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Results for “Cell Adhesion”

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At least 127 records · Page 7Linked to original sources

PubMed2005

The role of the cytoskeleton in differentially regulating pressure-mediated effects on malignant colonocyte focal adhesion signaling and cell adhesion.

Increased extracellular pressure stimulates colon cancer cell adhesion by activating focal adhesion kinase (FAK) and Src. We investigated the role of the cytoskeleton in pressure-induced inside-out FAK and Src phosphorylation and pressure-stimulated adhesion. We perturbed actin polymerization with phalloidin, cytochalasin D and latrunculin B, and microtubule organization with colchicine and paclitaxol. We compared the effects of these agents on pressure-induced SW620 and human primary colon cancer cell adhesion and inside-out FAK/Src activation with outside-in adhesion-dependent FAK/Src activation. Cells pretreated with cytoskeletal inhibitors were subjected to 15 mmHg increased pressure and allowed to adhere to collagen I coated plates or prevented from adhesion to pacificated plates for 30 min. Phalloidin, cytochalasin D, latrunculin B and colchicine pretreatment completely prevented pressure-stimulated and significantly inhibited basal SW620 cell adhesion. Taxol did not inhibit pressure-induced colon cancer cell adhesion, but significantly lowered basal adhesion. Cytochalasin D and colchicine had similar effects in pressure-stimulated primary human malignant colonocytes. Phalloidin, cytochalasin D, latrunculin B and colchicine prevented pressure-induced SW620 FAK phosphorylation but not Src phosphorylation. FAK phosphorylation in response to collagen I adhesion was significantly attenuated but not completely prevented by these inhibitors. Although Src phosphorylation was not increased on adhesion, the cytoskeleton disrupting agents significantly lowered basal Src phosphorylation in adherent cells. These results suggest that both cytoskeleton-dependent FAK activation and cytoskeleton-independent Src activation may be required for extracellular pressure to stimulate colon cancer cell adhesion. Furthermore, the cytoskeleton plays a different role in pressure-activated FAK and Src signaling than in FAK and Src activation in adherent cells. We, therefore, hypothesize that cytoskeletal interactions with focal adhesion signals mediate the effects of extracellular pressure on colon cancer cell adhesion.

Cell Adhesion↗

PubMed1995

Mast cells induce T-cell adhesion to human fibroblasts by regulating intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 expression.

The capacity of mast cell products to mediate T-cell adhesion to fibroblasts was explored using heterotypic coculture systems or by exposing fibroblasts to mast-cell-conditioned media (MCCM), prepared by degranulating mast cells with calcium ionophore. Experimental results indicated that fibroblasts exposed to MCCM for 24 h bound fivefold more T cells than control fibroblasts. Binding was inhibited with intercellular adhesion molecule-1 (ICAM-1) or vascular cell adhesion molecule-1 (VCAM-1) neutralizing antibodies. Enzyme-linked immunosorbent assay and fluorescence-activated cell sorter analysis revealed that fibroblasts exposed to MCCM markedly increased ICAM-1 and VCAM-1 surface expression by 4 h, with levels maximal at 16 h and returning toward baseline by 48 h. A dose-dependent response of ICAM-1 and VCAM-1 expression was noted using serial dilutions of MCCM or by altering the ratio of degranulated mast cells cocultured with fibroblasts. Similar results were obtained using human fibroblasts derived from the dermis, synovium, and lung, although lung fibroblasts were generally less responsive. Northern analysis confirmed that MCCM regulated ICAM-1 and VCAM-1 expression at the mRNA level. In summary, mast cell products stimulated fibroblast surface expression, steady-state mRNA levels, and functional expression of ICAM-1 and VCAM-1. Experimental data suggest that mast-cell-derived tumor necrosis factor-alpha may be in large part responsible for these observations, although further studies using human mast cells will be required. Using a skin-equivalent organotypic coculture model with fibroblasts admixed with mast cells, we observed increased ICAM-1 expression in both keratinocytes and fibroblasts after activation of the mast cells.

Adult↗

PubMed1991

Tumor cell adhesion to endothelial cells: endothelial leukocyte adhesion molecule-1 as an inducible adhesive receptor specific for colon carcinoma cells.

