1
|
Kumar LK, Verma SK, Chandel R, Thumar M, Singh D, Onteru SK. Aflatoxin M1 decreases the expression of genes encoding tight junction proteins and influences the intestinal epithelial integrity. Mycotoxin Res 2023; 39:453-467. [PMID: 37794205 DOI: 10.1007/s12550-023-00505-2] [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: 05/18/2023] [Revised: 09/10/2023] [Accepted: 09/12/2023] [Indexed: 10/06/2023]
Abstract
Aflatoxin M1 (AFM1) is a mycotoxin that is commonly found as a milk contaminant, and its presence in milk has been linked to cytotoxicity. The present study aimed to evaluate the acute cytotoxic effects of AFM1 on intestinal Caco-2 cells. Initially, we checked the morphology and viability of Caco-2 cells after treatment with different concentrations of AFM1 (5 ng/L, 50 ng/L, 250 ng/L, 500 ng/L, 1000 ng/L, and 2000 ng/L) for different time intervals (6 h, 12 h, and 24 h). It was found that AFM1 did not show any effect on cell morphology, but 10% decrease in viability above 1000 ng/L after 12 h. Furthermore, DCFDA assay showed increased ROS production after 6 h treatments. qPCR analysis showed an increased expression of epithelial-specific cytoskeleton marker genes, Cytokeratin, Villin, Vimentin, and JAM-1, and a decreased expression of tight junction protein genes, Claudin-1, Occludin, and ZO-1. Similarly, we found an increased expression of Cyp1a1 transcript with an increasing AFM1 concentration and incubation time. This gene expression analysis showed AFM1 can cause disruption of tight junctions between intestinal cells, which was further confirmed by a transwell experiment. In conclusion, consumption of AFM1-contaminated milk does not show any effect on cells morphology and viability but decreases the expression of intestinal barrier transcripts that may lead to the disruption of intestinal barrier function and leaky gut.
Collapse
Affiliation(s)
- Lal Krishan Kumar
- Molecular Endocrinology, Functional Genomics & System Biology Laboratory, Animal Biochemistry Division, ICAR-National Dairy Research Institute, Karnal (Haryana), India, 132001
| | - Surya Kant Verma
- Molecular Endocrinology, Functional Genomics & System Biology Laboratory, Animal Biochemistry Division, ICAR-National Dairy Research Institute, Karnal (Haryana), India, 132001
| | - Rajeev Chandel
- Molecular Endocrinology, Functional Genomics & System Biology Laboratory, Animal Biochemistry Division, ICAR-National Dairy Research Institute, Karnal (Haryana), India, 132001
| | - Meet Thumar
- Molecular Endocrinology, Functional Genomics & System Biology Laboratory, Animal Biochemistry Division, ICAR-National Dairy Research Institute, Karnal (Haryana), India, 132001
| | - Dheer Singh
- Molecular Endocrinology, Functional Genomics & System Biology Laboratory, Animal Biochemistry Division, ICAR-National Dairy Research Institute, Karnal (Haryana), India, 132001
| | - Suneel Kumar Onteru
- Molecular Endocrinology, Functional Genomics & System Biology Laboratory, Animal Biochemistry Division, ICAR-National Dairy Research Institute, Karnal (Haryana), India, 132001.
| |
Collapse
|
2
|
Greer JB, Magnuson JT, McGruer V, Qian L, Dasgupta S, Volz DC, Schlenk D. miR133b Microinjection during Early Development Targets Transcripts of Cardiomyocyte Ion Channels and Induces Oil-like Cardiotoxicity in Zebrafish ( Danio rerio) Embryos. Chem Res Toxicol 2021; 34:2209-2215. [PMID: 34558284 DOI: 10.1021/acs.chemrestox.1c00238] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Previous studies have shown that altered expression of a family of small noncoding RNAs (microRNAs, or miRs) regulates the expression of downstream mRNAs and is associated with diseases and developmental disorders. miR133b is highly expressed in mammalian cardiac and skeletal muscle, and aberrant expression is associated with cardiac disorders and electrophysiological changes in cardiomyocytes. Similarly, cardiac dysfunction has been observed in early life-stage mahi-mahi (Coryphaena hippurus) exposed to crude oil, a phenotype that has been associated with an upregulation of miR133b as well as subsequent downregulation of a delayed rectifier potassium channel (IKr) and calcium signaling genes that are important for proper heart development during embryogenesis. To examine the potential role of miR133b in oil-induced early life-stage cardiotoxicity in fish, cleavage-stage zebrafish (Danio rerio) embryos were either (1) microinjected with ∼3 nL of negative control miR (75 μM) or miR133b (75 μM) or (2) exposed to a treatment solution containing 5 μM benzo(a)pyrene (BaP), a model polycyclic aromatic hydrocarbon, as a positive control. At 72 h post fertilization (hpf), miR133b-injected fish exhibited BaP-like cardiovascular malformations, including a significantly increased pericardial area relative to negative control miR-injected embryos, as well as a significantly reduced eye area. qPCR revealed that miR133b microinjection decreased the abundance of cardiac-specific IKr kcnh6 at 5 hpf, which may contribute to action potential elongation in oil-exposed cardiomyocytes. Additionally, ryanodine receptor 2, a crucial calcium receptor in the sarcoplasmic reticulum, was also downregulated by miR133b. These results indicate that an oil-induced increase in miR133b may contribute to cardiac abnormalities in oil-exposed fish by targeting cardiac-specific genes essential for proper heart development.
Collapse
Affiliation(s)
- Justin B Greer
- Department of Environmental Sciences, University of California, Riverside, California 92521, United States.,U.S. Geological Survey, Western Fisheries Research Center, Seattle, Washington 98115, United States
| | - Jason T Magnuson
- Department of Environmental Sciences, University of California, Riverside, California 92521, United States
| | - Victoria McGruer
- Department of Environmental Sciences, University of California, Riverside, California 92521, United States
| | - Le Qian
- Department of Environmental Sciences, University of California, Riverside, California 92521, United States.,College of Sciences, China Agricultural University, Beijing 100083, China
| | - Subham Dasgupta
- Department of Environmental Sciences, University of California, Riverside, California 92521, United States
| | - David C Volz
- Department of Environmental Sciences, University of California, Riverside, California 92521, United States
| | - Daniel Schlenk
- Department of Environmental Sciences, University of California, Riverside, California 92521, United States.,Institute of Environmental Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| |
Collapse
|
3
|
Olivero-Verbel J, Harkema JR, Roth RA, Ganey PE. Fenofibrate, a peroxisome proliferator-activated receptor-alpha agonist, blocks steatosis and alters the inflammatory response in a mouse model of inflammation-dioxin interaction. Chem Biol Interact 2021; 345:109521. [PMID: 34052195 DOI: 10.1016/j.cbi.2021.109521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 04/07/2021] [Accepted: 05/14/2021] [Indexed: 12/01/2022]
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (dioxin; TCDD) is an environmental contaminant that elicits a variety of toxic effects, many of which are mediated through activation of the aryl hydrocarbon receptor (AhR). Interaction between AhR and the peroxisome proliferator-activated receptor-alpha (PPAR-α), which regulates fatty acid metabolism, has been suggested. Furthermore, with recognition of the prevalence of inflammatory conditions, there is current interest in the potential for inflammatory stress to modulate the response to environmental agents. The aim of this work was to assess the interaction of TCDD with hepatic inflammation modulated by fenofibrate, a PPAR-α agonist. Female, C57BL/6 mice were treated orally with vehicle or fenofibrate (250 mg/kg) for 13 days, and then were given vehicle or 30 μg/kg TCDD. Four days later, the animals received an i.p. injection of lipopolysaccharide-galactosamine (LPS-GalN) (0.05x107 EU/kg and 500 mg/kg, respectively) to incite inflammation, or saline as vehicle control. After 4 h, the mice were euthanized, and blood and liver samples were collected for analysis. Livers of animals treated with TCDD with or without LPS-GalN had increased lipid deposition, and this effect was blocked by fenofibrate. In TCDD/LPS-GalN-treated mice, fenofibrate caused an increase in plasma activity of alanine aminotransferase, a marker of hepatocellular injury. TCDD reduced LPS-GalN-induced apoptosis, an effect that was prevented by fenofibrate pretreatment. LPS-GalN induced an increase in the concentration of interleukin-6 in plasma and accumulation of neutrophils in liver. TCDD exposure enhanced the former response and inhibited the latter one. These results suggest that fenofibrate counteracts the changes in lipid metabolism induced by TCDD but increases inflammation and liver injury in this model of inflammation-TCDD interaction.
Collapse
Affiliation(s)
- Jesus Olivero-Verbel
- Department of Pharmacology and Toxicology. Michigan State University, East Lansing, MI, USA; Environmental and Computational Chemistry Group, School of Pharmaceutical Sciences, University of Cartagena, Cartagena, 130014, Colombia
| | - Jack R Harkema
- Department of Pathobiology and Diagnostic Investigation, Institute for Integrative Toxicology, Michigan State University, USA
| | - Robert A Roth
- Department of Pharmacology and Toxicology. Michigan State University, East Lansing, MI, USA
| | - Patricia E Ganey
- Department of Pharmacology and Toxicology. Michigan State University, East Lansing, MI, USA.
| |
Collapse
|
4
|
Alzahrani AM, Rajendran P. Pinocembrin attenuates benzo(a)pyrene-induced CYP1A1 expression through multiple pathways: An in vitro and in vivo study. J Biochem Mol Toxicol 2021; 35:e22695. [PMID: 33393179 DOI: 10.1002/jbt.22695] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 10/22/2020] [Accepted: 12/03/2020] [Indexed: 12/30/2022]
Abstract
Benzo(a)pyrene [B(a)P], which is a carcinogen, is a substance most typically known in cigarette smoke and considered as an important intermediary of lung cancer. The enzyme CYP1A1 is crucial for the metabolic conversion of B(a)P into the intermediates that induce carcinogenesis. Stimulation of the aryl hydrocarbon receptor, which is regulated by B(a)P, is thought to induce numerous signaling cascades. Interruption in the mitogen-activated protein kinase (MAPK) pathway causes changes in cellular processes and may alter the AhR pathway. The aim of this investigation is to examine the potential ability of a flavonoid pinocembrin (PCB) to alleviate B(a)P toxicity and analyze the underlying molecular mechanisms. We found that PCB inhibited DNA adduct formation by attenuating CYP1A1 expression through the suppression of the AhR/Src/ERK pathways. PCB mitigated the B(a)P-stimulated DNA damage, inhibited Src and ERK1/2 expression, decreased CYP1A1 expression, and reduced the B(a)P-induced stimulation of NF-κB and MAPK signaling in lung epithelial cells. Finally, the activity of CYP1A1 and Src in lung tissues from mice supplemented with PCB was noticeably decreased and lower than that in lung tissues from mice supplemented with B(a)P alone. Collectively, these data suggest that PCB may alleviate the toxic effects of PAHs, which are important environmental pollutants.
Collapse
Affiliation(s)
- Abdullah M Alzahrani
- Department of Biological Sciences, College of Science, King Faisal University, Al Ahsa, Saudi Arabia
| | - Peramaiyan Rajendran
- Department of Biological Sciences, College of Science, King Faisal University, Al Ahsa, Saudi Arabia
| |
Collapse
|
5
|
Arenas-Huertero F, Zaragoza-Ojeda M, Sánchez-Alarcón J, Milić M, Šegvić Klarić M, Montiel-González JM, Valencia-Quintana R. Involvement of Ahr Pathway in Toxicity of Aflatoxins and Other Mycotoxins. Front Microbiol 2019; 10:2347. [PMID: 31681212 PMCID: PMC6798329 DOI: 10.3389/fmicb.2019.02347] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 09/26/2019] [Indexed: 12/18/2022] Open
Abstract
The purpose of this review is to present information about the role of activation of aflatoxins and other mycotoxins, of the aryl hydrocarbon receptor (AhR) pathway. Aflatoxins and other mycotoxins are a diverse group of secondary metabolites that can be contaminants in a broad range of agricultural products and feeds. Some species of Aspergillus, Alternaria, Penicilium, and Fusarium are major producers of mycotoxins, some of which are toxic and carcinogenic. Several aflatoxins are planar molecules that can activate the AhR. AhR participates in the detoxification of several xenobiotic substances and activates phase I and phase II detoxification pathways. But it is important to recognize that AhR activation also affects differentiation, cell adhesion, proliferation, and immune response among others. Any examination of the effects of aflatoxins and other toxins that act as activators to AhR must consider the potential of the disruption of several cellular functions in order to extend the perception thus far about the toxic and carcinogenic effects of these toxins. There have been no Reviews of existing data between the relation of AhR and aflatoxins and this one attempts to give information precisely about this dichotomy.
