hPXR mouse to the CAR activator NaPB differs markedly from that of human hepatocytes, the hCAR/hPXR mouse is thus not a suitable animal model for studies on the hepatic effects of nongenotoxic rodent CAR activators.
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Affiliation(s)
- Corinne Haines
- Concept Life Sciences (formerly CXR Biosciences Ltd.), 2, James Lindsay Place, Dundee Technopole, Dundee, DD1 5JJ, United Kingdom
| | - Barbara M Elcombe
- Concept Life Sciences (formerly CXR Biosciences Ltd.), 2, James Lindsay Place, Dundee Technopole, Dundee, DD1 5JJ, United Kingdom
| | - Lynsey R Chatham
- Concept Life Sciences (formerly CXR Biosciences Ltd.), 2, James Lindsay Place, Dundee Technopole, Dundee, DD1 5JJ, United Kingdom
| | - Audrey Vardy
- Concept Life Sciences (formerly CXR Biosciences Ltd.), 2, James Lindsay Place, Dundee Technopole, Dundee, DD1 5JJ, United Kingdom.
| | - Larry G Higgins
- Concept Life Sciences (formerly CXR Biosciences Ltd.), 2, James Lindsay Place, Dundee Technopole, Dundee, DD1 5JJ, United Kingdom
| | - Clifford R Elcombe
- Concept Life Sciences (formerly CXR Biosciences Ltd.), 2, James Lindsay Place, Dundee Technopole, Dundee, DD1 5JJ, United Kingdom
| | - Brian G Lake
- Concept Life Sciences (formerly CXR Biosciences Ltd.), 2, James Lindsay Place, Dundee Technopole, Dundee, DD1 5JJ, United Kingdom; Centre for Toxicology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, GU2 7XH, United Kingdom
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Thomson JP, Ottaviano R, Buesen R, Moggs JG, Schwarz M, Meehan RR. Defining baseline epigenetic landscapes in the rat liver. Epigenomics 2017; 9:1503-1527. [PMID: 29130343 PMCID: PMC5957268 DOI: 10.2217/epi-2017-0029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Aim Characterization of the hepatic epigenome following exposure to chemicals and therapeutic drugs provides novel insights into toxicological and pharmacological mechanisms, however appreciation of genome-wide inter- and intra-strain baseline epigenetic variation, particularly in under-characterized species such as the rat is limited. Material & methods To enhance the utility of epigenomic endpoints safety assessment, we map both DNA modifications (5-methyl-cytosine and 5-hydroxymethyl-cytosine) and enhancer related chromatin marks (H3K4me1 and H3K27ac) across multiple male and female rat livers for two important outbred laboratory rat strains (Sprague–Dawley and Wistar). Results & conclusion Integration of DNA modification, enhancer chromatin marks and gene expression profiles reveals clear gender-specific chromatin states at genes which exhibit gender-specific transcription. Taken together this work provides a valuable baseline liver epigenome resource for rat strains that are commonly used in chemical and pharmaceutical safety assessment.
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Affiliation(s)
- John P Thomson
- MRC Human Genetics Unit, Genome Regulation, Institute of Genetics & Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, UK
| | - Raffaele Ottaviano
- MRC Human Genetics Unit, Genome Regulation, Institute of Genetics & Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, UK
| | - Roland Buesen
- BASF SE, Experimental Toxicology & Ecology, 67056 Ludwigshafen, Germany
| | - Jonathan G Moggs
- Preclinical Safety, Translational Medicine, Novartis Institutes for BioMedical Research, CH-4057 Basel, Switzerland
| | - Michael Schwarz
- Department of Toxicology, Institute of Experimental & Clinical Pharmacology & Toxicology, University of Tübingen, 72074 Tübingen, Germany
| | - Richard R Meehan
- MRC Human Genetics Unit, Genome Regulation, Institute of Genetics & Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, UK
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Ohara A, Takahashi Y, Kondo M, Okuda Y, Takeda S, Kushida M, Kobayashi K, Sumida K, Yamada T. Candidate genes responsible for early key events of phenobarbital-promoted mouse hepatocellular tumorigenesis based on differentiation of regulating genes between wild type mice and humanized chimeric mice. Toxicol Res (Camb) 2017; 6:795-813. [PMID: 30090543 PMCID: PMC6062386 DOI: 10.1039/c7tx00163k] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 08/23/2017] [Indexed: 12/12/2022] Open
Abstract
