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He S, Moutaoufik MT, Islam S, Persad A, Wu A, Aly KA, Fonge H, Babu M, Cayabyab FS. HERG channel and cancer: A mechanistic review of carcinogenic processes and therapeutic potential. Biochim Biophys Acta Rev Cancer 2020; 1873:188355. [PMID: 32135169 DOI: 10.1016/j.bbcan.2020.188355] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 02/28/2020] [Accepted: 02/28/2020] [Indexed: 12/21/2022]
Abstract
The human ether-à-go-go related gene (HERG) encodes the alpha subunit of Kv11.1, which is a voltage-gated K+ channel protein mainly expressed in heart and brain tissue. HERG plays critical role in cardiac repolarization, and mutations in HERG can cause long QT syndrome. More recently, evidence has emerged that HERG channels are aberrantly expressed in many kinds of cancer cells and play important roles in cancer progression. HERG could therefore be a potential biomarker for cancer and a possible molecular target for anticancer drug design. HERG affects a number of cellular processes, including cell proliferation, apoptosis, angiogenesis and migration, any of which could be affected by dysregulation of HERG. This review provides an overview of available information on HERG channel as it relates to cancer, with focus on the mechanism by which HERG influences cancer progression. Molecular docking attempts suggest two possible protein-protein interactions of HERG with the ß1-integrin receptor and the transcription factor STAT-1 as novel HERG-directed therapeutic targeting which avoids possible cardiotoxicity. The role of epigenetics in regulating HERG channel expression and activity in cancer will also be discussed. Finally, given its inherent extracellular accessibility as an ion channel, we discuss regulatory roles of this molecule in cancer physiology and therapeutic potential. Future research should be directed to explore the possibilities of therapeutic interventions targeting HERG channels while minding possible complications.
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Affiliation(s)
- Siyi He
- Department of Surgery, Neuroscience Research Group, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | | | - Saadul Islam
- Department of Surgery, Neuroscience Research Group, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Amit Persad
- Department of Surgery, Neuroscience Research Group, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Adam Wu
- Department of Surgery, Neuroscience Research Group, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Khaled A Aly
- Department of Biochemistry, University of Regina, Regina, SK S4S 0A2, Canada
| | - Humphrey Fonge
- Department of Medical Imaging, University of Saskatchewan, Saskatoon, Saskatchewan S7N 0W8, Canada; Department of Medical Imaging, Royal University Hospital, Saskatoon, Saskatchewan S7N 0W8, Canada
| | - Mohan Babu
- Department of Biochemistry, University of Regina, Regina, SK S4S 0A2, Canada
| | - Francisco S Cayabyab
- Department of Surgery, Neuroscience Research Group, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada.
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Thurber AE, Nelson M, Frost CL, Levin M, Brackenbury WJ, Kaplan DL. IK channel activation increases tumor growth and induces differential behavioral responses in two breast epithelial cell lines. Oncotarget 2017; 8:42382-42397. [PMID: 28415575 PMCID: PMC5522074 DOI: 10.18632/oncotarget.16389] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 03/08/2017] [Indexed: 12/26/2022] Open
Abstract
Many potassium channel families are over-expressed in cancer, but their mechanistic role in disease progression is poorly understood. Potassium channels modulate membrane potential (Vmem) and thereby influence calcium ion dynamics and other voltage-sensitive signaling mechanisms, potentially acting as transcriptional regulators. This study investigated the differential response to over-expression and activation of a cancer-associated potassium channel, the intermediate conductance calcium-activated potassium channel (IK), on aggressive behaviors in mammary epithelial and breast cancer cell lines. IK was over-expressed in the highly metastatic breast cancer cell line MDA-MB-231 and the spontaneously immortalized breast epithelial cell line MCF-10A, and the effect on cancer-associated behaviors was assessed. IK over-expression increased primary tumor growth and metastasis of MDA-MB-231 in orthotopic xenografts, demonstrating for the first time in any cancer type that increased IK is sufficient to promote cancer aggression. The primary tumors had similar vascularization as determined by CD31 staining and similar histological characteristics. Interestingly, despite the increased in vivo growth and metastasis, neither IK over-expression nor activation with agonist had a significant effect on MDA-MB-231 proliferation, invasion, or migration in vitro. In contrast, IK decreased MCF-10A proliferation and invasion through Matrigel but had no effect on migration in a scratch-wound assay. We conclude that IK activity is sufficient to promote cell aggression in vivo. Our data provide novel evidence supporting IK and downstream signaling networks as potential targets for cancer therapies.
