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The Multifaceted Role of Connexins in Tumor Microenvironment Initiation and Maintenance. BIOLOGY 2023; 12:biology12020204. [PMID: 36829482 PMCID: PMC9953436 DOI: 10.3390/biology12020204] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 01/19/2023] [Accepted: 01/26/2023] [Indexed: 01/31/2023]
Abstract
Today's research on the processes of carcinogenesis and the vital activity of tumor tissues implies more attention be paid to constituents of the tumor microenvironment and their interactions. These interactions between cells in the tumor microenvironment can be mediated via different types of protein junctions. Connexins are one of the major contributors to intercellular communication. They form the gap junctions responsible for the transfer of ions, metabolites, peptides, miRNA, etc., between neighboring tumor cells as well as between tumor and stromal cells. Connexin hemichannels mediate purinergic signaling and bidirectional molecular transport with the extracellular environment. Additionally, connexins have been reported to localize in tumor-derived exosomes and facilitate the release of their cargo. A large body of evidence implies that the role of connexins in cancer is multifaceted. The pro- or anti-tumorigenic properties of connexins are determined by their abundance, localization, and functionality as well as their channel assembly and non-channel functions. In this review, we have summarized the data on the contribution of connexins to the formation of the tumor microenvironment and to cancer initiation and progression.
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Heimerl M, Sieve I, Ricke-Hoch M, Erschow S, Battmer K, Scherr M, Hilfiker-Kleiner D. Neuraminidase-1 promotes heart failure after ischemia/reperfusion injury by affecting cardiomyocytes and invading monocytes/macrophages. Basic Res Cardiol 2020; 115:62. [PMID: 32975669 PMCID: PMC7519006 DOI: 10.1007/s00395-020-00821-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 09/01/2020] [Indexed: 12/31/2022]
Abstract
Neuraminidase (NEU)1 forms a multienzyme complex with beta-galactosidase (β-GAL) and protective-protein/cathepsin (PPC) A, which cleaves sialic-acids from cell surface glycoconjugates. We investigated the role of NEU1 in the myocardium after ischemia/reperfusion (I/R). Three days after inducing I/R, left ventricles (LV) of male mice (3 months-old) displayed upregulated neuraminidase activity and increased NEU1, β-GAL and PPCA expression. Mice hypomorphic for neu1 (hNEU1) had less neuraminidase activity, fewer pro-inflammatory (Lin−CD11b+F4/80+Ly-6Chigh), and more anti-inflammatory macrophages (Lin−CD11b+F4/80+Ly-6Clow) 3 days after I/R, and less LV dysfunction 14 days after I/R. WT mice transplanted with hNEU1-bone marrow (BM) and hNEU1 mice with WT-BM showed significantly better LV function 14 days after I/R compared with WT mice with WT-BM. Mice with a cardiomyocyte-specific NEU1 overexpression displayed no difference in inflammation 3 days after I/R, but showed increased cardiomyocyte hypertrophy, reduced expression and mislocalization of Connexin-43 in gap junctions, and LV dysfunction despite a similar infarct scar size to WT mice 14 days after I/R. The upregulation of NEU1 after I/R contributes to heart failure by promoting inflammation in invading monocytes/macrophages, enhancing cardiomyocyte hypertrophy, and impairing gap junction function, suggesting that systemic NEU1 inhibition may reduce heart failure after I/R.