Phenobarbital (PB) is a nongenotoxic hepatocellular carcinogen in rodents. PB induces hepatocellular tumors by activating the constitutive androstane receptor (CAR). Some previous research has suggested the possible involvement of epigenetic regulation in PB-promoted hepatocellular tumorigenesis, but the details of its molecular mechanism are not fully understood. In the present study, comprehensive analyses of DNA methylation, hydroxymethylation and gene expression using microarrays were performed in mouse hepatocellular adenomas induced by a single 90 mg kg-1 intraperitoneal injection dose of diethylnitrosamine (DEN) followed by 500 ppm PB in the diet for 27 weeks. DNA modification and expression of hundreds of genes are coordinately altered in PB-induced mouse hepatocellular adenomas. Of these, gene network analysis showed alterations of CAR signaling and tumor development-related genes. Pathway enrichment analysis revealed that differentially methylated or hydroxymethylated genes belong mainly to pathways involved in development, immune response and cancer cells in contrast to differentially expressed genes belonging primarily to the cell cycle. Furthermore, overlap was evaluated between the genes with altered expression levels with 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) alterations in mouse hepatocellular adenoma induced by DEN/PB and the genes with altered expression levels in the liver of CD-1 mice or humanized chimeric mice treated with PB for 7 days. With the integration of transcriptomic and epigenetic approaches, we detected candidate genes responsible for early key events of PB-promoted mouse hepatocellular tumorigenesis. Interestingly, these genes did not overlap with genes altered by the PB treatment of humanized chimeric mice, thus suggesting a species difference between the effects of PB in mouse and human hepatocytes.
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Affiliation(s)
- Ayako Ohara
- Environmental Health Science Laboratory , Sumitomo Chemical Co. , Ltd. , 1-98 , 3-Chome , Kasugade-Naka , Konohana-ku , Osaka 554-8558 , Japan . ; ; Tel: +81-66466-5322
| | - Yasuhiko Takahashi
- Environmental Health Science Laboratory , Sumitomo Chemical Co. , Ltd. , 1-98 , 3-Chome , Kasugade-Naka , Konohana-ku , Osaka 554-8558 , Japan . ; ; Tel: +81-66466-5322
| | - Miwa Kondo
- Environmental Health Science Laboratory , Sumitomo Chemical Co. , Ltd. , 1-98 , 3-Chome , Kasugade-Naka , Konohana-ku , Osaka 554-8558 , Japan . ; ; Tel: +81-66466-5322
| | - Yu Okuda
- Environmental Health Science Laboratory , Sumitomo Chemical Co. , Ltd. , 1-98 , 3-Chome , Kasugade-Naka , Konohana-ku , Osaka 554-8558 , Japan . ; ; Tel: +81-66466-5322
| | - Shuji Takeda
- Environmental Health Science Laboratory , Sumitomo Chemical Co. , Ltd. , 1-98 , 3-Chome , Kasugade-Naka , Konohana-ku , Osaka 554-8558 , Japan . ; ; Tel: +81-66466-5322
| | - Masahiko Kushida
- Environmental Health Science Laboratory , Sumitomo Chemical Co. , Ltd. , 1-98 , 3-Chome , Kasugade-Naka , Konohana-ku , Osaka 554-8558 , Japan . ; ; Tel: +81-66466-5322
| | - Kentaro Kobayashi
- Environmental Health Science Laboratory , Sumitomo Chemical Co. , Ltd. , 1-98 , 3-Chome , Kasugade-Naka , Konohana-ku , Osaka 554-8558 , Japan . ; ; Tel: +81-66466-5322
| | - Kayo Sumida
- Environmental Health Science Laboratory , Sumitomo Chemical Co. , Ltd. , 1-98 , 3-Chome , Kasugade-Naka , Konohana-ku , Osaka 554-8558 , Japan . ; ; Tel: +81-66466-5322
| | - Tomoya Yamada
- Environmental Health Science Laboratory , Sumitomo Chemical Co. , Ltd. , 1-98 , 3-Chome , Kasugade-Naka , Konohana-ku , Osaka 554-8558 , Japan . ; ; Tel: +81-66466-5322
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36
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Forbes KP, Kouranova E, Tinker D, Janowski K, Cortner D, McCoy A, Cui X. Creation and Preliminary Characterization of Pregnane X Receptor and Constitutive Androstane Receptor Knockout Rats. Drug Metab Dispos 2017; 45:1068-1076. [DOI: 10.1124/dmd.117.075788] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 07/13/2017] [Indexed: 02/01/2023] Open
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Wang X, Zheng L, Wu J, Tang B, Zhang M, Zhu D, Lin X. Constitutive androstane receptor activation promotes bilirubin clearance in a murine model of alcoholic liver disease. Mol Med Rep 2017; 15:3459-3466. [PMID: 28393244 PMCID: PMC5436297 DOI: 10.3892/mmr.2017.6435] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 11/29/2016] [Indexed: 12/20/2022] Open
Abstract
Increased plasma levels of bilirubin have been reported in rat models and patients with alcoholic liver disease (ALD). The constitutive androstane receptor (CAR) is a known xenobiotic receptor, which induces the detoxification and transport of bilirubin. In the present study, the bilirubin transport regulatory mechanisms, and the role of CAR activation in hepatic and extrahepatic bilirubin clearance were investigated in a murine model of ALD. The mice were fed a Lieber-DeCarli ethanol diet or an isocaloric control diet for 4 weeks, followed by the administration of CAR agonists, 1,4-bis-[2-(3,5-dichlorpyridyloxy)]benzene (TCPOBOP) and phenobarbital (PB), and their vehicles to examine the effect of the pharmacological activation