Collapse
Affiliation(s)
- Francisco Arenas-Huertero
- Experimental Pathology Research Laboratory, Children’s Hospital of Mexico Federico Gómez, Mexico, Mexico
| | - Montserrat Zaragoza-Ojeda
- Experimental Pathology Research Laboratory, Children’s Hospital of Mexico Federico Gómez, Mexico, Mexico
| | - Juana Sánchez-Alarcón
- Rafael Villalobos-Pietrini Laboratory of Genomic Toxicology and Environmental Chemistry, Faculty of Agrobiology, Autonomous University of Tlaxcala, Tlaxcala, Mexico
| | - Mirta Milić
- Mutagenesis Unit, Institute for Medical Research and Occupational Health, Zagreb, Croatia
| | - Maja Šegvić Klarić
- Department of Microbiology, Faculty of Pharmacy and Biochemistry, University of Zagreb, Zagreb, Croatia
| | - José M. Montiel-González
- Rafael Villalobos-Pietrini Laboratory of Genomic Toxicology and Environmental Chemistry, Faculty of Agrobiology, Autonomous University of Tlaxcala, Tlaxcala, Mexico
| | - Rafael Valencia-Quintana
- Rafael Villalobos-Pietrini Laboratory of Genomic Toxicology and Environmental Chemistry, Faculty of Agrobiology, Autonomous University of Tlaxcala, Tlaxcala, Mexico
| |
Collapse
|
6
|
Remote sensing and signaling in kidney proximal tubules stimulates gut microbiome-derived organic anion secretion. Proc Natl Acad Sci U S A 2019; 116:16105-16110. [PMID: 31341083 PMCID: PMC6689987 DOI: 10.1073/pnas.1821809116] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Membrane transporters and receptors are responsible for balancing nutrient and metabolite levels to aid body homeostasis. Here, we report that proximal tubule cells in kidneys sense elevated endogenous, gut microbiome-derived, metabolite levels through EGF receptors and downstream signaling to induce their secretion by up-regulating the organic anion transporter-1 (OAT1). Remote metabolite sensing and signaling was observed in kidneys from healthy volunteers and rats in vivo, leading to induced OAT1 expression and increased removal of indoxyl sulfate, a prototypical microbiome-derived metabolite and uremic toxin. Using 2D and 3D human proximal tubule cell models, we show that indoxyl sulfate induces OAT1 via AhR and EGFR signaling, controlled by miR-223. Concomitantly produced reactive oxygen species (ROS) control OAT1 activity and are balanced by the glutathione pathway, as confirmed by cellular metabolomic profiling. Collectively, we demonstrate remote metabolite sensing and signaling as an effective OAT1 regulation mechanism to maintain plasma metabolite levels by controlling their secretion.
Collapse
|
7
|
Taneja G, Maity S, Jiang W, Moorthy B, Coarfa C, Ghose R. Transcriptomic profiling identifies novel mechanisms of transcriptional regulation of the cytochrome P450 (Cyp)3a11 gene. Sci Rep 2019; 9:6663. [PMID: 31040347 PMCID: PMC6491424 DOI: 10.1038/s41598-019-43248-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 04/04/2019] [Indexed: 02/06/2023] Open
Abstract
Cytochrome P450 (CYP)3A is the most abundant CYP enzyme in the human liver, and a functional impairment of this enzyme leads to unanticipated adverse reactions and therapeutic failures; these reactions result in the early termination of drug development or the withdrawal of drugs from the market. The transcriptional regulation mechanism of the Cyp3a gene is not fully understood and requires a thorough investigation. We mapped the transcriptome of the Cyp3a gene in a mouse model. The Cyp3a gene was induced using the mPXR activator pregnenolone-16alpha-carbonitrile (PCN) and was subsequently downregulated using lipopolysaccharide (LPS). Our objective was to identify the transcription factors (TFs), epigenetic modulators and molecular pathways that are enriched or repressed by PCN and LPS based on a gene set enrichment analysis. Our analysis shows that 113 genes were significantly upregulated (by at least 1.5-fold) with PCN treatment, and that 834 genes were significantly downregulated (by at least 1.5-fold) with LPS treatment. Additionally, the targets of the 536 transcription factors were enriched by a combined treatment of PCN and LPS, and among these, 285 were found to have binding sites on Cyp3a11. Moreover, the repressed targets of the epigenetic markers HDAC1, HDAC3 and EZH2 were further suppressed by LPS treatment and were enhanced by PCN treatment. By identifying and contrasting the transcriptional regulators that are altered by PCN and LPS, our study provides novel insights into the transcriptional regulation of CYP3A in the liver.
Collapse
Affiliation(s)
- Guncha Taneja
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston, 4849 Calhoun Rd., Houston, TX, 77204, USA
- DILIsym Services, A Simulations Plus Company, Research Triangle Park, North Carolina, 27709, USA
| | - Suman Maity
- Advanced Technology Cores, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
| | - Weiwu Jiang
- Department of Pediatrics, Section of Neonatology, Texas Children's Hospital, Baylor College of Medicine, 1102 Bates Avenue, Suite 530, Houston, TX, 77030, USA
| | - Bhagavatula Moorthy
- Department of Pediatrics, Section of Neonatology, Texas Children's Hospital, Baylor College of Medicine, 1102 Bates Avenue, Suite 530, Houston, TX, 77030, USA.
| | - Cristian Coarfa
- Dan L Duncan Comprehensive Cancer Center, Center for Precision Environmental Health, Molecular and Cellular Biology Department, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.
| | - Romi Ghose
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston, 4849 Calhoun Rd., Houston, TX, 77204, USA.
| |
Collapse
|
8
|
Li H, Hong W, Jin X, Li G, Zhou G, Fan L. The aryl hydrocarbon receptor is a novel negative regulator of interleukin-17-mediated signaling and inflammation in vitro. FEBS Lett 2019; 593:952-961. [PMID: 30953345 DOI: 10.1002/1873-3468.13380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 02/24/2019] [Accepted: 03/06/2019] [Indexed: 12/02/2022]
Abstract
Interleukin (IL)-17 plays a critical role in the pathogenesis of inflammation and autoimmune diseases. The aryl hydrocarbon receptor (AHR) is a transcription factor responsible for the elimination of xenobiotic chemicals. However, it remains unknown whether AHR is involved in IL-17 signaling. Here, we demonstrate that knockdown of AHR significantly enhances, while overexpression or activation of AHR inhibits IL-17-induced inflammation in Hela cells. AHR specifically suppresses IL-17-induced p38 activation, and inhibition of p38 activity markedly reverses the effect of AHR knockdown on IL-17-induced inflammation. Mechanistically, AHR physically interacts with TAK1 and mitogen-activated protein kinase kinase 3/6 (MKK3/6) and disrupts TAK1-MKK3/6 interaction, leading to impaired IL-17 signaling. Thus, our study indicates that AHR negatively regulates IL-17-mediated signaling and inflammation at least partially through interfering with the interaction between TAK1 and MKK3/6.
Collapse
Affiliation(s)
- Hui Li
- Department of Medical Oncology, Zhejiang Cancer Hospital, Hangzhou, Zhejiang, China
| | - Wei Hong
- Department of Medical Oncology, Zhejiang Cancer Hospital, Hangzhou, Zhejiang, China
| | - Xiangyu Jin
- Department of Medical Oncology, Zhejiang Cancer Hospital, Hangzhou, Zhejiang, China
| | - Guangliang Li
- Department of Medical Oncology, Zhejiang Cancer Hospital, Hangzhou, Zhejiang, China
| | - Guoming Zhou
- Departments of Clinical Laboratory, Zhejiang Cancer Hospital, Hangzhou, Zhejiang, China
| | - Liping Fan
- Department of Clinical Laboratory, The Second Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| |
Collapse
|
9
|
Meyer-Alert H, Ladermann K, Larsson M, Schiwy S, Hollert H, Keiter SH. A temporal high-resolution investigation of the Ah-receptor pathway during early development of zebrafish (Danio rerio). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2018; 204:117-129. [PMID: 30245344 DOI: 10.1016/j.aquatox.2018.09.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 09/09/2018] [Accepted: 09/11/2018] [Indexed: 06/08/2023]
Abstract
In order to contribute to a comprehensive understanding of the regulating mechanisms of the aryl-hydrocarbon-receptor (AHR) in zebrafish embryos, we aimed to elucidate the interaction of proteins taking part in this signaling pathway during early development of the zebrafish (Danio rerio) after chemical exposure. We managed to illustrate initial transcription processes of the implemented proteins after exposure to two environmentally relevant chemicals: polychlorinated biphenyl 126 (PCB126) and β-Naphthoflavone (BNF). Using qPCR, we quantified mRNA every 4 h until 118 h post fertilization and found the expression of biotransformation enzymes (cyp1 family) and the repressor of the AHR (ahr-r) to be dependent on the duration of chemical exposure and the biodegradability of the compounds. PCB126 induced persistently increased amounts of transcripts as it is not metabolized, whereas activation by BNF was limited to the initial period of exposure. We did not find a clear relation between the amount of transcripts and activity of the induced CYP-proteins, so posttranscriptional mechanisms are likely to regulate biotransformation of BNF. With regard to zebrafish embryos and their application in risk assessment of hazardous chemicals, our examination of the AHR pathway especially supports the relevance of the time point or period of exposure that is used for bioanalytical investigations and consideration of chemical properties determining biodegradability.
Collapse
Affiliation(s)
- Henriette Meyer-Alert
- Department of Ecosystem Analysis, Institute for Environmental Research, ABBt - Aachen Biology and Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany.
| | - Kim Ladermann
- Department of Ecosystem Analysis, Institute for Environmental Research, ABBt - Aachen Biology and Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Maria Larsson
- Man-Technology-Environment Research Centre, School of Science and Technology, Örebro University, Fakultetsgatan 1, 701 82 Örebro, Sweden
| | - Sabrina Schiwy
- Department of Ecosystem Analysis, Institute for Environmental Research, ABBt - Aachen Biology and Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Henner Hollert
- Department of Ecosystem Analysis, Institute for Environmental Research, ABBt - Aachen Biology and Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Steffen H Keiter
- Man-Technology-Environment Research Centre, School of Science and Technology, Örebro University, Fakultetsgatan 1, 701 82 Örebro, Sweden
| |
Collapse
|
10
|
Benzo[a]pyrene activates an AhR/Src/ERK axis that contributes to CYP1A1 induction and stable DNA adducts formation in lung cells. Toxicol Lett 2018; 289:54-62. [DOI: 10.1016/j.toxlet.2018.03.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 02/24/2018] [Accepted: 03/10/2018] [Indexed: 11/20/2022]
|
11
|
Li Y, Wang K, Zou QY, Jiang YZ, Zhou C, Zheng J. ITE Suppresses Angiogenic Responses in Human Artery and Vein Endothelial Cells: Differential Roles of AhR. Reprod Toxicol 2017; 74:181-188. [PMID: 28986273 DOI: 10.1016/j.reprotox.2017.09.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 09/22/2017] [Accepted: 09/27/2017] [Indexed: 12/26/2022]
Abstract
Aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor is involved in regulation of many essential biological processes including vascular development and angiogenesis. 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) is an AhR ligand, which regulates immune responses and cancer cell growth. However, the roles of the ITE/AhR pathway in mediating placental angiogenesis remains elusive. Here, we determined if ITE affected placental angiogenic responses via AhR in human umbilical vein (HUVECs) and artery endothelial (HUAECs) cells in vitro. We observed that ITE dose- and time-dependently inhibited proliferation and viability of HUAECs and HUVECs, whereas it inhibited migration of HUAECs, but not HUVECs. While AhR siRNA significantly suppressed AhR protein expression in HUVECs and HUAECs, it attenuated the ITE-inhibited angiogenic responses of HUAECs, but not HUVECs. Collectively, ITE suppressed angiogenic responses of HUAECs and HUVECs, dependent and independent of AhR, respectively. These data suggest that ITE may regulate placental angiogenesis.
