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Wang J, Jia Y, Wang L, Li D, Wang L, Zhu Y, Liu J, Gong J. Vasodilator-Stimulated Phosphoprotein: Regulators of Adipokines Resistin and Phenotype Conversion of Epicardial Adipocytes. Med Sci Monit 2018; 24:6010-6020. [PMID: 30156215 PMCID: PMC6126413 DOI: 10.12659/msm.908111] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Background Endothelial dysfunction plays a central part in the pathogenesis of coronary atherosclerosis. The adipokine resistin is one of the key players in endothelial cell dysfunction. In addition, the role of epicardial fat in coronary artery endothelial dysfunction is also emphasized. We investigated whether vasodilator-stimulated phosphoprotein (VASP) is involved in resistin-related endothelial dysfunction and the phenotype conversion of epicardial adipocytes. Material/Methods Cell proliferation and migration were evaluated by MTT and Transwell chamber assay, respectively. Next, we took epicardial fat samples from patients with valvular heart disease and non-coronary artery disease. Gene expression was determined by reverse transcription-quantitative polymerase chain reaction and relative abundance of the protein by Western blotting. Results Resistin induced endothelial proliferation and migration in a dose-dependent manner. Both resistin-induced cell proliferation and migration were effectively blocked by ablation of VASP. The brown adipose tissue-specific genes for uncoupling protein 1 (UCP-1) and PR-domain-missing16 (PRDM16) decreased, but the white adipose tissue-specific genes for resistin and RIP140 increased in VASP-deficient adipocytes compared with the LV-sicntr group. However, disruption of the Ras homolog gene family member A (RhoA) /Rho-associated kinase (ROCK) in VASP-deficient adipocytes with specific inhibitors inverted the adipocyte phenotype existing in VASP-deficient adipocytes. Furthermore, the expressions of proinflammatory cytokines interleukin-6 (IL-6), interleukin-8 (IL-8), and monocyte chemoattractantprotein-1 (MCP-1) in VASP-deficient adipocytes were markedly upregulated compared with the LV-sicntr group. Conclusions These results suggest a physiological role for VASP in coronary atherosclerosis through regulating adipokine resistin and phenotype conversion of epicardial adipose tissue.
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Affiliation(s)
- Jing Wang
- Department of Cardiology, Jinling Hospital, School of Clinical Medicine, Nanjing University, Nanjing, Jiangsu, China (mainland)
| | - Yan Jia
- Department of Cardiology, Jinling Hospital, School of Clinical Medicine, Nanjing University, Nanjing, Jiangsu, China (mainland)
| | - Lijun Wang
- Department of Cardiology, Jinling Hospital, School of Clinical Medicine, Nanjing University, Nanjing, Jiangsu, China (mainland)
| | - Demin Li
- Department of Cardiothoracic Surgery, Jinling Hospital, School of Clinical Medicine, Nanjing University, Nanjing, Jiangsu, China (mainland)
| | - Lei Wang
- Department of Cardiology, Jinling Hospital, School of Clinical Medicine, Nanjing University, Nanjing, Jiangsu, China (mainland)
| | - Ying Zhu
- Department of Cardiology, Jinling Hospital, School of Clinical Medicine, Nanjing University, Nanjing, Jiangsu, China (mainland)
| | - Jing Liu
- Department of Cardiology, Jinling Hospital, School of Clinical Medicine, Nanjing University, Nanjing, Jiangsu, China (mainland)
| | - Jianbin Gong
- Department of Cardiology, Jinling Hospital, School of Clinical Medicine, Nanjing University, Nanjing, Jiangsu, China (mainland)
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2
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Lai YJ, Tsai JC, Tseng YT, Wu MS, Liu WS, Lam HI, Yu JH, Nozell SE, Benveniste EN. Small G protein Rac GTPases regulate the maintenance of glioblastoma stem-like cells in vitro and in vivo. Oncotarget 2017; 8:18031-18049. [PMID: 28160553 PMCID: PMC5392305 DOI: 10.18632/oncotarget.14949] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 01/03/2017] [Indexed: 12/31/2022] Open
Abstract
