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Lu M, Li M, Luo T, Li Y, Wang M, Xue H, Zhang M, Chen Q. Beta-naphthoflavone increases the differentiation of osteoblasts and suppresses adipogenesis in human adipose derived stem cells involving STAT3 pathway. Mol Cell Toxicol 2022. [DOI: 10.1007/s13273-022-00283-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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2
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Lin CH, Chou CC, Lee YH, Hung CC. Curcumin Facilitates Aryl Hydrocarbon Receptor Activation to Ameliorate Inflammatory Astrogliosis. Molecules 2022; 27:2507. [PMID: 35458704 PMCID: PMC9024799 DOI: 10.3390/molecules27082507] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 04/08/2022] [Accepted: 04/11/2022] [Indexed: 12/12/2022] Open
Abstract
Curcumin is an anti-inflammatory and neuroprotective compound in turmeric. It is a potential ligand of the aryl hydrocarbon receptor (AhR) that mediates anti-inflammatory signaling. However, the AhR-mediated anti-inflammatory effect of curcumin within the brain remains unclear. We investigated the role of AhR on the curcumin effect in inflammatory astrogliosis. Curcumin attenuated lipopolysaccharide (LPS)-induced proinflammatory IL-6 and TNF-α gene expression in primary cultured rat astrocytes. When AhR was knocked down, LPS-induced IL-6 and TNF-α were increased and curcumin-decreased activation of the inflammation mediator NF-κB p65 by LPS was abolished. Although LPS increased AhR and its target gene CYP1B1, curcumin further enhanced LPS-induced CYP1B1 and indoleamine 2,3-dioxygenase (IDO), which metabolizes tryptophan to AhR ligands kynurenine (KYN) and kynurenic acid (KYNA). Potential interactions between curcumin and human AhR analyzed by molecular modeling of ligand-receptor docking. We identified a new ligand binding site on AhR different from the classical 2,3,7,8-tetrachlorodibenzo-p-dioxin site. Curcumin docked onto the classical binding site, whereas KYN and KYNA occupied the novel one. Moreover, curcumin and KYNA collaboratively bound onto AhR during molecular docking, potentially resulting in synergistic effects influencing AhR activation. Curcumin may enhance the inflammation-induced IDO/KYN axis and allosterically regulate endogenous ligand binding to AhR, facilitating AhR activation to regulate inflammatory astrogliosis.
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Affiliation(s)
- Chun-Hua Lin
- Department of Nursing, Kang-Ning University, Taipei 11485, Taiwan
- School of Nursing, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
| | - Chia-Cheng Chou
- National Laboratory Animal Center, National Applied Research Laboratories, Taipei 115202, Taiwan;
| | - Yi-Hsuan Lee
- Department and Institute of Physiology, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan;
- Brain Research Center, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
| | - Chia-Chi Hung
- Department and Institute of Physiology, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan;
- Brain Research Center, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
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Safe S, Jayaraman A, Chapkin RS. Ah receptor ligands and their impacts on gut resilience: structure-activity effects. Crit Rev Toxicol 2020; 50:463-473. [PMID: 32597352 DOI: 10.1080/10408444.2020.1773759] [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: 02/08/2023]
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD, dioxin) and structurally related halogenated aromatics modulate gene expression and induce biochemical and toxic responses that are mediated by initial binding to the aryl hydrocarbon receptor (AhR). The AhR also binds structurally diverse compound including pharmaceuticals, endogenous biochemicals, health-promoting phytochemicals, and microbial metabolites. Many of these AhR ligands do not induce TCDD-like toxic responses and some AhR ligands such as microbial metabolites of tryptophan play a role in maintaining gut health and protecting against intestinal inflammation and cancer. Many AhR ligands exhibit tissue- and response-specific AhR agonist or antagonist activities, and act as selective AhR modulators (SAhRMs) and this SAhRM-like activity has also been observed in AhR-ligand-mediated effects in the intestine. This review summarizes studies showing that several AhR ligands including phytochemicals and TCDD protect against dextran sodium sulfate-induced intestinal inflammation. In contrast, AhR ligands such as oxazole compounds enhance intestinal inflammation suggesting that AhR-mediated gut health can be enhanced or decreased by selective AhR modulators and this needs to be considered in development of AhR ligands for therapeutic applications in treating intestinal inflammation.
