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Wilhelm I, Fazakas C, Molnár J, Haskó J, Végh AG, Cervenak L, Nagyőszi P, Nyúl-Tóth A, Farkas AE, Bauer H, Guillemin GJ, Bauer HC, Váró G, Krizbai IA. Role of Rho/ROCK signaling in the interaction of melanoma cells with the blood-brain barrier. Pigment Cell Melanoma Res 2013; 27:113-23. [PMID: 24148763 DOI: 10.1111/pcmr.12169] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 09/16/2013] [Indexed: 11/28/2022]
Abstract
We have investigated the role of the Rho/ROCK signaling pathway in the interaction of metastatic melanoma cells with the brain endothelium. ROCK inhibition induced a shift of melanoma cells to the mesenchymal phenotype, increased the number of melanoma cells attached to the brain endothelium, and strengthened the adhesion force between melanoma and endothelial cells. Inhibition of ROCK raised the number of melanoma cells migrating through the brain endothelial monolayer and promoted the formation of parenchymal brain metastases in vivo. We have shown that inhibition of the Rho/ROCK pathway in melanoma, but not in brain endothelial cells, is responsible for this phenomenon. Our results indicate that the mesenchymal type of tumor cell movement is primordial in the transmigration of melanoma cells through the blood-brain barrier.
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Affiliation(s)
- Imola Wilhelm
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
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Antelmi E, Cardone RA, Greco MR, Rubino R, Di Sole F, Martino NA, Casavola V, Carcangiu M, Moro L, Reshkin SJ. ß1 integrin binding phosphorylates ezrin at T567 to activate a lipid raft signalsome driving invadopodia activity and invasion. PLoS One 2013; 8:e75113. [PMID: 24086451 PMCID: PMC3782503 DOI: 10.1371/journal.pone.0075113] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Accepted: 08/09/2013] [Indexed: 01/11/2023] Open
Abstract
Extracellular matrix (ECM) degradation is a critical process in tumor cell invasion and requires matrix degrading protrusions called invadopodia. The Na+/H+ exchanger (NHE1) has recently been shown to be fundamental in the regulation of invadopodia actin cytoskeleton dynamics and activity. However, the structural link between the invadopodia cytoskeleton and NHE1 is still unknown. A candidate could be ezrin, a linker between the NHE1 and the actin cytoskeleton known to play a pivotal role in invasion and metastasis. However, the mechanistic basis for its role remains unknown. Here, we demonstrate that ezrin phosphorylated at T567 is highly overexpressed in the membrane of human breast tumors and positively associated with invasive growth and HER2 overexpression. Further, in the metastatic cell line, MDA-MB-231, p-ezrin was almost exclusively expressed in invadopodia lipid rafts where it co-localized in a functional complex with NHE1, EGFR, ß1-integrin and phosphorylated-NHERF1. Manipulation by mutation of ezrins T567 phosphorylation state and/or PIP2 binding capacity or of NHE1s binding to ezrin or PIP2 demonstrated that p-ezrin expression and binding to PIP2 are required for invadopodia-mediated ECM degradation and invasion and identified NHE1 as the membrane protein that p-ezrin regulates to induce invadopodia formation and activity.
