SEARCH · Search PubMed

Results for “Vitronectin”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,495 records · Page 83Linked to original sources

PubMed1994

Co-expression of endothelial cell and macrophage antigens in Kaposi's sarcoma cells.

The histopathogenesis of Kaposi's sarcoma (KS) was investigated using immunocytochemistry in 12 skin biopsies obtained from two AIDS patients, nine patients with the classic form, and one organ-transplant patient. KS cells revealed a peculiar antigenic profile, being characterized by co-expression of endothelial and macrophage markers. KS cells were stained for von Willebrand factor (vWF); for vascular endothelial (VE) cadherin, an endothelial specific adhesion molecule; and for PECAM/CD31. In addition, they expressed the macrophage antigens PAM-1, CD68, and CD14, and were positive for vitronectin receptor and alpha-1,5,6/beta-1 integrins. KS cells were weakly stained for ICAM-1 in 6 of 12 cases and were negative for VCAM-1 and E-selectin.

Acquired Immunodeficiency Syndrome↗

PubMed2005

Type XIII collagen expression is induced during malignant transformation in various epithelial and mesenchymal tumours.

Little information is available on the expression of transmembrane type XIII collagen in human diseases. The present study has investigated the expression of this collagen in cancer, in particular during malignant transformation. By combining the tissue microarray technique with in situ hybridization, a consistent pattern of clearly increased type XIII collagen mRNA expression was found in the stromal compartment of epithelial tumours and throughout mesenchymal tumours. Slightly elevated mRNA expression was observed in dysplastic samples and in malignant epithelial cells. It is also demonstrated that factors secreted into the culture medium by tumour cells, in particular the growth factor TGF-beta, contribute to the induction of type XIII collagen expression, and trigger concomitantly a profound phenotypic and morphological transition of cultured primary fibroblasts. Reciprocally, type XIII collagen may alter the growth milieu of malignant cells as the soluble type XIII collagen ectodomain influenced the adherence and spreading of cells cultured on vitronectin-rich matrix. It is proposed that malignant transformation stimulates the expression of type XIII collagen, particularly in the tumour stroma and to a lesser extent in the epithelium, and that this high type XIII collagen expression may contribute to tumour progression and behaviour by modulating cell-matrix interactions.

Cell Adhesion↗

PubMed2006

Protein nanoarray on Prolinker surface constructed by atomic force microscopy dip-pen nanolithography for analysis of protein interaction.

Protein nanoarrays are addressable ensembles of nano-scale protein domain on solid surfaces. This method can serve as a useful platform for ultraminiaturized bioanalysis. In this study, we investigated single molecular nanopatterning and molecular interaction of proteins that were immobilized on Prolinker surface of gold-coated silicon wafer by using dip-pen nanolithography (DPN) method. Contact force and humidity were optimized at 0.01 nN and 80%, respectively. The domain features of protein nanoarrays were developed at the contact time of 5 s. The optimized conditions for the nanoarray process were applied to create protein nanoarray using integrin alpha(v)beta3 and angiogenin. Constructed protein nanoarrays using integrin alpha(v)beta3 have single molecular monolayer with regular domain shape (height 15 +/- 5 nm). The changed height value due to the single molecular interaction between integrin alpha(v)beta3 and vitronectin was approximately 30 +/- 5 nm on Prolinker surface as measured with atomic force microscopy tip. Taken together, these results suggest that protein nanoarray on Prolinker surface fabricated by well-controlled DPN process can be used to analyze single molecular interaction of protein.

Gold↗

PubMed1993

Fibrinogen binds to heparin: the relationship of the binding of other adhesive proteins to heparin.

The binding of heparin to fibrinogen was characterized. We have used an assay employing heparin coupled to Sepharose CL-6B to show that 125I-fibrinogen binds to heparin in a time-dependent, divalent ion-independent, saturable, and reversible manner. A total of 1.75 mg of fibrinogen could bind to 1 ml of heparin-Sepharose CL-6B with a Kd of 4.03 x 10(-7) M. Binding was completely inhibited by other adhesive proteins including fibronectin, von Willebrand factor (vWF), and vitronectin with IC50s of 7.2-8.8 microM. The binding of 125I-fibrinogen to heparin-Sepharose CL-6B was blocked by a monoclonal antibody (52k-2) and a polyclonal antibody (FK-2). 52k-2 inhibits the binding of vWF, and FK-2 blocks the binding of fibronectin to heparin-Sepharose CL-6B. It is therefore likely that fibrinogen has a heparin-binding site(s) which may have some overlap with those of other adhesive proteins, although the physiological role of the fibrinogen heparin-binding domain is uncertain at present.