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Affiliation(s)
- Maren Heimerl
- Molecular Cardiology, Department of Cardiology and Angiology, Hannover Medical School, Carl-Neuberg Str. 1, 30625, Hannover, Germany
| | - Irina Sieve
- Molecular Cardiology, Department of Cardiology and Angiology, Hannover Medical School, Carl-Neuberg Str. 1, 30625, Hannover, Germany
| | - Melanie Ricke-Hoch
- Molecular Cardiology, Department of Cardiology and Angiology, Hannover Medical School, Carl-Neuberg Str. 1, 30625, Hannover, Germany
| | - Sergej Erschow
- Molecular Cardiology, Department of Cardiology and Angiology, Hannover Medical School, Carl-Neuberg Str. 1, 30625, Hannover, Germany
| | - Karin Battmer
- Department of Hematology, Hemostasis, Oncology and Stem Cell Transplantation, Hannover Medical School, Carl-Neuberg-Str.1, 30625, Hannover, Germany
| | - Michaela Scherr
- Department of Hematology, Hemostasis, Oncology and Stem Cell Transplantation, Hannover Medical School, Carl-Neuberg-Str.1, 30625, Hannover, Germany
| | - Denise Hilfiker-Kleiner
- Molecular Cardiology, Department of Cardiology and Angiology, Hannover Medical School, Carl-Neuberg Str. 1, 30625, Hannover, Germany.
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Bauer TJ, Gombocz E, Wehland M, Bauer J, Infanger M, Grimm D. Insight in Adhesion Protein Sialylation and Microgravity Dependent Cell Adhesion-An Omics Network Approach. Int J Mol Sci 2020; 21:ijms21051749. [PMID: 32143440 PMCID: PMC7084616 DOI: 10.3390/ijms21051749] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 02/28/2020] [Accepted: 03/02/2020] [Indexed: 12/18/2022] Open
Abstract
The adhesion behavior of human tissue cells changes in vitro, when gravity forces affecting these cells are modified. To understand the mechanisms underlying these changes, proteins involved in cell-cell or cell-extracellular matrix adhesion, their expression, accumulation, localization, and posttranslational modification (PTM) regarding changes during exposure to microgravity were investigated. As the sialylation of adhesion proteins is influencing cell adhesion on Earth in vitro and in vivo, we analyzed the sialylation of cell adhesion molecules detected by omics studies on cells, which change their adhesion behavior when exposed to microgravity. Using a knowledge graph created from experimental omics data and semantic searches across several reference databases, we studied the sialylation of adhesion proteins glycosylated at their extracellular domains with regards to its sensitivity to microgravity. This way, experimental omics data networked with the current knowledge about the binding of sialic acids to cell adhesion proteins, its regulation, and interactions in between those proteins provided insights into the mechanisms behind our experimental findings, suggesting that balancing the sialylation against the de-sialylation of the terminal ends of the adhesion proteins' glycans influences their binding activity. This sheds light on the transition from two- to three-dimensional growth observed in microgravity, mirroring cell migration and cancer metastasis in vivo.
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Affiliation(s)
- Thomas J. Bauer
- Clinic for Plastic, Aesthetic and Hand Surgery, Otto-von-Guericke-University Magdeburg, D-39120 Magdeburg, Germany; (T.J.B.); (M.W.); (M.I.); (D.G.)
| | - Erich Gombocz
- Melissa Informatics, 2550 Ninth Street, Suite 114, Berkeley, CA 94710, USA;
| | - Markus Wehland
- Clinic for Plastic, Aesthetic and Hand Surgery, Otto-von-Guericke-University Magdeburg, D-39120 Magdeburg, Germany; (T.J.B.); (M.W.); (M.I.); (D.G.)
| | - Johann Bauer
- Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany
- Correspondence: ; Tel.: +49-89-85783803
| | - Manfred Infanger
- Clinic for Plastic, Aesthetic and Hand Surgery, Otto-von-Guericke-University Magdeburg, D-39120 Magdeburg, Germany; (T.J.B.); (M.W.); (M.I.); (D.G.)
| | - Daniela Grimm
- Clinic for Plastic, Aesthetic and Hand Surgery, Otto-von-Guericke-University Magdeburg, D-39120 Magdeburg, Germany; (T.J.B.); (M.W.); (M.I.); (D.G.)