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Affiliation(s)
- Amy E. Thurber
- Program in Cell, Molecular, and Developmental Biology, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, Massachusetts, USA
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts, USA
| | - Michaela Nelson
- Department of Biology, University of York, Heslington, York, UK
| | | | - Michael Levin
- Biology Department, and Tufts Center for Regenerative and Developmental Biology, Tufts University, Medford, Massachusetts, USA
| | | | - David L. Kaplan
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts, USA
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Tanner MR, Pennington MW, Laragione T, Gulko PS, Beeton C. KCa1.1 channels regulate β 1-integrin function and cell adhesion in rheumatoid arthritis fibroblast-like synoviocytes. FASEB J 2017; 31:3309-3320. [PMID: 28428266 DOI: 10.1096/fj.201601097r] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 04/05/2017] [Indexed: 01/01/2023]
Abstract
Large-conductance calcium-activated potassium channel (KCa1.1; BK, Slo1, MaxiK, KCNMA1) is the predominant potassium channel expressed at the plasma membrane of rheumatoid arthritis fibroblast-like synoviocytes (RA-FLSs) isolated from the synovium of patients with RA. It is a critical regulator of RA-FLS migration and invasion and therefore represents an attractive target for the therapy of RA. However, the molecular mechanisms by which KCa1.1 regulates RA-FLS invasiveness have remained largely unknown. Here, we demonstrate that KCa1.1 regulates RA-FLS adhesion through controlling the plasma membrane expression and activation of β1 integrins, but not α4, α5, or α6 integrins. Blocking KCa1.1 disturbs calcium homeostasis, leading to the sustained phosphorylation of Akt and the recruitment of talin to β1 integrins. Interestingly, the pore-forming α subunit of KCa1.1 coimmunoprecipitates with β1 integrins, suggesting that this physical association underlies the functional interaction between these molecules. Together, these data outline a new signaling mechanism by which KCa1.1 regulates β1-integrin function and therefore invasiveness of RA-FLSs.-Tanner, M. R., Pennington, M. W., Laragione, T., Gulko, P. S., Beeton, C. KCa1.1 channels regulate β1-integrin function and cell adhesion in rheumatoid arthritis fibroblast-like synoviocytes.
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Affiliation(s)
- Mark R Tanner
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, USA.,Graduate School of Biomedical Sciences, Baylor College of Medicine, Houston, Texas, USA
| | | | - Teresina Laragione
- Division of Rheumatology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Pércio S Gulko
- Division of Rheumatology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Christine Beeton
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, USA; .,Biology of Inflammation Center, Baylor College of Medicine, Houston, Texas, USA.,Center for Drug Discovery, Baylor College of Medicine, Houston, Texas, USA
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Fernández-Valle Á, Rodrigo JP, Rodríguez-Santamarta T, Villaronga MÁ, Álvarez-Teijeiro S, García-Pedrero JM, Suárez-Fernández L, Lequerica-Fernández P, de Vicente JC. HERG1 potassium channel expression in potentially malignant disorders of the oral mucosa and prognostic relevance in oral squamous cell carcinoma. Head Neck 2016; 38:1672-1678. [DOI: 10.1002/hed.24493] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 02/24/2016] [Accepted: 03/21/2016] [Indexed: 01/17/2023] Open
Affiliation(s)
- Álvaro Fernández-Valle
- Department of Oral and Maxillofacial Surgery; Hospital Universitario Central de Asturias (HUCA); Oviedo Asturias Spain
| | - Juan Pablo Rodrigo
- Department of Otolaryngology; Hospital Universitario Central de Asturias (HUCA); Oviedo Asturias Spain
- Instituto Universitario de Oncología del Principado de Asturias (IUOPA); Hospital Universitario Central de Asturias, Edificio Consultas Externas, Planta Baja Lab 2 ORL-IUOPA; Oviedo Asturias Spain
| | - Tania Rodríguez-Santamarta
- Department of Oral and Maxillofacial Surgery; Hospital Universitario Central de Asturias (HUCA); Oviedo Asturias Spain
| | - M. Ángeles Villaronga
- Instituto Universitario de Oncología del Principado de Asturias (IUOPA); Hospital Universitario Central de Asturias, Edificio Consultas Externas, Planta Baja Lab 2 ORL-IUOPA; Oviedo Asturias Spain
| | - Saúl Álvarez-Teijeiro
- Instituto Universitario de Oncología del Principado de Asturias (IUOPA); Hospital Universitario Central de Asturias, Edificio Consultas Externas, Planta Baja Lab 2 ORL-IUOPA; Oviedo Asturias Spain
| | - Juana M. García-Pedrero
- Instituto Universitario de Oncología del Principado de Asturias (IUOPA); Hospital Universitario Central de Asturias, Edificio Consultas Externas, Planta Baja Lab 2 ORL-IUOPA; Oviedo Asturias Spain
| | - Laura Suárez-Fernández
- Instituto Universitario de Oncología del Principado de Asturias (IUOPA); Hospital Universitario Central de Asturias, Edificio Consultas Externas, Planta Baja Lab 2 ORL-IUOPA; Oviedo Asturias Spain
| | | | - Juan Carlos de Vicente
- Department of Oral and Maxillofacial Surgery; Hospital Universitario Central de Asturias (HUCA); Oviedo Asturias Spain
- Instituto Universitario de Oncología del Principado de Asturias (IUOPA); Hospital Universitario Central de Asturias, Edificio Consultas Externas, Planta Baja Lab 2 ORL-IUOPA; Oviedo Asturias Spain
