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

A study of glycoprotein components in trypsin-digested material from the surface of isolated melanotic melanoma cells showed presence of amino sugars, protein-bound hexoses, fucose and sialic acids. The high content of fucose and low content of sialic acids in the surface material from the cells were striking.
 ...
PMID:Surface glycoprotein components in isolated melanotic melanoma cells in the golden hamster. 87 93

We have established conditions for the study of membrane glycoprotein synthesis and turnover in cultured human malignant melanoma cell lines using the labeled precursor [3H]glucosamine. Uptake of label increased parallel with cell growth, reaching a steady state in resting cultures. Fifteen to 30% of incorporated label can be released from the cells by trypsin treatment depending on the conditions of exposure to the enzyme, and about 50% of the incorporated label is spontaneously shed from the cells within 96 hr of incubation. Labeling in exhausted medium gave a 5- to 8-fold increase in uptake which was inhibited by addition of glucose (2 mg per ml) into the culture medium. The percentage of trypsin-releasable material was identical in fresh and exhausted medium; however, the percentage shed was less in cells initially labeled in exhausted medium. These data provide background information for further studies on the antigenic composition of the glycoproteins of cultured melanoma cells.
 ...
PMID:Characterization of human malignant melanoma cell lines. VII. Glycoprotein synthesis and shedding as revealed by [3H]glucosamine labeling. 92 59

A suspension of melanoma cells isolated non-enzymatically from tumors (melanotic and amelanotic) of transplantable melanoma in Syrian hamster was treated with trypsin to obtain surface material. In the material released from the cell surface contents of protein, aminosugars, fucose, sialic acids and hexoses were determined. Differences in the composition of the surface material derived from two kinds of melanoma were observed. The differences in the surface glycoprotein composition seem to be related to biological properties of both melanomas.
 ...
PMID:Comparison of the surface glycoprotein components in the isolated cells of hamster melanotic and amelanotic melanomas. 96 90

A patient with adult-onset diabetes mellitus was referred with a diagnosis of malignant melanoma of the choroid of the left eye. A nonproliferative type of diabetic retinopathy was present, which was studied and documented by stereoscopic fundus photographs and fluorescein angiograms. Following enucleation, the microangiopathies were correlated histologically, using the retinal trypsin digest technique. Four types of microaneurysms were seen histologically that were believed to represent stages in the development of this lesion. Most thin-walled aneurysms tightly packed with erythrocytes did not fluoresce. Aneurysms that were hypercellular and those with thick walls showed early and late fluorescence. Intraretinal microvascular abnormalities were hypercellular dilated channels. Those that take origin from terminal arterioles are believed to represent attempts at neovascularization.
 ...
PMID:Clinicopathologic correlations in diabetic retinopathy. I. Histology and fluorescein angiography of microaneurysms. 97 22

A clone of Cloudman S91 murine melanoma was fused in vitro with non-malignant hamster cheek pouch cells by means of lysolecithin, and the putative hybrid progeny cells, HCP-MM, were found to be highly malignant in hamster, but not in appropriate mice. A malignant clone of HCP-MM cells was shown to have hamster species-specific surface antigens (as demonstrated by immunofluorescence and the cytotoxic antibody) and hamster-like lactate dehydrogenase and NAD-dependent malate dehydrogenase isoenzyme profiles. Nevertheless, chromosomes similar to those of both murine and hamster parental cells could be distinguished in cells of this malignant clone and in hamster tumor grafts by the method of trypsin-Giemsa banding. A majority of the murine chromosomes, however, appeared to be lost. This study indicates that a murine melanoma previously found untransplantable in hamsters could produce a highly malignant and lethal tumor for hamsters after being mixed in vitro with non-malignant hamster cells, in the presence of a fusing chemical. It is not as yet certain whether the production of transformed cells in vitro and of highly malignant tumors in the hamster (both with predominantly hamster properties) required heterosynkarion formation between the murine melanoma and hamster cheek pouch cells. Nevertheless, our results suggest that the presence of the murine melanoma, and possibly the interaction of its genome with non-malignant hamster cells, was implicated in this process.
 ...
PMID:Oncogenesis by interspecific interaction of malignant murine and non-malignant hamster cells in vitro. 109 20