Activation of endothelial cells by the two inflammatory mediators interleukin-1 (IL-1) and tumor necrosis factor strongly increases tumor cell adhesion. We describe antibody inhibition studies showing that the endothelial leukocyte adhesion molecule-1 (ELAM-1), a cell-surface glycoprotein selectively expressed by cytokine-activated endothelial cells and responsible for neutrophil adhesion, is the major, if not the only, mediator of colon carcinoma cell adhesion to activated endothelial cells. Among the different tumor cell lines tested, seven colon carcinoma cell lines were sensitive to ELAM-1 antibodies. Adhesion of melanoma, osteosarcoma, and lung, cervix, or kidney carcinoma cell lines to IL-1-treated endothelial cells was not affected by the ELAM-1 antibody. This result suggests that ELAM-1 is selectively recognized by colon carcinoma cells and that adhesion of tumor cells to activated endothelial cells could be mediated by different and specific mechanisms.

Antibodies, Monoclonal↗

PubMed2003

Activation of Rac and tyrosine phosphorylation of cytokine receptors induced by cross-linking of integrin alpha4beta1 and cell adhesion in hematopoietic cells.

Adhesion of hematopoietic cells, mainly through alpha4beta1 and alpha5beta1 integrins, to the bone marrow microenvironment may play important roles in regulation of hematopoiesis. However, the mechanisms for signaling, outside-in signaling, have largely remained to be established. We demonstrate here that cross-linking of alpha4beta1 by anti-alpha4 antibody induces tyrosine phosphorylation of Pyk2, Shc, and Cbl as well as binding of the adaptor protein CrkL with Cbl in a murine hematopoietic cell line, 32D/EpoR-Wt. Furthermore, cross-linking of alpha4beta1 induced activation of the Rho family small GTPase Rac, which was enhanced by induced overexpression of CrkL and was inhibited by the phosphatidylinositol 3(')-kinase (PI3K) inhibitor LY294002. In addition, adhesion of 32D/EpoR-Wt cells to immobilized H-296, a recombinant fibronectin peptide specific for alpha4beta1, induced tyrosine phosphorylation of Jak2, the erythropoietin receptor (EpoR), and the IL-3 receptor beta subunit as well as Pyk2, Shc, and Cbl. Tyrosine phosphorylation of Jak2 and EpoR was also induced in a human leukemic cell line, UT-7, by adhesion to immobilized H-296. However, adhesion of 32D/EpoR-PM4 cells, expressing the W282R mutant EpoR defective in coupling with Jak2, to immobilized H-296 failed to induce tyrosine phosphorylation of the mutant EpoR. These results implicate CrkL in PI3K-dependent activation of Rac by outside-in signaling from alpha4beta1 and suggest that adhesion through alpha4beta1 further activates cytokine receptor-associated Jak2 to induce phosphorylation of these receptors.

Adaptor Proteins, Signal Transducing↗

PubMed2004

Regulation of squamous cell carcinoma antigen production by E-cadherin mediated cell-cell adhesion in squamous cell carcinoma cell line.

Squamous cell carcinoma antigen (SCCA) is a useful tumor marker for diagnosis and management of squamous cell carcinoma. It is well known that cell-cell adhesion is important for progression of cancer. However, it is not clarified whether cell-cell adhesion affects SCCA production in squamous cell carcinoma. The present study was, therefore, undertaken to investigate whether E-cadherin-mediated cell-cell adhesion affects SCCA production in squamous cell carcinoma of the uterine cervix. SKG-IIIa cells or CaSki cells, cervical squamous cell carcinoma cell lines, were treated with anti-E-cadherin antibodies (1 microg/ml) up to 72 h. The cells were dissociated, and SCCA content in the cytosol and SCCA mRNA levels were significantly decreased compared to the control group treated with mouse IgG. Secondly, the signaling pathway for SCCA production mediated by E-cadherin was examined. Phosphatidylinositol (PI) 3-kinase is a well-known mediator of E-cadherin-mediated biological events. The treatment with a PI 3-kinase inhibitor suppressed SCCA production in SKG-IIIa cells. It is concluded that E-cadherin mediated cell-cell adhesion maintains SCCA production through PI 3-kinase in squamous cell carcinoma.

