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Alfonso A, Vieytes MR, Botana LM. Yessotoxin, a Promising Therapeutic Tool. Mar Drugs 2016; 14:md14020030. [PMID: 26828502 PMCID: PMC4771983 DOI: 10.3390/md14020030] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 01/15/2016] [Accepted: 01/18/2016] [Indexed: 02/05/2023] Open
Abstract
Yessotoxin (YTX) is a polyether compound produced by dinoflagellates and accumulated in filter feeding shellfish. No records about human intoxications induced by this compound have been published, however it is considered a toxin. Modifications in second messenger levels, protein levels, immune cells, cytoskeleton or activation of different cellular death types have been published as consequence of YTX exposure. This review summarizes the main intracellular pathways modulated by YTX and their pharmacological and therapeutic implications.
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Affiliation(s)
- Amparo Alfonso
- Department of Pharmacology, Faculty of Veterinary, University of Santiago of Compostela, 27002 Lugo, Spain.
| | - Mercedes R Vieytes
- Department of Physiology, Faculty of Veterinary, University of Santiago of Compostela, 27002 Lugo, Spain.
| | - Luis M Botana
- Department of Physiology, Faculty of Veterinary, University of Santiago of Compostela, 27002 Lugo, Spain.
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2
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Abstract
The arrival of multicellularity in evolution facilitated cell-cell signaling in conjunction with adhesion. As the ectodomains of cadherins interact with each other directly in trans (as well as in cis), spanning the plasma membrane and associating with multiple other entities, cadherins enable the transduction of "outside-in" or "inside-out" signals. We focus this review on signals that originate from the larger family of cadherins that are inwardly directed to the nucleus, and thus have roles in gene control or nuclear structure-function. The nature of cadherin complexes varies considerably depending on the type of cadherin and its context, and we will address some of these variables for classical cadherins versus other family members. Substantial but still fragmentary progress has been made in understanding the signaling mediators used by varied cadherin complexes to coordinate the state of cell-cell adhesion with gene expression. Evidence that cadherin intracellular binding partners also localize to the nucleus is a major point of interest. In some models, catenins show reduced binding to cadherin cytoplasmic tails favoring their engagement in gene control. When bound, cadherins may serve as stoichiometric competitors of nuclear signals. Cadherins also directly or indirectly affect numerous signaling pathways (e.g., Wnt, receptor tyrosine kinase, Hippo, NFκB, and JAK/STAT), enabling cell-cell contacts to touch upon multiple biological outcomes in embryonic development and tissue homeostasis.
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Affiliation(s)
- Pierre D McCrea
- Department of Genetics, University of Texas MD Anderson Cancer Center; Program in Genes & Development, Graduate School in Biomedical Sciences, Houston, Texas, USA.
| | - Meghan T Maher
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Cara J Gottardi
- Cellular and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA; Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.
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3
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Nava P, Kamekura R, Nusrat A. Cleavage of transmembrane junction proteins and their role in regulating epithelial homeostasis. Tissue Barriers 2014; 1:e24783. [PMID: 24665393 PMCID: PMC3879235 DOI: 10.4161/tisb.24783] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 04/19/2013] [Accepted: 04/23/2013] [Indexed: 02/07/2023] Open
Abstract
Epithelial tissues form a selective barrier that separates the external environment from the internal tissue milieu. Single epithelial cells are densely packed and associate via distinct intercellular junctions. Intercellular junction proteins not only control barrier properties of the epithelium but also play an important role in regulating epithelial homeostasis that encompasses cell proliferation, migration, differentiation and regulated shedding. Recent studies have revealed that several proteases target epithelial junction proteins during physiological maturation as well as in pathologic states such as inflammation and cancer. This review discusses mechanisms and biological consequences of transmembrane junction protein cleavage. The influence of junction protein cleavage products on pathogenesis of inflammation and cancer is discussed.