- Department of Biomedicine, Aarhus University Hospital, DK-8000 Aarhus C, Denmark
- Department of Microgravity and Translational Regenerative Medicine, Otto von Guericke University, Pfälzer Platz, 39106 Magdeburg, Germany
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Li CH, Hao ML, Sun Y, Wang ZJ, Li JL. Ultrastructure of gap junction and Cx43 expression in gastric cancer tissues of the patients. Arch Med Sci 2020; 16:352-358. [PMID: 32190146 PMCID: PMC7069450 DOI: 10.5114/aoms.2020.92859] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 08/21/2017] [Indexed: 11/26/2022] Open
Abstract
INTRODUCTION Gap junctions are intercellular channels formed by connexin facilitating communication between cells by allowing transfer of ions and small signaling molecules. Connexin 43 (Cx43) is the most ubiquitous connexin in human tissues. Ample evidence suggests the role of gap junction and its connexins such as connexin 43 in human cancers including gastric cancer, which has an important place in the worldwide incidence of cancer and cancer-related deaths. Due to a number of contradictory studies and insufficient detailed examination in specific cancers, such as gastric cancer, more data on the role of gap junctions and their connexins such as Cx43 involved in gastric cancer remain necessary. MATERIAL AND METHODS Transmission electron microscopy, Western blotting and RT-PCR were used to show the ultrastructure damage of the gap junction in the gastric carcinoma tissue as well as the expression of Cx43 protein and mRNA, respectively. RESULTS Ultrastructure damage of the gap junction in gastric carcinoma tissue was shown while poorly differentiated tissue experienced greater damage. The expression of Cx43 protein and mRNA was higher in healthy gastric tissue than in carcinomatous gastric tissue (p < 0.05). There was higher expression of Cx43 protein and mRNA in high-medium differentiation than in poor differentiation (p < 0.05). Cx43 protein and mRNA expression is not statistically significant for different ages and sex (such as for > 56 and ≤ 56 years) (p > 0.05). CONCLUSIONS Ultrastructural changes of gap junctions with abnormal Cx43 expression are associated with occurrence and development of gastric cancer, which provides a new research direction for gastric cancer pathogenesis and targeted therapy.
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Affiliation(s)
- Chun-Hui Li
- Department of Pathology, The Affiliated Hospital of Chengde Medical College, Chengde, Hebei, China
| | - Mei-Ling Hao
- Department of Pathology, The Affiliated Hospital of Chengde Medical College, Chengde, Hebei, China
| | - Yu Sun
- Department of Pathology, The Affiliated Hospital of Chengde Medical College, Chengde, Hebei, China
| | - Zhu-Jun Wang
- Department of Pathology, The Affiliated Hospital of Chengde Medical College, Chengde, Hebei, China
| | - Jian-Ling Li
- Department of Pathology, The Affiliated Hospital of Chengde Medical College, Chengde, Hebei, China
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Chandler KB, Costello CE, Rahimi N. Glycosylation in the Tumor Microenvironment: Implications for Tumor Angiogenesis and Metastasis. Cells 2019; 8:E544. [PMID: 31195728 PMCID: PMC6627046 DOI: 10.3390/cells8060544] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 05/31/2019] [Accepted: 06/01/2019] [Indexed: 01/27/2023] Open
Abstract
Just as oncogene activation and tumor suppressor loss are hallmarks of tumor development, emerging evidence indicates that tumor microenvironment-mediated changes in glycosylation play a crucial functional role in tumor progression and metastasis. Hypoxia and inflammatory events regulate protein glycosylation in tumor cells and associated stromal cells in the tumor microenvironment, which facilitates tumor progression and also modulates a patient's response to anti-cancer therapeutics. In this review, we highlight the impact of altered glycosylation on angiogenic signaling and endothelial cell adhesion, and the critical consequences of these changes in tumor behavior.
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Affiliation(s)
- Kevin Brown Chandler
- Center for Biomedical Mass Spectrometry, Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA.
| | - Catherine E Costello
- Center for Biomedical Mass Spectrometry, Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA.
| | - Nader Rahimi
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA 02118, USA.
