Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0025202 (melanoma)
 69,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have investigated the morphology and migratory behavior of quail neural crest cells on isolated embryonic basal laminae or substrata coated with fibronectin or tenascin. Each of these substrata have been implicated in directing neural crest cell migration in situ. We also observed the altered behavior of cells in response to the addition of tenascin to the culture medium independent of its effect as a migratory substratum. On tenascin-coated substrata, the rate of neural crest cell migration from neural tube explants was significantly greater than on uncoated tissue culture plastic, on fibronectin-coated plastic, or on basal lamina isolated from embryonic chick retinae. Neural crest cells on tenascin were rounded and lacked lamellipodia, in contrast to the flattened cells seen on basal lamina and fibronectin-coated plastic. In contrast, when tenascin was added to the culture medium of neural crest cells migrating on isolated basal lamina, a significant reduction in the rate of cell migration was observed. To study the nature of this effect, we used human melanoma cells, which have a number of characteristics in common with quail neural crest cells though they would be expected to have a distinct family of integrin receptors. A dose-dependent reduction in the rate of translocation was observed when tenascin was added to the culture medium of the human melanoma cell line plated on isolated basal laminae, indicating that the inhibitory effect of tenascin bound to the quail neural crest surface is probably not solely the result of competitive inhibition by tenascin for the integrin receptor. Our results show that tenascin can be used as a migratory substratum by avian neural crest cells and that tenascin as a substratum can stimulate neural crest cell migration, probably by permitting rapid detachment. Tenascin in the medium, on the other hand, inhibits both the migration rates and spreading of motile cells on basal lamina because it binds only the cell surface and not the underlying basal lamina. Cell surface-bound tenascin may decrease cell-substratum interactions and thus weaken the tractional forces generated by migrating cells. This is in contrast to the action of fibronectin, which when added to the medium stimulates cell migration by binding both to neural crest cells and the basal lamina, thus providing a bridge between the motile cells and the substratum.
 ...
PMID:The effect of tenascin and embryonic basal lamina on the behavior and morphology of neural crest cells in vitro. 246 93

Carcinoma cells express a novel integrin involved in cell adhesion to vitronectin, but not to fibrinogen or von Willebrand factor, whereas melanoma and endothelial cells express a vitronectin receptor (alpha v beta 3) that promotes cell attachment to all of these matrix components. The integrin responsible for this adhesive phenotype of carcinoma cells is composed of an alpha subunit that is indistinguishable from the alpha v of the vitronectin receptor and a beta subunit (beta x) that is distinct from any known integrin beta subunit. Accordingly, Northern blot analysis identifies an mRNA for alpha v, but not for beta 3 in carcinoma cells. This receptor appears to mediate cell adhesion to vitronectin as well as fibronectin since an antibody directed to its alpha subunit blocked carcinoma cell adhesion to both of these matrix proteins. These results suggest that homologous integrins with identical alpha subunits and structurally distinct beta subunits can account for the functional recognition of different matrixes by two cell types.
 ...
PMID:A novel vitronectin receptor integrin (alpha v beta x) is responsible for distinct adhesive properties of carcinoma cells. 246 45

The disialogangliosides GD2 and GD3 play a major role in the ability of human melanoma cells to attach to Arg-Gly-Asp-containing substrates such as fibronectin and vitronectin, since pretreatment of these cells with monoclonal antibodies to the oligosaccharide of GD2 and GD3 can inhibit their attachment and spreading on such adhesive proteins. This report demonstrates that human melanoma cells (M21) synthesize and express a glycoprotein receptor that shares antigenic epitopes with the vitronectin receptor on human fibroblasts and is capable of specifically recognizing the Gly-Arg-Gly-Asp-Ser-Pro sequence. Biochemical evidence is presented indicating that the vitronectin receptor on M21 human melanoma cells contains associated calcium and GD2. This ganglioside copurified with the glycoprotein receptor for vitronectin on affinity columns containing either an Arg-Gly-Asp-containing peptide, Concanavalin A, or lentil lectin. This major Arg-Gly-Asp-directed receptor on M21 cells could be metabolically labeled with 45Ca++. Chelation of this ion with EDTA caused the dissociation of GD2 from the receptor and rendered the remaining glycoprotein incapable of binding to an Arg-Gly-Asp containing peptide. Reconstitution experiments demonstrated a requirement for calcium and not magnesium for receptor binding to Arg-Gly-Asp and indicated that addition of ganglioside can enhance this interaction.
 ...
PMID:Human melanoma cell attachment involves an Arg-Gly-Asp-directed adhesion receptor and the disialoganglioside GD2. 247 Jan 10