Glioblastoma is the most common and aggressive malignant brain tumor in adults. The existence of glioblastoma stem cells (GSCs) or stem-like cells (stemloids) may account for its invasiveness and high recurrence. Rac proteins belong to the Rho small GTPase subfamily which regulates cell movement, proliferation, and survival. To investigate whether Rac proteins can serve as therapeutic targets for glioblastoma, especially for GSCs or stemloids, we examined the potential roles of Rac1, Rac2 and Rac3 on the properties of tumorspheres derived from glioblastoma cell lines. Tumorspheres are thought to be glioblastoma stem-like cells. We showed that Rac proteins promote the STAT3 and ERK activation and enhance cell proliferation and colony formation of glioblastoma stem-like cells. Knockdown of Rac proteins reduces the expression of GSC markers, such as CD133 and Sox2. The in vivo effects of Rac proteins in glioblastoma were further studied in zebrafish and in the mouse xenotransplantation model. Knocking-down Rac proteins abolished the angiogenesis effect induced by the injected tumorspheres in zebrafish model. In the CD133+-U373-tumorsphere xenotransplanted mouse model, suppression of Rac proteins decreased the incidence of tumor formation and inhibited the tumor growth. Moreover, knockdown of Rac proteins reduced the sphere forming efficiency of cells derived from these tumors. In conclusion, not only Rac1 but also Rac2 and 3 are important for glioblastoma tumorigenesis and can serve as the potential therapeutic targets against glioblastoma and its stem-like cells.
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Affiliation(s)
- Yun-Ju Lai
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Jui-Cheng Tsai
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Ying-Ting Tseng
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Meng-Shih Wu
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Wen-Shan Liu
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Hoi-Ian Lam
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Jei-Hwa Yu
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, AL, USA
| | - Susan E Nozell
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, AL, USA
| | - Etty N Benveniste
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, AL, USA
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3
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Tumor Cell Invadopodia: Invasive Protrusions that Orchestrate Metastasis. Trends Cell Biol 2017; 27:595-607. [PMID: 28412099 DOI: 10.1016/j.tcb.2017.03.003] [Citation(s) in RCA: 246] [Impact Index Per Article: 35.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 03/09/2017] [Accepted: 03/13/2017] [Indexed: 12/26/2022]
Abstract
Invadopodia are a subset of invadosomes that are implicated in the integration of signals from the tumor microenvironment to support tumor cell invasion and dissemination. Recent progress has begun to define how tumor cells regulate the plasticity necessary for invadopodia to assemble and function efficiently in the different microenvironments encountered during dissemination in vivo. Exquisite mapping by many laboratories of the pathways involved in integrating diverse invadopodium initiation signals, from growth factors, to extracellular matrix (ECM) and cell-cell contact in the tumor microenvironment, has led to insight into the molecular basis of this plasticity. Here, we integrate this new information to discuss how the invadopodium is an important conductor that orchestrates tumor cell dissemination during metastasis.
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Sakuma C, Saito Y, Umehara T, Kamimura K, Maeda N, Mosca TJ, Miura M, Chihara T. The Strip-Hippo Pathway Regulates Synaptic Terminal Formation by Modulating Actin Organization at the Drosophila Neuromuscular Synapses. Cell Rep 2016; 16:2289-97. [PMID: 27545887 DOI: 10.1016/j.celrep.2016.07.066] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 06/05/2016] [Accepted: 07/25/2016] [Indexed: 12/19/2022] Open
Abstract
Synapse formation requires the precise coordination of axon elongation, cytoskeletal stability, and diverse modes of cell signaling. The underlying mechanisms of this interplay, however, remain unclear. Here, we demonstrate that Strip, a component of the striatin-interacting phosphatase and kinase (STRIPAK) complex that regulates these processes, is required to ensure the proper development of synaptic boutons at the Drosophila neuromuscular junction. In doing so, Strip negatively regulates the activity of the Hippo (Hpo) pathway, an evolutionarily conserved regulator of organ size whose role in synapse formation is currently unappreciated. Strip functions genetically with Enabled, an actin assembly/elongation factor and the presumptive downstream target of Hpo signaling, to modulate local actin organization at synaptic termini. This regulation occurs independently of the transcriptional co-activator Yorkie, the canonical downstream target of the Hpo pathway. Our study identifies a previously unanticipated role of the Strip-Hippo pathway in synaptic development, linking cell signaling to actin organization.