Collapse
Affiliation(s)
- Yan Li
- Department of Obstetrics and Gynecology, University of Wisconsin-Madison, Madison, WI 53715, United States
| | - Kai Wang
- Department of Obstetrics and Gynecology, University of Wisconsin-Madison, Madison, WI 53715, United States
| | - Qing-Yun Zou
- Department of Obstetrics and Gynecology, University of Wisconsin-Madison, Madison, WI 53715, United States
| | - Yi-Zhou Jiang
- Department of Obstetrics and Gynecology, University of Wisconsin-Madison, Madison, WI 53715, United States
| | - Chi Zhou
- Department of Obstetrics and Gynecology, University of Wisconsin-Madison, Madison, WI 53715, United States
| | - Jing Zheng
- Department of Obstetrics and Gynecology, University of Wisconsin-Madison, Madison, WI 53715, United States; Cardiovascular Medicine Center, Affiliated Hospital of Guangdong Medical University, Zhanjiang 524001, Guangdong, China.
| |
Collapse
|
12
|
Occhi G, Barollo S, Regazzo D, Bertazza L, Galuppini F, Guzzardo V, Jaffrain-Rea ML, Vianello F, Ciato D, Ceccato F, Watutantrige-Fernando S, Bisognin A, Bortoluzzi S, Pennelli G, Boscaro M, Scaroni C, Mian C. A constitutive active MAPK/ERK pathway due to BRAFV600E positively regulates AHR pathway in PTC. Oncotarget 2016; 6:32104-14. [PMID: 26392334 PMCID: PMC4741662 DOI: 10.18632/oncotarget.5194] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 09/03/2015] [Indexed: 12/29/2022] Open
Abstract
The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor mediating the toxicity and tumor-promoting properties of dioxin. AHR has been reported to be overexpressed and constitutively active in a variety of solid tumors, but few data are currently available concerning its role in thyroid cancer. In this study we quantitatively explored a series of 51 paired-normal and papillary thyroid carcinoma (PTC) tissues for AHR-related genes. We identified an increased AHR expression/activity in PTC, independently from its nuclear dimerization partner and repressor but strictly related to a constitutive active MAPK/ERK pathway. The AHR up-regulation followed by an increased expression of AHR target genes was confirmed by a meta-analysis of published microarray data, suggesting a ligand-independent active AHR pathway in PTC. In-vitro studies using a PTC-derived cell line (BCPAP) and HEK293 cells showed that BRAFV600E may directly modulate AHR localization, induce AHR expression and activity in an exogenous ligand-independent manner. The AHR pathway might represent a potential novel therapeutic target for PTC in the clinical practice.
Collapse
Affiliation(s)
- Gianluca Occhi
- Department of Biology, University of Padova, Padova, Italy
| | - Susi Barollo
- Endocrinology Division, Department of Medicine, Hospital/University of Padova, Padova, Italy
| | - Daniela Regazzo
- Endocrinology Division, Department of Medicine, Hospital/University of Padova, Padova, Italy
| | - Loris Bertazza
- Endocrinology Division, Department of Medicine, Hospital/University of Padova, Padova, Italy
| | - Francesca Galuppini
- Surgical Pathology & Cytopathology Unit, Department of Medicine, Hospital/University of Padova, Padova, Italy
| | - Vincenza Guzzardo
- Surgical Pathology & Cytopathology Unit, Department of Medicine, Hospital/University of Padova, Padova, Italy
| | - Marie Lise Jaffrain-Rea
- Department of Clinical and Biotechnological Sciences, University of L'Aquila, L'Aquila, Italy.,Neuromed Institute, Department of Neurological Sciences, University of L'Aquila, L'Aquila, Italy
| | - Federica Vianello
- Department of Radiotherapy, Istituto Oncologico del Veneto, IOV-IRCCS, Padova, Italy
| | - Denis Ciato
- Endocrinology Division, Department of Medicine, Hospital/University of Padova, Padova, Italy
| | - Filippo Ceccato
- Endocrinology Division, Department of Medicine, Hospital/University of Padova, Padova, Italy
| | | | | | | | - Gianmaria Pennelli
- Surgical Pathology & Cytopathology Unit, Department of Medicine, Hospital/University of Padova, Padova, Italy
| | - Marco Boscaro
- Endocrinology Division, Department of Medicine, Hospital/University of Padova, Padova, Italy
| | - Carla Scaroni
- Endocrinology Division, Department of Medicine, Hospital/University of Padova, Padova, Italy
| | - Caterina Mian
- Endocrinology Division, Department of Medicine, Hospital/University of Padova, Padova, Italy
| |
Collapse
|
13
|
Banerjee B, Chakraborty S, Ghosh D, Raha S, Sen PC, Jana K. Benzo(a)pyrene Induced p53 Mediated Male Germ Cell Apoptosis: Synergistic Protective Effects of Curcumin and Resveratrol. Front Pharmacol 2016; 7:245. [PMID: 27551266 PMCID: PMC4976231 DOI: 10.3389/fphar.2016.00245] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 07/25/2016] [Indexed: 12/02/2022] Open
Abstract
Benzo(a)pyrene (B(a)P) is an environmental toxicant that induces male germ cell apoptosis. Curcumin and resveratrol are phytochemicals with cytoprotective and anti-oxidative properties. At the same time resveratrol is also a natural Aryl hydrocarbon Receptor (AhR) antagonist. Our present study in isolated testicular germ cell population from adult male Wistar rats, highlighted the synergistic protective effect of curcumin and resveratrol against B(a)P induced p53 mediated germ cell apoptosis. Curcumin-resveratrol significantly prevented B(a)P induced decrease in sperm cell count and motility, as well as increased serum testosterone level. Curcumin-resveratrol co-treatment actively protected B(a)P induced testicular germ cell apoptosis. Curcumin-resveratrol co-treatment decreased the expression of pro-apoptotic proteins like cleaved caspase 3, 8 and 9, cleaved PARP, Apaf1, FasL, tBid. Curcumin-resveratrol co-treatment decreased Bax/Bcl2 ratio, mitochondria to cytosolic translocation of cytochrome c and activated the survival protein Akt. Curcumin-resveratrol decreased the expression of p53 dependent apoptotic genes like Fas, FasL, Bax, Bcl2, and Apaf1. B(a)P induced testicular reactive oxygen species (ROS) generation and oxidative stress were significantly ameliorated with curcumin and resveratrol. Curcumin-resveratrol co-treatment prevented B(a)P induced nuclear translocation of AhR and CYP1A1 (Cytochrome P4501A1) expression. The combinatorial treatment significantly inhibited B(a)P induced ERK 1/2, p38 MAPK and JNK 1/2 activation. B(a)P treatment increased the expression of p53 and its phosphorylation (p53 ser 15). Curcumin-resveratrol co-treatment significantly decreased p53 level and its phosphorylation (p53 ser 15). The study concludes that curcumin-resveratrol synergistically modulated MAPKs and p53, prevented oxidative stress, regulated the expression of pro and anti-apoptotic proteins as well as the proteins involved in B(a)P metabolism thus protected germ cells from B(a)P induced apoptosis.
Collapse
Affiliation(s)
- Bhaswati Banerjee
- Division of Molecular Medicine, Bose Institute, Calcutta Improvement Trust Scheme VIIM Kolkata, India
| | - Supriya Chakraborty
- Division of Molecular Medicine, Bose Institute, Calcutta Improvement Trust Scheme VIIM Kolkata, India
| | - Debidas Ghosh
- Department of Bio-Medical Laboratory Science and Management, Vidyasagar University Midnapore, India
| | - Sanghamitra Raha
- Department of Biotechnology and Integrated Sciences, Visva Bharati Shantiniketan, India
| | - Parimal C Sen
- Division of Molecular Medicine, Bose Institute, Calcutta Improvement Trust Scheme VIIM Kolkata, India
| | - Kuladip Jana
- Division of Molecular Medicine, Bose Institute, Calcutta Improvement Trust Scheme VIIM Kolkata, India
| |
Collapse
|
14
|
Joiakim A, Mathieu PA, Shelp C, Boerner J, Reiners JJ. Epidermal Growth Factor Receptor Kinase Inhibitors Synergize with TCDD to Induce CYP1A1/1A2 in Human Breast Epithelial MCF10A Cells. Drug Metab Dispos 2016; 44:665-71. [PMID: 26953171 PMCID: PMC11024934 DOI: 10.1124/dmd.115.066274] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 03/03/2016] [Indexed: 04/20/2024] Open
Abstract
CYP1A1 and CYP1A2 are transcriptionally activated in the human normal breast epithelial cell line MCF10A following exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Shifting MCF10A cultures to medium deficient in serum and epidermal growth factor (EGF) caused rapid reductions in the activated (i.e., phosphorylated) forms of extracellular regulated kinases (ERKs) and the epidermal growth factor receptor (EGFR). Shifting to serum/EGF-deficient medium also enhanced TCDD-mediated induction of cytochrome P450 (CYP)1A1 Treatment of cells cultured in complete medium with the EGFR inhibitors gefitinib (Iressa), AG1478, and CI-1033 resulted in concentration-dependent reductions of active EGFR and ERKs, and increased CYP1A1 mRNA content ∼3- to 18-fold above basal level. EGFR inhibitors synergized with TCDD and resulted in transient CYP1A1 and CYP1A2 mRNA accumulations ∼8-fold greater (maximum at 5 hours) than that achieved with only TCDD. AG1478, gefitinib, and TCDD individually induced small increases (∼1.2- to 2.5-fold) in CYP1A1 protein content but did not cause additive or synergistic accumulations of CYP1A1 protein when used in combination. The mitogen-activated protein kinase kinase inhibitor PD184352 inhibited ERK and EGFR activation in a concentration-dependent fashion without causing CYP1A1 mRNA accumulation. However, cotreatment with PD184352 potentiated TCDD-mediated CYP1A1 induction. TCDD-mediated induction of CYP1A1 in MCF7-TET on-EGFR cells, a MCF7 variant in which EGFR expression can be controlled, was not affected by the activity status of EGFR or ERKs. Hence, EGFR signaling mutes both basal and ligand-induced expression of two aryl hydrocarbon receptor-responsive P450s in MCF10A cultures. However, these effects are cell context-dependent. Furthermore, CYP1A1 mRNA and protein abundance are not closely coupled in MCF10A cultures.