Antibodies, Monoclonal↗

PubMed2000

Molecular cloning and functional expression of contortrostatin, a homodimeric disintegrin from southern copperhead snake venom.

Contortrostatin is a unique dimeric disintegrin isolated from southern copperhead snake venom. Through antagonism of integrins alphaIIbbeta3, alpha5beta1, alphavbeta3, and alphavbeta5, contortrostatin inhibits platelet aggregation and disrupts cancer cell adhesion and invasion. We cloned cDNA from a library made from the venom gland cells of Agkistrodon contortrix contortrix using polymerase chain reaction. We found that the contortrostatin gene is part of a precursor composed of proprotein, metalloproteinase, and disintegrin domains. The precursor cDNA is 2027 bp with a 1449-bp open reading frame. The disintegrin domain is 195 bp encoding 65 amino acids. Like other members of the disintegrin family, each subunit of contortrostatin has an RGD site, and the cysteine alignment is conserved. The disintegrin domain of the cDNA has been expressed in a eukaryotic expression system as a homodimeric fusion protein with an immunoglobulin. The recombinant protein is recognized by an antiserum against native contortrostatin in Western blot. Both the native and recombinant proteins bind to integrins alphavbeta3 and alphavbeta5. Like native contortrostatin, the recombinant fusion protein inhibits platelet aggregation, blocks cancer cell adhesion to fibronectin and vitronectin, and prevents invasion of cancer cells through a Matrigel barrier. The success of functional expression not only validates the cDNA cloning of this disintegrin, but also provides adequate material for functional studies of contortrostatin.

Agkistrodon↗

PubMed1993

Altered fibronectin-dependent cell adhesion by PDGF accompanies phenotypic modulation of vascular smooth muscle cells.

PDGF promotes growth of smooth muscle cells (SMCs) and induces morphological changes. We investigated the effects of PDGF on cell-matrix adhesion of SMCs. PDGF reorganized integrin distribution as well as actin filament structure. PDGF-treated cells attached more loosely to fibronectin than non-treated cells. Decreased expression of alpha-actin by PDGF was antagonized by coating culture dishes with fibronectin but not with vitronectin and laminin. The inhibition of cell adhesion by GRGDSP oligopeptide and anti-fibronectin receptor antibody led to the reduction in alpha-actin expression. These results suggest that PDGF may modulate phenotype of SMCs by altering fibronectin-integrin interaction.

Actins↗

PubMed1994

Binding and bioeffects of Ipriflavone on a human preosteoclastic cell line.

Ipriflavone, a synthetic isoflavone derivative, reduces bone resorption by inhibiting osteoclasts activity. In order to evaluate the role of Ipriflavone on osteoclast growth and differentiation, we tested Ipriflavone and its four "in vivo" main metabolites (Metabolites I, II, III, and V) on a clonal population of human osteoclast precursor cells (FLG 29.1). Pharmacological doses of Ipriflavone and Metabolite III were able to inhibit cell proliferation and interleukin 6 release. In co-cultures of FLG 29.1 cells and osteoblastic (Saos-2) cells Ipriflavone at 1 microM dose inhibited the adhesion of FLG 29.1 cells to the osteoblastic monolayer and reduced the immunocytochemical reaction of the vitronectin receptor. Binding studies with tritiated Ipriflavone showed the presence of a single specific binding site, wtih a Kd of about 70 nM and a binding capacity of 8 fmol/10(6) cells. These results demonstrate a direct effect of Ipriflavone and of Metabolite III on the human osteoclast precursor cell line FLG 29.1.

Cell Adhesion↗

PubMed1997

A new mechanism of bone destruction in rheumatoid arthritis: synovial fibroblasts induce osteoclastogenesis.

