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Query: UMLS:C0025202 (melanoma)
 69,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Suspension cultures of pluripotent teratocarcinoma cells were induced with sodium butyrate to produce plasminogen activator (PA), generally regarded as a marker enzyme of differentiation of the teratocarcinoma. The induction of plasminogen activator was very efficient, resulting in production of sufficient enzyme to allow its purification. The activator was inactivated by rabbit anti-human melanoma plasminogen activator antiserum, indicating that it was a tissue-type activator (t-PA). The enzyme was purified by column chromatograph on phosphocellulose, zinc-chelate agarose, Con-A Sepharose and Sephadex G-150. The preparation at the final step of purification gave a single peak of enzyme activity at pH 7.3 +/- 0.1 on isoelectric focusing, and showed a molecular weight of approximately 77,000 on SDS PAGE.
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PMID:Production, purification and characterization of the plasminogen activator in teratocarcinoma stem cells induced with sodium butyrate. 644 74

Two human melanoma cell lines, largely different from one another in their intrinsic thermosensitivity, were exposed to supranormal temperatures and labeled with 35S-methionine. The protein patterns resolved by SDS-polyacrylamide gel electrophoresis showed in both cell lines an increased synthesis of a unique set of heat shock proteins (HSP) of 72 Kdalton (KD). Already evident after 15 min at 42 degrees C, the relative rate of synthesis of these HSP increased progressively for up to 3 h of continuous heat treatment. The cells exposed for 1 h at 42 degrees C and then returned to 37 degrees C maintained a high relative rate of HSP synthesis for more than 6 h. The rate of decay of the neosynthesized HSP did not differ from that of the overall cell proteins. Since in both cell lines all the parameters concerning HSP induction were identical, no correlation can be established between their intrinsic sensitivity towards the conditioning treatment and the capacity to respond to heat treatment with an increased synthesis of these proteins.
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PMID:Modulation of heat shock protein synthesis in two human melanoma cell lines. 650 23

A melanoma-associated glycoprotein with an apparent molecular weight of 87,000 daltons (gp87) defined by the monoclonal antibody 140.240 has been purified from the spent medium and from cell homogenates of cultured human melanoma cells through a three-step purification procedure. The procedure involves a DEAE-Sephadex A-25 ion-exchange column, SephacrylS-200 gel filtration and antibody-Sepharose-4B-affinity chromatography. By this approach we achieved a 1205-fold increase in specific activity with a 42% antigen recovery from spent medium concentrate, and a 3366-fold increase in specific activity with a 29% antigen recovery from the cell homogenate. The antigen was purified from these two sources of starting material with a high degree of purity as visualized in a single protein band in SDS-polyacrylamide gel electrophoresis. Thus these procedures described offer an efficient approach to the purification of gp87 molecules for further biochemical studies.
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PMID:Purification of melanoma-associated oncofetal antigen gp87 from spent medium and cell homogenate of cultured human melanoma cells. 654 Nov 37

Immune complexes (IC) were isolated from plasma of melanoma patients by absorption to staphylococcal protein A and subsequent elution with MgCl2. The isolated ICs were purified by precipitation with polyethylene glycol and sucrose density gradient ultracentrifugation after radioiodination with 125I. The purified ICs were dissociated and radiolabeled antigen/antibody components were separated by ultracentrifugation at low pH (2.6). Under these conditions, about 72% radioactivity of the purified IC remained in the light-density region as a wide band. After neutralization, 26%-60% radioactivity in the region of 5S sedimentation bound to immobilized autologous immunoglobulins, as opposed to a maximum of 23% to immobilized immunoglobulins from human normal serum. Significant levels (73%-77%) of radioactivity in 7S region bound to rabbit anti-human IgG immunobeads. Immunoprecipitation of the antigen fraction by allogeneic anti-melanoma and rabbit anti-melanoma antibodies followed by SDS-polyacrylamide gel electrophoresis revealed the presence of a fetal antigen (FA) and a melanoma tumor-associated antigen (TAA). In addition, the presence of auto-antigen(s) was indicated by using autologous antibody in immunoprecipitation. Immunoglobulins (IgG) isolated from purified IC bound to cultured melanoma, sarcoma, and normal fibroblasts, although the binding to sarcoma and normal fibroblasts could be inhibited by preincubation of isolated IgG with soluble FA but not with soluble melanoma TAA. Thus, results of this investigation provide evidence that circulating IC in melanoma patients are composed of at least IgG and different antigens, and some of these antigens are produced by their tumor.
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PMID:Nature of antigens and antibodies in immune complexes isolated by staphylococcal protein A from plasma of melanoma patients. 655 50

