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

Analysis of a number of B16 melanoma clones has revealed a high correlation between metastatic activity and the quantitative expression of a 72,000 dalton glycoprotein, Met 72. In the present study, metastatic tumor cell variants have been directly isolated from a heterogeneous, poorly metastatic melanoma (B16-F1) by anti-Met 72 monclonal antibodies and cell sorting procedures. These studies provide direct proof that Met-72 antigens are in fact surface markers of B16 melanoma metastatic variants and may provide the means of monitoring their presence, influence and autonomy during tumor progression.
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PMID:Isolation of metastatic B16 melanoma variants using anti-Met 72 monoclonal antibodies and flow cytometry. 382 95

The antitumor effect of methionine-enkephalin [( Met]enkephalin) was demonstrated in C57BL/6J mice inoculated with B16-BL6 melanoma cells. Local subcutaneous tumor growth was inhibited with a 50-micrograms dose daily for 7 or 14 days. The antitumor effect of [Met]enkephalin was inhibited by the administration of the opioid receptor antagonist naloxone. Naloxone alone had no significant effect on tumor growth.
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PMID:Inhibition of B16-BL6 melanoma growth in mice by methionine-enkephalin. 386 Jun 86

A series of seven monoclonal antibodies recognizing cell surface antigens of similar distribution on a panel of leukemia/lymphoma and lymphoblastoid human cell lines was prepared by hybridoma technique after immunization with non-T, non-B acute lymphoblastic leukemia cell line REH. Immune reactivity of these monoclonal antibodies with B-lymphoblastoid and lymphoma cell lines, as well as with non-T, non-B leukemia cell lines but not with T-leukemic and myeloid leukemic cell lines (with the exception of myeloid leukemia cell line KG 1) was demonstrated by indirect immunofluorescence. No reactivity was observed with the examined human non-hemopoietic tumor cell lines, except melanoma cell lines HMB-2 and SK 1477. These antibodies immunoprecipitated a similar cell surface bimolecular glycoprotein complex consisting of two glycosylated chains (gp30, 35), as demonstrated by immunoprecipitation of cell surface 125I-lactoperoxidase radioiodinated, periodate/tritiated borohydride radiolabeled and 35S-methionine metabolically radiolabeled proteins of REH cells. These properties, typical of MHC class II antigens correspond also to immunoperoxidase staining of lymph nodes with some selected antibodies.
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PMID:Monoclonal antibodies against MHC class II antigens elicited with a human non-T, non-B acute lymphoblastic leukemia cell line. 391 Oct 80

Most vitiligo sera contain antibodies to surface antigens on pigmented human melanocytes but not to human or mouse amelanotic melanoma cells. A density-dependent line of hamster amelanotic melanocytic cells (FF) produces a diffusible factor (CIF) which restores contact inhibition of growth as well as several other normal phenotypic characteristics to hamster, murine, and human melanoma cells. The ability of CIF to induce the expression of a phenotypic characteristic of pigmented human melanocytic cells, i.e., the vitiligo-related surface antigens, on hamster and mouse amelanotic melanoma cells was investigated. Vitiligo and normal sera were reacted with CIF-treated and untreated hamster and mouse amelanotic melanoma cells for both indirect-immunofluorescence assays and ELISA. Immunofluorescence testing showed that about 80% of hamster and mouse melanoma cells had pigment-cell antigens (in the absence of pigmentation) in a granular surface pattern after, but not prior to, CIF-induced morphologic reversion and confluent growth. Less than 5% of the control hamster and mouse melanoma cells expressed such antigens at confluence. These results were confirmed by ELISA. Metabolic-labeling studies with 35S-methionine showed that the vitiligo antigens were synthesized by the CIF-treated melanoma cells. The slowing of melanoma cell proliferation in isoleucine-deficient medium failed to elicit the expression of vitiligo antigens. Since antigen appearance following phenotypic reversion occurred without pigment induction, it is concluded that vitiligo-related surface antigens and pigmentation are distinct aspects of a differentiated function which may be non-coordinately expressed. The expression of pigment-cell differentiation antigens on amelanotic melanoma cells is an additional feature of the pleiotypic trans-species response to CIF.
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PMID:Vitiligo-related pigment cell differentiation antigens are expressed on malignant melanoma cells following phenotypic reversion induced by contact inhibitory factor. 391 44

Pigmented melanoma cells and cultured melanocytes express a differentiation-related glycoprotein designated as pigmentation-associated antigen (PAA) of Mr 70,000-80,000. As described previously, PAA was initially defined by reactivity with antibodies in the serum of a patient with melanoma. Here we describe the production and characterization of a mouse monoclonal antibody to PAA. This antibody (TA99, an IgG2a) was shown by sequential immunoprecipitation experiments to react with the same component as the human antibody. Ab TA99 immunoprecipitated PAA from lysates of cells radiolabeled with [35S]methionine, [3H]glucosamine, [3H]fucose, and [3H]mannose as well as 125I. Using Ab TA99, the distribution of PAA was examined in frozen sections of 19 normal tissues and quantitatively in 68 tissue culture cell lines. In frozen sections, only melanin-containing cells were positive, including epithelial cells in the basal layer of the epidermis, in which pigment originates from melanocytes by transfer of melanosomes, and pigmented cells of the eye. In tissue culture cell lines, only pigmented melanoma cells were positive. PAA is an intracellular antigen, with a distribution very similar to that of melanosomes. This evidence confirms the close association of PAA with melanin production, and suggests that PAA may be a melanosome component. PAA was shown to be different from tyrosinase, the enzyme involved in melanin synthesis, but it was found to be identical to the previously recognized glycoprotein, gp75, characteristic of pigmented melanomas and melanocytes.
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PMID:Pigmentation-associated glycoprotein of human melanomas and melanocytes: definition with a mouse monoclonal antibody. 392 6