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Affiliation(s)
- Chisako Sakuma
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; Department of Tropical Medicine, Center for Medical Entomology, The Jikei University School of Medicine, 3-25-8 Nishi-Shimbashi Minato-ku, Tokyo 105-8461, Japan
| | - Yoshie Saito
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Tomoki Umehara
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Keisuke Kamimura
- Department of Brain Development and Neural Regeneration, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo 156-8506, Japan
| | - Nobuaki Maeda
- Department of Brain Development and Neural Regeneration, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo 156-8506, Japan
| | - Timothy J Mosca
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Masayuki Miura
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; AMED-CREST, Japan Agency for Medical Research and Development, 20F Yomiuri Shimbun Building 1-7-1 Otemachi, Chiyoda-ku, Tokyo 100-0004, Japan
| | - Takahiro Chihara
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; AMED-CREST, Japan Agency for Medical Research and Development, 20F Yomiuri Shimbun Building 1-7-1 Otemachi, Chiyoda-ku, Tokyo 100-0004, Japan; Department of Biological Science, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan.
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5
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Bhagat M, Palanichamy JK, Ramalingam P, Mudassir M, Irshad K, Chosdol K, Sarkar C, Seth P, Goswami S, Sinha S, Chattopadhyay P. HIF-2α mediates a marked increase in migration and stemness characteristics in a subset of glioma cells under hypoxia by activating an Oct-4/Sox-2-Mena (INV) axis. Int J Biochem Cell Biol 2016; 74:60-71. [DOI: 10.1016/j.biocel.2016.02.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 01/25/2016] [Accepted: 02/22/2016] [Indexed: 12/14/2022]
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6
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Tang D, Zhang X, Huang S, Yuan H, Li J, Wang Y. Mena-GRASP65 interaction couples actin polymerization to Golgi ribbon linking. Mol Biol Cell 2015; 27:137-52. [PMID: 26538023 PMCID: PMC4694753 DOI: 10.1091/mbc.e15-09-0650] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 10/27/2015] [Indexed: 01/08/2023] Open
Abstract
GRASP65 plays a role in Golgi ribbon formation. Because the gaps between Golgi stacks are heterogeneous and large, it is possible that other proteins may help GRASP65 in ribbon linking. Mena is a novel GRASP65-binding protein that promotes actin elongation and enhances GRASP65 oligomerization to link Golgi stacks into a ribbon. In mammalian cells, the Golgi reassembly stacking protein 65 (GRASP65) has been implicated in both Golgi stacking and ribbon linking by forming trans-oligomers through the N-terminal GRASP domain. Because the GRASP domain is globular and relatively small, but the gaps between stacks are large and heterogeneous, it remains puzzling how GRASP65 physically links Golgi stacks into a ribbon. To explore the possibility that other proteins may help GRASP65 in ribbon linking, we used biochemical methods and identified the actin elongation factor Mena as a novel GRASP65-binding protein. Mena is recruited onto the Golgi membranes through interaction with GRASP65. Depleting Mena or disrupting actin polymerization resulted in Golgi fragmentation. In cells, Mena and actin were required for Golgi ribbon formation after nocodazole washout; in vitro, Mena and microfilaments enhanced GRASP65 oligomerization and Golgi membrane fusion. Thus Mena interacts with GRASP65 to promote local actin polymerization, which facilitates Golgi ribbon linking.
