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Rabkin SW, Wong CN. Epigenetics in Heart Failure: Role of DNA Methylation in Potential Pathways Leading to Heart Failure with Preserved Ejection Fraction. Biomedicines 2023; 11:2815. [PMID: 37893188 PMCID: PMC10604152 DOI: 10.3390/biomedicines11102815] [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: 08/23/2023] [Revised: 09/21/2023] [Accepted: 09/26/2023] [Indexed: 10/29/2023] Open
Abstract
This review will focus on epigenetic modifications utilizing the DNA methylation mechanism, which is potentially involved in the pathogenesis of heart failure with preserved ejection fraction (HFpEF). The putative pathways of HFpEF will be discussed, specifically myocardial fibrosis, myocardial inflammation, sarcoplasmic reticulum Ca2+-ATPase, oxidative-nitrosative stress, mitochondrial and metabolic defects, as well as obesity. The relationship of HFpEF to aging and atrial fibrillation will be examined from the perspective of DNA methylation.
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Affiliation(s)
- Simon W. Rabkin
- Department of Medicine, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
- Division of Cardiology, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
| | - Chenille N. Wong
- Department of Medicine, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
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2
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Vannitamby A, Saad MI, Aloe C, Wang H, Kumar B, Vlahos R, Selemidis S, Irving L, Steinfort D, Jenkins BJ, Bozinovski S. Aspirin-Triggered Resolvin D1 Reduces Proliferation and the Neutrophil to Lymphocyte Ratio in a Mutant KRAS-Driven Lung Adenocarcinoma Model. Cancers (Basel) 2021; 13:cancers13133224. [PMID: 34203378 PMCID: PMC8268479 DOI: 10.3390/cancers13133224] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 06/23/2021] [Accepted: 06/24/2021] [Indexed: 12/20/2022] Open
Abstract
Simple Summary Aspirin-triggered resolvin D1 (AT-RvD1) is biosynthesised by leukocytes as a mechanism to resolve inflammation during infection and/or injury. Emerging studies reveal that AT-RvD1 also has anti-cancer properties associated with stimulating macrophage-mediated clearance of tumour debris. No study to date has investigated how AT-RvD1 influences the neutrophil to lymphocyte ratio (NLR) in lung cancer, an established marker of poor prognosis. The biosynthesis of AT-RvD1 is dependent on the ALOX5 gene, and we reveal that ALOX5 mRNA expression was markedly reduced in lung adenocarcinoma tumours. We next utilised an oncogenic KrasG12D lung adenocarcinoma mouse model to investigate the efficacy of AT-RvD1 in vivo. We show for the first time that AT-RvD1 reduces tumour growth in the lungs of KrasG12D mice and alters the immune landscape in tumours by reducing the NLR. Abstract Tumour-associated neutrophils (TANs) can support tumour growth by suppressing cytotoxic lymphocytes. AT-RvD1 is an eicosanoid that can antagonise neutrophil trafficking instigated by ALX/FPR2 ligands such as serum amyloid A (SAA). We aimed to establish whether SAA and ALOX5 expression associates with TANs and investigate the immunomodulatory actions of AT-RvD1 in vivo. MPO-positive neutrophils were quantified in tumour blocks from lung adenocarcinoma (n = 48) and control tissue (n = 20) by IHC. Tumour expression of SAA and ALOX5 were analysed by RTqPCR and an oncogenic KrasG12D lung adenocarcinoma mouse model was used to investigate the in vivo efficacy of AT-RvD1 treatment. ALOX5 expression was markedly reduced in lung adenocarcinoma tumours. The SAA/ALOX5 ratio strongly correlated with TANs and was significantly increased in tumours harbouring an oncogenic KRAS mutation. AT-RvD1 treatment reduced tumour growth in KrasG12D mice, which was accompanied by suppressed cellular proliferation within parenchymal lesions. In addition, AT-RvD1 significantly reduced the neutrophil to lymphocyte ratio (NLR), an established prognostic marker of poor survival in adenocarcinoma. This study identifies a novel molecular signature whereby elevated levels of SAA relative to ALOX5 favour accumulation of TANs. Furthermore, the ALOX5/5-LO enzymatic product, AT-RvD1, markedly reduced the NLR and suppressed tumour growth in KrasG12D mice.
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Affiliation(s)
- Amanda Vannitamby
- School of Health & Biomedical Sciences, RMIT University, Bundoora 3083, Australia; (A.V.); (C.A.); (H.W.); (R.V.); (S.S.)
| | - Mohamed I. Saad
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton 3168, Australia; (M.I.S.); (B.J.J.)
- Department of Molecular Translational Science, School of Clinical Sciences, Monash University, Clayton 3168, Australia
| | - Christian Aloe
- School of Health & Biomedical Sciences, RMIT University, Bundoora 3083, Australia; (A.V.); (C.A.); (H.W.); (R.V.); (S.S.)
| | - Hao Wang
- School of Health & Biomedical Sciences, RMIT University, Bundoora 3083, Australia; (A.V.); (C.A.); (H.W.); (R.V.); (S.S.)
| | - Beena Kumar
- Department of Anatomical Pathology, Monash Health, Clayton 3168, Australia;
| | - Ross Vlahos
- School of Health & Biomedical Sciences, RMIT University, Bundoora 3083, Australia; (A.V.); (C.A.); (H.W.); (R.V.); (S.S.)
| | - Stavros Selemidis
- School of Health & Biomedical Sciences, RMIT University, Bundoora 3083, Australia; (A.V.); (C.A.); (H.W.); (R.V.); (S.S.)
| | - Louis Irving
- Department of Respiratory Medicine, Royal Melbourne Hospital, Parkville 3050, Australia; (L.I.); (D.S.)
| | - Daniel Steinfort
- Department of Respiratory Medicine, Royal Melbourne Hospital, Parkville 3050, Australia; (L.I.); (D.S.)
| | - Brendan J. Jenkins
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton 3168, Australia; (M.I.S.); (B.J.J.)
- Department of Molecular Translational Science, School of Clinical Sciences, Monash University, Clayton 3168, Australia
| | - Steven Bozinovski
- School of Health & Biomedical Sciences, RMIT University, Bundoora 3083, Australia; (A.V.); (C.A.); (H.W.); (R.V.); (S.S.)
- Correspondence:
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3
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da Costa Loureiro L, da Costa Loureiro L, Gabriel-Junior EA, Zambuzi FA, Fontanari C, Sales-Campos H, Frantz FG, Faccioli LH, Sorgi CA. Pulmonary surfactant phosphatidylcholines induce immunological adaptation of alveolar macrophages. Mol Immunol 2020; 122:163-172. [PMID: 32361419 DOI: 10.1016/j.molimm.2020.04.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 03/26/2020] [Accepted: 04/13/2020] [Indexed: 12/14/2022]
Abstract
Pulmonary surfactant plays an important role in lung surface tension, defense against invading pathogens, and immune response. Furthermore, alveolar macrophages (AM) that comprise the front line of immune defense against inhaled microorganisms are covered by a layer of pulmonary fluid. Phosphatidylcholines (PCs), including unsaturated lipids such as 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), are the most prevalent phospholipids in pulmonary surfactant. POPC reacts with ozone to produce 1-palmitoyl-2-(9-oxo-nonanoyl)-sn-glycero-3-phosphocholine (PONPC), a soluble mediator that initiates an inflammatory reaction in the lungs. However, the modulatory effects of POPC and PONPC on biology and activity of AM remain inconclusive. The exposure of AM (cell line AMJ2-C11) to POPC and PONPC was not directly related to the production of inflammatory mediators. However, AM, pre-incubated with POPC or PONPC, showed enhanced response after lipopolysaccharide (LPS) stimulation, and increased the production of nitric oxide and cytokines. This phenomenon was also observed for classical-polarized macrophages (M1). This increment on the production of inflammatory mediators was not associated with macrophage polarization, but with up-regulation of Tlr4 and Myd88 gene expression, which was in accordance with the adaptation of immune cells. This observation was confirmed by the histone acetylation epigenetic pathway. In contrast to the priming effect of POPC on AM activity, a harmful immune response, induced on incubation with PONPC, improved prostaglandin E2 (PGE2) formation, resulting in diminished bacterial phagocytosis. Additionally, PONPC induced production of CXCL1/KC, which potentially mediates neutrophil recruitment and enhances tissue inflammation. These results disclosed another dynamic mechanism by which pulmonary surfactant lipids (natural or oxidized) primed macrophage activity, thus affecting lung host defense.
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Affiliation(s)
- Luma da Costa Loureiro
- Instituto de Ciências Biológicas, Programa de Pós-Graduação em Imunologia Básica e Aplicada (PPGIBA), Universidade Federal do Amazonas (UFAM), Manaus, Amazonas, Brazil; Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Luana da Costa Loureiro
- Instituto de Ciências Biológicas, Programa de Pós-Graduação em Imunologia Básica e Aplicada (PPGIBA), Universidade Federal do Amazonas (UFAM), Manaus, Amazonas, Brazil; Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Edson Alves Gabriel-Junior
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Fabiana Albani Zambuzi
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Caroline Fontanari
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Helioswilton Sales-Campos
- Departamento de Biociências e Tecnologia, Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Fabiani Gai Frantz
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Lúcia Helena Faccioli
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Carlos Arterio Sorgi
- Instituto de Ciências Biológicas, Programa de Pós-Graduação em Imunologia Básica e Aplicada (PPGIBA), Universidade Federal do Amazonas (UFAM), Manaus, Amazonas, Brazil; Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil.
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4
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Monga J, Subramani D, Bharathan A, Ghosh J. Pharmacological and genetic targeting of 5-lipoxygenase interrupts c-Myc oncogenic signaling and kills enzalutamide-resistant prostate cancer cells via apoptosis. Sci Rep 2020; 10:6649. [PMID: 32313135 PMCID: PMC7171151 DOI: 10.1038/s41598-020-62845-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 03/17/2020] [Indexed: 11/09/2022] Open
Abstract
Much of the morbidity and mortality due to prostate cancer happen because of castration-resistant prostate cancer (CRPC) which invariably develops after anti-androgenic therapy. FDA-approved enzalutamide is commonly prescribed for CRPC which works by blocking androgen receptor function. However, even after initial good response, enzalutamide-resistant prostate cancer (ERPC) develops which eventually leads to widespread metastasis. Management of ERPC is extremely difficult because available therapeutic regimen cannot effectively kill and eliminate ERPC cells. Though the mechanism behind enzalutamide-resistance is not properly understood, over-activation of c-Myc has been found to be a common event which plays an important role in the maintenance and progression of ERPC phenotype. However, direct-targeting of c-Myc poses special problem because of its non-enzymatic nature and certain amount of c-Myc activity is needed by non-cancer cells as well. Thus, c-Myc has emerged as an elusive target which needs to be managed by novel agents and strategies in a cancer-specific way. We investigated the effects of pharmacological and genetic inhibition of 5-lipoxygenase (5-Lox) on cell proliferation, apoptosis and invasive potential of enzalutamide-resistant prostate cancer cells. Transcriptional activity of c-Myc was analyzed by DNA-binding, luciferase-assays, and expression of c-Myc-target genes. We found that 5-Lox regulates c-Myc signaling in enzalutamide-resistant prostate cancer cells and inhibition of 5-Lox by Quiflapon/MK591 or shRNA interrupts oncogenic c-Myc signaling and kills ERPC cells by triggering caspase-mediated apoptosis. Interestingly, MK591 does not affect normal, non-cancer cells in the same experimental conditions. Our findings indicate that inhibition of 5-Lox may emerge as a promising new approach to effectively kill ERPC cells sparing normal cells and suggest that development of a long-term curative therapy of prostate cancer may be possible by killing and eliminating ERPC cells with suitable 5-Lox-inhibitors.
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Affiliation(s)
- Jitender Monga
- Vattikuti Urology Institute, Henry Ford Health System, Detroit, MI, 48202, United States
| | - Dhatchayini Subramani
- Vattikuti Urology Institute, Henry Ford Health System, Detroit, MI, 48202, United States
| | - Ajay Bharathan
- Vattikuti Urology Institute, Henry Ford Health System, Detroit, MI, 48202, United States
| | - Jagadananda Ghosh
- Vattikuti Urology Institute, Henry Ford Health System, Detroit, MI, 48202, United States.
- Henry Ford Cancer Institute, Henry Ford Health System, Detroit, MI, 48202, United States.
