1
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Zhang R, Yu C, Zeh HJ, Wang H, Kroemer G, Klionsky DJ, Billiar TR, Kang R, Tang D. Nuclear localization of STING1 competes with canonical signaling to activate AHR for commensal and intestinal homeostasis. Immunity 2023; 56:2736-2754.e8. [PMID: 38016467 PMCID: PMC10842782 DOI: 10.1016/j.immuni.2023.11.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 09/22/2023] [Accepted: 11/01/2023] [Indexed: 11/30/2023]
Abstract
Extensive studies demonstrate the importance of the STING1 (also known as STING) protein as a signaling hub that coordinates immune and autophagic responses to ectopic DNA in the cytoplasm. Here, we report a nuclear function of STING1 in driving the activation of the transcription factor aryl hydrocarbon receptor (AHR) to control gut microbiota composition and homeostasis. This function was independent of DNA sensing and autophagy and showed competitive inhibition with cytoplasmic cyclic guanosine monophosphate (GMP)-AMP synthase (CGAS)-STING1 signaling. Structurally, the cyclic dinucleotide binding domain of STING1 interacted with the AHR N-terminal domain. Proteomic analyses revealed that STING1-mediated transcriptional activation of AHR required additional nuclear partners, including positive and negative regulatory proteins. Although AHR ligands could rescue colitis pathology and dysbiosis in wild-type mice, this protection was abrogated by mutational inactivation of STING1. These findings establish a key framework for understanding the nuclear molecular crosstalk between the microbiota and the immune system.
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Affiliation(s)
- Ruoxi Zhang
- Department of Surgery, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Chunhua Yu
- Department of Surgery, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Herbert J Zeh
- Department of Surgery, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Haichao Wang
- Laboratory of Emergency Medicine, North Shore University Hospital and the Feinsteins Institute for Medical Research, Manhasset, NY 11030, USA
| | - Guido Kroemer
- Centre de Recherche des Cordeliers, Equipe labellisée par la Ligue contre le cancer, Université de Paris, Sorbonne Université, INSERM U1138, Institut Universitaire de France, Paris, France; Metabolomics and Cell Biology Platforms, Gustave Roussy Cancer Campus, 94800 Villejuif, France; Pôle de Biologie, Hôpital Européen Georges Pompidou, AP-HP, 75015 Paris, France
| | - Daniel J Klionsky
- Life Sciences Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Timothy R Billiar
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Rui Kang
- Department of Surgery, UT Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Daolin Tang
- Department of Surgery, UT Southwestern Medical Center, Dallas, TX 75390, USA.
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2
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Piwarski SA, Salisbury TB. The effects of environmental aryl hydrocarbon receptor ligands on signaling and cell metabolism in cancer. Biochem Pharmacol 2023; 216:115771. [PMID: 37652105 DOI: 10.1016/j.bcp.2023.115771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 08/18/2023] [Accepted: 08/28/2023] [Indexed: 09/02/2023]
Abstract
Dioxin and dioxin-like compounds are chlorinated organic pollutants formed during the manufacturing of other chemicals. Dioxins are ligands of the aryl hydrocarbon receptor (AHR), that induce AHR-mediated biochemical and toxic responses and are persistent in the environment. 2,3,7,8- tetrachlorodibenzo para dioxin (TCDD) is the prototypical AHR ligand and its effects represent dioxins. TCDD induces toxicity, immunosuppression and is a suspected tumor promoter. The role of TCDD in cancer however is debated and context-dependent. Environmental particulate matter, polycyclic aromatic hydrocarbons, perfluorooctane sulfonamide, endogenous AHR ligands, and cAMP signaling activate AHR through TCDD-independent pathways. The effect of activated AHR in cancer is context-dependent. The ability of FDA-approved drugs to modulate AHR activity has sparked interest in their repurposing for cancer therapy. TCDD by interfering with endogenous pathways, and overstimulating other endogenous pathways influences all stages of cancer. Herein we review signaling mechanisms that activate AHR and mechanisms by which activated AHR modulates signaling in cancer including affected metabolic pathways.
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Affiliation(s)
- Sean A Piwarski
- Duke Cancer Institute, Department of GU Oncology, Duke University Medical Center, 905 South Lasalle Street, Durham, NC 27710, USA.
| | - Travis B Salisbury
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, 1 John Marshall Drive, Huntington, WV 25755, USA.
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3
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Chong ZX, Yong CY, Ong AHK, Yeap SK, Ho WY. Deciphering the roles of aryl hydrocarbon receptor (AHR) in regulating carcinogenesis. Toxicology 2023; 495:153596. [PMID: 37480978 DOI: 10.1016/j.tox.2023.153596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 07/13/2023] [Accepted: 07/16/2023] [Indexed: 07/24/2023]
Abstract
Aryl hydrocarbon receptor (AHR) is a ligand-dependent receptor that belongs to the superfamily of basic helix-loop-helix (bHLH) transcription factors. The activation of the canonical AHR signaling pathway is known to induce the expression of cytochrome P450 enzymes, facilitating the detoxification metabolism in the human body. Additionally, AHR could interact with various signaling pathways such as epidermal growth factor receptor (EGFR), signal transducer and activator of transcription 3 (STAT3), hypoxia-inducible factor-1α (HIF-1α), nuclear factor ekappa B (NF-κβ), estrogen receptor (ER), and androgen receptor (AR) signaling pathways. Over the past 30 years, several studies have reported that various chemical, physical, or biological agents, such as tobacco, hydrocarbon compounds, industrial and agricultural chemical wastes, drugs, UV, viruses, and other toxins, could affect AHR expression or activity, promoting cancer development. Thus, it is valuable to overview how these factors regulate AHR-mediated carcinogenesis. Current findings have reported that many compounds could act as AHR ligands to drive the expressions of AHR-target genes, such as CYP1A1, CYP1B1, MMPs, and AXL, and other targets that exert a pro-proliferation or anti-apoptotic effect, like XIAP. Furthermore, some other physical and chemical agents, such as UV and 3-methylcholanthrene, could promote AHR signaling activities, increasing the signaling activities of a few oncogenic pathways, such as the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) and mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) pathways. Understanding how various factors regulate AHR-mediated carcinogenesis processes helps clinicians and scientists plan personalized therapeutic strategies to improve anti-cancer treatment efficacy. As many studies that have reported the roles of AHR in regulating carcinogenesis are preclinical or observational clinical studies that did not explore the detailed mechanisms of how different chemical, physical, or biological agents promote AHR-mediated carcinogenesis processes, future studies should focus on conducting large-scale and functional studies to unravel the underlying mechanism of how AHR interacts with different factors in regulating carcinogenesis processes.
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Affiliation(s)
- Zhi Xiong Chong
- Faculty of Science and Engineering, University of Nottingham Malaysia, 43500 Semenyih, Selangor, Malaysia
| | - Chean Yeah Yong
- China-ASEAN College of Marine Sciences, Xiamen University Malaysia, 43900 Sepang, Selangor, Malaysia
| | - Alan Han Kiat Ong
- Faculty of Medicine and Health Sciences, Universiti Tunku Abdul Rahman, 43000 Kajang, Malaysia
| | - Swee Keong Yeap
- China-ASEAN College of Marine Sciences, Xiamen University Malaysia, 43900 Sepang, Selangor, Malaysia.
| | - Wan Yong Ho
- Faculty of Science and Engineering, University of Nottingham Malaysia, 43500 Semenyih, Selangor, Malaysia.
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4
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Salminen A. Mutual antagonism between aryl hydrocarbon receptor and hypoxia-inducible factor-1α (AhR/HIF-1α) signaling: Impact on the aging process. Cell Signal 2022; 99:110445. [PMID: 35988806 DOI: 10.1016/j.cellsig.2022.110445] [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: 06/20/2022] [Revised: 07/27/2022] [Accepted: 08/16/2022] [Indexed: 11/26/2022]
Abstract
The ambient oxygen level, many environmental toxins, and the rays of ultraviolet light (UV) provide a significant risk for the maintenance of organismal homeostasis. The aryl hydrocarbon receptors (AhR) represent a complex sensor system not only for environmental toxins and UV radiation but also for many endogenous ligands, e.g., L-tryptophan metabolites. The AhR signaling system is evolutionarily conserved and AhR homologs existed as many as 600 million years ago. The ancient atmosphere demanded the evolution of an oxygen-sensing system, i.e., hypoxia-inducible transcription factors (HIF) and their prolyl hydroxylase regulators (PHD). Given that both signaling systems have important roles in embryogenesis, it seems that they have been involved in the evolution of multicellular organisms. The evolutionary origin of the aging process is unknown although it is most likely associated with the evolution of multicellularity. Intriguingly, there is compelling evidence that while HIF-1α signaling extends the lifespan, that of AhR promotes many age-related degenerative processes, e.g., it increases oxidative stress, inhibits autophagy, promotes cellular senescence, and aggravates extracellular matrix degeneration. In contrast, HIF-1α signaling stimulates autophagy, inhibits cellular senescence, and enhances cell proliferation. Interestingly, there is a clear antagonism between the AhR and HIF-1α signaling pathways. For instance, (i) AhR and HIF-1α factors heterodimerize with the same factor, ARNT/HIF-1β, leading to their competition for DNA-binding, (ii) AhR and HIF-1α signaling exert antagonistic effects on autophagy, and (iii) co-chaperone p23 exhibits specific functions in the signaling of AhR and HIF-1α factors. One might speculate that it is the competition between the AhR and HIF-1α signaling pathways that is a driving force in the aging process.
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Affiliation(s)
- Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland.
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5
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Edwards HE, Gorelick DA. The evolution and structure/function of bHLH-PAS transcription factor family. Biochem Soc Trans 2022; 50:1227-1243. [PMID: 35695677 PMCID: PMC10584024 DOI: 10.1042/bst20211225] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 05/23/2022] [Accepted: 05/24/2022] [Indexed: 02/06/2023]
Abstract
Proteins that contain basic helix-loop-helix (bHLH) and Per-Arnt-Sim motifs (PAS) function as transcription factors. bHLH-PAS proteins exhibit essential and diverse functions throughout the body, from cell specification and differentiation in embryonic development to the proper function of organs like the brain and liver in adulthood. bHLH-PAS proteins are divided into two classes, which form heterodimers to regulate transcription. Class I bHLH-PAS proteins are typically activated in response to specific stimuli, while class II proteins are expressed more ubiquitously. Here, we discuss the general structure and functions of bHLH-PAS proteins throughout the animal kingdom, including family members that do not fit neatly into the class I-class II organization. We review heterodimerization between class I and class II bHLH-PAS proteins, binding partner selectivity and functional redundancy. Finally, we discuss the evolution of bHLH-PAS proteins, and why a class I protein essential for cardiovascular development in vertebrates like chicken and fish is absent from mammals.
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Affiliation(s)
- Hailey E Edwards
- Center for Precision Environmental Health, Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, U.S.A
| | - Daniel A Gorelick
- Center for Precision Environmental Health, Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, U.S.A
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6
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The role of DNA-binding and ARNT dimerization on the nucleo-cytoplasmic translocation of the aryl hydrocarbon receptor. Sci Rep 2021; 11:18194. [PMID: 34521881 PMCID: PMC8440571 DOI: 10.1038/s41598-021-97507-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 08/24/2021] [Indexed: 01/19/2023] Open
Abstract
The human aryl hydrocarbon receptor (AHR) is predominantly located in the cytoplasm, while activation depends on its nuclear translocation. Binding to endogenous or xenobiotic ligands terminates the basal nucleo-cytoplasmic shuttling and stabilizes an exclusive nuclear population. The precise mechanisms that facilitate such stable nuclear accumulation remain to be clarified as essential step in the activation cascade. In this study, we have tested whether the sustained nuclear compartmentalization of ligand-bound or basal AHR might further require heterodimerization with the AHR-nuclear translocator (ARNT) and binding to the cognate XRE-motif. Mutagenesis of the DNA-binding motif or of selected individual residues in the ARNT-binding motif did not lead to any variation in AHR’s nucleo-cytoplasmic distribution. In response to ligands, all mutants were retained in the nucleus demonstrating that the stable compartmentalization of activated AHR in the nucleus is neither dependent on interactions with DNA, nor ARNT. Knocking down the ARNT gene using small interfering RNA confirmed that ARNT does not play any role in the intracellular trafficking of AHR.