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Affiliation(s)
- Porfirio Nava
- Epithelial Pathobiology and Mucosal Inflammation Research Unit; Department of Pathology and Laboratory Medicine; Emory University School of Medicine; Atlanta, GA USA ; Department of Physiology; Biophysics and Neurosciences; Center for Research and Advanced Studies of the National Polytechnic Institute (CINVESTAV); México DF, Mexico
| | - Ryuta Kamekura
- Epithelial Pathobiology and Mucosal Inflammation Research Unit; Department of Pathology and Laboratory Medicine; Emory University School of Medicine; Atlanta, GA USA
| | - Asma Nusrat
- Epithelial Pathobiology and Mucosal Inflammation Research Unit; Department of Pathology and Laboratory Medicine; Emory University School of Medicine; Atlanta, GA USA
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4
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Bozym RA, Patel K, White C, Cheung KH, Bergelson JM, Morosky SA, Coyne CB. Calcium signals and calpain-dependent necrosis are essential for release of coxsackievirus B from polarized intestinal epithelial cells. Mol Biol Cell 2011; 22:3010-21. [PMID: 21737691 PMCID: PMC3164450 DOI: 10.1091/mbc.e11-02-0094] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 06/10/2011] [Accepted: 06/21/2011] [Indexed: 12/30/2022] Open
Abstract
Coxsackievirus B (CVB), a member of the enterovirus family, targets the polarized epithelial cells lining the intestinal tract early in infection. Although the polarized epithelium functions as a protective barrier, this barrier is likely exploited by CVB to promote viral entry and subsequent egress. Here we show that, in contrast to nonpolarized cells, CVB-infected polarized intestinal Caco-2 cells undergo nonapoptotic necrotic cell death triggered by inositol 1,4,5-trisphosphate receptor-dependent calcium release. We further show that CVB-induced cellular necrosis depends on the Ca(2+)-activated protease calpain-2 and that this protease is involved in CVB-induced disruption of the junctional complex and rearrangements of the actin cytoskeleton. Our study illustrates the cell signaling pathways hijacked by CVB, and perhaps other viral pathogens, to promote their replication and spread in polarized cell types.
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Affiliation(s)
- Rebecca A. Bozym
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219
| | - Kunal Patel
- Division of Infectious Diseases, Children's Hospital of Philadelphia, Philadelphia, PA 19104
| | - Carl White
- Department of Physiology & Biophysics, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064
| | - King-Ho Cheung
- Department of Physiology, University of Hong Kong, Hong Kong
| | - Jeffrey M. Bergelson
- Division of Infectious Diseases, Children's Hospital of Philadelphia, Philadelphia, PA 19104
| | - Stefanie A. Morosky
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219
| | - Carolyn B. Coyne
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219
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5
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Khamis ZI, Iczkowski KA, Sang QXA. Metastasis suppressors in human benign prostate, intraepithelial neoplasia, and invasive cancer: their prospects as therapeutic agents. Med Res Rev 2011; 32:1026-77. [PMID: 22886631 DOI: 10.1002/med.20232] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Despite advances in diagnosis and treatment of prostate cancer, development of metastases remains a major clinical challenge. Research efforts are dedicated to overcome this problem by understanding the molecular basis of the transition from benign cells to prostatic intraepithelial neoplasia (PIN), localized carcinoma, and metastatic cancer. Identification of proteins that inhibit dissemination of cancer cells will provide new perspectives to define novel therapeutics. Development of antimetastatic drugs that trigger or mimic the effect of metastasis suppressors represents new therapeutic approaches to improve patient survival. This review focuses on different biochemical and cellular functions of metastasis suppressors known to play a role in prostate carcinogenesis and progression. Ten putative metastasis suppressors implicated in prostate cancer are discussed. CD44s is decreased in both PIN and cancer; Drg-1, E-cadherin, KAI-1, RKIP, and SSeCKS show similar expression between benign epithelia and PIN, but are downregulated in invasive cancer; whereas, maspin, MKK4, Nm23 and PTEN are upregulated in PIN and downregulated in cancer. Moreover, the potential role of microRNA in prostate cancer progression, the understanding of the cellular distribution and localization of metastasis suppressors, their mechanism of action, their effect on prostate invasion and metastasis, and their potential use as therapeutics are addressed.