Membranes from a B16 murine melanoma clone of high experimental metastatic capacity show increased amounts of pertussis toxin (PT) substrate when compared to a low metastatic counterpart. Using specific antibodies, we identified Gi2 as the PT-sensitive G-protein uniquely abundant in highly metastatic cells. ADP ribosylation of a G-protein alpha subunit by PT decreased both the migration of tumor cells through Matrigel (Collaborative Research, Bedford, MA) and the fibronectin-, laminin-, and collagen type IV-mediated motility of a high metastatic clone. Treatment of cells from a low metastatic clone with PT did not alter either the relatively low invasive capacity or lower motility of these cells. While cholera toxin treatment of cells resulted in decreased invasion and motility of both high and low metastatic clones, there were significant qualitative and quantitative differences, when compared to the PT effects, which indicated that the two toxins were acting on different second messenger systems. PT treatment of B16 clones of high or low experimental metastatic capacity does not result in any alteration in cellular cyclic AMP accumulation suggesting that the PT substrate is not linked with the adenylyl cyclase enzyme complex. The data suggest that a PT-sensitive G-protein, possibly Gi2, regulates second messenger pathways that contribute to the metastatic capacity of B16 melanoma cells.
 ...
PMID:G-protein involvement in matrix-mediated motility and invasion of high and low experimental metastatic B16 melanoma clones. 247 50

An expression vector containing a cDNA complementary to 1.3 kb of the 5' coding sequences of the fibronectin gene in the antisense orientation with respect to its promoter was introduced by electroporation into hybrids between melanoma cells and normal fibroblasts in which malignancy was suppressed. Immunofluorescence analysis of clones transfected with the antisense cDNA showed a dramatic decrease in the amount of fibronectin on the cell surface compared to that seen on the surface of the untransfected hybrid cells or of cells transfected with fibronectin cDNA in the sense orientation or with the expression vector alone. Four out of five clones transfected with the antisense cDNA were highly tumorigenic, whereas transfectants containing either the sense fibronectin construct or the expression vector alone remained non-tumorigenic. These results suggest that antisense RNA to fibronectin may be able to abrogate the suppression of malignancy imposed on the hybrid cells by the fibroblast parent.
 ...
PMID:The effect of antisense RNA to fibronectin on the malignancy of hybrids between melanoma cells and normal fibroblasts. 248 81

Hyaline globular inclusions were found in a case of malignant melanoma. The globules were both intracellular and extracellular in the primary neoplasm and in metastases to lymph nodes, liver, and lung. They were studied immunohistochemically and were found to contain fibronectin, a glycoprotein of high molecular weight. Ultrastructurally, the globules were composed of electron-dense, finely fibrillar aggregates. It is suggested that the neoplastic cells produced the fibronectin, which accumulated in globular form. Ten additional cases of malignant melanoma were studied; none of these had hyaline globules or intracellular globular fibronectin. The globules were compared to similar structures described in Spitz's nevi and other neoplasms. Immunohistochemical analysis was most useful in distinguishing the globules found in the malignant melanoma from those found in other conditions.
 ...
PMID:Fibronectin-containing hyaline globules in malignant melanoma. 248 47

Anti-cell adhesive activity was examined by the synthetic polypeptide, containing repetitive Arg-Gly-Asp sequence of cell attachment site from fibronectin, poly (Arg-Gly-Asp). The attachment of tumour cells to fibronectin substrate was specifically inhibited by adding poly (Arg-Gly-Asp) in cell surface receptor-mediated and divalent cation-dependent manners, but not by unrelated peptides. In our previous study, the lung metastatic formation of tumour cells was dramatically reduced by intravenous co-injection of anti-cell adhesive poly (Arg-Gly-Asp) with B16-BL6 melanoma cells. These findings suggest that polypeptide-mediated inhibition of pulmonary metastasis is partly due to interference with tumour cell adhesion to the substrates including fibronectin in target organs or tissues.
 ...
PMID:Inhibition of tumour cell adhesion by anti-metastatic polypeptide containing a repetitive Arg-Gly-Asp sequence. 248 85

