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V Integrin (v + integrin)

Distribution by Scientific Domains

Medical Sciences	62%

Selected Abstracts

Expression, regulation, and function of ,V integrins in hepatocellular carcinoma: An in vivo and in vitro study

HEPATOLOGY, Issue 2 2002
Mimoun Nejjari
The expression of ,V integrins by neoplastic cells contributes to the promotion of local invasion and metastasis. The most characteristic extracellular ligands of ,V integrins are vitronectin and fibronectin. Hepatocytes are the main source of vitronectin, and the capacity to synthesize and secrete vitronectin is usually retained in hepatocellular carcinoma. The aim of this study was to explore the expression, regulation, and functional role of ,V integrins in hepatocellular carcinoma. We first analyzed the expression of ,V integrins and their ligands fibronectin and vitronectin in 80 cases of hepatocellular carcinoma. ,V integrin chain was detected in 44 cases and vitronectin in 50. Twenty-four of the 44 ,V-positive tumors contained large amounts of vitronectin. These cases presented more frequently with adverse histoprognostic factors, including infiltrative growth pattern (62.5%), lack of capsule (71%), presence of capsular invasion (57%), and satellite nodules (50%). We then used HepG2 and Hep3B cell lines as in vitro models to study ,V integrin regulation and function. HepG2 and Hep3B cells expressed ,V integrin chain and used ,V,1 and ,V,5 for adhesion and migration on vitronectin. Tumor necrosis factor (TNF) , and transforming growth factor (TGF) , significantly increased the expression levels of ,V integrins and stimulated the adhesion and migration of both HepG2 and Hep3B cell lines on vitronectin. The effects of growth factors on cell adhesion and migration were reproduced by incubation with conditioned medium from rat liver myofibroblasts. In conclusion, our results support the existence of an ,V integrin/vitronectin connection in hepatocellular carcinoma and suggest that this connection may be an adverse prognostic factor. [source]

Osteopontin as a new player in mast cell biology

EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 2 2008
Silvia Bulfone-Paus
Abstract The secreted glycoprotein osteopontin (OPN) sets into motion an astounding variety of activities that range from bone remodeling via immunomodulation to the inhibition of apoptosis. In the current issue of the European Journal of Immunology, OPN now also enters mast cell biology and the regulation of IgE-dependent immune responses since it is reported that connective tissue-type mast cells from fetal murine skin constitutively secrete biologically active OPN. Moreover, it is shown that, in vitro, OPN augments IgE-mediated mast cell degranulation and migration via ligand binding to cognate OPN receptors on the mast cell surface (CD44, ,v integrin) and that the magnitude of an IgE-mediated passive cutaneous anaphylaxis reaction is augmented by OPN in vivo. Here, we discuss why this newly discovered property of OPN fits well into the emerging concept that OPN may serve as a multi-purpose environmental damage-response protein. See accompanying article: http://dx.doi.org/10.1002/eji200737057 [source]

,v vitronectin receptors in vascular-mediated disorders

MEDICINAL RESEARCH REVIEWS, Issue 2 2003
Shaker A. Mousa
Abstract Various integrin antagonist candidates including antibodies, cyclic peptides, peptidomimetics, and non-peptides have been clinically evaluated and shown to successfully modulate certain disease processes. This review will focus on the key role of the ,v integrin (,v,3 and ,v,5) in vascular disorders such as restenosis and angiogenesis-mediated disorders. © 2002 Wiley Periodicals, Inc. Med Res Rev, 23, No. 2, 190,199, 2003 [source]

Rapamycin inhibits lung metastasis of B16 melanoma cells through down-regulating alphav integrin expression and up-regulating apoptosis signaling

CANCER SCIENCE, Issue 2 2010
Zhuoshun Yang
Currently available data indicate the potential application of rapamycin and its analogues in the clinic as anticancer therapeutic agents through inhibiting tumor cell growth and tumor angiogenesis. However, whether rapamycin can directly suppress tumor metastasis remains unclear. In the present study, we demonstrated that rapamycin treatment results in reduced formation of metastatic nodules in the lung by B16 cells. This is due to two mechanisms. First, the expression of ,v integrin is down-regulated by rapamycin treatment, and subsequently, the phosphorylation of focal adhesion kinase (FAK) is reduced. Second, rapamycin promotes apoptosis by up-regulating the proapoptotic molecules Bid and Bax and down-regulating Bcl-xL. Blocking the apoptosis pathway by pan-caspase inhibitor zVAD partially reversed the suppression of rapamycin in B16 metastasis. Interestingly, rapamycin up-regulates Bax and Bid in B16 cells via the S6K1 pathway and down-regulates the expression of ,v integrin via other pathway(s). In addition, our data showed that autophagy was not involved in the mechanisms of rapamycin-mediated metastasis suppression. Our findings demonstrate a potential anti-metastatic effect of rapamycin via down-regulating ,v integrin expression and up-regulating apoptosis signaling, suggesting that rapamycin might be worthy of clinical evaluation as an antimetastatic agent. (Cancer Sci 2009) [source]