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Affiliation(s)
- Zahraa I Khamis
- Department of Chemistry and Biochemistry and Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306-4390, USA
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Sumitomo T, Nakata M, Higashino M, Jin Y, Terao Y, Fujinaga Y, Kawabata S. Streptolysin S contributes to group A streptococcal translocation across an epithelial barrier. J Biol Chem 2010; 286:2750-61. [PMID: 21084306 DOI: 10.1074/jbc.m110.171504] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Group A Streptococcus pyogenes (GAS) is a human pathogen that causes local suppurative infections and severe invasive diseases. Systemic dissemination of GAS is initiated by bacterial penetration of the epithelial barrier of the pharynx or damaged skin. To gain insight into the mechanism by which GAS penetrates the epithelial barrier, we sought to identify both bacterial and host factors involved in the process. Screening of a transposon mutant library of a clinical GAS isolate recovered from an invasive episode allowed identification of streptolysin S (SLS) as a novel factor that facilitates the translocation of GAS. Of note, the wild type strain efficiently translocated across the epithelial monolayer, accompanied by a decrease in transepithelial electrical resistance and cleavage of transmembrane junctional proteins, including occludin and E-cadherin. Loss of integrity of intercellular junctions was inhibited after infection with a deletion mutant of the sagA gene encoding SLS, as compared with those infected with the wild type strain. Interestingly, following GAS infection, calpain was recruited to the plasma membrane along with E-cadherin. Moreover, bacterial translocation and destabilization of the junctions were partially inhibited by a pharmacological calpain inhibitor or genetic interference with calpain. Our data indicate a potential function of SLS that facilitates GAS invasion into deeper tissues via degradation of epithelial intercellular junctions in concert with the host cysteine protease calpain.
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Affiliation(s)
- Tomoko Sumitomo
- Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan
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Weber H, Hühns S, Lüthen F, Jonas L. Calpain-mediated breakdown of cytoskeletal proteins contributes to cholecystokinin-induced damage of rat pancreatic acini. Int J Exp Pathol 2009; 90:387-99. [PMID: 19659897 PMCID: PMC2741149 DOI: 10.1111/j.1365-2613.2009.00638.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Accepted: 11/30/2008] [Indexed: 12/01/2022] Open
Abstract
The cytosolic cysteine protease calpain is implicated in a multitude of cellular functions but also plays a role in cell damage. Our previous results suggest that an activation of calpain accompanied by a decrease in its endogenous inhibitor calpastatin may contribute to pancreatic damage during cerulein-induced acute pancreatitis. The present study aimed at the time course of secretagogue-induced calpain activation and cellular substrates of the protease. Isolated rat pancreatic acini were incubated with a supramaximal concentration of cholecystokinin (0.1 microM CCK) for 30 min in the presence or absence of the calpain inhibitor Z-Val-Phe methyl ester (100 microM ZVP). The activation of calpain and the expression of calpastatin and the actin cytoskeleton-associated proteins alphaII-spectrin, E-cadherin and vinculin were studied by immunoblotting. The cell damage was assessed by lactate dehydrogenase release and ultrastructural analysis including fluorescence-labelled actin filaments. Immediately after administration, CCK led to activation of both calpain isoforms, mu- and m-calpain. The protease activation was accompanied by a decrease in the E-cadherin level and formation of calpain-specific breakdown products of alphaII-spectrin. A calpain-specific cleavage product of vinculin appeared concomitantly with changes in the actin filament organization. No effect of CCK on calpastatin was found. Inhibition of calpain by ZVP reduced CCK-induced damage of the actin-associated proteins and the cellular ultrastructure including the actin cytoskeleton. The results suggest that CCK-induced acinar cell damage requires activation of calpain and that the actin cytoskeleton belongs to the cellular targets of the protease.
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Affiliation(s)
- Heike Weber
- Institute of Clinical Chemistry and Laboratory Medicine, University of Rostock, D-18057 Rostock, Germany.
