Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UMLS:C0001511 (Adhesion)
5,955 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The expression of the VLA-integrins alpha 2, alpha 3, alpha 5 and alpha 6 was studied immunohistochemically in tissue samples from ductal pancreatic cancer, chronic pancreatitis, normal pancreas and in 8 cell lines of ductal human pancreatic cancer. Furthermore, adhesion assays on purified extracellular matrix (ECM)-compounds were used to define the function of alpha 2, alpha 3, alpha 5 and alpha 6 in pancreatic cancer cells. Immunohistochemically, VLA alpha 2 and VLA alpha 6 were moderately to strongly expressed on the basal surface of ductal and acinar cells in normal pancreatic tissue, while centro-acinar cells predominantly expressed VLA alpha 3 and VLA alpha 5. Pancreatic carcinoma showed intense staining for VLA alpha 2 and VLA alpha 6 with a diffuse distribution on the cell surface. The redistribution of VLA alpha 2 and VLA alpha 6 may reflect a loss of spatial arrangement of tumor cells and their ability to interact randomly with extracellular matrix structures during invasion and metastasis. Expression of VLA alpha 3 and VLA alpha 5 in pancreatic carcinoma was heterogeneous, ranging from moderate to weak, and was lost in about 50% of the cells. Two pancreatic carcinoma cell lines (PC 3, PC 44) were further investigated in adhesion assays. Monoclonal antibodies (MAbs) against alpha 2 (GI 9, 10-G-11) were able to inhibit tumor-cell adhesion to collagen IV (59%-72%) in both cell lines. A MAb against alpha 6 (GoH3) inhibited tumor-cell adhesion to laminin (52%-86%) in both cell lines. These results suggest that alpha 2 is a collagen-binding site and alpha 6 a laminin-binding site in pancreatic cancer cells. The anti-alpha 5-MAb SAM I inhibited adhesion of PC3 to fibronectin (76%), being without effect in PC44. Adhesion of both cell lines to fibronectin was almost completely inhibited by RGDS (85%-88%). Thus, alpha 5 is a functionally important fibronectin binding site in some pancreatic carcinoma cells, suggesting further RGD-dependent fibronectin binding sites in other pancreatic carcinoma cells.
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PMID:Expression and function of VLA-alpha 2, -alpha 3, -alpha 5 and -alpha 6-integrin receptors in pancreatic carcinoma. 133 Sep 37

Adhesion of T cells to extracellular matrix (ECM) proteins through VLA integrin receptors is crucial for lymphocyte trafficking, tissue localization and inflammatory function. We have investigated the expression of different VLA integrins (VLA-1-5) on peripheral blood (PB) and synovial fluid (SF) T lymphocytes from patients with rheumatoid arthritis (RA). Their expression on different cell types from synovial membrane (SM) is also reported. The role of VLA-4 fibronectin (FN) receptors in the interaction of activated SF T cells from RA patients with a 38-kD fragment of FN has been previously demonstrated. Here we have focused functional studies on VLA-5 as an alternative FN receptor for RA T cells. A significant higher proportion of SF T cells were able to bind to an 80-kD fragment of FN, containing the Arg-Gly-Asp (RGD) cell binding site, compared with PB T cells. This attachment was almost completely inhibited by anti-VLA-5 MoAbs as well as by RGD peptides. This enhanced capability by SF T cells appears to be independent of the level of the surface expression of the receptor and correlates better with their activation state as determined by the expression of the activation molecule AIM (CD69). The evidence for the expression of VLA heterodimers on both SF and SM cells from RA patients suggests the possible implication of ECM proteins in mediating and perpetuating inflammation in vivo.
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PMID:VLA family in rheumatoid arthritis: evidence for in vivo regulated adhesion of synovial fluid T cells to fibronectin through VLA-5 integrin. 137 52

