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Abstract
The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that is best known for mediating the toxicity and tumour-promoting properties of the carcinogen 2,3,7,8-tetrachlorodibenzo-p-dioxin, commonly referred to as ‘dioxin’. AHR influences the major stages of tumorigenesis — initiation, promotion, progression and metastasis — and physiologically relevant AHR ligands are often formed during disease states or during heightened innate and adaptive immune responses. Interestingly, ligand specificity and affinity vary between rodents and humans. Studies of aggressive tumours and tumour cell lines show increased levels of AHR and constitutive localization of this receptor in the nucleus. This suggests that the AHR is chronically activated in tumours, thus facilitating tumour progression. This Review discusses the role of AHR in tumorigenesis and the potential for therapeutic modulation of its activity in tumours.
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202
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Li ZD, Wang K, Yang XW, Zhuang ZG, Wang JJ, Tong XW. Expression of aryl hydrocarbon receptor in relation to p53 status and clinicopathological parameters in breast cancer. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2014; 7:7931-7937. [PMID: 25550834 PMCID: PMC4270523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 07/16/2014] [Indexed: 06/04/2023]
Abstract
The aryl hydrocarbon receptor (AhR) is a ligand activated transcription factor implicated in multiple cellular processes and its expression has been shown to play a critical role in tumorigenesis. However, the role of AhR in tumorigenesis of breast cancer remains unclear. In the current study, we investigated the expression levels of AhR in breast lesions and assessing the correlation between AhR expression and clinicopathological variables using breast cancer tissue microarray. Meanwhile, 10 paired of fresh breast cancer and corresponding non-cancer samples were detected for AhR and p53 expression by Western blot, respectively. Results showed that AhR expression levels in breast cancer tissues were significantly higher than that in the non-cancer tissues. AhR expression was associated with the pathological type and P53 status, but not patients age, tumor grade and TNM, as well as ER, PR, C-erbB2, Ki-67, AR, EGFR status. Moreover, Western blot data suggested a negative correlation between p53 protein and AhR protein expression levels. The results suggest that high levels of AhR were expressed in the majority of breast cancer tissues and closely associated with P53 status and histological types of breast cancer. AHR and its abnormal expression may play an important role in multiple stages of breast cancer progression.
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Affiliation(s)
- Zheng-Dong Li
- Shanghai First Maternity and Infant Hospital, Tongji University School of MedicineShanghai 200040, China
| | - Kai Wang
- Shanghai First Maternity and Infant Hospital, Tongji University School of MedicineShanghai 200040, China
| | - Xin-Wei Yang
- Shanghai TCM Hospital, Shanghai University of TCMShanghai 200071, China
| | - Zhi-Gang Zhuang
- Shanghai First Maternity and Infant Hospital, Tongji University School of MedicineShanghai 200040, China
| | - Jian-Jun Wang
- Tongji Hospital, Tongji University School of MedicineShanghai 200092, China
| | - Xiao-Wen Tong
- Tongji Hospital, Tongji University School of MedicineShanghai 200092, China
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203
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Schneider AJ, Branam AM, Peterson RE. Intersection of AHR and Wnt signaling in development, health, and disease. Int J Mol Sci 2014; 15:17852-85. [PMID: 25286307 PMCID: PMC4227194 DOI: 10.3390/ijms151017852] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 09/04/2014] [Accepted: 09/18/2014] [Indexed: 12/16/2022] Open
Abstract
The AHR (aryl hydrocarbon receptor) and Wnt (wingless-related MMTV integration site) signaling pathways have been conserved throughout evolution. Appropriately regulated signaling through each pathway is necessary for normal development and health, while dysregulation can lead to developmental defects and disease. Though both pathways have been vigorously studied, there is relatively little research exploring the possibility of crosstalk between these pathways. In this review, we provide a brief background on (1) the roles of both AHR and Wnt signaling in development and disease, and (2) the molecular mechanisms that characterize activation of each pathway. We also discuss the need for careful and complete experimental evaluation of each pathway and describe existing research that explores the intersection of AHR and Wnt signaling. Lastly, to illustrate in detail the intersection of AHR and Wnt signaling, we summarize our recent findings which show that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced disruption of Wnt signaling impairs fetal prostate development.