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Sialic Acid-Targeted Biointerface Materials and Bio-Applications. Polymers (Basel) 2017; 9:polym9070249. [PMID: 30970926 PMCID: PMC6432383 DOI: 10.3390/polym9070249] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 06/23/2017] [Accepted: 06/24/2017] [Indexed: 02/07/2023] Open
Abstract
Sialic acids (SAs) are typically found as terminal monosaccharides attached to cell surface glycoconjugates, which play crucial roles in various biological processes, and aberrant sialylation is closely associated with many diseases, particularly cancers. As SAs are overexpressed in tumor-associated glycoproteins, the recognition and specific binding of SA are crucial for monitoring, analyzing and controlling cancer cells, which would have a considerable impact on diagnostic and therapeutic application. However, both effective and selective recognition of SA on the cancer cell surface remains challenging. In recent years, SA-targeted biointerface materials have attracted great attention in various bio-applications, including cancer detection and imaging, drug delivery for cancer therapy and sialylated glycopeptide separation or enrichment. This review provides an overview of recent advances in SA-targeted biointerface materials and related bio-applications.
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Zou ZW, Chen HJ, Yu JL, Huang ZH, Fang S, Lin XH. Gap junction composed of connexin43 modulates 5‑fluorouracil, oxaliplatin and irinotecan resistance on colorectal cancers. Mol Med Rep 2016; 14:4893-4900. [PMID: 27748862 DOI: 10.3892/mmr.2016.5812] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 09/29/2016] [Indexed: 11/06/2022] Open
Abstract
Chemotherapy is one of the most commonly used therapeutic strategies for metastatic colon cancer. However, the development of resistance to chemotherapeutic agents limits their application in clinical use. The underlying mechanisms of this resistance development require further elucidation. The current study investigated the effects of connexin43 (Cx43) gap junctions on 5‑fluorouracil (5‑FU), oxaliplatin and irinotecan in colon cancer cells. Three different methods were used to manipulate Cx43 gap junction function: i) Cell culture at different densities; ii) pretreatment with a Cx43 specific inhibitor or enhancer; and iii) Cx43 gene knock‑down. Results indicated that the cell toxicity of 5‑FU, oxaliplatin and irinotecan was cell density‑dependent, which was mediated by gap junctions. Downregulation of Cx43 gap junction functioning attenuated 5‑FU, oxaliplatin and irinotecan toxicity in colon cancer cells, which was increased in cells treated with a Cx43 gap junction function enhancer. Thus, the results of the present study suggest that resistance to 5‑FU, oxaliplatin and irinotecan in colon cancer cells was relative to Cx43 expression loss as cancer developed, which may indicate a novel basis for therapeutic strategy development to combat drug resistance in numerous cell types, in addition to colon cancer cells.
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Affiliation(s)
- Zhao-Wei Zou
- Department of General Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong 510282, P.R. China
| | - Hai-Jin Chen
- Department of General Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong 510282, P.R. China
| | - Jin-Long Yu
- Department of General Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong 510282, P.R. China
| | - Zong-Hai Huang
- Department of General Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong 510282, P.R. China
| | - Shun Fang
- Department of Pathology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong 510282, P.R. China
| | - Xiao-Hua Lin
- Department of General Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong 510282, P.R. China
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Hoja-Łukowicz D, Przybyło M, Duda M, Pocheć E, Bubka M. On the trail of the glycan codes stored in cancer-related cell adhesion proteins. Biochim Biophys Acta Gen Subj 2016; 1861:3237-3257. [PMID: 27565356 DOI: 10.1016/j.bbagen.2016.08.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 07/22/2016] [Accepted: 08/14/2016] [Indexed: 12/14/2022]
Abstract
Changes in the profile of protein glycosylation are a hallmark of ongoing neoplastic transformation. A unique set of tumor-associated carbohydrate antigens expressed on the surface of malignant cells may serve as powerful diagnostic and therapeutic targets. Cell-surface proteins with altered glycosylation affect the growth, proliferation and survival of those cells, and contribute to their acquisition of the ability to migrate and invade. They may also facilitate tumor-induced immunosuppression and the formation of distant metastases. Deciphering the information encoded in these particular glycan portions of glycoconjugates may shed light on the mechanisms of cancer progression and metastasis. A majority of the related review papers have focused on overall changes in the patterns of cell-surface glycans in various cancers, without pinpointing the molecular carriers of these glycan structures. The present review highlights the ways in which particular tumor-associated glycan(s) coupled with a given membrane-bound protein influence neoplastic cell behavior during the development and progression of cancer. We focus on altered glycosylated cell-adhesion molecules belonging to the cadherin, integrin and immunoglobulin-like superfamilies, examined in the context of molecular interactions.