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5
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Schlag K, Steinhilber D, Karas M, Sorg BL. Analysis of proximal ALOX5 promoter binding proteins by quantitative proteomics. FEBS J 2020; 287:4481-4499. [PMID: 32096311 DOI: 10.1111/febs.15259] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 10/15/2019] [Accepted: 02/23/2020] [Indexed: 01/01/2023]
Abstract
5-Lipoxygenase (5-LO) is the initial enzyme in the biosynthesis of leukotrienes, which are mediators involved in pathophysiological conditions such as asthma and certain cancer types. Knowledge of proteins involved in 5-LO pathway regulation, including gene regulatory proteins, is needed to evaluate all options for therapeutic intervention in these diseases. Here, we present a mass spectrometric screening of ALOX5 promoter-interacting proteins, obtained by DNA pulldown and label-free quantitative mass spectrometry. Protein preparations from myeloid and B-lymphocytic cell lines were screened for promoter DNA interactors. Through statistical analysis, 66 proteins were identified as specific ALOX5 promotor binding proteins. Among those, the 15 most likely candidates for a prominent role in ALOX5 gene regulation are the known ALOX5 interactors Sp1 and Sp3, the related factor Sp2, two Krüppel-like factors (KLF13 and KLF16) and six other zinc finger proteins (MAZ, PRDM10, VEZF1, ZBTB7A, ZNF281 and ZNF579). Intriguingly, we also identified two helicases (BLM and DHX36) and the proteins hnRNPD and hnRNPK, which are, together with the protein MAZ, known to interact with DNA G-quadruplex structures. As G-quadruplexes are implicated in gene regulation, spectroscopic and antibody-based methods were used to confirm their presence within the GC-rich sequence of the ALOX5 promoter. In summary, we have systematically characterized the interactome of the ALOX5 promoter, identifying several zinc finger proteins as novel potential ALOX5 gene regulators. Further, we have shown that the ALOX5 promoter can form DNA G-quadruplex structures, which may play a functional role in ALOX5 gene regulation.
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Affiliation(s)
- Katharina Schlag
- Institute of Pharmaceutical Chemistry/ZAFES, Goethe-University, Frankfurt am Main, Germany
| | - Dieter Steinhilber
- Institute of Pharmaceutical Chemistry/ZAFES, Goethe-University, Frankfurt am Main, Germany
| | - Michael Karas
- Institute of Pharmaceutical Chemistry/ZAFES, Goethe-University, Frankfurt am Main, Germany
| | - Bernd L Sorg
- Institute of Pharmaceutical Chemistry/ZAFES, Goethe-University, Frankfurt am Main, Germany
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6
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Poirier SJ, Boudreau LH, Flamand N, Surette ME. LPS induces ALOX5 promoter activation and 5-lipoxygenase expression in human monocytic cells. Prostaglandins Leukot Essent Fatty Acids 2020; 154:102078. [PMID: 32120263 DOI: 10.1016/j.plefa.2020.102078] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 02/15/2020] [Accepted: 02/18/2020] [Indexed: 11/24/2022]
Abstract
5-lipoxygenase (5-LO), coded by the ALOX5 gene, is expressed in leukocytes and catalyzes the formation of leukotrienes, pro-inflammatory lipid mediators. Leukotrienes are central to immune responses, but are also involved in inflammatory disorders and 5-LO expression is associated with leukemia stem cell survival. It is therefore important to understand mechanisms that control 5-LO expression. This study investigated the control of 5-LO expression and leukotriene biosynthesis following the maturation of human monocytic cells. MonoMac-1 (MM1) and THP-1 cells were incubated for up to 72 h with or without LPS and TGF-β. LPS, but not TGF-β, increased CD14 expression in both MM1 and THP-1 cells. Incubation with LPS (100 ng/ml) and TGF-β (1 ng/ml) synergistically increased the capacity of MM1 cells to produce 5-LO products from undetectable levels to 40±5 pmol/106 cells. 5-LO product biosynthesis in THP-1 cells increased 25-fold. A synergistic effect of LPS and TGF-β was measured with increases in 5-LO mRNA of 54- and 13-fold in MM1 and THP-1 cells, respectively. 5-LO protein expression increased significantly in both MM1 and THP-1 cells. ALOX5 promoter activity was significantly elevated >2-fold in both cell lines following LPS treatment, but TGF-β was without effect. The main 5-LO products were cysteinyl-leukotrienes, however LPS and TGF-β did not impact on the capacity of the cells to metabolize leukotriene A4. Overall, this study demonstrates that receptor-mediated stimulation of MM1 and THP-1 cells by LPS is associated with increased 5-LO expression. This represents a new mechanism by which leukotriene biosynthesis can be modulated by pathological agents.
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Affiliation(s)
- Samuel J Poirier
- Département de chimie et biochimie, Université de Moncton, Moncton, NB, E1A 3E9, Canada; Centre de recherche de l'Institut universitaire de cardiologie et pneumologie de Québec-Université Laval, Département de médecine, Faculté de médecine, Université Laval, Québec City, QC, G1V 4G5, Canada
| | - Luc H Boudreau
- Département de chimie et biochimie, Université de Moncton, Moncton, NB, E1A 3E9, Canada
| | - Nicolas Flamand
- Centre de recherche de l'Institut universitaire de cardiologie et pneumologie de Québec-Université Laval, Département de médecine, Faculté de médecine, Université Laval, Québec City, QC, G1V 4G5, Canada
| | - Marc E Surette
- Département de chimie et biochimie, Université de Moncton, Moncton, NB, E1A 3E9, Canada.
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7
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Häfner AK, Kahnt AS, Steinhilber D. Beyond leukotriene formation—The noncanonical functions of 5-lipoxygenase. Prostaglandins Other Lipid Mediat 2019; 142:24-32. [DOI: 10.1016/j.prostaglandins.2019.03.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 03/14/2019] [Accepted: 03/25/2019] [Indexed: 01/17/2023]
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8
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Di Meco A, Li JG, Praticò D. Dissecting the Role of 5-Lipoxygenase in the Homocysteine-Induced Alzheimer's Disease Pathology. J Alzheimers Dis 2019; 62:1337-1344. [PMID: 29254095 PMCID: PMC5869997 DOI: 10.3233/jad-170700] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Alzheimer’s disease (AD) affects over 40 million patients around the world and poses a huge economic burden on society since no effective therapy is available yet. While the cause(s) for the most common sporadic form of the disease are still obscure, lifestyle and different environmental factors have emerged as modulators of AD susceptibility. Hyperhomocysteinemia (HHCY), a condition of high circulating levels of homocysteine, is an independent but modifiable risk factor for AD. Studies in AD mouse models have linked HHCY with memory impairment, amyloidosis, tau pathology, synaptic dysfunction, and neuroinflammation. However, the exact mechanism by which HHCY affects AD pathogenesis is unclear. The 5-lipoxygenase (5LO) is a protein upregulated in postmortem AD brains and plays a functional role in AD pathogenesis. Recently, in vitro and in vivo studies showed that HHCY effects on amyloid-β and tau pathology, synapse and memory impairments are dependent on the activation of the 5LO enzymatic pathway, since its genetic absence or pharmacological inhibition prevents them. HHCY induces 5LO gene upregulation by lowering the methylation of its promoter, which results in increased translation and transcription of its mRNA. Based on these findings, we propose that epigenetic modification of 5LO represents the missing biological link between HHCY and AD pathogenesis, and for this reason it represents a viable therapeutic target to prevent AD development in individuals bearing this risk factor.
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Affiliation(s)
- Antonio Di Meco
- Alzheimer's Center at Temple, Lewis Katz School of Medicine Temple University, Philadelphia, PA, USA
| | - Jian-Guo Li
- Alzheimer's Center at Temple, Lewis Katz School of Medicine Temple University, Philadelphia, PA, USA
| | - Domenico Praticò
- Alzheimer's Center at Temple, Lewis Katz School of Medicine Temple University, Philadelphia, PA, USA
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9
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Sarveswaran S, Varma NRS, Morisetty S, Ghosh J. Inhibition of 5-lipoxygenase downregulates stemness and kills prostate cancer stem cells by triggering apoptosis via activation of c-Jun N-terminal kinase. Oncotarget 2019; 10:424-436. [PMID: 30728896 PMCID: PMC6355185 DOI: 10.18632/oncotarget.13422] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 11/07/2016] [Indexed: 11/25/2022] Open
Abstract
The cancer stem cell (CSC) concept suggests that neoplastic clones are maintained exclusively by a rare group of cells possessed with stem cell properties. CSCs are characterized by features that include self-renewal, pluripotency and tumorigenicity, and are thought to be solely responsible for tumor recurrence and metastasis. A hierarchically organized CSC model is becoming increasingly evident for various types of cancer, including prostate cancer. The CD44 (+), CD133 (+) cell subpopulations were isolated from human prostate tumors which exhibit stem-like properties showing therapeutic-resistance, capacity of self-renewal, and exact recapitulation of the original tumor in vivo. Thus, an important challenge is to find measures to eliminate these cancer stem cells, which will stop tumor growth and prevent disease-recurrence. However, knowledge about molecular features critical for the survival of prostate cancer stem cells (PCSC) is meager. Here we report that inhibition of 5-lipoxygenase (5-Lox) by shRNA or MK591 dramatically kills PCSC by inducing apoptosis, suggesting that 5-Lox plays an essential role in the survival of PCSC. Interestingly, MK591 treatment decreases protein levels and inhibits transcriptional activities of Nanog and c-Myc. Since Nanog and c-Myc play important roles as stemness factors, our findings indicate that the 5-Lox activity plays a causal role in maintaining prostate cancer stemness via regulation of Nanog and c-Myc, and suggest that further exploration of 5-Lox-mediated signaling in PCSC may lead to development of novel, target-based, durable strategies to effectively block development and growth of prostate tumors, and prevent prostate cancer recurrence.
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Affiliation(s)
- Sivalokanathan Sarveswaran
- Vattikuti Urology Institute and Josephine Ford Cancer Center, Henry Ford Health System, Detroit, MI 48202, USA
| | - Nadimpalli R S Varma
- Vattikuti Urology Institute and Josephine Ford Cancer Center, Henry Ford Health System, Detroit, MI 48202, USA
| | - Shravan Morisetty
- Vattikuti Urology Institute and Josephine Ford Cancer Center, Henry Ford Health System, Detroit, MI 48202, USA
| | - Jagadananda Ghosh
- Vattikuti Urology Institute and Josephine Ford Cancer Center, Henry Ford Health System, Detroit, MI 48202, USA
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10
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Saul MJ, Groher F, Hegewald AB, Müller-McNicoll M, Marschalek R, Suess B, Steinhilber D. TGFβ/SMAD signalling modulates MLL and MLL-AF4 mediated 5-lipoxygenase promoter activation. Prostaglandins Other Lipid Mediat 2017; 133:60-67. [DOI: 10.1016/j.prostaglandins.2017.07.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 06/28/2017] [Accepted: 07/31/2017] [Indexed: 01/11/2023]
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11
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Li JG, Barrero C, Merali S, Praticò D. Genetic absence of ALOX5 protects from homocysteine-induced memory impairment, tau phosphorylation and synaptic pathology. Hum Mol Genet 2017; 26:1855-1862. [PMID: 28334897 DOI: 10.1093/hmg/ddx088] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 03/02/2017] [Indexed: 11/13/2022] Open
Abstract
Elevated level of homocysteine (Hcy) is considered a risk factor for neurodegenerative diseases, but the mechanisms remain to be established. Because high Hcy is associated with an up-regulation of the ALOX5 gene product, the 5Lipoxygenase (5LO), herein we investigated whether this activation is responsible for the Hcy effect on neurodegeneration or is a secondary event. To reach this goal, wild type mice and mice genetically deficient for 5LO were assessed after being exposed to a diet known to significantly increase brain levels of Hcy. Confirming compliance with the dietary regimen, we found that by the end of the study brain levels of Hcy were significantly increase in both groups. However, diet-induced high Hcy resulted in a significant increase in Aβ, tau phosphorylation, neuroinflammation, synaptic pathology and memory impairment in control mice, but not in mice lacking ALOX5.Taken together our findings demonstrate that the up-regulation of the ALOX5 gene pathway is responsible for the development of the biochemical and behavioral sequelae of high Hcy brain levels in the context of a neurodegenerative phenotype. They provide critical support that this gene and its expressed protein are viable therapeutic targets to prevent the onset, or delay neurodegenerative events in subjects exposed to this risk factor.