The human promyelocytic cell line NB4 exhibited a weak adhesion capacity for bone marrow-derived stromal cells and their extracellular matrices (5-15% of adherent cells). Adhesion was enhanced by pulse-treatment of cells with phorbolester (PMA 10(-7) M). Adhesion was induced within minutes, was fibronectin-specific, and affected up to 100% of the treated cells. This biological response to PMA resulted from the activation of protein kinase C (PKC), since PKC inhibitors (staurosporine, sphingosine, CGP 41251, and calphostin C) prevented the phenomenon. Phenotypical analysis of integrin receptor expression (particularly FN receptors VLA-4 and VLA-5) at the membrane of untreated or PMA-treated cells revealed that PMA induced no significant modification of the level of expression of these receptors. However, inhibition studies carried out with anti-VLA monoclonal antibodies demonstrated that the FN-specific adhesion triggered by PKC involved the alpha 5 beta 1 FN-specific receptors (VLA-5). We showed that the binding of NB4 cells to fibronectin was RGD-dependent. PMA-induced adhesion was not correlated to phosphorylation of the VLA-5 receptor. These findings may partially explain the malignant behaviour of these cells: The loss of their capacity to adhere to stromal cells may arrest differentiation and explain the large number of leukemic cells in the circulation.
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PMID:Phorbol ester-induced promyelocytic leukemia cell adhesion to marrow stromal cells involves fibronectin specific alpha 5 beta 1 integrin receptors. 138 76

The integrin heterodimer VLA-2, previously known as a collagen receptor, is now shown also to be a laminin receptor. Adhesion of the human melanoma cell line LOX to laminin was inhibited by anti-VLA alpha 2 antibodies. Because VLA-2-mediated LOX cell attachment to laminin was not inhibited by digestion with collagenase, collagen contamination of laminin was not a factor. In addition, VLA-2 from LOX cells bound to immobilized laminin, and binding was disrupted by EDTA but not by Arg-Gly-Asp (RGD) peptides. VLA-3 also bound to laminin-Sepharose, although less avidly than VLA-2. Thus, at least four separate members of the integrin beta 1 subfamily serve as laminin receptors--i.e., VLA-2 and VLA-3 (this study) together with VLA-1 and VLA-6 (other reports). Whereas LOX and other cell lines used VLA-2 as both a laminin and collagen receptor, fibroblast VLA-2 mediated collagen but not laminin binding. Likewise, VLA-2 from platelets did not interact with laminin. Despite this functional discordancy, VLA-2 from laminin-binding and nonbinding sources was indistinguishable by all immunochemical and biochemical criteria examined. Thus, functional differences in VLA-2 may be due to cell type-specific modulation.
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PMID:The human integrin VLA-2 is a collagen receptor on some cells and a collagen/laminin receptor on others. 255 34

Adhesion of tumour cells to cultured bone marrow stromal cells has been studied in an in vitro model system. Stromal cells were isolated from bone marrow aspirates. Immunohistochemical and electron microscopical analysis revealed a uniform cell monolayer of myofibroblastic cells, expressing fibroblast antigens and smooth muscle actin. Cell interactions with tumour cells lines showed different patterns. The K562 cells bound in low numbers to stromal cells. HEL-DR- and HL60 cells adhered to stromal cells showing an enlarged cell contact area (spreading) attenuated by distinct contact sites and they invaded the monolayer. Adhesion molecules, important for cell contacts, were detected on tumor cells. Different VLA antigens were detected on tumour cells, but on stromal cells only VLA-5 and CD29 were found. In vitro inhibition studies with mAbs against adhesion molecules indicated two major pathways for binding of tumour cells to stromal cells: VCAM-1/VLA-4 and fibronectin/VLA-5. Variation in inhibition of mAbs to VLA-4 and VCAM-1 indicated the existence of critical epitopes in the adhesion of tumour cells.
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PMID:Interaction of tumour cells with cultured stromal cells from human bone marrow. 753 64