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Affiliation(s)
- Dorota Hoja-Łukowicz
- Department of Glycoconjugate Biochemistry, Institute of Zoology, Jagiellonian University, 9 Gronostajowa Street, 30-387 Krakow, Poland.
| | - Małgorzata Przybyło
- Department of Glycoconjugate Biochemistry, Institute of Zoology, Jagiellonian University, 9 Gronostajowa Street, 30-387 Krakow, Poland.
| | - Małgorzata Duda
- Department of Endocrinology, Institute of Zoology, Jagiellonian University, 9 Gronostajowa Street, 30-387 Krakow, Poland.
| | - Ewa Pocheć
- Department of Glycoconjugate Biochemistry, Institute of Zoology, Jagiellonian University, 9 Gronostajowa Street, 30-387 Krakow, Poland.
| | - Monika Bubka
- Department of Glycoconjugate Biochemistry, Institute of Zoology, Jagiellonian University, 9 Gronostajowa Street, 30-387 Krakow, Poland.
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Hervé JC, Derangeon M, Sarrouilhe D, Bourmeyster N. Influence of the scaffolding protein Zonula Occludens (ZOs) on membrane channels. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:595-604. [DOI: 10.1016/j.bbamem.2013.07.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 07/02/2013] [Accepted: 07/04/2013] [Indexed: 01/20/2023]
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De Bock M, Kerrebrouck M, Wang N, Leybaert L. Neurological manifestations of oculodentodigital dysplasia: a Cx43 channelopathy of the central nervous system? Front Pharmacol 2013; 4:120. [PMID: 24133447 PMCID: PMC3783840 DOI: 10.3389/fphar.2013.00120] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 09/02/2013] [Indexed: 12/30/2022] Open
Abstract
The coordination of tissue function is mediated by gap junctions (GJs) that enable direct cell–cell transfer of metabolic and electric signals. GJs are formed by connexins of which Cx43 is most widespread in the human body. In the brain, Cx43 GJs are mostly found in astroglia where they coordinate the propagation of Ca2+ waves, spatial K+ buffering, and distribution of glucose. Beyond its role in direct intercellular communication, Cx43 also forms unapposed, non-junctional hemichannels in the plasma membrane of glial cells. These allow the passage of several neuro- and gliotransmitters that may, combined with downstream paracrine signaling, complement direct GJ communication among glial cells and sustain glial-neuronal signaling. Mutations in the GJA1 gene encoding Cx43 have been identified in a rare, mostly autosomal dominant syndrome called oculodentodigital dysplasia (ODDD). ODDD patients display a pleiotropic phenotype reflected by eye, hand, teeth, and foot abnormalities, as well as craniofacial and bone malformations. Remarkably, neurological symptoms such as dysarthria, neurogenic bladder (manifested as urinary incontinence), spasticity or muscle weakness, ataxia, and epilepsy are other prominent features observed in ODDD patients. Over 10 mutations detected in patients diagnosed with neurological disorders are associated with altered functionality of Cx43 GJs/hemichannels, but the link between ODDD-related abnormal channel activities and neurologic phenotype is still elusive. Here, we present an overview on the nature of the mutants conveying structural and functional changes of Cx43 channels and discuss available evidence for aberrant Cx43 GJ and hemichannel function. In a final step, we examine the possibilities of how channel dysfunction may lead to some of the neurological manifestations of ODDD.