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Affiliation(s)
- Stephen Safe
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX, USA
| | - Arul Jayaraman
- Department of Chemical Engineering, Texas A&M University, College Station, TX, USA
| | - Robert S Chapkin
- Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, TX, USA
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Zhang J, Zong H, Li S, Zhang D, Zhang L, Xia Q. Activation of Aryl Hydrocarbon Receptor Suppresses Invasion of Esophageal Squamous Cell Carcinoma Cell Lines. TUMORI JOURNAL 2018; 98:152-7. [DOI: 10.1177/030089161209800121] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Aims and Background Esophageal cancer is the eighth most common malignancy and sixth leading cause of cancer deaths in the world. Recent studies have shown the potential role of the aryl hydrocarbon receptor (AhR) in tumor development; however, little is known about its role in esophageal squamous cell carcinoma. In the present study, we evaluated AhR expression in esophageal tumor tissues as well as cell lines and investigated the effects of AhR activation by its agonist BNF on esophageal squamous cell carcinoma invasion using Eca109 and TE-13 cells as a model. Methods Western blotting was performed to detect the AhR and CYP1A1 protein expression. Transwell migration assays were carried out to study the effects of BNF on esophageal squamous cell carcinoma cell invasion. AhR-specific siRNA was used to knock down the expression of AhR protein. Results Our results showed that AhR was highly expressed in esophageal squamous cell carcinoma tissues and cell lines when compared with its expression in normal tissue. AhR siRNA robustly decreased AhR protein expression in both Eca109 and TE-13 cells. BNF significantly inhibited invasion of human esophageal squamous cell carcinoma cells via activation of AhR. Conclusions The obtained results provide critical information on the roles of BNF in mediating esophageal squamous cell carcinoma invasion. This information could be useful for future therapeutic intervention in this lethal human disease.
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Affiliation(s)
- Jianhao Zhang
- Interventional Oncology Center, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan
| | - Hong Zong
- Department of Oncology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan
| | - Shenglei Li
- Department of Pathology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan
| | - Dandan Zhang
- Department of Pathology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan
| | - Lei Zhang
- Department of Oncology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan
| | - Qingxin Xia
- Department of Pathology, Henan Tumor Hospital, Zhengzhou, Henan, PR China. Jianhao Zhang and Hong Zong contributed equally to this work
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Asai Y, Sakakibara Y, Nadai M, Katoh M. Effect of carbamazepine on expression of UDP-glucuronosyltransferase 1A6 and 1A7 in rat brain. Drug Metab Pharmacokinet 2017; 32:286-292. [DOI: 10.1016/j.dmpk.2017.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 09/05/2017] [Accepted: 09/08/2017] [Indexed: 12/12/2022]
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6
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Pierucci F, Frati A, Squecco R, Lenci E, Vicenti C, Slavik J, Francini F, Machala M, Meacci E. Non-dioxin-like organic toxicant PCB153 modulates sphingolipid metabolism in liver progenitor cells: its role in Cx43-formed gap junction impairment. Arch Toxicol 2016; 91:749-760. [PMID: 27318803 DOI: 10.1007/s00204-016-1750-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 06/08/2016] [Indexed: 12/13/2022]
Abstract
The non-dioxin-like environmental toxicant 2,2',4,4',5,5'-hexachlorobiphenyl (PCB153), member of a group of persistent organic pollutants wide-spread throughout the environment, reduces gap junction intercellular communication (GJIC), an event possibly associated with tumor promotion. Since very few studies have investigated the signaling effectors and mode(s) of action of PCB153, and it is known that the gap junction (GJ) protein Cx43 can be regulated by the bioactive sphingolipid (SL) sphingosine 1-phosphate (S1P), this in vitro study mainly addresses whether SL metabolism is affected by PCB153 in rat liver epithelial WB-F344 cells. PCB153 treatment obtained significant changes in the S1P/ceramide (Cer) ratio, known to be crucial in determining cell fate. In particular, an increase in S1P at 30 min and a decrease of the bioactive lipid