1
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Dunn P, Annamdevula NS, Leavesley SJ, Rich TC, Phan AV. A two-dimensional finite element model of intercellular cAMP signaling through gap junction channels. J Biomech 2023; 152:111588. [PMID: 37094384 PMCID: PMC10173664 DOI: 10.1016/j.jbiomech.2023.111588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 04/02/2023] [Accepted: 04/11/2023] [Indexed: 04/26/2023]
Abstract
While cyclic adenosine monophosphate (cAMP) is typically considered an intracellular signal, it has been shown to spread between adjacent cells through connexin-based gap junction channels, promoting gap junctional intercellular communication (GJIC). Gap junction-mediated signaling is critical for the coordinated function of many tissues, and have been linked with cardiovascular disease, neurogenerative disease, and cancers. In particular, it plays a complex role in tumor suppression or promotion. This work introduces a two-dimensional finite element model that can describe intercellular cAMP signaling in the presence of gap junctions on membrane interfaces. The model was utilized to simulate cAMP transfer through one and two gap junction channels on the interface of a cluster of two pulmonary microvascular endothelial cells. The simulation results were found to generally agree with what has been observed in the literature in terms of GJIC. The research outcomes suggest that the proposed model can be employed to evaluate the permeability properties of a gap junction channel if its cAMP volumetric flow rate can be experimentally measured.
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Affiliation(s)
- P Dunn
- Department of Mechanical, Aerospace and Biomedical Engineering, University of South Alabama, Mobile, AL 36688, USA
| | - N S Annamdevula
- Center for Lung Biology & Department of Pharmacology University of South Alabama, Mobile, AL 36688, USA
| | - S J Leavesley
- Center for Lung Biology & Department of Pharmacology University of South Alabama, Mobile, AL 36688, USA; Department of Chemical and Biomolecular Engineering, University of South Alabama, Mobile, AL 36688, USA
| | - T C Rich
- Center for Lung Biology & Department of Pharmacology University of South Alabama, Mobile, AL 36688, USA
| | - A-V Phan
- Department of Mechanical, Aerospace and Biomedical Engineering, University of South Alabama, Mobile, AL 36688, USA.
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2
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Zhou M, Zheng M, Zhou X, Tian S, Yang X, Ning Y, Li Y, Zhang S. The roles of connexins and gap junctions in the progression of cancer. Cell Commun Signal 2023; 21:8. [PMID: 36639804 PMCID: PMC9837928 DOI: 10.1186/s12964-022-01009-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 12/03/2022] [Indexed: 01/15/2023] Open
Abstract
Gap junctions (GJs), which are composed of connexins (Cxs), provide channels for direct information exchange between cells. Cx expression has a strong spatial specificity; however, its influence on cell behavior and information exchange between cells cannot be ignored. A variety of factors in organisms can modulate Cxs and subsequently trigger a series of responses that have important effects on cellular behavior. The expression and function of Cxs and the number and function of GJs are in dynamic change. Cxs have been characterized as tumor suppressors in the past, but recent studies have highlighted the critical roles of Cxs and GJs in cancer pathogenesis. The complex mechanism underlying Cx and GJ involvement in cancer development is a major obstacle to the evolution of therapy targeting Cxs. In this paper, we review the post-translational modifications of Cxs, the interactions of Cxs with several chaperone proteins, and the effects of Cxs and GJs on cancer. Video Abstract.
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Affiliation(s)
- Mingming Zhou
- grid.265021.20000 0000 9792 1228Graduate School, Tianjin Medical University, Tianjin, 300070 People’s Republic of China
| | - Minying Zheng
- Department of Pathology, Tianjin Union Medical Center, Nankai University, Tianjin, 300121 People’s Republic of China
| | - Xinyue Zhou
- grid.265021.20000 0000 9792 1228Graduate School, Tianjin Medical University, Tianjin, 300070 People’s Republic of China
| | - Shifeng Tian
- grid.265021.20000 0000 9792 1228Graduate School, Tianjin Medical University, Tianjin, 300070 People’s Republic of China
| | - Xiaohui Yang
- grid.216938.70000 0000 9878 7032Nankai University School of Medicine, Nankai University, Tianjin, 300071 People’s Republic of China
| | - Yidi Ning
- grid.216938.70000 0000 9878 7032Nankai University School of Medicine, Nankai University, Tianjin, 300071 People’s Republic of China
| | - Yuwei Li
- grid.417031.00000 0004 1799 2675Department of Colorectal Surgery, Tianjin Union Medical Center, Tianjin, 300121 People’s Republic of China
| | - Shiwu Zhang
- Department of Pathology, Tianjin Union Medical Center, Nankai University, Tianjin, 300121 People’s Republic of China
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3
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Ugur D, Gungul TB, Yucel S, Ozcivici E, Yalcin-Ozuysal O, Mese G. Connexin 32 overexpression increases proliferation, reduces gap junctional intercellular communication, motility and epithelial-to-mesenchymal transition in Hs578T breast cancer cells. J Cell Commun Signal 2022; 16:361-376. [PMID: 35781670 DOI: 10.1007/s12079-021-00665-9] [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: 04/01/2021] [Accepted: 12/14/2021] [Indexed: 11/29/2022] Open
Abstract
Connexins (Cx) are primary components of gap junctions that selectively allow molecules to be exchanged between adjacent cells, regulating multiple cellular functions. Along with their channel forming functions, connexins play a variety of roles in different stages of tumorigenesis and their roles in tumor initiation and progression is isoform- and tissue-specific. While Cx26 and Cx43 were downregulated during breast tumorigenesis, Cx32 was accumulated in the cytoplasm of the cells in lymph node metastasis of breast cancers and Cx32 was further upregulated in metastasis. Cx32's effect on cell proliferation, gap junctional communication, hemichannel activity, cellular motility and epithelial-to-mesenchymal transition (EMT) were investigated by overexpressing Cx32 in Hs578T and MCF7 breast cancer cells. Additionally, the expression and localization of Cx26 and Cx43 upon Cx32 overexpression were examined by Western blot and immunostaining experiments, respectively. We observed that MCF7 cells had endogenous Cx32 while Hs578T cells did not and when Cx32 was overexpressed in these cells, it caused a significant increase in the percentages of Hs578T cells at the S phase in addition to increasing their proliferation. Further, while Cx32 overexpression did not induce hemichannel activity in either cell, it decreased gap junctional communication between Hs578T cells. Additionally, Cx32 was mainly observed in the cytoplasm in both cells, where it did not form gap junction plaques but Cx32 overexpression reduced Cx43 levels without affecting Cx26. Moreover, migration and invasion potentials of Hs578T and migration in MCF7 were reduced upon Cx32 overexpression. Finally, the protein level of mesenchymal marker N-cadherin decreased while epithelial marker ZO-1 and E-cadherin increased in Hs578T cells. We observed that Cx32 overexpression altered cell proliferation, communication, migration and EMT in Hs578T, suggesting a tumor suppressor role in these cells while it had minor effects on MCF7 cells.
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Affiliation(s)
- Deniz Ugur
- Department of Molecular Biology and Genetics, Izmir Institute of Technology, Urla, Izmir, 35430, Turkey.,Department of Molecular Biology and Genetics, Avrasya University, Trabzon, Turkey
| | - Taha Bugra Gungul
- Department of Molecular Biology and Genetics, Izmir Institute of Technology, Urla, Izmir, 35430, Turkey
| | - Simge Yucel
- Department of Molecular Biology and Genetics, Izmir Institute of Technology, Urla, Izmir, 35430, Turkey
| | - Engin Ozcivici
- Department of Bioengineering, Izmir Institute of Technology, Urla, Izmir, Turkey
| | - Ozden Yalcin-Ozuysal
- Department of Molecular Biology and Genetics, Izmir Institute of Technology, Urla, Izmir, 35430, Turkey
| | - Gulistan Mese
- Department of Molecular Biology and Genetics, Izmir Institute of Technology, Urla, Izmir, 35430, Turkey.
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4
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Valiunas V, Gordon C, Valiuniene L, Devine D, Lin RZ, Cohen IS, Brink PR. Intercellular delivery of therapeutic oligonucleotides. J Drug Deliv Sci Technol 2022; 72:103404. [PMID: 36721641 PMCID: PMC9886232 DOI: 10.1016/j.jddst.2022.103404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
One promising approach to cancer therapeutics is to induce changes in gene expression that either reduce cancer cell proliferation or induce cancer cell death. Therefore, delivering oligonucleotides (siRNA/miRNA) that target specific genes or gene programs might have a potential therapeutic benefit. The aim of this study was to examine the potential of cell-based delivery of oligonucleotides to cancer cells via two naturally occurring intercellular pathways: gap junctions and vesicular/exosomal traffic. We utilized human mesenchymal stem cells (hMSCs) as delivery cells and chose to deliver in vitro two synthetic oligonucleotides, AllStars HS Cell Death siRNA and miR-16 mimic, as toxic (therapeutic) oligonucleotides targeting three cancer cell lines: prostate (PC3), pancreatic (PANC1) and cervical (HeLa). Both oligonucleotides dramatically reduced cell proliferation and/or induced cell death when transfected directly into target cells and delivery hMSCs. The delivery and target cells we chose express gap junction connexin 43 (Cx43) endogenously (PC3, PANC1, hMSC) or via stable transfection (HeLaCx43). Co-culture of hMSCs (transfected with either toxic oligonucleotide) with any of Cx43 expressing cancer cells induced target cell death (~20% surviving) or senescence (~85% proliferation reduction) over 96 hours. We eliminated gap junction-mediated delivery by using connexin deficient HeLaWT cells or knocking out endogenous Cx43 in PANC1 and PC3 cells via CRISPR/Cas9. Subsequently, all Cx43 deficient target cells co-cultured with the same toxic oligonucleotide loaded hMSCs proliferated, albeit at significantly slower rates, with cell number increasing on average ~2.2-fold (30% of control cells) over 96 hours. Our results show that both gap junction and vesicular/exosomal intercellular delivery pathways from hMSCs to target cancer cells deliver oligonucleotides and function to either induce cell death or significantly reduce their proliferation. Thus, hMSC-based cellular delivery is an effective method of delivering synthetic oligonucleotides that can significantly reduce tumor cell growth and should be further investigated as a possible approach to cancer therapy.
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Affiliation(s)
- Virginijus Valiunas
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Chris Gordon
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Laima Valiuniene
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Daniel Devine
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Richard Z Lin
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Ira S Cohen
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Peter R Brink
- Department of Physiology and Biophysics and the Institute for Molecular Cardiology Stony Brook University, Stony Brook, NY 11794-8661, USA
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5
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Ray A, Mehta PP. Cysteine residues in the C-terminal tail of connexin32 regulate its trafficking. Cell Signal 2021; 85:110063. [PMID: 34146657 DOI: 10.1016/j.cellsig.2021.110063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 05/26/2021] [Accepted: 06/14/2021] [Indexed: 12/24/2022]
Abstract
Gap junctions (GJs) are formed by the assembly of constituent transmembrane proteins called connexins (Cxs). Aberrations in this assembly of Cxs are observed in several genetic diseases as well as in cancers. Hence it becomes imperative to understand the molecular mechanisms underlying such assembly defect. The polarized cells in the epithelia express Connexin32 (Cx32). The C-terminal tail (CT) of Cx32 orchestrates several aspects of GJ dynamics, function and growth. The study here was aimed at determining if post-translational modifications, specifically, palmitoylation of cysteine residues, present in the CT of Cx32, has any effect on GJ assembly. The CT of Cx32 was found to harbor three cysteine residues, which are likely to be modified by palmitoylation. The study here has revealed for the first time that Cx32 is palmitoylated at cysteine 217 (C217) in cell line derived from prostate tumors. However, it was found that mutating C217 to alanine affected neither the trafficking nor the ability of Cx32 to assemble into GJs. Intriguingly, it was discovered that mutating cysteine 280 and 283, only in combination, blocked the trafficking of Cx32 from the trans-Golgi network to the cell surface. The mutants showed reduced stability due to enhanced lysosomal degradation. Overall, the findings reveal the importance of the two C-terminal cysteine residues of Cx32 in regulating its trafficking and stability and hence its ability to assemble into GJs.
