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The effect of alendronate on cytokine production, adhesion molecule expression, and transendothelial migration of human peripheral blood mononuclear cells.

Since both osteoclasts and macrophages belong to the mononuclear phagocytic system it is conceivable that bisphosphonates not only affect bone metabolism but also inflammatory responses. The migration of mononuclear cells into perivascular tissue is a central event in inflammatory reactions. We studied the effects of the aminobisphosphonate alendronate on the transendothelial migration of human peripheral blood mononuclear cells in an in vitro model. Alendronate (at a concentration of 100 microM) significantly increased the percentage of peripheral blood mononuclear cells that migrated through endothelial cell monolayers. Similar results were obtained with another aminobisphosphonate, viz, pamidronate. An overnight treatment of the endothelial cell monolayers with alendronate did not alter the rate of peripheral blood mononuclear cells that subsequently migrated. The overnight cultivation of the peripheral blood mononuclear cells in the presence of alendronate resulted in an increased surface expression of CD54 (intercellular adhesion molecule-1, ICAM-1) in both CD14(+) and CD3(+) cells; in CD14(+) cells also the expression of CD49d (alpha4 subunit of late activation antigen-4, VLA-4) increased after alendronate treatment. Alendronate treatment of peripheral blood mononuclear cells also resulted in an increased production of interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), and interferon-gamma (IFN-gamma). We conclude that alendronate has a distinct effect on the transendothelial migration of human peripheral blood mononuclear cells in vitro. Alendronate may either directly or indirectly, e.g., by augmenting the production of proinflammatory cytokines, influence the expression of certain adhesion molecules and thereby facilitate transendothelial migration. These effects could be related to the transient leukopenia reported following intravenous administration of relatively high doses of aminobisphosphonates for the treatment of hypercalcemia of malignancy.

Alendronate↗

Involvement of tumor necrosis factor alpha and very late activation antigen 4/vascular cell adhesion molecule 1 interaction in surgical-stress-enhanced experimental metastasis.

We examined the influence of surgical stress on hematogenous metastasis of malignant tumor cells. The study was performed by focusing on the involvement of inflammatory cytokines in the serum, raised acutely after surgery, and endothelial adhesion molecules in the metastatic process. Surgical stress, given to C57BL/6 mice before B16-BL6 melanoma inoculation, significantly enhanced the pulmonary metastasis. This enhancement was seen when the surgery lasted for more than 2 h. After the 2-h surgery, the enhancement of pulmonary metastasis was seen most remarkably when B16-BL6 was inoculated 24 h after surgery. The serum level of tumor necrosis factor alpha (TNF alpha) in the mice that underwent the 2-h surgery peaked 12 h after the surgery. In contrast, serum interferon gamma was not detectable. Administration of an anti-TNF alpha mAb before the surgery inhibited the enhanced metastasis by inhibiting the increased expression of vascular cell adhesion molecule 1 (VCAM-1) on lung vascular endothelium after the surgery. Pretreatment of B16-BL6 cells with an anti-very late activation antigen 4 (anti-VLA-4) mAb completely inhibited the enhanced metastasis after surgery. Administration of an anti-VCAM-1 mAb before surgery also inhibited the enhancement. These results indicate that serum TNF alpha, raised by surgical stress, is critically involved in the enhanced pulmonary metastasis of mouse melanoma by inducing VCAM-1 expression on lung vascular endothelium.

Animals↗

E-selectin and very late activation antigen-4 mediate adhesion of hematopoietic progenitor cells to bone marrow endothelium.

Adhesion of CD34+ hematopoietic progenitor cells (HPCs) to sinusoidal endothelium probably plays a key role in homing of transplanted CD34+ HPCs to the bone marrow (BM). We have investigated the role of various adhesion molecules in the interaction of purified CD34+ HPCs derived from BM or peripheral blood (PB) and a human BM-derived endothelial cell line. Adhesion of CD34+ HPCs to endothelial cells was measured with the use of a double-color flow microfluorimetric adhesion assay. In this assay, adhesion is measured under stirring conditions, simulating blood flow in sinusoidal marrow vessels. Adhesion of PB CD34+ cells to human BM endothelial cells (HBMECs) was observed only after interleukin (IL)-1beta prestimulation of the endothelial cells. This adhesion was strongly increased after addition of phorbol-myristate acetate (PMA). Adhesion of PB CD34+ cells to IL-1beta-prestimulated HBMECs was inhibited by blocking monoclonal antibodies (mAbs) against E-selectin and by neuraminidase treatment of the PB CD34+ cells. mAbs against very late activation antigen (VLA)-4 inhibited adhesion only when the E-selectin-mediated interaction was prevented. No clear inhibiting effect was found with blocking mAbs against beta2-integrins. Stimulation with the beta1-integrin-activating mAb, 8A2, induced adhesion of CD34+ cells to endothelial cells. In conclusion, stimulation of both endothelial cells and CD34+ HPCs is necessary for adhesion of CD34+ HPCs to endothelial cells. We furthermore demonstrated that E-selectin and VLA-4 mediated this adhesion.

