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De A, Lattier JM, Morales JE, Kelly JR, Zheng X, Chen Z, Sebastian S, Nassiri Toosi Z, Huse JT, Lang FF, McCarty JH. Glial Cell Adhesion Molecule (GlialCAM) Determines Proliferative versus Invasive Cell States in Glioblastoma. J Neurosci 2023; 43:8043-8057. [PMID: 37722850 PMCID: PMC10669794 DOI: 10.1523/jneurosci.1401-23.2023] [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: 08/01/2023] [Revised: 09/08/2023] [Accepted: 09/13/2023] [Indexed: 09/20/2023] Open
Abstract
The malignant brain cancer glioblastoma (GBM) contains groups of highly invasive cells that drive tumor progression as well as recurrence after surgery and chemotherapy. The molecular mechanisms that enable these GBM cells to exit the primary mass and disperse throughout the brain remain largely unknown. Here we report using human tumor specimens and primary spheroids from male and female patients that glial cell adhesion molecule (GlialCAM), which has normal roles in brain astrocytes and is mutated in the developmental brain disorder megalencephalic leukoencephalopathy with subcortical cysts (MLC), is differentially expressed in subpopulations of GBM cells. High levels of GlialCAM promote cell-cell adhesion and a proliferative GBM cell state in the tumor core. In contrast, GBM cells with low levels of GlialCAM display diminished proliferation and enhanced invasion into the surrounding brain parenchyma. RNAi-mediated inhibition of GlialCAM expression leads to activation of proinvasive extracellular matrix adhesion and signaling pathways. Profiling GlialCAM-regulated genes combined with cross-referencing to single-cell transcriptomic datasets validates functional links among GlialCAM, Mlc1, and aquaporin-4 in the invasive cell state. Collectively, these results reveal an important adhesion and signaling axis comprised of GlialCAM and associated proteins including Mlc1 and aquaporin-4 that is critical for control of GBM cell proliferation and invasion status in the brain cancer microenvironment.SIGNIFICANCE STATEMENT Glioblastoma (GBM) contains heterogeneous populations of cells that coordinately drive proliferation and invasion. We have discovered that glial cell adhesion molecule (GlialCAM)/hepatocyte cell adhesion molecule (HepaCAM) is highly expressed in proliferative GBM cells within the tumor core. In contrast, GBM cells with low levels of GlialCAM robustly invade into surrounding brain tissue along blood vessels and white matter. Quantitative RNA sequencing identifies various GlialCAM-regulated genes with functions in cell-cell adhesion and signaling. These data reveal that GlialCAM and associated signaling partners, including Mlc1 and aquaporin-4, are key factors that determine proliferative and invasive cell states in GBM.
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Affiliation(s)
- Arpan De
- Department of Neurosurgery, MD Anderson Cancer Center, The University of Texas, Houston, Texas 77030
| | - John M Lattier
- Department of Neurosurgery, MD Anderson Cancer Center, The University of Texas, Houston, Texas 77030
| | - John E Morales
- Department of Neurosurgery, MD Anderson Cancer Center, The University of Texas, Houston, Texas 77030
| | - Jack R Kelly
- Department of Neurosurgery, MD Anderson Cancer Center, The University of Texas, Houston, Texas 77030
| | - Xiaofeng Zheng
- Department of Bioinformatics and Computational Biology, MD Anderson Cancer Center, The University of Texas, Houston, Texas 77030
| | - Zhihua Chen
- Department of Neurosurgery, MD Anderson Cancer Center, The University of Texas, Houston, Texas 77030
| | - Sumod Sebastian
- Department of Neurosurgery, MD Anderson Cancer Center, The University of Texas, Houston, Texas 77030
| | - Zahra Nassiri Toosi
- Department of Neurosurgery, MD Anderson Cancer Center, The University of Texas, Houston, Texas 77030
| | - Jason T Huse
- Department of Pathology, MD Anderson Cancer Center, The University of Texas, Houston, Texas 77030
| | - Frederick F Lang
- Department of Neurosurgery, MD Anderson Cancer Center, The University of Texas, Houston, Texas 77030
| | - Joseph H McCarty
- Department of Neurosurgery, MD Anderson Cancer Center, The University of Texas, Houston, Texas 77030
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Baldwin KT, Tan CX, Strader ST, Jiang C, Savage JT, Elorza-Vidal X, Contreras X, Rülicke T, Hippenmeyer S, Estévez R, Ji RR, Eroglu C. HepaCAM controls astrocyte self-organization and coupling. Neuron 2021; 109:2427-2442.e10. [PMID: 34171291 PMCID: PMC8547372 DOI: 10.1016/j.neuron.2021.05.025] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 04/19/2021] [Accepted: 05/19/2021] [Indexed: 10/21/2022]
Abstract