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Affiliation(s)
- Jian-Guo Li
- Department of Pharmacology and Center for Translational Medicine, Lewis Katz School of Medicine
| | - Carlos Barrero
- Department of Pharmaceutical Sciences, Temple University Philadelphia, PA 19140, USA
| | - Salim Merali
- Department of Pharmaceutical Sciences, Temple University Philadelphia, PA 19140, USA
| | - Domenico Praticò
- Department of Pharmacology and Center for Translational Medicine, Lewis Katz School of Medicine
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12
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Li JG, Barrero C, Merali S, Praticò D. Five lipoxygenase hypomethylation mediates the homocysteine effect on Alzheimer's phenotype. Sci Rep 2017; 7:46002. [PMID: 28383037 PMCID: PMC5382538 DOI: 10.1038/srep46002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 03/07/2017] [Indexed: 12/11/2022] Open
Abstract
Environmental and genetic risk factors are implicated in the pathogenesis of Alzheimer’s disease (AD). However, how they interact and influence its pathogenesis remains to be investigated. High level of homocysteine (Hcy) is an AD risk factor and associates with an up-regulation of the ALOX5 gene. In the current paper we investigated whether this activation is responsible for the Hcy effect on the AD phenotype and the mechanisms involved. Triple transgenic mice were randomized to receive regular chow diet, a diet deficient in folate and B vitamins (Diet), which results in high Hcy, or the Diet plus zileuton, a specific ALOX5 inhibitor, for 7 months. Compared with controls, Diet-fed mice had a significant increase in Hcy levels, memory and learning deficits, up-regulation of the ALOX5 pathway, increased Aβ levels, tau phosphorylation, and synaptic pathology, which were absent in mice treated with zileuton. In vivo and vitro studies demonstrated that the mechanism responsible was the hypomethylation of the ALOX5 promoter. Our findings demonstrate that the up-regulation of the ALOX5 is responsible for the Hcy-dependent worsening of the AD phenotype in a relevant mouse model of the disease. The discovery of this previously unknown cross-talk between these two pathways could afford novel therapeutic opportunities for treating or halting AD.
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Affiliation(s)
- Jian-Guo Li
- Department of Pharmacology and Center for Translational Medicine, Lewis Katz School of Medicine, Temple University Philadelphia, PA 19140, USA
| | - Carlos Barrero
- Department of Pharmaceutical Sciences, Temple University Philadelphia, PA 19140, USA
| | - Salim Merali
- Department of Pharmaceutical Sciences, Temple University Philadelphia, PA 19140, USA
| | - Domenico Praticò
- Department of Pharmacology and Center for Translational Medicine, Lewis Katz School of Medicine, Temple University Philadelphia, PA 19140, USA
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Li J, Barrero C, Gupta S, Kruger WD, Merali S, Praticò D. Homocysteine modulates 5-lipoxygenase expression level via DNA methylation. Aging Cell 2017; 16:273-280. [PMID: 27896923 PMCID: PMC5334532 DOI: 10.1111/acel.12550] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/27/2016] [Indexed: 12/02/2022] Open
Abstract
Elevated levels of homocysteinemia (Hcy), a risk factor for late-onset Alzheimer's disease (AD), have been associated with changes in cell methylation. Alzheimer's disease is characterized by an upregulation of the 5-lipoxygenase (5LO), whose promoter is regulated by methylation. However, whether Hcy activates 5LO enzymatic pathway by influencing the methylation status of its promoter remains unknown. Brains from mice with high Hcy were assessed for the 5LO pathway and neuronal cells exposed to Hcy implemented to study the mechanism(s) regulating 5LO expression levels and the effect on amyloid β formation. Diet- and genetically induced high Hcy resulted in 5LO protein and mRNA upregulation, which was associated with a significant increase of the S-adenosylhomocysteine (SAH)/S-adenosylmethionine ratio, and reduced DNA methyltrasferases and hypomethylation of 5-lipoxygenase DNA. In vitro studies confirmed these results and demonstrated that the mechanism involved in the Hcy-dependent 5LO activation and amyloid β formation is DNA hypomethylation secondary to the elevated levels of SAH. Taken together these findings represent the first demonstration that Hcy directly influences 5LO expression levels and establish a previously unknown cross talk between these two pathways, which is highly relevant for AD pathogenesis. The discovery of such a novel link not only provides new mechanistic insights in the neurobiology of Hcy, but most importantly new therapeutic opportunities for the individuals bearing this risk factor for the disease.
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Affiliation(s)
- Jian‐Guo Li
- Department of Pharmacology and Center for Translational MedicineLewis Katz School of MedicinePhiladelphiaPA19140USA
| | - Carlos Barrero
- Department of Pharmaceutical SciencesTemple University PhiladelphiaPhiladelphiaPA19140USA
| | - Sapna Gupta
- Cancer Biology Program Fox Chase Cancer CenterTemple University PhiladelphiaPhiladelphiaPA19140USA
| | - Warren D. Kruger
- Cancer Biology Program Fox Chase Cancer CenterTemple University PhiladelphiaPhiladelphiaPA19140USA
| | - Salim Merali
- Department of Pharmaceutical SciencesTemple University PhiladelphiaPhiladelphiaPA19140USA
| | - Domenico Praticò
- Department of Pharmacology and Center for Translational MedicineLewis Katz School of MedicinePhiladelphiaPA19140USA
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Cardani A, Boulton A, Kim TS, Braciale TJ. Alveolar Macrophages Prevent Lethal Influenza Pneumonia By Inhibiting Infection Of Type-1 Alveolar Epithelial Cells. PLoS Pathog 2017; 13:e1006140. [PMID: 28085958 PMCID: PMC5268648 DOI: 10.1371/journal.ppat.1006140] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 01/26/2017] [Accepted: 12/19/2016] [Indexed: 12/21/2022] Open
Abstract
The Influenza A virus (IAV) is a major human pathogen that produces significant morbidity and mortality. To explore the contribution of alveolar macrophages (AlvMΦs) in regulating the severity of IAV infection we employed a murine model in which the Core Binding Factor Beta gene is conditionally disrupted in myeloid cells. These mice exhibit a selective deficiency in AlvMΦs. Following IAV infection these AlvMΦ deficient mice developed severe diffuse alveolar damage, lethal respiratory compromise, and consequent lethality. Lethal injury in these mice resulted from increased infection of their Type-1 Alveolar Epithelial Cells (T1AECs) and the subsequent elimination of the infected T1AECs by the adaptive immune T cell response. Further analysis indicated AlvMΦ-mediated suppression of the cysteinyl leukotriene (cysLT) pathway genes in T1AECs in vivo and in vitro. Inhibition of the cysLT pathway enzymes in a T1AECs cell line reduced the susceptibility of T1AECs to IAV infection, suggesting that AlvMΦ-mediated suppression of this pathway contributes to the resistance of T1AECs to IAV infection. Furthermore, inhibition of the cysLT pathway enzymes, as well as blockade of the cysteinyl leukotriene receptors in the AlvMΦ deficient mice reduced the susceptibility of their T1AECs to IAV infection and protected these mice from lethal infection. These results suggest that AlvMΦs may utilize a previously unappreciated mechanism to protect T1AECs against IAV infection, and thereby reduce the severity of infection. The findings further suggest that the cysLT pathway and the receptors for cysLT metabolites represent potential therapeutic targets in severe IAV infection. A primary feature of lethal influenza infection is viral pneumonia. Influenza viral pneumonia is caused by the direct infection of alveolar epithelial cells, which subsequently causes extensive alveolar inflammation and injury. Clinically this pathology manifests as diffuse alveolar damage leading to acute respiratory distress syndrome. As alveolar macrophages are positioned in the alveoli, they are the ideally localized to be a first-line of defense against alveolar invading pathogens, such as influenza. To explore the contribution of alveolar macrophages to the development of lethal influenza pneumonia, we generated a novel mouse model with a selective deficiency in alveolar macrophages. As a result of the alveolar macrophage deficiency, these mice developed severe diffuse alveolar damage and lethal respiratory compromise after influenza infection. Lethal injury resulted from increased infection of type-1 alveolar epithelial cells, and the elimination of these infected cells by effector T cells. Further analysis indicated that in order to render type 1 cells resistant to influenza infection, alveolar macrophages suppress leukotrieneD4 production and autocrine-signaling in type 1 cells. These results suggest that alveolar macrophages play a previously unappreciated role in protecting type 1 alveolar epithelial cells against IAV infection, and thus the severity of infection.
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Affiliation(s)
- Amber Cardani
- Beirne B. Carter Center for Immunology Research, University of Virginia, Charlottesville, Virginia, United States of America
- Department of Microbiology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Adam Boulton
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, United States of America
| | - Taeg S. Kim
- Beirne B. Carter Center for Immunology Research, University of Virginia, Charlottesville, Virginia, United States of America
- Department of Pathology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Thomas J. Braciale
- Beirne B. Carter Center for Immunology Research, University of Virginia, Charlottesville, Virginia, United States of America
- Department of Microbiology, University of Virginia, Charlottesville, Virginia, United States of America
- Department of Pathology, University of Virginia, Charlottesville, Virginia, United States of America
- * E-mail:
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15
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Ahmad K, Scholz B, Capelo R, Schweighöfer I, Kahnt AS, Marschalek R, Steinhilber D. AF4 and AF4-MLL mediate transcriptional elongation of 5-lipoxygenase mRNA by 1, 25-dihydroxyvitamin D3. Oncotarget 2016; 6:25784-800. [PMID: 26329759 PMCID: PMC4694866 DOI: 10.18632/oncotarget.4703] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 07/10/2015] [Indexed: 12/22/2022] Open
Abstract
The human 5-lipoxygenase (5-LO), encoded by the ALOX5 gene, is the key enzyme in the formation of pro-inflammatory leukotrienes. ALOX5 gene transcription is strongly stimulated by calcitriol (1α, 25-dihydroxyvitamin D3) and TGFβ (transforming growth factor-β). Here, we investigated the influence of MLL (activator of transcript initiation), AF4 (activator of transcriptional elongation) as well as of the leukemogenic fusion proteins MLL-AF4 (ectopic activator of transcript initiation) and AF4-MLL (ectopic activator of transcriptional elongation) on calcitriol/TGFβ-dependent 5-LO transcript elongation. We present evidence that the AF4 complex directly interacts with the vitamin D receptor (VDR) and promotes calcitriol-dependent ALOX5 transcript elongation. Activation of transcript elongation was strongly enhanced by the AF4-MLL fusion protein but was sensitive to Flavopiridol. By contrast, MLL-AF4 displayed no effect on transcriptional elongation. Furthermore, HDAC class I inhibitors inhibited the ectopic effects caused by AF4-MLL on transcriptional elongation, suggesting that HDAC class I inhibitors are potential therapeutics for the treatment of t(4;11)(q21;q23) leukemia.
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Affiliation(s)
- Khalil Ahmad
- Institute of Pharmaceutical Chemistry / ZAFES, Goethe University Frankfurt, Frankfurt, Germany
| | - Bastian Scholz
- Institute of Pharmaceutical Biology / ZAFES, Goethe University Frankfurt, Frankfurt, Germany
| | - Ricardo Capelo
- Institute of Pharmaceutical Chemistry / ZAFES, Goethe University Frankfurt, Frankfurt, Germany
| | - Ilona Schweighöfer
- Institute of Pharmaceutical Chemistry / ZAFES, Goethe University Frankfurt, Frankfurt, Germany
| | - Astrid Stefanie Kahnt
- Institute of Pharmaceutical Chemistry / ZAFES, Goethe University Frankfurt, Frankfurt, Germany
| | - Rolf Marschalek
- Institute of Pharmaceutical Biology / ZAFES, Goethe University Frankfurt, Frankfurt, Germany
| | - Dieter Steinhilber
- Institute of Pharmaceutical Chemistry / ZAFES, Goethe University Frankfurt, Frankfurt, Germany
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16
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5-Lipoxygenase is a direct p53 target gene in humans. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2015; 1849:1003-16. [DOI: 10.1016/j.bbagrm.2015.06.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 05/19/2015] [Accepted: 06/07/2015] [Indexed: 11/18/2022]
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17
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Sarveswaran S, Ghosh R, Morisetty S, Ghosh J. MK591, a second generation leukotriene biosynthesis inhibitor, prevents invasion and induces apoptosis in the bone-invading C4-2B human prostate cancer cells: implications for the treatment of castration-resistant, bone-metastatic prostate cancer. PLoS One 2015; 10:e0122805. [PMID: 25875826 PMCID: PMC4398363 DOI: 10.1371/journal.pone.0122805] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 02/13/2015] [Indexed: 11/18/2022] Open
Abstract
Castration-resistant prostate cancer (CRPC) is a major clinical challenge for which no cure is currently available primarily because of the lack of proper understanding about appropriate molecular target(s). Previously we observed that inhibition of 5-lipoxygenase (5-Lox) activity induces apoptosis in some types of prostate cancer cells, suggesting an important role of 5-Lox in the viability of prostate cancer cells. However, nothing is known about the role of 5-Lox in the survival of castration-resistant, metastatic prostate cancer cells. Thus, we tested the effects of MK591, a second-generation, specific inhibitor of 5-Lox activity, on the viability and metastatic characteristics of CRPC cells. We observed that MK591 effectively kills the bone-invading C4-2B human prostate cancer cells (which bear characteristics of CRPC), but does not affect normal, non-cancer fibroblasts (which do not express 5-Lox) in the same experimental conditions. We also observed that MK591 dramatically inhibits the in vitro invasion and soft-agar colony formation of C4-2B cells. Interestingly, we found that treatment with MK591 dramatically down-regulates the expression of c-Myc and its targets at sub-lethal doses. In light of frequent over-activation of c-Myc in a spectrum of aggressive cancers (including CRPC), and the challenges associated with inhibition of c-Myc (because of its non-enzymatic nature), our novel findings of selective killing, and blockade of invasive and soft-agar colony-forming abilities of the castration-resistant, bone-metastatic C4-2B prostate cancer cells by MK591, open up a new avenue to attack CRPC cells for better management of advanced prostate cancer while sparing normal, non-cancer body cells.