Antigens, CD34↗

[Rheumatoid arthritis: new developments in the pathogenesis with special reference to synovial fibroblasts].

Rheumatoid arthritis (RA) is a chronic inflammatory disease, which is mainly characterized by synovial hyperplasia, pathological immune phenomena and progressive destruction of the affected joints. Various cell types are involved in the pathogenesis of RA including T cells, antigen presenting cells, and endothelial cells. Recent experimental evidence suggests that the CD40/CD154 system might play an important role in the development of RA. Our experimental approach focuses on RA synovial fibroblasts (RA-SF) that are able to destroy articular cartilage independent of inflammation. To elucidate the specific role of those cells in RA pathophysiology the following questions are currently addressed: 1. Which mechanisms do activate the RA-SF? 2. How do the activated RA-SF attach to the cartilage? 3. How do RA-SF destroy cartilage and bone? Which mechanisms do activate the RA-SF? The process of activation is poorly understood. It is unclear, how far the synovial hyperplasia of RA resembles tumor diseases. Along this line some contradictory results exist concerning the role of the tumor suppressor protein p53. Some investigations could show the expression of p53 in the synovial lining including p53 mutations in RA synovium and in RASF, while other research groups could not confirm these data. Our group has demonstrated that the tumor suppressor PTEN was less expressed in the synovial lining of RA than in normal synovium, but no PTEN mutations could be found in the RA-SF. In addition, the in vivo and in vitro expression of the anti-apoptotic molecule sentrin suggests a functional resistance of RA-SF to undergo apoptosis. Although it is still unclear, whether certain viruses or viral elements are involved in the pathogenesis of RA (cause, consequence or coincidence?), certain viruses could play a role in the pathogenesis of RA. The endogenous retroviral element L1 was found to be expressed in the synovial lining, at sites of invasion as well as in RA-SF grown in vitro. Moreover, the data indicate that after the initial activation of L1 downstream molecules such as the SAP kinase 4, the met-protoonocogene and the galectin-3 binding protein are upregulated. How do the activated RA-SF attach to the cartilage? It has been suggested that integrins mediate the attachment of RA-SF to fibronectin rich sites of cartilage. Intriguingly, other adhesion molecules such as the vascular cellular adhesion molecule-1 (VCAM) and CS-1, a splice variant of fibronectin, are synthesized by RA-SF. By binding to these adhesion molecules, lymphocytes that express the integrin VLA-4 could be stimulated and thereby maintain the inflammatory process. Osteopontin is an extracellular matrix protein, which is associated with matrix adhesion and metastasis in tumors. In RA synovium, osteopontin was detectable in the synovial lining and at sites of invasion. How do RA-SF destroy cartilage and bone? The destruction of cartilage and bone in RA is mediated by matrix metalloproteinases (MMPs) and cathepsins. MMPs exist as secreted and as membrane bound forms. In vitro models are being developed to simulate the invasive process of RA-SF. In an in vitro model developed in our laboratory, the treatment of RA-SF with anti-CD44 or anti-interleukin-1 (IL-1) minimized matrix degradation of RA-SF. On the other hand, co-culture of RA-SF and U937 cells as well as application of interleukin-1 beta (IL-1 beta) or tumor necrosis factor alpha (TNF alpha) increased the invasiveness of RA-SF. Gene transfer of bovine pancreas trypsin inhibitor (BPMI) or interleukin-10 (IL-10) reduced the invasion of RA-SF, while transduction of interleukin-1 receptor antagonist (IL-1Ra) was chondroprotective. Double gene transfer of IL-10 and IL-1Ra resulted in both inhibition of invasion and chondroprotection.