Bone-resorbing multinucleated cells were efficiently formed in primary culture of cells isolated from synovial tissues of patients with rheumatoid arthritis in 2-3 weeks in the presence of 1,25(OH)2vitaminD3 without any additional stromal cells, and that formation was further facilitated by macrophage-colony stimulating factor. Furthermore, we show that osteoclast-like cells are formed in co-culture of peripheral blood mononuclear cells and rheumatoid synovial fibroblasts obtained by continued sub-cultures. The multinucleated cells showed all the phenotypical and functional characteristics of osteoclasts including the expression of tartrate resistant acid phosphatase, vitronectin receptors, receptors for human calcitonin and the ability to resorb bone. These results indicate that synovial macrophages are capable of differentiating into osteoclasts in the presence of rheumatoid synovial fibroblasts which can support differentiation of monocytes/ macrophages, implicating that osteoclasts generated within the synovial membrane are probably involved in bone destruction in rheumatoid arthritis.

Acid Phosphatase↗

PubMed1998

IL-13 as well as IL-4 induces monocytes/macrophages and a monoblastic cell line (UG3) to differentiate into multinucleated giant cells in the presence of M-CSF.

The formation of multinucleated giant cells (MGCs) from monocytes/macrophages is controlled by various cytokines whose crucial roles are not fully understood. In this study, we found that interleukin (IL)-13 as well as IL-4 induced peripheral blood monocytes (PBMs) and monoblastic cell line, UG3, to differentiate into MGCs in the presence of macrophage colony-stimulating factor (M-CSF), while IL-2, IL-7 or IL-10 did not. The presence of M-CSF was essential to this MGC formation, because IL-3 or granulocyte-macrophage colony-stimulating factor (GM-CSF) could not replace M-CSF. IL-4 and IL-13 have been known to inhibit the formation of osteoclast-like cells in the presence of stroma cells or osteoblastic cells. But in our system without stroma cells, IL-4 or IL-13 induced some of characteristics of osteoclasts such as tartrate-resistant acid phosphatase (TRAP) activity, vitronectin receptor (vit-R) expression and resorptive activity for hydroxyapatite, but not the expression of receptors for parathyroid hormone or calcitonin. These results suggest possible involvement of IL-4 and IL-13 in MGCs and osteoclasts development, and UG3 may be useful to further investigate the roles of IL-4 and IL-13 in the formation and physiology of MGCs, and the relationship between these MGCs and osteoclasts.

Acid Phosphatase↗

PubMed2000

Contortrostatin activates ERK2 and tyrosine phosphorylation events via distinct pathways.

We report that cells adhering to contortrostatin show transient increases in activation of Extracellular signal Regulated Kinase 2 (ERK2). The kinetics and degree of activation are similar to cells adhering to fibronectin or vitronectin. We have recently shown that contortrostatin induces tyrosine phosphorylation in tumor cells. Contortrostatin is shown here to stimulate activation of ERK2 in suspended cells, but this activation follows a different dose-response pattern than contortrostatin-induced tyrosine phosphorylation. Since contortrostatin induces tyrosine phosphorylation via alphavbeta3, we explored the effects of an alphavbeta3-blocking antibody, 7E3, on contortrostatin-stimulated ERK2 activation. While 7E3 completely blocks the effect of contortrostatin on tyrosine phosphorylation, this antibody had no effect on activation of ERK2. In cells lacking expression of alphavbeta3, tyrosine phosphorylation was unaffected by contortrostatin treatment, but ERK2 was activated. This is strong evidence that contortrostatin is regulating tyrosine phosphorylation events and ERK2 activation via separate pathways and through different integrin receptors.

Cell Adhesion↗

PubMed2001

Differential phosphorylation of paxillin in response to surface-bound serum proteins during early osteoblast adhesion.

