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

A method for the purification of full-length nerve growth factor receptor (NGFRc) using membranes from three different cell lines was developed. We emphasized recovery of NGFRc that retained specific binding activity. Lipids were required to preserve binding activity during solubilization and throughout the purification procedure. Phosphatidylcholine was used for this purpose. Lectin affinity chromatography followed by high-resolution anion-exchange chromatography was used, and a 3000-fold increase in specific binding activity was obtained for NGFRc from human melanoma A875 membranes. Seven percent of the original binding activity was recovered as pure NGFRc. NGFRc binding activity eluted at 0.35 M NaCl in anion-exchange chromatography of solubilized A875, rat pheochromocytoma PC12, and human neuroblastoma MC-IXC membranes. Eight and three percent of the original binding activity were recovered as highly enriched NGFRc from membranes prepared from PC12 and MC-IXC cells, respectively. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of highly enriched, 125I-labeled NGFRc revealed several protein species. After chromatography, identification of proteins as NGFRc was verified both by immunoprecipitation using receptor-specific monoclonal antibodies and by covalent cross-linking to 125I-NGF using N-hydroxysuccinimidyl-4-azidobenzoate. Predominantly, NGFRc was recovered as a mixture of species of 80 and 160-180 kDa. Small amounts of larger species as well as smaller species were observed, consistent with minor amounts of receptor aggregation and proteolysis occurring during purification.
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PMID:Two-step purification of full-length nerve growth factor receptor and maintenance of receptor-specific binding activity. 196 21

Recombinant human tumor necrosis factor-alpha (TNF-alpha) is a macrophage-derived, non-glycosylated (17 kDa) peptide that has a remarkably broad range of biological and immunological effects including antiviral action and cytotoxic and cytostatic effects. TNF-alpha was coupled to murine antibody ZME-018, which recognizes a 240 kDa glycoprotein present on over 80% of melanoma cells. The crosslinking was accomplished using the heterobifunctional crosslinking reagent, N-succimindyl 3-(2-pyridyldithio)proprionate (SPDP). After purification on gel-permeation and affinity columns, the resulting eluate was analyzed by non-reducing SDS-PAGE, which confirmed that the product was a mixture of ZME-018 coupled to one or two TNF-alpha molecules. The ZME-TNF conjugate was titered against murine L-929 cells to demonstrate the presence of active TNF. ELISA of the conjugate against target BRO human melanoma cells or non-target T-24 cells demonstrated specific binding only to target cells. Melanoma BRO cells were killed by the immunoconjugate (IC50 of 10 units/mL), whereas native TNF-alpha had no effect at concentrations greater than 50,000 units/mL. The immunoconjugate and TNF-alpha were inactive against T-24 non-target cells. These studies suggest that the sensitivity of cells to TNF was dramatically augmented by specific antibody mediated delivery to tumor cells.
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PMID:Antibody-mediated delivery of tumor necrosis factor (TNF-alpha): improvement of cytotoxicity and reduction of cellular resistance. 198 45

Testing of a panel of cultured human melanoma cells with radiolabelled anti-HLA-class-I monoclonal antibodies (MAbs) in a binding assay has shown lack of reactivity of FO-I and SK-MEL-33 cells and low reactivity of SK-MEK-19 cells. SDS-PAGE analysis of the components immunoprecipitated from the 3 intrinsically radiolabelled melanoma cell lines by antibodies to the 2 subunits of HLA-class-I antigens has not detected beta 2-mu in the immunoprecipitates from melanoma cells FO-I and SK-MEL-33 and only a low level of HLA-class-I heavy chain in the immunoprecipitate from SK-MEL-19 cells. Northern blotting analysis with probes specific for HLA-class-I heavy chain and for beta 2-mu indicates that the abnormalities in HLA-class-I-antigen expression reflects a defect at the transcriptional level in FO-I cells and at the post-transcriptional level in SK-MEL-19 and in SK-MEL-33 cells. FO-I, SK-MEL-19 and SK-MEL-33 cells represent useful models to analyze the molecular mechanisms underlying the loss of HLA-class-I-antigen expression which is often associated with malignant transformation of melanocytes and to characterize the role of HLA-class-I antigens in the biology of melanoma cells and in their interactions with effector cells.
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PMID:Molecular abnormalities in the expression of HLA class-I antigens by melanoma cells. 206 75