Antibodies, Neoplasm↗

PubMed2006

Regulation of cell adhesion by protein-tyrosine phosphatases: II. Cell-cell adhesion.

Cell-cell adhesion is critical to the development and maintenance of multicellular organisms. The stability of many adhesions is regulated by protein tyrosine phosphorylation of cell adhesion molecules and their associated components, with high levels of phosphorylation promoting disassembly. The level of tyrosine phosphorylation reflects the balance between protein-tyrosine kinase and protein-tyrosine phosphatase activity. Many protein-tyrosine phosphatases associate with the cadherin-catenin complex, directly regulating the phosphorylation of these proteins, thereby affecting their interactions and the integrity of cell-cell junctions. Tyrosine phosphatases can also affect cell-cell adhesions indirectly by regulating the signaling pathways that control the activities of Rho family G proteins. In addition, receptor-type tyrosine phosphatases can mediate outside-in signaling through both ligand binding and dimerization of their extracellular domains. This review will discuss the role of protein-tyrosine phosphatases in cell-cell interactions, with an emphasis on cadherin-mediated adhesions.

Animals↗

PubMed1981

Studies on cell adhesion and recognition. II. The kinetics of cell adhesion and cell spreading on surfaces coated with carbohydrate-reactive proteins (glycosidases and lectins) and fibronectin.

The kinetics of cell attachment and cell spreading on the coated surfaces of two classes of carbohydrate-reactive proteins, enzymes and lectins, have been compared with those on fibronectin-coated surfaces with the following results: (a) A remarkable similarity between the kinetics of cell attachment to fibronectin-coated and glycosidase-coated surfaces was found. In contrast, cell attachment kinetics induced by lectin- and galactose oxidase-coated surfaces, in general, were strikingly different from those on fibronectin and glycosidase surfaces. The distinction between fibronectin- or glycosidase- and lectin- or galactose oxidase (an enzyme with lectin-type characteristics)-coated surfaces was further supported by the finding that cytochalasin B and EDTA inhibited cell attachment to fibronectin- and glycosidase-coated surfaces but not lectin-coated surfaces. (b) Fibronectin, if labeled and added to a cell suspension, showed only low or negligible interaction with the cell surface. However, fibronectin absorbed on plastic surfaces showed a high cell-attaching activity. It is assumed that fibronectin coated on plastic surfaces may form polyvalent attachment sites in contrast to its lower valency in aqueous solution. (c) Various inhibitors of cell attachment to both fibronectin-, galactose oxidase-, and lectin-coated surfaces were effective only during the first few minutes of the adhesion assay, after which time the attached cells became insensitive to the inhibitors. It is suggested that the initial specific recognition on either lectin-type or fibronectin-type surfaces is followed by an active cell-dependent attachment process. The primary role of the adhesion surface is to stimulate the cell-dependent attachment response. (d) Cells attached on tetravalent concanavalin A (Con A) spread very rapidly and quantitatively, whereas divalent succinyl Con A and monovalent Con A were effective stimulators of cell attachment but not cell spreading. Cross-linking of succinyl Con A restored the cell spreading activity. Tetravalent Con A surfaces specifically bind soluble glycoproteins, whereas succinyl Con A has a greatly reduced ability to bind the same glycoproteins. These results suggest that cross-linking of cell surface glycoproteins by the multivalent adhesive surface may trigger the cellular reaction leading to cell spreading.

Animals↗

PubMed2001

Chlamydia trachomatis infection induces mucosal addressin cell adhesion molecule-1 and vascular cell adhesion molecule-1, providing an immunologic link between the fallopian tube and other mucosal tissues.