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Affiliation(s)
- Andrew J Schneider
- School of Pharmacy and Molecular and Environmental Toxicology Center University of Wisconsin, Madison, WI 53705, USA.
| | - Amanda M Branam
- School of Pharmacy and Molecular and Environmental Toxicology Center University of Wisconsin, Madison, WI 53705, USA.
| | - Richard E Peterson
- School of Pharmacy and Molecular and Environmental Toxicology Center University of Wisconsin, Madison, WI 53705, USA.
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204
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Do MT, Kim HG, Tran TTP, Khanal T, Choi JH, Chung YC, Jeong TC, Jeong HG. Metformin suppresses CYP1A1 and CYP1B1 expression in breast cancer cells by down-regulating aryl hydrocarbon receptor expression. Toxicol Appl Pharmacol 2014; 280:138-48. [DOI: 10.1016/j.taap.2014.07.021] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 06/26/2014] [Accepted: 07/29/2014] [Indexed: 11/28/2022]
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205
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Frauenstein K, Tigges J, Soshilov AA, Kado S, Raab N, Fritsche E, Haendeler J, Denison MS, Vogel CFA, Haarmann-Stemmann T. Activation of the aryl hydrocarbon receptor by the widely used Src family kinase inhibitor 4-amino-5-(4-chlorophenyl)-7-(dimethylethyl)pyrazolo[3,4-d]pyrimidine (PP2). Arch Toxicol 2014; 89:1329-36. [PMID: 25082669 DOI: 10.1007/s00204-014-1321-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 07/21/2014] [Indexed: 01/16/2023]
Abstract
Small molecular weight protein kinase inhibitors are frequently used tools to unravel the complex network of cellular signal transduction under certain physiological and pathophysiological conditions. 4-amino-5-(4-chlorophenyl)-7-(dimethylethyl)pyrazolo[3,4-d]pyrimidine (PP2) is a widely used compound to block the activity of Src family kinases, the major group of non-receptor tyrosine kinases, which trigger multiple cellular signaling pathways. Here, we show that PP2 induces cytochrome P450 1A1 mRNA expression and enzyme activity in a dose-dependent manner in human HepG2 hepatoma cells and NCTC 2544 keratinocytes. By means of reporter gene assays, RNA interference, electrophoretic mobility shift assay, and competitive ligand-binding assay, we further demonstrate that PP2 is a ligand for the aryl hydrocarbon receptor (AHR), an intracellular chemosensor that regulates xenobiotic metabolism, environmental stress responses, and immune functions. Upon ligand-dependent activation, the AHR translocates into the nucleus and dimerizes with the AHR nuclear translocator (ARNT) to modulate the expression of its target genes. In addition, AHR activation is frequently accompanied by an activation of the tyrosine kinase c-Src, resulting in stimulation of cell-surface receptors and downstream signal transduction. As PP2 activates the AHR/ARNT pathway by simultaneously blocking c-Src-mediated alternative signaling routes, this compound may be a suitable tool to study the contribution of the different AHR-dependent signaling pathways to biological processes and adverse outcomes. On the other hand, the unexpected property of PP2 to stimulate AHR/ARNT signaling should be carefully taken into account in future investigations in order to avoid a false interpretation of experimental results and molecular interrelations.
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Affiliation(s)
- Katrin Frauenstein
- IUF - Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Düsseldorf, Germany
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206
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Winston-McPherson GN, Shu D, Tang W. Synthesis and biological evaluation of 2,3'-diindolylmethanes as agonists of aryl hydrocarbon receptor. Bioorg Med Chem Lett 2014; 24:4023-5. [PMID: 24997686 DOI: 10.1016/j.bmcl.2014.06.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 06/05/2014] [Indexed: 01/30/2023]
Abstract
Recent studies suggest that arylhydrocarbon receptor (AhR) may be a target for a number of diseases. Natural product malassezin is a AhR agonist with an interesting 2,3'-diindolylmethane skeleton. We have prepared a series of analogues of natural product malassezin using our recently developed method and tested the activity of these analogues against AhR in a cell-based assay. We found that a methyl substituent at 1'-N can significantly increase the activity and the 2-formyl group is not critical for some diindolylmethanes.