Astrocytes extensively infiltrate the neuropil to regulate critical aspects of synaptic development and function. This process is regulated by transcellular interactions between astrocytes and neurons via cell adhesion molecules. How astrocytes coordinate developmental processes among one another to parse out the synaptic neuropil and form non-overlapping territories is unknown. Here we identify a molecular mechanism regulating astrocyte-astrocyte interactions during development to coordinate astrocyte morphogenesis and gap junction coupling. We show that hepaCAM, a disease-linked, astrocyte-enriched cell adhesion molecule, regulates astrocyte competition for territory and morphological complexity in the developing mouse cortex. Furthermore, conditional deletion of Hepacam from developing astrocytes significantly impairs gap junction coupling between astrocytes and disrupts the balance between synaptic excitation and inhibition. Mutations in HEPACAM cause megalencephalic leukoencephalopathy with subcortical cysts in humans. Therefore, our findings suggest that disruption of astrocyte self-organization mechanisms could be an underlying cause of neural pathology.
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Affiliation(s)
- Katherine T Baldwin
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA.
| | - Christabel X Tan
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Samuel T Strader
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Changyu Jiang
- Department of Anesthesiology and Center for Translational Pain Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | - Justin T Savage
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Xabier Elorza-Vidal
- Unitat de Fisiología, Departament de Ciències Fisiològiques, IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Spain
| | - Ximena Contreras
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Thomas Rülicke
- Institute of Laboratory Animal Science, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Simon Hippenmeyer
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Raúl Estévez
- Unitat de Fisiología, Departament de Ciències Fisiològiques, IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain
| | - Ru-Rong Ji
- Department of Anesthesiology and Center for Translational Pain Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | - Cagla Eroglu
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA; Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA; Duke Institute for Brain Sciences (DIBS), Durham, NC 27710, USA; Duke University Regeneration Next Initiative, Durham, NC 27710, USA.
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3
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Megalencephalic Leukoencephalopathy with Subcortical Cysts Disease-Linked MLC1 Protein Favors Gap-Junction Intercellular Communication by Regulating Connexin 43 Trafficking in Astrocytes. Cells 2020; 9:cells9061425. [PMID: 32521795 PMCID: PMC7348769 DOI: 10.3390/cells9061425] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 05/29/2020] [Accepted: 06/03/2020] [Indexed: 01/06/2023] Open
Abstract
Astrocytes, the most numerous cells of the central nervous system, exert critical functions for brain homeostasis. To this purpose, astrocytes generate a highly interconnected intercellular network allowing rapid exchange of ions and metabolites through gap junctions, adjoined channels composed of hexamers of connexin (Cx) proteins, mainly Cx43. Functional alterations of Cxs and gap junctions have been observed in several neuroinflammatory/neurodegenerative diseases. In the rare leukodystrophy megalencephalic leukoencephalopathy with subcortical cysts (MLC), astrocytes show defective control of ion/fluid exchanges causing brain edema, fluid cysts, and astrocyte/myelin vacuolation. MLC is caused by mutations in MLC1, an astrocyte-specific protein of elusive function, and in GlialCAM, a MLC1 chaperon. Both proteins are highly expressed at perivascular astrocyte end-feet and astrocyte-astrocyte contacts where they interact with zonula occludens-1 (ZO-1) and Cx43 junctional proteins. To investigate the possible role of Cx43 in MLC pathogenesis, we studied Cx43 properties in astrocytoma cells overexpressing wild type (WT) MLC1 or MLC1 carrying pathological mutations. Using biochemical and electrophysiological techniques, we found that WT, but not mutated, MLC1 expression favors intercellular communication by inhibiting extracellular-signal-regulated kinase 1/2 (ERK1/2)-mediated Cx43 phosphorylation and increasing Cx43 gap-junction stability. These data indicate MLC1 regulation of Cx43 in astrocytes and Cx43 involvement in MLC pathogenesis, suggesting potential target pathways for therapeutic interventions.