at 3 h were observed, whereas Cer level increased at 1 h and 24 h. Notably, a time-dependent modulation of sphingosine kinase (SphK), the enzyme responsible for S1P synthesis, and of its regulators, ERK1/2 and protein phosphatase PP2A, supports the involvement of these signaling effectors in PCB153 toxicity. Electrophysiological analyses, furthermore, indicated that the lipophilic environmental toxicant significantly reduced GJ biophysical properties, affecting both voltage-dependent (such as those formed by Cx43 and/or Cx32) and voltage-independent channels, thereby demonstrating that PCB153 may act differently on GJs formed by distinct Cx isoforms. SphK down-regulation alone induced GJIC impairment, and, when combined with PCB153, the acute effect on GJ suppression was additive. Moreover, after enzyme-specific gene silencing, the SphK1 isoform appears to be responsible for down-regulating Cx43 expression, while being the target of PCB153 at short-term exposure. In conclusion, we provide the first evidence of novel effectors in PCB153 toxic action in rat liver stem-like cells, leading us to consider SLs as potential markers for preventing GJIC deregulation and, thus, the tumorigenic action elicited by this environmental toxicant.
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Affiliation(s)
- F Pierucci
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Research Unit of Molecular and Applied Biology, University of Florence, Viale GB Morgagni 50, 50134, Florence, Italy
| | - A Frati
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Research Unit of Molecular and Applied Biology, University of Florence, Viale GB Morgagni 50, 50134, Florence, Italy
| | - R Squecco
- Department of Experimental and Clinical Medicine, Section of Physiological Sciences, University of Florence, Viale GB Morgagni 63, 50134, Florence, Italy
| | - E Lenci
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Research Unit of Molecular and Applied Biology, University of Florence, Viale GB Morgagni 50, 50134, Florence, Italy
| | - C Vicenti
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Research Unit of Molecular and Applied Biology, University of Florence, Viale GB Morgagni 50, 50134, Florence, Italy
| | - J Slavik
- Veterinary Research Institute, Hudcova 70, 62100, Brno, Czech Republic
| | - F Francini
- Department of Experimental and Clinical Medicine, Section of Physiological Sciences, University of Florence, Viale GB Morgagni 63, 50134, Florence, Italy
| | - M Machala
- Veterinary Research Institute, Hudcova 70, 62100, Brno, Czech Republic
| | - E Meacci
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", Research Unit of Molecular and Applied Biology, University of Florence, Viale GB Morgagni 50, 50134, Florence, Italy.
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Environmental Ligands of the Aryl Hydrocarbon Receptor and Their Effects in Models of Adult Liver Progenitor Cells. Stem Cells Int 2016; 2016:4326194. [PMID: 27274734 PMCID: PMC4870370 DOI: 10.1155/2016/4326194] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 04/07/2016] [Indexed: 12/20/2022] Open
Abstract
The toxicity of environmental and dietary ligands of the aryl hydrocarbon receptor (AhR) in mature liver parenchymal cells is well appreciated, while considerably less attention has been paid to their impact on cell populations exhibiting phenotypic features of liver progenitor cells. Here, we discuss the results suggesting that the consequences of the AhR activation in the cellular models derived from bipotent liver progenitors could markedly differ from those in hepatocytes. In contact-inhibited liver progenitor cells, the AhR agonists induce a range of effects potentially linked with tumor promotion. They can stimulate cell cycle progression/proliferation and deregulate cell-to-cell communication, which is associated with downregulation of proteins forming gap junctions, adherens junctions, and desmosomes (such as connexin 43, E-cadherin, β-catenin, and plakoglobin), as well as with reduced cell adhesion and inhibition of intercellular communication. At the same time, toxic AhR ligands may affect the activity of the signaling pathways contributing to regulation of liver progenitor cell activation and/or differentiation, such as downregulation of Wnt/β-catenin and TGF-β signaling, or upregulation of transcriptional targets of YAP/TAZ, the effectors of Hippo signaling pathway. These data illustrate the need to better understand the potential role of liver progenitors in the AhR-mediated liver carcinogenesis and tumor promotion.
