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

Adhesion molecules are involved in intracellular signaling in various physiological and pathological processes including metastasis and growth of tumor cells. Tumor cells interact with various host cells as well as with extracellular matrices through certain adhesion molecules such as integrins. We here propose that stimulation of beta1 integrin reduces intercellular adhesion molecule (ICAM)-1-mediated interaction of lung cancer cells with CTLs. This concept is based on the following findings: (a) engagement of beta1 integrins on certain lung cancer cells by a specific antibody or by ligand matrices such as fibronectin and collagen markedly reduced ICAM-1 expression on the cell surface and induced sICAM-1; (b) down-regulation of ICAM-1 by stimulation of beta1 integrins was abrogated by tyrosine kinase inhibitors or by transfection of dominant negative truncations of focal adhesion kinase (FAK); (c) engagement of beta1 integrins also reduced ICAM-1-dependent adhesion of lung cancer cells to T cells, a process completely inhibited by tyrosine kinase inhibitors and by transfection of dominant negative forms of FAK; and (d) stimulation of beta1 integrins prevented killing of lung cancer cells by autologous CTLs. In malignant tumors, cancer cells, including lung cancer cells, are surrounded by extracellular matrix proteins such as fibronectin and collagen. This suggests that the engagement of beta1 integrins by matrix proteins potentially occurs in cancer cells in vivo and that continuous stimulation via beta1 integrins reduces ICAM-1-expression, ICAM-1-mediated adhesion of cancer cells to CTLs and their killing by CTLs. Our results suggest that such processes can lead to the escape of lung cancer cells in vivo from immunological surveillance.
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PMID:Stimulation of beta1 integrin down-regulates ICAM-1 expression and ICAM-1-dependent adhesion of lung cancer cells through focal adhesion kinase. 1128 Jul 62

Adhesion of polymorphonuclear leukocytes (PMNLs) to activated platelets requires a P-selectin-triggered, tyrosine kinase-dependent adhesiveness of Mac-1 and is accompanied by tyrosine phosphorylation of a 110-kd protein (P-110) in PMNLs. Inhibitors of SRC tyrosine kinases were found to inhibit PMNL adhesion to activated platelets or to P-selectin expressing Chinese hamster ovary (CHO-P) cells and the tyrosine phosphorylation of P-110. Adhesion of PMNLs to activated platelets or to CHO-P cells stimulated activity of LYN and HCK. Monoclonal antibody blockade of P-selectin or beta2-integrins reduced the activation of both kinases. In PMNLs either adherent to platelets or aggregated by P-selectin-IgG chimera, Mac-1 was rapidly redistributed to the Triton X-100-insoluble cytoskeletal fraction, and large clusters of Mac-1 colocalized with patches of F-actin at the sites of cell-cell contact. In PMNLs stimulated by P-selectin-IgG chimera, SRC kinase inhibition impaired Mac-1 clustering, F-actin accumulation, and CD18 redistribution to the cytoskeleton. Disruption of the actin filament network by cytochalasin D prevented PMNL-platelet adhesion and P-selectin-induced PMNL aggregation and impaired the clustering of Mac-1. In agreement with the requirement for the beta2-integrin in the functional up-regulation of LYN and HCK, integrin blockade by monoclonal antibodies resulted in a complete inhibition of P-selectin-induced Mac-1 clustering and F-actin accumulation. Taken together, the results indicate that, after an initial P-selectin-triggered beta2-integrin interaction with the ligand, SRC kinases are activated and allow the remodeling of cytoskeleton-integrin linkages and integrin clustering that finally strengthen cell-cell adhesion. This model highlights a new role for SRC kinases in a regulatory loop by which the Mac-1 promotes its own adhesive function.
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PMID:Platelet/polymorphonuclear leukocyte adhesion: a new role for SRC kinases in Mac-1 adhesive function triggered by P-selectin. 1141 69