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Wu M, Moh MC, Schwarz H. HepaCAM associates with connexin 43 and enhances its localization in cellular junctions. Sci Rep 2016; 6:36218. [PMID: 27819278 PMCID: PMC5098153 DOI: 10.1038/srep36218] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 10/12/2016] [Indexed: 12/30/2022] Open
Abstract
HepaCAM (GlialCAM) is frequently deleted in carcinomas, and reintroduction of hepaCAM into transformed cell lines reduces cellular growth and induces senescence. Mutations in HEPACAM give rise to the neurodegenerative disease megalencephalic leukoencephalopathy with subcortical cysts (MLC) since mutated hepaCAM prevents shuttling of MLC1 protein to astrocytic junctions in the plasma membrane. Here we identify that hepaCAM associates with connexin 43, a main component of gap junctions, and enhances connexin 43 localization to the plasma membrane at cellular junctions. HepaCAM also increases the levels of connexin 43, not by enhancing its transcription but by stabilizing connexin 43 protein. In the absence of hepaCAM, connexin 43 undergoes a faster degradation via the lysosomal pathway while proteasomal degradation seems not to be involved. Mutations in hepaCAM that cause MLC, or neutralization of hepaCAM by antibodies disrupt its association with connexin 43 at cellular junctions. By discovering the requirement of hepaCAM for localizing connexin 43, a well-established tumor suppressor, to cellular junctions and stabilizing it there, this study suggests a mechanism by which deletion of hepaCAM may support tumor progression.
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Affiliation(s)
- Meihui Wu
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597.,Immunology Programme, Life Sciences Institute, National University of Singapore, Singapore 117456
| | - Mei Chung Moh
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597.,Immunology Programme, Life Sciences Institute, National University of Singapore, Singapore 117456
| | - Herbert Schwarz
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597.,Immunology Programme, Life Sciences Institute, National University of Singapore, Singapore 117456
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Wang X, Chen E, Yang X, Wang Y, Quan Z, Wu X, Luo C. 5-azacytidine inhibits the proliferation of bladder cancer cells via reversal of the aberrant hypermethylation of the hepaCAM gene. Oncol Rep 2015; 35:1375-84. [PMID: 26677113 DOI: 10.3892/or.2015.4492] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Accepted: 07/24/2015] [Indexed: 11/06/2022] Open
Abstract
Hepatocyte cell adhesion molecule (hepaCAM), a tumor-suppressor gene, is rarely expressed in bladder carcinoma. However, little is known concerning the mechanisms of low hepaCAM expression in bladder cancer. Abnormal hypermethylation in the promoter plays a crucial role in cancer by silencing tumor-suppressor genes, which is catalyzed by DNA methyltransferases (DNMTs). In the present study, a total of 31 bladder cancer and 22 adjacent tissues were assessed by immunohistochemistry to detect DNMT3A/3B and hepaCAM expression. Methylation of hepaCAM was determined by methylation‑specific polymerase chain reaction (MSP). The mRNA and protein levels of DNMT3A/3B and hepaCAM were determined by RT-PCR and western blot analysis after treatment with 5-azacytidine (AZAC). Following AZAC treatment, the proliferation of bladder cancer cells was detected by CCK-8 and colony formation assays. Cell cycle distribution was examined by flow cytometry. To further evaluate the tumor‑suppressive roles of AZAC and the involved mechanisms, the anti-tumorigenicity of AZAC was tested in vivo. The expression of DNMT3A/3B protein was markedly increased in the bladder carcinoma tissues (P<0.05), and had a negative linear correlation with hepaCAM expression in the same patients according to Pearson's analysis (r=-0.7176/-0.7127, P<0.05). The MSP results indicated that the hepaCAM gene was hypermethylated in three bladder cancer cell lines. Furthermore, we found that downregulation of DNMT3A/3B expression, after treatment with AZAC, reversed the hypermethylation and expression of hepaCAM in bladder cancer cells. In addition, AZAC inhibited the proliferation of bladder cancer cells and arrested cells at the G0/G1 phase. The in vivo results showed that expression of DNMT3A/3B and hepaCAM as well as tumor growth of nude mice were markedly altered which corresponded with the in vitro results. Due to the ability to reactivate expression of hepaCAM and inhibit growth of bladder cancer cells, AZAC may represent an effective treatment for bladder cancer.