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Abstract
The pregnane X receptor (PXR) and constitutive androstane receptor (CAR), 2 closely related and liver-enriched members of the nuclear receptor superfamily, and aryl hydrocarbon receptor (AhR), a nonnuclear receptor transcription factor (TF), are major receptors/TFs regulating the expression of genes for the clearance and detoxification of xenobiotics. They are hence defined as "xenobiotic receptors". Recent studies have demonstrated that PXR, CAR and AhR also regulate the expression of key proteins involved in endobiotic responses such as the metabolic homeostasis of lipids, glucose, and bile acid, and inflammatory processes. It is suggested that the functions of PXR, CAR and AhR may be closely implicated in the pathogeneses of metabolic vascular diseases, such as hyperlipidemia, atherogenesis, and hypertension. Therefore, manipulation of the activities of these receptors may provide novel strategies for the treatment of vascular diseases. Here, we review the pathophysiological roles of PXR, CAR and AhR in the vascular system.
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Affiliation(s)
- Lei Xiao
- Cardiovascular Research Center, School of Medicine, Xi'an Jiaotong University
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Procházková J, Kabátková M, Šmerdová L, Pacherník J, Sykorová D, Kohoutek J, Šimečková P, Hrubá E, Kozubík A, Machala M, Vondráček J. Aryl hydrocarbon receptor negatively regulates expression of the plakoglobin gene (jup). Toxicol Sci 2013; 134:258-70. [PMID: 23690540 DOI: 10.1093/toxsci/kft110] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Plakoglobin is an important component of intercellular junctions, including both desmosomes and adherens junctions, which is known as a tumor suppressor. Although mutations in the plakoglobin gene (Jup) and/or changes in its protein levels have been observed in various disease states, including cancer progression or cardiovascular defects, the information about endogenous or exogenous stimuli orchestrating Jup expression is limited. Here we show that the aryl hydrocarbon receptor (AhR) may regulate Jup expression in a cell-specific manner. We observed a significant suppressive effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a model toxic exogenous activator of the AhR signaling, on Jup expression in a variety of experimental models derived from rodent tissues, including contact-inhibited rat liver progenitor cells (where TCDD induces cell proliferation), rat and mouse hepatoma cell models (where TCDD inhibits cell cycle progression), cardiac cells derived from the mouse embryonic stem cells, or cardiomyocytes isolated from neonatal rat hearts. The small interfering RNA (siRNA)-mediated knockdown of AhR confirmed its role in both basal and TCDD-deregulated Jup expression. The analysis of genomic DNA located ~2.5kb upstream of rat Jup gene revealed a presence of evolutionarily conserved AhR binding motifs, which were confirmed upon their cloning into luciferase reporter construct. The siRNA-mediated knockdown of Jup expression affected both proliferation and attachment of liver progenitor cells. The present data indicate that the AhR may contribute to negative regulation of Jup gene expression in rodent cellular models, which may affect cell adherence and proliferation.