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Voltage-Gated K+ Channel, Kv3.3 Is Involved in Hemin-Induced K562 Differentiation. PLoS One 2016; 11:e0148633. [PMID: 26849432 PMCID: PMC4743930 DOI: 10.1371/journal.pone.0148633] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 01/20/2016] [Indexed: 12/31/2022] Open
Abstract
Voltage-gated K+ (Kv) channels are well known to be involved in cell proliferation. However, even though cell proliferation is closely related to cell differentiation, the relationship between Kv channels and cell differentiation remains poorly investigated. This study demonstrates that Kv3.3 is involved in K562 cell erythroid differentiation. Down-regulation of Kv3.3 using siRNA-Kv3.3 increased hemin-induced K562 erythroid differentiation through decreased activation of signal molecules such as p38, cAMP response element-binding protein, and c-fos. Down-regulation of Kv3.3 also enhanced cell adhesion by increasing integrin β3 and this effect was amplified when the cells were cultured with fibronectin. The Kv channels, or at least Kv3.3, appear to be associated with cell differentiation; therefore, understanding the mechanisms of Kv channel regulation of cell differentiation would provide important information regarding vital cellular processes.
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Kv10.1 K+ channel: from physiology to cancer. Pflugers Arch 2016; 468:751-62. [DOI: 10.1007/s00424-015-1784-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 12/11/2015] [Accepted: 12/27/2015] [Indexed: 12/18/2022]
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Involvement of potassium channels in the progression of cancer to a more malignant phenotype. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1848:2477-92. [PMID: 25517985 DOI: 10.1016/j.bbamem.2014.12.008] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 12/01/2014] [Accepted: 12/08/2014] [Indexed: 12/22/2022]
Abstract
Potassium channels are a diverse group of pore-forming transmembrane proteins that selectively facilitate potassium flow through an electrochemical gradient. They participate in the control of the membrane potential and cell excitability in addition to different cell functions such as cell volume regulation, proliferation, cell migration, angiogenesis as well as apoptosis. Because these physiological processes are essential for the correct cell function, K+ channels have been associated with a growing number of diseases including cancer. In fact, different K+ channel families such as the voltage-gated K+ channels, the ether à-go-go K+ channels, the two pore domain K+ channels and the Ca2+-activated K+ channels have been associated to tumor biology. Potassium channels have a role in neoplastic cell-cycle progression and their expression has been found abnormal in many types of tumors and cancer cells. In addition, the expression and activity of specific K+ channels have shown a significant correlation with the tumor malignancy grade. The aim of this overview is to summarize published data on K+ channels that exhibit oncogenic properties and have been linked to a more malignant cancer phenotype. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers.
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Pier DM, Shehatou GSG, Giblett S, Pullar CE, Trezise DJ, Pritchard CA, Challiss RAJ, Mitcheson JS. Long-term channel block is required to inhibit cellular transformation by human ether-à-go-go-related gene (hERG1) potassium channels. Mol Pharmacol 2014; 86:211-21. [PMID: 24830940 DOI: 10.1124/mol.113.091439] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Both human ether-à-go-go-related gene (hERG1) and the closely related human ether-à-go-go (hEAG1) channel are aberrantly expressed in a large proportion of human cancers. In the present study, we demonstrate that transfection of hERG1 into mouse fibroblasts is sufficient to induce many features characteristic of malignant transformation. An important finding of this work is that this transformation could be reversed by chronic incubation (for 2-3 weeks) with the hERG channel blocker dofetilide (100 nM), whereas more acute applications (for 1-2 days) were ineffective. The hERG1 expression resulted in a profound loss of cell contact inhibition, multiple layers of overgrowing cells, and high saturation densities. Cells also changed from fibroblast-like to a more spindle-shaped morphology, which was associated with a smaller cell size, a dramatic increase in cell polarization, a reduction in the number of actin stress fibers, and less punctate labeling of focal adhesions. Analysis of single-cell migration and scratch-wound closure clearly demonstrated that hERG1-expressing cells migrated more rapidly than vector-transfected control cells. In contrast to previous studies on hEAG1, there were no increases in rates of proliferation, or loss of growth factor dependency; however, hERG1-expressing cells were capable of substrate-independent growth. Allogeneic transplantation of hERG1-expressing cells into nude mice resulted in an increased incidence of tumors. In contrast to hEAG1, the mechanism of cellular transformation is dependent on ion conduction. Trafficking-deficient and conduction-deficient hERG1 mutants also prevented cellular transformation. These results provide evidence that hERG1 expression is sufficient to induce cellular transformation by a mechanism distinct from hEAG1. The most important conclusion of this study is that selective hERG1 channel blockers have therapeutic potential in the treatment of hERG1-expressing cancers.