of CAR on serum levels of bilirubin and on the bilirubin clearance pathway in ALD by serological survey, western blotting and reverse transcription-quantitative polymerase chain reaction. The results showed that chronic ethanol ingestion impaired the nuclear translocation of CAR, which was accompanied by elevated serum levels of bilirubin, suppression of the expression of hepatic and renal organic anion transporting polypeptide (OATP) 1A1 and hepatic multidrug resistance-associated protein 2 (MRP2), and induction of the expression of UDP-glucuronosyltransferase (UGT) 1A1. The activation of CAR by TCPOBOP and PB resulted in downregulation of the serum levels of bilirubin followed by selective upregulation of the expression levels of OATP1A1, OATP1A4, UGT1A1 and MRP2 in ALD. These results revealed the bilirubin transport regulatory mechanisms and highlighted the importance of CAR in modulating the bilirubin clearance pathway in the ALD mouse model.
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Affiliation(s)
- Xiuyan Wang
- Department of Gastroenterology, Wenzhou People's Hospital, Wenzhou, Zhejiang 325000, P.R. China
| | - Liyu Zheng
- Department of Gastroenterology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Jinming Wu
- Department of Gastroenterology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Binbin Tang
- Department of Gastroenterology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Mengqin Zhang
- Department of Gastroenterology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Debin Zhu
- Department of Gastroenterology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Xianfan Lin
- Department of Gastroenterology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
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38
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Terranova R, Vitobello A, Del Rio Espinola A, Wolf CR, Schwarz M, Thomson J, Meehan R, Moggs J. Progress in identifying epigenetic mechanisms of xenobiotic-induced non-genotoxic carcinogenesis. CURRENT OPINION IN TOXICOLOGY 2017. [DOI: 10.1016/j.cotox.2017.06.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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39
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Kumar R, Mota LC, Litoff EJ, Rooney JP, Boswell WT, Courter E, Henderson CM, Hernandez JP, Corton JC, Moore DD, Baldwin WS. Compensatory changes in CYP expression in three different toxicology mouse models: CAR-null, Cyp3a-null, and Cyp2b9/10/13-null mice. PLoS One 2017; 12:e0174355. [PMID: 28350814 PMCID: PMC5370058 DOI: 10.1371/journal.pone.0174355] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 03/07/2017] [Indexed: 12/12/2022] Open
Abstract
Targeted mutant models are common in mechanistic toxicology experiments investigating the absorption, metabolism, distribution, or elimination (ADME) of chemicals from individuals. Key models include those for xenosensing transcription factors and cytochrome P450s (CYP). Here we investigated changes in transcript levels, protein expression, and steroid hydroxylation of several xenobiotic detoxifying CYPs in constitutive androstane receptor (CAR)-null and two CYP-null mouse models that have subfamily members regulated by CAR; the Cyp3a-null and a newly described Cyp2b9/10/13-null mouse model. Compensatory changes in CYP expression that occur in these models may also occur in polymorphic humans, or may complicate interpretation of ADME studies performed using these models. The loss of CAR causes significant changes in several CYPs probably due to loss of CAR-mediated constitutive regulation of these CYPs. Expression and activity changes include significant repression of Cyp2a and Cyp2b members with corresponding drops in 6α- and 16β-testosterone hydroxylase activity. Further, the ratio of 6α-/15α-hydroxylase activity, a biomarker of sexual dimorphism in the liver, indicates masculinization of female CAR-null mice, suggesting a role for CAR in the regulation of sexually dimorphic liver CYP profiles. The loss of Cyp3a causes fewer changes than CAR. Nevertheless, there are compensatory changes including gender-specific increases in Cyp2a and Cyp2b. Cyp2a and Cyp2b were down-regulated in CAR-null mice, suggesting activation of CAR and potentially PXR following loss of the Cyp3a members. However, the loss of Cyp2b causes few changes in hepatic CYP transcript levels and almost no significant compensatory changes in protein expression or activity with the possible exception of 6α-hydroxylase activity. This lack of a compensatory response in the Cyp2b9/10/13-null mice is probably due to low CYP2B hepatic expression, especially in male mice. Overall, compensatory and regulatory CYP changes followed the order CAR-null > Cyp3a-null > Cyp2b-null mice.