Arthritis, Rheumatoid↗

Blockade of signaling via the very late antigen (VLA-4) and its counterligand vascular cell adhesion molecule-1 (VCAM-1) causes increased T cell apoptosis in experimental autoimmune neuritis.

We characterized the early effects of anti-very late antigen (VLA-4) and its counterligand vascular cell adhesion molecule-1 (VCAM-1) antibody therapy on T cell infiltration and apoptosis in adoptive transfer experimental autoimmune neuritis of female Lewis rats. At the peak of disease, animals were treated with anti-VCAM-1 monoclonal antibody (mAb), anti-VLA-4 mAb, or the respective isotype mAb controls 18, 12, or 6 h before perfusion. Anti-VCAM-1 led to a rapid, significant increase of apoptotic T cells in the sciatic nerve with a maximum after 6 h, preceding the significant decrease of T cell infiltration seen after 18 h. This was accompanied by a significant reduction in mRNA levels for IFN-gamma and inducible nitric oxide synthase. The results for anti-VLA-4 treatment showed a similar trend. The early increase of T cell apoptosis following disruption of VLA-4/VCAM-1 interaction may reflect a novel signaling component of proapoptotic pathways.

Animals↗

Post-mortem markers of sepsis: an immunohistochemical study using VLA-4 (CD49d/CD29) and ICAM-1 (CD54) for the detection of sepsis-induced lung injury.

The up-regulation of different adhesion molecules such as VLA-4 (CD49d/CD29) and ICAM-1 (CD54) on the pulmonary endothelium and leukocytes, is a key event in sepsis-induced lung injury leading to inflammatory tissue alterations. The value of VLA-4 and ICAM-1 as micromorphological post-mortem markers for the detection of sepsis-induced lung injury, was evaluated in a semiquantitative immunohistochemical study. VLA-4 was strongly expressed on intravascular, interstitial and intra-alveolar leukocytes in sepsis-associated fatalities, whereas in non-septic fatalities an irregular weak immunoreactivity was observed on interstitial leukocytes and no positive immunohistochemical expression was detected on intravascular or intra-alveolar leukocytes. ICAM-1 was strongly expressed on endothelial cells of the pulmonary microvasculature and on pulmonary macrophages and lymphocytes in sepsis-associated fatalities. In contrast, an infrequent weak immunohistochemical reaction for ICAM-1 was found on pulmonary endothelium and on perivascular leukocytes in non-septic fatalities. Based on the results of the present preliminary study, VLA-4 and ICAM-1 can be considered as useful immunohistochemical post-mortem markers of sepsis.

Adult↗

Immunological effects of in vivo interferon-beta1b treatment in ten patients with multiple sclerosis: a 1-year follow-up.

Ten patients with multiple sclerosis and treated with interferon-beta1b (IFN-beta1b) were followed-up for 1 year with quantitation of serum VCAM-1 and ICAM-1 levels, mean fluorescence intensity of HLA-DR, VLA-4, CD11a, and CD18 on peripheral blood monocytes and lymphocytes, and adhesion of peripheral blood monocytes and CD45+ cells on endothelial cell monolayers. Adhesion molecule expression and adhesion of peripheral blood monocytes to endothelium were also monitored in healthy controls. No differences in adhesion were detected between MS patients before treatment and healthy controls, while after 1 year a marked decrease in the number of monocytes and mononuclear cells adhering to human umbilical vein endothelial cell monolayers was observed in patients treated with IFN-beta1b. After 1 year of treatment a significant increase in HLA-DR on peripheral blood monocytes was also detected. Our findings regarding lowered adhesion add information to available evidence of the mechanisms of action of IFN-beta1b in MS.

Adjuvants, Immunologic↗

Expression of adhesion molecules in allergic lung diseases.