The development of a protective vaccine against the sexually transmitted disease caused by Chlamydia trachomatis may prevent complications associated with insidious infection. Vaccination via the vaginal route may not be practical, and other routes should be investigated. To this end, the adhesion molecules induced on the fallopian tube endothelium during infection with C. trachomatis were characterized. Adhesion molecules were identified in fallopian tube biopsy specimens cultured with 5 x 10(6) infection-forming units of C. trachomatis serovar E. Frozen sections were prepared from these tissues and were stained by immunohistochemical techniques. Infection with live, but not UV-inactivated, C. trachomatis induced a significant increase in levels of vascular cell adhesion molecule-1 and the mucosal addressin cell adhesion molecule-1 but not of other adhesion molecules. Therefore, infection with C. trachomatis induces adhesion molecules that are associated with other mucosal tissues and inflammatory sites, which suggests that mucosal routes of immunization may be effective.

Biopsy↗

PubMed2001

Vascular endothelial growth factor, platelet endothelial cell adhesion molecule-1 and vascular cell adhesion molecule-1 in the follicular fluid of patients undergoing IVF.

BACKGROUND: The aim of our study was to measure concentrations of vascular endothelial growth factor (VEGF), platelet endothelial cell adhesion molecule-1 (PECAM-1) CD31 and vascular cell adhesion molecules (VCAM-1) in the follicular fluid of women treated with assisted reproduction technology to determine whether these proteins might be outcome markers. METHODS: Follicular fluid was collected from 75 patients < or =40 years undergoing oocyte retrieval procedures at our tertiary hospital during 1997 and 1998: 50 with tubal disease, 12 with endometriosis, and 13 whose partners had been diagnosed with severe oligoasthenoteratozoospermia. This retrospective analysis considered age and information about treatment and outcome for all these women who had undergone fewer than three assisted reproduction attempts. RESULTS: Nineteen women became pregnant (defined by human chorionic gonadotrophin concentrations and embryonic cardiac activity 1 month after follicular aspiration); 56 did not. Women did not differ significantly in their follicular fluid concentrations of VEGF, sCD31 and VCAM-1 according to cause of infertility, or assisted reproduction outcome, or age. Follicular fluid concentrations of VEGF were significantly correlated with the number of gonadotrophin ampoules administered (P < 0.012), and follicular fluid concentrations of sVCAM-1 with the fertilization rate (P < 0.01). Follicular fluid concentrations of VEGF and sVCAM-1 were also correlated (P < 0.007). CONCLUSIONS: Our results do not suggest that VEGF, CD31, or sVCAM-1 in follicular fluid predict assisted reproduction outcome, especially among patients < or =40 years old. The correlation of a high fertilization rate and sVCAM-1 in follicular fluid suggests that sVCAM-1 might be a marker of fertilization.

Abortion, Spontaneous↗

PubMed2000

Lateral clustering of cadherin-4 without homophilic interaction: possible involvement in the concentration process at cell-cell adhesion sites as well as in the cell adhesion activity.

It is thought that the concentration of classic cadherins at cell-cell adhesion sites is essential for generating strong cell-cell adhesion activity, but the mechanism is not well understood. To clarify the structural basis of the concentration process and the cell adhesion activity, we constructed various mutants of cadherin-4 and examined the adhesion properties of the transfectants. A deletion mutant lacking the entire cytoplasmic domain had weak, but significant Ca(2+)-dependent cell adhesion activity. Interestingly, the deletion mutant showed intrinsic cluster formation in the absence of cell-cell adhesion, possible lateral cluster formation. The cytoplasmic domain-deleted cadherin-4 containing the mutation of Trp-2 to Ala, which is known to inhibit the strand dimer formation required for the cell-cell adhesion, retained the possible activity of lateral cluster formation, supporting this notion. These results suggest that the extracellular domain has intrinsic activity of lateral cluster formation. Indeed, deletion of a cadherin repeat in the extracellular domain significantly reduced or abolished the lateral cluster formation as well as the concentration of cadherin-4 at cell-cell contact sites and cell adhesion activity. When transfectants of the cytoplasmic domain-deleted cadherin-4 made cell-cell contact and formed intimate cell-cell adhesion, the lateral clusters of cadherin-4 initially gathered at cell-cell contact sites, and a smooth linear concentration was gradually formed along the cell-cell adhesion interface. The results suggest that the lateral cluster formation is involved in the concentration process of cadherin-4 at cell-cell adhesion sites, hence in the strong cell adhesion activity of cadherin-4 as well.