The HLA-DR antigen expressed on the surface of the human melanoma cell line SK-MEL-37 was characterized and compared with the HLA-DR antigen from the MU B lymphoblastoid cell line originating from the same individual. The HLA-DR heavy chain from SK-MEL-37 cells had an apparent mobility on SDS-PAGE slightly slower than that isolated from MU cells. In contrast, the HLA-DR light chains and the HLA-A,-B heavy chains from the two cell lines had identical mobilities. Double-labeled tryptic peptide mapping and limited N-terminal sequencing showed that the SK-MEL-37 HLA-DR antigen, like all previously examined B lymphoblastoid cell HLA-DR antigens, was homologous to the murine I-E/C subregion antigens and that the mobility difference of the SK-MEL-37 HLA-DR heavy chain was not attributable to differences in the primary structure of the polypeptide. Treatment of the cells with tunicamycin abolished the m.w. difference, suggesting that it was due to a change in glycosylation in SK-MEL-37. This was confirmed by analysis of the glycopeptides from pronase-digested HLA-DR light and heavy chains and HLA-A,B heavy chains purified from the two cell types. The results suggest 1) there is a difference in asparagine-linked oligosaccharide processing in the two cell types, with more of the larger complex glycans synthesized in the melanoma cells than in the B lymphoblastoid cells, 2) the effect is more pronounced with HLA-DR heavy chains than with HLA-DR light chains or HLA-A,B heavy chains, and 3) the oligosaccharide size difference is not solely due to sialic acid content.
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PMID:HLA-DR antigens of autologous melanoma and B lymphoblastoid cell lines: differences in glycosylation but not protein structure. 660 84

Normal human sera were analyzed for the presence and molecular form of two human melanoma-associated antigens (MAAs), the 250 "melanoma-specific" glycoprotein and the 100 K "common tumor antigen". The 250 K MAA was not synthesized by any cultures other than human melanoma and was not detectable in normal human serum. In contrast, the 100 K MAA, which is present in spent medium of cultured human melanoma, carcinoma and fetal melanocytes but not of adult normal cells, was found in normal human serum in nanogram quantities. This serum form of the 100 K MAA was also found in pooled sera of higher apes but not of lower species. The cell-derived form of the 100 K MAA, present in spent culture medium, had a similar phylogenetic distribution. The molecule was produced by cultured brain glia from gorilla, but not by melanoma cells from miniature swine or dog. The 100 K MAA from gorilla glia had a mol. wt identical to the molecule produced by human melanoma cells. Molecular characterization of this MAA in normal human serum showed that it was heterogeneous in size and was present in fractions greater than 100 kd after analytical HPLC gel sieving under non-denaturing conditions. In contrast, MAA from spent culture medium of melanoma cells was 100 kd or less in chemically defined medium (CDM) with no protein supplement, but had a higher mol. wt in CDM with BSA or fetal calf serum supplement, similar to the serum form of the molecule. An association of the 100 K MAA with albumin was demonstrated by analytical HPLC gel sieving and SDS-PAGE analysis of monoclonal antibody immunoprecipitates. The 100 K MAA was dissociated from albumin in normal human serum by treatment with SDS and fractionation by gel sieving. Under these conditions 100 K MAA from serum co-migrated with similarly treated 100 K from melanoma cells. These results indicate that the 100 K MAA is a normal serum constituent which forms a strong, non-covalent association with albumin and is evolutionarily restricted to higher apes or humans.
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PMID:Monoclonal antibody defined-human melanoma-associated antigens: molecular and phylogenetic studies in normal serum. 665 76

The mRNA for human (tissue type) plasminogen activator from a human melanoma cell line (Bowes) was investigated in different translation systems. After translation of poly(A)-rich RNA in Xenopus oocytes a biologically active plasminogen activator was obtained. Sodium dodecyl sulphate/polyacrylamide gel electrophoresis of the secreted translation products revealed a protein band precipitable with affinospecific antibody and migrating at the same position (apparent molecular mass of approximately 70000 Da) as the native melanoma cell product. Translation in rabbit reticulocyte lysate yielded an immunoprecipitable band migrating at position corresponding to a molecular mass of 52000 Da. Addition of 12-O-tetradecanoylphorbol 13-acetate to the cell cultures resulted in increased production of plasminogen activator. Concomittantly more poly(A)-rich RNA could be extracted from the cells and this RNA was more effectively translated by oocytes into biologically active plasminogen activator. Translation of poly(A)-rich RNA from phorbol-ester-treated cells in the reticulocyte lysate system yielded the 52000-Da protein also seen with RNA from untreated cells. However, in addition a prominent protein band of apparent molecular mass of 48000 Da was detectable. Its intensity increased with increasing doses of tetradecanoylphorbol acetate. This phorbol-ester-induced protein was not precipitable with the affinospecific antibody against plasminogen activator.
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PMID:Effects of 12-O-tetradecanoylphorbol 13-acetate on the production of mRNAs for human tissue-type plasminogen activator. 668 77