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Affiliation(s)
- Anuttoma Ray
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA; Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA.
| | - Parmender P Mehta
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
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6
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Antagonistic Functions of Connexin 43 during the Development of Primary or Secondary Bone Tumors. Biomolecules 2020; 10:biom10091240. [PMID: 32859065 PMCID: PMC7565206 DOI: 10.3390/biom10091240] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/20/2020] [Accepted: 08/25/2020] [Indexed: 12/14/2022] Open
Abstract
Despite research and clinical advances during recent decades, bone cancers remain a leading cause of death worldwide. There is a low survival rate for patients with primary bone tumors such as osteosarcoma and Ewing’s sarcoma or secondary bone tumors such as bone metastases from prostate carcinoma. Gap junctions are specialized plasma membrane structures consisting of transmembrane channels that directly link the cytoplasm of adjacent cells, thereby enabling the direct exchange of small signaling molecules between cells. Discoveries of human genetic disorders due to genetic mutations in gap junction proteins (connexins) and experimental data using connexin knockout mice have provided significant evidence that gap-junctional intercellular communication (Gj) is crucial for tissue function. Thus, the dysfunction of Gj may be responsible for the development of some diseases. Gj is thus a main mechanism for tumor cells to communicate with other tumor cells and their surrounding microenvironment to survive and proliferate. If it is well accepted that a low level of connexin expression favors cancer cell proliferation and therefore primary tumor development, more evidence is suggesting that a high level of connexin expression stimulates various cellular process such as intravasation, extravasation, or migration of metastatic cells. If so, connexin expression would facilitate secondary tumor dissemination. This paper discusses evidence that suggests that connexin 43 plays an antagonistic role in the development of primary bone tumors as a tumor suppressor and secondary bone tumors as a tumor promoter.
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Endo D, Kaneko S, Ishii K, Kohno K, Sato A, Virgona N, Yano T. The Effect of Bowman-Birk Inhibitor from Soybeans on the Sensitivity of Prostate Cancer Stem-like Cells to Anti-androgen Agent. FOOD SCIENCE AND TECHNOLOGY RESEARCH 2020. [DOI: 10.3136/fstr.26.553] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Daiki Endo
- Graduate School of Food and Nutritional Sciences, Toyo University
| | - Saki Kaneko
- Graduate School of Food and Nutritional Sciences, Toyo University
| | - Kyota Ishii
- Faculty of Food and Nutritional Sciences and Toyo University
| | - Kakeru Kohno
- Graduate School of Food and Nutritional Sciences, Toyo University
- Institute of Life Innovation Studies, Toyo University
| | - Ayami Sato
- Institute of Life Innovation Studies, Toyo University
| | | | - Tomohiro Yano
- Graduate School of Food and Nutritional Sciences, Toyo University
- Faculty of Food and Nutritional Sciences and Toyo University
- Institute of Life Innovation Studies, Toyo University
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8
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The Potential Impact of Connexin 43 Expression on Bcl-2 Protein Level and Taxane Sensitivity in Head and Neck Cancers-In Vitro Studies. Cancers (Basel) 2019; 11:cancers11121848. [PMID: 31766723 PMCID: PMC6966683 DOI: 10.3390/cancers11121848] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 11/08/2019] [Accepted: 11/20/2019] [Indexed: 12/20/2022] Open
Abstract
The poor prognosis of head and neck squamous cell carcinoma (HNSCC) is partly due to the lack of reliable predictive markers. Connexin 43 (Cx43) protein and its cell-communication channels have been assigned tumor suppressor functions while the anti-apoptotic Bcl-2 (B-cell lymphoma-2) protein has been associated with negative prognostic significance in cancer. This study aimed to test the role of Cx43 protein on Bcl-2 expression, tumor progression and response to taxane-based treatment in HNSCC. Human papillomavirus (HPV) negative HNSCC cell lines were tested for paclitaxel sensitivity through measuring apoptosis induction, cell viability and changes in Cx43 and Bcl-2 levels using flow cytometry, cell viability assay, immunocytochemistry and western blot. Inhibition of Cx43 expression using siRNA increased Bcl-2 protein levels in SCC25 (tongue squamous cell carcinoma) cells, while forced Cx43 expression reduced Bcl-2 levels and supported paclitaxel cytotoxicity in FaDu (hypopharynx squamous cell carcinoma) cells. In vitro results were in line with protein expression and clinicopathological features tested in tissue microarray samples of HNSCC patients. Our data demonstrate that elevated Cx43 and reduced Bcl-2 levels may indicate HNSCC sensitivity to taxane-based treatments. On the contrary, silencing of the Cx43 gene GJA1 (gap junction protein alpha-1) can result in increased Bcl-2 expression and reduced paclitaxel efficiency. Clinical tumor-based analysis also confirmed the inverse correlation between Cx43 and Bcl-2 expression.
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9
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Direct Intercellular Communications and Cancer: A Snapshot of the Biological Roles of Connexins in Prostate Cancer. Cancers (Basel) 2019; 11:cancers11091370. [PMID: 31540089 PMCID: PMC6770088 DOI: 10.3390/cancers11091370] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 08/04/2019] [Accepted: 08/08/2019] [Indexed: 02/07/2023] Open
Abstract
Tissue homeostasis is the result of a complex intercellular network controlling the behavior of every cell for the survival of the whole organism. In mammalian tissues, cells do communicate via diverse long- and short-range communication mechanisms. While long-range communication involves hormones through blood circulation and neural transmission, short-range communication mechanisms include either paracrine diffusible factors or direct interactions (e.g., gap junctions, intercellular bridges and tunneling nanotubes) or a mixture of both (e.g., exosomes). Tumor growth represents an alteration of tissue homeostasis and could be the consequence of intercellular network disruption. In this network, direct short-range intercellular communication seems to be particularly involved. The first type of these intercellular communications thought to be involved in cancer progression were gap junctions and their protein subunits, the connexins. From these studies came the general assumption that global decreased connexin expression is correlated to tumor progression and increased cell proliferation. However, this assumption appeared more complicated by the fact that connexins may act also as pro-tumorigenic. Then, the concept that direct intercellular communication could be involved in cancer has been expanded to include new forms of intercellular communication such as tunneling nanotubes (TNTs) and exosomes. TNTs are intercellular bridges that allow free exchange of small molecules or even mitochondria depending on the presence of gap junctions. The majority of current research shows that such exchanges promote cancer progression by increasing resistance to hypoxia and chemotherapy. If exosomes are also involved in these mechanisms, more studies are needed to understand their precise role. Prostate cancer (PCa) represents a type of malignancy with one of the highest incidence rates worldwide. The precise role of these types of direct short-range intercellular communication has been considered in the progression of PCa. However, even though data are in favor of connexins playing a key role in PCa progression, a clear understanding of the role of TNTs and exosomes is needed to define their precise role in this malignancy. This review article summarizes the current view of the main mechanisms involved in short-range intercellular communication and their implications in cancer and delves into the biological, predictive and therapeutic role of connexins in PCa.
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Aasen T, Leithe E, Graham SV, Kameritsch P, Mayán MD, Mesnil M, Pogoda K, Tabernero A. Connexins in cancer: bridging the gap to the clinic. Oncogene 2019; 38:4429-4451. [PMID: 30814684 PMCID: PMC6555763 DOI: 10.1038/s41388-019-0741-6] [Citation(s) in RCA: 116] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 01/26/2019] [Accepted: 01/26/2019] [Indexed: 02/08/2023]
Abstract
Gap junctions comprise arrays of intercellular channels formed by connexin proteins and provide for the direct communication between adjacent cells. This type of intercellular communication permits the coordination of cellular activities and plays key roles in the control of cell growth and differentiation and in the maintenance of tissue homoeostasis. After more than 50 years, deciphering the links among connexins, gap junctions and cancer, researchers are now beginning to translate this knowledge to the clinic. The emergence of new strategies for connexin targeting, combined with an improved understanding of the molecular bases underlying the dysregulation of connexins during cancer development, offers novel opportunities for clinical applications. However, different connexin isoforms have diverse channel-dependent and -independent functions that are tissue and stage specific. This can elicit both pro- and anti-tumorigenic effects that engender significant challenges in the path towards personalised medicine. Here, we review the current understanding of the role of connexins and gap junctions in cancer, with particular focus on the recent progress made in determining their prognostic and therapeutic potential.
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Affiliation(s)
- Trond Aasen
- Translational Molecular Pathology, Vall d'Hebron Institute of Research (VHIR), Autonomous University of Barcelona, CIBERONC, Barcelona, Spain.
| | - Edward Leithe
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital and K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway
| | - Sheila V Graham
- MRC-University of Glasgow Centre for Virus Research, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Petra Kameritsch
- Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians-Universität München and Munich University Hospital, München, Germany
| | - María D Mayán
- CellCOM Research Group, Instituto de Investigación Biomédica de A Coruña (INIBIC), Servizo Galego de Saúde (SERGAS), University of A Coruña, A Coruña, Spain
| | - Marc Mesnil
- STIM Laboratory, Faculté des Sciences Fondamentales et Appliquées, Université de Poitiers, Poitiers, France
| | - Kristin Pogoda
- Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians-Universität München and Munich University Hospital, München, Germany
| | - Arantxa Tabernero
- Departamento de Bioquímica y Biología Molecular, Instituto de Neurociencias de Castilla y León (INCYL), Universidad de Salamanca, Salamanca, Spain.
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Scarano WR, Pinho CF, Pissinatti L, Gonçalves BF, Mendes LO, Campos SG. Cell junctions in the prostate: an overview about the effects of Endocrine Disrupting Chemicals (EDCS) in different experimental models. Reprod Toxicol 2018; 81:147-154. [DOI: 10.1016/j.reprotox.2018.08.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 07/30/2018] [Accepted: 08/02/2018] [Indexed: 12/20/2022]
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12
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Iikawa N, Yamamoto Y, Kawasaki Y, Nishijima-Matsunobu A, Suzuki M, Yamada T, Omori Y. Intrinsic Oncogenic Function of Intracellular Connexin26 Protein in Head and Neck Squamous Cell Carcinoma Cells. Int J Mol Sci 2018; 19:ijms19072134. [PMID: 30041406 PMCID: PMC6073371 DOI: 10.3390/ijms19072134] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Revised: 07/19/2018] [Accepted: 07/21/2018] [Indexed: 02/07/2023] Open
Abstract
It has long been known that the gap junction is down-regulated in many tumours. One of the downregulation mechanisms is the translocation of connexin, a gap junction protein, from cell membrane into cytoplasm, nucleus, or Golgi apparatus. Interestingly, as tumours progress and reinforce their malignant phenotype, the amount of aberrantly-localised connexin increases in different malignant tumours including oesophageal squamous cell carcinoma, thus suggesting that such an aberrantly-localised connexin should be oncogenic, although gap junctional connexins are often tumour-suppressive. To define the dual roles of connexin in head and neck squamous cell carcinoma (HNSCC), we introduced the wild-type connexin26 (wtCx26) or the mutant Cx26 (icCx26) gene, the product of which carries the amino acid sequence AKKFF, an endoplasmic reticulum-Golgi retention signal, at the C-terminus and is not sorted to cell membrane, into the human FaDu hypopharyngeal cancer cell line that had severely impaired the expression of connexin during carcinogenesis. wtCx26 protein was trafficked to the cell membrane and formed gap junction, which successfully exerted cell-cell communication. On the other hand, the icCx26 protein was co-localised with a Golgi marker, as revealed by immunofluorescence, and thus was retained on the way to the cell membrane. While the forced expression of wtCx26 suppressed both cell proliferation in vitro and tumorigenicity in mice in vivo, icCx26 significantly enhanced both cell proliferation and tumorigenicity compared with the mock control clones, indicating that an excessive accumulation of connexin protein in intracellular domains should be involved in cancer progression and that restoration of proper subcellular sorting of connexin might be a therapeutic strategy to control HNSCC.