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Affiliation(s)
- Xiaorong Wang
- Key Laboratory of Diagnostic Medicine designated by the Chinese Ministry of Education, Chongqing Medical University, Chongqing, P.R. China
| | - E Chen
- Key Laboratory of Diagnostic Medicine designated by the Chinese Ministry of Education, Chongqing Medical University, Chongqing, P.R. China
| | - Xue Yang
- Key Laboratory of Diagnostic Medicine designated by the Chinese Ministry of Education, Chongqing Medical University, Chongqing, P.R. China
| | - Yin Wang
- Key Laboratory of Diagnostic Medicine designated by the Chinese Ministry of Education, Chongqing Medical University, Chongqing, P.R. China
| | - Zhen Quan
- Department of Urology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, P.R. China
| | - Xiaohou Wu
- Department of Urology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, P.R. China
| | - Chunli Luo
- Key Laboratory of Diagnostic Medicine designated by the Chinese Ministry of Education, Chongqing Medical University, Chongqing, P.R. China
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Shao H, Gu Y, Ding J, Lu P, Ruan T, Lu W. HEPACAM inhibited the growth and migration of cancer cells in the progression of non-small cell lung cancer. Tumour Biol 2015; 37:2621-7. [PMID: 26392113 DOI: 10.1007/s13277-015-4084-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Accepted: 09/13/2015] [Indexed: 12/17/2022] Open
Abstract
Hepatocyte cell adhesion molecule (HEPACAM), a member of immunoglobulin superfamily, is an adhesion molecule. Although dysregulation of several adhesion molecules has been implicated in the progression of non-small cell lung cancer (NSCLC), the expression profile and functions of HEPACAM in NSCLC remains unknown. In this study, it was found that the expression of HEPACAM was downregulated in NSCLC tissues. Forced expression of HEPACAM in NSCLC cells inhibited the growth and migration of the cancer cells, while knocking down the expression of HEPACAM promoted cell growth, migration, and metastasis. In the molecular mechanism study, HEPACAM was found to be a negative regulator of beta-catenin/TCF signaling. Taken together, this study revealed the suppressive roles of HEPACAM in NSCLC and restoring the function of HEPACAM in NSCLC might be a promising strategy for the therapy.
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Affiliation(s)
- Huanzhang Shao
- Department of Critical Care Medicine, Henan Provincial People's Hospital, Affiliated of Zhengzhou University, Zhengzhou, 450003, China
| | - Yinjie Gu
- Department of Critical Care Medicine, Affiliated Yixing People's Hospital, Jiangsu University, Yixing, 214200, Jiangsu Province, China
| | - Junli Ding
- Department of Medical Oncology, Wuxi People's Hospital Affiliated to Nanjing Medical University, Wuxi, 214023, Jiangsu Province, China
| | - Peihua Lu
- Department of Medical Oncology, Wuxi People's Hospital Affiliated to Nanjing Medical University, Wuxi, 214023, Jiangsu Province, China
| | - Tingyan Ruan
- Department of Medical Oncology, Wuxi People's Hospital Affiliated to Nanjing Medical University, Wuxi, 214023, Jiangsu Province, China
| | - Wenbin Lu
- Department of Medical Oncology, Wujin People's Hospital Affiliated to Jiangsu University, 2 North Yongning Rd, Changzhou, 213002, Jiangsu Province, China.