Human kidney tumour cells in culture incorporated [3H]glucosamine and 35SO4 into glycoprotein products, which were secreted into the culture medium. The effects of sodium butyrate, a known differentiation-inducing agent, on the production of these sulphated glycoproteins were studied. Cells were cultured in the absence or presence of butyrate (2 mM) in serum-containing medium, for various times, and the labelled glycoproteins were partially purified by DEAE-cellulose chromatography. Treatment of these cells with butyrate resulted in an increase in the synthesis of secreted [3H]glucosamine- and 35SO4-labelled glycoproteins over several days of culture. This same increase in levels of 35SO4 incorporation was not observed with B16 melanoma cells. Sodium dodecyl sulphate (SDS)/polyacrylamide gel electrophoresis revealed that five major glycoproteins labelled with [3H]glucosamine also were labelled with 35SO4. The major secreted glycoproteins from cells cultured in the absence or presence of butyrate over a 3-day period were similar by SDS/polyacrylamide gel electrophoresis. Analyses of Pronase-derived glycopeptides indicated that these secreted 3H/35S-labelled glycoproteins contained sulphated oligosaccharides with terminal sialic acid----Gal----GlcNAc residues similar to glycoproteins secreted by vascular endothelial cells.
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PMID:Secreted glycoproteins of human kidney tumour cells contain sulphated complex-type oligosaccharides. 674 67

The plasminogen activator secreted by a cultured human melanoma cell line was purified and compared with urokinase and with tissue plasminogen activator from human uterus. The purification procedure consisted of chromatography on zinc chelate-agarose, concanavalin A-agarose, and Sephadex G-150 in the presence of 0.01% (v/v) Tween 80. The purified material was obtained from the culture medium with a yield of 46% and a purification factor of 263. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed one main band with a molecular weight of about 72,000, and in the presence of reducing agents, two bands of 33,000 and 39,000. Addition of the protease inhibitor Aprotinin to the culture media and column buffers yielded a one-chain plasminogen activator with a molecular weight of about 72,000. One molecule of activator reacted with about one molecular of [3H]diisopropylfluorophosphate. The melanoma plasminogen activator and the uterine tissue plasminogen activator appeared to be very similar on dodecyl sulfate-polyacrylamide gel electrophoresis, amino acid analysis, and amidolytic properties. Both activators bound to fibrin clots, while urokinase did not. In immunodiffusion, as well as in quenching experiments of the fibrinolytic activities, the melanoma plasminogen activator appeared to be immunologically identical with the uterine tissue plasminogen activator, but unrelated to urokinase. All these findings indicate that the plasminogen activator secreted by human melanoma cells in culture is very similar to, or identical with, the plasminogen activator found in normal tissue, but different from urokinase.
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PMID:Purification and characterization of the plasminogen activator secreted by human melanoma cells in culture. 678 58

In the search for tumor-associated antigens, seven lectins were used to investigate the cellular distribution of membrane-associated glycoproteins on a panel of human cells derived from tumor or normal tissues. Surface labelled lysates of the different cells were precipitated with the lectins and the precipitates were separated on SDS-PAGE. Comparison of the autoradiographic patterns revealed that a La-reactive 115K glycopeptide (gp 115) was present on transitional-cell carcinoma cells of the urinary bladder, on two spontaneously transformed urothelial cell lines and on a melanoma cell line. Gp 115 was absent from a non-transformed urothelial cell line, a squamous bladder carcinoma line and five unrelated cell lines of miscellaneous tissue origin. When precipitation was performed with a rabbit antiserum raised against the La-reactive components of a TCC cell line the same distribution of gp 115 was observed. From Helix pomatia hemagglutinin (HP) precipitates a 150K glycopolypeptide co-migrating with a previously described HP-reactive differentiation antigen associated with human T cells was present on one of the urothelial cell lines and on a colon carcinoma cell line. When different extracts depleted of ConA binding glycopeptides were compared, a group of three antigens (32K, 35K and 40K) were identified in the extracts of the colon carcinoma cell line, HT29. These antigens were shared by two other colon carcinoma cell lines but were absent from the unrelated cells of our panel. Furthermore, an extensively absorbed rabbit anti-HT29 serum specifically precipitated one of these antigens (35K) from the three colon cell lines.
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PMID:Lectins as probes for identification of tumor-associated antigens on urothelial and colonic carcinoma cell lines. 682 54


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