Adhesion molecules and C-C chemokines play an important role in the accumulation of eosinophils in allergic inflammation. In the present study, the expression and function of adhesion molecules on eosinophils from asthmatic patients and involvement of RANTES and eotaxin were examined. Eosinophils isolated by the CD16 negative selection method were stimulated with or without RANTES or eotaxin. Expression of b integrins on eosinophils and the functional adherence to recombinant soluble intercellular adhesion molecule-1 (r-sICAM-1)-coated plates were examined. Compared with normal subjects, eosinophils from asthmatic patients showed increased expression of b2 integrins and functional adherence to r-sICAM-1-coated plates. RANTES and eotaxin augmented the functional adherence of eosinophils without a significant upregulation of b2 integrins. Anti-b2 integrin antibody inhibited the augmentative effect on eosinophil adherence of RANTES and eotaxin. Pertussis toxin, wortmannin, and genistein inhibited chemokine-induced adherence. RANTES and eotaxin are closely related to eosinophil accumulation not only as chemotactic agents but also as augmentative agents for eosinophil adherence through involvement in functional eosinophil adherence to ICAM-1 by a possible qualitative change of b2 integrins. Pertussis toxin-sensitive G proteins, PI3 kinase, and tyrosine kinase are involved in signal transduction leading to activation of b2 integrins on eosinophil following stimulation with RANTES and eotaxin.
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PMID:Possible involvement of C-C chemokines in functional augmentation of adhesion molecules in asthmatic patients. 1248 19

Adhesion between neighbouring epithelial cells is a crucial and tightly controlled process. In the gastrointestinal tract, the integrity of cell-cell contacts is essential for the regulation of electrolyte absorption and for the prevention of tumour metastasis. We recently showed that migration of the gastric epithelial cell line IMGE-5 is stimulated by the nonamidated form of the hormone gastrin(17). Here, we examine the effect on cell-cell adhesion of the prohormone progastrin, the concentration of which is increased in the plasma of patients with colorectal carcinoma. Progastrin induced the dissociation of both tight junction (TJ) and adherens junction (AJ) complexes in IMGE-5 cells. In progastrin-secreting DLD-1 human colorectal carcinoma cells, expression of an antisense gastrin construct restored membrane localisation of zonula occludens-1 (ZO-1), occludin, beta-catenin and E-cadherin. This restoration was reversed by treatment with exogenous progastrin. Endogenous or exogenous progastrin also increased the paracellular flux of mannitol, and induced cell migration of several gastrointestinal cell lines. In addition, progastrin enhanced Src tyrosine kinase activity and induced a spatial delocalisation of protein kinase C alpha. Using dominant-negative mutants and pharmacological inhibitors, we showed that the stimulation of Src kinase activity was essential for the regulation of TJs. By contrast, the dissociation of AJs involved phosphatidylinositol 3-kinase, partly through the formation of a complex with protein kinase C alpha. We conclude that separate pathways mediate the disruption of AJs and TJs by progastrin. Either pathway may contribute to the co-carcinogenic role of this prohormone in colorectal carcinoma.
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PMID:Adherens junctions and tight junctions are regulated via different pathways by progastrin in epithelial cells. 1261 62

Adhesion of blood platelets to fibrillar collagens plays a crucial role in haemostasis. Collagen type II is a homotrimeric member of the fibrillar collagen family, whose ability to interact with platelets has been poorly investigated. In this work, we analysed platelet adhesion to the whole collagen type II molecule, as well as to its CNBr peptides. We found that collagen type II is as efficient as collagen type I in supporting platelet adhesion. Platelet binding sites on collagen type II were identified in two different CNBr-derived peptides, CB8 and CB11. The ability of these peptides to support platelet adhesion required the triple helical conformation. Interaction of platelets with CB8 and CB11 peptides was totally dependent on the presence of Mg(2+) ions, and was completely inhibited by the anti-integrin alpha(2)beta(1) antibody P1E6. Upon adhesion to CB8 and CB11, a significant increase in intracellular protein tyrosine phosphorylation was observed. The pattern of tyrosine phosphorylated proteins in CB8- and CB11-adherent platelets was very similar to that observed in platelets adherent to the whole collagen molecule. By immunoprecipitation experiments, we identified two substrates that were tyrosine phosphorylated in adherent platelets as the tyrosine kinase Syk and the PLCgamma2 isozyme. By contrast, platelet adhesion to CB8 and CB11 did not promote tyrosine phosphorylation of FcR gamma-chain. Finally, we found that collagen type II, but not the CNBr-derived peptides, was able to induce cell aggregation associated to protein tyrosine phosphorylation when added to a platelet suspension. These results identify the CNBr peptides from collagen type II CB8 and CB11 as ligands for platelet integrin alpha(2)beta(1), and recognise their ability to support platelet adhesion and activation.
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PMID:Platelet interaction with CNBr peptides from type II collagen via integrin alpha2beta1. 1267 53