Amino Acid Substitution↗

PubMed2002

Function of linear and cyclic RGD-containing peptides in osteoprogenitor cells adhesion process.

Cell adhesion directly influences cell growth, differentiation and migration as well as morphogenesis, integrity and repair. The extracellular matrix (ECM) elaborated by osteoblast cells constitutes a regulator of the cell adhesion process and then of the related phenomenon. These regulatory effects of ECM are mediated through integrins and some of them are able to bind RGD sequences. The aim of this study was to determine the role of the sequence and the structure of RGD-containing peptides (linear and cyclic) as well as their role in the cell adhesion process. Cell adhesion assays onto ECM proteins coated surfaces were performed using a range of linear and cyclic RGD-containing peptides. We showed a different human osteoprogenitor cell adhesion according to the coating for ECM proteins and for RGD-peptides. Inhibition assays using peptides showed different responses depending on the coated protein. Depending on the amino-acid sequence and the structure of the peptides (cyclic linear), we observed 100% inhibition of cell adhesion onto vitronectin. These results suggest the importance of sequence, structure and conformation of the peptide, which may play a crucial function in the ligand/receptor interaction and/or in the stability of the interaction.

Adult↗

PubMed2004

Ligand stimulation of CD155alpha inhibits cell adhesion and enhances cell migration in fibroblasts.

CD155 (poliovirus receptor) localizes in cell-matrix adhesions and cell-cell junctions, but its role in the regulation of cell adhesion and cell motility has not been investigated. We identified a conserved immunoreceptor tyrosine-based inhibitory motif (ITIM) in the cytoplasmic domain of human CD155alpha. The ITIM was tyrosine-phosphorylated upon binding of anti-CD155 monoclonal antibody D171, poliovirus, and DNAM-1 (CD226) to human CD155alpha, and recruited SH2-domain-containing tyrosine phosphatase-2 (SHP-2). After CD155alpha stimulation with its ligands, cell adhesion was inhibited and cell motility was enhanced, effects that were associated with the phosphorylation of ITIM by Src kinases and accompanied by dephosphorylation of focal adhesion kinase and paxillin. These effects were abolished by introducing a point-mutation in Y398F into the ITIM of CD155alpha and by coexpression of a dominant negative SHP-2 mutant with CD155alpha. These results suggest that CD155alpha plays a role in the regulation of cell adhesion and cell motility.

Amino Acid Sequence↗

PubMed1997

Human peripheral blood eosinophils express a functional c-kit receptor for stem cell factor that stimulates very late antigen 4 (VLA-4)-mediated cell adhesion to fibronectin and vascular cell adhesion molecule 1 (VCAM-1).

We evaluated mature peripheral blood eosinophils for their expression of the surface tyrosine kinase, c-kit, the receptor for the stromal cell-derived cytokine, stem cell factor (SCF). Cytofluorographic analysis revealed that c-kit was expressed on the purified peripheral blood eosinophils from 8 of 8 donors (4 nonatopic and 4 atopic) (mean channel fluorescence intensity 2.0- 3. 6-fold, average 2.8 +/- 0.6-fold, greater than the negative control). The uniform and selective expression of c-kit by eosinophils was confirmed by immunohistochemical analysis of peripheral blood buffy coats. The functional integrity of c-kit was demonstrated by the capacity of 100 ng/ml (5 nM) of recombinant human (rh) SCF to increase eosinophil adhesion to 3, 10, and 30 microg/ml of immobilized FN40, a 40-kD chymotryptic fragment of plasma fibronectin, in 15 min by 7.7 +/- 1.4-, 5.3 +/- 3.3-, and 5.4 +/- 0. 2-fold, respectively, and their adhesion to 0.1, 0.5, and 1.0 microg/ml vascular cell adhesion molecule-1 (VCAM-1), by 12.7 +/- 9. 2-, 3.8 +/- 2.5-, and 1.7 +/- 0.6-fold, respectively. The SCF-stimulated adhesion occurred without concomitant changes in surface integrin expression, thereby indicating an avidity-based mechanism. rhSCF (100 ng/ml, 5 nM) was comparable to rh eotaxin (200 ng/ml, 24 nM) in stimulating adhesion. Cell adhesion to FN40 was completely inhibited with antibodies against the alpha4 and beta1 integrin subunits, revealing that the SCF/c-kit adhesion effect was mediated by a single integrin heterodimer, very late antigen 4 (VLA-4). Thus, SCF represents a newly recognized stromal ligand for the activation of eosinophils for VLA-4-mediated adhesion, which could contribute to the exit of these cells from the blood, their tissue localization, and their prominence in inflammatory lesions.