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8
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Abstract
Neural-cadherin (N-cadherin), a member of the classical cadherin family of transmembrane glycoproteins, mediates cellular recognition and cell-cell adhesion through calcium-dependent homophilic interactions and plays important roles in the development and maintenance of the nervous system. Metalloproteinase is known to cleave N-cadherin, which is further cleaved by gamma-secretase. The intracellular domain of N-cadherin interacts with beta-catenin, and beta-catenin stability is critical for cell-cell adhesion and cell survival. In the present study, we showed that N-cadherin is cleaved specifically by calpain, resulting in the generation of a novel 110 kDa fragment. The cleavage occurred in ischemic brain lesions and in vitro neural cells in the presence of NMDA and ionomycin, and was restored by calpain inhibitors but not matrix metalloproteinase or gamma-secretase inhibitors. Calpain directly cleaved N-cadherin in in vitro calpain assays, and calpain inhibitors prevented its cleavage in a dose-dependent manner. Using N-cadherin deletion mutants, we found that calpain cleavage sites exist in at least four regions of the cytoplasmic domain. Treatment with NMDA induced neuronal death, and it suppressed the expression of surface N-cadherin and the N-cadherin/beta-catenin interaction, effects that were prevented by calpain inhibitor. Furthermore, calpain-mediated N-cadherin cleavage significantly affected cell-cell adhesion, AKT signaling, the N-cadherin/beta-catenin interaction and the Wnt target gene expressions through the accumulation of nuclear beta-catenin.
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9
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Chun J, Prince A. TLR2-induced calpain cleavage of epithelial junctional proteins facilitates leukocyte transmigration. Cell Host Microbe 2009; 5:47-58. [PMID: 19154987 DOI: 10.1016/j.chom.2008.11.009] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2008] [Revised: 10/09/2008] [Accepted: 11/04/2008] [Indexed: 11/26/2022]
Abstract
Recruitment of polymorphonuclear leukocytes (PMNs) into the lungs in response to inhaled pathogens is initiated by epithelial signaling, the activation of toll-like receptors (TLRs), and the production of the chemokine interleukin-8. To reach the site of infection, PMNs must be mobilized through epithelial junctions. Here, we demonstrate that Ca(2+) fluxes generated by TLR2 signals activate calpains, Ca(2+)-dependent cysteine proteases. These activated calpains cleave the transmembrane junctional proteins occludin and E-cadherin without breaching the integrity of the epithelial barrier. Calpain inhibitors decrease PMN transepithelial migration in response to TLR2 agonists both in vitro and in a mouse model of P. aeruginosa infection. Thus, TLR2 signaling in the airway not only induces chemokine expression to recruit PMNs, but also initiates cleavage of junctional proteins to accommodate transmigration of the recruited PMNs.
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Affiliation(s)
- Jarin Chun
- Department of Pharmacology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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10
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Nava P, Laukoetter MG, Hopkins AM, Laur O, Gerner-Smidt K, Green KJ, Parkos CA, Nusrat A. Desmoglein-2: a novel regulator of apoptosis in the intestinal epithelium. Mol Biol Cell 2007; 18:4565-78. [PMID: 17804817 PMCID: PMC2043542 DOI: 10.1091/mbc.e07-05-0426] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2007] [Revised: 07/19/2007] [Accepted: 08/27/2007] [Indexed: 11/11/2022] Open
Abstract
Intestinal epithelial intercellular junctions regulate barrier properties, and they have been linked to epithelial differentiation and programmed cell death (apoptosis). However, mechanisms regulating these processes are poorly defined. Desmosomes are critical elements of intercellular junctions; they are punctate structures made up of transmembrane desmosomal cadherins termed desmoglein-2 (Dsg2) and desmocollin-2 (Dsc2) that affiliate with the underlying intermediate filaments via linker proteins to provide mechanical strength to epithelia. In the present study, we generated an antibody, AH12.2, that recognizes Dsg2. We show that Dsg2 but not another desmosomal cadherin, Dsc2, is cleaved by cysteine proteases during the onset of intestinal epithelial cell (IEC) apoptosis. Small interfering RNA-mediated down-regulation of Dsg2 protected epithelial cells from apoptosis. Moreover, we report that a C-terminal fragment of Dsg2 regulates apoptosis and Dsg2 protein levels. Our studies highlight a novel mechanism by which Dsg2 regulates IEC apoptosis driven by cysteine proteases during physiological differentiation and inflammation.