beta-All-trans retinoic acid (RA) treatment of murine S91-C2 melanoma cells decreases in vitro growth and modulates the glycosylation of specific cellular and cell-surface glycoproteins. The effect of RA treatment on [3H]fucose, [3H]galactose, and [3H]glucosamine incorporation was investigated by metabolic labeling followed by analysis of labeled cellular glycoproteins using polyacrylamide gel electrophoresis in the presence of sodium dodecylsulfate (SDS-PAGE) and fluorography. RA treatment dramatically increased the incorporation of the labeled monosaccharides into one glycoprotein of Mr 160,000 (gp160), which has been previously implicated in the growth-inhibitory effect of RA on these cells. Following RA treatment, cell-surface sialic acid residues on gp160 were also more intensely labeled by NaIO4 oxidation and subsequent NaB[3H]4 reduction than were those on gp160 of untreated cells. The activities of fucosyl- and galactosyltransferase increased about 1.5 to 1.9 times after RA treatment. These results suggest that the increased activities of the two glycosyltransferases is responsible for the increased incorporation of fucose and galactose into gp160.
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PMID:Modulation by all-trans retinoic acid of glycoprotein glycosylation in murine melanoma cells: enhancement of fucosyl- and galactosyltransferase activities. 211 Aug 61

The properties of EHS laminin and its proteolytic fragments E8 and P1 to promote spreading of B16 F1 murine melanoma cells were studied in short-term adhesion assays. The cells exhibited similar attachment rates but distinct spread morphologies on laminin, P1, and E8 fragments. The extent of spreading and the shape of the cells were quantitatively defined by two geometrical parameters: the surface and the form factor. These parameters were computed with an automatic image analyzer. Wheat germ agglutinin (WGA), applied to laminin-coated substrates, totally blocked cell spreading, but did not modify attachment percentages. Under similar conditions, WGA partially inhibited cell spreading on the E8 fragment and had no effect on the P1 fragment. In Western blot analysis, P1 fragment, contrary to laminin and E8, did not bind WGA. Laminin galactosylation and cell treatment with alpha-lactalbumin, which should prevent cell galactosyltransferase (GalTase) from binding to N-acetylglucosamine (GlcNAc) residues of the substrate, had no effect on the spreading ability of B16 F1 cells. The role of laminin N-linked carbohydrate chains in the induction of B16 F1 cell spreading was studied further after endoglycosidase F (Endo F) treatment of the substrates. The loss of carbohydrate chains was estimated by the reduction of iodinated lectin binding and by SDS-PAGE. Endo F treatment of laminin (85% of WGA binding inhibition) and E8 (40-50%) had no effect on cell spreading. In contrast, Endo F treatment of P1 fragment (85% of Con A binding inhibition) reduced both cell surface and form factor of B16 F1 cells. These results suggest that: (i) other spreading systems may act in concert with or in place of GalTase/GlcNAc interactions, (ii) the N-linked sugar chains of P1, which are not recognized by WGA, are involved in the spreading process of B16 F1 cells on this fragment, (iii) the epitopes of E8 fragment and E8 domain in laminin which are responsible for spreading are differently masked by WGA, (iv) the binding of WGA to laminin may impair cell spreading by steric hindrance.
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PMID:Spreading of B16 F1 cells on laminin and its proteolytic fragments P1 and E8: involvement of laminin carbohydrate chains. 211 44