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Affiliation(s)
- Nobuko Iikawa
- Department of Molecular and Tumour Pathology, Akita University Graduate School of Medicine, Akita 010-8543, Japan.
- Department of Otorhinolaryngology and Head-and-Neck Surgery, Akita University Graduate School of Medicine, Akita 010-8543, Japan.
| | - Yohei Yamamoto
- Department of Molecular and Tumour Pathology, Akita University Graduate School of Medicine, Akita 010-8543, Japan.
| | - Yohei Kawasaki
- Department of Otorhinolaryngology and Head-and-Neck Surgery, Akita University Graduate School of Medicine, Akita 010-8543, Japan.
| | - Aki Nishijima-Matsunobu
- Department of Molecular and Tumour Pathology, Akita University Graduate School of Medicine, Akita 010-8543, Japan.
| | - Maya Suzuki
- Department of Molecular and Tumour Pathology, Akita University Graduate School of Medicine, Akita 010-8543, Japan.
| | - Takechiyo Yamada
- Department of Otorhinolaryngology and Head-and-Neck Surgery, Akita University Graduate School of Medicine, Akita 010-8543, Japan.
| | - Yasufumi Omori
- Department of Molecular and Tumour Pathology, Akita University Graduate School of Medicine, Akita 010-8543, Japan.
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Hejmej A, Bilinska B. The effects of flutamide on cell-cell junctions in the testis, epididymis, and prostate. Reprod Toxicol 2018; 81:1-16. [PMID: 29958919 DOI: 10.1016/j.reprotox.2018.06.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 06/15/2018] [Accepted: 06/20/2018] [Indexed: 12/12/2022]
Abstract
In this review, we summarize recent findings on the effect of the anti-androgen flutamide on cell-cell junctions in the male reproductive system. We outline developmental aspects of flutamide action on the testis, epididymis, and prostate, and describe changes in junction protein expression and organization of junctional complexes in the adult boar following prenatal and postnatal exposure. We also discuss findings on the mechanisms by which flutamide induces alterations in cell-cell junctions in reproductive tissues of adult males, with special emphasis on cytoplasmic effects. Based on the results from in vivo and in vitro studies in the rat, we propose that flutamide affects the expression of junction proteins and junction complex structure not only by inhibiting androgen receptor activity, but equally important by modulating protein kinase-dependent signaling in testicular cells. Additionally, results from studies on prostate cancer cell lines point to a role for the cellular molecular outfit in response to flutamide.
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Affiliation(s)
- Anna Hejmej
- Department of Endocrinology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Barbara Bilinska
- Department of Endocrinology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland.
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Ray A, Katoch P, Jain N, Mehta PP. Dileucine-like motifs in the C-terminal tail of connexin32 control its endocytosis and assembly into gap junctions. J Cell Sci 2018; 131:jcs207340. [PMID: 29361528 PMCID: PMC5897717 DOI: 10.1242/jcs.207340] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 01/11/2018] [Indexed: 12/11/2022] Open
Abstract
Defects in assembly of gap junction-forming proteins, called connexins (Cxs), are observed in a variety of cancers. Connexin32 (Cx32; also known as GJB1) is expressed by the polarized cells in epithelia. We discovered two dileucine-based motifs, which govern the intracellular sorting and endocytosis of transmembrane proteins, in the C-terminal tail of Cx32 and explored their role in regulating its endocytosis and gap junction-forming abilities in pancreatic and prostate cancer cells. One motif, designated as LI, was located near the juxtamembrane domain, whereas the other, designated as LL, was located distally. We also discovered a non-canonical motif, designated as LR, in the C-terminal tail. Our results showed that rendering these motifs non-functional had no effect on the intracellular sorting of Cx32. However, rendering the LL or LR motif nonfunctional enhanced the formation of gap junctions by inhibiting Cx32 endocytosis by the clathrin-mediated pathway. Rendering the LI motif nonfunctional inhibited gap junction formation by augmenting the endocytosis of Cx32 via the LL and LR motifs. Our studies have defined distinct roles of these motifs in regulating the endocytosis of Cx32 and its gap junction-forming ability.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Anuttoma Ray
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Parul Katoch
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Nimansha Jain
- Department of Neurology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Parmender P Mehta
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
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15
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Boucher J, Monvoisin A, Vix J, Mesnil M, Thuringer D, Debiais F, Cronier L. Connexins, important players in the dissemination of prostate cancer cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:202-215. [PMID: 28693897 DOI: 10.1016/j.bbamem.2017.06.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 06/22/2017] [Accepted: 06/29/2017] [Indexed: 12/25/2022]
Abstract
Over the past 50years, increasing experimental evidences have established that connexins (Cxs) and gap junctional intercellular communication (GJIC) ensure an important role in both the onset and development of cancerous processes. In the present review, we focus on the impact of Cxs and GJIC during the development of prostate cancer (PCa), from the primary growth mainly localized in acinar glands and ducts to the distant metastasis mainly concentrated in bone. As observed in several other types of solid tumours, Cxs and especially Cx43 exhibit an ambivalent role with a tumour suppressor effect in the early stages and, conversely, a rather pro-tumoural profile for most of invasion and dissemination steps to secondary sites. We report here the current knowledge on the function of Cxs during PCa cells migration, cytoskeletal dynamics, proteinases activities and the cross talk with the surrounding stromal cells in the microenvironment of the tumour and the bones. In addition, we discuss the role of Cxs in the bone tropism even if the prostate model is rarely used to study the complete sequence of cancer dissemination compared to breast cancer or melanoma. Even if not yet fully understood, these recent findings on Cxs provide new insights into their molecular mechanisms associated with progression and bone targeted behaviour of PCa. This article is part of a Special Issue entitled: Gap Junction Proteins edited by Jean Claude Herve.
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Affiliation(s)
- Jonathan Boucher
- Laboratory Signalisation et Transports Ioniques Membranaires (STIM), ERL7368 - CNRS, University of Poitiers, Poitiers, France
| | - Arnaud Monvoisin
- Laboratory Signalisation et Transports Ioniques Membranaires (STIM), ERL7368 - CNRS, University of Poitiers, Poitiers, France
| | - Justine Vix
- Laboratory Signalisation et Transports Ioniques Membranaires (STIM), ERL7368 - CNRS, University of Poitiers, Poitiers, France; Department of Rheumatology, C.H.U. la Milétrie, Poitiers, France
| | - Marc Mesnil
- Laboratory Signalisation et Transports Ioniques Membranaires (STIM), ERL7368 - CNRS, University of Poitiers, Poitiers, France
| | | | - Françoise Debiais
- Laboratory Signalisation et Transports Ioniques Membranaires (STIM), ERL7368 - CNRS, University of Poitiers, Poitiers, France; Department of Rheumatology, C.H.U. la Milétrie, Poitiers, France
| | - Laurent Cronier
- Laboratory Signalisation et Transports Ioniques Membranaires (STIM), ERL7368 - CNRS, University of Poitiers, Poitiers, France.
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16
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Liu Q, Ji X, Ge Z, Diao H, Chang X, Wang L, Wu Q. Role of connexin 43 in cadmium-induced proliferation of human prostate epithelial cells. J Appl Toxicol 2017; 37:933-942. [PMID: 28176351 DOI: 10.1002/jat.3441] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 12/21/2016] [Accepted: 12/23/2016] [Indexed: 12/21/2022]
Abstract
Connexins (Cxs), the subunits of gap junction channels, are involved in many physiological processes. Aberrant control of Cxs and gap junction intercellular communication may contribute to many diseases, including the promotion of cancer. Cd exposure is associated with increased risk of human prostate cancer and benign prostatic hyperplasia. The roles of Cxs in the effects of Cd on the prostate have, however, not been reported previously. In this study, the human prostate epithelial cell line RWPE-1 was exposed to Cd. A low dose of Cd stimulated cell proliferation along with a lower degree of gap junction intercellular communication and an elevated level of the protein Cx43. Cd exposure increased the levels of intracellular Ca2+ and phosphorylated Cx43 at the Ser368 site. Knockdown of Cx43 using siRNA blocked Cd-induced proliferation and interfered with the Cd-induced changes in the protein levels of cyclin D1, cyclin B1, p27Kip1 (p27) and p21Waf1/Cip1 (p21). The increase in Cx43 expression induced by Cd was presumably mediated by the androgen receptor, because it was abolished upon treatment with the androgen receptor antagonist, flutamide. Thus, a low dose of Cd promotes cell proliferation in RWPE-1, possibly mediated by Cx43 expression through an effect on cell cycle-associated proteins. Cx43 might be a target for prostatic diseases associated with Cd exposure. Copyright © 2017 John Wiley & Sons, Ltd.
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Affiliation(s)
- Qingping Liu
- School of Public Health, Fudan University, DongAn Road, Shanghai, 200032, China.,Key Laboratory of Public Health Safety, Ministry of Education, DongAn Road, Shanghai, 200032, China
| | - Xiaoli Ji
- School of Public Health, Fudan University, DongAn Road, Shanghai, 200032, China.,Key Laboratory of Public Health Safety, Ministry of Education, DongAn Road, Shanghai, 200032, China
| | - Zehe Ge
- School of Public Health, Fudan University, DongAn Road, Shanghai, 200032, China.,Key Laboratory of Public Health Safety, Ministry of Education, DongAn Road, Shanghai, 200032, China
| | - Haipeng Diao
- School of Public Health, Fudan University, DongAn Road, Shanghai, 200032, China.,Key Laboratory of Public Health Safety, Ministry of Education, DongAn Road, Shanghai, 200032, China
| | - Xiuli Chang
- School of Public Health, Fudan University, DongAn Road, Shanghai, 200032, China.,Key Laboratory of Public Health Safety, Ministry of Education, DongAn Road, Shanghai, 200032, China
| | - Lihua Wang
- Shanghai Jinshan District Center for Disease Control & Prevention, Weisheng Road, Jinshan District, Shanghai, 201599, China
| | - Qing Wu
- School of Public Health, Fudan University, DongAn Road, Shanghai, 200032, China.,Key Laboratory of Public Health Safety, Ministry of Education, DongAn Road, Shanghai, 200032, China
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17
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Abstract
Fifty years ago, tumour cells were found to lack electrical coupling, leading to the hypothesis that loss of direct intercellular communication is commonly associated with cancer onset and progression. Subsequent studies linked this phenomenon to gap junctions composed of connexin proteins. Although many studies support the notion that connexins are tumour suppressors, recent evidence suggests that, in some tumour types, they may facilitate specific stages of tumour progression through both junctional and non-junctional signalling pathways. This Timeline article highlights the milestones connecting gap junctions to cancer, and underscores important unanswered questions, controversies and therapeutic opportunities in the field.