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Affiliation(s)
| | - Ritisha Ghosh
- Department of Urology, Henry Ford Health System, Detroit, MI 48202, United States of America
| | - Shravan Morisetty
- Department of Urology, Henry Ford Health System, Detroit, MI 48202, United States of America
| | - Jagadananda Ghosh
- Department of Urology, Henry Ford Health System, Detroit, MI 48202, United States of America; Josephine Ford Cancer Center, Henry Ford Health System, Detroit, MI 48202, United States of America
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18
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Ahmad K, Katryniok C, Scholz B, Merkens J, Löscher D, Marschalek R, Steinhilber D. Inhibition of class I HDACs abrogates the dominant effect of MLL-AF4 by activation of wild-type MLL. Oncogenesis 2014; 3:e127. [PMID: 25402609 PMCID: PMC4259963 DOI: 10.1038/oncsis.2014.39] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Revised: 09/14/2014] [Accepted: 09/30/2014] [Indexed: 12/15/2022] Open
Abstract
The ALOX5 gene encodes 5-lipoxygenase (5-LO), a key enzyme of inflammatory reactions, which is transcriptionally activated by trichostatin A (TSA). Physiologically, 5-LO expression is induced by calcitriol and/or transforming growth factor-β. Regulation of 5-LO mRNA involves promoter activation and elongation control within the 3'-portion of the ALOX5 gene. Here we focused on the ALOX5 promoter region. Transcriptional initiation was associated with an increase in histone H3 lysine 4 trimethylation in a TSA-inducible manner. Therefore, we investigated the effects of the MLL (mixed lineage leukemia) protein and its derivatives, MLL-AF4 and AF4-MLL, respectively. MLL-AF4 was able to enhance ALOX5 promoter activity by 47-fold, which was further stimulated when either vitamin D receptor and retinoid X receptor or SMAD3/SMAD4 were co-transfected. In addition, we investigated several histone deacetylase inhibitors (HDACi) in combination with gene knockdown experiments (HDAC1-3, MLL). We were able to demonstrate that a combined inhibition of HDAC1-3 induces ALOX5 promoter activity in an MLL-dependent manner. Surprisingly, a constitutive activation of ALOX5 by MLL-AF4 was inhibited by class I HDAC inhibitors, by relieving inhibitory functions deriving from MLL.Conversely, a knockdown of MLL increased the effects mediated by MLL-AF4. Thus, HDACi treatment seems to switch 'inactive MLL' into 'active MLL' and overwrites the dominant functions deriving from MLL-AF4.
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Affiliation(s)
- K Ahmad
- Institute of Pharmaceutical Chemistry/ZAFES, Goethe University Frankfurt, Frankfurt, Germany
| | - C Katryniok
- Institute of Pharmaceutical Chemistry/ZAFES, Goethe University Frankfurt, Frankfurt, Germany
| | - B Scholz
- Institute of Pharmaceutical Biology/ZAFES, Goethe University Frankfurt, Frankfurt, Germany
| | - J Merkens
- Institute of Pharmaceutical Biology/ZAFES, Goethe University Frankfurt, Frankfurt, Germany
| | - D Löscher
- Institute of Pharmaceutical Biology/ZAFES, Goethe University Frankfurt, Frankfurt, Germany
| | - R Marschalek
- Institute of Pharmaceutical Biology/ZAFES, Goethe University Frankfurt, Frankfurt, Germany
| | - D Steinhilber
- Institute of Pharmaceutical Chemistry/ZAFES, Goethe University Frankfurt, Frankfurt, Germany
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19
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Roos J, Oancea C, Heinssmann M, Khan D, Held H, Kahnt AS, Capelo R, la Buscató E, Proschak E, Puccetti E, Steinhilber D, Fleming I, Maier TJ, Ruthardt M. 5-Lipoxygenase Is a Candidate Target for Therapeutic Management of Stem Cell–like Cells in Acute Myeloid Leukemia. Cancer Res 2014; 74:5244-55. [DOI: 10.1158/0008-5472.can-13-3012] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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20
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Porter KM, Kang BY, Adesina SE, Murphy TC, Hart CM, Sutliff RL. Chronic hypoxia promotes pulmonary artery endothelial cell proliferation through H2O2-induced 5-lipoxygenase. PLoS One 2014; 9:e98532. [PMID: 24906007 PMCID: PMC4048210 DOI: 10.1371/journal.pone.0098532] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 05/05/2014] [Indexed: 01/11/2023] Open
Abstract
Pulmonary Hypertension (PH) is a progressive disorder characterized by endothelial dysfunction and proliferation. Hypoxia induces PH by increasing vascular remodeling. A potential mediator in hypoxia-induced PH development is arachidonate 5-Lipoxygenase (ALOX5). While ALOX5 metabolites have been shown to promote pulmonary vasoconstriction and endothelial cell proliferation, the contribution of ALOX5 to hypoxia-induced proliferation remains unknown. We hypothesize that hypoxia exposure stimulates HPAEC proliferation by increasing ALOX5 expression and activity. To test this, human pulmonary artery endothelial cells (HPAEC) were cultured under normoxic (21% O2) or hypoxic (1% O2) conditions for 24-, 48-, or 72 hours. In a subset of cells, the ALOX5 inhibitor, zileuton, or the 5-lipoxygenase activating protein inhibitor, MK-886, was administered during hypoxia exposure. ALOX5 expression was measured by qRT-PCR and western blot and HPAEC proliferation was assessed. Our results demonstrate that 24 and 48 hours of hypoxia exposure have no effect on HPAEC proliferation or ALOX5 expression. Seventy two hours of hypoxia significantly increases HPAEC ALOX5 expression, hydrogen peroxide (H2O2) release, and HPAEC proliferation. We also demonstrate that targeted ALOX5 gene silencing or inhibition of the ALOX5 pathway by pharmacological blockade attenuates hypoxia-induced HPAEC proliferation. Furthermore, our findings indicate that hypoxia-induced increases in cell proliferation and ALOX5 expression are dependent on H2O2 production, as administration of the antioxidant PEG-catalase blocks these effects and addition of H2O2 to HPAEC promotes proliferation. Overall, these studies indicate that hypoxia exposure induces HPAEC proliferation by activating the ALOX5 pathway via the generation of H2O2.
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Affiliation(s)
- Kristi M. Porter
- Emory University School of Medicine/Atlanta Veterans Affairs Medical Center, Department of Pulmonary, Allergy and Critical Care Medicine, Atlanta, Georgia, United States of America
| | - Bum-Yong Kang
- Emory University School of Medicine/Atlanta Veterans Affairs Medical Center, Department of Pulmonary, Allergy and Critical Care Medicine, Atlanta, Georgia, United States of America
| | - Sherry E. Adesina
- Emory University School of Medicine/Atlanta Veterans Affairs Medical Center, Department of Pulmonary, Allergy and Critical Care Medicine, Atlanta, Georgia, United States of America
| | - Tamara C. Murphy
- Emory University School of Medicine/Atlanta Veterans Affairs Medical Center, Department of Pulmonary, Allergy and Critical Care Medicine, Atlanta, Georgia, United States of America
| | - C. Michael Hart
- Emory University School of Medicine/Atlanta Veterans Affairs Medical Center, Department of Pulmonary, Allergy and Critical Care Medicine, Atlanta, Georgia, United States of America
| | - Roy L. Sutliff
- Emory University School of Medicine/Atlanta Veterans Affairs Medical Center, Department of Pulmonary, Allergy and Critical Care Medicine, Atlanta, Georgia, United States of America
- * E-mail:
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21
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Weiss RM, Miller JD, Heistad DD. Fibrocalcific aortic valve disease: opportunity to understand disease mechanisms using mouse models. Circ Res 2013; 113:209-22. [PMID: 23833295 DOI: 10.1161/circresaha.113.300153] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Studies in vitro and in vivo continue to identify complex-regulated mechanisms leading to overt fibrocalcific aortic valve disease (FCAVD). Assessment of the functional impact of those processes requires careful studies of models of FCAVD in vivo. Although the genetic basis for FCAVD is unknown for most patients with FCAVD, several disease-associated genes have been identified in humans and mice. Some gene products which regulate valve development in utero also protect against fibrocalcific disease during postnatal aging. Valve calcification can occur via processes that resemble bone formation. But valve calcification can also occur by nonosteogenic mechanisms, such as formation of calcific apoptotic nodules. Anticalcific interventions might preferentially target either osteogenic or nonosteogenic calcification. Although FCAVD and atherosclerosis share several risk factors and mechanisms, there are fundamental differences between arteries and the aortic valve, with respect to disease mechanisms and responses to therapeutic interventions. Both innate and acquired immunity are likely to contribute to FCAVD. Angiogenesis is a feature of inflammation, but may also contribute independently to progression of FCAVD, possibly by actions of pericytes that are associated with new blood vessels. Several therapeutic interventions seem to be effective in attenuating the development of FCAVD in mice. Therapies which are effective early in the course of FCAVD, however, are not necessarily effective in established disease.
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Affiliation(s)
- Robert M Weiss
- Division of Cardiovascular Medicine, University of Iowa Carver College of Medicine, Iowa City, IA, USA.
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22
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Pufahl L, Katryniok C, Schnur N, Sorg BL, Metzner J, Grez M, Steinhilber D. Trichostatin A induces 5-lipoxygenase promoter activity and mRNA expression via inhibition of histone deacetylase 2 and 3. J Cell Mol Med 2012; 16:1461-73. [PMID: 21883892 PMCID: PMC3823215 DOI: 10.1111/j.1582-4934.2011.01420.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The 5-lipoxygenase (5-LO) is the key enzyme in the formation of leukotrienes. We have previously shown that the histone deacetylase (HDAC) inhibitor trichostatin A (TSA) activates 5-LO transcription via recruitment of Sp1, Sp3 and RNA polymerase II to the proximal promoter. To identify the HDACs involved in the regulation of 5-LO promoter activity isoform-specific HDAC inhibitors were applied. 5-LO promoter activity and mRNA expression were up-regulated by the class I HDAC inhibitors apicidin and MS-275 but not by class II inhibitors. Knockdown of HDAC 1, 2 and 3 revealed that HDAC2 and HDAC3 but not HDAC1 is involved in the up-regulation of 5-LO mRNA expression. To analyse the chromatin modifications at the 5-LO promoter associated with HDAC inhibition, the time course of 5-LO mRNA induction by trichostatin A was investigated and the concomitant changes in histone modifications at the 5-LO promoter in HL-60, U937 and Mono Mac6 cells were determined. Chromatin immunoprecipitation analysis revealed that trichostatin A increases acetylation of histones H3 and H4 at the 5-LO core promoter in HL-60 and U937 cells whereas no significant changes were observed in Mono Mac6 cells. The appearance of H3 and H4 acetylation preceded the 5-LO mRNA induction whereas in all three cell lines, induction of 5-LO mRNA expression correlated with histone H3 lysine 4 trimethylation (H3K4me3), a marker for transcriptional activity of gene promoters.