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Affiliation(s)
- David M Pier
- Department of Cell Physiology and Pharmacology (D.M.P., G.S.G.S., C.E.P., R.A.J.C., J.S.M.) and Department of Biochemistry (S.G., C.A.P.), University of Leicester, Leicester, United Kingdom; Molecular Discovery Research, GlaxoSmithKline R&D, Harlow, Essex, United Kingdom (D.J.T.); Department of Pharmacology and Toxicology, University of Mansoura, Egypt (G.S.G.S.); Essen Bioscience Ltd., Welwyn Garden City, UK (D.J.T.); School of Clinical Sciences, University of Edinburgh, United Kingdom (D.M.P.)
| | - George S G Shehatou
- Department of Cell Physiology and Pharmacology (D.M.P., G.S.G.S., C.E.P., R.A.J.C., J.S.M.) and Department of Biochemistry (S.G., C.A.P.), University of Leicester, Leicester, United Kingdom; Molecular Discovery Research, GlaxoSmithKline R&D, Harlow, Essex, United Kingdom (D.J.T.); Department of Pharmacology and Toxicology, University of Mansoura, Egypt (G.S.G.S.); Essen Bioscience Ltd., Welwyn Garden City, UK (D.J.T.); School of Clinical Sciences, University of Edinburgh, United Kingdom (D.M.P.)
| | - Susan Giblett
- Department of Cell Physiology and Pharmacology (D.M.P., G.S.G.S., C.E.P., R.A.J.C., J.S.M.) and Department of Biochemistry (S.G., C.A.P.), University of Leicester, Leicester, United Kingdom; Molecular Discovery Research, GlaxoSmithKline R&D, Harlow, Essex, United Kingdom (D.J.T.); Department of Pharmacology and Toxicology, University of Mansoura, Egypt (G.S.G.S.); Essen Bioscience Ltd., Welwyn Garden City, UK (D.J.T.); School of Clinical Sciences, University of Edinburgh, United Kingdom (D.M.P.)
| | - Christine E Pullar
- Department of Cell Physiology and Pharmacology (D.M.P., G.S.G.S., C.E.P., R.A.J.C., J.S.M.) and Department of Biochemistry (S.G., C.A.P.), University of Leicester, Leicester, United Kingdom; Molecular Discovery Research, GlaxoSmithKline R&D, Harlow, Essex, United Kingdom (D.J.T.); Department of Pharmacology and Toxicology, University of Mansoura, Egypt (G.S.G.S.); Essen Bioscience Ltd., Welwyn Garden City, UK (D.J.T.); School of Clinical Sciences, University of Edinburgh, United Kingdom (D.M.P.)
| | - Derek J Trezise
- Department of Cell Physiology and Pharmacology (D.M.P., G.S.G.S., C.E.P., R.A.J.C., J.S.M.) and Department of Biochemistry (S.G., C.A.P.), University of Leicester, Leicester, United Kingdom; Molecular Discovery Research, GlaxoSmithKline R&D, Harlow, Essex, United Kingdom (D.J.T.); Department of Pharmacology and Toxicology, University of Mansoura, Egypt (G.S.G.S.); Essen Bioscience Ltd., Welwyn Garden City, UK (D.J.T.); School of Clinical Sciences, University of Edinburgh, United Kingdom (D.M.P.)
| | - Catrin A Pritchard
- Department of Cell Physiology and Pharmacology (D.M.P., G.S.G.S., C.E.P., R.A.J.C., J.S.M.) and Department of Biochemistry (S.G., C.A.P.), University of Leicester, Leicester, United Kingdom; Molecular Discovery Research, GlaxoSmithKline R&D, Harlow, Essex, United Kingdom (D.J.T.); Department of Pharmacology and Toxicology, University of Mansoura, Egypt (G.S.G.S.); Essen Bioscience Ltd., Welwyn Garden City, UK (D.J.T.); School of Clinical Sciences, University of Edinburgh, United Kingdom (D.M.P.)