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Affiliation(s)
| | - Dongxu Shu
- School of Pharmacy, University of Wisconsin, 777 Highland Avenue, Madison, WI 53705, United States; Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, WI 53706, United States
| | - Weiping Tang
- School of Pharmacy, University of Wisconsin, 777 Highland Avenue, Madison, WI 53705, United States; Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, WI 53706, United States.
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207
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Zhu C, Xie Q, Zhao B. The role of AhR in autoimmune regulation and its potential as a therapeutic target against CD4 T cell mediated inflammatory disorder. Int J Mol Sci 2014; 15:10116-35. [PMID: 24905409 PMCID: PMC4100143 DOI: 10.3390/ijms150610116] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 03/26/2014] [Accepted: 03/27/2014] [Indexed: 02/07/2023] Open
Abstract
AhR has recently emerged as a critical physiological regulator of immune responses affecting both innate and adaptive systems. Since the AhR signaling pathway represents an important link between environmental stimulators and immune-mediated inflammatory disorder, it has become the object of great interest among researchers recently. The current review discusses new insights into the mechanisms of action of a select group of inflammatory autoimmune diseases and the ligand-activated AhR signaling pathway. Representative ligands of AhR, both exogenous and endogenous, are also reviewed relative to their potential use as tools for understanding the role of AhR and as potential therapeutics for the treatment of various inflammatory autoimmune diseases, with a focus on CD4 helper T cells, which play important roles both in self-immune tolerance and in inflammatory autoimmune diseases. Evidence indicating the potential use of these ligands in regulating inflammation in various diseases is highlighted, and potential mechanisms of action causing immune system effects mediated by AhR signaling are also discussed. The current review will contribute to a better understanding of the role of AhR and its signaling pathway in CD4 helper T cell mediated inflammatory disorder. Considering the established importance of AhR in immune regulation and its potential as a therapeutic target, we also think that both further investigation into the molecular mechanisms of immune regulation that are mediated by the ligand-specific AhR signaling pathway, and integrated research and development of new therapeutic drug candidates targeting the AhR signaling pathway should be pursued urgently.
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Affiliation(s)
- Conghui Zhu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Qunhui Xie
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Bin Zhao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
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208
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Fent K, Chew G, Li J, Gomez E. Benzotriazole UV-stabilizers and benzotriazole: Antiandrogenic activity in vitro and activation of aryl hydrocarbon receptor pathway in zebrafish eleuthero-embryos. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 482-483:125-36. [PMID: 24642098 DOI: 10.1016/j.scitotenv.2014.02.109] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 02/22/2014] [Accepted: 02/23/2014] [Indexed: 05/14/2023]
Abstract
Benzotriazole UV-stabilizers (BUVs) are applied in materials for protection against UV-irradiation. They are widely used, bioaccumulate and share structural similarities to benzotriazole. Benzotriazole (1HBT) finds application as corrosion inhibitor in dishwashing detergents, antifreeze (vehicles) and aircraft de-icing agent. BUVs and 1HBT are persistent and ubiquitous in the aquatic environment, but there is little understanding of the ecotoxicological implications. Here, we comparatively analyze the hormonal activity in vitro and effects in zebrafish eleuthero-embryos in vivo. 2-(2-Hydroxy-5-methylphenyl)benzotriazole (UV-P), 2-(3-t-butyl-2-hydroxy-5-methylphenyl)-5-chlorobenzotriazole (UV-326), UV-327, UV-328, UV-329 and UV-320 showed no estrogenicity (YES assay) and androgenicity (YAS assay). However, UV-P and 1HBT showed significant antiandrogenic activity. We assessed the transcription profiles of up to 26 genes associated with different toxicological pathways in zebrafish eleuthero-embryos to elucidate potential modes of action of UV-P, UV-326 and 1HBT. Embryos were experimentally exposed for 144hpf to three measured concentrations of 15.8, 70.8, and 690μg/L UV-P, 7.5, 31.7, and 84.3μg/L UV-326 and 7.9, 97.3 and 1197.3μg/L 1HBT. Among the 26 transcripts, the induction of the aryl hydrocarbon receptor (AHR) pathway by UV-P and UV-326 was the most significant finding. UV-P led to dose-related induction of AHR1, ARNT2 and cyp1a1, as well as of phase II enzymes glutathione-S-transferase (gstp1) and ugt1a. UV-326 led to a significant induction of cyp1a1 and AHR2, but down-regulation of gstp1 at 84μg/L. Only little transcriptional alterations occurred in genes related to apoptosis, oxidative stress, hormone receptors, and steroidogenesis including aromatase. 1HBT led to only a few expressional changes at 1197μg/L. Our data lead to the conclusion that UV-P and UV-326 activate the AHR-pathway, whereas 1HBT shows only little transcriptional alterations. It should be noted, however, that effects have been observed at concentration much higher than those occurring in the environment. Forthcoming studies should show whether the observed antiandrogenic activities and transcriptional changes translate into physiological effects .