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Affiliation(s)
- Laura Pufahl
- Institute of Pharmaceutical Chemistry/ZAFES, Goethe University Frankfurt, Frankfurt, Germany
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23
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Kummer NT, Nowicki TS, Azzi JP, Reyes I, Iacob C, Xie S, Swati I, Darzynkiewicz Z, Gotlinger KH, Suslina N, Schantz S, Tiwari RK, Geliebter J. Arachidonate 5 lipoxygenase expression in papillary thyroid carcinoma promotes invasion via MMP-9 induction. J Cell Biochem 2012; 113:1998-2008. [PMID: 22253131 DOI: 10.1002/jcb.24069] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Arachidonate 5-lipoxygenase (ALOX5) expression and activity has been implicated in tumor pathogenesis, yet its role in papillary thyroid carcinoma (PTC) has not been characterized. ALOX5 protein and mRNA were upregulated in PTC compared to matched, normal thyroid tissue, and ALOX5 expression correlated with invasive tumor histopathology. Evidence suggests that PTC invasion is mediated through the induction of matrix metalloproteinases (MMPs) that can degrade and remodel the extracellular matrix (ECM). A correlation between MMP-9 and ALOX5 protein expression was established by immunohistochemical analysis of PTC and normal thyroid tissues using a tissue array. Transfection of ALOX5 into a PTC cell line (BCPAP) increased MMP-9 secretion and cell invasion across an ECM barrier. The ALOX5 product, 5(S)-hydroxyeicosatetraenoic acid also increased MMP-9 protein expression by BCPAP in a dose-dependent manner. Inhibitors of MMP-9 and ALOX5 reversed ALOX5-enhanced invasion. Here we describe a new role for ALOX5 as a mediator of invasion via MMP-9 induction; this ALOX5/MMP9 pathway represents a new avenue in the search for functional biomarkers and/or potential therapeutic targets for aggressive PTC.
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Affiliation(s)
- Nicolas T Kummer
- Department of Microbiology & Immunology, New York Medical College, Valhalla, New York 10595, USA
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24
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Pettigrew KA, Armstrong RN, Colyer HAA, Zhang SD, Rea IM, Jones RE, Baird DM, Mills KI. Differential TERT promoter methylation and response to 5-aza-2'-deoxycytidine in acute myeloid leukemia cell lines: TERT expression, telomerase activity, telomere length, and cell death. Genes Chromosomes Cancer 2012; 51:768-80. [PMID: 22517724 DOI: 10.1002/gcc.21962] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Accepted: 03/22/2012] [Indexed: 11/06/2022] Open
Abstract
The catalytic subunit of human telomerase (TERT) is highly expressed in cancer cells, and correlates with complex cytogenetics and disease severity in acute myeloid leukemia (AML). The TERT promoter is situated within a large CpG island, suggesting that expression is methylation-sensitive. Studies suggest a correlation between hypermethylation and TERT overexpression. We investigated the relationship between TERT promoter methylation and expression and telomerase activity in human leukemia and lymphoma cell lines. DAC-induced demethylation and cell death were observed in all three cell lines, as well as telomere shortening in HL-60 cells. DAC treatment reduced TERT expression and telomerase activity in OCI/AML3 and HL-60 cells, but not in U937 cells. Control U937 cells expressed lower levels of TERT mRNA, carried a highly methylated TERT core promoter, and proved more resistant to DAC-induced repression of TERT expression and cell death. AML patients had significantly lower methylation levels at several CpGs than "well elderly" individuals. This study, the first to investigate the relationship between TERT methylation and telomerase activity in leukemia cells, demonstrated a differential methylation pattern and response to DAC in three AML cell lines. We suggest that, although DAC treatment reduces TERT expression and telomerase activity, this is unlikely to occur via direct demethylation of the TERT promoter. However, further investigations on the regions spanning CpGs 7-12 and 14-16 may reveal valuable information regarding transcriptional regulation of TERT.
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Affiliation(s)
- Kerry A Pettigrew
- Centre for Cancer Research and Cell Biology, Queens University Belfast, Belfast BT9 7BL, UK.
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Nagy E, Bäck M. Epigenetic regulation of 5-lipoxygenase in the phenotypic plasticity of valvular interstitial cells associated with aortic valve stenosis. FEBS Lett 2012; 586:1325-9. [PMID: 22616993 DOI: 10.1016/j.febslet.2012.03.039] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Revised: 03/14/2012] [Accepted: 03/20/2012] [Indexed: 11/17/2022]
Abstract
Valvular interstitial cells (VICs) are of mesenchymal origin and may differentiate into immune-like cells. This phenotypic plasticity is a key feature of aortic valve stenosis, but the role of epigenetic mechanisms has not previously been explored. Here we compared normal and calcified human aortic valve tissue. Calcified tissue exhibited decreased DNA-methylation in the promoter of the gene encoding the proinflammatory enzyme 5-lipoxygenase (5-LO), accompanied by increased 5-LO mRNA levels. Treatment of cultured VICs with the DNA methyltransferase inhibitor: 5-Aza-2'-deoxycytidine increased 5-LO mRNA levels and leukotriene production. These findings provide a first piece of evidence for epigenetic modifications of VICs in valvular heart disease.
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Affiliation(s)
- Edit Nagy
- Department of Medicine, Karolinska Institutet, Stockholm, Sweden
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26
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Haeggström JZ, Funk CD. Lipoxygenase and leukotriene pathways: biochemistry, biology, and roles in disease. Chem Rev 2011; 111:5866-98. [PMID: 21936577 DOI: 10.1021/cr200246d] [Citation(s) in RCA: 591] [Impact Index Per Article: 45.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Jesper Z Haeggström
- Department of Medical Biochemistry and Biophysics, Division of Chemistry 2, Karolinska Institutet, S-171 77 Stockholm, Sweden.
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27
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Li W, Li X, Wang W, Li X, Tan Y, Yi M, Yang J, McCarthy JB, Xiong W, Wu M, Ma J, Su B, Zhang Z, Liao Q, Xiang B, Li G. NOR1 is an HSF1- and NRF1-regulated putative tumor suppressor inactivated by promoter hypermethylation in nasopharyngeal carcinoma. Carcinogenesis 2011; 32:1305-14. [PMID: 21803736 DOI: 10.1093/carcin/bgr174] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Promoter hypermethylation-mediated silencing of tumor suppressor genes (TSGs) is a hallmark of oncogenesis. Oxidored-nitro domain-containing protein 1 (NOR1) is a candidate TSG that is downregulated in nasopharyngeal carcinoma (NPC). In the present study, we identified a functional NOR1 promoter that is regulated by heat shock factor 1 and nuclear respiratory factor 1. The promoter is located within a CpG island. Hypermethylation of this CpG island was found in NPC tissue samples and cancer cell lines, whereas no aberrant promoter methylation was detected in non-cancerous nasopharyngeal tissue samples or normal nasopharyngeal epithelial cells. Treatment of NPC 6-10B cells and leukemia HL60 cells with 5'-aza-2'-deoxycytidine increased endogenous levels of NOR1 messenger RNA. Ectopic expression of NOR1 in NPC HNE1 cells inhibited tumor cell colony formation and viability. These findings suggest that promoter hypermethylation may participate in transcriptional inactivation of the NOR1 gene in NPC. Frequent epigenetic inactivation of the NOR1 gene in NPC suggests that it may be a critical tumor suppressor involved in the development of NPC.
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Affiliation(s)
- Wenjuan Li
- Cancer Research Institute, Xiangya School of Medicine, Central South University, Xiangya Road, Changsha, Hunan 410078, China
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Moore EE. Claude H. Organ, Jr. memorial lecture: splanchnic hypoperfusion provokes acute lung injury via a 5-lipoxygenase-dependent mechanism. Am J Surg 2011; 200:681-9. [PMID: 21146002 DOI: 10.1016/j.amjsurg.2010.05.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Revised: 05/31/2010] [Accepted: 05/31/2010] [Indexed: 01/01/2023]
Abstract
Postinjury multiple organ failure (MOF) is the net result of a dysfunctional immune response to injury characterized by a hyperactive innate system and a suppressed adaptive system. Acute lung injury (ALI) is the first clinical manifestation of organ failure, followed by renal and hepatic dysfunction. Circulatory shock is integral in the early pathogenesis of MOF, and the gut has been invoked as the motor of MOF. Mesenteric lymph is recognized as the mechanistic link between splanchnic ischemia/reperfusion and distant organ dysfunction, but the specific mediators remain to be defined. Current evidence suggests the lipid fraction of postshock mesenteric lymph is central in the etiology of ALI. Specifically, our recent work suggests that intestinal phospholipase A2 generated arachidonic acid and its subsequent 5-lipoxygenase products are essential in the pathogenesis of ALI. Proteins conveyed via postshock mesenteric lymph also may have an important role. Elucidating these mediators and the timing of their participation in pulmonary inflammation is critical in translating our current knowledge to new therapeutic strategies at the bedside.
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Affiliation(s)
- Ernest E Moore
- Department of Surgery, University of Colorado Denver, Denver, CO 80204, USA.
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29
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Fischer AS, Metzner J, Steinbrink SD, Ulrich S, Angioni C, Geisslinger G, Steinhilber D, Maier TJ. 5-Lipoxygenase inhibitors induce potent anti-proliferative and cytotoxic effects in human tumour cells independently of suppression of 5-lipoxygenase activity. Br J Pharmacol 2010; 161:936-49. [PMID: 20860670 DOI: 10.1111/j.1476-5381.2010.00915.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND AND PURPOSE Certain 5-lipoxygenase (5-LO) inhibitors exhibit anti-carcinogenic activities against 5-LO overexpressing tumour types and cultured tumour cells. It has been proposed therefore that 5-LO products significantly contribute to tumour cell proliferation. To date, the relationship between the inhibitory mechanisms of 5-LO inhibitors, which vary widely, and tumour cell viability has not been evaluated. This study addresses the anti-proliferative and cytotoxic potency of a number of 5-LO inhibitors with different inhibitory mechanisms in 5-LO-positive and 5-LO-negative tumour cells. EXPERIMENTAL APPROACH Cell viability was measured by the WST-1 assay; cell proliferation was assessed using the bromodeoxyuridine (BrdU) incorporation assay. Cell death was analysed by annexin V staining, Western blot analysis of PARP (poly ADP-ribose polymerase) cleavage and a cytotoxicity assay. 5-LO product formation was quantified by a 5-LO activity assay. KEY RESULTS The common 5-LO inhibitors AA-861, Rev-5901 and MK-886 induced cytotoxic and anti-proliferative effects in 5-LO-positive Capan-2 pancreatic cancer cells; BWA4C and CJ-13,610 only caused anti-proliferative effects, while zileuton failed to impair cell viability. Moreover, the concentrations of the 5-LO inhibitors required to induce anti-proliferation and cytotoxicity highly exceeded those for suppression of 5-LO. Supplementation with mitogenic 5-LO products failed to protect Capan-2 cells from the effects of 5-LO inhibitors. Finally, the cytotoxic and anti-proliferative 5-LO inhibitors also potently reduced the viability of 5-LO-deficient tumour cell lines (HeLa, Panc-1 and U937). CONCLUSIONS AND IMPLICATIONS Certain 5-LO inhibitors cause cytotoxic and anti-proliferative effects independently of suppression of 5-LO activity. Thus, the role of 5-LO overexpression in tumour cell viability remains unclear and requires further elucidation.
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Affiliation(s)
- A S Fischer
- Institute of Pharmaceutical Chemistry/ZAFES, Goethe-University, Frankfurt/Main, Germany
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30
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Boudreau LH, Bertin J, Robichaud PP, Laflamme M, Ouellette RJ, Flamand N, Surette ME. Novel 5‐lipoxygenase isoforms affect the biosynthesis of 5‐lipoxygenase products. FASEB J 2010; 25:1097-105. [DOI: 10.1096/fj.10-173856] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Luc H. Boudreau
- Département de Chimie et Biochimie Université de Moncton Moncton New Brunswick Canada
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec Departement de Medecine et Faculté de Médecine Université Laval Québec Canada
| | - Jonathan Bertin
- Département de Chimie et Biochimie Université de Moncton Moncton New Brunswick Canada
| | - Philippe P. Robichaud
- Département de Chimie et Biochimie Université de Moncton Moncton New Brunswick Canada
| | - Mark Laflamme
- Atlantic Cancer Research Institute Moncton New Brunswick Canada
- Department of Fisheries and Oceans Canada Moncton New Brunswick Canada
| | | | - Nicolas Flamand
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec Departement de Medecine et Faculté de Médecine Université Laval Québec Canada
| | - Marc E. Surette
- Département de Chimie et Biochimie Université de Moncton Moncton New Brunswick Canada
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31
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Chen H, Dzitoyeva S, Manev H. 5-Lipoxygenase in mouse cerebellar Purkinje cells. Neuroscience 2010; 171:383-9. [PMID: 20851170 DOI: 10.1016/j.neuroscience.2010.09.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Revised: 09/09/2010] [Accepted: 09/11/2010] [Indexed: 10/19/2022]
Abstract
It has been suggested that the enzymatic pathway of 5-lipoxygenase (5-LOX) influences brain functioning and pathobiology. The mRNAs for both the enzyme 5-LOX and its activating protein FLAP have been found in the cerebellum. In this work, we investigated the cellular expression of 5-LOX in the adult mouse cerebellar cortex. We used the in situ mRNA hybridization assay, immunocytochemistry, laser capture microdissection, and our previously developed method for assaying the DNA methylation status of a putative mouse 5-LOX promoter. Since both 5-LOX mRNA in situ hybridization signal and FLAP immunoreactivity co-localize with calbindin 28 kD immunoreactivity (a Purkinje cell marker) but not with S-100β immunoreactivity (a Bergmann glia marker), the suggestion is that the 5-LOX pathway is expressed in cerebellar Purkinje cells. We found that methylation in the sites targeted by methylation-sensitive restriction endonucleases AciI and HinP1I but not BstUI and HpaII was greater in DNA samples obtained from a high-5-LOX-expressing cerebellar region (Purkinje cells) versus a low-5-LOX-expressing region (the molecular cell layer), suggesting a possible epigenetic contribution to the cell-specific 5-LOX expression in the cerebellum. We propose that Purkinje cell-localized 5-LOX and FLAP expression may be involved in the cerebellar synthesis of leukotrienes and/or could influence the Dicer-mediated microRNA formation and processes of neuroplasticity.