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Disrupting MLC1 and GlialCAM and ClC-2 interactions in leukodystrophy entails glial chloride channel dysfunction. Nat Commun 2014; 5:3475. [PMID: 24647135 DOI: 10.1038/ncomms4475] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 02/18/2014] [Indexed: 11/08/2022] Open
Abstract
Defects in the astrocytic membrane protein MLC1, the adhesion molecule GlialCAM or the chloride channel ClC-2 underlie human leukoencephalopathies. Whereas GlialCAM binds ClC-2 and MLC1, and modifies ClC-2 currents in vitro, no functional connections between MLC1 and ClC-2 are known. Here we investigate this by generating loss-of-function Glialcam and Mlc1 mouse models manifesting myelin vacuolization. We find that ClC-2 is unnecessary for MLC1 and GlialCAM localization in brain, whereas GlialCAM is important for targeting MLC1 and ClC-2 to specialized glial domains in vivo and for modifying ClC-2's biophysical properties specifically in oligodendrocytes (OLs), the cells chiefly affected by vacuolization. Unexpectedly, MLC1 is crucial for proper localization of GlialCAM and ClC-2, and for changing ClC-2 currents. Our data unmask an unforeseen functional relationship between MLC1 and ClC-2 in vivo, which is probably mediated by GlialCAM, and suggest that ClC-2 participates in the pathogenesis of megalencephalic leukoencephalopathy with subcortical cysts.
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Tan B, Tan J, Du H, Quan Z, Xu X, Jiang X, Luo C, Wu X. HepaCAM inhibits clear cell renal carcinoma 786-0 cell proliferation via blocking PKCε translocation from cytoplasm to plasma membrane. Mol Cell Biochem 2014; 391:95-102. [PMID: 24515280 DOI: 10.1007/s11010-014-1991-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 01/29/2014] [Indexed: 01/01/2023]
Abstract
Hepatocyte cell adhesion molecule (HepaCAM) plays a crucial role in tumor progression and has been recognized as a novel tumor suppressor gene. The high protein expression level of protein kinase Cε (PKCε) has been discovered in many tumor types. In the present study, we determined HepaCAM and PKCε protein levels in human clear cell renal cell carcinoma (ccRCC) tissues and analyzed the correlation between them. We observed an inverse relationship in the expression of HepaCAM and PKCε in ccRCC and adjacent normal tissues. In ccRCC tissue, HepaCAM expression was undetectable while PKCε expression was high; the opposite was found in the adjacent normal tissue. Western blot analysis demonstrated that PKCε cytosolic protein levels increased while plasma membrane protein levels decreased without any change in total protein following infection of the ccRCC cell line 786-0 with adenovirus-GFP-HepaCAM (Ad-GFP-HepaCAM). Moreover, the application of Ad-GFP-HepaCAM combined with a PKCε-specific translocation inhibitor (εV1-2) effectively inhibited 786-0 cell growth. Ad-mediated expression of HepaCAM in 786-0 cells reduced the levels of phosphorylated AKT and cyclin D1 and inhibited cell proliferation. In summary, our studies point to interesting connections between HepaCAM and PKCε in tissues and in vitro. HepaCAM may prevent the translocation of PKCε from cytosolic to particulate fractions, resulting in the inhibition of 786-0 cell proliferation. Therapeutic manipulation of these novel protein targets may provide new ways of treating ccRCC.
