Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

To avoid non-specific binding of intact ricin-antibody conjugates, we prepared a new blocked thioether-linked ricin-antibody IT, in which the galactose binding site of ricin had lost the ability to bind to galactosidic residues of Sepharose 6B gel. As carrier agent, the monoclonal antibody AR-3, which defines the CAR-3 tumour-associated antigenic determinant expressed selectively on different human carcinoma cell lines, was used. Purification of the new conjugate was performed in three sequential steps: (1) by HPLC gel filtration on TSK G3000SW to remove the unconjugated ricin: (2) by affinity chromatography on Affi-Gel Blue to separate the free antibody from the conjugate and (3) by affinity chromatography on Sepharose 6B to separate the galactose-binding IT from the non-binding moiety. The cytotoxicity of the blocked and non-blocked thioether-linked IT was compared with that of classical ricin-antibody IT conjugated via SPDP and that of ricin A chain IT. The comparison was made on two different target cell lines (KATO III human gastric carcinoma and HT-29 human colorectal carcinoma) versus two control cell lines (HL-60 promyelocytic pre-leukaemic and COLO38 melanoma). The results showed that the blocked thioether IT displayed a more selective toxicity to target cells than the non-blocked IT and was much more potent than the ricin A chain conjugate.
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PMID:Comparison of blocked and non-blocked ricin-antibody immunotoxins against human gastric carcinoma and colorectal adenocarcinoma cell lines. 326 8

Melanoma growth stimulatory activity (MGSA) is an acid and heat stable, auto-stimulatory growth factor which was first isolated from culture medium conditioned by the Hs294T human melanoma cell line. In this report, we describe the purification of MGSA from acid ethanol extracts of Hs294T tumors grown in nude mice using a series of Bio-Gel P30, reverse phase-high performance liquid chromatography and heparin-sepharose steps. This modified procedure provides a 10-fold improved yield of MGSA over previously published procedures. Purified MGSA-stimulated melanoma cell growth in both 3H-thymidine and cell number assays over a concentration range of 0.06 to 6 ng/ml. The MGSA bioactivity was primarily associated with fractions which exhibited molecular weights of 16 and 13-14 Kd based upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Purified platelet-derived growth factor (PDGF), insulin-like growth factor (IGF-1), transforming growth factor-beta (TGF beta), and epidermal growth factor (EGF) in combination with TGF beta did not stimulate 3H-thymidine incorporation in Hs294T cells under the conditions used for MGSA bioassay. Monoclonal antibody to MGSA was used to screen melanoma and benign nevus cultures as well as fixed sectioned tissue for MGSA. The majority of the melanoma cultures were MGSA positive, while most nevus cultures were MGSA negative. However, when fixed sectioned tissue was screened for MGSA immunoreactivity, melanoma tissue was MGSA positive and three-fourths of the benign nevi were MGSA positive. In addition, epidermal keratinocytes and several tissues exhibiting proliferative disorders contained immunoreactive MGSA. These data suggest that MGSA may be a normal regulator of growth and that the microenvironment of the cell may regulate both production of MGSA and response to MGSA.
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PMID:Melanoma growth stimulatory activity: isolation from human melanoma tumors and characterization of tissue distribution. 335 54

24 established melanoma cell cultures were screened for their secretion of plasminogen activators and plasminogen activator inhibitors into the culture medium by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by conventional and reverse fibrin autography. Among the cell lines investigated, 22 cell lines predominantly secreting tissue type plasminogen activator (t-PA) and four cell lines additionally secreting urokinase were found. The conditioned media of two cell lines (KRFM and MJZJ) were found to contain plasminogen activator inhibitor (PAI) activity at a Mr position of approximately 50,000. The PAI of one of the two melanoma cell (MJZJ)-conditioned media found to contain PAI activity was purified to apparent homogeneity employing concanavalin A-Sepharose chromatography, gel filtration on Sephadex G-150, chromatography on Affi-Gel blue, and affinity chromatography on a Sepharose 4B immobilized monoclonal anti-t-PA IgG column. The purified melanoma PAI was found to be a single chain protein, acid stable, immunologically related to the endothelial derived PAI. In contrast to endothelial PAI, melanoma PAI presented itself in the conditioned media of the melanoma cells and in the purified preparation to an appreciable extent in its active form.
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PMID:Purification of an active plasminogen activator inhibitor immunologically related to the endothelial type plasminogen activator inhibitor from the conditioned media of a human melanoma cell line. 349 Apr 74