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7
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Tarczewska A, Greb-Markiewicz B. The Significance of the Intrinsically Disordered Regions for the Functions of the bHLH Transcription Factors. Int J Mol Sci 2019; 20:E5306. [PMID: 31653121 PMCID: PMC6862971 DOI: 10.3390/ijms20215306] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 10/22/2019] [Accepted: 10/22/2019] [Indexed: 11/17/2022] Open
Abstract
The bHLH proteins are a family of eukaryotic transcription factors regulating expression of a wide range of genes involved in cell differentiation and development. They contain the Helix-Loop-Helix (HLH) domain, preceded by a stretch of basic residues, which are responsible for dimerization and binding to E-box sequences. In addition to the well-preserved DNA-binding bHLH domain, these proteins may contain various additional domains determining the specificity of performed transcriptional regulation. According to this, the family has been divided into distinct classes. Our aim was to emphasize the significance of existing disordered regions within the bHLH transcription factors for their functionality. Flexible, intrinsically disordered regions containing various motives and specific sequences allow for multiple interactions with transcription co-regulators. Also, based on in silico analysis and previous studies, we hypothesize that the bHLH proteins have a general ability to undergo spontaneous phase separation, forming or participating into liquid condensates which constitute functional centers involved in transcription regulation. We shortly introduce recent findings on the crucial role of the thermodynamically liquid-liquid driven phase separation in transcription regulation by disordered regions of regulatory proteins. We believe that further experimental studies should be performed in this field for better understanding of the mechanism of gene expression regulation (among others regarding oncogenes) by important and linked to many diseases the bHLH transcription factors.
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Affiliation(s)
- Aneta Tarczewska
- Department of Biochemistry, Faculty of Chemistry, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland.
| | - Beata Greb-Markiewicz
- Department of Biochemistry, Faculty of Chemistry, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland.
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8
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Al-Ghezi ZZ, Singh N, Mehrpouya-Bahrami P, Busbee PB, Nagarkatti M, Nagarkatti PS. AhR Activation by TCDD (2,3,7,8-Tetrachlorodibenzo-p-dioxin) Attenuates Pertussis Toxin-Induced Inflammatory Responses by Differential Regulation of Tregs and Th17 Cells Through Specific Targeting by microRNA. Front Microbiol 2019; 10:2349. [PMID: 31681214 PMCID: PMC6813193 DOI: 10.3389/fmicb.2019.02349] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 09/26/2019] [Indexed: 12/14/2022] Open
Abstract
The Aryl Hydrocarbon Receptor (AhR) is a transcription factor that, when activated by ligand-binding, has been shown to regulate the immune response. Pertussis Toxin (PTX) is a virulence factor found in Bordetella pertussis, a human respiratory pathogen that causes whooping cough. PTX promotes colonization and disease promotion by triggering a heightened inflammatory response. The role of AhR in the regulation of PTX-mediated inflammation has not previously been studied. In the current study, we investigate if AhR activation by 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), a well characterized ligand, can attenuate PTX-mediated systemic inflammation. To that end, C57BL/6 mice were injected intraperitoneally (IP) with PTX twice and treated with TCDD or vehicle (VEH). The PTX+VEH group showed elevated levels of pro-inflammatory cytokines (IL-17A, IL-6, and IFNγ) in serum and increased proportions of CD4+ Th1 and Th17 cells in their spleens. In contrast, the PTX+TCDD group showed significantly lower levels of these inflammatory cytokines and decreased proportions of Th1 and Th17 cells, but increased proportions of Th2 and FoxP3+Tregs when compared to the PTX+VEH group. PTX+TCDD treated mice also showed elevated levels of IL-10, and TFG-b, potent anti-inflammatory cytokines. MicroRNAs (miRs) analysis of CD4+ T cells from the spleens of the PTX+TCDD treated mice revealed significant alterations in their expression and several of these miRs targeted cytokines and signaling molecules involved in inflammation. Specifically, the PTX+TCDD group had a significantly enhanced expression of miR-3082-5p that targeted IL-17, and a decreased expression of miR-1224-5p, which targeted FoxP3. Transfection studies with these miR mimics and inhibitors confirmed the specificity of the target genes. The current study suggests that AhR activation by TCDD suppresses PTX-induced inflammation through miR regulation that triggers reciprocal polarization of Tregs and Th17 cells and also suggests that AhR activation may serve as a treatment modality to suppress heightened inflammation induced during B. pertussis infection.
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Affiliation(s)
- Zinah Zamil Al-Ghezi
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC, United States
| | - Narendra Singh
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC, United States
| | - Pegah Mehrpouya-Bahrami
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC, United States
| | - Philip Brandon Busbee
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC, United States
| | - Mitzi Nagarkatti
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC, United States
| | - Prakash S Nagarkatti
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC, United States
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9
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Kolonko M, Greb-Markiewicz B. bHLH-PAS Proteins: Their Structure and Intrinsic Disorder. Int J Mol Sci 2019; 20:ijms20153653. [PMID: 31357385 PMCID: PMC6695611 DOI: 10.3390/ijms20153653] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 07/15/2019] [Accepted: 07/16/2019] [Indexed: 12/21/2022] Open
Abstract
The basic helix–loop–helix/Per-ARNT-SIM (bHLH–PAS) proteins are a class of transcriptional regulators, commonly occurring in living organisms and highly conserved among vertebrates and invertebrates. These proteins exhibit a relatively well-conserved domain structure: the bHLH domain located at the N-terminus, followed by PAS-A and PAS-B domains. In contrast, their C-terminal fragments present significant variability in their primary structure and are unique for individual proteins. C-termini were shown to be responsible for the specific modulation of protein action. In this review, we present the current state of knowledge, based on NMR and X-ray analysis, concerning the structural properties of bHLH–PAS proteins. It is worth noting that all determined structures comprise only selected domains (bHLH and/or PAS). At the same time, substantial parts of proteins, comprising their long C-termini, have not been structurally characterized to date. Interestingly, these regions appear to be intrinsically disordered (IDRs) and are still a challenge to research. We aim to emphasize the significance of IDRs for the flexibility and function of bHLH–PAS proteins. Finally, we propose modern NMR methods for the structural characterization of the IDRs of bHLH–PAS proteins.
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Affiliation(s)
- Marta Kolonko
- Department of Biochemistry, Faculty of Chemistry, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland
| | - Beata Greb-Markiewicz
- Department of Biochemistry, Faculty of Chemistry, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland.
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10
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Xu QY, Du JL, Mu LL, Guo WC, Li GQ. Importance of Taiman in Larval-Pupal Transition in Leptinotarsa decemlineata. Front Physiol 2019; 10:724. [PMID: 31263425 PMCID: PMC6584964 DOI: 10.3389/fphys.2019.00724] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Accepted: 05/27/2019] [Indexed: 02/01/2023] Open
Abstract
Insect Taiman (Tai) binds to methoprene-tolerant to form a heterodimeric complex, mediating juvenile hormone (JH) signaling to regulate larval development and to prevent premature metamorphosis. Tai also acts as a steroid receptor coactivator of 20-hydroxyecdysone (20E) receptor heterodimer, ecdysone receptor (EcR) and Ultraspiracle (USP), to control the differentiation of early germline cells and the migration of specific follicle cells and border cells in ovaries in several insect species. In holometabolous insects, however, whether Tai functions as the coactivator of EcR/USP to transduce 20E message during larval-pupal transition is unknown. In the present paper, we found that the LdTai mRNA levels were positively correlated with circulating JH and 20E titers in Leptinotarsa decemlineata; and ingestion of either JH or 20E stimulated the transcription of LdTai. Moreover, RNA interference (RNAi)-aided knockdown of LdTai at the fourth (final) instar stage repressed both JH and 20E signals, inhibited larval growth and shortened larval developing period. The knockdown caused 100% larval lethality due to failure of larval-pupal ecdysis. Under the apolysed larval cuticle, the LdTai RNAi prepupae possessed pupal thorax. In contrast, the process of tracheal ecdysis was uncompleted. Neither JH nor 20E rescued the aforementioned defectives in LdTai RNAi larvae. It appears that Tai mediates both JH and 20E signaling. Our results uncover a link between JH and 20E pathways during metamorphosis in L. decemlineata.
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Affiliation(s)
- Qing-Yu Xu
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Jun-Li Du
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, College of Plant Protection, Nanjing Agricultural University, Nanjing, China.,College of Agriculture, Anhui Science and Technology University, Fengyang, China
| | - Li-Li Mu
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Wen-Chao Guo
- Institute of Plant Protection, Xinjiang Academy of Agricultural Sciences, Urumqi, China.,Key Laboratory of Intergraded Management of Harmful Crop Vermin of China North-Western Oasis, Ministry of Agriculture, Urumqi, China
| | - Guo-Qing Li
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
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11
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Garg N, Kumar P, Gadhave K, Giri R. The dark proteome of cancer: Intrinsic disorderedness and functionality of HIF-1α along with its interacting proteins. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2019; 166:371-403. [PMID: 31521236 DOI: 10.1016/bs.pmbts.2019.05.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The dark side of protein is the region (s) where molecular conformation is unknown. Intrinsically disordered proteins (IDPs) and intrinsically disordered protein regions (IDPRs) are the dark matter of biology due to inability to visualize them using standard structure elucidation technique such as X-ray crystallography due to lack in diffraction signal. IDPs are the functionally important class of proteins with entire protein or its parts lack ordered three-dimensional structure. Computational studies have predicted that nearly one-third of the human proteome is disordered, which gives the enormous flexibility and functional diversity to proteins. The conserved residues and elements in disordered proteins are critical for function and might be parts of peptide motifs or protein-protein interaction interfaces. For example, regions of proteins that are involved in disorder-based molecular recognition are known as molecular recognition features (MoRFs). Generally, MoRFs could undergo disorder to order transition or vice versa at interaction with specific partners. Hypoxia inducible factor 1α (HIF-1α) is a master transcriptional regulator involved in response to hypoxia, which is associated with many pathological conditions. Importantly, HIF-1α regulates various steps of cancer progression such as cell survival, tumor cell invasion, and metastasis. In this chapter, we have extensively analyzed the molecular recognition features and their relationship with disordered regions and associated structural islands of HIF-1α. We had also analyzed the disorderness and MoRFs of HIF-1α primary interaction partners that are enriched in IDPRs and MoRFs giving their role in protein-protein interaction and cancer regulation.
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Affiliation(s)
- Neha Garg
- School of Basic Sciences, Indian Institute of Technology Mandi, Mandi, Himachal Pradesh, India
| | - Prateek Kumar
- School of Basic Sciences, Indian Institute of Technology Mandi, Mandi, Himachal Pradesh, India
| | - Kundlik Gadhave
- School of Basic Sciences, Indian Institute of Technology Mandi, Mandi, Himachal Pradesh, India
| | - Rajanish Giri
- School of Basic Sciences, Indian Institute of Technology Mandi, Mandi, Himachal Pradesh, India.
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12
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Lin YS, Lu SY, Wu HP, Chang CF, Chiu YT, Yang HT, Chao PM. Is frying oil a dietary source of an endocrine disruptor? Anti-estrogenic effects of polar compounds from frying oil in rats. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 169:18-27. [PMID: 30412894 DOI: 10.1016/j.ecoenv.2018.10.111] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/16/2018] [Accepted: 10/30/2018] [Indexed: 06/08/2023]
Abstract
The objective was to investigate endocrine-disrupting effects of polar compounds from oxidized frying oil. Estrogenicity of polar compounds was tested with a rat uterotrophic bioassay. Dietary oxidized frying oil (containing 51% polar compounds) or polar compounds isolated from it were incorporated into feed (in lieu of fresh soybean oil) and fed to ovariectomized rats, with or without treatment with exogenous ethynyl estradiol. Exogenous estrogen restored uterine weight, and caused histological abnormalities (stratified epithelia and conglomerate glands) as well as proliferation of uterine epithelial cells. However, tamoxifen or polar compounds reduced these effects. Furthermore, tamoxifen or polar compounds down-regulated uterine mRNA expression of estrogen receptor (ER)-target genes, implicating reduced ER activity in this hypo-uterotrophic effect. Inhibition of ER signaling and mitosis by polar compounds were attributed to reduced MAPK and AKT activation, as well as a reduced ligand binding domain-transactivity of ERα/β. We concluded polar compounds from frying oil are potential endocrine-disrupting chemicals, with implications for food and environmental safety.