Collapse
Affiliation(s)
- Aby Joiakim
- Institute of Environmental Health Sciences, Wayne State University, Detroit, Michigan (A.J., P.A.M., J.J.R.); Department of Pharmacology (C.S., J.J.R.) and Department of Oncology (J.B.), Wayne State University School of Medicine, Karmanos Cancer Institute, Detroit, Michigan
| | - Patricia A Mathieu
- Institute of Environmental Health Sciences, Wayne State University, Detroit, Michigan (A.J., P.A.M., J.J.R.); Department of Pharmacology (C.S., J.J.R.) and Department of Oncology (J.B.), Wayne State University School of Medicine, Karmanos Cancer Institute, Detroit, Michigan
| | - Catherine Shelp
- Institute of Environmental Health Sciences, Wayne State University, Detroit, Michigan (A.J., P.A.M., J.J.R.); Department of Pharmacology (C.S., J.J.R.) and Department of Oncology (J.B.), Wayne State University School of Medicine, Karmanos Cancer Institute, Detroit, Michigan
| | - Julie Boerner
- Institute of Environmental Health Sciences, Wayne State University, Detroit, Michigan (A.J., P.A.M., J.J.R.); Department of Pharmacology (C.S., J.J.R.) and Department of Oncology (J.B.), Wayne State University School of Medicine, Karmanos Cancer Institute, Detroit, Michigan
| | - John J Reiners
- Institute of Environmental Health Sciences, Wayne State University, Detroit, Michigan (A.J., P.A.M., J.J.R.); Department of Pharmacology (C.S., J.J.R.) and Department of Oncology (J.B.), Wayne State University School of Medicine, Karmanos Cancer Institute, Detroit, Michigan
| |
Collapse
|
15
|
Han EH, Kim HG, Lee EJ, Jeong HG. Endosulfan Induces CYP1A1 Expression Mediated through Aryl Hydrocarbon Receptor Signal Transduction by Protein Kinase C. Toxicol Res 2016; 31:339-45. [PMID: 26877836 PMCID: PMC4751443 DOI: 10.5487/tr.2015.31.4.339] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
CYP1A1 is a phase I xenobiotic-metabolizing enzyme whose expression is mainly driven by AhR. Endosulfan is an organochlorine pesticide used agriculturally for a wide range of crops. In this study, we investigated the effect of endosulfan on CYP1A1 expression and regulation. Endosulfan significantly increased CYP1A1 enzyme activity as well as mRNA and protein levels. In addition, endosulfan markedly induced XRE transcriptional activity. CH-223191, an AhR antagonist, blocked the endosulfan-induced increase in CYP1A1 mRNA and protein expression. Moreover, endosulfan did not induce CYP1A1 gene expression in AhR-deficient mutant cells. Furthermore, endosulfan enhanced the phosphorylation of calcium calmodulin (CaM)-dependent protein kinase (CaMK) and protein kinase C (PKC). In conclusion, endosulfan-induced up-regulation of CYP1A1 is associated with AhR activation, which may be mediated by PKC-dependent pathways.
Collapse
Affiliation(s)
- Eun Hee Han
- Drug & Disease Target Group, Division of Bioconvergence Analysis, Korea Basic Science Institute, Daejeon, Korea; Biological Analysis Science, University of Science and Technology, Daejeon, Korea
| | - Hyung Gyun Kim
- Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon, Korea
| | - Eun Ji Lee
- Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon, Korea
| | - Hye Gwang Jeong
- Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon, Korea
| |
Collapse
|
16
|
Li Y, Wang K, Zou QY, Magness RR, Zheng J. 2,3,7,8-Tetrachlorodibenzo-p-dioxin differentially suppresses angiogenic responses in human placental vein and artery endothelial cells. Toxicology 2015; 336:70-8. [PMID: 26275813 DOI: 10.1016/j.tox.2015.08.003] [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] [Received: 07/03/2015] [Revised: 08/06/2015] [Accepted: 08/09/2015] [Indexed: 10/23/2022]
Abstract
Placental angiogenesis is dramatically increased during pregnancy in association with the elevated placental blood flows to support the rapidly growing fetus. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is an environmental toxicant and a ligand of aryl hydrocarbon receptor (AhR). Herein, we investigated the effects of TCDD on proliferation, migration, and viability of fetoplacental endothelial cells in response to a complete growth medium which contained serum and growth supplement using human umbilical cord vein (HUVECs) and artery (HUAECs) cells as models. We found that TCDD dose- and time-dependently inhibited (p < 0.05) proliferation of HUVECs and HUAECs. Treatment with TCDD at 10 nM for 6 days inhibited (p < 0.05) migration (by ∼ 30%) of HUAECs, but not HUVECs. TCDD at 10nM also decreased (p < 0.05) viability of HUVECs and HUAECs. Interestingly, specific AhR siRNA blocked (p < 0.05) the TCDD-inhibited cellular responses in HUAECs, but not HUVECs. Nonetheless, TCDD at 10nM neither affected the cell cycle progression, nor did it induce cell apoptosis in HUVECs and HUAECs. In addition, TCDD at 10 nM also did not alter activation of ERK1/2 and AKT1 in HUVECs and HUAECs. Collectively, TCDD suppresses proliferation and/or migration (two key steps of angiogenesis) of HUVECs and HUAECs independent and dependent of AhR, respectively. These data suggest that TCDD inhibited growth of HUVECs and HUAECs via decreasing cell viability. Thus, TCDD may inhibit fetoplacental angiogenesis, leading to negative pregnancy outcomes.
Collapse
Affiliation(s)
- Yan Li
- Department of Obstetrics and Gynecology, Perinatal Research Laboratories, University of Wisconsin-Madison, Madison, WI 53715, USA
| | - Kai Wang
- Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai 200040, PR China
| | - Qing-Yun Zou
- Department of Obstetrics and Gynecology, Perinatal Research Laboratories, University of Wisconsin-Madison, Madison, WI 53715, USA
| | - Ronald R Magness
- Department of Obstetrics and Gynecology, Perinatal Research Laboratories, University of Wisconsin-Madison, Madison, WI 53715, USA; Departments of Pediatrics, University of Wisconsin-Madison, Madison, WI 53715, USA; Department of Animal Sciences, University of Wisconsin-Madison, Madison, WI 53715, USA
| | - Jing Zheng
- Department of Obstetrics and Gynecology, Perinatal Research Laboratories, University of Wisconsin-Madison, Madison, WI 53715, USA; Department of Cardiovascular Medicine, Affiliated Hospital of Guangdong Medical College, Zhanjiang 524001, Guangdong, PR China.
| |
Collapse
|
17
|
Mary VS, Valdehita A, Navas JM, Rubinstein HR, Fernández-Cruz ML. Effects of aflatoxin B1, fumonisin B1 and their mixture on the aryl hydrocarbon receptor and cytochrome P450 1A induction. Food Chem Toxicol 2015; 75:104-11. [DOI: 10.1016/j.fct.2014.10.030] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 10/22/2014] [Accepted: 10/25/2014] [Indexed: 11/30/2022]
|
18
|
Kabátková M, Svobodová J, Pěnčíková K, Mohatad DS, Šmerdová L, Kozubík A, Machala M, Vondráček J. Interactive effects of inflammatory cytokine and abundant low-molecular-weight PAHs on inhibition of gap junctional intercellular communication, disruption of cell proliferation control, and the AhR-dependent transcription. Toxicol Lett 2015; 232:113-21. [DOI: 10.1016/j.toxlet.2014.09.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 09/23/2014] [Accepted: 09/26/2014] [Indexed: 12/11/2022]
|
19
|
Li Y, Wang K, Jiang YZ, Chang XW, Dai CF, Zheng J. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) inhibits human ovarian cancer cell proliferation. Cell Oncol (Dordr) 2014; 37:429-37. [PMID: 25404385 DOI: 10.1007/s13402-014-0206-4] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/20/2014] [Indexed: 01/06/2023] Open
Abstract
PURPOSE The aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor, mediates a broad spectrum of biological processes, including ovarian growth and ovulation. Recently, we found that an endogenous AhR ligand (ITE) can inhibit ovarian cancer proliferation and migration via the AhR. Here, we tested whether 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, an exogenous AhR ligand) may exert similar anti-ovarian cancer activities using human ovarian cancer and non-cancerous human ovarian surface epithelial cells. METHODS Two human ovarian cancer cell lines (SKOV-3 and OVCAR-3) and one human ovarian surface epithelial cell line (IOSE-385) were used. Cell proliferation and migration activities were determined using crystal violet and FluoroBlok insert system assays, respectively. AhR protein expression was assessed by Western blotting. Expression of cytochrome P450, family 1, member A1 (CYP1A1) and member B1 (CYP1B1) mRNA was assessed by qPCR. Small interfering RNAs (siRNAs) were used to knock down AhR expression. RESULTS We found that TCDD dose-dependently suppressed OVCAR-3 cell proliferation, with a maximum effect (~70% reduction) at 100 nM. However, TCDD did not affect SKOV-3 and IOSE-385 cell proliferation and migration. The estimated IC50 of TCDD for inhibiting OVCAR-3 cell proliferation was 4.6 nM. At 10 nM, TCDD time-dependently decreased AhR protein levels, while it significantly increased CYP1A1 and CYP1B1 mRNA levels in SKOV-3, OVCAR-3 and IOSE-385 cells, indicating activation of AhR signaling. siRNA-mediated AhR knockdown readily blocked TCDD-mediated suppression of OVCAR-3 cell proliferation. CONCLUSION Our data indicate that TCDD can suppress human ovarian cancer cell proliferation via the AhR signaling pathway and that TCDD exhibits an anti-proliferative activity in at least a subset of human ovarian cancer cells.
Collapse
Affiliation(s)
- Yan Li
- Department of Obstetrics and Gynecology, University of Wisconsin, 202 S. Park St., Madison, WI, 53715, USA
| | | | | | | | | | | |
Collapse
|
20
|
Kurita H, Schnekenburger M, Ovesen JL, Xia Y, Puga A. The Ah receptor recruits IKKα to its target binding motifs to phosphorylate serine-10 in histone H3 required for transcriptional activation. Toxicol Sci 2014; 139:121-32. [PMID: 24519526 DOI: 10.1093/toxsci/kfu027] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Aryl hydrocarbon receptor (AHR) activation by xenobiotic ligands such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is key to their toxicity. Following activation and nuclear translocation, AHR heterodimerizes with the AHR nuclear translocator (ARNT) and binds to AHR response elements (AhREs) in the enhancer of target genes, of which Cyp1a1 is the prototype. Previously, we showed that concomitant with AHR binding, histone H3 in the Cyp1a1 enhancer-promoter AhRE cluster became phosphorylated in serine-10 (H3S10), suggesting that the ligand-activated AHR recruited one or more kinases to the enhancer chromatin to phosphorylate this residue. To test this hypothesis, we used mouse hepatoma Hepa-1c1c7 cells and their c35 mutant derivative, lacking a functional AHR, to search for candidate kinases that would phosphorylate H3S10 in an AHR dependent manner. Using chromatin immunoprecipitation with antibodies to a comprehensive set of protein kinases, we identified three kinases, IκB kinase α (IKKα), mitogen and stress activated protein kinase 1 (MSK1), and mitogen and stress activated protein kinase 2 (MSK2), whose binding to the Cyp1a1 enhancer was significantly increased by TCDD in Hepa-1c1c7 cells and absent in control c35 cells. Complexes of AHR, ARNT, and IKKα could be coimmunoprecipitated from nuclei of TCDD treated Hepa-1c1c7 cells and shRNA-mediated IKKα knockdown inhibited both H3S10 phosphorylation in the Cyp1a1 enhancer and the induction of Cyp1a1, Aldh3a1, and Nqo1 in TCDD-treated cells. We conclude that AHR recruits IKKα to the promoter of its target genes and that AHR-mediated H3S10 phosphorylation is a key epigenetic requirement for induction of AHR targets. Given the role of H3S10ph in regulation of chromosome condensation, AHR-IKKα cross-talk may be a mediator of chromatin remodeling by environmental agents.