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Affiliation(s)
- Ramiya Kumar
- Biological Sciences, Clemson University, Clemson, SC, United States of America
| | - Linda C. Mota
- Environmental Toxicology, Clemson University, Pendleton, SC, United States of America
| | - Elizabeth J. Litoff
- Biological Sciences, Clemson University, Clemson, SC, United States of America
| | - John P. Rooney
- NHEERL, US-EPA, Research Triangle Park, NC, United States of America
| | - W. Tyler Boswell
- Biological Sciences, Clemson University, Clemson, SC, United States of America
| | - Elliott Courter
- Biological Sciences, Clemson University, Clemson, SC, United States of America
| | | | - Juan P. Hernandez
- Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, United States of America
| | | | - David D. Moore
- Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, United States of America
| | - William S. Baldwin
- Biological Sciences, Clemson University, Clemson, SC, United States of America
- Environmental Toxicology, Clemson University, Pendleton, SC, United States of America
- * E-mail:
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40
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Hepatotoxic effects of cyproconazole and prochloraz in wild-type and hCAR/hPXR mice. Arch Toxicol 2017; 91:2895-2907. [DOI: 10.1007/s00204-016-1925-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 12/20/2016] [Indexed: 12/22/2022]
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41
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Okuda Y, Kushida M, Kikumoto H, Nakamura Y, Higuchi H, Kawamura S, Cohen SM, Lake BG, Yamada T. Evaluation of the human relevance of the constitutive androstane receptor-mediated mode of action for rat hepatocellular tumor formation by the synthetic pyrethroid momfluorothrin. J Toxicol Sci 2017; 42:773-788. [DOI: 10.2131/jts.42.773] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Yu Okuda
- Environmental Health Science Laboratory, Sumitomo Chemical Company, Ltd
- Graduate School of Environmental and Life Science, Okayama University
| | - Masahiko Kushida
- Environmental Health Science Laboratory, Sumitomo Chemical Company, Ltd
| | - Hiroko Kikumoto
- Environmental Health Science Laboratory, Sumitomo Chemical Company, Ltd
| | | | - Hashihiro Higuchi
- Environmental Health Science Laboratory, Sumitomo Chemical Company, Ltd
| | - Satoshi Kawamura
- Environmental Health Science Laboratory, Sumitomo Chemical Company, Ltd
| | - Samuel M. Cohen
- Department of Pathology and Microbiology, University of Nebraska Medical Canter, USA
| | - Brian G. Lake
- Centre for Toxicology, Faculty of Health and Medical Sciences, University of Surrey, United Kingdom
| | - Tomoya Yamada
- Environmental Health Science Laboratory, Sumitomo Chemical Company, Ltd
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42
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Soldatow V, Peffer RC, Trask OJ, Cowie DE, Andersen ME, LeCluyse E, Deisenroth C. Development of an in vitro high content imaging assay for quantitative assessment of CAR-dependent mouse, rat, and human primary hepatocyte proliferation. Toxicol In Vitro 2016; 36:224-237. [PMID: 27530964 DOI: 10.1016/j.tiv.2016.08.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 08/09/2016] [Accepted: 08/11/2016] [Indexed: 02/08/2023]
Abstract
Rodent liver tumors promoted by constitutive androstane receptor (CAR) activation are known to be mediated by key events that include CAR-dependent gene expression and hepatocellular proliferation. Here, an in vitro high content imaging based assay was developed for quantitative assessment of nascent DNA synthesis in primary hepatocyte cultures from mouse, rat, and human species. Detection of DNA synthesis was performed using direct DNA labeling with the nucleoside analog 5-ethynyl-2'-deoxyuridine (EdU). The assay was multiplexed to enable direct quantitation of DNA synthesis, cytotoxicity, and cell count endpoints. An optimized defined medium cocktail was developed to sensitize hepatocytes to cell cycle progression. The baseline EdU response to defined medium was greatest for mouse, followed by rat, and then human. Hepatocytes from all three species demonstrated CAR activation in response to the CAR agonists TCPOBOP, CITCO, and phenobarbital based on increased gene expression for Cyp2b isoforms. When evaluated for a proliferation phenotype, TCPOBOP and CITCO exhibited significant dose-dependent increases in frequency of EdU labeling in mouse and rat hepatocytes that was not observed in hepatocytes from three human donors. The observed species differences are consistent with CAR activators inducing a proliferative response in rodents, a key event in the liver tumor mode of action that is not observed in humans.