A serum-dependent and two serum-independent variants of the Bowes melanoma cell line, RPMI7272, were transfected with plasmids containing a geneticin-resistance (neo) gene transcribed by the HSV thymidine kinase promoter and an SV40 T antigen gene under control of the mouse metallothionein I promoter. T-antigen increased the cloning efficiency of the serum-dependent cell line in soft-agar more than 50-fold, but cloning efficiency of serum-independent lines was not increased. Trypsinization of serum-independent lines required 100 times lower concentrations of trypsin than serum-dependent cells. Human metal-inducible T-antigen-producing (HMT) melanoma cells supported replication of transfected plasmids containing an SV40 origin of replication. Transient expression of interferon or plasminogen activator from such plasmids was 40-fold higher than in untransformed melanoma cells and could be enhanced 30-fold more by stimulation of transcription of the T antigen gene with cadmium chloride. HMT cells can be grown in suspension and thus may represent an attractive alternative to monkey kidney COS cells.
 ...
PMID:Transformation of Bowes melanoma cells with SV40 T antigen. 136 20

B cells derived from peripheral-blood lymphocytes (PBL) and tumor-infiltrating lymphocytes (TIL) from a patient with a high serum antibody titer to autologous melanoma were transformed with Epstein-Barr virus (EBV) and evaluated for reactivity against autologous tumor. B cells producing antibody reactive with autologous tumor and unreactive with normal fibroblasts were detected both in TIL and in PBL. One cell line derived from PBL and another derived from TIL sustained production of tumor-reactive antibody for 10 weeks and over 15 months respectively. The cell line derived from PBL, 2D11, produced an antibody reactive with a trypsin-resistant antigen expressed on the cell membrane of autologous and allogeneic melanoma cell lines. The cell line derived from TIL, 1F6, produced an antibody reactive with a cell-surface glycoprotein expressed by 5 autologous melanoma cell lines derived from 5 different metastases and 16/19 allogeneic melanoma cell lines. 1F6 also showed reactivity with cell lines derived from a blue nevus, a congenital nevus, an astrocytoma, and 1/4 renal-cell carcinomas; but it was not reactive with 5 foreskin melanocyte cell lines, 2 normal fibroblast lines, 5 leukemia/lymphoma lines, 8 lung-cancer lines, 8 glioblastoma lines, or lines derived from 1 ovarian carcinoma, 1 colon carcinoma, 1 vulvar carcinoma, 1 fibrosarcoma, 1 murine melanoma, or 4 murine leukemia/lymphomas. We describe here an antibody that detects a new melanoma specificity obtained by EBV transformation of tumor-infiltrating B cells.
 ...
PMID:Analysis of two human monoclonal antibodies against melanoma. 145 38

We recently reported the purification of a lymphocyte granule protein called "fragmentin," which was identified as a serine protease with the ability to induce oligonucleosomal DNA fragmentation and apoptosis (Shi, L., R. P. Kraut, R. Aebersold, and A. H. Greenberg. 1992. J. Exp. Med. 175:553). We have now purified two additional proteases with fragmentin activity from lymphocyte granules. The three proteases are of two types; one has the unusual ability to cleave a tripeptide thiobenzyl ester substrate after aspartic acid, similar to murine cytotoxic cell protease I/granzyme B, while two are tryptase-like, preferentially hydrolyzing after arginine, and bear some homology to human T cell granule tryptases, granzyme 3, and Hanukah factor/granzyme A. Using tripeptide chloromethyl ketones, the pattern of inhibition of DNA fragmentation corresponded to the inhibition of peptide hydrolysis. The Asp-ase fragmentin was blocked by aspartic acid-containing tripeptide chloromethyl ketones, while the tryptase fragmentins were inhibited by arginine-containing chloromethyl ketones. The two tryptase fragmentins were slow acting and were partly suppressed by blocking proteins synthesis with cycloheximide in the YAC-1 target cell. In contrast, the Asp-ase fragmentin was fast acting and produced DNA damage in the absence of protein synthesis. Using a panel of unrelated target cells of lymphoma, thymoma, and melanoma origin, distinct patterns of sensitivity to the three fragmentins were observed. Thus, these three granule proteases make up a family of fragmentins that activate DNA fragmentation and apoptosis by acting on unique substrates in different target cells.
 ...
PMID:Purification of three cytotoxic lymphocyte granule serine proteases that induce apoptosis through distinct substrate and target cell interactions. 146 Apr 16