Challenge of human A375 melanoma cells with sodium arsenite induced the synthesis of stress proteins and stimulated [3H]mannose incorporation into a novel component migrating on sodium dodecyl sulfate-polyacrylamide gel electrophoresis with an apparent molecular mass of 14 kDa (designated M14). Enhanced M14 expression was elicited by heavy metals (zinc, copper, cadmium, and nickel), thiol-reactive agents (iodoacetamide and auranofin), and hyperthermia. The kinetics of M14 induction and recovery from stress were similar to those of the stress proteins, but M14 half-life was only 15 min. Incorporation of [3H]mannose into M14 was inhibited by tunicamycin but not by cycloheximide or actinomycin D. M14 was metabolically labeled with [32P]orthophosphate but not by [35S] methionine or [3H]asparagine. Further studies revealed that M14 was selectively soluble in chloroform/methanol/water (10:10:3) and sensitive to both endo-beta-N-acetylglucosaminidase H digestion and mild acid hydrolysis. The latter released a water-soluble mannose-labeled moiety which eluted from Bio-Gel P-6 in a manner similar to Glc3Man9GlcNAc2. Together, these data suggest that M14 is a lipid-oligosaccharide intermediate of N-linked protein glycosylation and that enhanced expression of this class of molecule in response to chemical insults and hyperthermia is a newly described cellular reaction to stress.
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PMID:Alterations in lipid-linked oligosaccharide metabolism in human melanoma cells concomitant with induction of stress proteins. 366 5

The ability of cellular vascular components including endothelial cells, smooth muscle cells, and fibroblasts to interact with the collagenolytic activity of invasive human tumor cell lines has been investigated. The human HT1080 fibrosarcoma and Bowe melanoma cells, which rapidly digest collagenous proteins in vitro, failed to dissolve them when cocultivated with bovine endothelial cells. This inhibition was not dependent on the ability of endothelial cells to form a monolayer separating the tumor cells from the collagenous substrate. In contrast, little collagenolysis inhibitory activity was detected in bovine vascular smooth muscle cells and human fibroblasts when compared to endothelial cells. Serum-free medium conditioned by endothelial cells inhibited tumor cell-mediated collagenolysis. Our data further suggest that this inhibition was mediated by secreted collagenase inhibitors, since endothelial cell-conditioned medium did not suppress the production of metalloproteinases by the tumor cells but inhibited the activities of collagenases derived from tadpole, rabbit, and human fibroblasts. Treatment of the endothelial cells with cycloheximide suppressed the collagenase inhibitory activity, demonstrating active production of collagenase inhibitors by the cells. Gel filtration chromatography of endothelial cell-conditioned medium allowed the separation of two distinct peaks with inhibitory activities for vertebrate collagenase in the molecular weight range of 70,000 to 75,000 and 30,000 to 35,000, respectively. While the inhibitor with an approximate molecular weight of 30,000 to 35,000 shared many properties with the tissue inhibitor of metalloproteinases, the high-molecular-weight inhibitor demonstrated characteristics not yet described for any collagenase inhibitor. The production and secretion of inhibitors of vertebrate collagenase by bovine endothelial cells may be of importance in the local control of collagen turnover under physiological as well as pathological conditions.
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PMID:Inhibition of tumor cell collagenolytic activity by bovine endothelial cells. 370 89

Serum-free growth of the human malignant melanoma cell line Hs0294 is associated with production of transforming growth factor-alpha and an autostimulatory melanoma mitogen (melanoma growth-stimulatory activity, MGSA). The transforming activity is characterized by stimulation of anchorage-independent growth of normal rat kidney fibroblasts and competition with 125I-epidermal growth factor for binding to normal rat kidney cells. The second activity, MGSA, stimulates the anchorage-dependent growth of human melanoma cells in serum-free culture medium. When acetic acid extracts of Hs0294 conditioned medium are subjected to Bio-Gel P-30 chromatography followed by reverse-phase high-pressure liquid chromatography, the majority of the transforming growth factor-alpha elutes at 30 +/- 4% acetonitrile, while the major peak of MGSA elutes at 35 +/- 3% acetonitrile. These data indicate that the anchorage-dependent serum-free growth of the Hs0294 human melanoma cell line is apparently dependent upon the autostimulatory melanoma mitogen, MGSA, which is separable from the 125I-epidermal growth factor competing activity produced by these cells.
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PMID:Characterization of autostimulatory and transforming growth factors from human melanoma cells. 386 31

Human extrinsic plasminogen activator (EPA), highly purified from a melanoma cell culture fluid is inactivated in human plasma with a half-life (t 1/2) of 90-105 min. Gel filtration on Ultrogel AcA 34 of mixtures of 125I-labeled EPA and human plasma, incubated at 37 degrees C, revealed the progressive formation of two radioactive components, one with an apparent Mr of 150,000 and one eluting at the void volume. The component with an Mr of 150,000 was identified as consisting at least in part of EPA-alpha 2-antiplasmin complex since: 1) it reacted with antibodies against alpha 2-antiplasmin, but not with antibodies against the other known plasma protease inhibitors, and 2) formation of this component was strongly reduced in plasma specifically depleted in alpha 2-antiplasmin or when the active site of EPA was blocked. The component eluting at the void volume was identified as consisting at least in part of EPA-alpha 2-macroglobulin complex since: 1) it only reacted with antibodies against these two proteins and 2) was not formed in plasma depleted in alpha 2-macroglobulin or when the active site of EPA was blocked. In purified systems alpha 2-antiplasmin inhibited one-chain EPA with a rate constant of 60 M-1s-1 and two-chain EPA with a rate constant of 130 M-1s-1, which corresponds to a t 1/2 in plasma of 180 min or 90 min, respectively. alpha 2-Macroglobulin inhibited one-chain EPA with a rate constant of 15 M-1s-1 and two-chain EPA with a rate constant of 30 M-1s-1, which corresponds to a t 1/2 in plasma of 4 or 2 hrs. All these findings taken together indicate that EPA is slowly neutralized in human plasma primarily by alpha 2-antiplasmin and to a lesser extent by alpha 2-macroglobulin. There appears to be no specific inhibitor in human plasma, which would inactivate EPA either rapidly or to a significant extent.
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PMID:Neutralization of human extrinsic (tissue-type) plasminogen activator in human plasma: no evidence for a specific inhibitor. 617 7