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Affiliation(s)
- Valerie Soldatow
- The Hamner Institutes for Health Sciences, Institute for Chemical Safety Sciences, 6 Davis Drive, PO Box 12137, Research Triangle Park, NC 27709, USA
| | - Richard C Peffer
- Syngenta Crop Protection, LLC, P.O. Box 18300, 410 Swing Road, Greensboro, NC 27419-8300, USA
| | - O Joseph Trask
- The Hamner Institutes for Health Sciences, Institute for Chemical Safety Sciences, 6 Davis Drive, PO Box 12137, Research Triangle Park, NC 27709, USA
| | - David E Cowie
- Syngenta Crop Protection, LLC, P.O. Box 18300, 410 Swing Road, Greensboro, NC 27419-8300, USA
| | - Melvin E Andersen
- The Hamner Institutes for Health Sciences, Institute for Chemical Safety Sciences, 6 Davis Drive, PO Box 12137, Research Triangle Park, NC 27709, USA; ScitoVation, LLC, 6 Davis Drive, PO Box 110566, Research Triangle Park, NC 27709, USA
| | - Edward LeCluyse
- The Hamner Institutes for Health Sciences, Institute for Chemical Safety Sciences, 6 Davis Drive, PO Box 12137, Research Triangle Park, NC 27709, USA
| | - Chad Deisenroth
- The Hamner Institutes for Health Sciences, Institute for Chemical Safety Sciences, 6 Davis Drive, PO Box 12137, Research Triangle Park, NC 27709, USA; ScitoVation, LLC, 6 Davis Drive, PO Box 110566, Research Triangle Park, NC 27709, USA.
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43
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Derisking Drug-Induced Carcinogenicity for Novel Therapeutics. Trends Cancer 2016; 2:398-408. [DOI: 10.1016/j.trecan.2016.07.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 07/07/2016] [Accepted: 07/08/2016] [Indexed: 12/21/2022]
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Pondugula SR, Pavek P, Mani S. Pregnane X Receptor and Cancer: Context-Specificity is Key. NUCLEAR RECEPTOR RESEARCH 2016; 3. [PMID: 27617265 DOI: 10.11131/2016/101198] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Pregnane X receptor (PXR) is an adopted orphan nuclear receptor that is activated by a wide-range of endobiotics and xenobiotics, including chemotherapy drugs. PXR plays a major role in the metabolism and clearance of xenobiotics and endobiotics in liver and intestine via induction of drug-metabolizing enzymes and drug-transporting proteins. However, PXR is expressed in several cancer tissues and the accumulating evidence strongly points to the differential role of PXR in cancer growth and progression as well as in chemotherapy outcome. In cancer cells, besides regulating the gene expression of enzymes and proteins involved in drug metabolism and transport, PXR also regulates other genes involved in proliferation, metastasis, apoptosis, anti-apoptosis, inflammation, and oxidative stress. In this review, we focus on the differential role of PXR in a variety of cancers, including prostate, breast, ovarian, endometrial, and colon. We also discuss the future directions to further understand the differential role of PXR in cancer, and conclude with the need to identify novel selective PXR modulators to target PXR in PXR-expressing cancers.
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Affiliation(s)
- Satyanarayana R Pondugula
- Department of Anatomy, Physiology and Pharmacology, Auburn University, Auburn, AL 36849, USA; Auburn University Research Initiative in Cancer, Auburn University, Auburn, AL 36849, USA
| | - Petr Pavek
- Faculty of Pharmacy in Hradec Králové, Charles University in Prague, Heyrovského 1203, Hradec Králové 500 05, Czech Republic, European Union
| | - Sridhar Mani
- Albert Einstein Cancer Center, Albert Einstein College of Medicine, New York, NY 10461, USA
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45
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Menegon S, Columbano A, Giordano S. The Dual Roles of NRF2 in Cancer. Trends Mol Med 2016; 22:578-593. [PMID: 27263465 DOI: 10.1016/j.molmed.2016.05.002] [Citation(s) in RCA: 457] [Impact Index Per Article: 57.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 05/06/2016] [Accepted: 05/09/2016] [Indexed: 12/19/2022]
Abstract
NRF2 has been traditionally considered as a tumor suppressor because its cytoprotective functions are deemed to be the main cellular defense mechanism against exogenous and endogenous insults, including xenobiotics and oxidative stress. However, several recent studies demonstrate that hyperactivation of the NRF2 pathway creates an environment that favors the survival of normal as well as malignant cells, protecting them against oxidative stress, chemotherapeutic agents, and radiotherapy. In a rapidly advancing field, this review summarizes some of the known mechanisms by which NRF2 can exert its oncogenic functions, and describes the current status of NRF2 inhibitors, providing a clear rationale for the consideration of NRF2 as a powerful putative therapeutic target in cancer treatment.