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Affiliation(s)
- Trond Aasen
- (Co-corresponding authors) Correspondence to
T.A. () and D.W.L.
()
| | - Marc Mesnil
- STIM Laboratory ERL 7368 CNRS - Faculté des Sciences
Fondamentales et Appliquées, Université de Poitiers, Poitiers,
France
| | - Christian C. Naus
- Department of Cellular and Physiological Sciences, The Life
Sciences Institute, University of British Columbia, Vancouver, British
Columbia, Canada
| | - Paul D. Lampe
- Translational Research Program, Fred Hutchinson Cancer Research
Center, Seattle, United States
| | - Dale W. Laird
- (Co-corresponding authors) Correspondence to
T.A. () and D.W.L.
()
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18
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Leithe E. Regulation of connexins by the ubiquitin system: Implications for intercellular communication and cancer. Biochim Biophys Acta Rev Cancer 2016; 1865:133-46. [DOI: 10.1016/j.bbcan.2016.02.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 01/15/2016] [Accepted: 02/04/2016] [Indexed: 12/31/2022]
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19
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Interaction of Cx43 with Hsc70 regulates G1/S transition through CDK inhibitor p27. Sci Rep 2015; 5:15365. [PMID: 26481195 PMCID: PMC4612729 DOI: 10.1038/srep15365] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 09/22/2015] [Indexed: 01/26/2023] Open
Abstract
Connexin 43 (Cx43) functions as a cell growth suppressor. We have demonstrated that Cx43 interacts with heat shock cognate protein 70 (Hsc70) for regulating cell proliferation. Hsc70 interacts with CDK inhibitor p27, which regulates the assembly and subcellular localization of cyclin D1-CDK4-p27 complex. However, the involvement of p27 with Cx43-mediated cell cycle suppression is still poorly understood. Here, we report that nuclear accumulation of p27 is reduced by overexpression of Cx43, and that this reduction is restored by co-overexpression with Hsc70. We found that Cx43 competes with p27 for binding to Hsc70, and as a result, decreases the level of Hsc70 in cyclin D1-CDK4-p27 complex, leading to prevention of the nuclear translocation of the complex and the G1/S transition. Collectively, our findings suggest that, in Cx43 up-regulation, which is most likely an emergency measure, Cx43-Hsc70 interaction regulates cell cycle G1/S progression through a novel mechanism by which Cx43-Hsc70 interaction prevents the nuclear accumulation of p27 through controlling the nuclear translocation of cyclin D1-CDK4-p27 complex.
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20
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Liu Y, Wen Q, Chen XL, Yang SJ, Gao L, Gao L, Zhang C, Li JL, Xiang XX, Wan K, Chen XH, Zhang X, Zhong JF. All-trans retinoic acid arrests cell cycle in leukemic bone marrow stromal cells by increasing intercellular communication through connexin 43-mediated gap junction. J Hematol Oncol 2015; 8:110. [PMID: 26446715 PMCID: PMC4597383 DOI: 10.1186/s13045-015-0212-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 09/28/2015] [Indexed: 01/28/2023] Open
Abstract
Background Gap junctional intercellular communication (GJIC) is typically decreased in malignant tumors. Gap junction is not presented between hematopoietic cells but occurred in bone marrow stromal cells (BMSCs). Connexin 43 (Cx43) is the major gap junction (GJ) protein; our previous study revealed that Cx43 expression and GJIC were decreased in acute leukemic BMSCs. All-trans retinoic acid (ATRA) increases GJIC in a variety of cancer cells and has been used to treat acute promyelocytic leukemia, but the effects of ATRA on leukemic BMSCs is unknown. In this study, we evaluated the potential effects of ATRA on cell cycle, proliferation, and apoptosis of leukemic BMSCs. Effects of ATRA on Cx43 expression and GJIC were also examined. Methods Human BMSCs obtained from 25 patients with primary acute leukemia, and 10 normal healthy donors were cultured. Effects of ATRA on cell cycle, cell proliferation, and apoptosis were examined with or without co-treatment with amphotericin-B. Cx43 expression was examined at both the mRNA and protein expression levels. GJIC was examined by using a dye transfer assay and measuring the rate of fluorescence recovery after photobleaching (FRAP). Results ATRA arrested the cell cycle progression, inhibited cell growth, and increased apoptosis in leukemic BMSCs. Both Cx43 expression and GJIC function were increased by ATRA treatment. Most of the observed effects mediated by ATRA were abolished by amphotericin-B pretreatment. Conclusions ATRA arrests cell cycle progression in leukemic BMSCs, likely due to upregulating Cx43 expression and enhancing GJIC function. Electronic supplementary material The online version of this article (doi:10.1186/s13045-015-0212-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yao Liu
- Department of Hematology, Xinqiao Hospital, the Third Military Medical University, Xinqiao Street, Chongqing, 400037, China. .,Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA.
| | - Qin Wen
- Department of Hematology, Xinqiao Hospital, the Third Military Medical University, Xinqiao Street, Chongqing, 400037, China.
| | - Xue-Lian Chen
- Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA.
| | - Shi-Jie Yang
- Department of Hematology, Xinqiao Hospital, the Third Military Medical University, Xinqiao Street, Chongqing, 400037, China.
| | - Lei Gao
- Department of Hematology, Xinqiao Hospital, the Third Military Medical University, Xinqiao Street, Chongqing, 400037, China.
| | - Li Gao
- Department of Hematology, Xinqiao Hospital, the Third Military Medical University, Xinqiao Street, Chongqing, 400037, China.
| | - Cheng Zhang
- Department of Hematology, Xinqiao Hospital, the Third Military Medical University, Xinqiao Street, Chongqing, 400037, China.
| | - Jia-Li Li
- Department of Hematology, Xinqiao Hospital, the Third Military Medical University, Xinqiao Street, Chongqing, 400037, China.
| | - Xi-Xi Xiang
- Department of Hematology, Xinqiao Hospital, the Third Military Medical University, Xinqiao Street, Chongqing, 400037, China.
| | - Kai Wan
- Department of Hematology, Xinqiao Hospital, the Third Military Medical University, Xinqiao Street, Chongqing, 400037, China.
| | - Xing-Hua Chen
- Department of Hematology, Xinqiao Hospital, the Third Military Medical University, Xinqiao Street, Chongqing, 400037, China.
| | - Xi Zhang
- Department of Hematology, Xinqiao Hospital, the Third Military Medical University, Xinqiao Street, Chongqing, 400037, China.
| | - Jiang-Fan Zhong
- Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA.
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21
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Thuringer D, Berthenet K, Cronier L, Solary E, Garrido C. Primary tumor- and metastasis-derived colon cancer cells differently modulate connexin expression and function in human capillary endothelial cells. Oncotarget 2015; 6:28800-15. [PMID: 26320187 PMCID: PMC4745693 DOI: 10.18632/oncotarget.4894] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 07/24/2015] [Indexed: 12/30/2022] Open
Abstract
A gradual loss of functional gap junction between tumor cells has been reported with colorectal cancer (CRC) progression. Here, we explored if colon cancer cells could also affect gap junctions in blood capillary cells. Human microvascular endothelial cells (HMEC) were cultured with two CRC cell lines established from a unique patient. SW480 cells, derived from the primary tumor, migrate much faster across HMEC monolayer than SW620 cells derived from a metastatic site. The motile SW480 cells highly express and release HSP27 that increases gap junction formation with HMEC. Soluble HSP27 phosphorylates the connexin Cx43 on serine residues and induces its interaction with the oncoprotein 14-3-3, which promotes Cx43 delivery at the plasma membrane. The factors secreted by less motile SW620 cells do not affect Cx43 expression but up-regulate the expression of the connexin Cx32 through an activation of the chemokine receptor CXCR2. In turn, SW620 secreted factors induce tubulogenesis and ATP release. Altogether, cell lines derived from CRC primary tumor and metastasis differentially adapt endothelial cell functions by modulating connexin expression through released mediators.
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Affiliation(s)
| | | | - Laurent Cronier
- CNRS ERL7368, STIM Lab, University of Poitiers, 86022 Poitiers, France
| | - Eric Solary
- INSERM, U1170, Institut Gustave Roussy, 94508 Villejuif, France
| | - Carmen Garrido
- INSERM, U866 Faculty of Medecine, 21000 Dijon, France
- University of Bourgogne-Franche-Comté, 21000 Dijon, France
- CGFL, 21000 Dijon, France
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22
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Kibschull M, Gellhaus A, Carette D, Segretain D, Pointis G, Gilleron J. Physiological roles of connexins and pannexins in reproductive organs. Cell Mol Life Sci 2015; 72:2879-98. [PMID: 26100514 PMCID: PMC11114083 DOI: 10.1007/s00018-015-1965-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 06/11/2015] [Indexed: 12/15/2022]
Abstract
Reproductive organs are complex and well-structured tissues essential to perpetuate the species. In mammals, the male and female reproductive organs vary on their organization, morphology and function. Connectivity between cells in such tissues plays pivotal roles in organogenesis and tissue functions through the regulation of cellular proliferation, migration, differentiation and apoptosis. Connexins and pannexins can be seen as major regulators of these physiological processes. In the present review, we assembled several lines of evidence demonstrating that these two families of proteins are essential for male and female reproduction.
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Affiliation(s)
- Mark Kibschull
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 25 Orde Street, Toronto, M5T 3H7 Canada
| | - Alexandra Gellhaus
- Department of Gynecology and Obstetrics, University of Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany
| | - Diane Carette
- UMR S1147, University Paris Descartes, 45 rue des Saints-Pères, 75006 Paris, France
- University of Versailles, 78035 Saint Quentin, France
- INSERM U 1065, University of Nice Sophia-Antipolis, 151 Route Saint-Antoine de Ginestière, BP 2 3194, 06204 Nice Cedex 3, France
| | - Dominique Segretain
- UMR S1147, University Paris Descartes, 45 rue des Saints-Pères, 75006 Paris, France
- University of Versailles, 78035 Saint Quentin, France
| | - Georges Pointis
- INSERM U 1065, University of Nice Sophia-Antipolis, 151 Route Saint-Antoine de Ginestière, BP 2 3194, 06204 Nice Cedex 3, France
| | - Jerome Gilleron
- INSERM U 1065, University of Nice Sophia-Antipolis, 151 Route Saint-Antoine de Ginestière, BP 2 3194, 06204 Nice Cedex 3, France
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23
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Gap Junction-associated Na+ Influx Is Involved in the Mediation of Ca2+ Transients in Neonatal Rat Ventricular Myocytes. J Cardiovasc Pharmacol 2015; 66:41-9. [DOI: 10.1097/fjc.0000000000000241] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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24
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Katoch P, Mitra S, Ray A, Kelsey L, Roberts BJ, Wahl JK, Johnson KR, Mehta PP. The carboxyl tail of connexin32 regulates gap junction assembly in human prostate and pancreatic cancer cells. J Biol Chem 2015; 290:4647-4662. [PMID: 25548281 PMCID: PMC4335205 DOI: 10.1074/jbc.m114.586057] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 12/23/2014] [Indexed: 12/20/2022] Open
Abstract
Connexins, the constituent proteins of gap junctions, are transmembrane proteins. A connexin (Cx) traverses the membrane four times and has one intracellular and two extracellular loops with the amino and carboxyl termini facing the cytoplasm. The transmembrane and the extracellular loop domains are highly conserved among different Cxs, whereas the carboxyl termini, often called the cytoplasmic tails, are highly divergent. We have explored the role of the cytoplasmic tail of Cx32, a Cx expressed in polarized and differentiated cells, in regulating gap junction assembly. Our results demonstrate that compared with the full-length Cx32, the cytoplasmic tail-deleted Cx32 is assembled into small gap junctions in human pancreatic and prostatic cancer cells. Our results further document that the expression of the full-length Cx32 in cells, which express the tail-deleted Cx32, increases the size of gap junctions, whereas the expression of the tail-deleted Cx32 in cells, which express the full-length Cx32, has the opposite effect. Moreover, we show that the tail is required for the clustering of cell-cell channels and that in cells expressing the tail-deleted Cx32, the expression of cell surface-targeted cytoplasmic tail alone is sufficient to enhance the size of gap junctions. Our live-cell imaging data further demonstrate that gap junctions formed of the tail-deleted Cx32 are highly mobile compared with those formed of full-length Cx32. Our results suggest that the cytoplasmic tail of Cx32 is not required to initiate the assembly of gap junctions but for their subsequent growth and stability. Our findings suggest that the cytoplasmic tail of Cx32 may be involved in regulating the permeability of gap junctions by regulating their size.