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Affiliation(s)
- Karl Fent
- University of Applied Sciences and Arts Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz, Switzerland; ETH Zurich, Institute of Biogeochemistry and Pollutant Dynamics, Universitätsstrasse 16, CH-8092 Zürich, Switzerland.
| | - Geraldine Chew
- University of Applied Sciences and Arts Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz, Switzerland
| | - Jun Li
- University of Applied Sciences and Arts Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz, Switzerland
| | - Elena Gomez
- UMR Hydrosciences - Université Montpellier 1, DSESP - Faculté de Pharmacie, BP 1449115, Av. Charles Flahault, F-34093 Montpellier Cedex 05, France
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209
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Xie J, Huang X, Park MS, Pham HM, Chan WK. Differential suppression of the aryl hydrocarbon receptor nuclear translocator-dependent function by an aryl hydrocarbon receptor PAS-A-derived inhibitory molecule. Biochem Pharmacol 2014; 88:253-65. [PMID: 24486526 DOI: 10.1016/j.bcp.2014.01.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 01/16/2014] [Accepted: 01/16/2014] [Indexed: 10/25/2022]
Abstract
The aryl hydrocarbon receptor (AhR) heterodimerizes with the aryl hydrocarbon receptor nuclear translocator (Arnt) for transcriptional regulation. We generated three N-terminal deletion constructs of the human AhR of 12-24 kDa in size--namely D1, D2, and D3--to suppress the Arnt function. We observed that all three deletions interact with the human Arnt with similar affinities. D2, which contains part of the AhR PAS-A domain and interacts with the PAS-A domain of Arnt, inhibits the formation of the AhR gel shift complex. D2 suppresses the 3-methylcholanthrene-induced, dioxin response element (DRE)-driven luciferase activity in Hep3B cells and exogenous Arnt reverses this D2 suppression. D2 suppresses the induction of CYP1A1 at both the message and protein levels in Hep3B cells; however, the CYP1B1 induction is not affected. D2 suppresses the recruitment of Arnt to the cyp1a1 promoter but not to the cyp1b1 promoter, partly because the AhR/Arnt heterodimer binds better to the cyp1b1 DRE than to the cyp1a1 DRE. Interestingly, D2 has no effect on the cobalt chloride-induced, hypoxia inducible factor-1 (HIF-1)-dependent expression of vegf, aldolase c, and ldh-a messages. Our data reveal that the flanking sequences of the DRE contribute to the binding affinity of the AhR/Arnt heterodimer to its endogenous enhancers and the function of AhR and HIF-1 can be differentially suppressed by the D2 inhibitory molecule.
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Affiliation(s)
- Jinghang Xie
- Department of Pharmaceutics and Medicinal Chemistry, Thomas J. Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, CA 95211, USA
| | - Xin Huang
- Department of Pharmacy, Qianfoshan Hospital of Shandong University, Jinan, Shandong, 250014, China
| | - Miki S Park
- Department of Pharmaceutics and Medicinal Chemistry, Thomas J. Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, CA 95211, USA
| | - Hang M Pham
- Department of Pharmaceutics and Medicinal Chemistry, Thomas J. Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, CA 95211, USA
| | - William K Chan
- Department of Pharmaceutics and Medicinal Chemistry, Thomas J. Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, CA 95211, USA.
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