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Affiliation(s)
- Ester Antelmi
- Department of Bioscience, Biotechnology and Biopharmacologics, University of Bari, Bari, Italy
- Department of Pathology, Anatomic Pathology A Unit, Istituto Nazionale Tumori, Milan, Italy
| | - Rosa A. Cardone
- Department of Bioscience, Biotechnology and Biopharmacologics, University of Bari, Bari, Italy
| | - Maria R. Greco
- Department of Bioscience, Biotechnology and Biopharmacologics, University of Bari, Bari, Italy
| | - Rosa Rubino
- Department of Bioscience, Biotechnology and Biopharmacologics, University of Bari, Bari, Italy
| | - Francesca Di Sole
- Department of Medicine, University of Maryland School of Medicine and the Medical Service, Department of Veterans Affairs Medical Center, Baltimore, Maryland, United States of America
| | - Nicola A. Martino
- Department of Animal Production, Faculty of Biotechnological Sciences, University of Bari, Bari, Italy
| | - Valeria Casavola
- Department of Bioscience, Biotechnology and Biopharmacologics, University of Bari, Bari, Italy
| | - MariaLuisa Carcangiu
- Department of Pathology, Anatomic Pathology A Unit, Istituto Nazionale Tumori, Milan, Italy
| | - Loredana Moro
- Institute of Biomembranes and Bioenergetics (IBBE), CNR, Bari, Italy
| | - Stephan J. Reshkin
- Department of Bioscience, Biotechnology and Biopharmacologics, University of Bari, Bari, Italy
- * E-mail:
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Chen CH, Thai P, Yoneda K, Adler KB, Yang PC, Wu R. A peptide that inhibits function of Myristoylated Alanine-Rich C Kinase Substrate (MARCKS) reduces lung cancer metastasis. Oncogene 2013; 33:3696-706. [PMID: 23955080 DOI: 10.1038/onc.2013.336] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 07/04/2013] [Accepted: 07/07/2013] [Indexed: 12/25/2022]
Abstract
Myristoylated Alanine-Rich C Kinase Substrate (MARCKS), a substrate of protein kinase C, is a key regulatory molecule controlling mucus granule secretion by airway epithelial cells as well as directed migration of leukocytes, stem cells and fibroblasts. Phosphorylation of MARKCS may be involved in these responses. However, the functionality of MARCKS and its related phosphorylation in lung cancer malignancy have not been characterized. This study demonstrated elevated levels of MARCKS and phospho-MARCKS in highly invasive lung cancer cell lines and lung cancer specimens from non-small-cell lung cancer patients. siRNA knockdown of MARCKS expression in these highly invasive lung cancer cell lines reduced cell migration and suppressed PI3K (phosphatidylinositol 3'-kinase)/Akt phosphorylation and Slug level. Interestingly, treatment with a peptide identical to the MARCKS N-terminus sequence (the MANS peptide) impaired cell migration in vitro and also the metastatic potential of invasive lung cancer cells in vivo. Mechanistically, MANS peptide treatment resulted in a coordination of increase of E-cadherin expression, suppression of MARCKS phosphorylation and AKT/Slug signalling pathway but not the expression of total MARCKS. These results indicate a crucial role for MARCKS, specifically its phosphorylated form, in potentiating lung cancer cell migration/metastasis and suggest a potential use of MARCKS-related peptides in the treatment of lung cancer metastasis.
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Affiliation(s)
- C-H Chen
- Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine and Center for Comparative Respiratory Biology and Medicine, University of California Davis, Davis, CA, USA
| | - P Thai
- Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine and Center for Comparative Respiratory Biology and Medicine, University of California Davis, Davis, CA, USA
| | - K Yoneda
- Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine and Center for Comparative Respiratory Biology and Medicine, University of California Davis, Davis, CA, USA
| | - K B Adler
- Department of Molecular Biomedical Sciences, North Carolina State University, Raleigh, NC, USA
| | - P-C Yang
- Department of Internal Medicine, National Taiwan University College of Medicine, Taipei, Taiwan
| | - R Wu
- Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine and Center for Comparative Respiratory Biology and Medicine, University of California Davis, Davis, CA, USA
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Adada M, Canals D, Hannun YA, Obeid LM. Sphingolipid regulation of ezrin, radixin, and moesin proteins family: implications for cell dynamics. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1841:727-37. [PMID: 23850862 DOI: 10.1016/j.bbalip.2013.07.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 06/30/2013] [Accepted: 07/02/2013] [Indexed: 12/13/2022]
Abstract
A key but poorly studied domain of sphingolipid functions encompasses endocytosis, exocytosis, cellular trafficking, and cell movement. Recently, the ezrin, radixin and moesin (ERM) family of proteins emerged as novel potent targets regulated by sphingolipids. ERMs are structural proteins linking the actin cytoskeleton to the plasma membrane, also forming a scaffold for signaling pathways that are used for cell proliferation, migration and invasion, and cell division. Opposing functions of the bioactive sphingolipid ceramide and sphingosine-1-phosphate (S1P), contribute to ERM regulation. S1P robustly activates whereas ceramide potently deactivates ERM via phosphorylation/dephosphorylation, respectively. This recent dimension of cytoskeletal regulation by sphingolipids opens up new avenues to target cell dynamics, and provides further understanding of some of the unexplained biological effects mediated by sphingolipids. In addition, these studies are providing novel inroads into defining basic mechanisms of regulation and action of bioactive sphingolipids. This review describes the current understanding of sphingolipid regulation of the cytoskeleton, it also describes the biologies in which ERM proteins have been involved, and finally how these two large fields have started to converge. This article is part of a Special Issue entitled New Frontiers in Sphingolipid Biology.