| | - R A John Challiss
- Department of Cell Physiology and Pharmacology (D.M.P., G.S.G.S., C.E.P., R.A.J.C., J.S.M.) and Department of Biochemistry (S.G., C.A.P.), University of Leicester, Leicester, United Kingdom; Molecular Discovery Research, GlaxoSmithKline R&D, Harlow, Essex, United Kingdom (D.J.T.); Department of Pharmacology and Toxicology, University of Mansoura, Egypt (G.S.G.S.); Essen Bioscience Ltd., Welwyn Garden City, UK (D.J.T.); School of Clinical Sciences, University of Edinburgh, United Kingdom (D.M.P.)
| | - John S Mitcheson
- Department of Cell Physiology and Pharmacology (D.M.P., G.S.G.S., C.E.P., R.A.J.C., J.S.M.) and Department of Biochemistry (S.G., C.A.P.), University of Leicester, Leicester, United Kingdom; Molecular Discovery Research, GlaxoSmithKline R&D, Harlow, Essex, United Kingdom (D.J.T.); Department of Pharmacology and Toxicology, University of Mansoura, Egypt (G.S.G.S.); Essen Bioscience Ltd., Welwyn Garden City, UK (D.J.T.); School of Clinical Sciences, University of Edinburgh, United Kingdom (D.M.P.)
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Herrmann S, Ninkovic M, Kohl T, Lörinczi É, Pardo LA. Cortactin controls surface expression of the voltage-gated potassium channel K(V)10.1. J Biol Chem 2012; 287:44151-63. [PMID: 23144454 PMCID: PMC3531731 DOI: 10.1074/jbc.m112.372540] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
KV10.1 is a voltage-gated potassium channel aberrantly expressed in many cases of cancer, and participates in cancer initiation and tumor progression. Its action as an oncoprotein can be inhibited by a functional monoclonal antibody, indicating a role for channels located at the plasma membrane, accessible to the antibody. Cortactin is an actin-interacting protein implicated in cytoskeletal architecture and often amplified in several types of cancer. In this study, we describe a physical and functional interaction between cortactin and KV10.1. Binding of these two proteins occurs between the C terminus of KV10.1 and the proline-rich domain of cortactin, regions targeted by many post-translational modifications. This interaction is specific for KV10.1 and does not occur with KV10.2. Cortactin controls the abundance of KV10.1 at the plasma membrane and is required for functional expression of KV10.1 channels.
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Affiliation(s)
- Solveig Herrmann
- Oncophysiology Group, Max-Planck Institute of Experimental Medicine, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
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Ding XW, Yang WB, Gao S, Wang W, Li Z, Hu WM, Li JJ, Luo HS. Prognostic significance of hERG1 expression in gastric cancer. Dig Dis Sci 2010; 55:1004-10. [PMID: 19495974 DOI: 10.1007/s10620-009-0834-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Accepted: 04/30/2009] [Indexed: 01/12/2023]
Abstract
Previous studies have demonstrated that human ether-à-go-go-related potassium channel (hERG1) is highly expressed in many tumor cell lines, as well as in primary human cancers, and, hence, have a critical role in cell cycle progress and proliferation. In this study, hERG1 expression was investigated in gastric cancer by immunohistochemistry and/or reverse transcription polymerase chain reaction (RT-PCR). It was discovered that hERG1, which was negatively expressed in surrounding non-tumor tissues, switched to aberrantly positive expression in gastric cancer. Statistically, there were significant differences in hERG1 protein expression according to factors such as serosal invasion, venous invasion, lymph node metastases, other organ metastases, and stage. The mean survival time for the hERG1-positive expression group was significantly shorter than the negative group, the survival rates for the positive group were significantly lower than the negative group, and hERG1 expression was found to be an independent prognostic factor. In summary, hERG1 channel was proved to be a potential biomarker for gastric cancer invasion and survival.
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Affiliation(s)
- Xiang-Wu Ding
- Department of Gastroenterology, Xiangfan Central Hospital, Xiangfan, 441021, People's Republic of China.