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Affiliation(s)
- Bing Tan
- Department of Urology, The First Affiliated Hospital of Chongqing Medical University, No. 1, Youyi Road, Yuanjiagang, Yuzhong District, Chongqing, 400016, People's Republic of China
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Barrallo-Gimeno A, Estévez R. GlialCAM, a glial cell adhesion molecule implicated in neurological disease. ADVANCES IN NEUROBIOLOGY 2014; 8:47-59. [PMID: 25300132 DOI: 10.1007/978-1-4614-8090-7_3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
GlialCAM (also named HepaCAM) is a cell adhesion molecule expressed mainly in glial cells from the central nervous system and the liver. GlialCAM plays different roles according to its cellular context. In epithelial cell lines, overexpression of GlialCAM increases cell adhesion and motility but also inhibits cell growth in tumor cell lines, leading to senescence. In glial cells, however, its function is quite different. GlialCAM acts a regulator of subcellular traffic of MLC1, a protein with unknown function involved in the pathogenesis of megalencephalic leukoencephalopathy with subcortical cysts (MLC), a rare neurological condition. Moreover, GlialCAM itself has been found to be responsible for some of the cases of this disease. Additionally, GlialCAM also works as an auxiliary subunit of the chloride channel ClC-2, regulating its targeting to cell-cell junctions and modifying its functional properties. In summary, GlialCAM has different functions not only related to its adhesive nature, and defects in these functions lead to neurological disease.
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Tao J, Liu Q, Wu X, Xu X, Zhang Y, Wang Q, Luo C. Identification of hypermethylation in hepatocyte cell adhesion molecule gene promoter region in bladder carcinoma. Int J Med Sci 2013; 10:1860-7. [PMID: 24324362 PMCID: PMC3856376 DOI: 10.7150/ijms.6460] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 06/18/2013] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Epigenetic regulation such as aberrant hypermethylation of CpG islands in promoter plays a key role in tumorigenesis. 5-Aza-2'-deoxycytidine (5-aza-CdR) which is a potent inhibitor of DNA methylation can reverse the abnormal hypermethylation of the silenced tumor suppressor genes (TSGs). It has been reported that hepatocyte cell adhesion molecule (hepaCAM) acts as a tumor suppressor gene and expression of its mRNA and protein were down-regulated in bladder cancer. Over-expression of hepaCAM can inhibit cancer growth and arrest renal cancer cells at G0/G1 phase. In this study, we investigated the methylation status of hepaCAM gene, as well as the influence of 5-aza-CdR on expression of hepaCAM gene in bladder cancer cells. METHODS CpG islands in hepaCAM promoter and methprimers were predicted and designed using bioinformatics program. Methylation status of hepaCAM promoter was evaluated in bladder cancer tissues and two cell lines (T24 and BIU-87) by Methylation-specific PCR; Western blot and Immunofluorescence were used to detect expression of hepaCAM protein after 5-aza-CdR treatment; Flow cytometry assay was performed to determine effectiveness of 5-aza-CdR on cell cycle profile. RESULTS CpG island in promoter of hepaCAM gene was hyper-methylated both in bladder carcinoma tissues and cell lines (T24 and BIU-87). Otherwise, aberrant methylation of its promoter was associated with its decreased expression. Hypermethylation of hepaCAM gene was reversed and expression of its mRNA and protein were re-activated in two cell lines by DNA methyltransferases inhibitor 5-aza-CdR. Flow cytometry assay demonstrated that 5-aza-CdR can inhibit growth of cancer cells by arresting cancer cells at G0/G1 phase. CONCLUSION Abnormal hypermethylation in CpG island of hepaCAM promoter is involved in absence of hepaCAM gene expression when bladder cancer occurs. Re-activation of hepaCAM gene by 5-aza-CdR can inhibit growth of cancer cells and arrest cells at G0/G1 phase.