An early signaling event during the adhesion and spreading of cells is integrin-mediated tyrosine phosphorylation of the cytoskeletal adaptor protein paxillin and the non-receptor tyrosine kinase pp125(FAK) at focal contacts. To determine the influence of surface-charge and -adsorbed adhesion proteins on this signaling pathway, paxillin phosphorylation was examined during attachment of MC3T3-E1 osteoblast-like cell onto charged and uncharged polystyrene, and on adsorbed layers of serum proteins, fibronectin (Fn), vitronectin (Vn), a mixture of Fn and Vn, and albumin. Paxillin phosphorylation was induced 2.4-fold (P < 0.05) on charged vs uncharged polystyrene only in the presence of serum proteins. Activation of paxillin via Fn or Vn alone, or in combination, resulted in significantly lower phosphorylation signals compared to whole serum (41 +/- 6.9%, P < 0.05, 45 +/- 5.9%, P < 0.05, and 76 +/- 9.8%, P < 0.075, respectively). Confocal laser microscopy confirmed increased co-localization of phosphotyrosine and paxillin at protruding lamellopodia of spreading osteoblasts on charged vs uncharged serum-pretreated polystyrene. Taken together, these data suggest that subtle differences in surface characteristics mediate effects on adhering cells via adsorbed serum proteins involving the cytoskeletal adaptor protein paxillin.

3T3 Cells↗

PubMed2001

Costimulation by extracellular matrix proteins determines the response to TCR ligation.

Although ligation of the T-cell antigen receptor (TCR) is central to the responsiveness and antigen specificity of T-cells, it is insufficient to elicit a response. To determine whether the need for costimulation reflects inadequate strength of signal transduction through the TCR or an absolute block of signaling in the absence of a coligand, we studied T-cell activation under serum-free conditions eliminating costimulation by various extracellular matrix proteins which otherwise have an omnipresent and frequently overlooked effect. Engagement of the TCR leads to induction of Fas, but not to measurable IL-2 secretion or apoptosis. Those activation parameters are induced by costimulation through integrin alphaVbeta3. Furthermore, T-cell survival or elimination is determined by the type of ligand binding to this coreceptor with vitronectin, fibronectin, and fibrinogen efficiently inducing apoptosis and IL-2 production while osteopontin and entactin mediate IL-2 secretion comparably without causing programmed cell death. Consistent with the cytokine properties of these ligands, differential costimulation depends on their presentation in soluble rather than immobilized form. The determination of elimination versus survival of activated T-cells by coligation of beta3-integrins may have bearing on the fundamental postthymic mechanisms that shape the T-cell repertoire.

Animals↗

PubMed1998

Stimulation of G-CSF gene expression in the macrophage cell line by contact with extracellular matrix proteins and a pre-B leukaemia cell line.

In order to scrutinize the adherence-dependent interactions for induction of granulocyte colony-stimulating factor (G-CSF) in peripheral monocytes/macrophages, a sensitive reporter gene assay was constructed using the mouse macrophage cell line transfected with the mouse G-CSF promoter region in conjunction with the luciferase gene as a reporter. With this system, lipopolysaccharide (LPS) showed a markedly positive response. Among the extracellular matrix (ECM) proteins, both fibronectin (FN) and vitronectin (VN) markedly induced luciferase activity, but others did so but much lesser extent. Among the synthetic peptides having Arg-Gly-Asp (RGD) sequences, only FLEPP with multiple RGD significantly induced luciferase activity. Pretreatment of the cells with anti-integrin alpha 6, alpha M, beta 1 and beta 2 monoclonal antibodies (mAbs) significantly reduced the LPS-induced responses and anti-alpha 1, alpha 2 and beta 3 mAbs to lesser extent, and anti-alpha 5, alpha 6, alpha M, beta 1 and beta 2 mAbs blocked the FN-induced response. In the cell-to-cell interactions, significantly positive increase was observed by direct contacting this cell line with a G-CSF-dependent promyelocytic leukaemia cell line, known to stimulate the induction of G-CSF to the stromal cells. Its effect was mostly blocked by pretreatment with anti-integrin alpha 5, alpha L, beta 1 and beta 2 and anti-ICAM-1 mAbs. These results indicate that there are several pathways via the cell-to-ECM and cell-to-cell interactions triggering the induction of G-CSF in the macrophages.

Animals↗

PubMed1997

Division of labor of Schwann cell integrins during migration on peripheral nerve extracellular matrix ligands.