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Affiliation(s)
- Mohamad Adada
- The Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA
| | - Daniel Canals
- The Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA
| | - Yusuf A Hannun
- The Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA
| | - Lina M Obeid
- The Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA; The Northport VA Medical Center, Northport, NY 11768, USA.
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55
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Brown L, Waseem A, Cruz IN, Szary J, Gunic E, Mannan T, Unadkat M, Yang M, Valderrama F, O'Toole EA, Wan H. Desmoglein 3 promotes cancer cell migration and invasion by regulating activator protein 1 and protein kinase C-dependent-Ezrin activation. Oncogene 2013; 33:2363-74. [PMID: 23752190 DOI: 10.1038/onc.2013.186] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Revised: 02/12/2013] [Accepted: 04/04/2013] [Indexed: 12/16/2022]
Abstract
Desmoglein 3 (Dsg3), the pemphigus vulgaris antigen, has recently been shown to be upregulated in squamous cell carcinoma (SCC) and has been identified as a good tumor-specific marker for clinical staging of cervical sentinel lymph nodes in head and neck SCC. However, little is known about its biological function in cancer. The actin-binding protein Ezrin and the activator protein 1 (AP-1) transcription factor are implicated in cancer progression and metastasis. Here, we report that Dsg3 regulates the activity of c-Jun/AP-1 as well as protein kinase C (PKC)-mediated phosphorylation of Ezrin-Thr567, which contributes to the accelerated motility of cancer cells. Ectopic expression of Dsg3 in cancer cell lines caused enhanced phosphorylation at Ezrin-Thr567 with concomitant augmented membrane protrusions, cell spreading and invasive phenotype. We showed that Dsg3 formed a complex with Ezrin at the plasma membrane that was required for its proper function of interacting with F-actin and CD44 as Dsg3 knockdown impaired these associations. The increased Ezrin phosphorylation in Dsg3-overexpressing cells could be abrogated substantially by various pharmacological inhibitors for Ser/Thr kinases, including PKC and Rho kinase that are known to activate Ezrin. Furthermore, a marked increase in c-Jun S63 phosphorylation, among others, was found in Dsg3-overexpressing cells and the activation of c-Jun/AP-1 was further supported by a luciferase reporter assay. Taken together, our study identifies a novel Dsg3-mediated c-Jun/AP-1 regulatory mechanism and PKC-dependent Ezrin phosphorylation that could be responsible for Dsg3-associated cancer metastasis.
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Affiliation(s)
- L Brown
- Queen Mary University of London, Barts and The London School of Medicine and Dentistry, Centre for Clinical and Diagnostic Oral Sciences, Institute of Dentistry, London, UK
| | - A Waseem
- Queen Mary University of London, Barts and The London School of Medicine and Dentistry, Centre for Clinical and Diagnostic Oral Sciences, Institute of Dentistry, London, UK
| | - I N Cruz
- Department of Pharmaceutical and Biological Chemistry, UCL School of Pharmacy, London, UK
| | - J Szary
- Queen Mary University of London, Barts and The London School of Medicine and Dentistry, Centre for Clinical and Diagnostic Oral Sciences, Institute of Dentistry, London, UK
| | - E Gunic
- Queen Mary University of London, Barts and The London School of Medicine and Dentistry, Centre for Clinical and Diagnostic Oral Sciences, Institute of Dentistry, London, UK
| | - T Mannan
- Queen Mary University of London, Barts and The London School of Medicine and Dentistry, Centre for Clinical and Diagnostic Oral Sciences, Institute of Dentistry, London, UK
| | - M Unadkat
- Queen Mary University of London, Barts and The London School of Medicine and Dentistry, Centre for Clinical and Diagnostic Oral Sciences, Institute of Dentistry, London, UK
| | - M Yang
- Department of Pharmaceutical and Biological Chemistry, UCL School of Pharmacy, London, UK
| | - F Valderrama
- Division of Biomedical Sciences, St George's, University of London, Cranmer Terrace, London, UK
| | - E A O'Toole