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Affiliation(s)
- Yu-Shun Lin
- Department of Nutrition, China Medical University, Taichung 404, Taiwan
| | - Shui-Yuan Lu
- Department of Applied Toxicology, Taiwan Agricultural Chemicals and Toxic Substances Research Institute, Taichung 413, Taiwan
| | - Hai-Ping Wu
- Department of Nutrition, China Medical University, Taichung 404, Taiwan
| | - Chi-Fen Chang
- Department of Anatomy, School of Medicine, China Medical University, Taichung 404, Taiwan
| | - Yung-Tsung Chiu
- Department of Medical Education and Research, Taichung Veterans General Hospital, Taichung 407, Taiwan
| | - Hui-Ting Yang
- Department of Nutrition, China Medical University, Taichung 404, Taiwan
| | - Pei-Min Chao
- Department of Nutrition, China Medical University, Taichung 404, Taiwan.
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Crosstalk between Notch, HIF-1α and GPER in Breast Cancer EMT. Int J Mol Sci 2018; 19:ijms19072011. [PMID: 29996493 PMCID: PMC6073901 DOI: 10.3390/ijms19072011] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 07/04/2018] [Accepted: 07/09/2018] [Indexed: 12/15/2022] Open
Abstract
The Notch signaling pathway acts in both physiological and pathological conditions, including embryonic development and tumorigenesis. In cancer progression, diverse mechanisms are involved in Notch-mediated biological responses, including angiogenesis and epithelial-mesenchymal-transition (EMT). During EMT, the activation of cellular programs facilitated by transcriptional repressors results in epithelial cells losing their differentiated features, like cell–cell adhesion and apical–basal polarity, whereas they gain motility. As it concerns cancer epithelial cells, EMT may be consequent to the evolution of genetic/epigenetic instability, or triggered by factors that can act within the tumor microenvironment. Following a description of the Notch signaling pathway and its major regulatory nodes, we focus on studies that have given insights into the functional interaction between Notch signaling and either hypoxia or estrogen in breast cancer cells, with a particular focus on EMT. Furthermore, we describe the role of hypoxia signaling in breast cancer cells and discuss recent evidence regarding a functional interaction between HIF-1α and GPER in both breast cancer cells and cancer-associated fibroblasts (CAFs). On the basis of these studies, we propose that a functional network between HIF-1α, GPER and Notch may integrate tumor microenvironmental cues to induce robust EMT in cancer cells. Further investigations are required in order to better understand how hypoxia and estrogen signaling may converge on Notch-mediated EMT within the context of the stroma and tumor cells interaction. However, the data discussed here may anticipate the potential benefits of further pharmacological strategies targeting breast cancer progression.
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14
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Yang J, Harris AL, Davidoff AM. Hypoxia and Hormone-Mediated Pathways Converge at the Histone Demethylase KDM4B in Cancer. Int J Mol Sci 2018; 19:E240. [PMID: 29342868 PMCID: PMC5796188 DOI: 10.3390/ijms19010240] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 01/08/2018] [Accepted: 01/09/2018] [Indexed: 02/07/2023] Open
Abstract
Hormones play an important role in pathophysiology. The hormone receptors, such as estrogen receptor alpha and androgen receptor in breast cancer and prostate cancer, are critical to cancer cell proliferation and tumor growth. In this review we focused on the cross-talk between hormone and hypoxia pathways, particularly in breast cancer. We delineated a novel signaling pathway from estrogen receptor to hypoxia-inducible factor 1, and discussed the role of this pathway in endocrine therapy resistance. Further, we discussed the estrogen and hypoxia pathways converging at histone demethylase KDM4B, an important epigenetic modifier in cancer.
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Affiliation(s)
- Jun Yang
- Department of Surgery, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA.
| | - Adrian L Harris
- Molecular Oncology Laboratories, Department of Oncology, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK.
| | - Andrew M Davidoff
- Department of Surgery, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA.
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15
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Chapman EC, O’Dell AR, Meligi NM, Parsons DR, Rotchell JM. Seasonal expression patterns of clock-associated genes in the blue mussel Mytilus edulis. Chronobiol Int 2017; 34:1300-1314. [DOI: 10.1080/07420528.2017.1363224] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Emma C. Chapman
- School of Environmental Sciences, University of Hull, Hull, UK
| | | | - Noha M. Meligi
- Zoology Department, Faculty of Science, Minia University, Minia, Egypt
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16
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Jackson E, Shoemaker R, Larian N, Cassis L. Adipose Tissue as a Site of Toxin Accumulation. Compr Physiol 2017; 7:1085-1135. [PMID: 28915320 DOI: 10.1002/cphy.c160038] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
We examine the role of adipose tissue, typically considered an energy storage site, as a potential site of toxicant accumulation. Although the production of most persistent organic pollutants (POPs) was banned years ago, these toxicants persist in the environment due to their resistance to biodegradation and widespread distribution in various environmental forms (e.g., vapor, sediment, and water). As a result, human exposure to these toxicants is inevitable. Largely due to their lipophilicity, POPs bioaccumulate in adipose tissue, resulting in greater body burdens of these environmental toxicants with obesity. POPs of major concern include polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and furans (PCDDs/PCDFs), and polybrominated biphenyls and diphenyl ethers (PBBs/PBDEs), among other organic compounds. In this review, we (i) highlight the physical characteristics of toxicants that enable them to partition into and remain stored in adipose tissue, (ii) discuss the specific mechanisms of action by which these toxicants act to influence adipocyte function, and (iii) review associations between POP exposures and the development of obesity and diabetes. An area of controversy relates to the relative potential beneficial versus hazardous health effects of toxicant sequestration in adipose tissue. © 2017 American Physiological Society. Compr Physiol 7:1085-1135, 2017.
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Affiliation(s)
- Erin Jackson
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Robin Shoemaker
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Nika Larian
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Lisa Cassis
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, Kentucky, USA
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17
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Hultman MT, Petersen K, Tollefsen KE. Characterizing combined effects of antiestrogenic chemicals on vitellogenin production in rainbow trout (Oncorhynchus mykiss) hepatocytes. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2017; 80:987-1001. [PMID: 28849994 DOI: 10.1080/15287394.2017.1354435] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Fish are exposed to a complex mixture of endocrine disrupting compounds (EDC), some of which display antiestrogenic activity leading to suppression of estrogen receptor (ER)- mediated reproductive processes. Although the main mode of action (MoA) of these antiestrogens is to directly interfere with natural ligand binding of the ER, several other MoA have been proposed. The aim of the present study was to characterize single and combined antiestrogenic effects of the aryl hydrocarbon receptor (AhR)-agonist β-naphthoflavone (BNF) and ER-antagonist 4-hydroxytamoxifen (OHT) on vitellogenin (Vtg) protein using primary rainbow trout (Oncorhynchus mykiss) hepatocytes. Supporting transcriptional analysis of ER-responsive genes (estrogen receptor-α (er-α), vitellogenin-1 (vtg-1), eggshell zona radiata protein (zrp)) and AhR-mediated genes (aryl hydrocarbon receptor-2β, cytochrome p450-1a (cyp1a)) was performed by qPCR to characterize the antiestrogenic influence on ER- and AhR-mediated responses. Data demonstrated that both BNF and OHT significantly reduced 17β-estradiol (E2)-induced Vtg protein expression in a concentration responsive manner, whereas exposure to a mixture of these produced an additive antiestrogenic effect. The results observed at the protein level were further supported by transcriptional analysis of ER-responsive genes (er-α, vtg-1, zrp), where only E2-induced vtg-1 gene expression was significantly decreased by OHT and the mixture of OHT and BNF. E2-induced er-α and zrp gene expression was not markedly altered. The significant reduction of E2-induced vtg-1 gene expression by OHT suggested that the antiestrogenic effect of this compound may be associated with ER signaling pathway. Specific genes involved in putative AhR-ER cross-talk were also investigated, however none were directly associated with the compound anti-estrogenic MoA. Although the MoA of the single compounds and mixture were not completely characterized, the present study enhanced our knowledge of the combined toxicity mediated by antiestrogens acting through different MoA.
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Affiliation(s)
- Maria T Hultman
- a Norwegian Institute for Water Research (NIVA) , Oslo , Norway
| | - Karina Petersen
- a Norwegian Institute for Water Research (NIVA) , Oslo , Norway
| | - Knut Erik Tollefsen
- a Norwegian Institute for Water Research (NIVA) , Oslo , Norway
- b Faculty of Environmental Science & Technology, Department for Environmental Sciences , Norwegian University of Life Sciences (NMBU) , Ås , Norway
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18
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A Molecular Mechanism To Switch the Aryl Hydrocarbon Receptor from a Transcription Factor to an E3 Ubiquitin Ligase. Mol Cell Biol 2017; 37:MCB.00630-16. [PMID: 28416634 DOI: 10.1128/mcb.00630-16] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 04/10/2017] [Indexed: 01/01/2023] Open
Abstract
The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that is known as a mediator of toxic responses. Recently, it was shown that the AhR has dual functions. Besides being a transcription factor, it also possesses an intrinsic E3 ubiquitin ligase function that targets, e.g., the steroid receptors for proteasomal degradation. The aim of this study was to identify the molecular switch that determines whether the AhR acts as a transcription factor or an E3 ubiquitin ligase. To do this, we used the breast cancer cell line MCF7, which expresses a functional estrogen receptor alpha (ERα) signaling pathway. Our data suggest that aryl hydrocarbon receptor nuclear translocator (ARNT) plays an important role in the modulation of the dual functions of the AhR. ARNT knockdown dramatically impaired the transcriptional activation properties of the ligand-activated AhR but did not affect its E3 ubiquitin ligase function. The availability of ARNT itself is modulated by another basic helix-loop-helix (bHLH)-Per-ARNT-SIM (PAS) protein, the repressor of AhR function (AhRR). MCF7 cells overexpressing the AhRR showed lower ERα protein levels, reduced responsiveness to estradiol, and reduced growth rates. Importantly, when these cells were used to produce estrogen-dependent xenograft tumors in SCID mice, we also observed lower ERα protein levels and a reduced tumor mass, implying a tumor-suppressive-like function of the AhR in MCF7 xenograft tumors.
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19
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Endocrine Disruption and In Vitro Ecotoxicology: Recent Advances and Approaches. IN VITRO ENVIRONMENTAL TOXICOLOGY - CONCEPTS, APPLICATION AND ASSESSMENT 2017; 157:1-58. [DOI: 10.1007/10_2016_2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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20
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Manente AG, Pinton G, Zonca S, Cilli M, Rinaldi M, Daga A, Nilsson S, Moro L. Intracellular lactate-mediated induction of estrogen receptor beta (ERβ) in biphasic malignant pleural mesothelioma cells. Oncotarget 2016. [PMID: 26208479 PMCID: PMC4694819 DOI: 10.18632/oncotarget.4486] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Biphasic malignant pleural mesothelioma (MPM) is the second most common histotype of MPM. It is histologically characterized by the concomitant presence of epithelioid and sarcomatoid features, the latter associated with worse prognosis. In this report we describe that silencing of AKT1 in spindle-shaped biphasic MPM cells promotes the shift toward an epithelioid phenotype. Furthermore, AKT1 silencing resulted in decreased expression of the lactate/H+ symporter MCT4 and its chaperone CD147/Basigin, and in the induction of estrogen receptor β (ERβ) expression. We provide evidence that ERβ expression is induced by increased intracellular lactate concentration. Spheroid culturing and tumor growth of ERβ negative biphasic MPM in nude mice resulted in the induction of ERβ expression and response to the selective agonist KB9520. In both models, the treatment with the ERβ agonist results in reduced cell proliferation, decreased expression of MCT4 and CD147/Basigin and increased acetylation and inactivation of AKT1. Collectively, in response to metabolic changes, ERβ expression is induced and exerts an anti-tumor effect through selective agonist activation. The possibility to reverse the more aggressive biphasic mesothelioma histotype by targeting ERβ with a selective agonist could represent a new effective treatment strategy.