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Affiliation(s)
- Jia Tao
- 1. Department of Laboratory Diagnosis, Chongqing Medical University, Chongqing, 400016 China
| | - Qi Liu
- 1. Department of Laboratory Diagnosis, Chongqing Medical University, Chongqing, 400016 China
| | - Xiaohou Wu
- 2. Department of Urinary Surgery, First Hospital of Chongqing Medical University, Chongqing, 400016 China
| | - Xin Xu
- 1. Department of Laboratory Diagnosis, Chongqing Medical University, Chongqing, 400016 China
| | - Yanyi Zhang
- 1. Department of Laboratory Diagnosis, Chongqing Medical University, Chongqing, 400016 China
| | - Qiuju Wang
- 1. Department of Laboratory Diagnosis, Chongqing Medical University, Chongqing, 400016 China
| | - Chunli Luo
- 1. Department of Laboratory Diagnosis, Chongqing Medical University, Chongqing, 400016 China
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van der Knaap MS, Boor I, Estévez R. Megalencephalic leukoencephalopathy with subcortical cysts: chronic white matter oedema due to a defect in brain ion and water homoeostasis. Lancet Neurol 2012; 11:973-85. [PMID: 23079554 DOI: 10.1016/s1474-4422(12)70192-8] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is characterised by chronic white matter oedema. The disease has an infantile onset and leads to slow neurological deterioration in most cases, but, surprisingly, some patients recover. The first disease gene, MLC1, identified in 2001, is mutated in 75% of patients. At that time, nothing was known about MLC1 protein function and the pathophysiology of MLC. More recently, HEPACAM (also called GLIALCAM) has been identified as a second disease gene. GlialCAM serves as an escort for MLC1 and the chloride channel CLC2. The defect in MLC1 has been shown to hamper the cell volume regulation of astrocytes. One of the most important consequences involves the potassium siphoning process, which is essential in brain ion and water homoeostasis. An understanding of the mechanisms of white matter oedema in MLC is emerging. Further insight into the specific function of MLC1 is necessary to find treatment targets.
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Affiliation(s)
- Marjo S van der Knaap
- Department of Pediatrics/Child Neurology, VU University Medical Centre, Amsterdam, Netherlands.
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Zhang QL, Luo CL, Wu XH, Wang CY, Xu X, Zhang YY, Liu Q, Shen SL. HepaCAM induces G1 phase arrest and promotes c-Myc degradation in human renal cell carcinoma. J Cell Biochem 2012; 112:2910-9. [PMID: 21618595 DOI: 10.1002/jcb.23207] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Hepatocyte cell adhesion molecule (hepaCAM) encodes a generally inactive phosphorylated glycoprotein which mediates cancer cell proliferation, migration, and differentiation. We have reported that hepaCAM is down-regulated in renal cell carcinoma (RCC) and takes responsibility of cell growth inhibition. However, the precise mechanisms of hepaCAM inhibits cell growth is still unknown. In this study, we demonstrated that re-expression of hepaCAM can cause an accumulation in G0/G1 phase in 786-0 cells. This reaction was accompanied by a substantial reduction of c-Myc expression through using an ectopic hepaCAM expression system. Furthermore, we found a comparable decrease in proliferation and G0/G1 accumulation of 786-0 and RC-2 cells after treatment with a small molecule c-Myc inhibitor, 10058-F4. This indicated that the down regulation of c-Myc was an essential process in controlling growth inhibitory actions of hepaCAM. Nevertheless, re-expression of hepaCAM results in apparent reduction of c-Myc protein with no corresponding reduction of c-Myc mRNA. This suggests that this reaction might take place at a post-transcriptional level rather than transcriptional one. Consistent with these findings, hepaCAM decreased c-Myc stability by increasing the proportion of c-Myc phosphorylation on T58 which can be abrogated by a proteasomal inhibitor (MG132). Thus, our research implies that the decrease in c-Myc protein expression, resulting from ectopic expression of hepaCAM, may contribute to the inhibition of proliferation in these cells.