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Affiliation(s)
- Danming Tang
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048
| | - Xiaoyan Zhang
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048
| | - Shijiao Huang
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048
| | - Hebao Yuan
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048
| | - Jie Li
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048
| | - Yanzhuang Wang
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048 Department of Neurology, University of Michigan School of Medicine, Ann Arbor, MI 48109-1048
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7
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Ram R, Wescott AP, Varandas K, Dirksen RT, Blaxall BC. Mena associates with Rac1 and modulates connexin 43 remodeling in cardiomyocytes. Am J Physiol Heart Circ Physiol 2013; 306:H154-9. [PMID: 24186093 DOI: 10.1152/ajpheart.00749.2013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mena, a member of the Ena/VASP family of actin regulatory proteins, modulates microfilaments and interacts with cytoskeletal proteins associated with heart failure. Mena is localized at the intercalated disc (ICD) of adult cardiac myocytes, colocalizing with numerous cytoskeletal proteins. Mena's role in the maintainence of mechanical myocardial stability at the cardiomyocyte ICD remains unknown. We hypothesized that Mena may modulate signals from the sarcolemma to the actin cytoskeleton at the ICD to regulate the expression and localization of connexin 43 (Cx43). The small GTPase Rac1 plays a pivotal role in the regulation of actin cytoskeletal reorganization and mediating morphological and transcriptional changes in cardiomyocytes. We found that Mena is associated with active Rac1 in cardiomyocytes and that RNAi knockdown of Mena increased Rac1 activity significantly. Furthermore, Mena knockdown increased Cx43 expression and altered Cx43 localization and trafficking at the ICD, concomitant with faster intercellular communication, as assessed by dye transfer between cardiomyocyte pairs. In mice overexpressing constitutively active Rac1, left ventricular Mena expression was increased significantly, concomitant with lateral redistribution of Cx43. These results suggest that Mena is a critical regulator of the ICD and is required for normal localization of Cx43 in part via regulation of Rac1.
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Affiliation(s)
- Rashmi Ram
- The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
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8
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Gurzu S, Ciortea D, Ember I, Jung I. The possible role of Mena protein and its splicing-derived variants in embryogenesis, carcinogenesis, and tumor invasion: a systematic review of the literature. BIOMED RESEARCH INTERNATIONAL 2013; 2013:365192. [PMID: 23956979 PMCID: PMC3728509 DOI: 10.1155/2013/365192] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/07/2013] [Revised: 06/16/2013] [Accepted: 07/02/2013] [Indexed: 02/05/2023]
Abstract
The Ena/VASP (enabled/vasodilator stimulated phosphoprotein) family includes the binding actin proteins such as mammalian Ena (Mena), VASP, and Ena-VASP-like. It is known that the perturbation of actin cycle could determine alteration in the mobility of cells and in consequence of organogenesis. Few recent studies have revealed that Mena protein could play a role in breast or pancreatic carcinogenesis. Based on our researches, we observed that the intensity of Mena expression increased from premalignant to malignant lesions in some organs such as large bowel, stomach, cervix, and salivary glands. These findings prove that Mena could be a marker of premalignant epithelial lesions. In premalignant lesions, it could be helpful to define more accurately the risk for malignant transformation. In malignant tumors, correlation of expression of its splice variants could indicate metastatic behavior. In conclusion, we consider that it is necessary to analyze the expression of Mena splice variants in a higher number of cases, in different epithelial lesions, and also in experimental studies to define its exact role in carcinogenesis and also its possible prognostic and predictive values.
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Affiliation(s)
- Simona Gurzu
- Department of Pathology, University of Medicine and Pharmacy of Targu-Mures, 38 Ghe Marinescu Street, 540193 Targu Mures, Romania.