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Affiliation(s)
- Arcangela G Manente
- Department of Pharmaceutical Sciences, University of Piemonte Orientale "A. Avogadro", 28100, Novara, Italy
| | - Giulia Pinton
- Department of Pharmaceutical Sciences, University of Piemonte Orientale "A. Avogadro", 28100, Novara, Italy
| | - Sara Zonca
- Department of Pharmaceutical Sciences, University of Piemonte Orientale "A. Avogadro", 28100, Novara, Italy
| | | | - Maurizio Rinaldi
- Department of Pharmaceutical Sciences, University of Piemonte Orientale "A. Avogadro", 28100, Novara, Italy
| | | | - Stefan Nilsson
- Karo Bio AB, Novum, S-141 57, Huddinge, Sweden.,Department of Biosciences and Nutrition, Karolinska Institutet, Novum, S-141 57, Huddinge, Sweden
| | - Laura Moro
- Department of Pharmaceutical Sciences, University of Piemonte Orientale "A. Avogadro", 28100, Novara, Italy
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21
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Yang J, AlTahan A, Jones DT, Buffa FM, Bridges E, Interiano RB, Qu C, Vogt N, Li JL, Baban D, Ragoussis J, Nicholson R, Davidoff AM, Harris AL. Estrogen receptor-α directly regulates the hypoxia-inducible factor 1 pathway associated with antiestrogen response in breast cancer. Proc Natl Acad Sci U S A 2015; 112:15172-7. [PMID: 26598706 PMCID: PMC4679044 DOI: 10.1073/pnas.1422015112] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A majority of breast cancers are driven by estrogen via estrogen receptor-α (ERα). Our previous studies indicate that hypoxia-inducible factor 1α (HIF-1α) cooperates with ERα in breast cancer cells. However, whether ERα is implicated in the direct regulation of HIF-1α and the role of HIF-1α in endocrine therapy response are unknown. In this study we found that a subpopulation of HIF-1α targets, many of them bearing both hypoxia response elements and estrogen response elements, are regulated by ERα in normoxia and hypoxia. Interestingly, the HIF-1α gene itself also bears an estrogen response element, and its expression is directly regulated by ERα. Clinical data revealed that expression of the HIF-1α gene or a hypoxia metagene signature is associated with a poor outcome to endocrine treatment in ERα(+) breast cancer. HIF-1α was able to confer endocrine therapy resistance to ERα(+) breast cancer cells. Our findings define, for the first time to our knowledge, a direct regulatory pathway between ERα and HIF-1α, which might modulate hormone response in treatment.
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Affiliation(s)
- Jun Yang
- Growth Factor Group, Cancer Research UK, Molecular Oncology Laboratories, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DS, United Kingdom; Department of Surgery, St. Jude Children's Research Hospital, Memphis, TN 38105;
| | - Alaa AlTahan
- Department of Surgery, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Dylan T Jones
- Growth Factor Group, Cancer Research UK, Molecular Oncology Laboratories, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DS, United Kingdom
| | - Francesca M Buffa
- Growth Factor Group, Cancer Research UK, Molecular Oncology Laboratories, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DS, United Kingdom
| | - Esther Bridges
- Growth Factor Group, Cancer Research UK, Molecular Oncology Laboratories, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DS, United Kingdom
| | - Rodrigo B Interiano
- Department of Surgery, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Chunxu Qu
- Department of Bioinformatics, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Nathan Vogt
- Department of Surgery, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Ji-Liang Li
- Growth Factor Group, Cancer Research UK, Molecular Oncology Laboratories, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DS, United Kingdom
| | - Dilair Baban
- Genomics Group, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - Jiannis Ragoussis
- Genomics Group, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - Robert Nicholson
- Tenovus Centre for Cancer Research, Welsh School of Pharmacy, Cardiff University, Cardiff CF10 3NB, United Kingdom
| | - Andrew M Davidoff
- Department of Surgery, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Adrian L Harris
- Growth Factor Group, Cancer Research UK, Molecular Oncology Laboratories, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DS, United Kingdom
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22
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Simon TW, Budinsky RA, Rowlands JC. A model for aryl hydrocarbon receptor-activated gene expression shows potency and efficacy changes and predicts squelching due to competition for transcription co-activators. PLoS One 2015; 10:e0127952. [PMID: 26039703 PMCID: PMC4454675 DOI: 10.1371/journal.pone.0127952] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 04/22/2015] [Indexed: 12/17/2022] Open
Abstract
A stochastic model of nuclear receptor-mediated transcription was developed based on activation of the aryl hydrocarbon receptor (AHR) by 2,3,7,8-tetrachlorodibenzodioxin (TCDD) and subsequent binding the activated AHR to xenobiotic response elements (XREs) on DNA. The model was based on effects observed in cells lines commonly used as in vitro experimental systems. Following ligand binding, the AHR moves into the cell nucleus and forms a heterodimer with the aryl hydrocarbon nuclear translocator (ARNT). In the model, a requirement for binding to DNA is that a generic coregulatory protein is subsequently bound to the AHR-ARNT dimer. Varying the amount of coregulator available within the nucleus altered both the potency and efficacy of TCDD for inducing for transcription of CYP1A1 mRNA, a commonly used marker for activation of the AHR. Lowering the amount of available cofactor slightly increased the EC50 for the transcriptional response without changing the efficacy or maximal response. Further reduction in the amount of cofactor reduced the efficacy and produced non-monotonic dose-response curves (NMDRCs) at higher ligand concentrations. The shapes of these NMDRCs were reminiscent of the phenomenon of squelching. Resource limitations for transcriptional machinery are becoming apparent in eukaryotic cells. Within single cells, nuclear receptor-mediated gene expression appears to be a stochastic process; however, intercellular communication and other aspects of tissue coordination may represent a compensatory process to maintain an organism’s ability to respond on a phenotypic level to various stimuli within an inconstant environment.
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Affiliation(s)
- Ted W. Simon
- Ted Simon LLC, Winston, GA, United States of America
- * E-mail:
| | - Robert A. Budinsky
- The Dow Chemical Company, Toxicology and Environmental Research & Consulting. Midland, MI, United States of America
| | - J. Craig Rowlands
- The Dow Chemical Company, Toxicology and Environmental Research & Consulting. Midland, MI, United States of America
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23
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Brokken LJS, Giwercman YL. Gene-environment interactions in male reproductive health: special reference to the aryl hydrocarbon receptor signaling pathway. Asian J Androl 2014; 16:89-96. [PMID: 24369137 PMCID: PMC3901886 DOI: 10.4103/1008-682x.122193] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Over the last few decades, there have been numerous reports of adverse effects on the reproductive health of wildlife and laboratory animals caused by exposure to endocrine disrupting chemicals (EDCs). The increasing trends in human male reproductive disorders and the mounting evidence for causative environmental factors have therefore sparked growing interest in the health threat posed to humans by EDCs, which are substances in our food, environment and consumer items that interfere with hormone action, biosynthesis or metabolism, resulting in disrupted tissue homeostasis or reproductive function. The mechanisms of EDCs involve a wide array of actions and pathways. Examples include the estrogenic, androgenic, thyroid and retinoid pathways, in which the EDCs may act directly as agonists or antagonists, or indirectly via other nuclear receptors. Dioxins and dioxin-like EDCs exert their biological and toxicological actions through activation of the aryl hydrocarbon-receptor, which besides inducing transcription of detoxifying enzymes also regulates transcriptional activity of other nuclear receptors. There is increasing evidence that genetic predispositions may modify the susceptibility to adverse effects of toxic chemicals. In this review, potential consequences of hereditary predisposition and EDCs are discussed, with a special focus on the currently available publications on interactions between dioxin and androgen signaling.
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Affiliation(s)
- Leon J S Brokken
- Department of Clinical Sciences, Molecular Genetic Reproductive Medicine, Lund University, Malmö, Sweden
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24
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Li M, Liu P, Wiley JD, Ojani R, Bevan DR, Li J, Zhu J. A steroid receptor coactivator acts as the DNA-binding partner of the methoprene-tolerant protein in regulating juvenile hormone response genes. Mol Cell Endocrinol 2014; 394:47-58. [PMID: 25004255 PMCID: PMC4163509 DOI: 10.1016/j.mce.2014.06.021] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 06/20/2014] [Accepted: 06/30/2014] [Indexed: 10/25/2022]
Abstract
Methoprene-tolerant (Met) protein is a juvenile hormone (JH) receptor in insects. JH-bound Met forms a complex with the βFtz-F1-interacting steroid receptor coactivator (FISC) and together they regulate JH response genes in mosquitoes. Both proteins contain basic helix-loop-helix (bHLH) and PAS motifs. Here we demonstrated that FISC is the obligatory partner of Met for binding to JH-response elements (JHREs). Met or FISC alone could not bind a previously characterized JHRE, while formation of the Met-FISC complex was necessary and sufficient to bind to the JHRE. This binding required participation of the DNA-binding domains of both Met and FISC. The optimal DNA sequence recognized by Met and FISC contained a core consensus sequence GCACGTG. While formation of the Met-FISC complex in mosquito cells was induced by JH, heterodimerization and DNA binding of bacterially expressed Met and FISC were JH-independent, implying that additional mosquito proteins were required to modulate formation of the receptor complex.
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Affiliation(s)
- Meng Li
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | - Pengcheng Liu
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | - Jessica D Wiley
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | - Reyhaneh Ojani
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | - David R Bevan
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | - Jianyong Li
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | - Jinsong Zhu
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA.
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25
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Jung JW, Shim SY, Lee DK, Kwiatkowski W, Choe S. An Activin A/BMP2 chimera, AB215, blocks estrogen signaling via induction of ID proteins in breast cancer cells. BMC Cancer 2014; 14:549. [PMID: 25070479 PMCID: PMC4122783 DOI: 10.1186/1471-2407-14-549] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 07/21/2014] [Indexed: 11/18/2022] Open
Abstract
Background One in eight women will be affected by breast cancer in her lifetime. Approximately 75% of breast cancers express estrogen receptor alpha (ERα) and/or progesterone receptor and these receptors are markers for tumor dependence on estrogen. Anti-estrogenic drugs such as tamoxifen are commonly used to block estrogen-mediated signaling in breast cancer. However, many patients either do not respond to these therapies (de novo resistance) or develop resistance to them following prolonged treatment (acquired resistance). Therefore, it is imperative to continue efforts aimed at developing new efficient and safe methods of targeting ER activity in breast cancer. Methods AB215 is a chimeric ligand assembled from sections of Activin A and BMP2. BMP2’s and AB215’s inhibition of breast cancer cells growth was investigated. In vitro luciferase and MTT proliferation assays together with western blot, RT_PCR, and mRNA knockdown methods were used to determine the mechanism of inhibition of estrogen positive breast cancer cells growth by BMP2 and AB215. Additionally in vivo xenograft tumor model was used to investigate anticancer properties of AB215. Results Here we report that AB215, a chimeric ligand assembled from sections of Activin A and BMP2 with BMP2-like signaling, possesses stronger anti-proliferative effects on ERα positive breast cancer cells than BMP2. We further show that AB215 inhibits estrogen signaling by inducing expression of inhibitor of DNA binding proteins (IDs). Specifically, we demonstrate that knockdown of ID proteins attenuates the anti-estrogen effects of AB215. Remarkably, we find that AB215 is more effective than tamoxifen in suppressing tumor growth in a xenograft model. Conclusion This study shows that IDs have profound role to inhibit estrogen signaling in ERα positive breast cancer cells, and that engineered TGF-beta ligands may have high therapeutic value. Electronic supplementary material The online version of this article (doi:10.1186/1471-2407-14-549) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | - Senyon Choe
- Joint Center for Biosciences, Songdo Global University Campus, 187 Songdo-dong, Incheon 406-840, Yeonsu-gu, Korea.