Endothelial adherence and migration of leukocytes into tissue is mediated by different sets of adhesion molecules. The expression of these sets might not only preselect the types of leukocytes that enter the inflammatory sites, but also activate these leukocytes, induce adherence to epithelial cells, and cause the release of cytokines. Atopic asthma, extrinsic allergic alveolitis, and sarcoidosis as examples of immunologic lung diseases were investigated for the expression of adhesion molecules. Bronchial biopsies in chronic obstructive lung disease (COPD) and resected lung tissue of juvenile emphysema were chosen for controls. Immunohistochemistry was done on sections from bronchial and transbronchial biopsies and on smears from bronchoalveolar lavage cells. In all three types of immune disorders, lymphocytes expressed the integrins alpha4/beta1 (VLA4) and ICAM3, whereas lymphocytes in COPD bronchitis and in emphysema controls were unreactive. Eosinophils in atopic asthma bronchitis in contrast to COPD bronchitis also expressed both VLA4 and ICAM3. The expression of VCAM1 on endothelial cells was only seen in atopic asthma and was related to disease activity. The expression of other adhesion molecules was nonspecific. Expression of VCAM1 on endothelial cells and its ligand VLA4 on lymphocytes and eosinophils seems to be a specific event in atopic asthma. Expression of VLA4 and ICAM3 on lymphocytes, however, might be a specific event in all three immune reactions.

Alveolitis, Extrinsic Allergic↗

Adhesion molecules in intestinal Schistosoma mansoni infection.

Adhesion molecules constitute essential elements in inflammation, mediating various cellular interactions. We investigated the expression of adhesion molecules mediating cell-cell [intercellular adhesion molecule-1 (ICAM-1) and lymphocyte function-associated antigen-1 (LFA-1)] and cell-matrix interactions [very late antigen-4 (VLA-4), VLA-6, and syndecan-1] in intestinal granulomas of mice infected with the parasite Schistosoma mansoni. Up-regulation of ICAM-1, LFA-1, and VLA-4 was seen in ileal and colonic granulomas, at both the acute (8 weeks postinfection) and the chronic stage (13-16 weeks postinfection). Up-regulation of VLA-6 was absent in all intestinal granulomas. Syndecan-1 immunoreactive (antigen-driven) B-lymphocytes were seen in the proximity of egg-antigen-laden macrophages in the inner part of ileal and colonic granulomas, although B-cells are considered to be absent in ileal granulomas. Estimation of intestinal granuloma volumes demonstrated the lack of down-modulation observed in ileal granulomas. From our results we infer that adhesion molecules constitute important elements in schistosomal intestinal granuloma formation. Organ-related differences between hepatic and intestinal granulomas exist (e.g., granuloma volume), but these differences are not morphologically reflected in a differential expression of the adhesion molecules ICAM-1, LFA-1, and VLA-4. Syndecan-1 immunoreactive B-lymphocytes also appear to be involved in ileal granuloma formation.

Animals↗

Cellular and molecular basis of preferential metastasis of breast cancer to bone.

Bone is one of the most preferential target sites for cancer metastasis. Breast cancer has a predilection for spreading to bone, and bone metastasis is one of the major causes of increased morbidity and eventual mortality in breast cancer patients. None of the currently available therapies is effective for curing bone metastases in these patients. Elucidation of the cellular and molecular mechanism by which breast cancer selectively spreads to bone is essential for the development of mechanism-based effective and specific therapeutic interventions for this deleterious complication in breast cancer. Here, two questions are addressed to study the mechanism of breast cancer metastasis to bone: (1) What makes bone a preferential target site of metastasis? (2) What makes breast cancer able to colonize bone? (3) An animal model in which intracardiac inoculation of breast cancer cells selectively causes osteolytic bone metastases was developed. Experimental results obtained using this unique in-vivo model of bone metastasis are described and discussed.

Animals↗

Role of the VLA-4 integrin in leucocyte recruitment and bronchial hyperresponsiveness in the guinea-pig.

Guinea-pigs sensitized to ovalbumin develop airway eosinophilia and bronchial hyperresponsiveness to acetylcholine 24 h following ovalbumin challenge. We have used an antibody to the very late antigen-4 (VLA-4) integrin (HP 1/2) to investigate the role of this integrin in the recruitment of leucocytes to the airways and to study the link between eosinophilia and the development of bronchial hyperresponsiveness. In this model, HP 1/2 reduced the number of eosinophils recovered from bronchoalveolar lavage fluid, as well as reducing the activity of the enzyme eosinophil peroxidase in both bronchoalveolar lavage fluid and whole lung extracts. However, HP 1/2 did not reduce bronchial hyperresponsiveness. The results suggest that after antigen challenge, the VLA-4 integrin is involved in the recruitment of leucocytes to the airways at the level of the vascular endothelium, but increased numbers of eosinophils in lavage fluid or in the lung tissue are not an essential correlate of bronchial hyperresponsiveness in this model.

Acetylcholine↗

Alpha 4 beta 7 integrin mediates lymphocyte binding to the mucosal vascular addressin MAdCAM-1.