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Affiliation(s)
- H Chen
- The Psychiatric Institute, Department of Psychiatry, University of Illinois at Chicago, Chicago, IL 60612, USA
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32
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Zhang Y, Bao YL, Wu Y, Yu CL, Sun Y, Li YX. Identification and characterization of the human SLC5A8 gene promoter. ACTA ACUST UNITED AC 2010; 196:124-32. [PMID: 20082847 DOI: 10.1016/j.cancergencyto.2009.09.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Accepted: 09/08/2009] [Indexed: 12/11/2022]
Abstract
The human SLC5A8 gene is a tumor suppressor. Its silencing may contribute to the carcinogenesis and progression of various tumors, which makes this gene an attractive molecular marker and a potential target for diagnosis and therapy. Little is known about transcriptional mechanisms controlling SLC5A8 gene expression. To better understand the molecular mechanisms regulating SLC5A8 expression, we characterized the 5'-regulatory region and a part of exon 1. Luciferase reporter assays of deletion mutants of SLC5A8 promoter demonstrated that a 295-bp region is essential for the basal promoter activity of the SLC5A8 gene. Further analysis indicated that the CCAAT boxes and GC boxes were involved in positive regulation of SLC5A8 promoter. Overexpression of two transcription factors, CCAAT/enhancer binding protein beta (C/EBPbeta) and specific transcription factor 1 (Sp1), upregulated the activities of the human SLC5A8 promoter and protein expression, suggesting that both C/EBPbeta and Sp1 transcription factors might have functions in SLC5A8 transcription. Taken together, our results elucidate the mechanism underlying the regulation of SLC5A8 gene transcription and also define a novel regulatory sequence that may be used to increase expression of the SLC5A8 gene in cancer gene therapy.
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Affiliation(s)
- Yu Zhang
- National Engineering Laboratory for Druggable Gene and Protein Screening, Northeast Normal University, Changchun 130024, China
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33
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5-Lipoxygenase DNA methylation and mRNA content in the brain and heart of young and old mice. Neural Plast 2009; 2009:209596. [PMID: 20052386 PMCID: PMC2801004 DOI: 10.1155/2009/209596] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Revised: 09/14/2009] [Accepted: 10/01/2009] [Indexed: 11/18/2022] Open
Abstract
The expression of 5-lipoxygenase (5-LOX) is affected by aging and regulated by epigenetic mechanisms including DNA methylation. We used methylation-sensitive restriction endonucleases (AciI, BstUI, HpaII, and HinP1I) to assess 5-LOX DNA methylation in brain and heart tissue samples from young (2 months) and old (22 months) mice. We also measured mRNA content for 5-LOX and the DNA methyltransferases DNMT1 and DNMT3a. In young mice, the 5-LOX mRNA content was significantly greater in the heart compared to the brain; 5-LOX DNA methylation was lower, except in the AciI assay in which it was higher in the heart. Aging decreased 5-LOX mRNA content in the heart and increased it in the brain. Aging also increased 5-LOX DNA methylation and this effect was site- (i.e., enzyme) and tissue-specific. Generally, DNMT1 and DNMT3a mRNA content was lower in the brain regions compared to the heart; the only effect of aging was observed in the mRNA content of DNMT3a, which was decreased in the heart of old mice. These results indicate a complex tissue-specific and aging-dependent interplay between the DNA methylation system and 5-LOX mRNA content. Interpretation of this data must take into account that the tissue samples contained a mixture of various cell types.
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34
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Stoffers KL, Sorg BL, Seuter S, Rau O, Rådmark O, Steinhilber D. Calcitriol upregulates open chromatin and elongation markers at functional vitamin D response elements in the distal part of the 5-lipoxygenase gene. J Mol Biol 2009; 395:884-96. [PMID: 19837082 DOI: 10.1016/j.jmb.2009.10.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Revised: 10/08/2009] [Accepted: 10/09/2009] [Indexed: 11/18/2022]
Abstract
5-Lipoxygenase (5-LO) gene expression is strongly upregulated during induction of myeloid cell differentiation by 1alpha,25-dihydroxyvitamin D(3) (calcitriol) and transforming growth factor-beta (TGFbeta) in a promoter-independent manner. In an activity-guided approach using reporter gene assays where the distal part of the 5-LO gene was included in the reporter gene plasmid, we localized vitamin D response elements (VDREs) within exon 10, exon 12, and intron M. We found that these newly identified VDRE sites are bound by vitamin D receptor both in vitro by gel-shift analysis and in vivo by chromatin immunoprecipitation assays. In reporter gene assays, the distal part of the 5-LO gene has promoter-like activity that is inducible by calcitriol in a vitamin D receptor-dependent manner. The vitamin D effects were attenuated when the VDREs in exon 10, exon 12, and intron M were deleted or mutated. When we analyzed the effects of calcitriol plus TGFbeta on chromatin modifications at exon 10, exon 12, and intron M of the 5-LO gene in Mono Mac 6 cells by chromatin immunoprecipitation analysis, we found an increase in histone H4 K20 monomethylation and a prominent presence of histone H3 K36 trimethylation. Combined treatment with calcitriol and TGFbeta also increased histone H4 acetylation, a marker for open chromatin, and the elongation form of RNA polymerase II at these sites, whereas the transcription initiation marker histone H3 K4 trimethylation was almost undetectable. The data suggest that calcitriol induces chromatin opening and transcript elongation via VDREs located at the 3'-end of the 5-LO gene.
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Affiliation(s)
- Kirsten L Stoffers
- Institute of Pharmaceutical Chemistry/ZAFES, University of Frankfurt, Max-von-Laue-Str. 9, D-60438 Frankfurt, Germany
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35
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Imbesi M, Dzitoyeva S, Ng LW, Manev H. 5-Lipoxygenase and epigenetic DNA methylation in aging cultures of cerebellar granule cells. Neuroscience 2009; 164:1531-7. [PMID: 19778587 DOI: 10.1016/j.neuroscience.2009.09.039] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2009] [Revised: 09/15/2009] [Accepted: 09/15/2009] [Indexed: 11/16/2022]
Abstract
5-Lipoxygenase (5-Lox), an enzyme involved in the metabolism of arachidonic acid participates in the modulation of the proliferation and differentiation of neural stem cells and cerebellar granule cell (CGC) precursors. Since epigenetic mechanisms including DNA methylation regulate 5-LOX expression and have been suggested as possible modulators of stem cell differentiation and aging, using primary cultures of mouse CGC (1, 5, 10, 14, 30 days in vitro; DIV), we studied DNA methylation patterns of the 5-LOX promoter and 5-LOX mRNA levels. We also measured the mRNA and protein content of the DNA methyltransferases DNMT1 and DNMT3a. 5-LOX, DNMT1, and DNMT3a mRNA levels were measured by real-time PCR. We observed that 5-LOX expression and the expression of maintenance DNMT1 is maximal at 1 DIV (proliferating neuronal precursors), whereas the expression of the de novo DNA methyltransferase DNMT3a mRNA increased in aging cultures. We analyzed the methylation status of the 5-LOX promoter using the methylation-sensitive restriction endonucleases AciI, BstUI, HpaII, and HinP1I, which digest unmethylated CpGs while leaving methylated CpGs intact. The 5-LOX DNA methylation increased with the age of the cells. Taken together, our data show that as cultured CGC mature and age in vitro, a decrease in 5-LOX mRNA content is accompanied by an increase in the methylation of the gene DNA. In addition, an increase in DNMT3a but not DNMT1 expression accompanies an increase of 5-LOX methylation during in vitro maturation.
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Affiliation(s)
- M Imbesi
- Department of Psychiatry, The Psychiatric Institute,University of Illinois at Chicago, Chicago, IL 60612, USA
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36
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Vikman S, Brena RM, Armstrong P, Hartiala J, Stephensen CB, Allayee H. Functional analysis of 5-lipoxygenase promoter repeat variants. Hum Mol Genet 2009; 18:4521-9. [PMID: 19717473 DOI: 10.1093/hmg/ddp414] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Variants of a hexanucleotide repeat polymorphism in the promoter of the 5-lipoxygenase (5-LO) gene have been associated with cardiovascular disease traits in humans, which may be due, at least in part, to differential expression of the at-risk alleles. To more fully characterize these variants, we carried out gene expression and DNA methylation studies in primary leukocytes from healthy individuals carrying various 5-LO promoter alleles. Regardless of genotype, 5-LO and 5-LO-activating protein (FLAP) gene expression was higher in granulocytes compared with monocytes and lymphocytes, whereas leukotriene A4 hydrolase (LTA4H) expression was higher in monocytes. In all three leukocyte populations, 5-LO mRNA levels were positively correlated with those of FLAP and LTA4H, with the highest correlation observed in granulocytes. In lymphocytes, individuals homozygous for the shorter 3 and 4 repeat alleles had between 20-35% higher 5-LO, FLAP and LTA4H expression compared with homozygous carriers of the wild-type 5 repeat allele (P = 0.03-0.0001). DNA methylation analysis of four CpG islands in a 1500 bp region encompassing the 5-LO promoter and the first approximately 100 bp of intron 1 revealed relatively low overall DNA methylation across all genotypes and leukocyte populations. However, analysis of the promoter repeats themselves demonstrated that, regardless of cell population, the 4 allele was methylated approximately twice as much as the 3 allele (P < 0.0001). Our results demonstrate that, in lymphocytes, the shorter repeat alleles of the 5-LO promoter lead to higher gene expression, which may be regulated through differential DNA methylation of the CpGs located within these repeats.
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Affiliation(s)
- Susanna Vikman
- Department of Preventive Medicine, USC Keck School of Medicine, Los Angeles, CA 90033, USA
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37
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Pogribny IP, Beland FA. DNA hypomethylation in the origin and pathogenesis of human diseases. Cell Mol Life Sci 2009; 66:2249-61. [PMID: 19326048 PMCID: PMC11115809 DOI: 10.1007/s00018-009-0015-5] [Citation(s) in RCA: 167] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2009] [Revised: 02/25/2009] [Accepted: 03/06/2009] [Indexed: 12/15/2022]
Abstract
The pathogenesis of any given human disease is a complex multifactorial process characterized by many biologically significant and interdependent alterations. One of these changes, specific to a wide range of human pathologies, is DNA hypomethylation. DNA hypomethylation signifies one of the major DNA methylation states that refers to a relative decrease from the "normal" methylation level. It is clear that disease by itself can induce hypomethylation of DNA; however, a decrease in DNA methylation can also have an impact on the predisposition to pathological states and disease development. This review presents evidence suggesting the involvement of DNA hypomethylation in the pathogenesis of several major human pathologies, including cancer, atherosclerosis, Alzheimer's disease, and psychiatric disorders.
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Affiliation(s)
- Igor P Pogribny
- Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, AR 72079, USA.
