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Understanding the versatile roles and applications of EpCAM in cancers: from bench to bedside. Exp Hematol Oncol 2022; 11:97. [PMID: 36369033 PMCID: PMC9650829 DOI: 10.1186/s40164-022-00352-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 10/26/2022] [Indexed: 11/13/2022] Open
Abstract
Epithelial cell adhesion molecule (EpCAM) functions not only in physiological processes but also participates in the development and progression of cancer. In recent decades, extensive efforts have been made to decipher the role of EpCAM in cancers. Great advances have been achieved in elucidating its structure, molecular functions, pathophysiological mechanisms, and clinical applications. Beyond its well-recognized role as a biomarker of cancer stem cells (CSCs) or circulating tumor cells (CTCs), EpCAM exhibits novel and promising value in targeted therapy. At the same time, the roles of EpCAM in cancer progression are found to be highly context-dependent and even contradictory in some cases. The versatile functional modules of EpCAM and its communication with other signaling pathways complicate the study of this molecule. In this review, we start from the structure of EpCAM and focus on communication with other signaling pathways. The impacts on the biology of cancers and the up-to-date clinical applications of EpCAM are also introduced and summarized, aiming to shed light on the translational prospects of EpCAM.
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Barzaman K, Vafaei R, Samadi M, Kazemi MH, Hosseinzadeh A, Merikhian P, Moradi-Kalbolandi S, Eisavand MR, Dinvari H, Farahmand L. Anti-cancer therapeutic strategies based on HGF/MET, EpCAM, and tumor-stromal cross talk. Cancer Cell Int 2022; 22:259. [PMID: 35986321 PMCID: PMC9389806 DOI: 10.1186/s12935-022-02658-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 07/19/2022] [Indexed: 02/08/2023] Open
Abstract
As an intelligent disease, tumors apply several pathways to evade the immune system. It can use alternative routes to bypass intracellular signaling pathways, such as nuclear factor-κB (NF-κB), Wnt, and mitogen-activated protein (MAP)/phosphoinositide 3-kinase (PI3K)/mammalian target of rapamycin (mTOR). Therefore, these mechanisms lead to therapeutic resistance in cancer. Also, these pathways play important roles in the proliferation, survival, migration, and invasion of cells. In most cancers, these signaling pathways are overactivated, caused by mutation, overexpression, etc. Since numerous molecules share these signaling pathways, the identification of key molecules is crucial to achieve favorable consequences in cancer therapy. One of the key molecules is the mesenchymal-epithelial transition factor (MET; c-Met) and its ligand hepatocyte growth factor (HGF). Another molecule is the epithelial cell adhesion molecule (EpCAM), which its binding is hemophilic. Although both of them are involved in many physiologic processes (especially in embryonic stages), in some cancers, they are overexpressed on epithelial cells. Since they share intracellular pathways, targeting them simultaneously may inhibit substitute pathways that tumor uses to evade the immune system and resistant to therapeutic agents.
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Mal A, Dey P, Hayes RM, McCarthy JV, Ray A, De A. In Silico Identification of Potential Phosphorylation in the Cytoplasmic Domain of Epithelial Cell Adhesion Molecule. ACS OMEGA 2020; 5:30808-30816. [PMID: 33324790 PMCID: PMC7726786 DOI: 10.1021/acsomega.0c02113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 10/20/2020] [Indexed: 06/12/2023]
Abstract
The epithelial cell adhesion molecule (EpCAM) is a transmembrane cell adhesion glycoprotein, which primarily contributes to stemness, proliferation, and metastasis properties of tumor cells. Regulated intramembrane proteolysis by ADAM proteases and γ-secretase cleaves EpCAM into an ∼27 kDa soluble extracellular and an ∼4 kDa cytoplasmic domain (EpICD). After the EpICD fragment is released inside the cell, the formation of a nuclear signaling complex with the FHL2 molecule is critical for exerting its regulatory role. Trop-2, a homologous protein of EpCAM, undergoes phosphorylation in its cytoplasmic domain (Trop-IC). The phosphorylation of Trop-2 is reported to be crucial for its function. This led us to ask the fundamental question if EpCAM does undergo similar post-translational modification(PTM) like its homologous protein to carry out its diverse biological function. Here, we identify a putative phosphorylation site at Tyr297 located in the cytoplasmic domain of EpCAM. Molecular dynamic simulation (MDS) of 90 ns was carried out to understand the biological/functional relevance of the putative phosphorylation. It was observed that this phosphorylation stabilizes the α-helical structure of the EpICD. Though Tyr297 does not affect the γ-secretase mediated cleavage of EpCAM, it affects the binding of EpICD to FHL2. Docking analysis revealed that phosphorylation mediated structural stability of EpICD positively impacts its binding affinity with FHL2, which was further validated using 100 ns MDS. Phosphorylated EpICD forms higher numbers of hydrogen bonds, salt bridges, and other non-bonded interactions with FHL2, leading to enhanced interactions. This in silico study reveals a potential PTM in the EpICD, providing the basis for future research in understanding the mechanism behind the diverse biological function of EpCAM.