- Queen Mary University of London, Barts and The London School of Medicine and Dentistry, Centre for Cutaneous Research, Blizard Institute, London, UK
| | - H Wan
- Queen Mary University of London, Barts and The London School of Medicine and Dentistry, Centre for Clinical and Diagnostic Oral Sciences, Institute of Dentistry, London, UK
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Orr Gandy KA, Adada M, Canals D, Carroll B, Roddy P, Hannun YA, Obeid LM. Epidermal growth factor-induced cellular invasion requires sphingosine-1-phosphate/sphingosine-1-phosphate 2 receptor-mediated ezrin activation. FASEB J 2013; 27:3155-66. [PMID: 23629860 DOI: 10.1096/fj.13-228460] [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] [Indexed: 11/11/2022]
Abstract
Ezrin, radixin, and moesin (ERM) proteins link cortical actin to the plasma membrane and coordinate cellular events that require cytoskeletal rearrangement, including cell division, migration, and invasion. While ERM proteins are involved in many important cellular events, the mechanisms regulating their function are not completely understood. Our laboratory previously identified reciprocal roles for the sphingolipids ceramide and sphingosine-1-phosphate (S1P) in the regulation of ERM proteins. We recently showed that ceramide-induced activation of PP1α leads to dephosphorylation and inactivation of ERM proteins, while S1P results in phosphorylation and activation of ERM proteins. Following these findings, we aimed to examine known inducers of the SK/S1P pathway and evaluate their ability to regulate ERM proteins. We examined EGF, a known inducer of the SK/S1P pathway, for its ability to regulate the ERM family of proteins. We found that EGF induces ERM c-terminal threonine phosphorylation via activation of the SK/S1P pathway, as this was prevented by siRNA knockdown or pharmacological inhibition of SK. Using pharmacological, as well as genetic, knockdown approaches, we determined that EGF induces ERM phosphorylation via activation of S1PR2. In addition, EGF led to cell polarization in the form of lamellipodia, and this occurred through a mechanism involving S1PR2-mediated phosphorylation of ezrin T567. EGF-induced cellular invasion was also found to be dependent on S1PR2-induced T567 ezrin phosphorylation, such that S1PR2 antagonist, JTE-013, and expression of a dominant-negative ezrin mutant prevented cellular invasion toward EGF. In this work, a novel mechanism of EGF-stimulated invasion is unveiled, whereby S1P-mediated activation of S1PR2 and phosphorylation of ezrin T567 is required.
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Affiliation(s)
- K Alexa Orr Gandy
- Department of Molecular and Cellular Biology and Pathobiology, Medical University of South Carolina, Charleston, South Carolina, USA
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57
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Sphingosine 1-phosphate induces filopodia formation through S1PR2 activation of ERM proteins. Biochem J 2013; 449:661-72. [PMID: 23106337 DOI: 10.1042/bj20120213] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Previously we demonstrated that the sphingolipids ceramide and S1P (sphingosine 1-phosphate) regulate phosphorylation of the ERM (ezrin/radixin/moesin) family of cytoskeletal proteins [Canals, Jenkins, Roddy, Hernande-Corbacho, Obeid and Hannun (2010) J. Biol. Chem. 285, 32476-3285]. In the present article, we show that exogenously applied or endogenously generated S1P (in a sphingosine kinase-dependent manner) results in significant increases in phosphorylation of ERM proteins as well as filopodia formation. Using phosphomimetic and non-phosphorylatable ezrin mutants, we show that the S1P-induced cytoskeletal protrusions are dependent on ERM phosphorylation. Employing various pharmacological S1PR (S1P receptor) agonists and antagonists, along with siRNA (small interfering RNA) techniques and genetic knockout approaches, we identify the S1PR2 as the specific and necessary receptor to induce phosphorylation of ERM proteins and subsequent filopodia formation. Taken together, the results demonstrate a novel mechanism by which S1P regulates cellular architecture that requires S1PR2 and subsequent phosphorylation of ERM proteins.