Normal cultured human epidermal melanocytes and melanoma cells derived from three different malignant melanomas were examined for synthesis of extracellular matrix components before and after treatment for one day with interferon-gamma, tumor necrosis factor-alpha, or both. Treatment of the cells with either cytokine individually had minimal effects on fibronectin levels. Treatment of the cells with the two agents in combination greatly stimulated fibronectin production as indicated by biosynthetic labeling and immunoprecipitation and by enzyme-linked immunosorbent assay. Synthesis of laminin was decreased slightly by the same treatment whereas thrombospondin production was stimulated slightly. The same treatment reduced melanocyte viability slightly but significantly inhibited proliferation and altered the morphology of the melanocytes. The treated cells became flattened and polygonal in shape while the untreated cells exhibited a bipolar shape with one or more long dendritic processes. These morphologic changes were not seen in cultures treated with interferon-gamma or tumor necrosis factor-alpha individually. The effects of interferon-gamma and tumor necrosis factor-alpha on fibronectin production by epidermal melanocytes are in contrast to the effects of the same treatments on fibronectin production by epidermal keratinocytes where fibronectin production is decreased but are similar to the effects of transforming growth factor-beta on a number of other cell types in which increased synthesis of fibronectin occurs and is associated with decreased growth.
 ...
PMID:Modulation of fibronectin production in normal human melanocytes and malignant melanoma cells by interferon-gamma and tumor necrosis factor-alpha. 249 26

Plasminogen activators (PAs) convert plasminogen to plasmin by the cleavage of the Arg-Val bond. There are two distinct types of PA, tissue type (t-PA) released from the endothelial cells of the blood vessels and urinary type (u-PA) released from urinary tubules. u-PA was found to be released from activated macrophages and virally transformed cells. t-PA was also found to be released from breast cancer cells induced by carcinogens or melanoma cells. In structure, t-PA has a finger domain homologous to fibrin-binding domain of fibronectin and a growth factor domain homologous to the epidermal growth factor. u-PA has no finger domain but has a growth factor domain. It is proposed that PA may be important in tumor growth due to the stimulation of tumor cells through binding of growth factor domain to its receptor of tumor cells. Another hypothesis is that PA may activate procollagenase to collagenase, which digests collagen to facilitate tumor growth. We have measured the concentrations of t-PA and u-PA in plasma, urine and tumor tissues of patients with cancer of the digestive tract and patients with uterine or ovarian tumors. The results indicate that the concentrations of u-PA increased in urine, plasma and cancer tissues of patients with cancer of the digestive tracts whereas no increase was observed in t-PA levels. On the other hand, the concentration of t-PA increased mostly in plasma of patients with uterine and ovarian cancers, but t-PA levels in tissues did not increase in patients with uterine and ovarian cancer.
 ...
PMID:Plasminogen activators: possible roles in cell proliferation. 250 84

We have identified a protein(s) on the surface of hepatocytes that binds to the core protein of the heparan sulfate proteoglycan of basement membranes. These cells attached and spread on substrates prepared from the basement membrane heparan sulfate proteoglycan (HSPG) and its core protein (HSPG-core). Three proteins (Mr = 38,000, 36,000, and 26,000) were found to bind to a HSPG-core affinity column using extracts of iodinated hepatocytes, whereas proteins extracted from isolated membranes contained primarily the larger protein (Mr = 38,000). Similar results were obtained using a solid phase binding technique using labeled HSPG-core. Binding of HSPG-core to the protein (Mr = 38,000) was not altered by the presence of an excess of heparin, heparan sulfate, fibronectin, laminin, or collagen IV but was reduced by unlabeled HSPG-core. Similar studies showed that the binding protein (Mr = 3,0000) was present in extracts from the membranes of Engelbreth-Holm-Swarm tumor cells, Madin-Darby canine kidney cells, COS cells, melanoma cells, and rat kidney epithelial cells but not in fibroblasts. The protein was found in increased amounts in 3T3 cells treated with retinoic acid. These observations suggest that a variety of cells that contact basement membrane contain the proteoglycan-binding protein.
 ...
PMID:Identification of a cell surface-binding protein for the core protein of the basement membrane proteoglycan. 252 26


<< Previous 1 2 3 4 5 6 7 8 9 10