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Affiliation(s)
- Parul Katoch
- From the Department of Biochemistry and Molecular Biology, Department of Oral Biology, Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Shalini Mitra
- From the Department of Biochemistry and Molecular Biology, Department of Oral Biology, Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Anuttoma Ray
- From the Department of Biochemistry and Molecular Biology, Department of Oral Biology, Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Linda Kelsey
- From the Department of Biochemistry and Molecular Biology, Department of Oral Biology, Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Brett J Roberts
- From the Department of Biochemistry and Molecular Biology, Department of Oral Biology, Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - James K Wahl
- From the Department of Biochemistry and Molecular Biology, Department of Oral Biology, Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Keith R Johnson
- From the Department of Biochemistry and Molecular Biology, Department of Oral Biology, Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Parmender P Mehta
- From the Department of Biochemistry and Molecular Biology, Department of Oral Biology, Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198.
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25
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Aasen T. Connexins: junctional and non-junctional modulators of proliferation. Cell Tissue Res 2014; 360:685-99. [PMID: 25547217 DOI: 10.1007/s00441-014-2078-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2014] [Accepted: 11/14/2014] [Indexed: 12/11/2022]
Abstract
Mounting evidence indicates that dysregulation of gap junctions and their structural subunits-connexins-often occurs in, and sometimes causes, a variety of proliferative disorders, including cancer. Connexin-mediated regulation of cell proliferation is complex and may involve modulation of gap junction intercellular communication (GJIC), hemichannel signalling, or gap junction-independent paths. However, the exact mechanisms linking connexins to proliferation remain poorly defined and a number of contradictory studies report both pro- and anti-proliferative effects, effects that often depend on the cell or tissue type or the microenvironment. The present review covers junctional and non-junctional regulation of proliferation by connexins, with a particular emphasis on their association with cancer.
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Affiliation(s)
- Trond Aasen
- Molecular Pathology Group, Vall d'Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Passeig Vall d'Hebron 119-129, Barcelona, 08035, Spain,
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26
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Kelsey L, Katoch P, Ray A, Mitra S, Chakraborty S, Lin MF, Mehta PP. Vitamin D3 regulates the formation and degradation of gap junctions in androgen-responsive human prostate cancer cells. PLoS One 2014; 9:e106437. [PMID: 25188420 PMCID: PMC4154685 DOI: 10.1371/journal.pone.0106437] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 08/06/2014] [Indexed: 11/19/2022] Open
Abstract
1α-25(OH)2 vitamin D3 (1-25D), an active hormonal form of Vitamin D3, is a well-known chemopreventive and pro-differentiating agent. It has been shown to inhibit the growth of several prostate cancer cell lines. Gap junctions, formed of proteins called connexins (Cx), are ensembles of cell-cell channels, which permit the exchange of small growth regulatory molecules between adjoining cells. Cell-cell communication mediated by gap junctional channels is an important homeostatic control mechanism for regulating cell growth and differentiation. We have investigated the effect of 1-25D on the formation and degradation of gap junctions in an androgen-responsive prostate cancer cell line, LNCaP, which expresses retrovirally-introduced Cx32. Connexin32 is expressed by the luminal and well-differentiated cells of normal prostate and prostate tumors. Our results document that 1-25D enhances the expression of Cx32 and its subsequent assembly into gap junctions. Our results further show that 1-25D prevents androgen-regulated degradation of Cx32, post-translationally, independent of androgen receptor (AR)-mediated signaling. Finally, our findings document that formation of gap junctions sensitizes Cx32-expressing LNCaP cells to the growth inhibitory effects of 1-25D and alters their morphology. These findings suggest that the growth-inhibitory effects of 1-25D in LNCaP cells may be related to its ability to modulate the assembly of Cx32 into gap junctions.
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Affiliation(s)
- Linda Kelsey
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Parul Katoch
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Anuttoma Ray
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Shalini Mitra
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Souvik Chakraborty
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Ming-Fong Lin
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Parmender P. Mehta
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
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Sirnes S, Lind GE, Bruun J, Fykerud TA, Mesnil M, Lothe RA, Rivedal E, Kolberg M, Leithe E. Connexins in colorectal cancer pathogenesis. Int J Cancer 2014; 137:1-11. [PMID: 24752574 DOI: 10.1002/ijc.28911] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 03/11/2014] [Indexed: 12/17/2022]
Abstract
The connexins constitute a family of integral membrane proteins that form channels between adjacent cells. These channels are assembled in plasma membrane domains known as gap junctions and enable cells to directly exchange ions and small molecules. Intercellular communication via gap junctions plays important roles in regulating cell growth and differentiation and in maintaining tissue homeostasis. This type of cell communication is often impaired during cancer development, and several members of the connexin protein family have been shown to act as tumor suppressors. Emerging evidence suggests that the connexin protein family has important roles in colorectal cancer development. In the normal colonic epithelial tissue, three connexin isoforms, connexin 26 (Cx26), Cx32 and Cx43, have been shown to be expressed at the protein level. Colorectal cancer development is associated with loss of connexin expression or relocalization of connexins from the plasma membrane to intracellular compartments. Downregulation of connexins in colorectal carcinomas at the transcriptional level involves cancer-specific promoter hypermethylation. Recent studies suggest that Cx43 may constrain growth of colon cancer cells by interfering with the Wnt/β-catenin pathway. There is also increasing evidence that the connexins may have potential as prognostic markers in colorectal cancer. This review discusses the role of connexins in colorectal cancer pathogenesis, as well as their potential as prognostic markers and targets in the prevention and treatment of the disease.
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Affiliation(s)
- Solveig Sirnes
- Department of Cancer Prevention, Institute for Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway; Faculty of Medicine, Centre for Cancer Biomedicine, University of Oslo, Oslo, Norway
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Connexin43 functions as a novel interacting partner of heat shock cognate protein 70. Sci Rep 2014; 3:2719. [PMID: 24056538 PMCID: PMC3779846 DOI: 10.1038/srep02719] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 09/04/2013] [Indexed: 01/12/2023] Open
Abstract
Regulation of connexin43 (Cx43) expression affects cell proliferation, differentiation and apoptosis in a gap junctional intercellular communication (GJIC)-independent manner. However, the underlying mechanisms of Cx43-mediated cell cycle suppression are still poorly understood. To elucidate the molecular mechanism of Cx43-mediated cell cycle suppression, we searched for Cx43 interacting proteins by using a proteomics approach. Here, we have identified a Cx43-interacting protein, heat shock cognate protein 70 (Hsc70). We confirmed that Hsc70 directly binds to the C-terminus of Cx43, whereas Hsc54, a splice variant of Hsc70, does not, that Cx43 competes with cyclin D1 for binding to Hsc70, and that the nuclear accumulation of cyclin D1 is reduced by overexpression of Cx43 in a GJIC-independent manner, which is restored by co-overexpression with Hsc70. As a result, the cell proliferation is regulated by Cx43. Our results suggest that Cx43-Hsc70 interaction probably plays a critical role during G1/S progression.
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Lee KH. Differential Expression of Multiple Connexins in Rat Corpus and Cauda Epididymis at Various Postnatal Stages. JOURNAL OF ANIMAL SCIENCE AND TECHNOLOGY 2013. [DOI: 10.5187/jast.2013.55.6.521] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Nielsen MS, Axelsen LN, Sorgen PL, Verma V, Delmar M, Holstein-Rathlou NH. Gap junctions. Compr Physiol 2013; 2:1981-2035. [PMID: 23723031 DOI: 10.1002/cphy.c110051] [Citation(s) in RCA: 289] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Gap junctions are essential to the function of multicellular animals, which require a high degree of coordination between cells. In vertebrates, gap junctions comprise connexins and currently 21 connexins are known in humans. The functions of gap junctions are highly diverse and include exchange of metabolites and electrical signals between cells, as well as functions, which are apparently unrelated to intercellular communication. Given the diversity of gap junction physiology, regulation of gap junction activity is complex. The structure of the various connexins is known to some extent; and structural rearrangements and intramolecular interactions are important for regulation of channel function. Intercellular coupling is further regulated by the number and activity of channels present in gap junctional plaques. The number of connexins in cell-cell channels is regulated by controlling transcription, translation, trafficking, and degradation; and all of these processes are under strict control. Once in the membrane, channel activity is determined by the conductive properties of the connexin involved, which can be regulated by voltage and chemical gating, as well as a large number of posttranslational modifications. The aim of the present article is to review our current knowledge on the structure, regulation, function, and pharmacology of gap junctions. This will be supported by examples of how different connexins and their regulation act in concert to achieve appropriate physiological control, and how disturbances of connexin function can lead to disease.
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Affiliation(s)
- Morten Schak Nielsen
- Department of Biomedical Sciences and The Danish National Research Foundation Centre for Cardiac Arrhythmia, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
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Chandrasekhar A, Kalmykov EA, Polusani SR, Mathis SA, Zucker SN, Nicholson BJ. Intercellular redistribution of cAMP underlies selective suppression of cancer cell growth by connexin26. PLoS One 2013; 8:e82335. [PMID: 24312655 PMCID: PMC3849486 DOI: 10.1371/journal.pone.0082335] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 10/30/2013] [Indexed: 12/02/2022] Open
Abstract
Connexins (Cx), which constitute gap junction intercellular channels in vertebrates, have been shown to suppress transformed cell growth and tumorigenesis, but the mechanism(s) still remain largely speculative. Here, we define the molecular basis by which Cx26, but less frequently Cx43 or Cx32, selectively confer growth suppression on cancer cells. Functional intercellular coupling is shown to be required, producing partial blocks of the cell cycle due to prolonged activation of several mitogenic kinases. PKA is both necessary and sufficient for the Cx26 induced growth inhibition in low serum and the absence of anchorage. Activation of PKA was not associated with elevated cAMP levels, but appeared to result from a redistribution of cAMP throughout the cell population, eliminating the cell cycle oscillations in cAMP required for efficient cell cycle progression. Cx43 and Cx32 fail to mediate this redistribution as, unlike Cx26, these channels are closed during the G2/M phase of the cell cycle when cAMP levels peak. Comparisons of tumor cell lines indicate that this is a general pattern, with growth suppression by connexins occurring whenever cAMP oscillates with the cell cycle, and the gap junction remain open throughout the cell cycle. Thus, gap junctional coupling, in the absence of any external signals, provides a general means to limit the mitotic rate of cell populations.