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58
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Ezrin overexpression predicts the poor prognosis of gastric adenocarcinoma. Diagn Pathol 2012; 7:135. [PMID: 23039327 PMCID: PMC3502371 DOI: 10.1186/1746-1596-7-135] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Accepted: 09/25/2012] [Indexed: 11/20/2022] Open
Abstract
Background Ezrin is a cytoskeletal protein that is involved in tumor growth and invasion. It has been suggested that Ezrin expression plays an important role in tumor metastasis. This study is aimed to investigate the clinicopathological significance of Ezrin overexpression in gastric adenocarcinomas. Methods Ezrin protein expression was examined by immunohistochemistry in 26 normal gastric mucosa, 32 dysplasia, and 277 gastric adenocarcinomas. The relationship between Ezrin expression and the clinicopathological features of gastric cancers was analyzed. In addition, a gastric cancer cell line, MKN-1, was also used for immunofluorescence staining to evaluate the distribution of Ezrin protein. Results Ezrin protein located in the cytoplasm and/or membrane in the migrating gastric cancer cells, and it mainly concentrated at the protrusion site; however, only cytoplasmic distribution was observed in the non-migrating cancer cells by immunofluorescence staining. The positive rate of Ezrin protein expression was significantly higher in gastric adenocarcinoma and dysplasia compared with that in the normal gastric mucosa. Moreover, expression frequency of Ezrin protein increased significantly in lymph node metastasis and late clinical stages. Consistently, strong expression of Ezrin was significantly correlated with poor prognosis of gastric cancer. Conclusion The detection of Ezrin expression can be used as the marker for early diagnosis and prognosis of gastric adenocarcinoma. Virtual Slides The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2303598677653946
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59
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Lipid raft association restricts CD44-ezrin interaction and promotion of breast cancer cell migration. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 181:2172-87. [PMID: 23031255 DOI: 10.1016/j.ajpath.2012.08.025] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Revised: 08/03/2012] [Accepted: 08/13/2012] [Indexed: 01/13/2023]
Abstract
Cancer cell migration is an early event in metastasis, the main cause of breast cancer-related deaths. Cholesterol-enriched membrane domains called lipid rafts influence the function of many molecules, including the raft-associated protein CD44. We describe a novel mechanism whereby rafts regulate interactions between CD44 and its binding partner ezrin in migrating breast cancer cells. Specifically, in nonmigrating cells, CD44 and ezrin localized to different membranous compartments: CD44 predominantly in rafts, and ezrin in nonraft compartments. After the induction of migration (either nonspecific or CD44-driven), CD44 affiliation with lipid rafts was decreased. This was accompanied by increased coprecipitation of CD44 and active (threonine-phosphorylated) ezrin-radixin-moesin (ERM) proteins in nonraft compartments and increased colocalization of CD44 with the nonraft protein, transferrin receptor. Pharmacological raft disruption using methyl-β-cyclodextrin also increased CD44-ezrin coprecipitation and colocalization, further suggesting that CD44 interacts with ezrin outside rafts during migration. Conversely, promoting CD44 retention inside lipid rafts by pharmacological inhibition of depalmitoylation virtually abolished CD44-ezrin interactions. However, transient single or double knockdown of flotillin-1 or caveolin-1 was not sufficient to increase cell migration over a short time course, suggesting complex crosstalk mechanisms. We propose a new model for CD44-dependent breast cancer cell migration, where CD44 must relocalize outside lipid rafts to drive cell migration. This could have implications for rafts as pharmacological targets to down-regulate cancer cell migration.
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Gallo RM, Khan MA, Shi J, Kapur R, Wei L, Bailey JC, Liu J, Brutkiewicz RR. Regulation of the actin cytoskeleton by Rho kinase controls antigen presentation by CD1d. THE JOURNAL OF IMMUNOLOGY 2012; 189:1689-98. [PMID: 22798677 DOI: 10.4049/jimmunol.1101484] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
CD1d molecules are MHC class I-like molecules that present lipid Ags to NKT cells. Although we have previously shown that several different cell signaling molecules can play a role in the control of Ag presentation by CD1d, a defined mechanism by which a cell signaling pathway regulates CD1d function has been unclear. In the current study, we have found that the Rho kinases, Rho-associated, coiled-coil containing protein kinase (ROCK)1 and ROCK2, negatively regulate both human and mouse CD1d-mediated Ag presentation. Inhibition of ROCK pharmacologically, through specific ROCK1 and ROCK2 short hairpin RNA, or by using dendritic cells generated from ROCK1-deficient mice all resulted in enhanced CD1d-mediated Ag presentation compared with controls. ROCK regulates the actin cytoskeleton by phosphorylating LIM kinase, which, in turn, phosphorylates cofilin, prohibiting actin fiber depolymerization. Treatment of APCs with the actin filament depolymerizing agent, cytochalasin D, as well as knockdown of LIM kinase by short hairpin RNA, resulted in enhanced Ag presentation to NKT cells by CD1d, consistent with our ROCK inhibition data. Therefore, our overall results reveal a model whereby CD1d-mediated Ag presentation is negatively regulated by ROCK via its effects on the actin cytoskeleton.