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Affiliation(s)
- Jiřina Procházková
- Department of Cytokinetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, 61265 Brno, Czech Republic
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Faust D, Vondráček J, Krčmář P, Šmerdová L, Procházková J, Hrubá E, Hulinková P, Kaina B, Dietrich C, Machala M. AhR-mediated changes in global gene expression in rat liver progenitor cells. Arch Toxicol 2012. [DOI: 10.1007/s00204-012-0979-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Andrysík Z, Procházková J, Kabátková M, Umannová L, Šimečková P, Kohoutek J, Kozubík A, Machala M, Vondráček J. Aryl hydrocarbon receptor-mediated disruption of contact inhibition is associated with connexin43 downregulation and inhibition of gap junctional intercellular communication. Arch Toxicol 2012; 87:491-503. [DOI: 10.1007/s00204-012-0963-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 10/11/2012] [Indexed: 11/29/2022]
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Volkov MS, Bolotina NA, Evteev VA, Koblyakov VA. Ah-receptor-independent stimulation of hepatoma 27 culture cell proliferation by polycyclic aromatic hydrocarbons. BIOCHEMISTRY (MOSCOW) 2012; 77:201-7. [DOI: 10.1134/s0006297912020125] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Elsherbiny ME, Brocks DR. The ability of polycyclic aromatic hydrocarbons to alter physiological factors underlying drug disposition. Drug Metab Rev 2011; 43:457-75. [DOI: 10.3109/03602532.2011.596204] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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14
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Procházková J, Kabátková M, Bryja V, Umannová L, Bernatík O, Kozubík A, Machala M, Vondráček J. The Interplay of the Aryl Hydrocarbon Receptor and β-Catenin Alters Both AhR-Dependent Transcription and Wnt/β-Catenin Signaling in Liver Progenitors. Toxicol Sci 2011; 122:349-60. [DOI: 10.1093/toxsci/kfr129] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
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15
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Abstract
We review the evidence suggesting the involvement of Cadherin 13 (CDH13, T-cadherin, H-cadherin) in various cancers. CDH13 is an atypical member of the cadherin family, devoid of a transmembrane domain and anchored to the exterior surface of the plasma membrane via a glycosylphosphatidylinositol anchor. CDH13 is thought to affect cellular behavior largely through its signaling properties. It is often down-regulated in cancerous cells. CDH13 down-regulation has been associated with poorer prognosis in various carcinomas, such as lung, ovarian, cervical and prostate cancer. CDH13 re-expression in most cancer cell lines inhibits cell proliferation and invasiveness, increases susceptibility to apoptosis, and reduces tumor growth in in vivo models. These properties suggest that CDH13 may represent a possible target for therapy in some cancers. At the same time, CDH13 is up-regulated in blood vessels growing through tumors and promotes tumor neovascularization. In contrast to most cancer cell lines, CDH13 overexpression in endothelial cells promotes their proliferation and migration, and has a pro-survival effect. We also discuss molecular mechanisms that may regulate CDH13 expression and underlie its roles in cancer.
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Affiliation(s)
- Alexandra V Andreeva
- Department of Pharmacology, University of Illinois, College of Medicine, Chicago, IL, USA.
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Procházková J, Kozubík A, Machala M, Vondráček J. Differential effects of indirubin and 2,3,7,8-tetrachlorodibenzo-p-dioxin on the aryl hydrocarbon receptor (AhR) signalling in liver progenitor cells. Toxicology 2010; 279:146-54. [PMID: 20951181 DOI: 10.1016/j.tox.2010.10.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Revised: 09/21/2010] [Accepted: 10/07/2010] [Indexed: 11/29/2022]
Abstract
In the present study, we investigated the effects of potential endogenous ligand indirubin on the aryl hydrocarbon receptor (AhR) signalling, with a focus on the AhR-dependent gene expression and cell cycle progression in rat liver progenitor cells, and compared them with the effects of a model toxic AhR ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The low (picomolar and nanomolar) doses of indirubin, corresponding to expected endogenous levels, induced a transient translocation of AhR to the nucleus, while high (micromolar) doses induced a long-term AhR nuclear translocation, followed by its degradation, similar to the effects of TCDD. Whereas high doses of indirubin recruited AhR/ARNT1 dimer to rat Cyp1a1 promoter, the low doses did not induce its DNA binding, as revealed by the chromatin immunoprecipitation assay. This corresponded with the fact that the micromolar doses of indirubin significantly increased Cyp1a1/1b1 mRNA in a way similar to TCDD, while the low doses of indirubin were only poor inducers of Cyp1a1/1b1 expression. Comparable patterns of expression were observed also for other AhR gene targets, such as Nqo1 and Nrf2. Also, only micromolar doses of indirubin were able to mimic the effects of TCDD on cell cycle and proliferation of liver progenitor cells or hepatoma cells. Nevertheless, indirubin at low concentrations may have unique effects on gene expression in non-tumorigenic cells. Although both TCDD and the high doses of indirubin repressed plakoglobin (Jup) expression, the picomolar doses of indirubin, unlike the equimolar doses of TCDD, increased mRNA levels of this important desmosomal and adherens junctions constituent. These present data suggest that the outcome of AhR activation induced by indirubin at concentrations expected in vivo may differ from the AhR signalling triggered by exogenous toxic ligands, such as TCDD.