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9
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Jennissen K, Siegel F, Liebig-Gonglach M, Hermann MR, Kipschull S, van Dooren S, Kunz WS, Fässler R, Pfeifer A. A VASP-Rac-soluble guanylyl cyclase pathway controls cGMP production in adipocytes. Sci Signal 2012; 5:ra62. [PMID: 22932701 DOI: 10.1126/scisignal.2002867] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The ubiquitous second messenger cyclic guanosine monophosphate (cGMP) plays an important role in metabolism and promotes brown adipocyte differentiation. We showed that ablation of the gene encoding vasodilator-stimulated phosphoprotein (VASP), a major downstream component of the cGMP signaling cascade, increased cellular cGMP content in brown and white adipocytes and mouse embryonic fibroblasts. VASP-deficient cells showed increased activation of Rac1, which in turn increased the abundance of the cGMP-producing enzyme soluble guanylyl cyclase (sGC), the main receptor for nitric oxide. Consequently, loss of VASP caused increased cGMP concentrations and enhanced brown adipocyte differentiation. Consistent with the in vitro data, we found increased energy expenditure in VASP-deficient mice and exposure to cold triggered enhanced lipolysis and cellular respiration in VASP-deficient brown fat cells. In addition, VASP-deficient mice exhibited increased development of brown-like adipocytes in white fat. Our data revealed that a VASP to Rac to sGC negative feedback loop limited cGMP production, thereby regulating adipogenesis and energy homeostasis.
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Affiliation(s)
- Katja Jennissen
- Institute of Pharmacology and Toxicology, University of Bonn, 53105 Bonn, Germany
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10
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Bravo-Cordero JJ, Hodgson L, Condeelis J. Directed cell invasion and migration during metastasis. Curr Opin Cell Biol 2011; 24:277-83. [PMID: 22209238 DOI: 10.1016/j.ceb.2011.12.004] [Citation(s) in RCA: 341] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 11/26/2011] [Accepted: 12/06/2011] [Indexed: 12/18/2022]
Abstract
Metastasis requires tumor cell dissemination to different organs from the primary tumor. Dissemination is a complex cell motility phenomenon that requires the molecular coordination of the protrusion, chemotaxis, invasion and contractility activities of tumor cells to achieve directed cell migration. Recent studies of the spatial and temporal activities of the small GTPases have begun to elucidate how this coordination is achieved. The direct visualization of the pathways involved in actin polymerization, invasion and directed migration in dissemination competent tumor cells will help identify the molecular basis of dissemination and allow the design and testing of more specific and selective drugs to block metastasis.
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Affiliation(s)
- Jose Javier Bravo-Cordero
- Department of Anatomy and Structural Biology and Gruss Lipper Biophotonics Center, Albert Einstein College of Medicine of Yeshiva University, Bronx, NY 10461, United States.
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11
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Routray C, Liu C, Yaqoob U, Billadeau DD, Bloch KD, Kaibuchi K, Shah VH, Kang N. Protein kinase G signaling disrupts Rac1-dependent focal adhesion assembly in liver specific pericytes. Am J Physiol Cell Physiol 2011; 301:C66-74. [PMID: 21451103 DOI: 10.1152/ajpcell.00038.2011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Nitric oxide (NO) regulates the function of perivascular cells (pericytes), including hepatic stellate cells (HSC), mainly by activating cGMP and cGMP-dependent kinase (PKG) via NO/cGMP paracrine signaling. Although PKG is implicated in integrin-mediated cell adhesion to extracellular matrix, whether or how PKG signaling regulates the assembly of focal adhesion complexes (FA) and migration of HSC is not known. With the help of complementary molecular and cell biological approaches, we demonstrate here that activation of PKG signaling in HSC inhibits vascular tubulogenesis, migration/chemotaxis, and assembly of mature FA plaques, as assessed by vascular tubulogenesis assays and immunofluorescence localization of FA markers such as vinculin and vasodilator-stimulated phosphoprotein (VASP). To determine whether PKG inhibits FA assembly by phosphorylation of VASP at Ser-157, Ser-239, and Thr-278, we mutated these putative phosphorylation sites to alanine (VASP3A, phosphoresistant mutant) or aspartic acid (VASP3D, phosphomimetic), respectively. Data generated from these two mutants suggest that the effect of PKG on FA is independent of these three phosphorylation sites. In contrast, activation of PKG inhibits the activity of small GTPase Rac1 and its association with the effector protein IQGAP1. Moreover, PKG activation inhibits the formation of a trimeric protein complex containing Rac1, IQGAP1, and VASP. Finally, we found that expression of a constitutively active Rac1 mutant abolishes the inhibitory effects of PKG on FA formation. In summary, our data suggest that activation of PKG signaling in pericytes inhibits FA formation by inhibiting Rac1.