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Affiliation(s)
- Anjana Chandrasekhar
- Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Edward A. Kalmykov
- Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Srikanth R. Polusani
- Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Sandra A. Mathis
- Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Shoshanna N. Zucker
- Department of Pharmaceutical, Social and Administrative Sciences, D'Youville College School of Pharmacy,Buffalo, New York, United States of America
| | - Bruce J. Nicholson
- Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
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Androgen signaling disruption during fetal and postnatal development affects androgen receptor and connexin 43 expression and distribution in adult boar prostate. BIOMED RESEARCH INTERNATIONAL 2013; 2013:407678. [PMID: 24151599 PMCID: PMC3789303 DOI: 10.1155/2013/407678] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 07/29/2013] [Accepted: 08/07/2013] [Indexed: 12/05/2022]
Abstract
To date, limited knowledge exists regarding the role of the androgen signaling during specific periods of development in the regulation of androgen receptor (AR) and connexin 43 (Cx43) in adult prostate. Therefore, in this study we examined mRNA and protein expression, and tissue distribution of AR and Cx43 in adult boar prostates following fetal (GD20), neonatal (PD2), and prepubertal (PD90) exposure to an antiandrogen flutamide (50 mg/kg bw). In GD20 and PD2 males we found the reduction of the luminal compartment, inflammatory changes, decreased AR and increased Cx43 expression, and altered localization of both proteins. Moreover, enhanced apoptosis and reduced proliferation were detected in the prostates of these animals. In PD90 males the alterations were less evident, except that Cx43 expression was markedly upregulated. The results presented herein indicate that in boar androgen action during early fetal and neonatal periods plays a key role in the maintenance of normal phenotype and functions of prostatic cells at adulthood. Furthermore, we demonstrated that modulation of Cx43 expression in the prostate could serve as a sensitive marker of hormonal disruption during different developmental stages.
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Six-transmembrane epithelial antigen of the prostate-1 plays a role for in vivo tumor growth via intercellular communication. Exp Cell Res 2013; 319:2617-26. [PMID: 23916873 DOI: 10.1016/j.yexcr.2013.07.025] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2013] [Revised: 07/05/2013] [Accepted: 07/26/2013] [Indexed: 11/22/2022]
Abstract
Six-transmembrane epithelial antigen of the prostate-1 (STEAP-1) is a novel cell surface protein overexpressed only in the prostate among normal tissues and various types of cancer including prostate, bladder, lung, and ovarian cancer. Although its function in prostate and tumor cells has been remained unclear, due to its unique and restricted expression, STEAP-1 is expected to be an attractive target for cancer therapy. Here, we show that knockdown of STEAP-1 in human cancer cells caused the retardation of tumor growth compared with wild type in vivo. In contrast, STEAP-1 introduced tumor cells augmented the tumor growth compared with STEAP-1-negative wild type cells. Using dye transfer assay, we demonstrate that the STEAP-1 is involved in intercellular communication between tumor cells and adjacent tumor stromal cells and therefore may play a key role for the tumor growth in vivo. These data indicate the inhibition of the STEAP-1 function or expression can be a new strategy for cancer therapy.
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Mechanisms of prostate permeability triggered by microbubble-mediated acoustic cavitation. Cell Biochem Biophys 2013; 64:147-53. [PMID: 22722876 DOI: 10.1007/s12013-012-9383-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The objective of this research was to study the mechanisms of opening of the blood-prostate barrier and increased permeability of prostate tissue induced by microbubble cavitation. Thirty-five rabbits were randomly divided into four study groups: (1) control group and groups exposed to (2) microbubble alone, (3) ultrasound alone, or (4) combined intervention (ultrasound + microbubble group). Evans blue (EB) tracer was used to gauge the changes of permeability of prostate tissue. Furthermore, light and electron microscopy analyses were conducted, as well as the western blot analysis of expression of gap junction (Cx43) protein. We observed that EB concentration in prostate tissue was significantly greater in the ultrasound + microbubble group compared with either intervention alone (p < 0.05, both comparisons). Furthermore, light microscopy of tissue samples from animals exposed to ultrasound + microbubble showed epithelial cell disarrangement, loss of interstitial structure, and thickness of fibrous stroma. In line with these findings, electron microscopy analysis demonstrated widening of cell gaps and broken cell connections, as well as more dense lysosomes and secretary granules, and mitochondrial swelling. These changes were absent in the animals exposed to microbubble or ultrasound alone. Finally, only combined treatment with microbubble or ultrasound significantly elevated expression of Cx43 (p < 0.05 vs. control group). In conclusion, increases of permeability of prostate tissue by acoustic cavitation appear to involve opening of tight junctions, widening of intracellular spaces, changes in the structure of acinar cell membrane, enhancement of vesicular transport, and loosening of fibrous stroma. Increased expression of cell gap junction protein will help to restore normal connections between cells and the blood-prostate barrier after the treatment.
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Johnson KE, Mitra S, Katoch P, Kelsey LS, Johnson KR, Mehta PP. Phosphorylation on Ser-279 and Ser-282 of connexin43 regulates endocytosis and gap junction assembly in pancreatic cancer cells. Mol Biol Cell 2013; 24:715-33. [PMID: 23363606 PMCID: PMC3596244 DOI: 10.1091/mbc.e12-07-0537] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The molecular mechanisms regulating the assembly of connexins (Cxs) into gap junctions are poorly understood. Using human pancreatic tumor cell lines BxPC3 and Capan-1, which express Cx26 and Cx43, we show that, upon arrival at the cell surface, the assembly of Cx43 is impaired. Connexin43 fails to assemble, because it is internalized by clathrin-mediated endocytosis. Assembly is restored upon expressing a sorting-motif mutant of Cx43, which does not interact with the AP2 complex, and by expressing mutants that cannot be phosphorylated on Ser-279 and Ser-282. The mutants restore assembly by preventing clathrin-mediated endocytosis of Cx43. Our results also document that the sorting-motif mutant is assembled into gap junctions in cells in which the expression of endogenous Cx43 has been knocked down. Remarkably, Cx43 mutants that cannot be phosphorylated on Ser-279 or Ser-282 are assembled into gap junctions only when connexons are composed of Cx43 forms that can be phosphorylated on these serines and forms in which phosphorylation on these serines is abolished. Based on the subcellular fate of Cx43 in single and contacting cells, our results document that the endocytic itinerary of Cx43 is altered upon cell-cell contact, which causes Cx43 to traffic by EEA1-negative endosomes en route to lysosomes. Our results further show that gap-junctional plaques formed of a sorting motif-deficient mutant of Cx43, which is unable to be internalized by the clathrin-mediated pathway, are predominantly endocytosed in the form of annular junctions. Thus the differential phosphorylation of Cx43 on Ser-279 and Ser-282 is fine-tuned to control Cx43's endocytosis and assembly into gap junctions.
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Affiliation(s)
- Kristen E Johnson
- Department of Biochemistry and Molecular Biology, Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA
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36
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Bijnsdorp IV, Rozendaal L, van Moorselaar RJA, Geldof AA. A predictive role for noncancerous prostate cells: low connexin-26 expression in radical prostatectomy tissues predicts metastasis. Br J Cancer 2012; 107:1963-8. [PMID: 23169284 PMCID: PMC3516687 DOI: 10.1038/bjc.2012.500] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Background: It is important to identify markers that predict whether prostate cancer will metastasise. The adjacent noncancerous cells (influenced by the tumour cells) may also express potential markers. The objective of this study was to determine the influence of cancer cells on noncancerous cells and to assess the value of the cell-communication protein connexin-26 (Cx26) as a marker to predict the development of metastasis. Methods: The effect of conditioned medium (CM) from PrCa cells on in vitro noncancerous cell proliferation, migration and invasion and Cx26 expression was determined. Connexin-26 expression was investigated in prostatectomy tissues from 51 PrCa patients by immunohistochemistry and compared with various clinicopathological parameters. Results: Proliferation, migration and invasion of noncancerous cells were influenced by CM from the PrCa cell lines. Importantly, a clear relation was found between low Cx26 expression in the noncancerous tissue in prostatectomy sections and the risk of development of metastasis (P<0.0002). Kaplan–Meier analysis showed a relation between low Cx26 expression in noncancerous tissues and time to biochemical recurrence (P=0.0002). Conclusion: Measuring Cx26 expression in the adjacent noncancerous tissues (rather than cancer tissues) of prostatectomy sections could help to identify high-risk patients who may benefit from adjuvant therapy to decrease the risk of metastasis.
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Affiliation(s)
- I V Bijnsdorp
- Department of Urology, VU University Medical Center, De Boelelaan 1117 4F12, Amsterdam 1081 HV, The Netherlands.
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Gilleron J, Carette D, Chevallier D, Segretain D, Pointis G. Molecular connexin partner remodeling orchestrates connexin traffic: from physiology to pathophysiology. Crit Rev Biochem Mol Biol 2012; 47:407-23. [PMID: 22551357 DOI: 10.3109/10409238.2012.683482] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Connexins, through gap junctional intercellular communication, are known to regulate many physiological functions involved in developmental processes such as cell proliferation, differentiation, migration and apoptosis. Strikingly, alterations of connexin expression and trafficking are often, if not always, associated with human developmental diseases and carcinogenesis. In this respect, disrupted trafficking dynamics and aberrant intracytoplasmic localization of connexins are considered as typical features of functionality failure leading to the pathological state. Recent findings demonstrate that interactions of connexins with numerous protein partners, which take place throughout connexin trafficking, are essential for gap junction formation, membranous stabilization and degradation. In the present study, we give an overview of the physiological molecular machinery and of the specific interactions between connexins and their partners, which are involved in connexin trafficking, and we highlight their changes in pathological situations.
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Affiliation(s)
- Jérôme Gilleron
- INSERM U 1065, University Nice Sophia Antipolis, Team 5, C3M, 151 route Saint-Antoine de Ginestière, France
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Kelsey L, Katoch P, Johnson KE, Batra SK, Mehta PP. Retinoids regulate the formation and degradation of gap junctions in androgen-responsive human prostate cancer cells. PLoS One 2012; 7:e32846. [PMID: 22514600 PMCID: PMC3326013 DOI: 10.1371/journal.pone.0032846] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 01/31/2012] [Indexed: 12/13/2022] Open
Abstract
The retinoids, the natural or synthetic derivatives of Vitamin A (retinol), are essential for the normal development of prostate and have been shown to modulate prostate cancer progression in vivo as well as to modulate growth of several prostate cancer cell lines. 9-cis-retinoic acid and all-trans-retinoic acid are the two most important metabolites of retinol. Gap junctions, formed of proteins called connexins, are ensembles of intercellular channels that permit the exchange of small growth regulatory molecules between adjoining cells. Gap junctional communication is instrumental in the control of cell growth. We examined the effect of 9-cis-retinoic acid and all-trans retinoic acid on the formation and degradation of gap junctions as well as on junctional communication in an androgen-responsive prostate cancer cell line, LNCaP, which expressed retrovirally introduced connexin32, a connexin expressed by the luminal cells and well-differentiated cells of prostate tumors. Our results showed that 9-cis-retinoic acid and all-trans retinoic acid enhanced the assembly of connexin32 into gap junctions. Our results further showed that 9-cis-retinoic acid and all-trans-retinoic acid prevented androgen-regulated degradation of gap junctions, post-translationally, independent of androgen receptor mediated signaling. Finally, our findings showed that formation of gap junctions sensitized connexin32-expressing LNCaP cells to the growth modifying effects of 9-cis-retinoic acid, all-trans-retinoic acid and androgens. Thus, the effects of retinoids and androgens on growth and the formation and degradation of gap junctions and their function might be related to their ability to modulate prostate growth and cancer.