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Affiliation(s)
- Qiao-Lin Zhang
- Department of Laboratory Diagnosis, Chongqing Medical University, Chongqing 400016, China
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López-Hernández T, Sirisi S, Capdevila-Nortes X, Montolio M, Fernández-Dueñas V, Scheper GC, van der Knaap MS, Casquero P, Ciruela F, Ferrer I, Nunes V, Estévez R. Molecular mechanisms of MLC1 and GLIALCAM mutations in megalencephalic leukoencephalopathy with subcortical cysts. Hum Mol Genet 2011; 20:3266-77. [DOI: 10.1093/hmg/ddr238] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Yang S, Wu X, Luo C, Pan C, Pu J. Expression and clinical significance of hepaCAM and VEGF in urothelial carcinoma. World J Urol 2010; 28:473-8. [PMID: 20593288 DOI: 10.1007/s00345-010-0573-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Accepted: 05/28/2010] [Indexed: 11/28/2022] Open
Abstract
PURPOSE Investigate the expression of hepatocyte cell adhesion molecule (hepaCAM) and vascular endothelial growth factor (VEGF) mRNA in 55 cases of urothelial carcinoma to examine the potential relationship between hepaCAM and VEGF in urothelial carcinoma. METHODS Expression of hepaCAM and VEGF gene was determined by semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR) in 55 paired urothelial carcinoma specimens. T24 cells stably expressing hepaCAM gene were established by Lipofectamine 2000. RT-PCR and western blot analysis were used to detect gene and protein expression of hepaCAM and VEGF before and after transfection. MTT test was used to detect the effect of hepaCAM gene on the cell proliferation. RESULTS RT-PCR showed that hepaCAM expression level was significantly lower, and VEGF was significantly higher in urothelial carcinoma tissues than in adjacent tissues (P < 0.05, P < 0.05). hepaCAM and VEGF were strongly correlated with tumor stage (P < 0.05, P < 0.05). Spearman correlation analysis showed lower hepaCAM level was associated with higher VEGF level (r = -0.277 P = 0.041). Experiments with T24 cells in vitro demonstrated the expression of VEGF mRNA and protein were significantly decreased after transfection of hepaCAM gene (P < 0.05, P < 0.05). Expression of hepaCAM resulted in a significant inhibition of T24 cells proliferation (P < 0.05). CONCLUSION There is a close relationship between hepaCAM and VEGF in urothelial carcinoma. hepaCAM may be defined as a new target for diagnosis and anticancer therapy.
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Affiliation(s)
- Shuzhe Yang
- Key Laboratory of Laboratory Medical Diagnostics, Ministry of Education, Chongqing Medical University, Chongqing, 400016, China
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Functional significance of the hepaCAM gene in bladder cancer. BMC Cancer 2010; 10:83. [PMID: 20205955 PMCID: PMC2845116 DOI: 10.1186/1471-2407-10-83] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Accepted: 03/08/2010] [Indexed: 01/28/2023] Open
Abstract
Background The hepaCAM gene encodes a new immunoglobulin-like cell adhesion molecule, and its expression is suppressed in a variety of human cancers. Additionally, hepaCAM possesses properties often observed in tumor suppressor genes. However, the expression and biological function of hepaCAM has not been investigated in bladder cancer. Therefore we sought to examine hepaCAM expression and the relationship between its structure and function in human transitional cell carcinoma of bladder (TCCB). Materials and methods HepaCAM expression was evaluated in 28 normal and 34 TCCB bladder specimens and 2 TCCB cell lines using semi-quantitative RT-PCR. The wild-type hepaCAM and the extracellular domain-truncated mutant gene were transfected into the TCCB cell line T24, and the biological properties of both the wild-type gene and the domain-truncated mutant were then assessed. Results HepaCAM expression was down-regulated in 82% (28/34) of TCCB specimens and undetectable in the 2 TCCB cell lines tested. The localization of hepaCAM appeared to be dependent on cell density in T24 cells. In widely spread cells, hepaCAM accumulated on the perinuclear membrane and the cell surface protrusions, whereas in confluent cells, hepaCAM was predominantly localized at the sites of cell-cell contacts on the cell membrane. Functionally, hepaCAM expressed not only increased cell spreading, delayed cell detachment, enhanced wound healing and increased cell invasion; it also inhibited cell growth (P < 0.01). When the extracellular domain was deleted, the localization of hepaCAM was significantly altered, and it lost both its adhesive function and its influence on cell growth. Conclusions HepaCAM is involved in cell adhesion and growth control, and its expression is frequently silenced in TCCB. The extracellular domain of hepaCAM is essential to its physiological and biological functions.
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Sugimoto C, Maekawa S, Miyata S. OBCAM, an immunoglobulin superfamily cell adhesion molecule, regulates morphology and proliferation of cerebral astrocytes. J Neurochem 2010; 112:818-28. [DOI: 10.1111/j.1471-4159.2009.06513.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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