Myelination of the peripheral nervous system (PNS) requires the migration of Schwann cells during both development and regeneration. We have characterized the expression pattern of Schwann cell integrins and analyzed their role in migration on different ECM substrates known to be present within the PNS. We found that Schwann cells in cell culture express four beta1 integrins, alpha1 beta1, alpha2 beta1, alpha6 beta1, and another unidentified beta1 integrin, as well as two alpha v integrins, alpha v beta3 and alpha v beta8. Using the Varani migration assay, we found that laminin-1, laminin-2 (merosin), and fibronectin increased Schwann cell migration, while vitronectin and collagen did not increase migration compared to an uncoated plastic substrate. Schwann cell migration on laminin-1 and laminin-2 (merosin) was blocked by antibodies against beta1 integrins, but not affected by RGD peptides or antibodies against beta3 integrins. In contrast, migration on fibronectin was unaffected by antibodies against beta1 and beta3 integrins but was blocked by RGD peptides. This in vitro study shows that there is a division of labor of Schwann cell integrins in the regulation of migration on peripheral nerve ECM components; beta1 integrins mediate migration on laminin-1 and laminin-2 (merosin), while alpha v integrins mediate migration on fibronectin. Taken together, these results suggest that multiple interactions between Schwann cell integrins and ECM within the PNS will contribute to Schwann cell migration during myelination of the PNS.

Animals↗

PubMed1993

Promotion of cell adhesion on fibronectin during adenovirus infection of KB cells.

Cytopathic effects of adenovirus-infected human cells consist of rounding and detachment from the substrate at late times postinfection. It is not known, however, whether any changes in cell adhesion are induced by adenoviruses before cytopathic effects become evident. We show here that attachment and spreading of human adenovirus type 2 (Ad2)-infected KB cells on fibronectin (FN) are, unexpectedly, promoted at intermediate times postinfection. The promotion of spreading by Ad2 is not only on fibronectin but also on laminin and vitronectin. In contrast, Ad2 or Ad5 mutants defective in the E1b 19-kDa function did not lead to a promotion in cell attachment but they led to a promotion in cell spreading. Inhibition of spreading of Ad2-infected KB cells on FN by the peptide Gly-Arg-Gly-Asp-Ser-Pro is partial, although it is complete in uninfected KB cells. We found, however, that Ad2 infection does not significantly change the levels of expression of beta 1 integrin mRNA and FN receptor polypeptides. Our results thus suggest that adenovirus infection leads to a promotion in adhesion through influencing integrin molecules without altering the quantity and/or through activation in the cytoskeleton or some other pathway.

Adenoviridae Infections↗

PubMed1993

Modification of integrin-mediated cell attachment to substrata by serine proteinases in the presence and absence of divalent cations.

The sensitivity to serine proteinases of cellular proteins involved in cell-matrix adhesion was investigated using C32 melanoma cells. Cells dissociated from monolayers by the metal chelator ethylenediaminetetraacetic acid were incubated with proteolytic enzymes, and then attachment was quantified by standard cell adhesion assays. The effect of proteinases was found to depend on the presence of Ca2+ in the incubations. Incubation with 100 nM trypsin or chymotrypsin for 1-2 h (37 degrees C) in the absence of Ca2+ reduced cell attachment to vitronectin (Vn), fibrinogen (Fb), laminin, and fibronectin by approximately 80, 80, 40, and 30%, respectively. Viability studies indicated that such treatment with proteinases was not cytotoxic. Inclusion of 0.1 nM CaCl2 in the incubations prevented the loss in attachment to all substrata. In the case of Fb, proteinase treatment in the presence of Ca2+ had an additional effect; it improved cell attachment to this substratum by about 50%. C32 cells have been shown to express the integrin alpha v beta 3 (Vn receptor) which mediates attachment to Vn and Fb in a GRGDS-sensitive manner. Attachment of C32 cells to Vn and Fb prior to proteinase treatment and after proteinase treatment in the presence of Ca2+ was 90% inhibited by the addition of GRGDS peptide to the attachment assays. These results suggest that the adhesion observed both before and after proteinase treatment was mediated by this integrin. Analysis of the Vn receptor from proteinase-treated cells by immunoblotting of cell extracts and by SDS gel electrophoresis of immunoprecipitated receptor revealed no detectable change in either the alpha v or beta 3 subunit that correlated with loss in attachment. Similarly proteinase treatment in the presence of Ca2+ did not produce detectable alterations in the subunits which might correlate with the improved attachment to Fb. Consistent with these results, an enzyme-linked immunoassay to quantify cell surface receptors revealed little difference in the amount of Vn receptor on cells treated with proteinase in the presence or absence of Ca2+. Degradation of the alpha v subunit was demonstrated, however, at proteinase concentrations higher than those required to affect cell attachment. Thus, treatment of cells with serine proteinases can affect integrin-mediated attachment to matrix proteins in a manner moderated by Ca2+, but the alterations in attachment do not appear to be accompanied by detectable proteolytic modification of the integrin.