Interactions between tumour cells and the endothelium are vital to the formation of haematogenous metastases. Binding to model endothelium of one oestrogen receptor positive breast carcinoma cell line (MCF-7) and one receptor negative line (HS578T) was examined in vitro together with endothelial retraction induced by these tumour cells. Adhesion was inhibited by monoclonal antibodies specific for the VLA integrins and by peptides containing the RGD motif which is commonly recognised as a ligand by the VLA adhesion molecules. However, binding of the two tumour cell lines was inhibited by monoclonal antibodies specific for different VLA molecules; anti-alpha 6 beta 1 inhibited MCF-7 adhesion but anti-alpha 5 beta 1 inhibited Hs578T. These results were consistent with flow cytometric quantification of the expression of these VLA integrins on the surfaces of the two tumour cell lines. Enzyme-linked immunosorbent assays (ELISA) demonstrated that laminin was present on the endothelial cell surface but collagen IV was absent. ELISA failed to detect increased exposure of the subendothelial matrix during the first hour after addition of either cancer cell type. This was supported by assays which demonstrated maintenance of the endothelial permeability barrier during this period. Slight endothelial retraction was detected within 2 hours of the addition of tumour cells. It is concluded that binding between tumour cells and confluent endothelium is inhibited by the blockade of adhesion molecules which are normally associated with interactions between the cell and the subendothelial matrix. Tumour cell to matrix interactions rather than direct tumour to endothelial cell adhesion may be the limiting step in tumour cell binding to the endothelium.
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PMID:The role of beta 1 integrins in adhesion of two breast carcinoma cell lines to a model endothelium. 753 54

In the present study we compare human dermal fibroblasts from donors of different age and from sites differing in sun exposure for their capacity to adhere to collagen or fibronectin. Attachment of cells was not dependent on the collagen concentration but was clearly dependent on the fibronectin concentration used for the coating of the plastic surfaces. Attachment of fibroblasts to collagen and fibronectin is dominated by specific integrin binding: only few cells were able to attach to collagen after inhibition with an anti-VLA 2 antibody, or to attach to fibronectin after inhibition with an anti-VLA 5 antibody. On unexposed sites, cells from old donors showed a significantly increased adhesion capacity on collagen (plus 50.7%) and on fibronectin (plus 62.4%) and an increased staining pattern of VLA 2 and VLA 5 integrins in immunohistochemistry in comparison with young donors. In contrast fibroblasts of chronically sun-exposed skin had a significantly decreased adhesion capacity both on collagen (minus 55.3%) and on fibronectin (minus 46.5%) and a poor staining pattern of the above integrins in comparison with cells from solely aged skin (unexposed sites of old donors). Adhesion of all cells could be inhibited by specific integrin antibodies showing that the employed antibodies were able to detect the epitopes responsible for attachment. Intrinsic and extrinsic aging are able to alter cellular properties of mesenchymal cells, such as adhesion to physiologically relevant macromolecules of the extracellular matrix.
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PMID:Attachment of intrinsically and extrinsically aged fibroblasts on collagen and fibronectin. 769 22

We investigated the molecular mechanism(s) by which platelets adhere to an artificial surface exposed to plasma, using polystyrene microtiter plates pretreated with plasma. Washed platelets labelled with 51Cr were incubated with the plates under static conditions. Prostaglandin E1(PGE1) was added to the platelets to prevent platelet-platelet interactions. Adhesion required the presence of a divalent cation such as Mg++ or Ca++. Polyclonal anti-fibrinogen antibody inhibited adhesion by 70%. Polyclonal antibodies against fibronectin, vitronectin, von Willebrand's Factor, and the Fc portion of human IgG, had no effect on adhesion. Platelets adhered normally to a surface pretreated with plasma from a patient with severe von Willebrand's disease. No platelet adhesion occurred when the surface was pretreated with an afibrinogenemic plasma. Monoclonal antibodies against platelet membrane GPIIb-IIIa, potent inhibitors of ADP-induced fibrinogen binding to platelets, completely inhibited adhesion. Monoclonal antibodies against the GPIb alpha subunit and GPIc(VLA alpha 5) showed no inhibitory effects on adhesion. Platelets from a patient with Glanzmann's thrombasthenia (type I) did not adhere to the surface pretreated with normal plasma. These results suggest that plasma fibrinogen adsorbed onto the surface and that platelet membrane glycoprotein(GP)IIb-IIIa were responsible for adhesion in an activation-independent manner.
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PMID:Evidence that plasma fibrinogen and platelet membrane GPIIb-IIIa are involved in the adhesion of platelets to an artificial surface exposed to plasma. 813 6