Cell Adhesion↗

PubMed2001

CD98 induces LFA-1-mediated cell adhesion in lymphoid cells via activation of Rap1.

CD98 is a multifunctional heterodimeric membrane protein involved in the regulation of cell adhesion as well as amino acid transport. We show that CD98 cross-linking persistently activates Rap1 GTPase in a LFA-1-dependent manner and induces LFA-1/ICAM-1-mediated cell adhesion in lymphocytes. Specific phosphatidylinositol-3-kinase (PI3K) inhibitors suppressed both LFA-1 activation and Rap1GTP generation, and abrogation of Rap1GTP by retroviral over-expression of a specific Rap1 GTPase activating protein, SPA-1, totally inhibited the LFA-1/ICAM-1-mediated cell adhesion. These results suggest that CD98 cross-linking activates LFA-1 via the PI3K signaling pathway and induces accumulation of Rap1GTP in a LFA-1-dependent manner, which in turn mediates the cytoskeleton-dependent cell adhesion process.

Androstadienes↗

PubMed1998

Msh homeobox genes regulate cadherin-mediated cell adhesion and cell-cell sorting.

Msx-1 and Msx-2 are two closely related homeobox genes expressed in cephalic neural crest tooth buds, the optic cup endocardial cushions, and the developing limb [Hill and Davidson, 1991; Monaghan et al., 1991; Robert et al., 1991]. These sites correspond to regions of active cell segregation and proliferation under the influence of epithelial-mesenchymal cell interactions [Brown et al., 1993; Davidson et al., 1991], suggesting that Msx-1 and Msx-2 regulate cell-cell interactions. We have investigated the potential relationship between expression of the Msh homeobox genes (Msx-1 and Msx-2) and cadherin-mediated cell adhesion and cell sorting. We report that cell lines stably expressing Msx-1 or Msx-2 differentially sort on the basis of Msh gene expression. We demonstrate in vitro that initial cell aggregation involves calcium-dependent adhesion molecules (cadherins) and that Msh genes regulate cadherin-mediated adhesion. These results support the hypothesis that Msh genes play a role in the regulation of cell-cell adhesion and provide a link between the genetic phenomena of homeobox gene expression and cellular events involved in morphogenesis, including cell sorting and proliferation.

Animals↗

PubMed2003

Platelet endothelial cell adhesion molecule in cell signaling and thrombosis.

Platelet endothelial cell adhesion molecule (PECAM-1) is a member of the superfamily of immunoglobulins. This cell adhesion molecule has been implicated to mediate the adhesion and trans-endothelial migration of T lymphocytes/monocytes into the vascular wall, a critical step in the initiation of atherogenesis. Current thinking, however, posits that PECAM-1 by virtue of being a scaffolding molecule may well play a role in several signal transduction reactions. As a consequence, this cell adhesion molecule may be responsible for several biological and pathophysiological functions such as thrombosis, and inflammation. Evidence has also been put forward for a potential role of PECAM-1 in apoptosis and atherosclerosis. This article focuses on the structure of PECAM-1 and its role in intracellular signaling and implications in health and disease.

Apoptosis↗

PubMed1990

Differential effects of the cytoplasmic domains of cell adhesion molecules on cell aggregation and sorting-out.