Collapse
Affiliation(s)
- Hisaka Kurita
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati, College of Medicine, 3223 Eden Avenue, Cincinnati, OH 45267
| | | | | | | | | |
Collapse
|
21
|
Solaimani P, Damoiseaux R, Hankinson O. Genome-wide RNAi high-throughput screen identifies proteins necessary for the AHR-dependent induction of CYP1A1 by 2,3,7,8-tetrachlorodibenzo-p-dioxin. Toxicol Sci 2013; 136:107-19. [PMID: 23997114 DOI: 10.1093/toxsci/kft191] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The aryl hydrocarbon receptor (AHR) has a plethora of physiological roles, and upon dysregulation, carcinogenesis can occur. One target gene of AHR encodes the xenobiotic and drug-metabolizing enzyme CYP1A1, which is inducible by the environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) via the AHR. An siRNA library targeted against over 5600 gene candidates in the druggable genome was used to transfect mouse Hepa-1 cells, which were then treated with TCDD, and subsequently assayed for CYP1A1-dependent ethoxyresorufin-o-deethylase (EROD) activity. Following redundant siRNA activity (RSA) statistical analysis, we identified 93 hits that reduced EROD activity with a p value ≤ .005 and substantiated 39 of these as positive hits in a secondary screening using endoribonuclease-prepared siRNAs (esiRNAs). Twelve of the corresponding gene products were subsequently confirmed to be necessary for the induction of CYP1A1 messenger RNA by TCDD. None of the candidates were deficient in aryl hydrocarbon nuclear translocator expression. However 6 gene products including UBE2i, RAB40C, CRYGD, DCTN4, RBM5, and RAD50 are required for the expression of AHR as well as for induction of CYP1A1. We also found 2 gene products, ARMC8 and TCF20, to be required for the induction of CYP1A1, but our data are ambiguous as to whether they are required for the expression of AHR. In contrast, SIN3A, PDC, TMEM5, and CD9 are not required for AHR expression but are required for the induction of CYP1A1, implicating a direct role in Cyp1a1 transcription. Our methods, although applied to Cyp1a1, could be modified for identifying proteins that regulate other inducible genes.
Collapse
Affiliation(s)
- Parrisa Solaimani
- * Molecular Toxicology Interdepartmental Program, Department of Pathology and Laboratory Medicine, and the Jonsson Comprehensive Cancer Center and
| | | | | |
Collapse
|
22
|
Gerbal-Chaloin S, Iankova I, Maurel P, Daujat-Chavanieu M. Nuclear receptors in the cross-talk of drug metabolism and inflammation. Drug Metab Rev 2013; 45:122-44. [PMID: 23330545 DOI: 10.3109/03602532.2012.756011] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Inflammation and infection have long been known to affect the activity and expression of enzymes involved in hepatic and extrahepatic drug clearance. Significant advances have been made to elucidate the molecular mechanisms underlying the complex cross-talk between inflammation and drug-metabolism alterations. The emergent role of ligand-activated transcriptional regulators, belonging to the nuclear receptor (NR) superfamily, is now well established. The NRs, pregnane X receptor, constitutive androstane receptor, retinoic X receptor, glucocorticoid receptor, and hepatocyte nuclear factor 4, and the basic helix-loop-helix/Per-ARNT-Sim family member, aryl hydrocarbon receptor, are the main regulators of the detoxification function. According to the panel of mediators secreted during inflammation, a cascade of numerous signaling pathways is activated, including nuclear factor kappa B, mitogen-activated protein kinase, and the Janus kinase/signal transducer and activator of transcription pathways. Complex cross-talk is established between these signaling pathways regulating either constitutive or induced gene expression. In most cases, a mutual antagonism between xenosensor and inflammation signaling occurs. This review focuses on the molecular and cellular mechanisms implicated in this cross-talk.
Collapse
|
23
|
Wang K, Li Y, Jiang YZ, Dai CF, Patankar MS, Song JS, Zheng J. An endogenous aryl hydrocarbon receptor ligand inhibits proliferation and migration of human ovarian cancer cells. Cancer Lett 2013; 340:63-71. [PMID: 23851185 DOI: 10.1016/j.canlet.2013.06.026] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 06/20/2013] [Accepted: 06/23/2013] [Indexed: 11/28/2022]
Abstract
The aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor mediates many biological processes. Herein, we investigated if 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE, an endogenous AhR ligand) regulated proliferation and migration of human ovarian cancer cells via AhR. We found that AhR was widely present in many histotypes of ovarian cancer tissues. ITE suppressed OVCAR-3 cell proliferation and SKOV-3 cell migration in vitro, which were blocked by AhR knockdown. ITE also suppressed OVCAR-3 cell growth in mice. These data suggest that the ITE might potentially be used for therapeutic intervention for at least a subset of human ovarian cancer.
Collapse
Affiliation(s)
- Kai Wang
- Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai 200040, PR China.,Department of Obstetrics and Gynecology, University of Wisconsin, Madison, WI 53715, United States
| | - Yan Li
- Department of Obstetrics and Gynecology, University of Wisconsin, Madison, WI 53715, United States
| | - Yi-Zhou Jiang
- Department of Obstetrics and Gynecology, University of Wisconsin, Madison, WI 53715, United States
| | - Cai-Feng Dai
- Department of Obstetrics and Gynecology, University of Wisconsin, Madison, WI 53715, United States.,Qilu Hospital of Shandong University, Jinan 250012, Shandong, PR China
| | - Manish S Patankar
- Department of Obstetrics and Gynecology, University of Wisconsin, Madison, WI 53715, United States
| | - Jia-Sheng Song
- AhR Pharmaceuticals, Inc., Madison, WI 53719, United States
| | - Jing Zheng
- Department of Obstetrics and Gynecology, University of Wisconsin, Madison, WI 53715, United States.,Department of Cardiovascular Medicine, Affiliated Hospital of Guangdong Medical College, Zhanjiang 524001, Guangdong, PR China
| |
Collapse
|
24
|
Testosterone-dependent interaction between androgen receptor and aryl hydrocarbon receptor induces liver receptor homolog 1 expression in rat granulosa cells. Mol Cell Biol 2013; 33:2817-28. [PMID: 23689136 DOI: 10.1128/mcb.00011-13] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Androgens play a major role in the regulation of normal ovarian function; however, they are also involved in the development of ovarian pathologies. These contrasting effects may involve a differential response of granulosa cells to the androgens testosterone (T) and dihydrotestosterone (DHT). To determine the molecular pathways that mediate the distinct effects of T and DHT, we studied the expression of the liver receptor homolog 1 (LRH-1) gene, which is differentially regulated by these steroids. We found that although both T and DHT stimulate androgen receptor (AR) binding to the LRH-1 promoter, DHT prevents T-mediated stimulation of LRH-1 expression. T stimulated the expression of aryl hydrocarbon receptor (AHR) and its interaction with the AR. T also promoted the recruitment of the AR/AHR complex to the LRH-1 promoter. These effects were not mimicked by DHT. We also observed that the activation of extracellular regulated kinases by T is required for AR and AHR interaction. In summary, T, but not DHT, stimulates AHR expression and the interaction between AHR and AR, leading to the stimulation of LRH-1 expression. These findings could explain the distinct response of granulosa cells to T and DHT and provide a molecular mechanism by which DHT negatively affects ovarian function.
Collapse
|
25
|
Fardel O. Cytokines as molecular targets for aryl hydrocarbon receptor ligands: implications for toxicity and xenobiotic detoxification. Expert Opin Drug Metab Toxicol 2012; 9:141-52. [PMID: 23230817 DOI: 10.1517/17425255.2013.738194] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
INTRODUCTION The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor historically known for regulating expression of several important drug-detoxifying proteins. Besides drug metabolism pathways, cytokines have been recently recognized as targeted by the AhR signaling cascade, which may contribute to toxicity and changes in xenobiotic detoxification caused by AhR agonists. AREAS COVERED This article summarizes the nature of the main cytokines regulated by AhR ligands and reviews their involvement in toxic effects of AhR ligands, especially in relation with inflammation. The article also discusses the potential implications for drug detoxification pathways. EXPERT OPINION Even if various cytokines, including inflammatory ones, have already been demonstrated to constitute robust targets for AhR, the exact role played by AhR with respect to inflammation remains to be determined. Further studies are also required to better characterize the molecular mechanisms implicated in regulation of cytokines by AhR ligands and to determine the role that may play AhR-targeted cytokines in alteration of xenobiotic detoxification. Finally, changes in cytokine receptor expression triggered by AhR ligands have additionally to be taken into account to better and more extensively comprehend the role played by AhR in the cytokine/inflammation area.
Collapse
Affiliation(s)
- Olivier Fardel
- Institut de Recherche en Environnement, Santé et Travail (IRSET)/INSERM U 1085, Faculté de Pharmacie, 2 Avenue du Pr Léon Bernard, 35043 Rennes, France.
| |
Collapse
|
26
|
Fang CC, Chen FY, Chen CR, Liu CC, Wong LC, Liu YW, Su JGJ. Cyprodinil as an activator of aryl hydrocarbon receptor. Toxicology 2012; 304:32-40. [PMID: 23228475 DOI: 10.1016/j.tox.2012.11.018] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 11/15/2012] [Accepted: 11/28/2012] [Indexed: 01/19/2023]
Abstract
Cyprodinil is a pyrimidinamine fungicide, used worldwide by agriculture. It is used to protect fruit plants and vegetables from a wide range of pathogens. Benzo[a]pyrene (BaP) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) are toxic environmental pollutants and are prototypes of aryl hydrocarbon receptor (AHR) ligands. Although the structure of cyprodinil distinctly differs from those of BaP and TCDD, our results show that cyprodinil induced nuclear translocation of the AHR, and induced the transcriptional activity of aryl hydrocarbon response element (AHRE). Cyprodinil induced the expression of cytochrome P450 (CYP) 1A1, a well-known AHR-targeted gene, in ovarian granulosa cells, HO23, and hepatoma cells, Hepa-1c1c7. Its induction did not appear in AHR signal-deficient cells, and was blocked by the AHR antagonist, CH-223191. Cyprodinil decreased AHR expression in HO23 cells, resulting in CYP1A1 expression decreasing after it peaked at 9h of treatment in HO23 cells. Dexamethasone is a synthetic agonist of glucocorticoids. Cyprodinil enhanced dexamethasone-induced gene expression, and conversely, its induction of CYP1A1 expression was decreased by dexamethasone in HO23 cells, indicating its induction of crosstalk between the AHR and glucocorticoid receptor and its role as a potential endocrine disrupter. In addition to BaP, TCDD, and an AHR agonist, β-NF, cyprodinil also phosphorylated extracellular signal-regulated kinase (ERK) in HO23 and Hepa-1c1c7 cells, indicating its deregulation of ERK activity. In summary, our results demonstrate that cyprodinil, similar to BaP, acts as an AHR activator, a potential endocrine disrupter, and an ERK disrupter.
Collapse
Affiliation(s)
- Chien-Chung Fang
- Hepato-Gastroenterology, Chiayi Christian Hospital, Chiayi 600, Taiwan, ROC
| | | | | | | | | | | | | |
Collapse
|
27
|
Syed K, Yadav JS. P450 monooxygenases (P450ome) of the model white rot fungus Phanerochaete chrysosporium. Crit Rev Microbiol 2012; 38:339-63. [PMID: 22624627 PMCID: PMC3567848 DOI: 10.3109/1040841x.2012.682050] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Phanerochaete chrysosporium, the model white rot fungus, has been the focus of research for the past about four decades for understanding the mechanisms and processes of biodegradation of the natural aromatic polymer lignin and a broad range of environmental toxic chemicals. The ability to degrade this vast array of xenobiotic compounds was originally attributed to its lignin-degrading enzyme system, mainly the extracellular peroxidases. However, subsequent physiological, biochemical, and/or genetic studies by us and others identified the involvement of a peroxidase-independent oxidoreductase system, the cytochrome P450 monooxygenase system. The whole genome sequence revealed an extraordinarily large P450 contingent (P450ome) with an estimated 149 P450s in this organism. This review focuses on the current status of understanding on the P450 monooxygenase system of P. chrysosproium in terms of pre-genomic and post-genomic identification, structural and evolutionary analysis, transcriptional regulation, redox partners, and functional characterization for its biodegradative potential. Future research on this catalytically diverse oxidoreductase enzyme system and its major role as a newly emerged player in xenobiotic metabolism/degradation is discussed.