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Affiliation(s)
| | | | | | | | - Parmender P. Mehta
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
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Czyż J, Szpak K, Madeja Z. The role of connexins in prostate cancer promotion and progression. Nat Rev Urol 2012; 9:274-82. [PMID: 22349655 DOI: 10.1038/nrurol.2012.14] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Prostate cancer is a prevalent disease that is characterized by a presumably long latency period and a moderate propensity to metastasize. Although a range of mechanisms have been implicated in prostate carcinogenesis, the factors determining the initiation of metastasis remain obscure. The synchronized function of prostate cells depends on their metabolic and electrical coupling; disturbance of these functions has long been suggested to be integral to prostate carcinogenesis. However, although connexins form intercellular channels involved in gap-junction-mediated intercellular coupling (GJIC), whether these proteins also have GJIC-independent roles in cancer progression and metastasis remains a matter of debate. Some data indicate a correlation between connexin expression and the invasive potential of prostate cancer cells, which points to stage-specific functions of connexins during prostate cancer development. For example, restoration of connexin expression seems to be crucial for the formation of invasive cell subsets within heterogeneous prostate cancer cell populations that have undergone aberrant differentiation. Consequently, the clinical application of therapeutic and prophylactic approaches focused on the modulation of connexin expression in prostate cancer cells should be reconsidered.
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Affiliation(s)
- Jarosław Czyż
- Department of Cell Biology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, ul. Gronostajowa 7, 30-387 Kraków, Poland.
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Abstract
Histone acetyltransferase and histone deacetylase are enzymes responsible for histone acetylation and deacetylation, respectively, in which the histones are acetylated and deacetylated on lysine residues in the N-terminal tail and on the surface of the nucleosome core. These processes are considered the most important epigenetic mechanisms for remodeling the chromatin structure and controlling the gene expression. Histone acetylation is associated with gene activation. Sodium phenylbutyrate is a histone deacetylase inhibitor that has been approved for treatement of urea cycle disorders and is under investigation in cancer, hemoglobinopathies, motor neuron diseases, and cystic fibrosis clinical trials. Due to its characteristics, not only of histone deacetylase inhibitor, but also of ammonia sink and chemical chaperone, the interest towards this molecule is growing worldwide. This review aims to update the current literature, involving the use of sodium phenylbutyrate in experimental studies and clinical trials.
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Affiliation(s)
- Tommaso Iannitti
- Department of Biological and Biomedical Sciences, Glasgow Caledonian University, Glasgow, UK.
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The gap junction protein Cx43 is involved in the bone-targeted metastatic behaviour of human prostate cancer cells. Clin Exp Metastasis 2011; 29:111-22. [PMID: 22080401 DOI: 10.1007/s10585-011-9434-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Accepted: 11/01/2011] [Indexed: 01/20/2023]
Abstract
For decades, cancer was associated with gap-junction defects. However, more recently it appeared that the gap junction proteins (connexins) could be re-expressed and participate to cancer cell dissemination during the late stages of tumor progression. Since primary tumors of prostate cancer (PCa) are known to be connexin deficient, it was interesting to verify whether their bone-targeted metastatic behaviour could be influenced by the re-expression of the connexin type (connexin43) which is originally present in prostate tissue and highly expressed in bone where it participates to the differentiation of osteoblastic cells. Thus, we investigated the effect of the increased Cx43 expression, by retroviral infection, on the metastatic behaviour of two well-characterized cell lines (PC-3 and LNCaP) representing different stages of PCa progression. It appeared that Cx43 differently behaved in those cell lines and induced different phenotypes. In LNCaP, Cx43 was functional, localized at the plasma membrane and its high expression was correlated with a more aggressive phenotype both in vitro and in vivo. In particular, those Cx43-expressing LNCaP cells exhibited a high incidence of osteolytic metastases generated by bone xenografts in mice. Interestingly, LNCaP cells were also able to decrease the proliferation of cocultured osteoblastic cells. In contrast, the increased expression of Cx43 in PC-3 cells led to an unfunctional, cytoplasmic localization of the protein and was correlated with a reduction of proliferation, adhesion and invasion of the cells. In conclusion, the localization and the functionality of Cx43 may govern the ability of PCa cells to metastasize in bones.
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Sirnes S, Bruun J, Kolberg M, Kjenseth A, Lind GE, Svindland A, Brech A, Nesbakken A, Lothe RA, Leithe E, Rivedal E. Connexin43 acts as a colorectal cancer tumor suppressor and predicts disease outcome. Int J Cancer 2011; 131:570-81. [PMID: 21866551 DOI: 10.1002/ijc.26392] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Accepted: 07/12/2011] [Indexed: 12/29/2022]
Abstract
This article is the first to show that loss of connexin43 (Cx43) expression in colorectal tumors is correlated with significantly shorter relapse-free and overall survival. Cx43 was further found to negatively regulate growth of colon cancer cells, in part by enhancing apoptosis. In addition, Cx43 was found to colocalize with β-catenin and reduce Wnt signaling. The study represents the first evidence that Cx43 acts as a colorectal cancer tumor suppressor and that loss of Cx43 expression during colorectal cancer development is associated with reduced patient survival. The study has important implications for the assessment of Cx43 as a prognostic marker and target in colorectal cancer prevention and therapy. Gap junctions consist of intercellular channels that permit direct transfer of ions and small molecules between adjacent cells. The gap junction channel protein Cx43 plays important roles in cell growth control and differentiation and is frequently dysregulated in human cancers. However, the functional importance and clinical relevance of Cx43 in cancer development has remained elusive. Here, we show that Cx43 is downregulated or aberrantly localized in colon cancer cell lines and colorectal carcinomas, which is associated with loss of gap junction intercellular communication. The in situ protein expression of Cx43 was analyzed in colorectal tumors in a cohort of 674 patients and related to established clinicopathological variables and survival. A subgroup of the patients had weak or no expression of Cx43 in tumors. Loss of Cx43 expression was significantly correlated with shorter relapse-free and overall survival. Loss of Cx43 further identified a high-risk subgroup among stage I and stage II patients with reduced relapse-free and overall survival. Ectopic expression of Cx43 in the colon cancer cell line HT29 was associated with reduced growth in monolayer and soft agar cultures and in tumor xenografts. Cx43 was found to colocalize with β-catenin and negatively regulate the Wnt signaling pathway, and expression of Cx43 was associated with increased levels of apoptosis. Altogether, these data indicate that Cx43 is a colorectal cancer tumor suppressor protein that predicts clinical outcome.
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Affiliation(s)
- Solveig Sirnes
- Department of Cancer Prevention, Institute for Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
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43
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Jee H, Nam KT, Kwon HJ, Han SU, Kim DY. Altered expression and localization of connexin32 in human and murine gastric carcinogenesis. Dig Dis Sci 2011; 56:1323-32. [PMID: 21082351 DOI: 10.1007/s10620-010-1467-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Accepted: 10/15/2010] [Indexed: 12/27/2022]
Abstract
BACKGROUND Intercellular communication via gap junctions, composed of protein subunits called connexins (Cxs), plays a key role in controlling cell growth, differentiation and carcinogenesis. Impaired gap junctional intercellular communication has been reported in various cancers and diseases. AIMS We investigated Cx32 expression patterns and semiquantitatively assessed Cx32 expression in cancers and preneoplastic lesions. To determine if cell proliferation is correlated with Cx32 expression, we evaluated Ki67 expression in a gastric cancer mouse model. METHODS In human and mouse, normal stomach and gastric adenocarcinoma tissues were used for immunohistochemical analyses. RESULTS Cx32 was detected at cell-cell (intercellular) contact points in normal cells and exhibited punctate intercellular and intracytoplasmic staining in cancer cells. The frequency of Cx32 loss of expression was significantly higher in human adenocarcinomas than in normal stomach. As tumor cells were less differentiated, Cx32 expression levels and intercellular and intracytoplasmic staining were also significantly lower. The Cx32 expression pattern in the mouse gastric cancer model was similar in several important respects to that of human. In mucous metaplasia of the mouse stomach, Cx32 was mainly expressed in the cytoplasm of epithelial cells. There was also an inverse correlation between Cx32 expression and cell proliferation in mouse tumors. However, there was no difference in the levels of Cx32 mRNA between normal and cancerous tissues. CONCLUSIONS These findings suggest that altered Cx32 expression, a loss of intercellular Cx32 and a gain of intracytoplasmic Cx32 in the form of punctate "dot", plays an important role in the formation of gastric adenocarcinomas.
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Affiliation(s)
- Hyang Jee
- Laboratory of Veterinary Pathology, College of Veterinary Medicine, Seoul National University, 599 Gwanak-ro, Gwanak-gu, Seoul, 151-742, Korea.
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Kawasaki Y, Omori Y, Li Q, Nishikawa Y, Yoshioka T, Yoshida M, Ishikawa K, Enomoto K. Cytoplasmic accumulation of connexin32 expands cancer stem cell population in human HuH7 hepatoma cells by enhancing its self-renewal. Int J Cancer 2011; 128:51-62. [PMID: 20209499 DOI: 10.1002/ijc.25308] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Although the connexin32 (Cx32)-mediated gap junction is abolished in hepatocellular carcinoma (HCC), the expression of cytoplasmic Cx32 tends to increase in correspondence with the grade of malignancy. Establishing a Tet-off expression system in human nonmetastatic HuH7 HCC cells where cytoplasmic Cx32 was overexpressed by doxycycline (Dox) withdrawal, we previously demonstrated that overexpression of cytoplasmic Cx32 made HuH7 cells metastatic in mice. In our study, hypothesizing that the cytoplasmic Cx32-induced metastasis may involve expansion of the cancer stem cell (CSC) population, we examined whether cytoplasmic Cx32 controlled the size of the side population (SP) in HuH7 Tet-off Cx32 cells. Fluorescence-activated cell sorting revealed that SP was expanded in a Dox-free medium compared with a Dox-supplemented one. Although cytoplasmic Cx32 did not block maturation from SP to non-SP, purified SP reconstituted a larger SP fraction in the Dox-free medium than in the Dox-supplemented one. Furthermore, although SP from HuH7 Tet-off mock cells formed a similar number of CSC spheres of a similar size whether with or without Dox, SP from HuH7 Tet-off Cx32 cells developed a greater number of larger CSC spheres in the Dox-free medium than in the Dox-supplemented one. Taken together, these results suggest that accumulation of cytoplasmic Cx32 should enhance self-renewal of CSC to expand the CSC population in HCC.
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MESH Headings
- Animals
- Anti-Bacterial Agents/pharmacology
- Carcinoma, Hepatocellular/genetics
- Carcinoma, Hepatocellular/metabolism
- Carcinoma, Hepatocellular/pathology
- Cell Line, Tumor
- Cell Proliferation
- Connexins/genetics
- Connexins/metabolism
- Cytoplasm/drug effects
- Cytoplasm/metabolism
- Doxycycline/pharmacology
- Flow Cytometry
- Fluorescent Antibody Technique, Indirect
- Gene Expression/drug effects
- Humans
- Immunoblotting
- Liver Neoplasms, Experimental/genetics
- Liver Neoplasms, Experimental/metabolism
- Liver Neoplasms, Experimental/pathology
- Male
- Mice
- Mice, SCID
- Neoplasm Metastasis
- Neoplastic Stem Cells/metabolism
- Neoplastic Stem Cells/pathology
- Tetracycline/pharmacology
- Transplantation, Heterologous
- Gap Junction beta-1 Protein
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Affiliation(s)
- Yohei Kawasaki
- Department of Molecular and Tumour Pathology, Akita University Graduate School of Medicine, Akita, Japan
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Prognostic value of connexin43 expression in patients with clinically localized prostate cancer. Prostate Cancer Prostatic Dis 2010; 14:90-5. [PMID: 21173791 DOI: 10.1038/pcan.2010.51] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Connexins (Cxs) are a family of transmembrane proteins that build cell-to-cell channels in gap junctions. Gap junctions composed of Cxs have an essential role in intercellular communication, adhesion and cell differentiation. Several studies investigated the role of connexin43 (Cx43) in different carcinomas; however, none investigated its prognostic role in prostate cancer. Cx43 expression and relationship with established prognostic features were assessed in a cohort of 102 patients treated with radical prostatectomy for clinically localized prostate adenocarcinoma. Cx43 expression in prostate cancer was significantly associated with established features indicative of worse prognosis, such as follow-up time (P < 0.001) and preoperative PSA (P < 0.007). Patients with lower Cx43 expressions in tumours have shorter follow-up time, which indicated shorter disease-free survival and higher preoperative PSA values. Furthermore, tumours with positive surgical margins (P < 0.001) showed significantly lower Cx43 expression compared with tumours without this feature. In univariate (P < 0.001) and multivariate (P = 0.014) analyses, decreased Cx43 expression was found to be a significant predictor of biochemical recurrence free-survival. Study results show the association of decreased Cx43 expression with prostate cancer progression. Moreover, Cx43 could serve as an additional prognostic marker and used together with traditional prognostic markers might help in further stratifying the risk of disease progression in patients with prostate cancer.