The mechanisms responsible for the accumulation of eosinophils at sites of allergic and other inflammatory reactions are unknown, but recent studies have implicated both eosinophil and endothelial adhesion molecules in this process. However, less well studied have been the adhesive interactions between eosinophils and the subendothelial basement membrane and interstitial connective tissues. To test the hypothesis that eosinophils might interact with extracellular matrix proteins, we analyzed purified human eosinophils for the expression and function of various beta 1 integrins. Using indirect immunofluorescence and flow cytometry, purified eosinophils from mildly allergic donors were found to consistently express the integrin subunits beta 1 (CD29), alpha 4 (CD49d, very late activation antigen [VLA]-4 alpha), and alpha 6 (CD49f, VLA-6 alpha). No significant expression of the alpha 1, alpha 2, alpha 3, alpha 5, or beta 4 subunits was detected. Platelet contamination of the eosinophil preparations was excluded by light microscopy and by the inability to detect expression of platelet glycoproteins alpha v, CD41b, and CD42b. Immunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of eosinophils confirmed the expression of cell-surface beta 1, alpha 4, and alpha 6. Furthermore, eosinophils purified from allergic donors were shown to adhere to plate-bound laminin, but not to type 1 or type 4 collagen. Adhesion to laminin was concentration-dependent, required divalent cations, and was completely and specifically inhibited by the anti-alpha 6 monoclonal antibody (MoAb) GoH3 and by the anti-beta 1 MoAb 33B6. Interestingly, the anti-beta 1 MoAb 18D3 (which like 33B6 blocks eosinophil binding to VCAM-1) did not inhibit eosinophil adhesion to laminin, suggesting that there are functionally distinct epitopes on the beta 1 subunit. Eosinophils purified from 4 healthy, nonallergic donors also showed alpha 6-dependent adhesion to laminin, although these cells adhered less well. These studies establish the expression of alpha 6 beta 1 on human eosinophils and document its function as a laminin receptor. Interaction of eosinophil alpha 6 beta 1 with laminin, eg, in basement membranes, may contribute to the localization of these cells at inflammatory sites in vivo.
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PMID:Expression of a functional laminin receptor (alpha 6 beta 1, very late activation antigen-6) on human eosinophils. 821 35

Adhesion molecules (AM) are cell surface proteins which interact with ligands and mediate cell-cell bindings. Possibly, the AM are involved in the spermatozoal adhesion to oocytes. Human spermatozoa showed several adhesion molecules on their surface: the alpha chains of the beta 1-integrins VLA alpha 4 (CDw 49d), VLA alpha 5 (CDw 49e) and VLA alpha 6 (CDw 49f), the beta-chain of beta 2-integrins (CD 18) and the matrix proteins laminin and fibronectin. Semen samples with severe teratozoospermia were characterized by a significantly lower percentage (P < 0.01) of spermatozoa with VLA alpha 4, VLA alpha 5 and laminin. VLA alpha 5 (the alpha-chain of the fibronectin receptor) showed the most significant difference between the "normal" and teratozoospermic semen sample groups. This phenomenon could contribute to the explanation of a lower fertilizing capacity of teratozoospermic semen samples.
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PMID:Semen samples with teratozoospermia show a lower percentage of spermatozoa with detectable adhesion molecules (AM). 827 Mar 77


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