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

Biochemical characterization of serologically detected human melanoma antigens was undertaken for the development of immunodiagnostic assays in melanoma. An antiserum from a human melanoma patient, which detected melanoma antigens expressed on a large proportion of different melanoma cells, was used in leucocyte-dependent cytotoxic antibody (LDA) 51Cr-release assays to monitor the purification of melanoma antigens in urea/acetate extracts of lactoperoxidase 125I-labelled melanoma cell membranes. The separation procedures included affinity chromatography on Concanavalin A, gel filtration on porous polyacrylamide beads and preparative isoelectric focusing. The fractions were also monitored by polyacrylamide electrophoresis in sodium dodecyl sulphate and by measurement of beta 2 microglobulin and carcinoembryonic antigen content. The antigens detected by this antiserum appeared to be acidic (pI 3.5) low-mol.-wt glycoproteins of approximately 15,000 daltons which were resistant to heating at 56 degrees C and digestion with neuraminidase, but susceptible to repeated freeze-thawing and trypsin digestion. They did not appear to be related to HLA antigens, beta 2 microglobulin or known foetal antigens. The nature of the antigens detected in these studies is as yet unknown, but they appear similar to those described in the sera and urine of melanoma patients in previous reports. Thes combined results and the frequent expression of these antigens on melanoma cells from different patients suggest that assays to detect this antigen may provide a valuable immunodiagnostic aid in the management of melanoma.
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PMID:Detection of a low-molecular-weight antigen on melanoma cells by a human antiserum in leukocyte-dependent antibody assays. 9 79

Guinea-pig melanocytes in mixed epidermal cell cultures bind melanocyte-stimulating hormone in a distinct focal surface area in their perinuclear field and thus follow the same pattern previously described for Cloudman melanoma cells. The labeling index ranged from 18 to 34%. Pretreatment of cultures with trypsin leads to destruction of melanocyte-stimulating hormone receptors whereas neuraminidase has no such effect.
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PMID:Melanocyte-stimulating hormone receptors on cultured guinea-pig melanocytes. 18 12

Samples of 35 tumors from the head and neck region (25 squamous cell, 2 basal cell, 5 parotid, 3 melanoma, and 1 lymphosarcoma) were cultured after dispersement with either trypsin or collagenase treatment. Growth was established in 14 (40%). Cultured tumor cells were then used as target cells in in vitro assays of patients' cellular and humoral immunity to their own or similar tumors. Preliminary data suggest this may be a reliable method of monitoring responses in patients receiving immunotherapy for head and neck malignancies.
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PMID:Tissue-cultured head and neck tumors: their use in in vitro assays of immune response. 19 78

Cell lines derived from human malignant melanoma tumors are susceptible to infection with varicella-zoster virus (VZV). Within 5 days after inoculation of vesicular fluid, cytopathic changes appeared in melanoma cell monolayer cultures that were incubated at either 36 or 32 degrees C. The VZV isolates at the two temperatures were serially propagated by passage of trypsin-dispersed infected cells. A plaque assay was developed utilizing melanoma cell monolayers overlaid with nutrient medium containing carboxymethylcellulose. By this assay method, the growth cycle of a VZV isolate propagated at 36 degrees C was studied and compared with that of another VZV isolate grown at 32 degrees C. With equivalent infected-cell inocula at a ratio on one inoculum cell to eight uninfected cells, the yield of cell-free virus at an incubation temperature of 32 degrees C was slightly higher than at 36 degrees C, although the peak occurred 60 h, rather than 36 h, postinfection. It was also found that the titer of low-passage VZV propagated at 36 degrees C was 0.5 to 1 log higher when assayed at 32 degrees C rather than at 36 degrees C.
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PMID:Varicella-zoster virus: isolation and propagation in human melanoma cells at 36 and 32 degrees C. 20 32

In poeciliid fish, melanoma of different degrees of malignancy can be produced by crossing specific genotypes. For a detailed investigation of the processes leading to proliferation or differentiation of the melanoma cells, it is necessary to establish cell cultures. The aim of the present study was to find out the optimal conditions for initiating and culturing poeciliid fish cells for the purpose of establishing cell cultures of melanoma. The optimal method was developed by using small pieces of late embryos as starting material and includes: (a) dispersion of tissue by mild stepwise treatment with a trypsin-EDTA mixture at low temperature; (b) culture of cells in the complex medium 199; (c) supplementation of medium with high percentage (20%) of fetal bovine serum; and (d) stabilization of pH by buffering the medium with HEPES. Under these conditions, primary and secondary cultures of embryonic cells have been initiated. An epithelial-like cell line has been subcultured for more than 80 passages. The method developed for embryonic tissues was used to start cell cultures from melanoma of platyfish-swordtail hybrids. Until now, only cells of rapidly growing malignant albino melanoma could be maintained in primary cultures. Secondary cultures could not be initiated since the melanoma cells tended to differentiate and stopped growing before a confluent monolayer was formed.
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PMID:Cell cultures derived from embryos and melanoma of poeciliid fish. 52 10

The effect of ketone bodies on the growth, in culture, of transformed lymphoblasts (Raji cells) was investigated. Cell growth was inhibited and this effect was reversible, non-toxic, and proportional to the concentration of D-beta-hydroxybutyrate up to 20mM. The total glucose utilisation and the total lactate production were reduced in proportion to the inhibition of cell proliferation. D-beta-hydroxybutyrate was not metabolised by the cells. Other glycolytic inhibitors and chemical analogues of D-beta-hydroxybutyrate either did not inhibit or proved to be too toxic for cell growth. D-beta-hydroxybutyrate also inhibited the growth of rabbit kidney (RK13), HeLa, mouse melanoma (B16), fibroblast and trypsin-dispersed human thyroid and beef testis cells. Moreover, in vivo dietary-induced ketosis reduced the number of B16 melanoma deposits in the lungs of C57BL/6 mice by two-thirds. The significance of these results in the clinical management of cancer cachexia is discussed.
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PMID:The inhibition of malignant cell growth by ketone bodies. 54 19