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Affiliation(s)
- Jiřina Procházková
- Department of Cytokinetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 61265 Brno, Czech Republic
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Dietrich C, Kaina B. The aryl hydrocarbon receptor (AhR) in the regulation of cell-cell contact and tumor growth. Carcinogenesis 2010; 31:1319-28. [PMID: 20106901 PMCID: PMC6276890 DOI: 10.1093/carcin/bgq028] [Citation(s) in RCA: 180] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Revised: 01/21/2010] [Accepted: 01/24/2010] [Indexed: 01/26/2023] Open
Abstract
The aryl hydrocarbon receptor (AhR) is a ligand-dependent transcription factor, which is activated by a large group of environmental pollutants including polycyclic aromatic hydrocarbons, dioxins and planar polychlorinated biphenyls. Ligand binding leads to dimerization of the AhR with aryl hydrocarbon receptor nuclear translocator and transcriptional activation of several xenobiotic phase I and phase II metabolizing enzymes, such as cytochrome P4501A1 and glutathione-S-transferase, respectively. Since phase I enzymes convert inert carcinogens to active genotoxins, the AhR plays a key role in tumor initiation. Besides this classical route, the AhR mediates tumor promotion and recent evidence suggests that the AhR also plays a role in tumor progression. To date, no mechanistic link could be established between the canonical pathway involving xenobiotic metabolism and AhR-dependent tumor promotion and progression. A hallmark of tumor promotion is unbalanced proliferation, whereas tumor progression is characterized by dedifferentiation, increased motility and metastasis of tumor cells. Tumor progression and presumably also tumor promotion are triggered by loss of cell-cell contact. Cell-cell contact is known to be a critical regulator of proliferation, differentiation and cell motility in vitro and in vivo. Increasing evidence suggests that activation of the AhR may lead to deregulation of cell-cell contact, thereby inducing unbalanced proliferation, dedifferentiation and enhanced motility. In line with this is the finding of increased AhR expression and malignancy in some animal and human cancers. Here, we summarize our current knowledge on non-canonical AhR-driven pathways being involved in deregulation of cell-cell contact and discuss the data with respect to tumor initiation, promotion and progression.
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Affiliation(s)
- Cornelia Dietrich
- Institute of Toxicology, Medical Center of the Johannes Gutenberg-University, Mainz, Germany.
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Shi LZ, Czuprynski CJ. Beta-naphthoflavone causes an AhR-independent inhibition of invasion and intracellular multiplication of Listeria monocytogenes in murine hepatocytes. Microb Pathog 2009; 47:258-66. [PMID: 19715752 DOI: 10.1016/j.micpath.2009.08.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Revised: 08/17/2009] [Accepted: 08/18/2009] [Indexed: 12/19/2022]
Abstract
We recently reported a heretofore unknown role for the aryl hydrocarbon receptor in host resistance to listeriosis in mice. Hepatocytes are an important site for Listeria monocytogenes multiplication in vivo. In this study, we investigated whether activation of AhR in TIB73 murine embryonic hepatocytes affects the ingestion and intracellular multiplication of L. monocytogenes. Treatment of TIB73 cells with the AhR agonist beta-naphthoflavone (BNF) significantly inhibited the ingestion and intracellular growth of L. monocytogenes. The inhibitory effects of BNF were dose-dependent and correlated with up-regulation of CYP1A1. Surprisingly, pretreatment with AhR antagonists (3'-MNF or alpha-naphthoflavone) or knocking-down of AhR with siRNA did not abolish the inhibitory effects of BNF. Moreover, the inhibitory effects of BNF on invasion and intracellular growth of L. monocytogenes by BNF were observed in AhR-deficient (CRL-2710), or ARNT-dysfunctional (CRL-2717) Hepa cells. We also observed similar inhibitory effects of BNF treatment using primary hepatocytes recovered from AhR(+/-) or AhR(-/-) mice. Moreover, the prototypic AhR agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) did not inhibit the invasion and intracellular growth of L. monocytogenes in TIB73 cells. Mechanistic studies demonstrated that ROS, but not TNF-alpha or iNOS, plays an important role in mediating BNF-induced inhibition. In conclusion, BNF caused an AhR-independent inhibition of ingestion and intracellular multiplication of L. monocytogenes in murine hepatocytes, mediated in part by production of ROS.