Collapse
Affiliation(s)
- Khajamohiddin Syed
- Division of Environmental Genetics and Molecular Toxicology, Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0056, USA
| | - Jagjit S Yadav
- Division of Environmental Genetics and Molecular Toxicology, Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0056, USA
| |
Collapse
|
28
|
Ayed-Boussema I, Pascussi JM, Maurel P, Bacha H, Hassen W. Effect of aflatoxin B1 on nuclear receptors PXR, CAR, and AhR and their target cytochromes P450 mRNA expression in primary cultures of human hepatocytes. Int J Toxicol 2011; 31:86-93. [PMID: 21994236 DOI: 10.1177/1091581811422453] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Aflatoxin B1 (AFB1), one of the most common mycotoxins found in human foods and animal feed, is principally hepatotoxic and hepatocarcinogenic. The aim of the present study was to explore the effect of AFB1 on messenger RNA (mRNA) expression of pregnane X receptor (PXR), constitutive androstane receptor (CAR), and aryl hydrocarbon receptor (AhR) and some of their target cytochromes using primary cultures of human hepatocytes. Our results showed that AFB1, at noncytotoxic increasing concentrations, caused a significant upregulation of cytochrome P 2B6 (CYP2B6), CYP3A5, and to a lesser extent CYP3A4 and CYP2C9. Pregnane X receptor and CAR mRNA expression increased in the 3 treated livers. Aflatoxin B1 was found also to induce an overexpression of CYP1A1 and CYP1A2 genes accompanied by an increase in AhR mRNA expression. These findings suggest that AFB1 could activate PXR, CAR, and AhR; however, further investigations are needed to confirm nuclear receptor activation by AFB1.
Collapse
Affiliation(s)
- Imen Ayed-Boussema
- Laboratoire de Recherche sur les Substances Biologiquement Compatibles, (LRSBC), Rue Avicenne, 5019 Monastir, Tunisia
| | | | | | | | | |
Collapse
|
29
|
Ayed-Boussema I, Pascussi JM, Zaied C, Maurel P, Bacha H, Hassen W. Ochratoxin A induces CYP3A4, 2B6, 3A5, 2C9, 1A1, and CYP1A2 gene expression in primary cultured human hepatocytes: a possible activation of nuclear receptors. Drug Chem Toxicol 2011; 35:71-80. [PMID: 21834667 DOI: 10.3109/01480545.2011.589438] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Ochratoxin A (OTA) is a mycotoxin produced by fungi of two genera: Penicillium and Aspergillus. OTA has been shown to be nephrotoxic, hepatotoxic, teratogenic, and immunotoxic to several species of animals and to cause kidney and liver tumors in mice and rats. Biotransformation of OTA has not been entirely elucidated. Several metabolites have been characterized in vitro and/or in vivo, whereas other metabolites remain to be characterized. At present, data available regarding OTA metabolism and cytochrome inductions concern only rodents or in vitro systems. The aim of the present study was to explore the effect of OTA on mRNA expression of some cytochromes known to be regulated by pregnane X receptor (PXR), constitutive androstane receptor (CAR), and aryl hydrocarbon receptor (AhR), using primary cultures of human hepatocytes. Our results showed that OTA reduced hepatocyte viability in a dose-dependent manner. Using quantitative real-time reverse-transcription polymerase chain reaction, our study showed that treatment of primary cultured human hepatocytes with noncytotoxic increasing concentrations of OTA for 24 hours caused a significant upregulation of CYP3A4, CYP2B6, and, to a lesser extent, CYP3A5 and CYP2C9. PXR mRNA expression increased in only 1 treated liver, whereas CAR mRNA expression was not affected. OTA was found also to induce an overexpression of CYP1A1 and CYP1A2 genes accompanied by an increase in AhR mRNA expression. These findings suggest that OTA could activate PXR and AhR; however, further investigations are needed to confirm nuclear-receptor activation by OTA.
Collapse
Affiliation(s)
- Imen Ayed-Boussema
- Laboratory of Research on Biologically Compatible Compounds, Faculty of Dentistry, Monastir, Tunisia
| | | | | | | | | | | |
Collapse
|
30
|
Ghose R, Omoluabi O, Gandhi A, Shah P, Strohacker K, Carpenter KC, McFarlin B, Guo T. Role of high-fat diet in regulation of gene expression of drug metabolizing enzymes and transporters. Life Sci 2011; 89:57-64. [PMID: 21620874 DOI: 10.1016/j.lfs.2011.05.005] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Revised: 03/18/2011] [Accepted: 05/03/2011] [Indexed: 02/06/2023]
Abstract
AIM Our aim is to investigate the molecular mechanism of regulation of gene expression of drug metabolizing enzymes (DMEs) and transporters in diet-induced obesity. MAIN METHODS Adult male CD1 mice were fed diets containing 60% kcal fat (HFD) or 10% kcal fat (LFD) for 14 weeks. RNA levels of hepatic DMEs, transporters and their regulatory nuclear receptors (NRs) were analyzed by real-time PCR. Activation of cell-signaling components (JNK and NF-κΒ) and pro-inflammatory cytokines (IL-1β, IL-6 and TNFα) were measured in the liver. Finally, the pharmacodynamics of drugs metabolized by DMEs was measured to determine the clinical relevance of our findings. KEY FINDINGS RNA levels of the hepatic phase I (Cyp3a11, Cyp2b10, Cyp2a4) and phase II (Ugt1a1, Sult1a1, Sultn) enzymes were reduced ~30-60% in HFD compared to LFD mice. RNA levels of Cyp2e1, Cyp1a2 and the drug transporters, multidrug resistance proteins, (Mrp)2, Mrp3 and multidrug resistant gene (Mdr)1b were unaltered in HFD mice. Gene expression of the NRs, PXR and CAR and nuclear protein levels of RXRα was reduced in HFD mice. Cytokines, JNK and NF-κΒ were induced in HFD mice. Thus reduction in hepatic gene expression in obesity may be modulated by cross-talk between NRs and inflammation-induced cell-signaling. Sleep time of Midazolam (Cyp3a substrate) was prolonged in HFD mice, while Zoxazolamine (Cyp1a2 and Cyp2e1 substrate)-induced sleep time was unaltered. SIGNIFICANCE This study demonstrates that gene-specific reductions in DMEs can affect specific drugs metabolized by these enzymes, thus providing a rationale to monitor the effectiveness of drug therapy in obese individuals.
Collapse
Affiliation(s)
- Romi Ghose
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston, 1441 Moursund Street, Houston, TX 77030, USA.
| | | | | | | | | | | | | | | |
Collapse
|
31
|
Gilot D, Le Meur N, Giudicelli F, Le Vée M, Lagadic-Gossmann D, Théret N, Fardel O. RNAi-based screening identifies kinases interfering with dioxin-mediated up-regulation of CYP1A1 activity. PLoS One 2011; 6:e18261. [PMID: 21479225 PMCID: PMC3066211 DOI: 10.1371/journal.pone.0018261] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Accepted: 02/23/2011] [Indexed: 11/18/2022] Open
Abstract
Background The aryl hydrocarbon receptor (AhR) is a transcription factor activated by several environmental pollutants, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and involved in carcinogenesis and various physiological processes, including immune response and endocrine functions. Characterization of kinases-related AhR transduction pathway remains an important purpose. Results We performed a kinome-wide siRNA screen in human mammary MCF-7 cells to identify non redundant protein kinases implicated in the up-regulation of cytochrome P-450 (CYP) 1A1 activity, an AhR referent target, in response to TCDD exposure. To this aim, we monitored CYP1A1-related ethoxyresorufin-O-deethylase (EROD) activity and quantified cell density. This normalization was crucial since it allowed us to focus only on siRNA affecting EROD activity and discard siRNA affecting cell density. Analyses of the cell density data allowed us to identify several hits already well-characterized as effectors of the cell cycle and original hits. Collectively, these data fully validated the protocol and the siRNA library. Next, 22 novel candidates were identified as kinases potentially implicated in the up-regulation of CYP1A1 in response to TCDD, without alteration of cell survival or cell proliferation. The siRNA library screen gave a limited number of hits (approximately 3%). Interestingly, four of them are able to bind calmodulin among which the IP3 kinase A (ITPKA) and pregnancy up-regulated non-ubiquitously expressed CaM kinase (PNCK, also named CaMKIβ). Remarkably, for both proteins, their kinase activity depends on the calmodulin binding. Involvement of ITPKA and PNCK in TCDD-mediated CYP1A1 up-regulation was further validated by screening-independent expression knock-down. PNCK was finally shown to regulate activation of CaMKIα, a CaMKI isoform previously reported to interplay with the AhR pathway. Conclusions These data fully support a role for both IP3-related kinase and CaMK isoforms in the AhR signaling cascade. More generally, this study also highlights the interest of large scale loss-of-function screens for characterizing the molecular mechanism of action of environmental contaminants.
Collapse
Affiliation(s)
- David Gilot
- EA 4427 Signalisation et Réponse aux Agents Infectieux et Chimiques, Université de Rennes 1, Institut de Recherche Santé, Environnement et Travail, Institut Fédératif de Recherche 140, Rennes, France.
| | | | | | | | | | | | | |
Collapse
|
32
|
Watabe Y, Nazuka N, Tezuka M, Shimba S. Aryl hydrocarbon receptor functions as a potent coactivator of E2F1-dependent trascription activity. Biol Pharm Bull 2010; 33:389-97. [PMID: 20190398 DOI: 10.1248/bpb.33.389] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that mediates a spectrum of toxic and biological effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin and related compounds. Several reports have shown that the AhR plays an important role in the control of cell-cycle progression, and this function is thought to be partly associated with the tumor promotion activity of dioxin. However, the underling mechanisms are not fully understood. We have previously shown that overexpression of AhR, as well as AhR ligand treatment, stimulates cell proliferation of human lung cancer A549 cells. In AhR-activated cells, the expression levels of DNA synthesis-related genes such as proliferating cell nuclear antigen (PCNA) and RFC38 are notably increased. Expression of these genes is mainly regulated by E2F1, a transcription factor that is crucial for transition of the cell cycle from G1 to S phase. We show here that the transcriptional activity of E2F1 is increased by the AhR agonist treatment and that this effect depends on the presence of AhR. Functional mapping of AhR showed that the Per-Arnt-Sim (PAS) B domain is required for promotion of E2F1 activity. The mechanism involves formation of a complex of AhR and E2F1 on the regulatory region in the E2F1 target gene, followed by recruitment of coactivator activator for thyroid hormone and retinoid receptors (ACTR). Consequently, the results in this study indicate the physiological function of AhR as a potent transcriptional coactivator of E2F1-dependent transcription and implicate the AhR-E2F1 interaction as a part of the mechanism by which AhR/Arnt promotes cell proliferation.
Collapse
Affiliation(s)
- Yuichi Watabe
- Department of Health Science, College of Pharmacy, Nihon University, Funabashi, Chiba 274-8555,Japan
| | | | | | | |
Collapse
|
33
|
Han EH, Kim HG, Im JH, Jeong TC, Jeong HG. Up-regulation of CYP1A1 by rutaecarpine is dependent on aryl hydrocarbon receptor and calcium. Toxicology 2009; 266:38-47. [PMID: 19853001 DOI: 10.1016/j.tox.2009.10.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Revised: 10/12/2009] [Accepted: 10/12/2009] [Indexed: 01/31/2023]
Abstract
Rutaecarpine is a quinazolinocarboline alkaloid isolated from a traditional Chinese medicinal fruit, Evodia rutaecarpa. In the present study, we investigated the effect of rutaecarpine on CYP1A1 expression mediated by [Ca(2+)] and the AhR pathway in mouse hepatoma Hepa-1c1c7 cells. Rutaecarpine also significantly increased CYP1A1 enzyme activity and mRNA and protein levels. Rutaecarpine markedly induced XRE and AhR binding activity. CH-223191, an AhR antagonist, blocked the rutaecarpine-induced CYP1A1 enzyme activity and mRNA and protein expression. In addition, rutaecarpine remarkably induced the phosphorylation of Ca(2+)/calmodulin (CaM)-dependent protein kinase (CaMK). W7 and BAPTA/AM, a CaM antagonist and an intracellular Ca(2+) chelator, respectively, blocked the rutaecarpine-induced CYP1A1 enzyme activity and mRNA and protein expression. These results indicate that rutaecarpine induces CYP1A1 expression through AhR- and calcium-dependent mechanisms.