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26
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Endler A, Chen L, Shibasaki F. Coactivator recruitment of AhR/ARNT1. Int J Mol Sci 2014; 15:11100-10. [PMID: 24950180 PMCID: PMC4100201 DOI: 10.3390/ijms150611100] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 05/27/2014] [Accepted: 06/07/2014] [Indexed: 01/03/2023] Open
Abstract
A common feature of nuclear receptors (NRs) is the transformation of external cell signals into specific transcriptions of the signal molecule. Signal molecules function as ligands for NRs and, after their uptake, activated NRs form homo- or heterodimers at promoter recognition sequences of the specific genes in the nucleus. Another common feature of NRs is their dependence on coactivators, which bridge the basic transcriptional machinery and other cofactors to the target genes, in order to initiate transcription and to unwind histone-bound DNA for exposing additional promoter recognition sites via their histone acetyltransferase (HAT) function. In this review, we focus on our recent findings related to the recruitment of steroid receptor coactivator 1 (SRC1/NCoA1) by the estrogen receptor-α (ERα) and by the arylhydrocarbon receptor/arylhydrocarbon receptor nuclear translocator 1 (AhR/ARNT1) complex. We also describe the extension of our previously published findings regarding the binding between ARNT1.1 exon16 and SRC1e exon 21, via in silico analyses of androgen receptor (AR) NH2-carboxyl-terminal interactions, the results of which were verified by in vitro experiments. Based on these data, we suggest a newly derived tentative binding site of nuclear coactivator 2/glucocorticoid receptor interacting protein-1/transcriptional intermediary factor 2 (NCOA-2/ GRIP-1/TIF-2) for ARNT1.1 exon 16. Furthermore, results obtained by immunoprecipitation have revealed a second leucine-rich binding site for hARNT1.1 exon 16 in SRC1e exon 21 (LSSTDLL). Finally, we discuss the role of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as an endocrine disruptor for estrogen related transcription.
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Affiliation(s)
- Alexander Endler
- Department of Molecular Medical Research, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
| | - Li Chen
- Department of Molecular Medical Research, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
| | - Futoshi Shibasaki
- Department of Molecular Medical Research, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
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Park C, Lee Y. Overexpression of ERβ is sufficient to inhibit hypoxia-inducible factor-1 transactivation. Biochem Biophys Res Commun 2014; 450:261-6. [PMID: 24938129 DOI: 10.1016/j.bbrc.2014.05.107] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 05/23/2014] [Indexed: 10/25/2022]
Abstract
Estrogen receptor (ER) β is predicted to play an important role in the prevention of breast cancer development and progression. We have previously shown that ERβ suppresses hypoxia inducible factor (HIF)-1-mediated transcription through aryl hydrocarbon receptor nuclear translocator (ARNT) degradation via ubiquitination processes. In this study, we attempted to examine the effect of ERβ specific ligand on HIF-1 inhibition in ERβ positive PC3 cells and ERβ transfected MCF-7 cells. ERβ specific agonist diarylpropionitrile (DPN) stimulated estrogen response element (ERE)-luciferase activity in a similar fashion to estradiol in PC3 cells. We observed that DPN down-regulates the ARNT protein levels leading to an attenuation of hypoxia-induced hypoxia response element (HRE)-driven luciferase reporter gene activation in PC3 cells. Treatment of DPN reduced vascular endothelial growth factor (VEGF) expression and co-treatment with ERβ specific antagonist PHTPP abrogated the effect in PC3 cells. We then examined the effect of DPN in ERβ transfected MCF-7 cells. HIF-1 transcriptional activity repression by ERβ was not further reduced by DPN, as examined by HRE-driven luciferase assays. Expression of ERβ significantly decreased VEGF secretion and ARNT expression under hypoxic conditions. However, DPN did not additionally affect this suppression in MCF-7 cells transfected with ERβ. This result shows that unliganded ERβ is sufficient to inhibit HIF-1 in systems of overexpression.
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Affiliation(s)
- Choa Park
- Department of Bioscience and Biotechnology, College of Life Science, Institute of Biotechnology, Sejong University, Kwangjingu, Kunjadong, Seoul 143-747, Republic of Korea
| | - YoungJoo Lee
- Department of Bioscience and Biotechnology, College of Life Science, Institute of Biotechnology, Sejong University, Kwangjingu, Kunjadong, Seoul 143-747, Republic of Korea.
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Lalwani A, Stokes RA, Lau SM, Gunton JE. Deletion of ARNT (Aryl hydrocarbon receptor nuclear translocator) in β-cells causes islet transplant failure with impaired β-cell function. PLoS One 2014; 9:e98435. [PMID: 24878748 PMCID: PMC4039512 DOI: 10.1371/journal.pone.0098435] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 05/03/2014] [Indexed: 01/13/2023] Open
Abstract
Background Replacing β-cells by islet-transplantation can cure type 1 diabetes, but up to 70% of β-cells die within 10 days of transplantation. ARNT (Aryl hydrocarbon Receptor Nuclear Translocator) regulates β-cell function, and potentially survival. Lack of ARNT impairs the ability of β-cells to respond to physiological stress and potentiates the onset of diabetes, but the exact role of ARNT in graft outcome is unknown. Aim To investigate the effect of β-cell deletion of ARNT on graft outcomes. Methods Islets were isolated from donor mice which had β-cell specific ARNT-deletion (β-ARNT) or littermate floxed controls. The islets were transplanted into diabetic SCID recipients in ratios of (a) 3 donors: 1 recipient, (b) 1 donor: 1 recipient or (c) ½ of the islets from 1 donor: 1 recipient. After 28 days, the kidney containing the graft was removed (nephrectomy) to exclude regeneration of the endogenous pancreas. Results In the supra-physiological-mass model (3∶1), both groups achieved reasonable glycaemia, with slightly higher levels in β-ARNT-recipients. In adequate-mass model (1∶1), β-ARNT recipients had poor glucose control versus floxed-control recipients and versus the β-ARNT donors. In the low-β-cell-mass model (½:1) β-ARNT transplants completely failed, whereas controls had good outcomes. Unexpectedly, there was no difference in the graft insulin content or β-cell mass between groups indicating that the defect was not due to early altered β-cell survival. Conclusion Outcomes for islet transplants lacking β-cell ARNT were poor, unless markedly supra-physiological masses of islets were transplanted. In the 1∶1 transplant model, there was no difference in β-cell volume. This is surprising because transplants of islets lacking one of the ARNT-partners HIF-1α have increased apoptosis and decreased islet volume. ARNT also partners HIF-2α and AhR (aryl hydrocarbon receptor) to form active transcriptional complexes, and further work to understand the roles of HIF-2α and AhR in transplant outcomes is needed.
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Affiliation(s)
- Amit Lalwani
- Diabetes and Transcription Factors Group, Garvan Institute of Medical Research (GIMR), Sydney, Australia
- Faculty of Medicine, Westmead Hospital, University of Sydney, Sydney, Australia
| | - Rebecca A. Stokes
- Diabetes and Transcription Factors Group, Garvan Institute of Medical Research (GIMR), Sydney, Australia
| | - Sue Mei Lau
- Diabetes and Transcription Factors Group, Garvan Institute of Medical Research (GIMR), Sydney, Australia
- St Vincent’s Clinical School, University of New South Wales, Sydney, Australia
| | - Jenny E. Gunton
- Diabetes and Transcription Factors Group, Garvan Institute of Medical Research (GIMR), Sydney, Australia
- Faculty of Medicine, Westmead Hospital, University of Sydney, Sydney, Australia
- St Vincent’s Clinical School, University of New South Wales, Sydney, Australia
- Department of Diabetes and Endocrinology, Westmead Hospital, Sydney, Australia
- * E-mail:
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Kuo LC, Cheng LC, Lin CJ, Li LA. Dioxin and estrogen signaling in lung adenocarcinoma cells with different aryl hydrocarbon receptor/estrogen receptor α phenotypes. Am J Respir Cell Mol Biol 2014; 49:1064-73. [PMID: 23855798 DOI: 10.1165/rcmb.2012-0497oc] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Evidence suggests that estrogen affects the pulmonary response to carcinogenic pollutants, such as dioxins. In this study, we examined dioxin and estrogen signaling cross-talk in lung adenocarcinoma cell lines that were engineered to exhibit different aryl hydrocarbon receptor (AhR)/estrogen receptor (ER) α phenotypes. Data showed that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) weakly antagonized estrogen-activated ERα activity in cells expressing abundant ERα, but little AhR. Increase of AhR expression or presence of a dioxin-responsive element in proximity silenced the antiestrogenic effect of TCDD. AhR was bound to dioxin-responsive element and transcriptionally active in both TCDD-untreated and -treated lung adenocarcinoma cells. 17β-estradiol (E2) reduced basal and TCDD-induced AhR activity only in ERα-positive cells. AhR and ERα exhibited a protein-protein interaction in the presence of E2. Cotreatment with TCDD moderated this protein interaction. Colocalization of ERα and AhR at the estrogen-responsive site under E2 and TCDD/E2 treatments implied that E2 ∣ ERα might hijack AhR away from the dioxin-responsive site. Increasing the relative expression of AhR to ERα counteracted inhibition of AhR activity by E2 ∣ ERα. When AhR and ERα were both highly expressed, TCDD and E2 up-regulated expression of dual-responsive genes cytochrome P450 (CYP) 1A1 and CYP1B1 in a cumulative manner, increasing the danger of metabolic activation of carcinogens. Whereas TCDD ∣ AhR and E2 ∣ ERα appeared to regulate CYP1B1 separately through their binding sites, E2 ∣ ERα increased the TCDD responsiveness and mRNA expression of CYP1A1 in a noncanonical way. In conclusion, AhR/ERα expression pattern, estrogen level, and promoter context determine the genomic action of dioxin in lung adenocarcinoma cells.
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Affiliation(s)
- Lun-Cheng Kuo
- 1 Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Zhunan, Miaoli, Taiwan, Republic of China
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Ahmed S, Wang A, Celius T, Matthews J. Zinc finger nuclease-mediated knockout of AHR or ARNT in human breast cancer cells abolishes basal and ligand-dependent regulation of CYP1B1 and differentially affects estrogen receptor α transactivation. Toxicol Sci 2013; 138:89-103. [PMID: 24299737 DOI: 10.1093/toxsci/kft274] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
In this study, we used zinc finger nuclease-mediated knockout of the aryl hydrocarbon receptor (AHR) or AHR nuclear translocator (ARNT) in MCF7 and AHR knockout in MDA-MB-231 human breast cancer cells to investigate cross talk among AHR, ARNT, and estrogen receptor α (ERα). Knockout of AHR or ARNT prevented the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-dependent induction of all AHR target genes examined. Knockout of AHR or ARNT also significantly reduced basal cytochrome P4501B1 (CYP1B1) expression levels, which were restored with overexpression of either protein but not with a DNA binding-deficient AHR mutant. Basal and TCDD-, 17β-estradiol (E2)-, or TCDD + E2-dependent recruitment of AHR, ARNT, ERα, NCoA3, and RNA polymerase II to CYP1B1 as well as CYP1B1 mRNA levels were abolished in MCF7-AHR((ko)) and MDA-MB-231 AHR(ko) cells. However, reduced but significant E2-dependent recruitment of ERα, NCoA3, and RNA polymerase II to CYP1B1 and weak increases in CYP1B1 mRNA levels were observed in MCF7 ARNT((ko)) cells. Interestingly, E2-dependent increases in trefoil factor 1, but not growth regulation by estrogen in breast cancer 1 (GREB1) mRNA levels, were dependent on ARNT expression. Moreover, the TCDD-dependent increases in the proteolytic degradation of ERα were prevented by the loss of AHR or ARNT. Our data show that AHR and ARNT play critical roles in the basal, TCDD, and E2-induced regulation of CYP1B1 but also reveal distinct roles for both proteins in ERα transactivation.