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Affiliation(s)
- Arijit Mal
- Molecular Functional
Imaging Laboratory, ACTREC, Tata Memorial Centre, Navi Mumbai 410210, India
- Life Science, Homi Bhaba National Institute, Mumbai 400094, India
| | - Pranay Dey
- Molecular Functional
Imaging Laboratory, ACTREC, Tata Memorial Centre, Navi Mumbai 410210, India
- Life Science, Homi Bhaba National Institute, Mumbai 400094, India
| | - Robert Michael Hayes
- Signal Transduction Laboratory, School of Biochemistry
& Cell Biology, University College Cork, Cork T12 K8AF, Ireland
| | - Justin V. McCarthy
- Signal Transduction Laboratory, School of Biochemistry
& Cell Biology, University College Cork, Cork T12 K8AF, Ireland
| | - Arjun Ray
- Computational Biology, Indraprastha
Institute of Information Technology, Delhi 110020, India
| | - Abhijit De
- Molecular Functional
Imaging Laboratory, ACTREC, Tata Memorial Centre, Navi Mumbai 410210, India
- Life Science, Homi Bhaba National Institute, Mumbai 400094, India
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Fonseca ICCFE, da Luz FAC, Uehara IA, Silva MJB. Cell-adhesion molecules and their soluble forms: Promising predictors of "tumor progression" and relapse in leukemia. Tumour Biol 2018; 40:1010428318811525. [PMID: 30486756 DOI: 10.1177/1010428318811525] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Some surface markers are used to discriminate certain leukemic subpopulations that retain a greater oncogenic potential than others, and, for this reason, they were termed as leukemic stem cells, similar to the concept of cancer stem cells in carcinoma. Among these surface markers are proteins involved in cell-cell adhesion or cell-matrix adhesion, and they may play a role in the relapse of leukemia, similar to metastasis in carcinomas. The most important are epithelial cadherin, neural cadherin, epithelial cell-adhesion molecule, and CD44, which can be cleaved and released, and their soluble forms were found increased in serum levels of cancer patients, being implicated, in some cases, with progression, metastases, and relapse. In this review, we highlighted the role of these four adhesion molecules in carcinomas and hematological malignancies, mainly leukemia, and discuss if the serum levels of soluble forms can be correlated with the surface protein status on the leukemic cells. Accession of the soluble forms looks attractive, but their use as markers in cancer must be studied in association with other parameters, as there are significant changes in levels in other pathological conditions besides cancer. Studies correlating the levels of the forms with the status of the membrane-bound proteins in leukemic (stem) cells and correlating those parameters with relapse in leukemia may afford important knowledge and applicability of those serum markers in clinical practice. For instance, the expression of the membrane-bound forms of these adhesion proteins may have promising clinical use in leukemia and other hematological malignancies.