In spite of the central role of tyrosinase in mammalian pigmentation, few data are available on its structure and structure-function relationships based on direct analysis of the protein. A number of reasons have been invoked to account for this situation, including the problems for its purification and its resistance to proteases. However, no study on the effects of proteases on purified tyrosinase has been reported. We have purified the melanosomal and cytosolic tyrosinases from B16 mouse melanoma and analyzed their susceptibility to trypsin digestion. Both isoforms are sensitive to trypsin, and display similar peptide maps and kinetics of proteolysis, suggesting that they are products of the same gene. The peptide maps and the kinetics of appearance of the fragments were consistent with the sequential removal of N-terminal peptides, leading to a core of 55.3 kDa for the melanosomal form and 48.6 kDa for the cytosolic enzyme. This core was apparently resistant to further proteolysis and catalytically inactive. The difference in molecular weight for the core of the cytosolic and melanosomal forms is the same as that calculated for the native isoforms. The kinetics of enzyme inactivation indicate that the tyrosine hydroxylase and Dopa oxidase activities of tyrosinase are lost at the same rate, and should therefore display similar if not identical structural requirements. The results are discussed in terms of the relationship of both isoforms and of the putative protein sequences deduced from the cDNA clones proposed for tyrosinase.
 ...
PMID:Proteolysis with trypsin of mammalian tyrosinase isoforms from B16 mouse melanoma. 149 41

Previous work conducted by the authors, using a murine model, suggested that soluble factors secreted by tumor cells suppress lymphocyte responses. To apply this premise to human tumors, the effects of UC729-6 (lymphoblastoid B-cell) and M21-HPB (malignant melanoma) conditioned media (CM) on normal lymphocyte proliferation, as well as on tumor cell growth in autologous CM was studied. The CM was collected at 2-5 day intervals from cultures of UC729-6 and M21-HPB cells in serum-free media. Phytohemagglutinin- and concanavalin A-stimulated mononuclear peripheral blood cells from healthy human donors showed decreased [3H]thymidine ([3H]Tdr) uptake in the presence of each CM when compared with controls. In assays using 100% CM, mitogen stimulation was 68-85% less than that of controls and 40-50% less using 50% CM. The suppression was more pronounced with UC729-6 CM than with M21-HPB CM. In mixed lymphocyte cultures (MLC), addition of 50% CM from either tumor cell line resulted in 40-50% reduction in [3H]Tdr uptake by lymphocytes. Incubation of UC729-6 cells in 5% to 100% of UC729-6 fCM (filter-concentrated) produced a decrease in [3H]Tdr uptake which was directly proportional to the amount of fCM present. In contrast, M21-HPB cell growth in autologous fCM was dependent on cell number, as well as on the amount of fCM used. Treatment of the UC729-6 fCM using acid (pH 4.5), trypsin (100 micrograms/ml), and heat (56 degrees C) did not restore mitogen-stimulated lymphoproliferation. However, the inhibition observed with UC729-6 fCM was partially reversed after dialysis with membranes having M(r) limits of 2.5 x 10(4), 1.5 x 10(4), or 1 x 10(4).
 ...
PMID:Immunosuppression derived from human B-lymphoblastoid and melanoma cell lines. 153 13


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>