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Yang Y, Wu X, Gui P, Wu J, Sheng JZ, Ling S, Braun AP, Davis GE, Davis MJ. Alpha5beta1 integrin engagement increases large conductance, Ca2+-activated K+ channel current and Ca2+ sensitivity through c-src-mediated channel phosphorylation. J Biol Chem 2009; 285:131-41. [PMID: 19887442 DOI: 10.1074/jbc.m109.033506] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Large conductance, calcium-activated K(+) (BK) channels are important regulators of cell excitability and recognized targets of intracellular kinases. BK channel modulation by tyrosine kinases, including focal adhesion kinase and c-src, suggests their potential involvement in integrin signaling. Recently, we found that fibronectin, an endogenous alpha5beta1 integrin ligand, enhances BK channel current through both Ca(2+)- and phosphorylation-dependent mechanisms in vascular smooth muscle. Here, we show that macroscopic currents from HEK 293 cells expressing murine BK channel alpha-subunits (mSlo) are acutely potentiated following alpha5beta1 integrin activation. The effect occurs in a Ca(2+)-dependent manner, 1-3 min after integrin engagement. After integrin activation, normalized conductance-voltage relations for mSlo are left-shifted at free Ca(2+) concentrations >or=1 microm. Overexpression of human c-src with mSlo, in the absence of integrin activation, leads to similar shifts in mSlo Ca(2+) sensitivity, whereas overexpression of catalytically inactive c-src blocks integrin-induced potentiation. However, neither integrin activation nor c-src overexpression potentiates current in BK channels containing a point mutation at Tyr-766. Biochemical tests confirmed the critical importance of residue Tyr-766 in integrin-induced channel phosphorylation. Thus, BK channel activity is enhanced by alpha5beta1 integrin activation, likely through an intracellular signaling pathway involving c-src phosphorylation of the channel alpha-subunit at Tyr-766. The net result is increased current amplitude, enhanced Ca(2+) sensitivity, and rate of activation of the BK channel, which would collectively promote smooth muscle hyperpolarization in response to integrin-extracellular matrix interactions.
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Affiliation(s)
- Yan Yang
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, Missouri 65212, USA
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12
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Wei JF, Wei L, Zhou X, Lu ZY, Francis K, Hu XY, Liu Y, Xiong WC, Zhang X, Banik NL, Zheng SS, Yu SP. Formation of Kv2.1-FAK complex as a mechanism of FAK activation, cell polarization and enhanced motility. J Cell Physiol 2008; 217:544-57. [PMID: 18615577 DOI: 10.1002/jcp.21530] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Focal adhesion kinase (FAK) plays key roles in cell adhesion and migration. We now report that the delayed rectifier Kv2.1 potassium channel, through its LD-like motif in N-terminus, may interact with FAK and enhance phosphorylation of FAK(397) and FAK(576/577). Overlapping distribution of Kv2.1 and FAK was observed on soma and proximal dendrites of cortical neurons. FAK expression promotes a polarized membrane distribution of the Kv2.1 channel. In Kv2.1-transfected CHO cells, formation of the Kv2.1-FAK complex was stimulated by fibronectin/integrin and inhibited by the K(+) channel blocker tetraethylammonium (TEA). FAK phosphorylation was minimized by shRNA knockdown of the Kv2.1 channel, point mutations of the N-terminus, and TEA, respectively. Cell migration morphology was altered by Kv2.1 knockdown or TEA, hindering cell migration activity. In wound healing tests in vitro and a traumatic injury animal model, Kv2.1 expression and co-localization of Kv2.1 and FAK significantly enhanced directional cell migration and wound closure. It is suggested that the Kv2.1 channel may function as a promoting signal for FAK activation and cell motility.
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Affiliation(s)
- Jian-Feng Wei
- Key Laboratory of Combined Multi-organ Transplantation of Ministry of Health China, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
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The alpha9beta1 integrin enhances cell migration by polyamine-mediated modulation of an inward-rectifier potassium channel. Proc Natl Acad Sci U S A 2008; 105:7188-93. [PMID: 18480266 DOI: 10.1073/pnas.0708044105] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The alpha9beta1 integrin accelerates cell migration through binding of spermidine/spermine acetyltransferase (SSAT) to the alpha9 cytoplasmic domain. We now show that SSAT enhances alpha9-mediated migration specifically through catabolism of spermidine and/or spermine. Because spermine and spermidine are effective blockers of K(+) ion efflux through inward-rectifier K(+) (Kir) channels, we examined the involvement of Kir channels in this pathway. The Kir channel inhibitor, barium, or knockdown of a single subunit, Kir4.2, specifically inhibited alpha9-dependent cell migration. alpha9beta1 and Kir4.2 colocalized in focal adhesions at the leading edge of migrating cells and inhibition or knockdown of Kir4.2 caused reduced persistence and an increased number of lamellipodial extensions in cells migrating on an alpha9beta1 ligand. These results identify a pathway through which the alpha9 integrin subunit stimulates cell migration by localized polyamine catabolism and modulation of Kir channel function.