Collapse
Affiliation(s)
- Eun Hee Han
- Department of Toxicology, College of Pharmacy, Chungnam National University, 220 Gung-dong, Yuseong-Gu, Daejeon 305-764, South Korea
| | | | | | | | | |
Collapse
|
34
|
Ahmed S, Valen E, Sandelin A, Matthews J. Dioxin increases the interaction between aryl hydrocarbon receptor and estrogen receptor alpha at human promoters. Toxicol Sci 2009; 111:254-66. [PMID: 19574409 DOI: 10.1093/toxsci/kfp144] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Recent studies have shown that activated aryl hydrocarbon receptor (AHR) induced the recruitment of estrogen receptor-alpha (ERalpha) to AHR-regulated genes and that AHR is recruited to ERalpha-regulated genes. However, these findings were limited to a small number of well-characterized AHR- or ERalpha-responsive genes with little knowledge of what was occurring at other genomic regions. In this study, we showed using chromatin immunoprecipitation followed by hybridization to promoter focused microarrays (ChIP-chip) that 2,3,7,8-tetrachlorodibenzo-p-dioxin treatment significantly increased the overlap of genomic regions bound by both AHR and ERalpha. Conventional and sequential ChIPs confirmed the recruitment of AHR and ERalpha to many of the identified regions. Transcription factor binding site analysis revealed an overrepresentation of aryl hydrocarbon receptor response elements in regions bound by both AHR and ERalpha, suggesting that AHR was the important factor determining the recruitment of ERalpha to these regions. RNA interference-mediated knockdown of AHR confirmed its requirement for the recruitment of ERalpha to some, but not all, of the shared regions. Our findings demonstrate not only that dioxin induces the recruitment of ERalpha to AHR target genes but also that AHR is recruited to estrogen-responsive regions in a gene-specific manner, suggesting that AHR utilizes both of these mechanisms to modulate estrogen-dependent signaling.
Collapse
Affiliation(s)
- Shaimaa Ahmed
- Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | | | | | | |
Collapse
|
35
|
Androutsopoulos VP, Tsatsakis AM, Spandidos DA. Cytochrome P450 CYP1A1: wider roles in cancer progression and prevention. BMC Cancer 2009; 9:187. [PMID: 19531241 PMCID: PMC2703651 DOI: 10.1186/1471-2407-9-187] [Citation(s) in RCA: 287] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Accepted: 06/16/2009] [Indexed: 02/08/2023] Open
Abstract
CYP1A1 is one of the main cytochrome P450 enzymes, examined extensively for its capacity to activate compounds with carcinogenic properties. Continuous exposure to inhalation chemicals and environmental carcinogens is thought to increase the level of CYP1A1 expression in extrahepatic tissues, through the aryl hydrocarbon receptor (AhR). Although the latter has long been recognized as a ligand-induced transcription factor, which is responsible for the xenobiotic activating pathway of several phase I and phase II metabolizing enzymes, recent evidence suggests that the AhR is involved in various cell signaling pathways critical to cell cycle regulation and normal homeostasis. Disregulation of these pathways is implicated in tumor progression. In addition, it is becoming increasingly evident that CYP1A1 plays an important role in the detoxication of environmental carcinogens, as well as in the metabolic activation of dietary compounds with cancer preventative activity. Ultimately the contribution of CYP1A1 to cancer progression or prevention may depend on the balance of procarcinogen activation/detoxication and dietary natural product extrahepatic metabolism.
Collapse
Affiliation(s)
- Vasilis P Androutsopoulos
- Department of Medicine, Division of Forensic Sciences and Toxicology, University of Crete, Crete, Greece.
| | | | | |
Collapse
|
36
|
Ma C, Marlowe JL, Puga A. The aryl hydrocarbon receptor at the crossroads of multiple signaling pathways. EXS 2009; 99:231-57. [PMID: 19157064 DOI: 10.1007/978-3-7643-8336-7_9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The aryl hydrocarbon receptor (AHR) has long been recognized as a ligand-activated transcription factor responsible for the induction of drug-metabolizing enzymes. Its role in the combinatorial matrix of cell functions was established long before the first report of an AHR cDNA sequence was published. It is only recently that other functions of this protein have begun to be recognized, and it is now clear that the AHR also functions in pathways outside of its well-characterized role in xenobiotic enzyme induction. Perturbation of these pathways by xenobiotic ligands may ultimately explain much of the toxicity of these compounds. This chapter focuses on the interactions of the AHR in pathways critical to cell cycle regulation, mitogen-activated protein kinase cascades, differentiation and apoptosis. Ultimately, the effect of a particular AHR ligand on the biology of the organism will depend on the milieu of critical pathways and proteins expressed in specific cells and tissues with which the AHR itself interacts.
Collapse
Affiliation(s)
- Ci Ma
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, OH 45220, USA.
| | | | | |
Collapse
|
37
|
Ghose R, Guo T, Haque N. Regulation of gene expression of hepatic drug metabolizing enzymes and transporters by the Toll-like receptor 2 ligand, lipoteichoic acid. Arch Biochem Biophys 2008; 481:123-30. [PMID: 18940178 DOI: 10.1016/j.abb.2008.10.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2008] [Revised: 09/29/2008] [Accepted: 10/06/2008] [Indexed: 01/07/2023]
Abstract
Expression of hepatic drug metabolizing enzymes (DMEs) is altered in infection and inflammation. However, the role of Gram+ve bacterial components and their receptor, Toll-like receptor (TLR) 2 in regulation of hepatic DMEs is unknown. Gene expression of DMEs is regulated by members of the nuclear receptor superfamily (PXR, CAR and RXRalpha). The TLR2 ligand, lipoteichoic acid (LTA) reduced RNA levels of CAR and its target genes, Cyp2b10, Cyp2a4 and Sultn in mouse liver ( approximately 60-80% reduction). Hepatic genes regulated by PXR and CAR, Cyp3a11 and Mrp2 were moderately reduced by LTA, along with approximately 50% reduction of PXR RNA and nuclear protein levels of RXRalpha. The effects of LTA were significantly attenuated by pre-treatment with the Kupffer cell inhibitor, gadolinium chloride, indicating that Kupffer cells contribute to LTA-mediated down-regulation of hepatic genes. These results indicate that treatment with Gram+ve bacterial components preferentially down-regulate CAR and its target genes in the liver.
Collapse
Affiliation(s)
- Romi Ghose
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, 1441 Moursund Street, Houston, TX 77030, USA.
| | | | | |
Collapse
|
38
|
Garside H, Stewart A, Brown N, Cooke EL, Graham M, Sullivan M. Quantitative analysis of aryl hydrocarbon receptor activation using fluorescence-based cell imaging—A high-throughput mechanism-based assay for drug discovery. Xenobiotica 2008; 38:1-20. [DOI: 10.1080/00498250701668600] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
39
|
Puga A, Ma C, Marlowe JL. The aryl hydrocarbon receptor cross-talks with multiple signal transduction pathways. Biochem Pharmacol 2008; 77:713-22. [PMID: 18817753 DOI: 10.1016/j.bcp.2008.08.031] [Citation(s) in RCA: 288] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Revised: 08/20/2008] [Accepted: 08/21/2008] [Indexed: 12/13/2022]
Abstract
Exposure to toxic polycyclic aromatic hydrocarbons raises a number of toxic and carcinogenic responses in experimental animals and humans mediated for the most part by the aryl hydrocarbon -- or dioxin -- receptor (AHR). The AHR is a ligand-activated transcription factor whose central role in the induction of drug-metabolizing enzymes has long been recognized. For quite some time now, it has become clear that the AHR also functions in pathways outside of its role in detoxification and that perturbation of these pathways by xenobiotic ligands may be an important part of the toxicity of these compounds. AHR activation by some of its ligands participates among others in pathways critical to cell cycle regulation, mitogen-activated protein kinase cascades, immediate-early gene induction, cross-talk within the RB/E2F axis and mobilization of crucial calcium stores. Ultimately, the effect of a particular AHR ligand may depend as much on the adaptive interactions that it established with pathways and proteins expressed in a specific cell or tissue as on the toxic responses that it raises.
Collapse
Affiliation(s)
- Alvaro Puga
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, OH 45220, USA.
| | | | | |
Collapse
|
40
|
Interaction between the aryl hydrocarbon receptor and transforming growth factor-beta signaling pathways: evidence of an asymmetrical relationship in rat granulosa cells. Biochem Pharmacol 2008; 76:1165-74. [PMID: 18786509 DOI: 10.1016/j.bcp.2008.08.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Revised: 08/09/2008] [Accepted: 08/14/2008] [Indexed: 12/30/2022]
Abstract
The aryl hydrocarbon receptor (AHR) mediates toxic responses to environmental contaminants and plays pivotal physiological roles in various biological processes as well, particularly in ovarian function. It is well documented that expression and function of the AHR is negatively regulated by transforming growth factor-beta (TGF-beta) in many cell types. In addition, several studies indicate that AHR activity inhibits TGF-beta expression and function in some systems. However, the interplay between these two signals is highly dependent upon the cell type being studied, precluding a generalization about the outcome of such interaction. Therefore, the goal of the present study was to determine the effect of TGF-beta on AHR expression and activation in granulosa cells, an ovarian cell type where the growth factor is mitogenic and AHR activation has been associated with promotion of proliferation as well. In addition, we conducted experiments aimed at evaluating the effect of AHR ligands on TGF-beta action in our system. Results presented herein demonstrate that AHR expression is not regulated by TGF-beta in rat granulosa cells, neither at the mRNA level nor at the protein level. Moreover, we find that the growth factor does not alter the transcriptional function of the AHR. Conversely, we show that activation of AHR by an agonist deregulates TGF-beta function in granulosa cells, inhibiting its transcriptional activity and its mitogenic action. The described one-sided interplay between TGF-beta and AHR signaling pathway may help provide a mechanistic explanation to some of the physiological outcomes of AHR or TGF-beta activation in granulosa cells.
Collapse
|
41
|
Korashy HM, El-Kadi AOS. NF-κB and AP-1 are key signaling pathways in the modulation of NAD(P)H:Quinone oxidoreductase 1 gene by mercury, lead, and copper. J Biochem Mol Toxicol 2008; 22:274-83. [DOI: 10.1002/jbt.20238] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
42
|
Microtubules-interfering agents restrict aryl hydrocarbon receptor-mediated CYP1A2 induction in primary cultures of human hepatocytes via c-jun-N-terminal kinase and glucocorticoid receptor. Eur J Pharmacol 2008; 581:244-54. [DOI: 10.1016/j.ejphar.2007.11.059] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2007] [Revised: 10/24/2007] [Accepted: 11/14/2007] [Indexed: 11/19/2022]
|
43
|
Korashy HM, El-Kadi AOS. The role of redox-sensitive transcription factors NF-kappaB and AP-1 in the modulation of the Cyp1a1 gene by mercury, lead, and copper. Free Radic Biol Med 2008; 44:795-806. [PMID: 18078826 DOI: 10.1016/j.freeradbiomed.2007.11.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2007] [Revised: 11/02/2007] [Accepted: 11/05/2007] [Indexed: 02/06/2023]
Abstract
We have previously shown that Hg(2+), Pb(2+), and Cu(2+) significantly induced the expression of Cyp1a1 mRNA, but the catalytic activity was inhibited by the three metals, and the inhibition was accompanied by an increase in the oxidative stress status. In the current study we investigated the role of redox-sensitive transcription factors and the NF-kappaB and AP-1 signaling pathways in the metal-mediated effects on Cyp1a1 gene expression. We show that heavy metals caused the induction of oxidative stress markers, such as reactive oxygen species and heme oxygenase-1, and the depletion of cellular glutathione content, which was associated with NF-kappaB and AP-1 activation. In addition, the NF-kappaB activator PMA significantly abolished the metal-mediated induction of Cyp1a1 mRNA, whereas it further potentiated their inhibitory effects on Cyp1a1 activity. In parallel, the NF-kappaB inhibitor PDTC further potentiated the metal-mediated induction of Cyp1a1 mRNA, whereas it reversed their inhibitory effects on Cyp1a1 activity. Inhibition of AP-1 upstream signaling pathway activators such as JNK by SP600125 suppressed Cyp1a1 mRNA induction by heavy metals, whereas it potentiated their inhibitory effects at the activity level. In contrast, the ERK inhibitor U0126 further potentiated heavy metal-mediated induction of Cyp1a1 mRNA, whereas it reversed their inhibitory effects on the Cyp1a1 activity. The p38 MAPK inhibitor SB203580 suppressed the metal-mediated induction of Cyp1a1 mRNA, but did not alter Cyp1a1 activity. These results clearly demonstrate that activation of the NF-kappaB and AP-1 signaling pathways is directly involved in the modulation of Cyp1a1 by heavy metals.