The anticancer effects of retinoids have been recognized both in vivo and in vitro; however, little is known about their mechanism of action. Our study evaluated the effects of retinoic acid on the invasiveness of four human melanoma cell lines in vitro and showed a time-dependent inhibition of the ability of these cells to penetrate matrigel-coated filters. The possible mechanisms of action responsible for the anti-invasive effect were further investigated, and the data showed that retinoic acid-treated cells: (a) secreted lower levels of collagenolytic enzymes detected in type IV collagen-containing polyacrylamide gels compared with control cells, which was demonstrated by a decreased ability to degrade [3H]proline-labeled type IV collagen substrate; (b) showed a reduction in PA activity, primarily in the form of tPA, as demonstrated by chromogenic analysis; (c) showed a heterogeneous response with regard to c-myc, c-fos and c-jun mRNA expression, as determined by Northern blot analysis; and (d) demonstrated a decrease in B-actin levels and an increase in vimentin, as demonstrated by Northern blot analysis and SDS-PAGE transblot analysis. Collectively, these data suggest that RA causes an inhibitory effect on tumor cell invasion through a reconstituted basement basement membrane matrix by suppressing type IV collagenolytic activity and PA activity, which is probably triggered through a complex series of oncogene trans-acting factors, ultimately affecting cytoskeletal expression.
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PMID:Retinoic acid inhibits human melanoma tumor cell invasion. 216 Dec

A protein that catalyzes the decoloration of dopachrome has been partially purified from B16 mouse melanoma tumors. The enzyme is preferentially associated to the melanosomes, but it is also found in the microsomal and cytosolic fractions of cellular homogenates. The protein is clearly different from tyrosinase, and should be related to the dopachrome oxidoreductase (Barber et al. (1984) J. Invest. Dermatol. 83, 145-149) and the dopachrome conversion factor (Korner and Pawelek (1980) J. Invest. Dermatol. 75, 192-195) since the reaction product of dopachrome conversion is 5,6-dihydroxyindole-2-carboxylic acid. The protein appears to have an oligomeric structure, with a molecular mass slightly higher than 300 kDa estimated by gel filtration, whereas the molecular mass of the monomer might be approx. 46 kDa estimated by SDS-PAGE electrophoresis. Its Km for dopachrome is around 100 microM. The enzyme is competitively inhibited by indoles and is unaffected by metal chelators. It also has the ability to increase the amount of melanin formed from L-tyrosine by melanoma tyrosinase, and therefore, cannot be considered an 'indole blocking factor' as was suggested for the related dopachrome oxidoreductase. Since the reaction catalyzed by the enzyme is a tautomeric shift on dopachrome, we would propose dopachrome tautomerase (EC 5.3.2.3) as the most precise and informative name.
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PMID:Regulation of mammalian melanogenesis. I: Partial purification and characterization of a dopachrome converting factor: dopachrome tautomerase. 216 85

Human dermal fibroblasts in culture secrete three protein-like neutrophil chemotactic factors, when stimulated either with human rIL-1 alpha or IL-1 beta; not, however, after incubation with LPS. These three fibroblast-derived neutrophil-activating proteins (FINAP) could be purified by subsequently performed reversed phase and size exclusion HPLC. By high resolution SDS-PAGE, all the proteins were shown to migrate with an Mr of 6,700 (alpha-FINAP), 3,600 (beta-FINAP), and 5,300 (gamma-FINAP). All purified cytokine preparations were found to be chemotactic for human neutrophils. In addition, all FINAP induced release of lysosomal enzymes in neutrophils. Deactivation of chemotaxin-elicitable enzyme release showed cross-desensitization of all FINAP with NAP-1/IL-8. Western blot analysis of alpha-FINAP by using mAb against neutrophil-activating protein (NAP)-1/IL-8 reveals immunologic cross-reactivity with NAP-1/IL-8. By amino-terminal amino acid sequence analysis alpha-FINAP could be identified as the 77-residue extended form of NAP-1/IL-8 containing the 79-residue form as a minor contaminant. Whereas beta-FINAP has been found to be a truncation product of alpha-FINAP, gamma-FINAP shows identity with authentic melanoma growth stimulatory activity with respect to retention time upon reversed phase HPLC, high resolution SDS-PAGE, and biologic properties, as well as amino-terminal amino acid sequence. These data show that human dermal fibroblasts may actively participate in inflammatory reactions by secretion of proinflammatory cytokines.
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PMID:IL-1 alpha or tumor necrosis factor-alpha stimulate release of three NAP-1/IL-8-related neutrophil chemotactic proteins in human dermal fibroblasts. 217 8