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Suh KS, Mutoh M, Mutoh T, Li L, Ryscavage A, Crutchley JM, Dumont RA, Cheng C, Yuspa SH. CLIC4 mediates and is required for Ca2+-induced keratinocyte differentiation. J Cell Sci 2007; 120:2631-40. [PMID: 17636002 DOI: 10.1242/jcs.002741] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Keratinocyte differentiation requires integrating signaling among intracellular ionic changes, kinase cascades, sequential gene expression, cell cycle arrest, and programmed cell death. We now show that Cl(-) intracellular channel 4 (CLIC4) expression is increased in both mouse and human keratinocytes undergoing differentiation induced by Ca(2+), serum and the protein kinase C (PKC)-activator, 12-O-tetradecanoyl-phorbol-13-acetate (TPA). Elevation of CLIC4 is associated with signaling by PKCdelta, and knockdown of CLIC4 protein by antisense or shRNA prevents Ca(2+)-induced keratin 1, keratin 10 and filaggrin expression and cell cycle arrest in differentiating keratinocytes. CLIC4 is cytoplasmic in actively proliferating keratinocytes in vitro, but the cytoplasmic CLIC4 translocates to the nucleus in keratinocytes undergoing growth arrest by differentiation, senescence or transforming growth factor beta (TGFbeta) treatment. Targeting CLIC4 to the nucleus of keratinocytes via adenoviral transduction increases nuclear Cl(-) content and enhances expression of differentiation markers in the absence of elevated Ca(2+). In vivo, CLIC4 is localized to the epidermis in mouse and human skin, where it is predominantly nuclear in quiescent cells. These results suggest that CLIC4 participates in epidermal homeostasis through both alterations in the level of expression and subcellular localization. Nuclear CLIC4, possibly by altering the Cl(-) and pH of the nucleus, contributes to cell cycle arrest and the specific gene expression program associated with keratinocyte terminal differentiation.
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Affiliation(s)
- Kwang S Suh
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
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15
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Toral C, Mendoza-Garrido ME, Azorín E, Hernández-Gallegos E, Gomora JC, Delgadillo DM, Solano-Agama C, Camacho J. Effect of extracellular matrix on adhesion, viability, actin cytoskeleton and K+ currents of cells expressing human ether à go-go channels. Life Sci 2007; 81:255-65. [PMID: 17586530 DOI: 10.1016/j.lfs.2007.05.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2006] [Revised: 05/12/2007] [Accepted: 05/18/2007] [Indexed: 10/23/2022]
Abstract
Ether à go-go (EAG) potassium channels possess oncogenic properties and have gained great interest as research tools for cancer detection and therapy. Besides, EAG electrophysiological properties are regulated through the cell cycle and determined by cytoskeletal interactions. Thus, because of the pivotal role of extracellular matrix (ECM) and cytoskeleton in cancer progression, we studied the effect of ECM components on adhesion, viability, actin organization and EAG currents in wild-type CHO cells (CHO-wt) and cells expressing human EAG channels (CHO-hEAG). At short incubation times, adhesion and viability of CHO-hEAG cells grown on collagen, heparin or poly-lysine were lower than CHO-wt cells, however, only CHO-hEAG sustained growing under total serum starvation. CHO-hEAG cells grown on poly-lysine did not organize their cytoskeleton but when grown on collagen or fibronectin displayed lamellipodia and stress fibers, respectively. Interestingly, EAG expressing cells displayed special actin structures suggesting a dynamic actin cytoskeleton, such structures were not exhibited by wild-type cells. EAG current density was significantly lower in cells grown on collagen at short incubation times. Finally, we studied potential associations between hEAG channels and integrins or actin filaments by confocal microscopy. No association between beta1-integrins and hEAG channels was found, however, a very strong co-localization was observed between hEAG channels and actin filaments, supported by immunoblot experiments in which hEAG channels were found in the insoluble fraction (associated to cytoskeleton). Our results suggest ECM components as potential modulators of oncogenic human-EAG expressing cells and emphasize the relationship between potassium channels, cytoskeleton, ECM and cancer.
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Affiliation(s)
- Claudia Toral
- Pharmacology Section, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
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16
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Furlan F, Taccola G, Grandolfo M, Guasti L, Arcangeli A, Nistri A, Ballerini L. ERG conductance expression modulates the excitability of ventral horn GABAergic interneurons that control rhythmic oscillations in the developing mouse spinal cord. J Neurosci 2007; 27:919-28. [PMID: 17251434 PMCID: PMC6672895 DOI: 10.1523/jneurosci.4035-06.2007] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
During antenatal development, the operation and maturation of mammalian spinal networks strongly depend on the activity of ventral horn GABAergic interneurons that mediate excitation first and inhibition later. Although the functional consequence of GABA actions may depend on maturational processes in target neurons, it is also likely that evolving changes in GABAergic transmission require fine-tuning in GABA release, probably via certain intrinsic mechanisms regulating GABAergic neuron excitability at different embryonic stages. Nevertheless, it has not been possible, to date, to identify certain ionic conductances upregulated or downregulated before birth in such cells. By using an experimental model with either mouse organotypic spinal cultures or isolated spinal cord preparations, the present study examined the role of the ERG current (I(K(ERG))), a potassium conductance expressed by developing, GABA-immunoreactive spinal neurons. In organotypic cultures, only ventral interneurons with fast adaptation and GABA immunoreactivity, and only after 1 week in culture, were transformed into high-frequency bursters by E4031, a selective inhibitor of I(K(ERG)) that also prolonged and made more regular spontaneous bursts. In the isolated spinal cord in which GABA immunoreactivity and m-erg mRNA were colocalized in interneurons, ventral root rhythms evoked by NMDA plus 5-hydroxytryptamine were stabilized and synchronized by E4031. All of these effects were lost after 2 weeks in culture or before birth in coincidence with decreased m-erg expression. These data suggest that, during an early stage of spinal cord development, the excitability of GABAergic ventral interneurons important for circuit maturation depended, at least in part, on the function of I(K(ERG)).