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Affiliation(s)
- Lewis Zhichang Shi
- Department of Pathobiological Sciences, University of Wisconsin, Madison, WI 53706, USA.
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Bradshaw TD, Bell DR. Relevance of the aryl hydrocarbon receptor (AhR) for clinical toxicology. Clin Toxicol (Phila) 2009; 47:632-42. [PMID: 19640236 DOI: 10.1080/15563650903140423] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
INTRODUCTION The aryl hydrocarbon receptor (AhR) is a cellular signaling molecule infamous for mediating the toxicity of dioxins and related compounds. AIM The aim of this review is to provide a background of AhR and to examine critically its role in chemical toxicity, in physiological systems, and its interaction with drugs and other compounds. TOXICITY The AhR is essential for the toxicity of dioxins and related chemicals. The AhR mediates the exquisite sensitivity of animals to dioxins, where as little as 2 ng/kg/day can yield striking adverse effects. PHYSIOLOGICAL ROLE OF AHR: The wide variety of adverse effects of dioxin argues for an important role of the AhR in a variety of physiological systems. Recent investigations have highlighted the role of AhR in the development of the brain and vasculature. DRUGS AND OTHER CHEMICAL ACTIVATORS OF AHR: The development of AhR agonists during drug development programs is sometimes inadvertent, but sometimes the target of development, and is yet further confirmation of the likely importance of AhR signaling in constitutive physiology. The presence of AhR agonists in the diet such as indolo-(3,2-b)-carbazole and 3,3'-diindolylmethane (metabolized from indole 3-carbinol), flavonoids, and sulforaphane and of endogenous activators of this signaling system such as eicosanoids, indirubin, bilirubin, cAMP, and tryptophan are suggestive that AhR activation is a normal physiological process and that it is the persistent and high-level stimulation of AhR by dioxins that is responsible for toxicity. CONCLUSIONS AhR-mediated toxicity and physiology are highly relevant to clinical toxicology and drug development.
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Vondráček J, Krčmář P, Procházková J, Trilecová L, Gavelová M, Skálová L, Szotáková B, Bunček M, Radilová H, Kozubík A, Machala M. The role of aryl hydrocarbon receptor in regulation of enzymes involved in metabolic activation of polycyclic aromatic hydrocarbons in a model of rat liver progenitor cells. Chem Biol Interact 2009; 180:226-37. [DOI: 10.1016/j.cbi.2009.03.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2008] [Revised: 03/10/2009] [Accepted: 03/16/2009] [Indexed: 11/30/2022]
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Topinka J, Marvanová S, Vondrácek J, Sevastyanova O, Nováková Z, Krcmár P, Pencíková K, Machala M. DNA adducts formation and induction of apoptosis in rat liver epithelial 'stem-like' cells exposed to carcinogenic polycyclic aromatic hydrocarbons. Mutat Res 2008; 638:122-132. [PMID: 17961608 DOI: 10.1016/j.mrfmmm.2007.09.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Revised: 09/06/2007] [Accepted: 09/11/2007] [Indexed: 05/25/2023]
Abstract
The bipotent liver progenitor cells, so called oval cells, may participate at the early stages of hepatocarcinogenesis induced by chemical carcinogens. Unlike in mature parenchymal cells, little is known about formation of DNA adducts and other genotoxic events in oval cells. In the present study, we employed spontaneously immortalized rat liver WB-F344 cell line, which is an established in vitro model of oval cells, in order to study genotoxic effects of selected carcinogenic polycyclic aromatic hydrocarbons (PAHs). With exception of dibenzo[a,l]pyrene, and partly also benzo[g]chrysene and benz[a]anthracene, all other PAHs under the study induced high levels of CYP1A1 and CYP1B1 mRNA. In contrast, we observed distinct genotoxic and cytotoxic potencies