The mucosal vascular addressin, MAdCAM-1, is an immunoglobulin superfamily adhesion molecule for lymphocytes that is expressed by mucosal venules and helps direct lymphocyte traffic into Peyer's patches (PP) and the intestinal lamina propria. We demonstrate that the lymphocyte integrin alpha 4 beta 7, also implicated in homing to PP, is a receptor for MAdCAM-1. Certain antibodies to alpha 4 and beta 7 integrin chains but not to the beta 2 integrin LFA-1 inhibit lymphocyte binding to purified MAdCAM-1 and to MAdCAM-1 transfectants. Lymph node lymphocytes, alpha 4 beta 7+ TK1 lymphoma cells, and a beta 7-transfected variant of an alpha 4+ B cell line, 38C13, bind constitutively to MAdCAM-1. Binding is enhanced by Mn(++)-induced integrin activation. The related integrin alpha 4 beta 1 supports efficient binding to VCAM-1 but not to MAdCAM-1, even after integrin activation, indicating that MAdCAM-1 is a preferential ligand for alpha 4 beta 7. Alpha 4 beta 7 can also bind VCAM-1, but this requires greater integrin activation than binding to MAdCAM-1. The findings imply a selective role for the interaction of alpha 4 beta 7 and MAdCAM-1 lymphocyte in homing to mucosal sites.

Animals↗

Expression of the integrin alpha 4 beta 1 on melanoma cells can inhibit the invasive stage of metastasis formation.

Among a series of adhesion molecules, expression of integrin alpha 4 beta 1 showed a unique inverse correlation with the invasive potential of B16 melanoma cell lines. When an alpha 4 cDNA was introduced into an alpha 4-beta 1+ highly invasive melanoma line, alpha 4 beta 1 heterodimers were expressed on the surface. Matrigel invasion by the alpha 4+ beta 1+ cells was reduced. Pulmonary metastasis was also suppressed when the transfectants were placed subcutaneously, but not when injected intravenously. Expression of alpha 4 beta 1 promoted homotypic intercellular adhesion. The homotypic adhesion was abrogated, and the alpha 4+ beta 1+ (less invasive cell lines) increased matrigel invasion following the anti-alpha 4 MAb treatment. These results suggest that integrin alpha 4 beta 1 could play a role in controlling melanoma cell metastasis at the invasive stage.

Animals↗

Very late antigen (VLA) expression by normal and neoplastic human plasma cells; including an assessment of antibodies submitted to the Vth International Workshop on Leucocyte Differentiation Antigens using human myeloma cell lines.

The biology of normal plasma cells and the pathophysiology of human multiple myeloma remain poorly understood. Functional assays are scarce and at present cell phenotyping is providing the most information about how human plasma cells may behave. Three different types of human plasma cells: normal, fresh neoplastic myeloma cells and plasma cell lines, have been studied for their reactivity with antibodies to the beta-1 integrins (Very Late Antigens; VLAs), including a panel obtained from the Vth International Workshop on Leucocyte Differentiation Antigens. Most plasma cell targets express VLA-4 (CD49d positive) and the common beta chain recognized by CD29. CD49e (VLA-5) was occasionally positive. Other VLAs were not usually expressed. These data suggest the wide use by plasma cells of VLA-4, possibly as a ligand with fibronectin and high endothelial venules (HEV). Of other adhesion structures expressed by plasma cells, only CD44 is seen as frequently, and this is also a HEV ligand.

Antibodies↗

Characteristics of the T lymphocytes involved in experimental allergic encephalomyelitis.

Both heterogeneity and restricted heterogeneity of the encephalitogenic myelin basic protein (MBP) peptide-specific T cell receptors (TCRs) were demonstrated in inbred animals depending on the strain-specific genetic characteristics, the stage of the disease, the compartment of the lymphocytes obtained and the methodology used. Nevertheless, the similar features of some MBP-specific TCRs demonstrated across species suggest that conservation of these autoantigen-specific molecules undoubtedly exists, even though the degree of this conservation is controversial. However, the unequivocal heterogeneity of the immune response directed at one of the most important myelin constituents, proteolipid lipoprotein (PLP), which occurs either as a primary or a secondary event during experimental allergic encephalomyelitis (EAE), indicates the complexity of the in vivo situation. Intramolecular and intermolecular spreading of antigen specificity during the course of the disease indicates that a TCR directed therapy may not be the choice of intervention in established disease even in individual strains of laboratory animals with restricted heterogeneity of the primary MBP-specific response. Studying the sequence of events, the recruited regulatory cells and cytokines, and the stromal factors controlling persistence or death of activated, memory cells in the tissue lesion, may reveal new therapeutic modalities with more universal applicabilities.