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Affiliation(s)
- Porfirio Nava
- *Epithelial Pathobiology Research Unit, Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA 30322
| | - Mike G. Laukoetter
- *Epithelial Pathobiology Research Unit, Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA 30322
- Department of General Surgery, University of Muenster, D-48149 Muenster, Germany
| | - Ann M. Hopkins
- UCD School of Medicine and Medical Science, University College, Dublin 4, Ireland; and
| | - Oskar Laur
- *Epithelial Pathobiology Research Unit, Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA 30322
| | - Kirsten Gerner-Smidt
- *Epithelial Pathobiology Research Unit, Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA 30322
| | - Kathleen J. Green
- Northwestern University Feinberg School of Medicine, Chicago, IL 60611
| | - Charles A. Parkos
- *Epithelial Pathobiology Research Unit, Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA 30322
| | - Asma Nusrat
- *Epithelial Pathobiology Research Unit, Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA 30322
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Haga T, Uchide N, Tugizov S, Palefsky JM. Role of E-cadherin in the induction of apoptosis of HPV16-positive CaSki cervical cancer cells during multicellular tumor spheroid formation. Apoptosis 2007; 13:97-108. [PMID: 17906929 DOI: 10.1007/s10495-007-0132-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Multicellular tumor spheroids (MCTS) are three dimensional cell culture systems induced by suspension culture. MCTS are widely used in cancer research because of their similarity to solid tumors. CaSki cells are derived from a metastatic cervical cancer containing human papillomavirus 16 (HPV16). Cell death of CaSki cells in MCTS has been previously reported, and our model is used to better characterize the mechanisms of cell death of HPV16-positive keratinocytes. In this study, we found that apoptosis of CaSki cells was induced by suspension culture along with the formation of MCTS after 24 h of incubation. In suspended CaSki cells, monoclonal antibodies blocking E-cadherin function inhibited MCTS formation and suppressed suspension-induced apoptosis in a dose-dependent manner. Western blot for E-cadherin detected upregulation of the authentic 120 kDa band from MCTS of CaSki cells as well as a shorter 100 kDa band. Addition of EGF, whose receptor is known to form a complex with E-cadherin, abrogated apoptosis of suspended CaSki cells in a dose-dependent manner. These findings suggest that E-cadherin-dependent cell-cell contact, directly or indirectly, mediates the signal to undergo apoptosis of CaSki cells during MCTS formation, and thus provides new information on the role of E-cadherin in cervical cancer cell apoptosis.
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Affiliation(s)
- Takeshi Haga
- Department of Veterinary Microbiology, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki, Japan.
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Kuefer R, Day KC, Kleer CG, Sabel MS, Hofer MD, Varambally S, Zorn CS, Chinnaiyan AM, Rubin MA, Day ML. ADAM15 disintegrin is associated with aggressive prostate and breast cancer disease. Neoplasia 2006; 8:319-29. [PMID: 16756724 PMCID: PMC1600681 DOI: 10.1593/neo.05682] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The aim of the current study was to evaluate the expression of ADAM15 disintegrin (ADAM15) in a broad spectrum of human tumors. The transcript for ADAM15 was found to be highly upregulated in a variety of tumor cDNA expression arrays. ADAM15 protein expression was examined in tissue microarrays (TMAs) consisting of 638 tissue cores. TMA analysis revealed that ADAM15 protein was significantly increased in multiple types of adenocarcinoma, specifically in prostate and breast cancer specimens. Statistical association was observed with disease progression within clinical parameters of predictive outcome for both prostate and breast cancers, pertaining to Gleason sum and angioinvasion, respectively. In this report, we also present data from a cDNA microarray of prostate cancer (PCa), where we compared transfected LNCaP cells that overexpress ADAM15 to vector control cells. In these experiments, we found that ADAM15 expression was associated with the induction of specific proteases and protease inhibitors, particularly tissue inhibitor of metalloproteinase 2, as validated in a separate PCa TMA. These results suggest that ADAM15 is generally overexpressed in adenocarcinoma and is highly associated with metastatic progression of prostate and breast cancers.