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Affiliation(s)
- Shaimaa Ahmed
- Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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Reactivation of estrogen receptor α by vorinostat sensitizes mesenchymal-like triple-negative breast cancer to aminoflavone, a ligand of the aryl hydrocarbon receptor. PLoS One 2013; 8:e74525. [PMID: 24058584 PMCID: PMC3772827 DOI: 10.1371/journal.pone.0074525] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Accepted: 08/05/2013] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVE Aminoflavone (AF) acts as a ligand of the aryl hydrocarbon receptor (AhR). Expression of estrogen receptor α (ERα) and AhR-mediated transcriptional induction of CYP1A1 can sensitize breast cancer cells to AF. The objective of this study was to investigate the combined antitumor effect of AF and the histone deacetylase inhibitor vorinostat for treating mesenchymal-like triple-negative breast cancer (TNBC) as well as the underlying mechanisms of such treatment. METHODS In vitro antiproliferative activity of AFP464 (AF prodrug) in breast cancer cell lines was evaluated by MTS assay. In vitro, the combined effect of AFP464 and vorinostat on cell proliferation was assessed by the Chou-Talalay method. In vivo, antitumor activity of AFP464, given alone and in combination with vorinostat, was studied using TNBC xenograft models. Knockdown of ERα was performed using specific, small-interfering RNA. Western blot, quantitative RT-PCR, immunofluorescence, and immunohistochemical staining were performed to study the mechanisms underlying the combined antitumor effect. RESULTS Luminal and basal A subtype breast cancer cell lines were sensitive to AFP464, whereas basal B subtype or mesenchymal-like TNBC cells were resistant. Vorinostat sensitized mesenchymal-like TNBC MDA-MB-231 and Hs578T cells to AFP464. It also potentiated the antitumor activity of AFP464 in a xenograft model using MDA-MB-231 cells. In vitro and in vivo mechanistic studies suggested that vorinostat reactivated ERα expression and restored AhR-mediated transcriptional induction of CYP1A1. CONCLUSION The response of breast cancer cells to AF or AFP464 was associated with their gene expression profile. Vorinostat sensitized mesenchymal-like TNBC to AF, at least in part, by reactivating ERα expression and restoring the responsiveness of AhR to AF.
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Beckers A, Aaltonen LA, Daly AF, Karhu A. Familial isolated pituitary adenomas (FIPA) and the pituitary adenoma predisposition due to mutations in the aryl hydrocarbon receptor interacting protein (AIP) gene. Endocr Rev 2013; 34:239-77. [PMID: 23371967 PMCID: PMC3610678 DOI: 10.1210/er.2012-1013] [Citation(s) in RCA: 206] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Pituitary adenomas are one of the most frequent intracranial tumors and occur with a prevalence of approximately 1:1000 in the developed world. Pituitary adenomas have a serious disease burden, and their management involves neurosurgery, biological therapies, and radiotherapy. Early diagnosis of pituitary tumors while they are smaller may help increase cure rates. Few genetic predictors of pituitary adenoma development exist. Recent years have seen two separate, complimentary advances in inherited pituitary tumor research. The clinical condition of familial isolated pituitary adenomas (FIPA) has been described, which encompasses the familial occurrence of isolated pituitary adenomas outside of the setting of syndromic conditions like multiple endocrine neoplasia type 1 and Carney complex. FIPA families comprise approximately 2% of pituitary adenomas and represent a clinical entity with homogeneous or heterogeneous pituitary adenoma types occurring within the same kindred. The aryl hydrocarbon receptor interacting protein (AIP) gene has been identified as causing a pituitary adenoma predisposition of variable penetrance that accounts for 20% of FIPA families. Germline AIP mutations have been shown to associate with the occurrence of large pituitary adenomas that occur at a young age, predominantly in children/adolescents and young adults. AIP mutations are usually associated with somatotropinomas, but prolactinomas, nonfunctioning pituitary adenomas, Cushing disease, and other infrequent clinical adenoma types can also occur. Gigantism is a particular feature of AIP mutations and occurs in more than one third of affected somatotropinoma patients. Study of pituitary adenoma patients with AIP mutations has demonstrated that these cases raise clinical challenges to successful treatment. Extensive research on the biology of AIP and new advances in mouse Aip knockout models demonstrate multiple pathways by which AIP may contribute to tumorigenesis. This review assesses the current clinical and therapeutic characteristics of more than 200 FIPA families and addresses research findings among AIP mutation-bearing patients in different populations with pituitary adenomas.
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Affiliation(s)
- Albert Beckers
- Department of Endocrinology, Centre Hospitalier Universitaire de Liège, University of Liège, Domaine Universitaire du Sart-Tilman, 4000 Liège, Belgium.
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Shao R, Hu J, Feng Y, Billig H. Aberrant alteration of vascular endothelial growth factor-family signaling in human tubal ectopic pregnancy: what is known and unknown? INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2013; 6:810-815. [PMID: 23573332 PMCID: PMC3606875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 02/25/2013] [Indexed: 06/02/2023]
Abstract
More than 98% of ectopic pregnancies occur in the Fallopian tube. Because many facets of tubal ectopic pregnancy remain unclear, prediction, prevention and treatment of tubal ectopic pregnancy are still a major clinical challenge. Compelling evidence suggests that angiogenic growth factors are involved in normal and abnormal implantation. While acknowledging the importance of an intrauterine pregnancy requires the development of a local blood supply and angiogenesis, we hypothesize that the hypoxic- and estrogen-dependent regulation of vascular endothelial growth factor/placental growth factor expression, secretion, and signaling pathways that are possibly involved in the pathophysiology of tubal ectopic pregnancy. Our hypothesis may also lead to a new therapeutic strategy for women with tubal ectopic pregnancy.
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Affiliation(s)
- Ruijin Shao
- Department of Physiology/Endocrinology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg 40530, Sweden.
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Lyberopoulou A, Mylonis I, Papachristos G, Sagris D, Kalousi A, Befani C, Liakos P, Simos G, Georgatsou E. MgcRacGAP, a cytoskeleton regulator, inhibits HIF-1 transcriptional activity by blocking its dimerization. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:1378-87. [PMID: 23458834 DOI: 10.1016/j.bbamcr.2013.02.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 02/19/2013] [Accepted: 02/21/2013] [Indexed: 01/22/2023]
Abstract
Hypoxia inducible factor-1 (HIF-1), a dimeric transcription factor of the bHLH-PAS family, is comprised of HIF-1α, which is inducible by hypoxia and ARNT or HIF-1β, which is constitutively expressed. HIF-1 is involved in cellular homeostasis under hypoxia, in development and in several diseases affected by oxygen availability, particularly cancer. Since its expression is positively correlated with poor outcome prognosis for cancer patients, HIF-1 is a target for pharmaceutical therapy. We have previously shown that male germ cell Rac GTPase activating protein (MgcRacGAP), a regulator of Rho proteins which are principally involved in cytoskeletal organization, binds to HIF-1α and inhibits its transcriptional activity. In this work, we have explored the mechanism of the MgcRacGAP-mediated HIF-1 inactivation. We show that the Myo domain of MgcRacGAP, which is both necessary and sufficient for HIF-1 repression, binds to the PAS-B domain of HIF-1α. Furthermore MgcRacGAP competes with ARNT for binding to the HIF-1α PAS-B domain, as shown by in vitro binding pull down assays. In mammalian cells, ARNT overexpression can overcome the MgcRacGAP-mediated inhibition and MgcRacGAP binding to HIF-1α in vivo inhibits its dimerization with ARNT. We additionally present results indicating that MgcRacGAP binding to HIF-1α is specific, since it does not affect the transcriptional activity of HIF-2, a close evolutionary relative of HIF-1 also involved in hypoxia regulation and cancer. Our results reveal a new mechanism for HIF-1 transcriptional activity regulation, suggest a novel hypoxia-cytoskeleton link and provide new tools for selective HIF-1 inhibition.
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Zou S, Li X, Feng Y, Sun S, Li J, Egecioglu E, Billig H, Shao R. Comparison of the diagnostic values of circulating steroid hormones, VEGF-A, PIGF, and ADAM12 in women with ectopic pregnancy. J Transl Med 2013; 11:44. [PMID: 23421942 PMCID: PMC3585714 DOI: 10.1186/1479-5876-11-44] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 02/07/2013] [Indexed: 11/17/2022] Open
Abstract
Background Several peripheral proteins that might be useful for detecting the presence of ectopic pregnancy (EP) have been evaluated, but none have been proven entirely useful in the clinic. We investigated the presence and the possible changes in circulating molecules that distinguish between normal intrauterine pregnancy (IUP) and tubal ectopic pregnancy. Methods Non-pregnant women during the menstrual cycle, women with IUP, and women with tubal EP after informed consent. Serum levels of 17β-estradiol (E2), progesterone (P4), testosterone (T), beta-human chorionic gonadotropin (β-hCG), vascular endothelial growth factor-A (VEGF-A), placental growth factor (PIGF), and a distintegrin and metalloprotease protein 12 (ADAM12) were analyzed. Receiver operating characteristic analysis was used to assess the diagnostic discrimination of EP and gestational age-matched IUP. Results E2, P4, PIGF, and ADAM12 levels increased and β-hCG decreased throughout IUP. E2 and VEGF-A levels were significantly different between women with tubal EP and IUP. However, using a serum β-hCG cut-off of less than 1000 mIU/mL, P4 was significantly lower in women with tubal EP compared to IUP. Although E2 was inversely correlated with VEGF-A in women in the early stages of IUP, E2 was not correlated with VEGF-A in women with EP prior to tubal surgery. There were no significant differences in either PIGF or ADAM12 alone between women with tubal EP or IUP. Although no significant correlations were seen between E2 and PIGF or P4 and ADAM12 in women in the early stages of IUP, E2 was positively correlated with PIGF and P4 was positively correlated with ADAM12 in women with EP prior to tubal surgery. Our studies defined associations but not causality. Conclusions Individual measurements of serum E2 or VEGF-A levels are strongly related to early pregnancy outcomes for women with IUP and EP, and pregnancy-associated E2 and VEGF-A levels provide diagnostic accuracy for the presence of tubal EP. This study demonstrates that correlation analysis of E2/VEGF-A and E2/PIGF serum levels may be able to distinguish a tubal EP from a normal IUP.
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Affiliation(s)
- Shien Zou
- Department of Gynecology, Obstetrics and Gynecology Hospital of Fudan University, Shanghai 200011, China
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Gjernes MH, Schlenk D, Arukwe A. Estrogen receptor-hijacking by dioxin-like 3,3'4,4',5-pentachlorobiphenyl (PCB126) in salmon hepatocytes involves both receptor activation and receptor protein stability. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2012; 124-125:197-208. [PMID: 22982498 DOI: 10.1016/j.aquatox.2012.08.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 08/14/2012] [Accepted: 08/17/2012] [Indexed: 05/20/2023]
Abstract
Several hypotheses have been proposed explaining the interactions between estrogen receptor (ER) and aryl hydrocarbon receptor (AhR) signaling pathways in both fish and mammalian systems. In both piscine and mammalian systems, ligand-activated AhR may recruit basal ER (i.e. hijack) in the absence of ER ligand and bind to the estrogen responsive elements (ERE) to activate ER-responsive genes. We have evaluated, the roles of receptor activation and receptor-protein stability on dioxin-like [3,3'4,4',5-pentachlorobiphenyl: PCB 126] mediated ER-hijacking in a salmon in vitro system. Primary salmon hepatocytes were exposed to PCB126 (1, 10 and 50 nM) with or without an ER-antagonist (ICI), putative AhR inhibitor (3',4'-dimethoxyflavone; DMF) or protein synthesis inhibitor (cycloheximide; CHX). Hepatocytes were exposed for 6, 12 and 24h. The expression of genes and proteins involved in ER (ERα, ERβ and vitellogenin) and AhR (CYP1A1, AhR-repressor, AhR2-isotypes and cofactors) pathways were analysed using qPCR and immunochemical methods. PCB126 induced transcripts of ER and AhR signalling pathways that were variably influenced by protein synthesis and receptor inhibitors. CHX stimulated a coordinated recruitment of the proteasome complex, resulting in the ubiquitination and degradation of ER and AhR isoforms and downstream protein products. Interestingly, DMF produced differential effects on the AhR signalling pathway, in the presence or absence of PCB126. Overall, ER-hijacking by dioxin-like compounds and subsequent activation of ER responsive genes involves both receptor activation/deactivation and receptor-protein degradation/destabilization (stability). Given that the Per-AhR/Arnt-Sim homology sequence of transcription factors usually associate with each other to form heterodimers and bind the XRE or ERE sequences in the promoter regions of target genes to regulate their expression, the complete mechanism of interactions between dioxin-like and estrogenic compounds in vertebrate systems may require additional characterization.