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Affiliation(s)
- Francesco Furlan
- Physiology and Pathology Department, Center for Neuroscience B.R.A.I.N., University of Trieste, 34127 Trieste, Italy
| | - Giuliano Taccola
- Neurobiology Sector, International School for Advanced Studies, 34014 Trieste, Italy, and SPINAL Project, Udine
| | - Micaela Grandolfo
- Neurobiology Sector, International School for Advanced Studies, 34014 Trieste, Italy, and SPINAL Project, Udine
| | - Leonardo Guasti
- Department of Experimental Pathology and Oncology, University of Firenze, 50134 Firenze, Italy
| | - Annarosa Arcangeli
- Department of Experimental Pathology and Oncology, University of Firenze, 50134 Firenze, Italy
| | - Andrea Nistri
- Neurobiology Sector, International School for Advanced Studies, 34014 Trieste, Italy, and SPINAL Project, Udine
| | - Laura Ballerini
- Physiology and Pathology Department, Center for Neuroscience B.R.A.I.N., University of Trieste, 34127 Trieste, Italy
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17
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Phartiyal P, Jones EMC, Robertson GA. Heteromeric assembly of human ether-à-go-go-related gene (hERG) 1a/1b channels occurs cotranslationally via N-terminal interactions. J Biol Chem 2007; 282:9874-9882. [PMID: 17272276 DOI: 10.1074/jbc.m610875200] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Alternate transcripts of the human ether-à-go-go-related gene (hERG1) encode two subunits, hERG 1a and 1b, which form potassium channels regulating cardiac repolarization, neuronal firing frequency, and neoplastic cell growth. The 1a and 1b subunits are identical except for their unique, cytoplasmic N termini, and they readily co-assemble in heterologous and native systems. We tested the hypothesis that interactions of nascent N termini promote heteromeric assembly of 1a and 1b subunits. We found that 1a and 1b N-terminal fragments bind in a direct and dose-dependent manner. hERG1 hetero-oligomerization occurs in the endoplasmic reticulum where co-expression of N-terminal fragments with hERG1 subunits disrupted oligomerization and core glycosylation. The disruption of core glycosylation, a cotranslational event, allows us to pinpoint these N-terminal interactions to the earliest steps in biogenesis. Thus, N-terminal interactions mediate hERG 1a/1b assembly, a process whose perturbation may represent a new mechanism for disease.
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Affiliation(s)
- Pallavi Phartiyal
- Department of Physiology, University of Wisconsin, Madison, Wisconsin 53711; Cellular and Molecular Biology Program, University of Wisconsin, Madison, Wisconsin 53711
| | - Eugenia M C Jones
- Department of Physiology, University of Wisconsin, Madison, Wisconsin 53711
| | - Gail A Robertson
- Department of Physiology, University of Wisconsin, Madison, Wisconsin 53711.
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18
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Camacho J. Ether à go-go potassium channels and cancer. Cancer Lett 2006; 233:1-9. [PMID: 16473665 DOI: 10.1016/j.canlet.2005.02.016] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2005] [Accepted: 02/14/2005] [Indexed: 12/28/2022]
Abstract
Ion channels play important roles in health and disease. In the last few years, an interesting relationship between potassium channels and cancer has evolved. Especially, members of the ether à go-go (EAG) potassium channels family have gained interest as research tools for detection and therapy of different cancers. This review will summarize most of the findings relating EAG channels and cancer, focusing on mRNA expression in tissues, oncogenic properties, modulation and pharmacology. Plausible scenarios on the cellular mechanisms of EAG oncogenicity will be discussed.
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Affiliation(s)
- Javier Camacho
- Pharmacology Section, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Avenida Instituto Politécnico Nacional 2508, México, DF 07360, México.
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