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Affiliation(s)
| | - Felipe Andrés Cordero da Luz
- 1 Laboratory of Tumor Biomarkers and Osteoimmunology, Institute of Biomedical Sciences, Federal University of Uberlândia, Uberlândia, Brazil
- 2 Nucleus of Cancer Prevention and Research, Cancer Hospital, Federal University of Uberlândia, Uberlândia, Brazil
| | - Isadora Akemi Uehara
- 1 Laboratory of Tumor Biomarkers and Osteoimmunology, Institute of Biomedical Sciences, Federal University of Uberlândia, Uberlândia, Brazil
| | - Marcelo José Barbosa Silva
- 1 Laboratory of Tumor Biomarkers and Osteoimmunology, Institute of Biomedical Sciences, Federal University of Uberlândia, Uberlândia, Brazil
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Drug-induced expression of EpCAM contributes to therapy resistance in esophageal adenocarcinoma. Cell Oncol (Dordr) 2018; 41:651-662. [PMID: 30116994 PMCID: PMC6244739 DOI: 10.1007/s13402-018-0399-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/04/2018] [Indexed: 02/06/2023] Open
Abstract
Background With a less than 5% overall survival rate, esophageal adenocarcinoma (EAC) is one of the leading causes of death in the United States. Epithelial cell adhesion molecule (EpCAM) is a cancer stem cell (CSC) marker that is expressed in various epithelial carcinomas, including EAC. Accumulating evidence indicates that CSC subpopulations can initiate cancer development and, in addition, drive metastasis, recurrence and drug resistance. It has also been reported that EpCAM up-regulation in EAC may lead to an aggressive behavior and, thus, an adverse clinical outcome. Here, we aimed to determine whether treatment with standard chemotherapeutic agents may induce EpCAM expression and, concomitantly, increases in malignant potential and drug resistance in EAC. Methods EpCAM expression was assessed in 20 primary human EAC/adjacent normal tissues, as well as in a human EAC-derived cell line (OE-19), in a pre-malignant Barrett’s Esophagus cell line (Bar-T) and in a benign esophageal cell line (HET 1-A), using immunohistochemistry, Western blotting and qRT-PCR, respectively. Drug-induced resistance was investigated in OE-19-derived spheres treated with (a combination of) adriamycin, cisplatin and 5-fluorouracil (ACF) using survival, adhesion and flow cytometric assays, respectively, and compared to drug resistance induced by standard chemotherapeutic agents (CTA). Finally, ACF treatment-surviving cells were evaluated for their tumor forming capacities both in vitro and in vivo using spheroid formation and xenograft assays, respectively. Results High EpCAM expression was observed in esophageal cancer tissues and esophageal cancer-derived cell lines, but not in adjacent benign esophageal epithelia and benign esophageal cell lines (HET 1-A and Bar-T). The OE-19 cell spheres were drug resistant and EpCAM expression was significantly induced in the OE-19 cell spheres compared to the non-sphere OE-19 cells. When OE-19 cell spheres were challenged with ACF, the EpCAM mRNA and protein levels were further up-regulated up to 48 h, whereas a decreased EpCAM expression was observed at 72 h. EpCAM down-regulation by RNA interference increased the ACF efficacy to kill OE-19 cells. Increased EpCAM expression coincided with the CSC marker CD90 and was associated with an aggressive growth pattern of OE-19 cell spheres in vivo. Conclusions From our data we conclude that an ACF-induced increase in EpCAM expression reflects the selection of a CSC subpopulation that underlies tumor development and drug resistance in EAC.
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Herreros-Pomares A, Aguilar-Gallardo C, Calabuig-Fariñas S, Sirera R, Jantus-Lewintre E, Camps C. EpCAM duality becomes this molecule in a new Dr. Jekyll and Mr. Hyde tale. Crit Rev Oncol Hematol 2018; 126:52-63. [DOI: 10.1016/j.critrevonc.2018.03.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 03/16/2018] [Accepted: 03/17/2018] [Indexed: 02/08/2023] Open
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Tretter JY, Schorpp K, Luxenburger E, Trambauer J, Steiner H, Hadian K, Gires O, Niessing D. A high-content screen for small-molecule regulators of epithelial cell-adhesion molecule (EpCAM) cleavage yields a robust inhibitor. J Biol Chem 2018; 293:8994-9005. [PMID: 29700109 DOI: 10.1074/jbc.ra118.002776] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 04/20/2018] [Indexed: 12/30/2022] Open
Abstract
Epithelial cell-adhesion molecule (EpCAM) is a transmembrane protein that regulates cell cycle progression and differentiation and is overexpressed in many carcinomas. The EpCAM-induced mitogenic cascade is activated via regulated intramembrane proteolysis (RIP) of EpCAM by ADAM and γ-secretases, generating the signaling-active intracellular domain EpICD. Because of its expression pattern and molecular function, EpCAM is a valuable target in prognostic and therapeutic approaches for various carcinomas. So far, several immunotherapeutic strategies have targeted the extracellular domain of EpCAM. However, targeting the intracellular signaling cascade of EpCAM holds promise for specifically interfering with EpCAM's proliferation-stimulating signaling cascade. Here, using a yellow fluorescence protein-tagged version of the C-terminal fragment of EpCAM, we established a high-content screening (HCS) of a small-molecule compound library (n = 27,280) and characterized validated hits that target EpCAM signaling. In total, 128 potential inhibitors were initially identified, of which one compound with robust inhibitory effects on RIP of EpCAM was analyzed in greater detail. In summary, our study demonstrates that the development of an HCS for small-molecule inhibitors of the EpCAM signaling pathway is feasible. We propose that this approach may also be useful for identifying chemical compounds targeting other disorders involving membrane cleavage-dependent signaling pathways.