Cell adhesion molecules (CAMs) are cell surface glycoproteins that play important roles in morphogenesis and histogenesis, particularly in defining discrete borders between cell populations. Previous studies have suggested that the cytoplasmic domains of CAMs play a significant role in their adhesion properties. These domains may also be involved in regulating other cellular interactions, such as those involved in the sorting-out of cells to form tissues. In the present studies, we have compared the effects of replacing the cytoplasmic domain of one CAM with that of another CAM of different homophilic binding specificity on cell adhesion and cell sorting-out. The molecules studied were liver CAM (L-CAM) and the neural CAM (N-CAM) sd polypeptide. One cDNA was constructed that encodes a chimeric molecule composed of the extracellular domain of L-CAM and the cytoplasmic plus transmembrane domains of the sd polypeptide of chicken N-CAM (called L/N-CAM). Another was constructed encoding a truncated L-CAM missing the last 50 residues of the cytoplasmic domain. Permanently transfected lines of mouse L cells were obtained expressing the truncated L-CAM ("L-L-50 cells") or the chimeric L/N-CAM ("L-L/N cells") and were compared with cells expressing intact L-CAM ("L-L cells"). Immunoblotting and ELISA analyses demonstrated that these various cell lines expressed similar amounts of CAMs at the cell surface. Aggregation of L-L and L-L/N cells occurred at similar rates in short-term aggregation assays and was inhibited by antibodies to the extracellular L-CAM binding domain. In contrast, L-L-50 cells did not aggregate. Incubation of transfected cells with cytochalasin D, which disrupts microfilaments, markedly inhibited aggregation of L-L cells but had no effect on L-L/N cell aggregation. Mixed L-L and L-L/N cells co-aggregated in short-term assays; in the longer-term sorting-out assays, however, they behaved differently: L-L cells sorted out from both L-L/N and untransfected cells, whereas L-L/N cells did not sort out from untransfected cells. These studies not only suggest that interactions of cytoplasmic domains of different CAMs with the cytoskeleton can modulate cell adhesion but also suggest that specific interactions with certain cytoskeletal components are required for events such as cell sorting and cell patterning.

Animals↗

PubMed2004

Statins reduce oxidized low-density lipoprotein levels, but do not alter soluble intercellular cell-adhesion molecule-1 and vascular cell-adhesion molecule-1 levels in subjects with hypercholesterolaemia.

ICAM-1 (intercellular cell-adhesion molecule-1) and VCAM-1 (vascular cell-adhesion molecule-1) are cell-adhesion molecules that have an essential role in monocyte recruitment. In the present study we have investigated (i) whether statins reduce soluble levels of ICAM-1 (sICAM-1) and VCAM-1 (sVCAM-1), and the relationship between resistance of LDL (low-density lipoprotein) to in vitro oxidation and sICAM-1 and sVCAM-1 levels. Whole blood samples were obtained from 55 healthy non-smoking adults (aged 35-65 years) with moderate (LDL-cholesterol, 3.4-4.9 mmol/l) hypercholesterolaemia participating in a randomized double-blinded, 8-week trial comparing pravastatin (40 mg), simvastatin (20 and 80 mg) and placebo. sICAM-1 levels (means+/-S.D.) increased slightly from 12.2+/-4.2 to 13.6+/-4.2 ng/ml with statin therapy, whereas, among placebo-assigned subjects, levels were unchanged (11.8+/-5.0 and 11.8+/-3.9 ng/ml). sVCAM-1 increased from 18.9+/-10.1 to 21.1+/-7.4 ng/ml among those on active therapy and slightly declined with placebo assignment (19.8+/-8.8 to 19.4+/-6.4 ng/ml). Lag times increased with statin therapy from 74.3+/-39.8 min to 98.3+/-57.8 min ( P =0.003), and were unchanged in the placebo group (from 103.1+/-61.1 to 90.8+/-65.9 min; P =0.48). There were no significant changes between statin and placebo therapy for sICAM-1, sVCAM-1 or lag times ( P =0.09, 0.16 and 0.067 respectively). Changes in sICAM-1 and sVCAM-1 were not correlated with the change in lag times. In contrast with the known effects of oxidized LDL on gene activation of ICAM-1 and VCAM-1, lag times did not correlate with sICAM-1 and sVCAM-1. Statin therapy improved lag times, but has no effect on sICAM-1 or sVCAM-1 levels.

Adult↗