Tunicamycin, an inhibitor of glycosylation, was used to examine whether glycosylation is required for shedding of tumor antigens and other macromolecules by human melanoma cells. Cellular proteins were labeled with [35S]methionine, glycoproteins with [14C]glucosamine, and external surface components with 125I by the lactoperoxidase method; 0.5 and 2.5 microgram tunicamycin/ml effectively inhibited glycosylation without significantly reducing protein synthesis. We found that release of labeled macromolecules in the presence or absence of tunicamycin was similar. Tunicamycin-treated cells released 10.2% of [35S]methionine, 29.8% of [14C]glucosamine, and 57.2% of 125I-labeled macromolecules in 24 h compared to 5.5, 14.9, and 50.8%, respectively, for untreated control cells; 62.5% of the radioactivity associated with cell-surface melanoma-associated antigens defined by specific antiserum were released in 24 h as opposed to 50.4% by untreated cells. These results indicate that release of many cellular proteins, including glycoproteins, external surface proteins, and some melanoma-associated antigens, does not require glycosylation.
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PMID:Effect of tunicamycin on release of macromolecules and tumor antigens by human melanoma cells. 397 39

A 140 K glycoprotein was detected in the culture media of human sarcoma and melanoma cell lines by labeling with several radioactive amino acid and sugar precursors, followed by sodium dodecylsulfate-polyacrylamide gel electrophoresis and fluorography. In contrast to this, in the culture media of metabolically labeled embryonic and skin fibroblasts this glycoprotein was not found. Likewise, a protein with an identical molecular weight of 140 K was also found in culture media after cell surface labeling of the neoplastic cells but not in the culture media from control cells. The [35S]methionine-labeled 140 K was not split by collagenase and did not appear to be a fragment of fibronectin. We discuss the possibility that secretion of the 140 K glycoprotein is a transformation-related phenomenon.
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PMID:Release of an Mr 140,000 glycoprotein in the culture media of certain human sarcoma and melanoma cell lines. 400 10

A murine monoclonal antibody (9.2.27), directed to a Mr 250,000 glycoprotein-chondroitan sulfate proteoglycan complex, was radiolabeled with 125I and assessed for radiolocalization in tumor and normal tissues of normal and tumor-bearing nude mice. The 125I-9.2.27 localized in vivo preferentially in Mr 250,000 antigen-expressing human melanomas (FMX-Met, SESX) but not in low antigen-expressing tumors (LOX-L) xenografted in nude mice. The imaging index of tumor cells was positively correlated with the antigen density of the various melanoma cell lines as measured by flow cytometry. The nonspecific immunoglobulin RPC-5 of the same IgG2a subclass as 9.2.27 did not specifically localize to xenografts of melanoma. The total amount of 125I-9.2.27 accumulated in the tumor was directly correlated with tumor size. However, the specific radioactivity (cpm/g) in smaller tumors was higher than that in larger tumors. Nonspecific uptake and circulating antibody levels differed between normals and tumor-bearers. The organs of the reticuloendothelial system of normal mice accumulated more labeled antibody than did those of tumor bearers, and conversely, tumor bearers had higher levels of circulating labeled antibody in the blood than normals. The circulating labeled antibody in tumor bearers was still monomeric but had no detectable antigen-binding capacity.
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PMID:Radiolocalization of xenografted human malignant melanoma by a monoclonal antibody (9.2.27) to a melanoma-associated antigen in nude mice. 402 7

B16 melanoma cells exhibited decreased adhesion to substration and the presence of cytoplasmic granules, resembling lipid inclusions, when cultured in vitro in the presence of syngenic serum from C57/BL6 mice. This constrasted with the rapid cell attachment and absence of cytoplasmic granules in cultures seeded in medium supplemented with an identical concentration of fetal bovine serum. Electrophoretic comparison of intracellular proteins revealed similar patterns in detergent-soluble and matrix-associated proteins from cells grown with bovine or mouse serum. However, a similar analysis of the conditioned media showed clear differences in methionine-rich species which migrated in the 100 kd region in cells grown with bovine serum, and as 110 kd component in cells grown with mouse serum. Our data indicate that the poor attachment to substratum and changes in cytoplasmic organization of B16 melanoma cells, is primarily associated with specific changes in secreted proteins.
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PMID:Serum mediated changes in cell attachment and cytoplasmic organization of B16 melanoma correlates with selective alterations in secreted proteins. 406 21

Vesicular stomatitis virus (VSV), when reproduced in human tumor cell lines, assembled a specific subset of cell-derived proteins. These were detected by 35S]methionine labeling of cells prior to infection and subsequent immunoprecipitation of VSV grown in these cells, as well as by direct immunoprecipitation of labeled cell extracts with antiserum directed against the VSV-assembled proteins. Their molecular weight (Mr) ranged between 15K and 180K; the larger proteins were glycosylated. Two of the major protein species (gp88 and gp130) were common to all four cell lines used (HeLa-cervical carcinoma, T47D-breast carcinoma, and HMB2 and SK1477-two melanoma cell lines). Proteins of other molecular weights were detected only in one or two of the cell lines. The melanoma cell lines (even in the absence of VSV) shed large particulate material which had contained the same spectrum of proteins that were assembled by VSV. The major protein component had an Mr of 30K. Some of the VSV-assembled proteins might possibly serve as specific tumor markers. It is also conceivable that the proteins assembled by VSV as well as the large particulate material might be products of defective endogenous human retroviruses.
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PMID:Further characterization of proteins assembled by vesicular stomatitis virus from human tumor cells. 609 57


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