Microglial expression of ,v,3 and ,v,5 integrins is regulated by cytokines and the extracellular matrix: ,5 Integrin null microglia show no defects in adhesion or MMP-9 expression on vitronectin

GLIA, Issue 7 2009
Richard Milner
Abstract As the primary immune effector cells in the CNS, microglia play a central role in regulating inflammation. The extracellular matrix (ECM) protein vitronectin is a strong inducer of microglial activation, switching microglia from a resting into an activated potentially destructive phenotype. As the activating effect of vitronectin is mediated by ,v integrins, the aim of the current study was to evaluate the requirement of the ,v,5 integrin in mediating microglial adhesion and activation to vitronectin, by studying these events in ,5 integrin-null murine microglia. Surprisingly, ,5 integrin null microglia were not defective in adhesion to vitronectin. Further analysis showed that microglia express the ,v,3 integrin, in addition to ,v,5. Flow cytometry revealed that microglial ,v integrin expression is regulated by cytokines and ECM proteins. ,v,3 integrin expression was downregulated by IFN-,, TNF, LPS, and TGF-,1. ,v,5 expression was also reduced by IFN-,, TNF, and LPS, but strongly increased by the antiactivating factors TGF-,1 and laminin. Gel zymography revealed that ,5 integrin null microglia showed no deficiency in their expression of matrix metalloproteinase (MMP)-9 in response to vitronectin. Taken together, these data show that microglia express two different ,v integrins, ,v,3 and ,v,5, and that expression of these integrins is independently regulated by cytokines and ECM proteins. Furthermore, it reveals that the ,v,5 integrin is not essential for mediating microglial adhesion and MMP-9 expression in response to vitronectin. © 2008 Wiley-Liss, Inc. [source]

Influence of Cold Plasma Atmospheric Jet on Surface Integrin Expression of Living Cells

PLASMA PROCESSES AND POLYMERS, Issue 3-4 2010
Alexey Shashurin
Abstract The effects induced in cells due to treatment with cold atmospheric plasma jet are studied. Cell migration rate is measured by means of time-lapse microscopy. In order to characterize cell surface integrin expression, the fluorescent response of cells after surface integrins are stained with specific antibodies is measured by flow cytometry. We show that treatment of cells with plasma jet affects the cells on sub-cellular level, namely decreases expression of cell surface integrins (,1 and ,v integrins were tested). This change in integrin expression might be the original cause for the effects observed on cellular level, such as reduced cell migration rate and cell detachment observed experimentally. [source]

Inhibition of angiogenesis by interleukin-4 gene therapy in rat adjuvant-induced arthritis

ARTHRITIS & RHEUMATISM, Issue 8 2006
Christian S. Haas
Objective Interleukin-4 (IL-4) can modulate neovascularization. In this study, we used a gene therapy approach to investigate the role of IL-4 in angiogenesis in rat adjuvant-induced arthritis (AIA), a model for rheumatoid arthritis. Methods Rats received an adenovirus producing IL-4 (AxCAIL-4), a control virus without insert, or control vehicle (phosphate buffered saline) intraarticularly before arthritis onset. At peak onset of arthritis, rats were killed. Vascularization was determined in the synovial tissue, and correlations with inflammation were assessed. Ankle homogenates were used in angiogenesis assays in vitro and in vivo, and protein levels of cytokines and growth factors were assessed by enzyme-linked immunosorbent assay. Synovial tissue expression of ,v integrins was determined by immunohistochemistry. Results IL-4 induced a reduction in synovial tissue vessel density, which was paralleled by a decrease in inflammation. AxCAIL-4 joint homogenates significantly (P < 0.05) inhibited both endothelial cell (EC) migration and tube formation in vitro. Similarly, AxCAIL-4 inhibited capillary sprouting in the rat aortic ring assay, and vessel growth in the in vivo Matrigel plug assay. The angiostatic effect occurred despite high levels of vascular endothelial growth factor (VEGF), and was associated with down-regulation of the proangiogenic cytokines IL-18, CXCL16, and CXCL5 and up-regulation of the angiogenesis inhibitor endostatin. Of interest, AxCAIL-4 also resulted in decreased EC expression of the ,v and ,3 integrin chains. Conclusion In rat AIA, IL-4 reduces synovial tissue vascularization via angiostatic effects, mediates inhibition of angiogenesis via an association with altered pro- and antiangiogenic cytokines, and may inhibit VEGF-mediated angiogenesis and exert its angiostatic role in part via ,v,3 integrin. This knowledge of the specific angiostatic effects of IL-4 may help optimize target-oriented treatment of inflammatory arthritis. [source]