Animals↗

A new phenotypic classification of bone marrow plasmacytosis.

Here, we propose a new phenotypic classification of bone marrow plasmacytosis. By 2-color phenotypic analysis with FITC anti-CD38 and PE anti-CD19, -CD56, -VLA-5 or MPC-1 antibody, plasma cells are easily identified on the histogram, even though no more than 1% of plasma cells are found in the bone marrow. Hence, plasma cells are phenotypically classified into polyclonal (reactive) (CD19+CD56-) or monoclonal (neoplastic) plasma cells (mostly CD19-CD56+), and furthermore immature (VLA-5-MPC-1-), intermediate (VLA-5-MPC-1+) and mature plasma cells (VLA-5+MPC-1+). According to these findings, plasmacytosis in the bone marrow can be classified into polyclonal marrow plasmacytosis (POMP) and monoclonal marrow plasmacytosis (MOMP) states. The MOMP state is further subclassified into MOMP-1 and MOMP-2, MOMP-3 and MOMP-4; MOMP-1 is defined by co-existence of monoclonal plasma cells and polyclonal plasma cells, and MOMP-2 to MOMP-4 are dependent on increased proportions of VLA-5-MPC-1- immature myeloma (plasma) cells. We found that the cases of benign monoclonal gammopathy (BMG) according to the conventional classification were in the MOMP-1 state, and myelomas could be classified into the MOMP-2 to MOMP-4 state. Subclassification of the MOMP state may be useful in determining the prognosis of myelomas, where an increase in immature myeloma cells is reported to correlate well with their aggravation during the clinical courses. Therefore, this new phenotypic classification of bone marrow plasmacytosis (POMP and MOMP-1 to MOMP-4) will contribute to differential diagnosis and understanding of therapeutic responses and prognosis in myelomas.

Antigens, CD19↗

Analysis of lymphocyte costimulation in vivo using transgenic and 'knockout' mice.

The use of transgenic technologies in the functional evaluation of the contributions of costimulatory pathways to T-cell activation in vivo has recently undergone a rapid expansion. During the past two years, mice deficient in costimulatory molecules and their receptors have been generated. These mice have revealed novel and critical in vivo functions of costimulatory pathways and have provided valuable models in which to test therapeutic strategies involving costimulatory pathway blockade. Transgenic mice constitutively expressing costimulatory molecules have provided insights into their role in peripheral tolerance.

Abatacept↗

The relative roles of vitronectin receptor, E-selectin and alpha 4 beta 1 in cancer cell adhesion to interleukin-1-treated endothelial cells.

Adhesion of cancer cells to endothelium is thought to be a prerequisite to extravasation during the haematogenous phase of metastasis, and is enhanced after perturbation of the endothelium by interleukin-1 (IL-1). The inducible endothelial adhesion molecules, E-selectin, VCAM-1/alpha 4 beta 1 and vitronectin receptor have been reported to mediate attachment of cancer cells to IL-1-treated endothelial cells. We have examined the relative contribution of these molecules by quantifying the adhesion of a panel of 22 human, 125I-labelled cancer cells and the rat W256 tumour to untreated and IL-1-treated endothelial monolayers in the presence of relevant neutralising antibodies. Antibodies against E-selectin inhibited the adhesion of HL-60 leukaemia cells and two colon carcinomas. Anti-alpha 4 beta 1 antibodies blocked adhesion of four melanomas, five sarcomas and one lung carcinoma. Anti-vitronectin receptor antibodies inhibited adhesion of 14 of the 22 human cell lines to IL-1-treated endothelial cells. Adhesion of seven cell lines was inhibited by more than a single antibody. In contrast, adhesion of one of the cancer cell lines was unaffected by any of the antibodies, suggesting involvement of other IL-1-inducible endothelial adhesion molecules. Moreover, none of the antibodies altered the attachment of cancer cells to unstimulated endothelial monolayers. We conclude that the mechanisms of cancer cell adhesion to the endothelium are influenced by endothelial activation and by the adhesive repertoire of the cancer cell.

Animals↗