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Affiliation(s)
- Chittaranjan Routray
- GI Research Unit and Cancer Cell Biology Program, Mayo Clinic, Rochester, Minnesota 55905, USA
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12
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Higashi M, Yu J, Tsuchiya H, Saito T, Oyama T, Kawana H, Kitagawa M, Tamaru JI, Harigaya K. Visualization of the Activity of Rac1 Small GTPase in a Cell. Acta Histochem Cytochem 2010; 43:163-8. [PMID: 21245983 PMCID: PMC3015054 DOI: 10.1267/ahc.10025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Accepted: 11/17/2010] [Indexed: 11/22/2022] Open
Abstract
Rho family G proteins including Rac regulate a variety of cellular functions, such as morphology, motility, and gene expression. Here we developed a fluorescence resonance energy transfer-based analysis in which we could monitor the activity of Rac1. To detect fluorescence resonance energy transfer, yellow fluorescent protein fused Rac1 and cyan fluorescent protein fused Cdc42-Rac1-interaction-binding domain of Pak1 protein were used as intermolecular probes of FRET. The fluorophores were separated with linear unmixing method. The fluorescence resonance energy transfer efficiency was measured by acceptor photobleaching assisted assay. With these methods, the Rac1 activity was visualized in a cell. The present findings indicate that this approach is sensitive enough to achieve results similar to those from ratiometric fluorescence resonance energy transfer analysis.
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Affiliation(s)
- Morihiro Higashi
- Department of Pathology, Saitama Medical Center, Saitama Medical University
- Molecular and Tumor Pathology, Chiba University Graduate School of Medicine
| | - Jianyong Yu
- Molecular and Tumor Pathology, Chiba University Graduate School of Medicine
| | - Hiroshi Tsuchiya
- Molecular and Tumor Pathology, Chiba University Graduate School of Medicine
| | - Teruyoshi Saito
- Molecular and Tumor Pathology, Chiba University Graduate School of Medicine
| | - Toshinao Oyama
- Molecular and Tumor Pathology, Chiba University Graduate School of Medicine
| | | | - Motoo Kitagawa
- Molecular and Tumor Pathology, Chiba University Graduate School of Medicine
| | - Jun-ichi Tamaru
- Department of Pathology, Saitama Medical Center, Saitama Medical University
| | - Kenichi Harigaya
- Molecular and Tumor Pathology, Chiba University Graduate School of Medicine
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Kang N, Yaqoob U, Geng Z, Bloch K, Liu C, Gomez T, Billadeau D, Shah V. Focal adhesion assembly in myofibroblasts fosters a microenvironment that promotes tumor growth. THE AMERICAN JOURNAL OF PATHOLOGY 2010; 177:1888-900. [PMID: 20802179 DOI: 10.2353/ajpath.2010.100187] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Cells within the tumor microenvironment influence tumor growth through multiple mechanisms. Pericytes such as hepatic stellate cells are an important cell within the tumor microenvironment; their transformation into highly motile myofibroblasts leads to angiogenesis, stromal cell recruitment, matrix deposition, and ensuing tumor growth. Thus, a better understanding of mechanisms that regulate motility of pericytes is required. Focal adhesions (FAs) form a physical link between the extracellular environment and the actin cytoskeleton, a requisite step for cell motility. FAs contain a collection of proteins including the Ena/VASP family member, vasodilator-stimulated phosphoprotein (VASP); however, a role for VASP in FA development has been elusive. Using a comprehensive siRNA knockdown approach and a variety of VASP mutants coupled with complementary cell imaging methodologies, we demonstrate a requirement of VASP for optimal development of FAs and cell spreading in LX2 liver myofibroblasts, which express high levels of endogenous VASP. Rac1, a binding partner of VASP, acts in tandem with VASP to regulate FAs. In vivo, perturbation of Ena/VASP function in tumor myofibroblast precursor cells significantly reduces pericyte recruitment to tumor vasculature, myofibroblastic transformation, tumor angiogenesis, and tumor growth, providing in vivo pathobiologic relevance to these findings. Taken together, our results identify Ena/VASP as a significant modifier of tumor growth through regulation of FA dynamics and ensuing pericyte/myofibroblast function within the tumor microenvironment.