Collapse
Affiliation(s)
- Hesham M Korashy
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta, Canada
| | | |
Collapse
|
44
|
Alonso M, Casado S, Miranda C, Tarazona JV, Navas JM, Herradón B. Decabromobiphenyl (PBB-209) activates the aryl hydrocarbon receptor while decachlorobiphenyl (PCB-209) is inactive: experimental evidence and computational rationalization of the different behavior of some halogenated biphenyls. Chem Res Toxicol 2008; 21:643-58. [PMID: 18311929 DOI: 10.1021/tx700362u] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In rat H4IIE cells permanently transfected with a luciferase gene under the control of AhR, incubation with PBB-209 led to a statistically significant increase of luminescence. In this system, PCB-209 only caused a small induction of luciferase activity. In a fish cell line, only PBB-209 was able to provoke an induction of ethoxyresorufin- O-deethylase activity. Ligand binding to the AhR was studied by means of a cell-free in vitro system in which the activation of AhR is very unlikely to occur without ligand binding. None of the biphenyls studied provoked any activation of AhR in this system. To rationalize the results and to get insight into the molecular mechanism of activation of AhR by PBB-209 as compared with PCB-209, a comprehensive computational study was carried out on these congeners as well as on PCB-126 and PCB-169, two potent AhR activators through ligand binding. The calculations include (i) conformational analysis and dipole moments of each conformer, (ii) aromaticity indices, (iii) molecular electrostatic potentials, (iv) quadrupole moments, (v) electronic and reactivity descriptors, and (vi) dissociation energies of C-Cl and C-Br bonds in model aromatic compounds. It was found that some molecular features of PBB-209, such as the electrostatic potential (EP) and EP-derived descriptors (Politzer's parameters), indicate that PBB-209 is more similar to PCB-126 and PCB-169 than to PCB-209, which share quite similar geometries based on the substitution pattern. The similarity between PBB-209, PCB-126, and PCB-169 seems to hint that these three compounds can share, at least partially, similar mechanisms of activation of AhR. It is unquestionable that PCB-126 and PCB-169 directly bind AhR and PBB-209 does not. We hypothesize that there are several simultaneous mechanisms for activation of AhR, and the most active compounds act for more than one mechanism.
Collapse
Affiliation(s)
- Mercedes Alonso
- Instituto de Química Orgánica General, CSIC, Juan de la Cierva 3, E-28006 Madrid, Spain
| | | | | | | | | | | |
Collapse
|
45
|
Fiorito F, Pagnini U, De Martino L, Montagnaro S, Ciarcia R, Florio S, Pacilio M, Fucito A, Rossi A, Iovane G, Giordano A. 2,3,7,8-Tetrachlorodibenzo-p-dioxin increases Bovine Herpesvirus type-1 (BHV-1) replication in Madin-Darby Bovine Kidney (MDBK) cells in vitro. J Cell Biochem 2008; 103:221-33. [PMID: 17516555 DOI: 10.1002/jcb.21398] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Dioxin-2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a common environmental toxin of current interest. In the last years, higher levels of TCDD than those permitted in UE [European Commission. 2002. European Commission Recommendation 2002/201/CE. Official Gazette, L 67/69] were detected in milk samples from cow, water buffalo, goat, and sheep raised on some areas of Campania Region (South Italy). Dioxin often causes immunosuppression and might render the animal liable to viral infections. In addition, viral infections are able to alter the pattern of dioxin distribution in different organs of the exposed animals. Bovine Herpesvirus type-1 (BHV-1) is a widespread pathogen, which causes infectious rhinotracheitis and infectious pustular vulvovaginitis in cattle. Herein, we have studied the effects of TCDD and BHV-1 infection, in Madin-Darby Bovine Kidney (MDBK) cells, alone as well as in association, so as cellular proliferation, apoptosis, and virus replication. We have observed an increase in cell viability of confluent monolayers at low TCDD concentrations. TCDD treated cells demonstrated increased viability compared to controls as evaluated by MTT test. TCDD exposure increased cell proliferation but induced no changes on apoptosis. Cells exposed to TCDD along with BHV-1 showed a dose-dependent increase in cytopathy, represented by ample syncytia formation with the elimination of the cellular sheets and increased viral titer. These results suggest that TCDD increases viral replication in MDBK cells while BHV-1 further decreases viability of TCDD exposed cells. Since very low concentrations (0.01 pg/ml) are sufficient to augment BHV-1 titer, TCDD may contribute to reactivate BHV-1 from latency, leading to recurrent disease and increase virus transmission.
Collapse
Affiliation(s)
- F Fiorito
- Department of Pathology and Animal Health, Naples, Italy
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
46
|
Saracino MR, Lampe JW. Phytochemical regulation of UDP-glucuronosyltransferases: implications for cancer prevention. Nutr Cancer 2008; 59:121-41. [PMID: 18001207 DOI: 10.1080/01635580701458178] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Uridine 5'-diphospho-glucuronosyltransferases (UGTs) are Phase II biotransformation enzymes that metabolize endogenous and exogenous compounds, some of which have been associated with cancer risk. Many phytochemicals have been shown to induce UGTs in humans, rodents, and cell culture systems. Because UGTs maintain hormone balance and facilitate excretion of potentially carcinogenic compounds, regulation of their expression and activity may affect cancer risk. Phytochemicals regulate transcription factors such as the nuclear factor-erythroid 2-related factor 2 (Nrf2), aryl hydrocarbon, and pregnane X receptors as well as proteins in several signal transduction cascades that converge on Nrf2 to stimulate UGT expression. This induction can be modified by several factors, including phytochemical dose and bioavailability and interindividual variation in enzyme expression. In this review, we summarize the knowledge of dietary modulation of UGTs, particularly by phytochemicals, and discuss the potential mechanisms by which phytochemicals regulate UGT transcription.
Collapse
|
47
|
Dvorak Z, Vrzal R, Henklova P, Jancova P, Anzenbacherova E, Maurel P, Svecova L, Pavek P, Ehrmann J, Havlik R, Bednar P, Lemr K, Ulrichova J. JNK inhibitor SP600125 is a partial agonist of human aryl hydrocarbon receptor and induces CYP1A1 and CYP1A2 genes in primary human hepatocytes. Biochem Pharmacol 2008; 75:580-8. [DOI: 10.1016/j.bcp.2007.09.013] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2007] [Revised: 09/05/2007] [Accepted: 09/05/2007] [Indexed: 10/22/2022]
|
48
|
Henklová P, Vrzal R, Ulrichová J, Dvorák Z. Role of mitogen-activated protein kinases in aryl hydrocarbon receptor signaling. Chem Biol Interact 2007; 172:93-104. [PMID: 18282562 DOI: 10.1016/j.cbi.2007.12.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2007] [Revised: 12/14/2007] [Accepted: 12/19/2007] [Indexed: 10/22/2022]
Abstract
Human populations are increasingly exposed to a number of environmental pollutants such as polycyclic aromatic hydrocarbons, polychlorinated biphenyls and dioxins. These compounds are activators of the aryl hydrocarbon receptor (AhR) that controls the expression of many genes including those for detoxification enzymes. The regulatory mechanisms of AhR are multi-factorial and include phosphorylation by various protein kinases. Significant progress in the research of mitogen-activated protein kinases (MAPKs) has been achieved in the last decade. Isolated reports have been published on the role of MAPKs in AhR functions and vice versa, with activation of MAPKs by AhR ligands. This mini-review summarizes current knowledge on the mutual interactions between MAPKs and AhR. The majority of studies has been done on cancer-derived cell lines that have impaired cell cycle regulation and lacks the complete detoxification apparatus. We emphasize the importance of the future studies that should be done on non-transformed cells to distinguish the role of MAPKs in cancer and normal cells. Primary cultures of human or rodent hepatocytes that are equipped with a fully functional biotransformation battery or xenobiotics-metabolizing extra-hepatic tissues should be the models of choice, as the results in our experiments confirm.
Collapse
Affiliation(s)
- Pavla Henklová
- Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry, Palacky University, Hnevotínská 3, 775 15 Olomouc, Czech Republic
| | | | | | | |
Collapse
|
49
|
Monteiro P, Gilot D, Le Ferrec E, Rauch C, Lagadic-Gossmann D, Fardel O. Dioxin-Mediated Up-Regulation of Aryl Hydrocarbon Receptor Target Genes Is Dependent on the Calcium/Calmodulin/CaMKIα Pathway. Mol Pharmacol 2007; 73:769-77. [DOI: 10.1124/mol.107.043125] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|
50
|
Han Z, Miwa Y, Obikane H, Mitsumata M, Takahashi-Yanaga F, Morimoto S, Sasaguri T. Aryl hydrocarbon receptor mediates laminar fluid shear stress-induced CYP1A1 activation and cell cycle arrest in vascular endothelial cells. Cardiovasc Res 2007; 77:809-18. [PMID: 18065768 DOI: 10.1093/cvr/cvm095] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
AIMS We investigated the mechanisms of shear stress (SS)-induced activation of cytochrome P450 (CYP) 1A1 and cell cycle arrest with regard to the role of the aryl hydrocarbon receptor (AhR), since AhR mediates the expression of CYP1A1 induced by polycyclic aromatic hydrocarbons (PAHs) and is thought to be involved in the regulation of cell growth and differentiation. METHODS AND RESULTS Human umbilical vein endothelial cells (ECs) were exposed to laminar SS and thereafter collected to evaluate the expression, activity, and transcription of CYP1A1 and the expression of AhR and cell cycle-related proteins. A physiological level of laminar SS (15 dynes/cm(2)) markedly increased the expression level and enzymatic activity of CYP1A1. SS stimulated CYP1A1 promoter activity without influencing mRNA stability. Loss of two functional xenobiotic response elements (XREs) in the 5'-flanking region of the CYP1A1 gene suppressed the SS-induced transcription of CYP1A1. Laminar SS stimulated the expression and nuclear translocation of AhR. alpha-Naphthoflavone, an AhR antagonist, and a small interfering RNA (siRNA) for AhR significantly suppressed SS-induced CYP1A1 expression. The siRNA also abolished SS-induced cell cycle arrest, the expression of the cyclin-dependent kinase inhibitor p21(Cip1), and dephosphorylation of retinoblastoma protein. CONCLUSION Laminar SS stimulated the transcription of CYP1A1 through the activation of AhR in a way that is similar to the effects of PAHs. AhR was also involved in cell cycle arrest induced by SS. Our results suggest that sustained activation of AhR exposed to blood flow plays an important role in the regulation of EC functions.
Collapse
Affiliation(s)
- Zhiyi Han
- Department of Clinical Pharmacology, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan
| | | | | | | | | | | | | |
Collapse
|