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Affiliation(s)
- Martine H Gjernes
- Department of Biology, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
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Swedenborg E, Kotka M, Seifert M, Kanno J, Pongratz I, Rüegg J. The aryl hydrocarbon receptor ligands 2,3,7,8-tetrachlorodibenzo-p-dioxin and 3-methylcholanthrene regulate distinct genetic networks. Mol Cell Endocrinol 2012; 362:39-47. [PMID: 22634562 DOI: 10.1016/j.mce.2012.05.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 04/11/2012] [Accepted: 05/16/2012] [Indexed: 12/29/2022]
Abstract
The two estrogen receptor isoforms ERα and ERβ mediate biological effects of estrogens, but are also targets for endocrine disruptive chemicals (EDCs), compounds that interfere with hormonal signaling. 3-Methylcholanthrene (3-MC) and dioxin (TCDD) are EDCs and prototypical aryl hydrocarbon receptor (AhR) agonists, and can inhibit ER signaling. However, in contrast to TCDD, 3-MC gives rise to metabolites with estrogenic properties. We compared gene expression profiles in HepG2 cells after exposure to 3-MC, TCDD, and the synthetic estrogen diethylstilbestrol (DES). Interestingly, we observed little overlap between the genetic networks activated by 3-MC and TCDD, two compounds sometimes considered as interchangeable AhR ligands. Like DES, 3-MC induced a number of ER-regulated genes and lead to recruitment of ERα to the promoters of such genes. Interestingly, in contrast to DES, the estrogenic effects exerted by 3-MC were exclusively observed in ERα, but not in ERβ-expressing cells, suggesting ER isoform selectivity of 3-MC-derived metabolites.
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Affiliation(s)
- Elin Swedenborg
- Department of Biosciences and Nutrition, Karolinska Institutet, Hälsovägen 7, 141 83 Huddinge, Sweden
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Vikström Bergander L, Cai W, Klocke B, Seifert M, Pongratz I. Tryptamine serves as a proligand of the AhR transcriptional pathway whose activation is dependent of monoamine oxidases. Mol Endocrinol 2012; 26:1542-51. [PMID: 22865928 DOI: 10.1210/me.2011-1351] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The function of the aryl hydrocarbon receptor (AhR) in mediating the biological effect to environmental pollutants is well established. However, accumulated evidence indicates a wide range of physiological and pathological functions mediated by the AhR, suggesting the existence of endogenous AhR ligand(s). The nature of an AhR ligand remain elusive; however, it is known that the AhR is activated by several compounds, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin or the tryptophan photoproduct 6-formylindolo[3,2-b]carbazole. In this study, we show that physiological concentrations of tryptamine (TA) lead to induction of cytochrome P4501A1 transcription through an AhR-dependent mechanism. In addition, we show that activation of the AhR by TA requires a functional monoamino oxidase system, suggesting that TA acts as an AhR proligand possibly by converting to a high-affinity AhR ligand. Taken together, we show a possible mechanism, through which AhR signaling is activated by endogenous conversion of TA involving monoamine oxidases.
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Wang Y, Yang D, Chang A, Chan WK, Zhao B, Denison MS, Xue L. Synthesis of a ligand–quencher conjugate for the ligand binding study of the aryl hydrocarbon receptor using a FRET assay. Med Chem Res 2012. [DOI: 10.1007/s00044-011-9575-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Rabaglino MB, Richards E, Denslow N, Keller-Wood M, Wood CE. Genomics of estradiol-3-sulfate action in the ovine fetal hypothalamus. Physiol Genomics 2012; 44:669-77. [PMID: 22570439 DOI: 10.1152/physiolgenomics.00127.2011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
In fetal sheep during late gestation sulfoconjugated estrogens in plasma reach a concentration 40-100 times greater than unconjugated estrogens. The objective of the present study was to determine the genomics of estradiol-3-sulfate (E(2)S) action in the ovine fetal brain. The hypothesis was that E(2)S stimulates genes involved in the neuroendocrine pathways that direct or facilitate fetal development at the end of gestation. Four sets of chronically catheterized ovine twin fetuses were studied (gestational age: 120-127 days gestation) with one infused with E(2)S intracerebroventricularly (1 mg/day) and the other remaining untreated (control). After euthanasia, mRNA samples were extracted from fetal brains. Only hypothalamic samples were employed for this study given the important function of this brain region in the control of the hypothalamus-pituitary-adrenal axis. Microarray analysis was performed following the Agilent protocol for one-color 8 × 15 microarrays, designed for Ovis aries. A total of 363 known genes were significantly upregulated by the E(2)S treatment (P < 0.05). Network and enrichment analyses were performed using the Cytoscape/Bingo software, and the results validated by quantitative real-time PCR. The main overrepresented biological processes resulting from this analysis were feeding behavior, hypoxia response, and transforming growth factor signaling. Notably, the genes involved in the feeding behavior (neuropeptide Y and agouti-related protein) were the most strongly induced by the E(2)S treatment. In conclusion, E(2)S may be an important component of the mechanism for activating orexigenic, hypoxia responsiveness and neuroprotective pathways in the lamb as it approaches postnatal life.
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Affiliation(s)
- Maria Belen Rabaglino
- Department of Animal Sciences, University of Florida College of Agriculture and Life Sciences, Gainesville, Florida 32610-0274, USA
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Endler A, Chen L, Zhang J, Xu GT, Shibasaki F. Binding of the ERα and ARNT1 AF2 domains to exon 21 of the SRC1 isoform SRC1e is essential for estrogen- and dioxin-related transcription. J Cell Sci 2012; 125:2004-16. [PMID: 22328528 DOI: 10.1242/jcs.097246] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Steroid receptor co-activator 1 (SRC1) is a transcriptional co-activator of numerous transcription factors involving nuclear receptors. Aryl hydrocarbon receptor nuclear translocator 1 (ARNT1) is an obligatory transcriptional partner of the aryl hydrocarbon receptor (AhR) and hypoxia inducible factor-1α (HIF-1α), as well as a co-activator of estrogen receptors (ERs). To initiate transcription, the activation function 2 (AF2) domains of estrogen-activated ERs interact with LxxLL motifs in the nuclear receptor interaction domain (NID) of SRC1. Here we describe an estrogen and LxxLL domain-independent ERα AF2 binding to SRC1e exon 21. In addition, we found an AF2 domain in exon 16 of ARNT1 that also binds to SRC1e exon 21. Surprisingly, the interaction between SRC1e exon 21 and the AF2 domain of ERα functions as a crucial enhancer of estrogen-induced transcription. The binding of ARNT1 AF2 to SRC1e exon 21 enhances the transcriptional response to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), but the upregulation essentially depends on two cyclin destruction boxes (D-boxes), which are also located on exon 16 of ARNT1. Our findings reveal that a binding site for ERα and ARNT1 AF2 domains in the C-terminus of SRC1e upregulates estrogen- and TCDD-related responses in mammalian cells.
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Affiliation(s)
- Alexander Endler
- Department of Regenerative Medicine, and Stem Cell Research Center, Tongji University School of Medicine, Shanghai 200092, China.
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Wang Y, Li Y, Wang D, Li Y, Chang A, Chan WK. Suppression of the hypoxia inducible factor-1 function by redistributing the aryl hydrocarbon receptor nuclear translocator from nucleus to cytoplasm. Cancer Lett 2012; 320:111-21. [PMID: 22306343 DOI: 10.1016/j.canlet.2012.01.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 01/12/2012] [Accepted: 01/26/2012] [Indexed: 11/19/2022]
Abstract
The aryl hydrocarbon receptor nuclear translocator (ARNT) heterodimerizes with hypoxia inducible factor-1α (HIF-1α), followed by upregulation of genes that are essential for carcinogenesis. We utilized a novel peptide (Ainp1) to address whether the HIF-1α signaling could be suppressed by an ARNT-mediated mechanism. Ainp1 suppresses the HIF-1α-dependent luciferase expression in Hep3B cells and this suppression can be reversed by ARNT. Ainp1 reduces the interaction between ARNT and HIF-1α, suppresses the formation of the HIF-1 gel shift complex, and suppresses the ARNT recruitment to the vegf promoter. These effects are partly mediated by redistribution of the nuclear ARNT contents to the cytoplasm.
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Affiliation(s)
- Yu Wang
- Department of Pharmaceutics and Medicinal Chemistry, Thomas J. Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, CA 95211, USA
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Distinct roles for aryl hydrocarbon receptor nuclear translocator and ah receptor in estrogen-mediated signaling in human cancer cell lines. PLoS One 2012; 7:e29545. [PMID: 22235307 PMCID: PMC3250444 DOI: 10.1371/journal.pone.0029545] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Accepted: 11/30/2011] [Indexed: 01/01/2023] Open
Abstract
The activated AHR/ARNT complex (AHRC) regulates the expression of target genes upon exposure to environmental contaminants such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Importantly, evidence has shown that TCDD represses estrogen receptor (ER) target gene activation through the AHRC. Our data indicates that AHR and ARNT act independently from each other at non-dioxin response element sites. Therefore, we sought to determine the specific functions of AHR and ARNT in estrogen-dependent signaling in human MCF7 breast cancer and human ECC-1 endometrial carcinoma cells. Knockdown of AHR with siRNA abrogates dioxin-inducible repression of estrogen-dependent gene transcription. Intriguingly, knockdown of ARNT does not effect TCDD-mediated repression of estrogen-regulated transcription, suggesting that AHR represses ER function independently of ARNT. This theory is supported by the ability of the selective AHR modulator 3′,4′-dimethoxy-α-naphthoflavone (DiMNF) to repress estrogen-inducible transcription. Furthermore, basal and estrogen-activated transcription of the genes encoding cathepsin-D and pS2 are down-regulated in MCF7 cells but up-regulated in ECC-1 cells in response to loss of ARNT. These responses are mirrored at the protein level with cathepsin-D. Furthermore, knock-down of ARNT led to opposite but corresponding changes in estrogen-stimulated proliferation in both MCF7 and ECC-1 cells. We have obtained experimental evidence demonstrating a dioxin-dependent repressor function for AHR and a dioxin-independent co-activator/co-repressor function for ARNT in estrogen signalling. These results provide us with further insight into the mechanisms of transcription factor crosstalk and putative therapeutic targets in estrogen-positive cancers.