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Affiliation(s)
- Silvia Menegon
- University of Torino, Department of Oncology, Candiolo Cancer Institute-FPO, IRCCS, Strada Provinciale 142, 10060 Candiolo, Torino, Italy.
| | - Amedeo Columbano
- Department of Biomedical Sciences, University of Cagliari, Via Porcell 4, 09124 Cagliari, Italy.
| | - Silvia Giordano
- University of Torino, Department of Oncology, Candiolo Cancer Institute-FPO, IRCCS, Strada Provinciale 142, 10060 Candiolo, Torino, Italy.
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46
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Thomson JP, Ottaviano R, Unterberger EB, Lempiäinen H, Muller A, Terranova R, Illingworth RS, Webb S, Kerr ARW, Lyall MJ, Drake AJ, Wolf CR, Moggs JG, Schwarz M, Meehan RR. Loss of Tet1-Associated 5-Hydroxymethylcytosine Is Concomitant with Aberrant Promoter Hypermethylation in Liver Cancer. Cancer Res 2016; 76:3097-108. [PMID: 27197233 PMCID: PMC5021200 DOI: 10.1158/0008-5472.can-15-1910] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 03/09/2016] [Indexed: 12/17/2022]
Abstract
Aberrant hypermethylation of CpG islands (CGI) in human tumors occurs predominantly at repressed genes in the host tissue, but the preceding events driving this phenomenon are poorly understood. In this study, we temporally tracked epigenetic and transcriptomic perturbations that occur in a mouse model of liver carcinogenesis. Hypermethylated CGI events in the model were predicted by enrichment of the DNA modification 5-hydroxymethylcytosine (5hmC) and the histone H3 modification H3K27me3 at silenced promoters in the host tissue. During cancer progression, selected CGIs underwent hypo-hydroxymethylation prior to hypermethylation, while retaining H3K27me3. In livers from mice deficient in Tet1, a tumor suppressor involved in cytosine demethylation, we observed a similar loss of promoter core 5hmC, suggesting that reduced Tet1 activity at CGI may contribute to epigenetic dysregulation during hepatocarcinogenesis. Consistent with this possibility, mouse liver tumors exhibited reduced Tet1 protein levels. Similar to humans, DNA methylation changes at CGI in mice did not appear to be direct drivers of hepatocellular carcinoma progression, rather, dynamic changes in H3K27me3 promoter deposition correlated strongly with tumor-specific activation and repression of transcription. Overall, our results suggest that loss of promoter-associated 5hmC in liver tumors licenses reprograming of DNA methylation at silent CGI during progression. Cancer Res; 76(10); 3097-108. ©2016 AACR.
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Affiliation(s)
- John P Thomson
- MRC Human Genetics Unit at the Institute of Genetics and Molecular Medicine at the University of Edinburgh, Edinburgh, United Kingdom
| | - Raffaele Ottaviano
- MRC Human Genetics Unit at the Institute of Genetics and Molecular Medicine at the University of Edinburgh, Edinburgh, United Kingdom
| | - Elif B Unterberger
- Department of Toxicology, Institute of Experimental and Clinical Pharmacology and Toxicology, University of Tübingen, Tübingen, Germany
| | - Harri Lempiäinen
- Preclinical Safety, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Arne Muller
- Preclinical Safety, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Remi Terranova
- Preclinical Safety, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Robert S Illingworth
- MRC Human Genetics Unit at the Institute of Genetics and Molecular Medicine at the University of Edinburgh, Edinburgh, United Kingdom
| | - Shaun Webb
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Alastair R W Kerr
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Marcus J Lyall
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
| | - Amanda J Drake
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
| | - C Roland Wolf
- Medical Research Institute, University of Dundee, Ninewells Hospital & Medical School, Dundee, United Kingdom
| | - Jonathan G Moggs
- Preclinical Safety, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Michael Schwarz
- Department of Toxicology, Institute of Experimental and Clinical Pharmacology and Toxicology, University of Tübingen, Tübingen, Germany.
| | - Richard R Meehan
- MRC Human Genetics Unit at the Institute of Genetics and Molecular Medicine at the University of Edinburgh, Edinburgh, United Kingdom.