of PAHs. Dibenzo[a,l]pyrene, and to a lesser extent also benzo[a]pyrene, benzo[g]chrysene and dibenzo[a,e]pyrene, formed high levels of DNA adducts. This was accompanied with accumulation of Ser-15 phosphorylated form of p53 protein and induction of apoptosis. Contrary to that, benz[a]anthracene, chrysene, benzo[b]fluoranthene and dibenzo[a,h]anthracene induced only low amounts of DNA adducts formation and minimal apoptosis, without exerting significant effects on p53 phosphorylation. Finally, we studied effects of 2,4,3',5'-tetramethoxystilbene and fluoranthene, inhibitors of CYP1B1 activity, which plays a central role in metabolic activation of dibenzo[a,l]pyrene. In a dose-dependent manner, both compounds inhibited apoptosis induced by dibenzo[a,l]pyrene, suggesting that it interferes with the metabolic activation of the latter one. The present data show that in model cell line sharing phenotypic properties with oval cells, PAHs can be efficiently metabolized to form ultimate genotoxic metabolites. Liver progenitor cells could be thus susceptible to this type of genotoxic insult, which makes WB-F344 cell line a useful tool for studies of genotoxic effects of organic contaminants in liver cells. Our results also suggest that, unlike in mature hepatocytes, CYP1B1 might be a primary enzyme responsible for formation of DNA adducts in liver progenitor cells.
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Affiliation(s)
- Jan Topinka
- Laboratory of Genetic Ecotoxicology, Institute of Experimental Medicine, AS CR, 142 20 Prague, Czech Republic
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Umannová L, Zatloukalová J, Machala M, Krcmár P, Májková Z, Hennig B, Kozubík A, Vondrácek J. Tumor Necrosis Factor-α Modulates Effects of Aryl Hydrocarbon Receptor Ligands on Cell Proliferation and Expression of Cytochrome P450 Enzymes in Rat Liver “Stem-Like” Cells. Toxicol Sci 2007; 99:79-89. [PMID: 17557910 DOI: 10.1093/toxsci/kfm149] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Various liver diseases lead to an extensive inflammatory response and release of a number of proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha). This cytokine is known to play a major role in liver regeneration as well as in carcinogenesis. We investigated possible interactions of TNF-alpha with ligands of the aryl hydrocarbon receptor (AhR) and known liver carcinogens, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and coplanar 3,3',4,4',5-pentachlorobiphenyl (PCB 126). These compounds have been previously found to disrupt cell cycle control in contact-inhibited rat liver WB-F344 cells, an in vitro model of adult liver progenitor cells. TNF-alpha itself had no significant effect on the proliferation/apoptosis ratio in the WB-F344 cell line. However, it significantly potentiated proliferative effects of low picomolar range doses of both TCDD and PCB 126, leading to an increase in cell numbers, as well as an increased percentage of cells entering the S-phase of the cell cycle. The combination of TNF-alpha with low concentrations of AhR ligands increased both messenger RNA (mRNA) and protein levels of cyclin A, a principle cyclin involved in disruption of contact inhibition. TNF-alpha temporarily inhibited AhR-dependent induction of cytochrome P450 1A1 (CYP1A1). In contrast, TNF-alpha significantly enhanced induction of CYP1B1 at both mRNA and protein levels, by a mechanism, which was independent of nuclear factor-kappaB activation. These results suggest that TNF-alpha can significantly amplify effects of AhR ligands on deregulation of cell proliferation control, as well as on expression of CYP1B1, which is involved in metabolic activation of a number of mutagenic compounds.
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Affiliation(s)
- Lenka Umannová
- Laboratory of Cytokinetics, Institute of Biophysics, 62165 Brno, Czech Republic
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