Amino Acid Sequence↗

PubMed1994

Heat shock-induced shedding of cell surface integrins in A549 human lung tumor cells in culture.

The human lung carcinoma-derived cell line A549 attaches to plastic and vitronectin-coated substrates in a manner dependent upon the specific cell surface integrin alpha v beta 3. Exposure to hyperthermic temperatures (42-45 degrees C) causes these cells to detach from the substrates. In heat-shocked cultures, the alpha v, alpha 5, and beta 3 integrin subunits remain attached to the substrate. Analysis of individual cells by fluorescence-activated cell sorting shows that cell surface levels of alpha v beta 3 decrease by up to 10-fold in response to heat shock, while the abundance of another integrin found on the surface of A549 cells, alpha 3 beta 1, is only minimally affected by this stress. Heat shock-induced decreases in alpha v beta 3 also occur in cells growing in suspension cultures, showing that physical attachment onto an extracellular substrate is not required for the hyperthermia-induced loss of this integrin. The heat shock-induced detachment of the cells and the shedding of alpha v beta 3 from the cell surface can be inhibited by fetal bovine serum and alpha 2 macroglobulin. Reattachment of A549 cells to substrate is reduced by heat shock. These results demonstrate that heat shock can reduce the cell surface abundance of specific integrin subunits, some of which are involved at sites of cellular attachment to extracellular substrates. These findings may be relevant to the heterogeneous patterns of invasion and metastasis of human tumors following fevers or hyperthermia therapy.

Cell Adhesion↗

PubMed1994

Reciprocal interactions between human ovarian surface epithelial cells and adjacent extracellular matrix.

The human ovarian surface epithelium (OSE), or ovarian mesothelium, is functionally complex as seen by its capacity to proliferate, migrate, and contribute to ovulation and ovulatory repair in response to cyclic hormonal and environmental changes. We wished to determine whether this phenotypic versatility is reflected in cell-extracellular matrix interactions in primary and low-passage culture. Comparisons of cultures maintained on different substrata revealed that these cells form cohesive monolayers on plastic, while fibrin clots enhance cell dispersion, and thus may provide a migratory cue. The cells invaded Matrigel as multicellular aggregates, while collagen gels mediated a morphologic epithelial-mesenchymal conversion. On plastic, the cells produced extracellular matrix components characteristic of epithelial basement membrane (laminin and collagen type IV), as well as stroma (collagen types I and III). In addition, ovarian surface epithelial cells secreted serine proteases and matrix metalloproteinases. The levels of chymotrypsin- and elastase-like proteases were dictated by the substratum: low levels were secreted by cells grown on plastic, intermediate levels on collagen gels and fibrin clots, and most protease was produced on Matrigel. The rate of cell proliferation varied with the substrata and was inversely related to protease secretion. Integrin expression was greatest on plastic and least on collagen gels where integrins were downregulated with time. alpha 6/beta 4 was absent from all cells while varying levels of alpha 2, alpha 3, alpha 5, beta 1, and vitronectin receptor were detected depending on the culture substratum employed. In low-passage cultures of human ovarian surface epithelial cells, then, cell shape, growth, protease production, and integrin expression are modulated by the extracellular matrix. The cells, in turn, alter extracellular matrix by synthesis, lysis, and physical remodeling, and express both stromal and epithelial characteristics. The broad repertoire of these functions may be related to their mesodermal origin, and may reflect the expression of a dual, epithelio-mesenchymal phenotype by relatively immature, uncommitted cells. The results demonstrate the great complexity and versatility of these interactions which render OSE cells capable of participating in numerous physiological and pathological processes.

Adult↗