Purification of monocyte-derived NAP-1/IL-8 by preparative reversed-phase (RP)-HPLC led to the detection of a second peak with polymorphonuclear leukocyte (PMNL)-activating (degranulation, chemotaxis) properties. The monokine responsible for this biological activity, which we tentatively termed NAP-3, could be purified to homogeneity by three different RP-HPLC steps. Tricine-SDS-PAGE analysis gave a single line at Mr 5.3 kD (NAP-1/IL-8 = 5.8 kD). NH2-terminal amino acid sequence analysis read as a major sequence (ASVATELRXCXLQT. .), which shows greater than 40% homology to that of NAP-1/IL-8. The sequence is identical to that found for the 13-kD moiety of melanoma growth stimulating activity (MGSA) and the product of the oncogene gro. Determination of neutrophil chemotactic activity of NAP-3 revealed a typical bell-shaped dose-response curve (ED50 = 2 ng/ml) with no significant neutrophil chemotactic activity at doses greater than 200 ng/ml. Also, in cytochalasin B-pretreated PMNL, NAP-3 elicited release of myeloperoxidase and beta-glucuronidase. Crossdesensitization studies in PMNL enzyme release revealed crossreactivities with the NAP-1/IL-8-R on PMNL. NAP-3 (MGSA/gro) appears to represent the first member of the novel supergene family of beta-thromboglobulin-like host defense cytokines, which expresses both mitogenic as well as proinflammatory properties at the nanogram level.
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PMID:Lipopolysaccharide-stimulated human monocytes secrete, apart from neutrophil-activating peptide 1/interleukin 8, a second neutrophil-activating protein. NH2-terminal amino acid sequence identity with melanoma growth stimulatory activity. 218 61

When HMV-II cells (a human malignant melanoma cell line) infected with a newly isolated influenza C strain (Yamagata/1/88) were examined by simple light microscopy, it was found that a large number of cord-like structures which had lengths up to about 500 microns or greater were emerging from the cell surface. The existence of viral glycoproteins (hemagglutinin-esterase, HE) on the surface of these huge structures was confirmed by hemadsorption experiments with erythrocytes from a variety of species as well as by immunofluorescent staining with anti-HE monoclonal antibody. Furthermore, electron microscopy revealed that numerous filamentous particles in the process of budding, each covered with a layer of surface projections approximately 13 nm in length, aggregated with their long axes parallel to form a cord-like structure visible under a light microscope. An electron-dense layer, which presumably consists of membrane protein (M), was seen in cross-sections of all filamentous virions whereas internal nucleocapsids were rarely seen. SDS-polyacrylamide gel electrophoresis of the purified cords also showed that they contained HE and M polypeptides but not nucleoprotein, confirming that long filamentous particles are mostly devoid of nucleocapsids. The emergence of cords on the cell surface was observed in various cell cultures infected with C/Yamagata/1/88 though their number and length varied markedly depending on cell type. The production of cord-like structures was also evident in HMV-II cells infected with any of several different influenza C strains, which suggests that the cord formation is a common feature of influenza C virus group.
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PMID:Characterization of the cord-like structures emerging from the surface of influenza C virus-infected cells. 221 19


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