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38
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Transcellular biosynthesis of cysteinyl leukotrienes in vivo during mouse peritoneal inflammation. Proc Natl Acad Sci U S A 2009; 106:8296-301. [PMID: 19416808 DOI: 10.1073/pnas.0903851106] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Leukotrienes (LTs) are lipid mediators of inflammation formed by enzymatic oxidation of arachidonic acid. One intriguing aspect of LT production is transcellular biosynthesis: cells expressing 5-lipoxygenase (5LO) form LTA(4) and transfer it to cells expressing LTA(4) hydrolase (LTA(4)H) or LTC(4) synthase (LTC(4)S) to produce LTB(4) or LTC(4). This process has been demonstrated in vivo for LTB(4), but not for cysteinyl LTs (cysLTs). We examined transcellular cysLT synthesis during zymosan-induced peritonitis, using bone marrow transplants with transgenic mice deficient in key enzymes of LT synthesis and analyzing all eicosanoids by liquid chromatography/tandem mass spectrometry. WT mice time-dependently produced LTB(4) and cysLTs (LTC(4), LTD(4), and LTE(4)). 5LO(-/-) mice were incapable of producing LTs. WT bone marrow cells restored this biosynthetic ability, but 5LO(-/-) bone marrow did not rescue LT synthesis in irradiated WT mice, demonstrating that bone marrow-derived cells are the ultimate source of all LTs in this model. Total levels of 5LO-derived products were comparable in LTA(4)H(-/-) and WT mice, but were reduced in LTC(4)S(-/-) animals. No differences in prostaglandin production were observed between these transgenic or chimeric mice. Bone marrow cells from LTA(4)H(-/-) or LTC(4)S(-/-) mice injected into 5LO(-/-) mice restored the ability to synthesize LTB(4) and cysLTs, providing unequivocal evidence of efficient transcellular biosynthesis of cysLTs. These results highlight the potential relevance of transcellular exchange of LTA(4) for the synthesis of LTs mediating biological activities during inflammatory events in vivo.
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39
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Wang J, John EM, Ingles SA. 5-lipoxygenase and 5-lipoxygenase-activating protein gene polymorphisms, dietary linoleic acid, and risk for breast cancer. Cancer Epidemiol Biomarkers Prev 2008; 17:2748-54. [PMID: 18843019 DOI: 10.1158/1055-9965.epi-08-0439] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The n-6 polyunsaturated fatty acid 5-lipoxygenase pathway has been shown to play a role in the carcinogenesis of breast cancer. We conducted a population-based case-control study among Latina, African-American, and White women from the San Francisco Bay area to examine the association of the 5-lipoxygenase gene (ALOX5) and 5-lipoxygenase-activating protein gene (ALOX5AP) with breast cancer risk. Three ALOX5AP polymorphisms [poly(A) microsatellite, -4900 A>G (rs4076128), and -3472 A>G (rs4073259)] and three ALOX5 polymorphisms [Sp1-binding site (-GGGCGG-) variable number of tandem repeat polymorphism, -1279 G>T (rs6593482), and 760 G>A (rs2228065)] were genotyped in 802 cases and 888 controls. We did not find significant main effects of ALOX5 and ALOX5AP genotypes on breast cancer risk that were consistent across race or ethnicity; however, there was a significant interaction between the ALOX5AP -4900 A>G polymorphism and dietary linoleic acid intake (P=0.03). Among women consuming a diet high in linoleic acid (top quartile of intake, >17.4 g/d), carrying the AA genotype was associated with higher breast cancer risk (age- and race-adjusted odds ratio, 1.8; 95% confidence interval, 1.2-2.9) compared with carrying genotypes AG or GG. Among women consuming <or=17.4 g/d of linoleic acid, ALOX5AP -4900 genotype was not associated with breast cancer risk (age- and race-adjusted odds ratio, 0.9; 95% confidence interval, 0.7-1.2). These results support a role for n-6 polyunsaturated fatty acids in breast carcinogenesis and suggest that epidemiologic studies on dietary fat and breast cancer should take into account genetic predisposition related to n-6 polyunsaturated fatty acid metabolism.
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Affiliation(s)
- Jun Wang
- Tufts Medical Center, Tufts University School of Medicine, Boston, Massachusetts 02111, USA.
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40
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Abstract
5-lipoxygenase (5-LO) catalyzes two steps in biosynthesis of leukotrienes (LTs), a group of lipid mediators of inflammation derived from arachidonic acid (AA). LT antagonists are used in treatment of asthma; more recently a potential role also in atherosclerosis has raised considerable interest. Furthermore, possible effects of 5-LO metabolites in relation to tumorigenesis have emerged. Thus, an understanding of the biochemistry of this lipoxygenase has potential implications for treatment of various diseases.
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Affiliation(s)
- Olof Rådmark
- Department Medical Biochemistry and Biophysics, Division of Physiological Chemistry II, Karolinska Institutet, S-17177 Stockholm, Sweden
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Zhang Z, Li D, Wu M, Xiang B, Wang L, Zhou M, Chen P, Li X, Shen S, Li G. Promoter hypermethylation-mediated inactivation of LRRC4 in gliomas. BMC Mol Biol 2008; 9:99. [PMID: 18976507 PMCID: PMC2588634 DOI: 10.1186/1471-2199-9-99] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2008] [Accepted: 11/03/2008] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Leucine-rich repeat C4 protein (LRRC4) is a new member of the leucine-rich repeat (LRR) superfamily. It is not only a brain-specific gene but also a novel candidate for tumor suppression. LRRC4 inactivation is commonly found in glioma cell lines and primary glioma biopsies. However, little is known about the mechanism controlling LRRC4 expression. In a previous study, we did not find any genetic alteration in LRRC4 in primary glioma, which led us to explore an alternative mechanism underlying this phenomenon. METHODS In the present paper, we cloned the LRRC4 promoter with characteristics of a CpG island by luciferase reporter assay. Then, the CpG methylation status around the LRRC4 promoter region in glioma cell lines and primary gliomas was examined by methylation-specific PCR and bisulfite DNA sequencing. In order to demonstrate a functional association between LRRC4 promoter methylation and its gene inactivation, we performed DNA demethylation analysis with two human glioma cell lines using methylation-specific PCR and RT-PCR. RESULTS The sequence spanning positions -835 to -293 relative to the translation start site was identified as the LRRC4 promoter; this sequence is a TATA- and CAAT- less, high GC content region. It was found that LRRC4 promoter activity is strongly suppressed after treatment with SssI methylase in vitro. Furthermore, LRRC4 promoter methylation was observed by methylation-specific PCR in two glioma cell lines and all 30 primary glioma specimens, but not in normal brain tissue. Bisulfite DNA sequencing showed that most of the CpG sites were located around the LRRC4 promoter methylated in glioma cells and tissues, but not in normal brain tissue. In addition, the methylase inhibitor 5-Aza-2'-deoxycytidine could induce LRRC4 mRNA expression and LRRC4 promoter partial demethylation in SF126 and SF767 glioma cells. CONCLUSION Methylation-mediated inactivation of LRRC4 is a frequent and glioma-specific event, and it may be a potential biomarker for diagnosis or prognosis, or serve as a therapeutic target.
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Affiliation(s)
- Zuping Zhang
- Cancer Research Institute, Central South University, Changsha 410078, Hunan, PR China.
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Allayee H, Baylin A, Hartiala J, Wijesuriya H, Mehrabian M, Lusis AJ, Campos H. Nutrigenetic association of the 5-lipoxygenase gene with myocardial infarction. Am J Clin Nutr 2008; 88:934-40. [PMID: 18842779 PMCID: PMC3014055 DOI: 10.1093/ajcn/88.4.934] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND 5-Lipoxygenase (5-LO) catalyzes the rate-limiting step of the biosynthesis of proinflammatory leukotrienes from arachidonic acid (AA) and has been associated with atherosclerosis in animal models and humans. We previously reported that variants of a 5-LO promoter repeat polymorphism were associated with carotid atherosclerosis in humans, an effect that was exacerbated by high dietary AA but mitigated by high dietary n-3 fatty acids. OBJECTIVE We sought to confirm these initial observations with a more clinically relevant phenotype such as myocardial infarction (MI). DESIGN The 5-LO polymorphism was genotyped in 1885 Costa Rican case-control pairs and tested for association with MI. Functional experiments were carried out to determine whether the associated alleles had differences in mRNA expression. RESULTS The frequency of variant genotype groups did not differ significantly between cases and controls. However, a significant gene x diet interaction was observed, in which, relative to the common 5 repeat allele, the 3 and 4 alleles were associated with a higher MI risk in the high (> or = 0.25 g/d) dietary AA group (odds ratio: 1.31; 95% CI: 1.07, 1.61) and with a lower risk in the low (<0. 25 g/d) AA group (0.77; 0.63, 0.94) (P for interaction = 0.015). Using allele-specific quantitation, the short alleles had expression approximately twice that of the 5 allele (P < 0.0001). CONCLUSIONS The 3 and 4 variants lead to higher 5-LO expression and provide additional evidence that these alleles are associated with greater risks of atherosclerosis and MI in the context of a high-AA diet.
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Affiliation(s)
- Hooman Allayee
- Department of Preventive Medicine and the Institute for Genetic Medicine, the University of Southern California Keck School of Medicine, Los Angeles, CA 90089-9075, USA.
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Schnur N, Seuter S, Katryniok C, Rådmark O, Steinhilber D. The histone deacetylase inhibitor trichostatin A mediates upregulation of 5-lipoxygenase promoter activity by recruitment of Sp1 to distinct GC-boxes. Biochim Biophys Acta Mol Cell Biol Lipids 2007; 1771:1271-82. [PMID: 17894944 DOI: 10.1016/j.bbalip.2007.08.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2007] [Revised: 07/20/2007] [Accepted: 08/06/2007] [Indexed: 11/28/2022]
Abstract
The histone deacetylase inhibitor trichostatin A (TsA) potently induces 5-lipoxygenase (5-LO) promoter activity in reporter gene assays as well as 5-LO mRNA expression. We identified two proximal Sp1/Sp3 binding sites in the 5-LO gene promoter mediating the TsA effect in both 5-LO-negative HeLa cells and in 5-LO expressing Mono Mac 6 (MM6) cells, the tandem GC-boxes, by contrast, were not important for the TsA effect. TsA neither altered the protein expression levels of Sp1/Sp3 nor of the histone deacetylases HDAC1/2, nor did it apparently change the protein complex formation by these factors. Also, treatment of cells with TsA did not change the binding affinity of Sp1/Sp3 in cell extracts, as tested by DAPA analysis using probes containing the proximal GC boxes. However, in the living cell TsA induced Sp1, Sp3 and RNA polymerase II recruitment to the 5-LO promoter without changing the acetylation status of histone protein H4. Cotransfection studies suggest that both Sp1 and Sp3 can mediate the TsA effect. This is the first report demonstrating that Sp3 is involved in the regulation of 5-LO promoter activity. In summary, we show that TsA increases 5-LO promoter activity by the enhanced recruitment of Sp1 and Sp3 to the 5-LO promoter.
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Affiliation(s)
- Nicole Schnur
- Institute of Pharmaceutical Chemistry/ZAFES, University of Frankfurt, Max-von-Laue-Str. 9, D-60438 Frankfurt, Germany
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Abstract
Leukotrienes are metabolites of arachidonic acid derived from the action of 5-LO (5-lipoxygenase). The immediate product of 5-LO is LTA4 (leukotriene A4), which is enzymatically converted into either LTB4 (leukotriene B4) by LTA4 hydrolase or LTC4 (leukotriene C4) by LTC4 synthase. The regulation of leukotriene production occurs at various levels, including expression of 5-LO, translocation of 5-LO to the perinuclear region and phosphorylation to either enhance or inhibit the activity of 5-LO. Several other proteins, including cPLA2α (cytosolic phospholipase A2α) and FLAP (5-LO-activating protein) also assemble at the perinuclear region before production of LTA4. LTC4 synthase is an integral membrane protein that is present at the nuclear envelope; however, LTA4 hydrolase remains cytosolic. Biologically active LTB4 is metabolized by ω-oxidation carried out by specific cytochrome P450s (CYP4F) followed by β-oxidation from the ω-carboxy position and after CoA ester formation. Other specific pathways of leukotriene metabolism include the 12-hydroxydehydrogenase/15-oxo-prostaglandin-13-reductase that forms a series of conjugated diene metabolites that have been observed to be excreted into human urine. Metabolism of LTC4 occurs by sequential peptide cleavage reactions involving a γ-glutamyl transpeptidase that forms LTD4 (leukotriene D4) and a membrane-bound dipeptidase that converts LTD4 into LTE4 (leukotriene E4) before ω-oxidation. These metabolic transformations of the primary leukotrienes are critical for termination of their biological activity, and defects in expression of participating enzymes may be involved in specific genetic disease.