Ethanol precipitate (70-95%) of the water extract of mouse melanoma (ME) contains suppressors for melanocyte cell division. A fraction which had preferential melanocyte cell line suppressor activity (ME IV2) was shown to inhibit protein synthesis by cell-free systems and RNA synthesis by isolated nuclei of rat liver. The separation and some characterization of the inhibitory factors in ME IV2 were carried out. Upon being boiled, the factor in ME IV2 inhibiting cell-free protein synthesis became inactive, whereas that inhibiting cell-free RNA synthesis remained active. Bio-Gel p-2 column chromatography of ME IV2 gave three distinct fractions (ME IV2-A, -B and -C). ME IV2-A was inhibitory to cell-free protein synthesis but non-inhibitory to cell-free RNA synthesis. On the contrary, ME IV2-B was non-inhibitory to cell-free protein synthesis but inhibitory to cell-free RNA synthesis. ME IV2-C was non-inhibitory to cell-free protein synthesis and seemed to be somewhat inhibitory to cell-free RNA synthesis. Preliminary analyses of the components in these subfractions are also reported.
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PMID:Inhibition of cell-free protein and RNA syntheses by partially purified fractions of mouse melanoma extract. 617 8

A cell surface glycoprotein receptor for nerve growth factor (NGF) has been identified by covalent crosslinking to 125I-labeled NGF (125I-NGF). Either ethyldimethylisopropyl-aminocarbodiimide or hydroxysuccinimidyl-p-azidobenzoate causes highly specific crosslinking of 125I-NGF to a similar receptor species on rat pheochromocytoma PC12 cells and on human melanoma A875 cells. The NGF-receptor complex migrates as a broad band in NaDodSO4/polyacrylamide gel electrophoresis with an apparent Mr of approximately equal to 100,000. Because the NaDodSO4-denatured complex apparently contains a single Mr 13,000 NGF chain, the apparent molecular weight of the receptor itself is 87,000. Inhibition of protein glycosylation by tunicamycin generates smaller 125I-NGF-receptor complexes. The mobility of the smallest of these in NaDodSO4 gel electrophoresis corresponds to a Mr of 90,000 for the complex and, hence, 77,000 for the carbohydrate-deficient receptor. A second NGF-receptor complex with a Mr of 225,000 also is obtained from A875 cells but only occasionally from PC12 cells. Tunicamycin treatment decreases the molecular weight of these species by 10,000-15,000. Substantial purification of the Mr 100,000 NGF-receptor complex was achieved by lectin affinity chromatography on columns of wheat germ agglutinin linked to Affi-Gel 15. The specific absorption of NGF-receptor complexes to these columns indicates that the receptor is a glycoprotein that contains N-acetyl-D-glucosamine.
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PMID:Affinity labeling and partial purification of nerve growth factor receptors from rat pheochromocytoma and human melanoma cells. 631 27

A melanoma tumor-associated antigen (TAA), isolated from spent culture medium of human melanoma cell line UCLA-SO-M14, was purified to mean homogeneity to determine its physical and biochemical nature. Gel filtration and native polyacrylamide gel electrophoretic analyses of the 125I-labeled melanoma TAA revealed that the antigen had a molecular weight in the range of 180,000-190,000. However, ultracentrifugation of melanoma 125I-labeled TAA in a 5-20% sucrose density gradient revealed a sedimentation coefficient to be 4.96 +/- 0.24. Melanoma 125I-labeled TAA focused at a pH of 6.5 by isoelectric focusing. No carbohydrates were detectable by various colorometric methods in the highly purified melanoma TAA fraction, and melanoma TAA failed to bind with several lectins. Its antigenic activity was destroyed by the proteolytic enzymes but was not affected by the glycosidic enzymes or phospholipase A2. The results suggested that the melanoma TAA was most likely a lipoprotein that had a molecular weight of 180,000-190,000, a sedimentation coefficient of approximately 5, and a pl value of 6.5. The protein portion apparently formed the antibody binding site(s).
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PMID:Studies of a melanoma tumor-associated antigen detected in the spent culture medium of a human melanoma cell line by allogeneic antibody. III. Physicochemical properties. 658 6


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