Collagen stimulates platelet activation through a tyrosine kinase-based pathway downstream of the glycoprotein VI (GPVI)-Fc receptor (FcR) gamma-chain complex. Genetic ablation of FcR gamma-chain results in a complete inhibition of aggregation to collagen. In contrast, a steady increase in light transmission is induced by collagen in phospholipase Cgamma2-deficient (PLCgamma2-/-) platelets in a Born aggregometer, indicating a weak level of activation. This increase is inhibited partially in the presence of an alpha2beta1-blocking antibody or an alphaIIbbeta3 antagonist and completely by a combination of the 2 inhibitors. It is also abolished by the Src kinase inhibitor PP1 and reduced in the presence of the phosphatidylinositol (PI) 3-kinase inhibitor wortmannin. The GPVI-specific agonists convulxin and collagen-related peptide (CRP) also stimulate weak aggregation in PLCgamma2-/- platelets, which is inhibited by wortmannin and PP1. Collagen and CRP stimulate tyrosine phosphorylation of PLCgamma1 at its regulatory site, Tyr 783, in murine but not in human platelets through a Src kinase-dependent pathway. Adhesion of PLCgamma2-/- platelets to a collagen monolayer is severely reduced at a shear rate of 800 s-1, relative to controls, whereas it is abolished in FcR gamma-chain-/- platelets. These results provide strong evidence that engagement of GPVI stimulates limited integrin activation in PLCgamma2-/- platelets via PLCgamma1 and PI3-kinase.
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PMID:Murine GPVI stimulates weak integrin activation in PLCgamma2-/- platelets: involvement of PLCgamma1 and PI3-kinase. 1273 Jan 18

Adhesion molecules, although catalytically inactive, are able to translate environmental cues into complex intracellular signals. They can do this by associating with tyrosine kinase receptors for growth factors, which can prime, integrate or feedback adhesion-based signals. Recent results show that reciprocal crosstalk between the two systems is only one facet of such a collaboration, and that unconventional and alternative hierarchies can be established in which, on the one hand, cell adhesion can trigger ligand-independent activation of growth factor receptors, and, on the other, growth factors can induce adhesion molecules to propagate adhesion-independent signals.
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PMID:Interactions between growth factor receptors and adhesion molecules: breaking the rules. 1451 91

1. Neutrophil adhesion regulates a number of processes involved in the pathogenesis of inflammatory diseases including rheumatoid arthritis. Neutrophil destructive potential can be modulated by adhesion, allowing alteration of inflammatory cell behaviour while preserving antimicrobial defences. beta(2)-Integrin-mediated neutrophil adhesion to albumin-coated latex beads (ACLB) allows modulation of integrin clustering and ligation and analysis of the effects of adhesion on neutrophil responses. Tumour necrosis factor-alpha (TNF alpha) enhanced neutrophil binding of different diameter ACLB equally, by almost four-fold, and independently of bead size. Adhesion of neutrophils to ACLB caused a size-dependent generation and release of O(2)(-) and also potentiated TNF alpha-induced O(2)(-) release. 2. Binding of ACLB was not affected by disruption of cytoskeletal integrity with nocodazole or cytochalasin D or following blockade of tyrosine kinase activity. In contrast, tyrosine phosphorylation and an intact cytoskeleton were essential for adhesion- and cytokine-induced O(2)(-) release from neutrophils. Inhibition of adhesion- and cytokine-induced O(2)(-) release by 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazol[3,4-d]pyrimidine (PP2) indicated that a Src-family tyrosine kinase was the principal regulatory pathway mediating this response in neutrophils, a distal role for p38 MAPK was revealed by use of SB203580. 3. Tyrosine phosphorylation of c-Fgr, a Src-family tyrosine kinase, occurred following ACLB adhesion and exposure to TNF alpha, and was susceptible to inhibition by PP2. We suggest that activation of the key regulatory enzyme c-Fgr is achieved following ligation of a critical threshold of integrins following binding of large (>3 microM) ACLB.
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PMID:A critical 'threshold' of beta 2-integrin engagement regulates augmentation of cytokine-mediated superoxide anion release. 1500 1