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Abstract
Although now dogma, the idea that nonvertebrate organisms such as yeast, worms, and flies could inform, and in some cases even revolutionize, our understanding of oncogenesis in humans was not immediately obvious. Aided by the conservative nature of evolution and the persistence of a cohort of devoted researchers, the role of model organisms as a key tool in solving the cancer problem has, however, become widely accepted. In this review, we focus on the nematode Caenorhabditis elegans and its diverse and sometimes surprising contributions to our understanding of the tumorigenic process. Specifically, we discuss findings in the worm that address a well-defined set of processes known to be deregulated in cancer cells including cell cycle progression, growth factor signaling, terminal differentiation, apoptosis, the maintenance of genome stability, and developmental mechanisms relevant to invasion and metastasis.
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Affiliation(s)
- Natalia V. Kirienko
- University of Wyoming, College of Agriculture, Department of Molecular Biology, Dept 3944, 1000 E. University Avenue, Laramie, WY 82071
| | - Kumaran Mani
- University of Wyoming, College of Agriculture, Department of Molecular Biology, Dept 3944, 1000 E. University Avenue, Laramie, WY 82071
| | - David S. Fay
- University of Wyoming, College of Agriculture, Department of Molecular Biology, Dept 3944, 1000 E. University Avenue, Laramie, WY 82071
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15
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Franco DL, Rezával C, Cáceres A, Schinder AF, Ceriani MF. ENA/VASP downregulation triggers cell death by impairing axonal maintenance in hippocampal neurons. Mol Cell Neurosci 2010; 44:154-64. [PMID: 20230896 DOI: 10.1016/j.mcn.2010.03.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Revised: 01/28/2010] [Accepted: 03/05/2010] [Indexed: 11/28/2022] Open
Abstract
Neurodegenerative diseases encompass a broad variety of motor and cognitive disorders that are accompanied by death of specific neuronal populations or brain regions. Cellular and molecular mechanisms underlying these complex disorders remain largely unknown. In a previous work we searched for novel Drosophila genes relevant for neurodegeneration and singled out enabled (ena), which encodes a protein involved in cytoskeleton remodeling. To extend our understanding on the mechanisms of ENA-triggered degeneration we now investigated the effect of silencing ena ortholog genes in mouse hippocampal neurons. We found that ENA/VASP downregulation led to neurite retraction and concomitant neuronal cell death through an apoptotic pathway. Remarkably, this retraction initially affected the axonal structure, showing no effect on dendrites. Reduction in ENA/VASP levels blocked the neuritogenic effect of a specific RhoA kinase (ROCK) inhibitor, thus suggesting that these proteins could participate in the Rho-signaling pathway. Altogether these observations demonstrate that ENA/VASP proteins are implicated in the establishment and maintenance of the axonal structure and that a change on their expression levels triggers neuronal degeneration.
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Affiliation(s)
- D Lorena Franco
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas-Buenos Aires (IIB-BA, CONICET), Argentina
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