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Affiliation(s)
| | - Kenji Schorpp
- the Assay Development and Screening Platform, Institute for Molecular Toxicology and Pharmacology, Helmholtz Zentrum München, German Center for Environmental Health, 85764 Neuherberg, Germany
| | - Elke Luxenburger
- the Department of Otorhinolaryngology, Head and Neck Surgery, Grosshadern Medical Center and
| | - Johannes Trambauer
- the Biomedical Center, Metabolic Biochemistry, Ludwig-Maximilians-University Munich, 80539 Munich, Germany
| | - Harald Steiner
- the Biomedical Center, Metabolic Biochemistry, Ludwig-Maximilians-University Munich, 80539 Munich, Germany.,the German Center for Neurodegenerative Diseases, 81377 Munich, Germany, and
| | - Kamyar Hadian
- the Assay Development and Screening Platform, Institute for Molecular Toxicology and Pharmacology, Helmholtz Zentrum München, German Center for Environmental Health, 85764 Neuherberg, Germany
| | - Olivier Gires
- the Department of Otorhinolaryngology, Head and Neck Surgery, Grosshadern Medical Center and
| | - Dierk Niessing
- From the Institute of Structural Biology and .,the Institute of Pharmaceutical Biotechnology, Ulm University, 89081 Ulm, Germany
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Endaya B, Guan SP, Newman JP, Huynh H, Sia KC, Chong ST, Kok CYL, Chung AYF, Liu BB, Hui KM, Lam PYP. Human mesenchymal stem cells preferentially migrate toward highly oncogenic human hepatocellular carcinoma cells with activated EpCAM signaling. Oncotarget 2017; 8:54629-54639. [PMID: 28903370 PMCID: PMC5589609 DOI: 10.18632/oncotarget.17633] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 02/27/2017] [Indexed: 01/16/2023] Open
Abstract
The epithelial cell adhesion molecule (EpCAM) is a type I transmembrane glycoprotein that is regarded as one of the markers for tumor initiating cells (TIC) in human hepatocellular carcinoma (HCC). Much work has been directed towards targeting these TICs as a mean of placing these master regulators of cell proliferation and drug resistance under control. Human bone marrow-derived mesenchymal stem cells are known to exhibit an innate property of tumor tropism. However, the possible relationship between MSC and TIC is not well understood. In this study, we show that MSC migration to HCC can be effectively inhibited by TACE and γ-secretase inhibitors that stop the activation of EpCAM signaling event. Silencing of EpCAM expression through siRNA and antibody approaches also resulted in impaired MSC migration. By contrast, increase levels of EpICD proteins in HCC cells and HCC mouse xenografts resulted in enhanced MSC migration. Taken together, these findings show that MSC is drawn to the more oncogenic population of HCC, and could potentially serve as a cell-based carrier of therapeutic genes to target EpICD-enriched hepatic tumor cells.
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Affiliation(s)
- Berwini Endaya
- Division of Cellular and Molecular Research, National Cancer Centre, Singapore City, Singapore.,Griffith Health Institute, Griffith University, Southport, Australia
| | - Shou P Guan
- Division of Cellular and Molecular Research, National Cancer Centre, Singapore City, Singapore
| | - Jennifer P Newman
- Division of Cellular and Molecular Research, National Cancer Centre, Singapore City, Singapore
| | - Hung Huynh
- Division of Cellular and Molecular Research, National Cancer Centre, Singapore City, Singapore
| | - Kian C Sia
- Division of Cellular and Molecular Research, National Cancer Centre, Singapore City, Singapore
| | - Siao T Chong
- Division of Cellular and Molecular Research, National Cancer Centre, Singapore City, Singapore
| | - Catherine Y L Kok
- Division of Cellular and Molecular Research, National Cancer Centre, Singapore City, Singapore
| | - Alexander Y F Chung
- Department of General Surgery, Singapore General Hospital, Singapore City, Singapore
| | - Bin B Liu
- Liver Cancer Institute of Fudan University, Shanghai, China
| | - Kam M Hui
- Department of Biochemistry, National University of Singapore, Singapore City, Singapore.,Institute of Molecular and Cell Biology, ASTAR, Singapore City, Singapore.,Cancer and Stem Cells Biology Program, Duke-NUS Graduate Medical School, Singapore City, Singapore
| | - Paula Y P Lam
- Division of Cellular and Molecular Research, National Cancer Centre, Singapore City, Singapore.,Department of Physiology, National University of Singapore, Singapore City, Singapore.,Cancer and Stem Cells Biology Program, Duke-NUS Graduate Medical School, Singapore City, Singapore
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