The cell-surface proteins of 6 different melanoma cell cultures have been labelled with 125I using lactaperoxidase-catalysed iodination. Fractionation of the proteins was achieved using 5--22.5% polacrylamide-gradient gel electrophoresis in the presence of sodium dodecyl sulphate (SDS) and the proteins were detected by autoradiography. Up to 24 labelled proteins were detected in the individual cell cultures, but the proteins labelled differed considerably in the 6 cultures examined. A possible reason for this, involving variation in the glycosylation of cell-surface glycoproteins is discussed. Cells of the same melanoma line had similar cell-surface proteins at different passage levels, but changes in the labelled proteins occurred when the culture conditions were altered. The cell-surface proteins of high molecular weight were cleaved by trypsin, but most of the low mol.-wt. proteins were resistant to trypsin. The "large external transformation sensitive" (LETS) protein detected as a major protein on fibroblasts in culture was not a dominant protein on the melanoma cells. It was detected on only 4/6 cell cultures. Possible relationships of the cell-surface proteins described in this study to morphology, immunological properties and proteolytic activity of human melanoma cells are discussed.
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PMID:Lactoperoxidase-catalysed iodination of surface proteins on human melanoma cells. 68 8

Melanosomal "tyrosinase" (L-dopa) was isolated from trypsin digest of B-16 mouse melanoma melanosomes, using polyacrylamide gel disc electrophoresis. The enzyme was represented by a single band, having characteristics similar to the T1 dopa-positive band observed when using supernatants of crude melanoma homogenates as the source. When gels with this band were incubated in solutions containing tyrosine and dopa in varying ratios , there was no enhancement of melanin formation by tyrosine when compared with incubations in corresponding concentrations of dopa alone. These data further support previous studies in our laboratory demonstrating an inability of so-called mamalian "tyrosinase" to convert tyrosine to melanin; since this enzyme readily converts L-dopa to melanin, it seems more reasonable to term this enzyme an L-dopa oxidase.
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PMID:Inability of murine melanoma melanosomal "tyrosinase" (L-dopa oxidase) to oxidize tyrosine to melanin in polyacrylamide gel systems. 80 38

The T1 variety of tyrosinase is present in both particulate and soluble or readily solubilized forms in the pigmented hypodermis (hair bulbs) of C57BL mice and Harding-Passey mouse melanoma. Trypsin treatment of 35,000g supernatants containing the microsomal (small granule) fraction of gentle homogenates of hair bulbs and melanoma results in significantly increased T1 activity within polyacrylamide gels. Similar treatment of 100,000g supernatants results in a slight increase in T1 activity. Addition of Triton-X or DOC to 35,000g supernatants of hair bulb and melanoma homogenates followed by centrifugation at 100,000g results in a marked enhancement of T1 when the latter supernatants are treated with trypsin. In the absence of trypsin treatment, T1 activity is comparable to nondetergent-treated controls. A slow-moving dopa-reactive band (Ts) is found in electropherograms of the nontrypsinized 100,000g supernants of detergent-treated 35,000g supernatants. It is absent in those treated with trypsin. The slow-moving enzyme appears to give rise to T1 molecules when eluted from acrylamide gels and even to a greater extent when elution is combined with trypsin treatment prior to reelectrophoresis. In mammals, tyrosinase apparently is not derived by a proteolytic activation of protyrosinase.
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PMID:Action of trypsin and detergents on tyrosinase of normal and malignant melanocytes. 81 38

A chimpanzee anti-human melanoma antiserum was used to study the enzymatic susceptibility and spontaneous release into tissue culture medium of human melanoma tumor-associated antigens (TAA). Limited proteolytic digestion of melanoma cells with trypsin or with pronase rendered these cells refractory to lysis by the chimpanzee antiserum and complement. Longer periods of incubation of higher concentrations of enzyme caused an increased sensitivity to lysis. Digestion of melanoma cells with neuraminidase apparently exposed antigens reactive with natural antibodies in rabbit complement because cells so treated had a marked increase in sensitivity to cytolysis. Absorption of the complement with either neuraminidase-treated human melanoma cells or washed human spleen cells prior to its use in the cytotoxicity assay removed this activity. When absorbed complement was used, neuraminidase had no noticeable effect on the expression of malanoma TAA. These results suggest that proteolytic digestion of melanoma cells may prove to be a useful means of solubilizing TAA. The spontaneous release of melanoma cell membrane TAA was studied. Protein precipitated by (NH4)2SO4 from four of six samples of tissue culture medium used to feed malanoma cell lines contained significant antigenic activity compared to a control "antigen" preparation, whereas one preparation contained only limited TAA activity. One melanoma cell line that apparently failed to release TAA into the culture medium had previously become nonreactive with the chimpanzee antiserum. From these data, we conclude that melanoma cells growing in tissue culture rapidly release large amounts of TAA into the culture media and, as a result, the spent culture medium may be a good source for obtaining TAA for further study. The significance of these results is discussed.
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PMID:Enzymatic susceptibility and spontaneous release of human melanoma tumor-associated antigens. 83 72


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