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Govindarajan R, Chakraborty S, Johnson KE, Falk MM, Wheelock MJ, Johnson KR, Mehta PP. Assembly of connexin43 into gap junctions is regulated differentially by E-cadherin and N-cadherin in rat liver epithelial cells. Mol Biol Cell 2010; 21:4089-107. [PMID: 20881055 PMCID: PMC2993739 DOI: 10.1091/mbc.e10-05-0403] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Cadherins have been thought to facilitate the assembly of connexins (Cxs) into gap junctions (GJs) by enhancing cell-cell contact, however the molecular mechanisms involved in this process have remained unexplored. We examined the assembly of GJs composed of Cx43 in isogenic clones derived from immortalized and nontransformed rat liver epithelial cells that expressed either epithelial cadherin (E-Cad), which curbs the malignant behavior of tumor cells, or neuronal cadherin (N-Cad), which augments the invasive and motile behavior of tumor cells. We found that N-cad expression attenuated the assembly of Cx43 into GJs, whereas E-Cad expression facilitated the assembly. The expression of N-Cad inhibited GJ assembly by causing endocytosis of Cx43 via a nonclathrin-dependent pathway. Knock down of N-Cad by ShRNA restored GJ assembly. When both cadherins were simultaneously expressed in the same cell type, GJ assembly and disassembly occurred concurrently. Our findings demonstrate that E-Cad and N-Cad have opposite effects on the assembly of Cx43 into GJs in rat liver epithelial cells. These findings imply that GJ assembly and disassembly are the down-stream targets of the signaling initiated by E-Cad and N-Cad, respectively, and may provide one possible explanation for the disparate role played by these cadherins in regulating cell motility and invasion during tumor progression and invasion.
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Affiliation(s)
- Rajgopal Govindarajan
- Department of Biochemistry and Molecular Biology, Eppley Institute for Research in Cancer and Allied Diseases, Eppley Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
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Chakraborty S, Mitra S, Falk MM, Caplan SH, Wheelock MJ, Johnson KR, Mehta PP. E-cadherin differentially regulates the assembly of Connexin43 and Connexin32 into gap junctions in human squamous carcinoma cells. J Biol Chem 2010; 285:10761-76. [PMID: 20086013 PMCID: PMC2856283 DOI: 10.1074/jbc.m109.053348] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2009] [Revised: 12/31/2009] [Indexed: 02/06/2023] Open
Abstract
It is as yet unknown how the assembly of connexins (Cx) into gap junctions (GJ) is initiated upon cell-cell contact. We investigated whether the trafficking and assembly of Cx43 and Cx32 into GJs were contingent upon cell-cell adhesion mediated by E-cadherin. We also examined the role of the carboxyl termini of these Cxs in initiating the formation of GJs. Using cadherin and Cx-null cells, and by introducing Cx43 and Cx32, either alone or in combination with E-cadherin, our studies demonstrated that E-cadherin-mediated cell-cell adhesion was neither essential nor sufficient to initiate GJ assembly de novo in A431D human squamous carcinoma cells. However, E-cadherin facilitated the growth and assembly of preformed GJs composed of Cx43, although the growth of cells on Transwell filters was required to initiate the assembly of Cx32. Our results also documented that the carboxyl termini of both Cxs were required in this cell type to initiate the formation of GJs de novo. Our findings also showed that GJ puncta composed of Cx43 co-localized extensively with ZO-1 and actin fibers at cell peripheries and that ZO-1 knockdown attenuated Cx43 assembly. These findings suggest that the assembly of Cx43 and Cx32 into GJs is differentially modulated by E-cadherin-mediated cell-cell adhesion and that direct or indirect cross-talk between carboxyl tails of Cxs and actin cytoskeleton via ZO-1 may regulate GJ assembly and growth.
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Affiliation(s)
- Souvik Chakraborty
- From the Department of Biochemistry and Molecular Biology, Eppley Institute for Research in Cancer and Allied Diseases, Eppley Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198 and
| | - Shalini Mitra
- From the Department of Biochemistry and Molecular Biology, Eppley Institute for Research in Cancer and Allied Diseases, Eppley Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198 and
| | - Matthias M. Falk
- the Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania 18015
| | - Steve H. Caplan
- From the Department of Biochemistry and Molecular Biology, Eppley Institute for Research in Cancer and Allied Diseases, Eppley Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198 and
| | - Margaret J. Wheelock
- From the Department of Biochemistry and Molecular Biology, Eppley Institute for Research in Cancer and Allied Diseases, Eppley Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198 and
| | - Keith R. Johnson
- From the Department of Biochemistry and Molecular Biology, Eppley Institute for Research in Cancer and Allied Diseases, Eppley Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198 and
| | - Parmender P. Mehta
- From the Department of Biochemistry and Molecular Biology, Eppley Institute for Research in Cancer and Allied Diseases, Eppley Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198 and
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Tang M, Asamoto M, Ogawa K, Naiki-Ito A, Sato S, Takahashi S, Shirai T. Induction of apoptosis in the LNCaP human prostate carcinoma cell line and prostate adenocarcinomas of SV40T antigen transgenic rats by the Bowman-Birk inhibitor. Pathol Int 2010; 59:790-6. [PMID: 19883429 DOI: 10.1111/j.1440-1827.2009.02445.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The soybean-derived serine protease inhibitor, Bowman-Birk inhibitor (BBI), has been reported as a potent chemoprevention agent against several types of tumors. The present study was undertaken to evaluate the effects of BBI on androgen-sensitive/dependent prostate cancers using a human prostate cancer cell (LNCaP) and the transgenic rats developing adenocarcinoma of the prostate (TRAP) model. Treatment of LNCaP prostate cancer cells with 500 microg/mL BBI resulted in inhibition of viability measured on WST-1 assays, with induction of connexin 43 (Cx43) and cleaved caspase-3 protein expression. Feeding of 3% roughly prepared BBI (BBIC) to TRAP from the age 3 weeks to 13 weeks resulted in significant reduction of the relative epithelial areas within the acinus and multiplicity of the adenocarcinomas in the lateral prostate lobes. Cx43- and terminal deoxynucleotidyl transferase mediated dUTP-biotin end labeling of fragmented DNA (TUNEL)-positive apoptotic cancer cells were more frequently observed in the lateral prostates treated with BBIC than in the controls. These in vivo and in vitro results suggest that BBI possesses chemopreventive activity associated with induction of Cx43 expression and apoptosis.
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Affiliation(s)
- MingXi Tang
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
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Hejmej A, Kotula-Balak M, Sadowska J, Bilińska B. Expression of connexin 43 protein in testes, epididymides and prostates of stallions. Equine Vet J 2010; 39:122-7. [PMID: 17378440 DOI: 10.2746/042516407x169393] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
REASONS FOR PERFORMING STUDY Connexin 43 (Cx43) is a ubiquitously distributed gap junction protein in testes and other reproductive tissues. Adjacent cells share ions and small metabolites through intercellular channels, which are present in gap junctions. Previously, Cx43 has not been reported in testes, epididymides and prostates either in healthy stallions or cryptorchid horses. OBJECTIVES To demonstrate the expression pattern of Cx43 in the reproductive tissues of stallions and examine whether naturally occurring bilateral cryptorchidism has any influence on distribution and expression of Cx43. METHODS The expression and the presence of Cx43 protein were detected by means of immunohistochemistry and Western blot analysis using a polyclonal rabbit anti-Cx43 antibody. RESULTS In stallions, gap junctions appeared as structures localised to cell-cell contacts between adjacent cells. In testes, Cx43 expression was detected in the interstitial tissue and seminiferous tubules, between Leydig and Sertoli, as well as Sertoli and germ cells. In epididymides, Cx43 was localised between epithelial cells, whereas in prostates, between secretory cells of the glandular epithelium. In the cryptorchid, a clear reduction of Cx43 signal was observed in all reproductive tissues. CONCLUSIONS Coupling of Leydig cells via gap junctions may suggest that steroidogenic function of the testis is under the influence of these intercellular channels. Within seminiferous tubules, the expression was found to be stage-specific, pointing to its role in coordinating spermatogenesis. Differential distribution of Cx43 protein in the reproductive tract of normal and cryptorchid stallions indicates that expression is clearly dependent on the physiological status of the horse. POTENTIAL RELEVANCE Detection of Cx43 expression in equine testicular, epididymal, and prostatic cells is important for a better understanding of the role of intercellular membrane channels in direct cell communication within the reproductive tract of stallions.
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Affiliation(s)
- A Hejmej
- Department of Endocrinology and Tissue Culture, Institute of Zoology, Jagiellonian University, Ingardena 6, 30-060 Kraków, Poland
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Liu Y, Zhang X, Li ZJ, Chen XH. Up-regulation of Cx43 expression and GJIC function in acute leukemia bone marrow stromal cells post-chemotherapy. Leuk Res 2009; 34:631-40. [PMID: 19910046 DOI: 10.1016/j.leukres.2009.10.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Revised: 09/10/2009] [Accepted: 10/14/2009] [Indexed: 10/20/2022]
Abstract
Gap junction intercellular communication (GJIC) among bone marrow stromal cells (BMSCs) most frequently occurs through a channel composed of connexin43 (Cx43). Dysregulation of connexin expression is believed to have a role in carcinogenesis. In earlier work, we found that in acute leukemia BMSCs, expression of Cx43 and functioning GJIC declined. However, there has been no evaluation of whether GJIC in BMSCs in complete remission (CR) post-chemotherapy is different from GJIC pre-chemotherapy. We studied Cx43 expression and tested GJIC function in human bone marrow cultures under different physiological and pathological conditions. To assay Cx43 expression we used immunocytochemistry, laser scan confocal microscopy (LSCM), flow cytometry and RT-PCR. The results showed that the expression level of Cx43 and its mRNA in acute leukemia BMSCs post-chemotherapy was significantly higher and similar to normal levels than in primary acute leukemia BMSCs (p<0.01). Functional tests in cultures using dye transfer and fluorescence recovery after photobleaching (FRAP) assays showed that the function of GJIC in acute leukemia BMSCs was significantly improved following effective chemotherapy. Our findings suggest Cx43 and GJIC might be involved in the courses of occurrence, development and termination of acute leukemia, and effective chemotherapy could improve Cx43 expression and GJIC function that were dysfunctional prior to treatment.
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Affiliation(s)
- Yao Liu
- Department of Hematology, Xinqiao Hospital, The Third Military Medical University, Shapingba District, Xinqiao Street, Chongqing 400037, China
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