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Affiliation(s)
- Richard M Gallo
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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Zhou C, Zhong Q, Rhodes LV, Townley I, Bratton MR, Zhang Q, Martin EC, Elliott S, Collins-Burow BM, Burow ME, Wang G. Proteomic analysis of acquired tamoxifen resistance in MCF-7 cells reveals expression signatures associated with enhanced migration. Breast Cancer Res 2012; 14:R45. [PMID: 22417809 PMCID: PMC3446379 DOI: 10.1186/bcr3144] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Revised: 02/14/2012] [Accepted: 03/14/2012] [Indexed: 02/07/2023] Open
Abstract
Introduction Acquired tamoxifen resistance involves complex signaling events that are not yet fully understood. Successful therapeutic intervention to delay the onset of hormone resistance depends critically on mechanistic elucidation of viable molecular targets associated with hormone resistance. This study was undertaken to investigate the global proteomic alterations in a tamoxifen resistant MCF-7 breast cancer cell line obtained by long term treatment of the wild type MCF-7 cell line with 4-hydroxytamoxifen (4-OH Tam). Methods We cultured MCF-7 cells with 4-OH Tam over a period of 12 months to obtain the resistant cell line. A gel-free, quantitative proteomic method was used to identify and quantify the proteome of the resistant cell line. Nano-flow high-performance liquid chromatography coupled to high resolution Fourier transform mass spectrometry was used to analyze fractionated peptide mixtures that were isobarically labeled from the resistant and control cell lysates. Real time quantitative PCR and Western blots were used to verify selected proteomic changes. Lentiviral vector transduction was used to generate MCF-7 cells stably expressing S100P. Online pathway analysis was performed to assess proteomic signatures in tamoxifen resistance. Survival analysis was done to evaluate clinical relevance of altered proteomic expressions. Results Quantitative proteomic analysis revealed a wide breadth of signaling events during transition to acquired tamoxifen resistance. A total of 629 proteins were found significantly changed with 364 up-regulated and 265 down-regulated. Collectively, these changes demonstrated the suppressed state of estrogen receptor (ER) and ER-regulated genes, activated survival signaling and increased migratory capacity of the resistant cell line. The protein S100P was found to play a critical role in conferring tamoxifen resistance and enhanced cell motility. Conclusions Our data demonstrate that the adaptive changes in the proteome of tamoxifen resistant breast cancer cells are characterized by down-regulated ER signaling, activation of alternative survival pathways, and enhanced cell motility through regulation of the actin cytoskeleton dynamics. Evidence also emerged that S100P mediates acquired tamoxifen resistance and migration capacity.
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Affiliation(s)
- Changhua Zhou
- Department of Chemistry, Xavier University of Louisiana, 1 Drexel Drive, New Orleans, LA 70125, USA
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Tan O, Ornek T, Fadiel A, Carrick KS, Arici A, Doody K, Carr BR, Naftolin F. Expression and activation of the membrane-cytoskeleton protein ezrin during the normal endometrial cycle. Fertil Steril 2012; 97:192-9.e2. [PMID: 22192140 DOI: 10.1016/j.fertnstert.2011.10.039] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Revised: 10/24/2011] [Accepted: 10/31/2011] [Indexed: 01/07/2023]
Abstract
OBJECTIVE To examine total ezrin expression (ezrin and phospho-ezrin) through the normal endometrial cycle and to correlate ezrin activation and localization with cytologic changes. DESIGN Experimental laboratory study. SETTING University medical centers. PATIENT(S) Reproductive-age women. INTERVENTION(S) A total of 36 samples of normal early, mid-, and late proliferative- and secretory-phase endometrium were studied for immunoreactive total ezrin (ir-T-ezrin) and phospho-ezrin (ir-p-ezrin) expression by histology, immunohistochemistry, and Western blotting. MAIN OUTCOME MEASURE(S) Total ezrin and phospho-ezrin expressions through the normal endometrial cycle. RESULT(S) Throughout the cycle ir-T-ezrin is present in the epithelium. The intensity and localization of both ir-ezrin and ir-p-ezrin vary greatly throughout the cycle. The main findings include the following: lateral localization of ir-ezrin/ir-p-ezrin in association with membrane specializations; dense staining around secretory vacuoles (secretory phase); dense staining of the apical surfaces, including microvilli and pinopodes of epithelial cells, especially during the mid- to late secretory phases; and the presence of ezrin in the glandular secretions. Immunoreactive total ezrin and ir-p-ezrin were not expressed by stromal fibroblasts. CONCLUSION(S) Ezrin is a prominent protein in the cycling endometrium. The most striking findings were the gravitation of ir-ezrin/ir-p-ezrin to the periphery of secretory vacuoles, localization on apical surfaces of the luminal epithelium, dense ezrin staining in secretory-phase epithelial cell plumes, and the presence of ir-ezrin/ir-p-ezrin in secretory-phase luminal secretions. These findings may have functional implications, especially for implantation biology.
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Affiliation(s)
- Orkun Tan
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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