ARAP3 is a GTPase activating protein (GAP) for Rho and Arf GTPases that is implicated in phosphoinositide 3-kinase (PI 3-kinase) signalling pathways controlling lamellipodia formation and actin stress fibre assembly. We have identified ARAP3 as a phosphorylated target of protein tyrosine kinases. In cells, ARAP3 was tyrosine phosphorylated when co-expressed with Src-family kinases (SFKs), upon stimulation with growth factors and during adhesion to the extracellular matrix (ECM) substrate fibronectin. Adhesion-induced phosphorylation of ARAP3 was suppressed by selective inhibitors of Src-family kinases and PI 3-kinase and by a Src dominant interfering mutant. Inducible expression of ARAP3 in HEK293 epithelial cells resulted in increased cell rounding, membrane process formation and cell clustering on ECM substrates. In contrast, ARAP3 dramatically slowed the kinetics of cell spreading on fibronectin but had no effect on cell adhesion. These effects of ARAP3 required a functional Rho GAP domain and were associated with reduced cellular levels of active RhoA and Rac1 but did not require the sterile alpha motif (SAM) or Arf GAP domains. Mutation of two phosphorylation sites, Y1399 and Y1404, enhanced some ARAP3 activities, suggesting that ARAP3 may be negatively regulated by phosphorylation on these tyrosine residues. These results implicate ARAP3 in integrin-mediated tyrosine kinase signalling pathways controlling Rho GTPases and cell spreading.
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PMID:ARAP3 is transiently tyrosine phosphorylated in cells attaching to fibronectin and inhibits cell spreading in a RhoGAP-dependent manner. 1554 19

Glycosphingolipids (GSLs) at the cell surface membrane are associated or complexed with signal transducers (Src family kinases and small G-proteins), tetraspanins, growth factor receptors, and integrins. Such organizational framework, defining GSL-modulated or -dependent cell adhesion, motility, and growth, is termed "glycosynapse" (Hakomori, S., and Handa, K. (2002) FEBS Lett. 531, 88-92; Hakomori, S. (2004) Ann. Braz. Acad. Sci. 76, 553-572). We describe here the functional organization of the glycosynaptic microdomain, and the mechanisms for control of cell motility and invasiveness, in normal bladder epithelial HCV29 cells versus highly invasive bladder cancer YTS1 cells, both derived from transitional epithelia. (i) Ganglioside GM2, but not GM3 or globoside, interacted specifically with tetraspanin CD82, and such a complex inhibited hepatocyte growth factor (HGF)-induced activation of Met tyrosine kinase in a dose-dependent manner. (ii) Depletion of GM2 in HCV29 cells by treatment with D-threo-1-phenyl-2-palmitoylamino-3-pyrrolidino-1-propanol (P4), or reduction of CD82 expression by RNA interference, significantly enhanced HGF-induced Met tyrosine kinase and cell motility. (iii) In contrast, YTS1 cells, lacking CD82, displayed HGF-independent activation of Met tyrosine kinase and high cell motility. Transfection of the CD82 gene to YTS1 inhibited HGF dose-dependent Met tyrosine kinase activity and cell motility, due to formation of the GM2-CD82 complex. (iv) Adhesion of YTS1 or YTS1/CD82 cells to laminin-5-coated plates, as compared with noncoated plates, strongly enhanced Met activation, and the degree of activation was further increased in association with GSL depletion by P4. Laminin-5-dependent Met activation was minimal in HCV29 cells. These findings indicate that GSL, particularly GM2, forms a complex with CD82, and that such complex interacts with Met and thereby inhibits HGF-induced Met tyrosine kinase activity, as well as integrin to Met cross-talk.
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PMID:Ganglioside GM2-tetraspanin CD82 complex inhibits met and its cross-talk with integrins, providing a basis for control of cell motility through glycosynapse. 1721 49


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