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Affiliation(s)
- Rainer Kuefer
- Department of Urology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109-0944, USA
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Zhang X, Emerald BS, Mukhina S, Mohankumar KM, Kraemer A, Yap AS, Gluckman PD, Lee KO, Lobie PE. HOXA1 is required for E-cadherin-dependent anchorage-independent survival of human mammary carcinoma cells. J Biol Chem 2005; 281:6471-81. [PMID: 16373333 DOI: 10.1074/jbc.m512666200] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Forced expression of HOXA1 is sufficient to stimulate oncogenic transformation of immortalized human mammary epithelial cells and subsequent tumor formation. We report here that the expression and transcriptional activity of HOXA1 are increased in mammary carcinoma cells at full confluence. This confluence-dependent expression of HOXA1 was abrogated by incubation of cells with EGTA to produce loss of intercellular contact and rescued by extracellular addition of Ca2+. Increased HOXA1 expression at full confluence was prevented by an E-cadherin function-blocking antibody and attachment of non-confluent cells to a substrate by homophilic ligation of E-cadherin increased HOXA1 expression. E-cadherin-directed signaling increased HOXA1 expression through Rac1. Increased HOXA1 expression consequent to E-cadherin-activated signaling decreased apoptotic cell death and was required for E-cadherin-dependent anchorage-independent proliferation of human mammary carcinoma cells. HOXA1 is therefore a downstream effector of E-cadherin-directed signaling required for anchorage-independent proliferation of mammary carcinoma cells.
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Affiliation(s)
- Xin Zhang
- Department of Medicine and Institute of Molecular and Cell Biology, National University of Singapore, 30 Medical Dr., Singapore 117609, Republic of Singapore
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14
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Benetti R, Copetti T, Dell'Orso S, Melloni E, Brancolini C, Monte M, Schneider C. The calpain system is involved in the constitutive regulation of beta-catenin signaling functions. J Biol Chem 2005; 280:22070-80. [PMID: 15817486 DOI: 10.1074/jbc.m501810200] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Beta-catenin is a multifunctional protein serving both as a structural element in cell adhesion and as a signaling component in the Wnt pathway, regulating embryogenesis and tumorigenesis. The signaling fraction of beta-catenin is tightly controlled by the adenomatous polyposis coli-axin-glycogen synthase kinase 3beta complex, which targets it for proteasomal degradation. It has been recently shown that Ca(2+) release from internal stores results in nuclear export and calpain-mediated degradation of beta-catenin in the cytoplasm. Here we have highlighted the critical relevance of constitutive calpain pathway in the control of beta-catenin levels and functions, showing that small interference RNA knock down of endogenous calpain per se (i.e. in the absence of external stimuli) induces an increase in the free transcriptional competent pool of endogenous beta-catenin. We further characterized the role of the known calpain inhibitors, Gas2 and Calpastatin, demonstrating that they can also control levels, function, and localization of beta-catenin through endogenous calpain regulation. Finally we present Gas2 dominant negative (Gas2DN) as a new tool for regulating calpain activity, providing evidence that it counteracts the described effects of both Gas2 and Calpastatin on beta-catenin and that it works via calpain independently of the classical glycogen synthase kinase 3beta and proteasome pathway. Moreover, we provide in vitro biochemical evidence showing that Gas2DN can increase the activity of calpain and that in vivo it can induce degradation of stabilized/mutated beta-catenin. In fact, in a context where the classical proteasome pathway is impaired, as in colon cancer cells, Gas2DN biological effects accounted for a significant reduction in proliferation and anchorage-independent growth of colon cancer.
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Affiliation(s)
- Roberta Benetti
- Laboratorio Nazionale del Consorzio Interuniversitario per le Biotecnologie, Area Science Park, Padriciano 99, 34012 Trieste, Italy
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