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Cave MC, Clair HB, Hardesty JE, Falkner KC, Feng W, Clark BJ, Sidey J, Shi H, Aqel BA, McClain CJ, Prough RA. Nuclear receptors and nonalcoholic fatty liver disease. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2016; 1859:1083-1099. [PMID: 26962021 DOI: 10.1016/j.bbagrm.2016.03.002] [Citation(s) in RCA: 196] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 02/29/2016] [Accepted: 03/01/2016] [Indexed: 02/08/2023]
Abstract
Nuclear receptors are transcription factors which sense changing environmental or hormonal signals and effect transcriptional changes to regulate core life functions including growth, development, and reproduction. To support this function, following ligand-activation by xenobiotics, members of subfamily 1 nuclear receptors (NR1s) may heterodimerize with the retinoid X receptor (RXR) to regulate transcription of genes involved in energy and xenobiotic metabolism and inflammation. Several of these receptors including the peroxisome proliferator-activated receptors (PPARs), the pregnane and xenobiotic receptor (PXR), the constitutive androstane receptor (CAR), the liver X receptor (LXR) and the farnesoid X receptor (FXR) are key regulators of the gut:liver:adipose axis and serve to coordinate metabolic responses across organ systems between the fed and fasting states. Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease and may progress to cirrhosis and even hepatocellular carcinoma. NAFLD is associated with inappropriate nuclear receptor function and perturbations along the gut:liver:adipose axis including obesity, increased intestinal permeability with systemic inflammation, abnormal hepatic lipid metabolism, and insulin resistance. Environmental chemicals may compound the problem by directly interacting with nuclear receptors leading to metabolic confusion and the inability to differentiate fed from fasting conditions. This review focuses on the impact of nuclear receptors in the pathogenesis and treatment of NAFLD. Clinical trials including PIVENS and FLINT demonstrate that nuclear receptor targeted therapies may lead to the paradoxical dissociation of steatosis, inflammation, fibrosis, insulin resistance, dyslipidemia and obesity. Novel strategies currently under development (including tissue-specific ligands and dual receptor agonists) may be required to separate the beneficial effects of nuclear receptor activation from unwanted metabolic side effects. The impact of nuclear receptor crosstalk in NAFLD is likely to be profound, but requires further elucidation. This article is part of a Special Issue entitled: Xenobiotic nuclear receptors: New Tricks for An Old Dog, edited by Dr. Wen Xie.
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Affiliation(s)
- Matthew C Cave
- Department of Medicine, Division of Gastroenterology, Hepatology and Nutrition, University of Louisville School of Medicine, Louisville, KY 40202, USA; Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY 40202, USA; Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY 40202, USA; The Robley Rex Veterans Affairs Medical Center, Louisville, KY 40206, USA; The KentuckyOne Health Jewish Hospital Liver Transplant Program, Louisville, KY 40202, USA.
| | - Heather B Clair
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - Josiah E Hardesty
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - K Cameron Falkner
- Department of Medicine, Division of Gastroenterology, Hepatology and Nutrition, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - Wenke Feng
- Department of Medicine, Division of Gastroenterology, Hepatology and Nutrition, University of Louisville School of Medicine, Louisville, KY 40202, USA; Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - Barbara J Clark
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - Jennifer Sidey
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - Hongxue Shi
- Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - Bashar A Aqel
- Department of Medicine, Division of Gastroenterology and Hepatology, Mayo Clinic College of Medicine, Scottsdale, AZ 85054, USA
| | - Craig J McClain
- Department of Medicine, Division of Gastroenterology, Hepatology and Nutrition, University of Louisville School of Medicine, Louisville, KY 40202, USA; Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY 40202, USA; The Robley Rex Veterans Affairs Medical Center, Louisville, KY 40206, USA; The KentuckyOne Health Jewish Hospital Liver Transplant Program, Louisville, KY 40202, USA
| | - Russell A Prough
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY 40202, USA
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Scheer N, Wilson ID. A comparison between genetically humanized and chimeric liver humanized mouse models for studies in drug metabolism and toxicity. Drug Discov Today 2015; 21:250-63. [PMID: 26360054 DOI: 10.1016/j.drudis.2015.09.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Revised: 08/07/2015] [Accepted: 09/01/2015] [Indexed: 12/12/2022]
Abstract
Mice that have been genetically humanized for proteins involved in drug metabolism and toxicity and mice engrafted with human hepatocytes are emerging and promising in vivo models for an improved prediction of the pharmacokinetic, drug-drug interaction and safety characteristics of compounds in humans. The specific advantages and disadvantages of these models should be carefully considered when using them for studies in drug discovery and development. Here, an overview on the corresponding genetically humanized and chimeric liver humanized mouse models described to date is provided and illustrated with examples of their utility in drug metabolism and toxicity studies. We compare the strength and weaknesses of the two different approaches, give guidance for the selection of the appropriate model for various applications and discuss future trends and perspectives.