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Affiliation(s)
- Marijke De Bock
- Physiology Group, Department of Basic Medical Sciences, Ghent University Ghent, Belgium
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D'hondt C, Iyyathurai J, Vinken M, Rogiers V, Leybaert L, Himpens B, Bultynck G. Regulation of connexin- and pannexin-based channels by post-translational modifications. Biol Cell 2013; 105:373-98. [PMID: 23718186 DOI: 10.1111/boc.201200096] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 05/24/2013] [Indexed: 12/28/2022]
Abstract
Connexin (Cx) and pannexin (Panx) proteins form large conductance channels, which function as regulators of communication between neighbouring cells via gap junctions and/or hemichannels. Intercellular communication is essential to coordinate cellular responses in tissues and organs, thereby fulfilling an essential role in the spreading of signalling, survival and death processes. The functional properties of gap junctions and hemichannels are modulated by different physiological and pathophysiological stimuli. At the molecular level, Cxs and Panxs function as multi-protein channel complexes, regulating their channel localisation and activity. In addition to this, gap junctional channels and hemichannels are modulated by different post-translational modifications (PTMs), including phosphorylation, glycosylation, proteolysis, N-acetylation, S-nitrosylation, ubiquitination, lipidation, hydroxylation, methylation and deamidation. These PTMs influence almost all aspects of communicating junctional channels in normal cell biology and pathophysiology. In this review, we will provide a systematic overview of PTMs of communicating junction proteins and discuss their effects on Cx and Panx-channel activity and localisation.
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Affiliation(s)
- Catheleyne D'hondt
- Laboratory of Molecular and Cellular Signalling, Department Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg O/N 1, BE-3000, Leuven, Belgium.
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Li X, Pan JH, Song B, Xiong EQ, Chen ZW, Zhou ZS, Su YP. Suppression of CX43 expression by miR-20a in the progression of human prostate cancer. Cancer Biol Ther 2012; 13:890-8. [PMID: 22785209 DOI: 10.4161/cbt.20841] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The aberrant expression of microRNAs (miRNAs) has been found in various types of cancer. The present study found miR-20a to be significantly upregulated in prostate cancer compared with normal prostate tissues. The proliferation and colony formation assays revealed that the downregulation of miR-20a by miR-20a inhibitor suppresses the proliferation of MDA-PCa-2b cells in vitro and also inhibits tumor growth in vivo. Furthermore, a gap junction protein, α 1 (CX43), was identified as a direct target gene of miR-20a. The upregulation of CX43 was detected in MDA-PCa-2b cells after treatment with miR-20a inhibitor both in vitro and in vivo. In conclusion, the findings show that miR-20a significantly contributes to the progression of prostate cancer by targeting CX43.
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Affiliation(s)
- Xin Li
- Urologic Institute of PLA, Southwest Hospital, Third Military Medical University, Chongqing, China
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Sialylation and fucosylation of epidermal growth factor receptor suppress its dimerization and activation in lung cancer cells. Proc Natl Acad Sci U S A 2011; 108:11332-7. [PMID: 21709263 DOI: 10.1073/pnas.1107385108] [Citation(s) in RCA: 301] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Protein glycosylation is an important posttranslational process, which regulates protein folding and functional expression. Studies have shown that abnormal glycosylation in tumor cells affects cancer progression and malignancy. In the current study, we have identified sialylated proteins using an alkynyl sugar probe in two different lung cancer cell lines, CL1-0 and CL1-5 with distinct invasiveness derived from the same parental cell line. Among the identified sialylated proteins, epidermal growth factor receptor (EGFR) was chosen to understand the effect of sialylation on its function. We have determined the differences in glycan sequences of EGFR in both cells and observed higher sialylation and fucosylation of EGFR in CL1-5 than in CL1-0. Further study suggested that overexpression of sialyltransferases in CL1-5 and α1,3-fucosyltransferases (FUT4 or FUT6) in CL1-5 and A549 cells would suppress EGFR dimerization and phosphorylation upon EGF treatment, as compared to the control and CL1-0 cells. Such modulating effects on EGFR dimerization were further confirmed by sialidase or fucosidase treatment. Thus, increasing sialylation and fucosylation could attenuate EGFR-mediated invasion of lung cancer cells. However, incorporation of the core fucose by α1,6-fucosylatransferase (FUT8) would promote EGFR dimerization and phosphorylation.
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