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Affiliation(s)
- Robert C Murphy
- Department of Pharmacology, Mail Stop 8303, University of Colorado at Denver and Health Sciences Center, 12801 E. 17th Avenue, P.O. Box 6511, Aurora, CO 80045-0511, USA
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Cheli Y, Kanaji S, Jacquelin B, Chang M, Nugent DJ, Kunicki TJ. Transcriptional and epigenetic regulation of the integrin collagen receptor locus ITGA1-PELO-ITGA2. ACTA ACUST UNITED AC 2007; 1769:546-58. [PMID: 17669516 PMCID: PMC2682338 DOI: 10.1016/j.bbaexp.2007.06.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2007] [Revised: 06/11/2007] [Accepted: 06/25/2007] [Indexed: 12/26/2022]
Abstract
The integrin collagen receptor locus on human chromosome 5q11.2 includes the integrin genes ITGA1 and ITGA2, and the cell cycle regulation gene PELO, embedded within ITGA1 intron 1. ITGA1 contains a CArG box that is bound by serum response factor (SRF), while PELO contains two Sp1 binding elements. A comparison of mRNA levels in megakaryocytic (MK) and non-megakaryocytic (non-MK) cell lines and an analysis of the transcriptional activity of promoter-LUC reporter gene constructs in transfected cells revealed that ITGA1 is selectively suppressed in the MK lineage. Sodium bisulfite genomic sequencing established that a CpG-rich ITGA1 promoter region (-209/+115) is fully methylated at 19 CpG sites in MK cells that do not express alpha1beta1, but completely demethylated in expressing cells. In vitro methylation of ITGA1 suppresses transcription, while treatment of megakaryocytic cells with 5-aza-2'-deoxycytidine, but not Trichostatin A, resulted in de novo expression of ITGA1. During thrombopoietin-induced in vitro differentiation of primary human cord blood mononuclear cells into megakaryocytes, we observed rapid, progressive CpG methylation of ITGA1, but not PELO or ITGA2. Thus, selective CpG methylation of the ITGA1 promoter is a specific feature of alpha1beta1 regulation that coincides with the initiation of megakaryocyte differentiation.
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MESH Headings
- Azacitidine/analogs & derivatives
- Azacitidine/pharmacology
- Cell Differentiation/drug effects
- Cell Differentiation/physiology
- Chromosomes, Human, Pair 5/genetics
- Chromosomes, Human, Pair 5/metabolism
- DNA Methylation/drug effects
- Decitabine
- Enzyme Inhibitors/pharmacology
- Epigenesis, Genetic/drug effects
- Epigenesis, Genetic/physiology
- HeLa Cells
- Humans
- Hydroxamic Acids/pharmacology
- Integrin alpha1/biosynthesis
- Integrin alpha1/genetics
- Integrin alpha1beta1/biosynthesis
- Integrin alpha1beta1/genetics
- Integrin alpha2/biosynthesis
- Integrin alpha2/genetics
- Introns/physiology
- K562 Cells
- Leukocytes, Mononuclear/cytology
- Leukocytes, Mononuclear/metabolism
- Megakaryocytes/cytology
- Megakaryocytes/metabolism
- Nuclear Proteins/biosynthesis
- Nuclear Proteins/genetics
- Promoter Regions, Genetic/physiology
- Quantitative Trait Loci/physiology
- Thrombopoietin/pharmacology
- Transcription, Genetic
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Affiliation(s)
- Yann Cheli
- The Roon Research Center for Arteriosclerosis and Thrombosis, The Scripps Research Institute, La Jolla, CA 92037
| | - Sachiko Kanaji
- The Roon Research Center for Arteriosclerosis and Thrombosis, The Scripps Research Institute, La Jolla, CA 92037
- Division of Experimental Hemostasis and Thrombosis, The Scripps Research Institute, La Jolla, CA 92037
| | - Beatrice Jacquelin
- The Roon Research Center for Arteriosclerosis and Thrombosis, The Scripps Research Institute, La Jolla, CA 92037
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA 92037
| | - Mei Chang
- Children’s Hospital of Orange County, Orange, CA 92868
| | | | - Thomas J. Kunicki
- The Roon Research Center for Arteriosclerosis and Thrombosis, The Scripps Research Institute, La Jolla, CA 92037
- Address correspondence to: Thomas J. Kunicki Ph.D., Department of Molecular and Experimental Medicine, Maildrop MEM150, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, Tel. 858-784-2668, Fax 858-784-2174,
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Rådmark O, Werz O, Steinhilber D, Samuelsson B. 5-Lipoxygenase: regulation of expression and enzyme activity. Trends Biochem Sci 2007; 32:332-41. [PMID: 17576065 DOI: 10.1016/j.tibs.2007.06.002] [Citation(s) in RCA: 342] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2007] [Revised: 05/01/2007] [Accepted: 06/04/2007] [Indexed: 11/16/2022]
Abstract
5-Lipoxygenase (5-LO) catalyzes the first two steps in the biosynthesis of leukotrienes, a group of pro-inflammatory lipid mediators derived from arachidonic acid. Leukotriene antagonists are used in the treatment of asthma, and the potential role of leukotrienes in atherosclerosis, another chronic inflammatory disease, has recently received considerable attention. In addition, some possible effects of 5-LO metabolites in tumorigenesis have emerged. Thus, knowledge of the biochemistry of this enzyme has potential implications for the treatment of various diseases. Recent advances have expanded our understanding of the regulatory mechanisms underlying the expression and control of 5-LO activity. With regard to the control of enzyme activity, many of these findings focus on the N-terminal domain of 5-LO.
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Affiliation(s)
- Olof Rådmark
- Department of Medical Biochemistry and Biophysics, Division of Physiological Chemistry II, Karolinska Institutet, S-17177 Stockholm, Sweden.
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González P, Reguero JR, Lozano I, Morís C, Coto E. A functional Sp1/Egr1-tandem repeat polymorphism in the 5-lipoxygenase gene is not associated with myocardial infarction. Int J Immunogenet 2007; 34:127-30. [PMID: 17373938 DOI: 10.1111/j.1744-313x.2007.00671.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Arachidonate 5-lipoxygenase is an enzyme encoded by the ALOX5 gene, and plays an important role in the synthesis of leukotrienes. These are inflammatory mediators, and have been involved in atherosclerosis and other pathological processes that require proinflammatory activities. Human and animal studies have suggested a role for the ALOX5 gene in atherosclerosis, including a significant association between a promoter polymorphism and a carotid intimal-medial thickness in response to dietary fat. This polymorphism was three- to six-tandem repeats of a Sp1/Egr1 binding motif (GGGCGG)(n), and the number of repeats has been linked with the amount of gene expression. We hypothesized that this ALOX5 polymorphism could influence the risk for myocardial infarction (MI). First, we analysed the effect of the four alleles on gene expression by transfecting the HEK-293 cell line with luciferase reporter-constructs. We found that luciferase activities are dependent on the number of the Sp1/Egr1 repeats, with the three and six repeats having the lowest and highest values. We genotyped 312 male MI survivors, aged < 55 years, and 376 healthy controls matched with patients for sex, age, and ethnicity. Ninety-six per cent of the patients were smokers, compared to only 42% among the controls (P < 0.001; OR = 31.84). The 55 + 56 repeat genotypes were less frequent in patients (55 = 56%, 56 = 0.6%) compared to controls (55 = 60%, 56 = 3%). However, these were non-significantly different frequencies. In addition, no difference in MI-onset age and biochemical values was found between the allele and genotypes. In conclusion, we confirmed the effect of the ALOX5-promoter polymorphism on gene expression, but our data did not support a significant effect of this functional variation on MI risk.
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Affiliation(s)
- P González
- Genética Molecular-Instituto de Estudios Nefrológicos, Hospital Central de Asturias, Oviedo, Spain
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48
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Cook-Moreau JM, El-Makhour Hojeij Y, Barrière G, Rabinovitch-Chable HC, Faucher KS, Sturtz FG, Rigaud MA. Expression of 5-lipoxygenase (5-LOX) in T lymphocytes. Immunology 2007; 122:157-66. [PMID: 17484769 PMCID: PMC2265994 DOI: 10.1111/j.1365-2567.2007.02621.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
5-Lipoxygenase (5-LOX) is the key enzyme responsible for the synthesis of the biologically active leukotrienes. Its presence has been reported in cells of the myeloid lineage and B lymphocytes but has not been formally defined in T lymphocytes. In this study, we provide evidence for 5-LOX expression on both transcriptional and translational levels in highly purified peripheral blood T cells as well as in human T lymphoblastoid cell lines (MOLT4 and Jurkat). Messenger RNA (mRNA) of 5-LOX was amplified by conventional reverse transcription-polymerase chain reaction (RT-PCR; MOLT4 and Jurkat cells) and by in situ RT-PCR (T lymphocytes). 5-LOX protein expression was confirmed by Western blot and immunofluorescence studies. 5-LOX was present primarily in the cytoplasm with some nuclear localization and was translocated to the nuclear periphery after culture in a mitosis-supporting medium. Fluorescence-activated cell sorter analysis of different T-lymphocyte populations, including CD4, CD8, CD45RO, CD45RA, T helper type 2, and T-cell receptor-alphabeta and -gammadelta expressing cells, did not identify a differential distribution of the enzyme. Purified peripheral blood T lymphocytes were incapable of synthesizing leukotrienes in the absence of exogenous arachidonic acid. Jurkat cells produced leukotriene C(4) and a small amount of leukotriene B(4) in response to CD3-CD28 cross-linking. This synthesis was abolished by two inhibitors of leukotriene synthesis, MK-886 and AA-861. The presence of 5-LOX in T lymphocytes but the absence of endogenous lipoxygenase metabolite production compared to Jurkat cells may constitute a fundamental difference between resting peripheral lymphocytes and leukaemic cells.
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Affiliation(s)
- Jeanne M Cook-Moreau
- Laboratoire de Biochimie et Génétique Moléculaire, Faculté de Médecine, Limoges, France.
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Seuter S, Väisänen S, Rådmark O, Carlberg C, Steinhilber D. Functional characterization of vitamin D responding regions in the human 5-Lipoxygenase gene. Biochim Biophys Acta Mol Cell Biol Lipids 2007; 1771:864-72. [PMID: 17500032 DOI: 10.1016/j.bbalip.2007.04.007] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2006] [Revised: 03/30/2007] [Accepted: 04/06/2007] [Indexed: 12/27/2022]
Abstract
5-lipoxygenase (5-LO) is the key enzyme in the biosynthesis of proinflammatory leukotrienes. The 5-LO gene is a primary target of 1alpha,25-dihydroxyvitamin D(3) (1alpha,25(OH)(2)D(3)) and its expression is prominently increased during myeloid cell differentiation. Since no functional vitamin D response element (VDRE) has been reported for this gene so far, we performed in silico screening of the whole 5-LO gene area (84 kb, including 10 kb promoter region) and identified 22 putative VDREs. Both gelshift and reporter gene assays identified four of these candidates as functional VDREs. Their approximate positions are -2,250 (promoter), +21,400 (intron 2), +42,000 (intron 4) and +50,600 (intron 5) in relation to the transcription start site (TSS). Remarkably, the VDRE at position +42,000 is one of the strongest known VDREs of the human genome. Chromatin immunoprecipitation (ChIP) assays demonstrated simultaneous association of vitamin D receptor (VDR), retinoid X receptor (RXR) and RNA polymerase II (Pol II) to the 5-LO gene regions containing two of these four putative VDREs. This indicates DNA looping of the TSS to even very distant gene regions. In summary, we suggest that the upregulation of the primary 1alpha,25(OH)(2)D(3) target 5-LO is mediated in vivo by a prominent VDRE in intron 4.
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Affiliation(s)
- Sabine Seuter
- Institute of Pharmaceutical Chemistry, University of Frankfurt, D-60438 Frankfurt, Germany.
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50
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Scharf S, Zech J, Bursen A, Schraets D, Oliver PL, Kliem S, Pfitzner E, Gillert E, Dingermann T, Marschalek R. Transcription linked to recombination: a gene-internal promoter coincides with the recombination hot spot II of the human MLL gene. Oncogene 2006; 26:1361-71. [PMID: 16983345 DOI: 10.1038/sj.onc.1209948] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The MLL gene is frequently involved in chromosomal translocations associated with high-risk acute leukaemia. Infant and therapy-related acute leukaemia patients display chromosomal breakpoints preferentially clustered in the telomeric portion of the MLL breakpoint cluster region (SCII). Here, we demonstrate that SCII colocalizes with a gene-internal promoter element in the mouse and human MLL gene, respectively. The mRNA generated encodes an N-terminally truncated version of MLL that still exhibits many functional regions, including the C-terminal SET-domain. Etoposide-induced DNA double-strand breaks colocalize with the binding site of RNA polymerase II and the transcription initiation region, but not with a nearby Topo II consensus sequence. Thus, the observed genomic instability of the human MLL gene is presumably linked to transcriptional processes. The consequences of this novel finding for the creation of chromosomal translocations, the biology of the MLL protein and for MLL-mediated acute leukaemia are discussed.
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Affiliation(s)
- S Scharf
- Institute of Pharmaceutical Biology/ZAFES, Biocenter, JWG-University of Frankfurt, Frankfurt/Main, Germany
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