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Brunnberg S, Andersson P, Poellinger L, Hanberg A. The constitutively active Ah receptor (CA-AhR) mouse as a model for dioxin exposure - effects in reproductive organs. CHEMOSPHERE 2011; 85:1701-1706. [PMID: 22014662 DOI: 10.1016/j.chemosphere.2011.09.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2011] [Revised: 08/25/2011] [Accepted: 09/22/2011] [Indexed: 05/31/2023]
Abstract
The dioxin/aryl hydrocarbon receptor (AhR) mediates most toxic effects of dioxins. In utero/lactational exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) impairs fetal/neonatal development and the developing male reproductive tract are among the most sensitive tissues. TCDD causes antiestrogenic responses in rodent mammary gland and uterus and in human breast cancer cell lines in the presence of estrogen. Also, more recently an estrogen-like effect of TCDD/AhR has been suggested in the absence of estrogen. A transgenic mouse expressing a constitutively active AhR (CA-AhR) was developed as a model mimicking a situation of constant exposure to AhR agonists. Male and female reproductive tissues of CA-AhR mice were characterized for some of the effects commonly seen after dioxin exposure. Sexually mature CA-AhR female mice showed decreased uterus weight, while an uterotrophic assay in immature CA-AhR mice resulted in increased uterus weight. In immature mice, both TCDD-exposure and CA-AhR increased the expression of the estrogen receptor target gene Cathepsin D. When co-treated with 17β-estradiol no increase in Cathepsin D levels occurred in either TCDD-exposed or CA-AhR mice. In sexually mature male CA-AhR mice the weights of testis and ventral prostate were decreased and the epididymal sperm reserve was reduced. The results of the present study are in accordance with previous studies on dioxin-exposed rodents in that an activated AhR (here CA-AhR) leads to antiestrogenic effects in the presence of estrogen, but to estrogenic effects in the absence of estrogen. These results suggest the CA-AhR mouse model as a useful tool for studies of continuous low activity of the AhR from early development, resembling the human exposure situation.
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Affiliation(s)
- Sara Brunnberg
- Institute of Environmental Medicine, Karolinska Institutet, S-171 77 Stockholm, Sweden.
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Cai W, Kramarova TV, Berg P, Korbonits M, Pongratz I. The immunophilin-like protein XAP2 is a negative regulator of estrogen signaling through interaction with estrogen receptor α. PLoS One 2011; 6:e25201. [PMID: 21984905 PMCID: PMC3184960 DOI: 10.1371/journal.pone.0025201] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2011] [Accepted: 08/29/2011] [Indexed: 01/06/2023] Open
Abstract
XAP2 (also known as aryl hydrocarbon receptor interacting protein, AIP) is originally identified as a negative regulator of the hepatitis B virus X-associated protein. Recent studies have expanded the range of XAP2 client proteins to include the nuclear receptor family of transcription factors. In this study, we show that XAP2 is recruited to the promoter of ERα regulated genes like the breast cancer marker gene pS2 or GREB1 and negatively regulate the expression of these genes in MCF-7 cells. Interestingly, we show that XAP2 downregulates the E₂-dependent transcriptional activation in an estrogen receptor (ER) isoform-specific manner: XAP2 inhibits ERα but not ERβ-mediated transcription. Thus, knockdown of intracellular XAP2 levels leads to increased ERα activity. XAP2 proteins, carrying mutations in their primary structures, loose the ability of interacting with ERα and can no longer regulate ER target gene transcription. Taken together, this study shows that XAP2 exerts a negative effect on ERα transcriptional activity and may thus prevent ERα-dependent events.
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Affiliation(s)
- Wen Cai
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Tatiana V. Kramarova
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Petra Berg
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Marta Korbonits
- Endocrinology, Barts and the London School of Medicine, Queen Mary University of London, London, United Kingdom
| | - Ingemar Pongratz
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
- * E-mail:
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Denison MS, Soshilov AA, He G, DeGroot DE, Zhao B. Exactly the same but different: promiscuity and diversity in the molecular mechanisms of action of the aryl hydrocarbon (dioxin) receptor. Toxicol Sci 2011; 124:1-22. [PMID: 21908767 DOI: 10.1093/toxsci/kfr218] [Citation(s) in RCA: 567] [Impact Index Per Article: 43.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The Ah receptor (AhR) is a ligand-dependent transcription factor that mediates a wide range of biological and toxicological effects that result from exposure to a structurally diverse variety of synthetic and naturally occurring chemicals. Although the overall mechanism of action of the AhR has been extensively studied and involves a classical nuclear receptor mechanism of action (i.e., ligand-dependent nuclear localization, protein heterodimerization, binding of liganded receptor as a protein complex to its specific DNA recognition sequence and activation of gene expression), details of the exact molecular events that result in most AhR-dependent biochemical, physiological, and toxicological effects are generally lacking. Ongoing research efforts continue to describe an ever-expanding list of ligand-, species-, and tissue-specific spectrum of AhR-dependent biological and toxicological effects that seemingly add even more complexity to the mechanism. However, at the same time, these studies are also identifying and characterizing new pathways and molecular mechanisms by which the AhR exerts its actions and plays key modulatory roles in both endogenous developmental and physiological pathways and response to exogenous chemicals. Here we provide an overview of the classical and nonclassical mechanisms that can contribute to the differential sensitivity and diversity in responses observed in humans and other species following ligand-dependent activation of the AhR signal transduction pathway.
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Affiliation(s)
- Michael S Denison
- Department of Environmental Toxicology, University of California, Davis, California 95616, USA.
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Huang S, Lu F, Zhang Z, Yang X, Chen Y. The Role of Psychologic Stress-Induced Hypoxia-Inducible Factor-1α in Rat Experimental Periodontitis. J Periodontol 2011; 82:934-41. [DOI: 10.1902/jop.2010.100610] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Lam SH, Lee SGP, Lin CY, Thomsen JS, Fu PY, Murthy KRK, Li H, Govindarajan KR, Nick LCH, Bourque G, Gong Z, Lufkin T, Liu ET, Mathavan S. Molecular conservation of estrogen-response associated with cell cycle regulation, hormonal carcinogenesis and cancer in zebrafish and human cancer cell lines. BMC Med Genomics 2011; 4:41. [PMID: 21575170 PMCID: PMC3114699 DOI: 10.1186/1755-8794-4-41] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Accepted: 05/16/2011] [Indexed: 12/14/2022] Open
Abstract
Background The zebrafish is recognized as a versatile cancer and drug screening model. However, it is not known whether the estrogen-responsive genes and signaling pathways that are involved in estrogen-dependent carcinogenesis and human cancer are operating in zebrafish. In order to determine the potential of zebrafish model for estrogen-related cancer research, we investigated the molecular conservation of estrogen responses operating in both zebrafish and human cancer cell lines. Methods Microarray experiment was performed on zebrafish exposed to estrogen (17β-estradiol; a classified carcinogen) and an anti-estrogen (ICI 182,780). Zebrafish estrogen-responsive genes sensitive to both estrogen and anti-estrogen were identified and validated using real-time PCR. Human homolog mapping and knowledge-based data mining were performed on zebrafish estrogen responsive genes followed by estrogen receptor binding site analysis and comparative transcriptome analysis with estrogen-responsive human cancer cell lines (MCF7, T47D and Ishikawa). Results Our transcriptome analysis captured multiple estrogen-responsive genes and signaling pathways that increased cell proliferation, promoted DNA damage and genome instability, and decreased tumor suppressing effects, suggesting a common mechanism for estrogen-induced carcinogenesis. Comparative analysis revealed a core set of conserved estrogen-responsive genes that demonstrate enrichment of estrogen receptor binding sites and cell cycle signaling pathways. Knowledge-based and network analysis led us to propose that the mechanism involving estrogen-activated estrogen receptor mediated down-regulation of human homolog HES1 followed by up-regulation cell cycle-related genes (human homologs E2F4, CDK2, CCNA, CCNB, CCNE), is highly conserved, and this mechanism may involve novel crosstalk with basal AHR. We also identified mitotic roles of polo-like kinase as a conserved signaling pathway with multiple entry points for estrogen regulation. Conclusion The findings demonstrate the use of zebrafish for characterizing estrogen-like environmental carcinogens and anti-estrogen drug screening. From an evolutionary perspective, our findings suggest that estrogen regulation of cell cycle is perhaps one of the earliest forms of steroidal-receptor controlled cellular processes. Our study provides first evidence of molecular conservation of estrogen-responsiveness between zebrafish and human cancer cell lines, hence demonstrating the potential of zebrafish for estrogen-related cancer research.
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Affiliation(s)
- Siew Hong Lam
- Genome Institute of Singapore, #02-01Genome, 60 Biopolis Street, 138672 Singapore
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Lim W, Park Y, Cho J, Park C, Park J, Park YK, Park H, Lee Y. Estrogen receptor beta inhibits transcriptional activity of hypoxia inducible factor-1 through the downregulation of arylhydrocarbon receptor nuclear translocator. Breast Cancer Res 2011; 13:R32. [PMID: 21435239 PMCID: PMC3219195 DOI: 10.1186/bcr2854] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Revised: 12/12/2010] [Accepted: 03/24/2011] [Indexed: 02/08/2023] Open
Abstract
Introduction Estrogen receptor (ER) β is predicted to play an important role in prevention of breast cancer development and metastasis. We have shown previously that ERβ inhibits hypoxia inducible factor (HIF)-1α mediated transcription, but the mechanism by which ERβ works to exert this effect is not understood. Methods Vascular endothelial growth factor (VEGF) was measured in conditioned medium by enzyme-linked immunosorbent assays. Reverse transcription polymerase chain reaction (RT-PCR), Western blotting, immunoprecipitation, luciferase assays and chromatin immunoprecipitation (ChIP) assays were used to ascertain the implication of ERβ on HIF-1 function. Results In this study, we found that the inhibition of HIF-1 activity by ERβ expression was correlated with ERβ's ability to degrade aryl hydrocarbon receptor nuclear translocator (ARNT) via ubiquitination processes leading to the reduction of active HIF-1α/ARNT complexes. HIF-1 repression by ERβ was rescued by overexpression of ARNT as examined by hypoxia-responsive element (HRE)-driven luciferase assays. We show further that ERβ attenuated the hypoxic induction of VEGF mRNA by directly decreasing HIF-1α binding to the VEGF gene promoter. Conclusions These results show that ERβ suppresses HIF-1α-mediated transcription via ARNT down-regulation, which may account for the tumour suppressive function of ERβ.
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Affiliation(s)
- Wonchung Lim
- Department of Bioscience and Biotechnology, College of Life Science, Institute of Biotechnology, Sejong University, Kwangjingu, Kunjadong, Seoul 143-747, Korea
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Morozova T, Hackett J, Sedaghat Y, Sonnenfeld M. The Drosophila jing gene is a downstream target in the Trachealess/Tango tracheal pathway. Dev Genes Evol 2010; 220:191-206. [PMID: 21061019 DOI: 10.1007/s00427-010-0339-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Accepted: 10/08/2010] [Indexed: 11/28/2022]
Abstract
Primary branching in the Drosophila trachea is regulated by the Trachealess (Trh) and Tango (Tgo) basic helix-loop-helix-PAS (bHLH-PAS) heterodimers, the POU protein Drifter (Dfr)/Ventral Veinless (Vvl), and the Pointed (Pnt) ETS transcription factor. The jing gene encodes a zinc finger protein also required for tracheal development. Three Trh/Tgo DNA-binding sites, known as CNS midline elements, in 1.5 kb of jing 5′ cis-regulatory sequence (jing1.5) previously suggested a downstream role for jing in the pathway. Here, we show that jing is a direct downstream target of Trh/Tgo and that Vvl and Pnt are also involved in jing tracheal activation. In vivo lacZ enhancer detection assays were used to identify cis-regulatory elements mediating embryonic expression patterns of jing. A 2.8-kb jing enhancer (jing2.8) drove lacZ expression in all tracheal cell lineages, the CNS midline and Engrailed-positive segmental stripes, mimicking endogenous jing expression. A 1.3-kb element within jing2.8 drove expression that was restricted to Engrailed-positive CNS midline cells and segmental ectodermal stripes. Surprisingly, jing1.5-lacZ expression was restricted to tracheal fusion cells despite the presence of consensus DNA-binding sites for bHLH-PAS, ETS, and POU domain transcription factors. Given the absence of Trh/Tgo DNA-binding sites in the jing1.3 enhancer, these results are consistent with previous observations suggesting a combinatorial basis to Trh-/Tgo-mediated transcriptional regulation in the trachea.
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Affiliation(s)
- Tatiana Morozova
- Faculty of Medicine, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
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