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Affiliation(s)
| | - Ian D Wilson
- Imperial College London, South Kensington, London SW7 2AZ, UK.
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Zhang XJ, Shi Z, Lyv JX, He X, Englert NA, Zhang SY. Pyrene is a Novel Constitutive Androstane Receptor (CAR) Activator and Causes Hepatotoxicity by CAR. Toxicol Sci 2015; 147:436-45. [PMID: 26160115 DOI: 10.1093/toxsci/kfv142] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are a class of ubiquitous persistent environmental pollutants which are primarily formed from the incomplete combustion of organic materials. Many potential sources of human exposure to PAHs exist, including daily exposures from the ambient environment or occupational settings. PAHs have been found to cause harmful effects on human health. Here, we evaluated the adverse effects of pyrene, a common PAH, on the liver. The present study demonstrates that pyrene is able to activate mouse constitutive androstane receptor (CAR). CAR protein, as measured by Western blot analysis, was observed to translocate into the nucleus from the cytoplasm in mouse liver after exposure to pyrene. Utilizing CAR null mice, we identified that CAR mediates pyrene-induced hepatotoxicity. Increased relative liver weight, hepatocellular hypertrophy, and elevated serum alanine aminotransferase levels were found in wild-type but not CAR null mice after orally administered pyrene. We further show that pyrene induced the expression of mouse liver metabolism enzymes including CYP2B10, CYP3A11, GSTm1, GSTm3, and SULT1A1, and caused hepatic glutathione depletion in wild-type but not CAR null mice. Moreover, by luciferase reporter assay and quantitative real-time PCR analysis, pyrene was found to be a potential inducer of CYP2B6 expression via activation of human CAR in HepG2 cells and human primary hepatocytes. Our observations suggest that pyrene is a novel CAR activator and that CAR is essential for mediating pyrene-induced liver injury.
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Affiliation(s)
- Xiao-Jie Zhang
- *Department of Preventive Medicine, School of Environmental Science and Public Health, Wenzhou Medical University, Wenzhou, Zhejiang 325035, People's Republic of China and
| | - Zhe Shi
- *Department of Preventive Medicine, School of Environmental Science and Public Health, Wenzhou Medical University, Wenzhou, Zhejiang 325035, People's Republic of China and
| | - Jing-Xi Lyv
- *Department of Preventive Medicine, School of Environmental Science and Public Health, Wenzhou Medical University, Wenzhou, Zhejiang 325035, People's Republic of China and
| | - Xuyan He
- *Department of Preventive Medicine, School of Environmental Science and Public Health, Wenzhou Medical University, Wenzhou, Zhejiang 325035, People's Republic of China and
| | - Neal A Englert
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - Shu-Yun Zhang
- *Department of Preventive Medicine, School of Environmental Science and Public Health, Wenzhou Medical University, Wenzhou, Zhejiang 325035, People's Republic of China and
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Cherian MT, Chai SC, Chen T. Small-molecule modulators of the constitutive androstane receptor. Expert Opin Drug Metab Toxicol 2015; 11:1099-114. [PMID: 25979168 DOI: 10.1517/17425255.2015.1043887] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
INTRODUCTION The constitutive androstane receptor (CAR) induces drug-metabolizing enzymes for xenobiotic metabolism. AREAS COVERED This review covers recent advances in elucidating the biological functions of CAR and its modulation by a growing number of agonists and inhibitors. EXPERT OPINION Extrapolation of animal CAR function to that of humans should be carefully scrutinized, particularly when rodents are used in evaluating the metabolic profile and carcinogenic properties of clinical drugs and environmental chemicals. Continuous efforts are needed to discover novel CAR inhibitors, with extensive understanding of their inhibitory mechanism, species selectivity, and discriminating power against other xenobiotic sensors.
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Affiliation(s)
- Milu T Cherian
- Postdoctoral fellow, St. Jude Children's Research Hospital, Department of Chemical Biology and Therapeutics , 262 Danny Thomas Place, Memphis, TN 38105 , USA
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