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)

A distinguishing characteristic of cells of the melanocyte lineage is the expression of the melanosomal enzyme tyrosinase that catalyzes the synthesis of the pigment melanin. A tyrosinase cDNA clone, designated BBTY-1, was isolated from a library constructed from the pigmented TA99+/CF21+ melanoma cell line SK-MEL-19. Expression of BBTY-1 in mouse L929 fibroblasts led to synthesis and expression of active tyrosinase, and, unexpectedly, to stable production of melanin. Melanin was synthesized and stored within membrane-bound vesicles in the cytoplasm of transfected fibroblasts. BBTY-1 detected a 2.4-kb mRNA transcript in nine of nine pigmented, tyrosinase-positive melanoma cell lines. Tyrosinase transcripts of the same size and abundance were detected in a subset (three of eight) of nonpigmented, tyrosinase-negative melanoma cell lines, suggesting that post-transcriptional events are important in regulating tyrosinase activity. Two melanocyte antigens, recognized by mAbs TA99 and CF21, that are specifically located within melanosomes and are coexpressed with tyrosinase activity, did not react with transfected mouse fibroblasts expressing human tyrosinase, supporting the conclusion that these antigenic determinants are distinct from the tyrosinase molecule coded for by BBTY-1.
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PMID:Induction of pigmentation in mouse fibroblasts by expression of human tyrosinase cDNA. 249 55

Tumor necrosis factor (TNF-alpha) was compared to immune interferon (IFN-gamma) for its ability to modulate the expression and shedding of HLA antigens, of intercellular adhesion molecule I (ICAM I) and of high-molecular-weight melanoma-associated antigen (HMW MAA) by a panel of melanoma cell lines. The latter included the melanoma cell line MeWo and its metastatic variant MeM 50-10, which display differential susceptibility to modulation of HLA class-II antigens by IFN-gamma and the cell lines SK-MEL-93-DX-2 and SK-MEL-93-DX-3, which originated from anatomically distinct metastases in patient DX. TNF-alpha enhanced the expression of HLA class-I antigens on all 7 melanoma cell lines tested, although to a lower extent than IFN-gamma and the combination of IFN-gamma and TNF-alpha. TNF-alpha displayed a differential effect on the expression of HLA class-II antigens by the 7 melanoma cell lines: it enhanced it on 3 out of the 4 cell lines with constitutive expression of HLA class-II antigens and induced them on 1 of 3 cell lines without detectable expression of these antigens. The effects of IFN-gamma were different since it enhanced HLA class-II antigens on the 4 cell lines with constitutive expression of these antigens and induced them on 2 out of the remaining 3 lines. Interestingly, both TNF-alpha and IFN-gamma enhanced the expression of HLA class-II antigens by SK-MEL-93-DX-3 cells. On the other hand only TNF-alpha induced the expression of HLA class-II antigens by MeWo cells and only IFN-gamma induced such expression by MeM 50-10 cells and by SK-MEL-93-DX-2 cells. The effect of the combination of TNF-alpha and IFN-gamma was similar to that of the individual cytokines. Both TNF-alpha and IFN-gamma displayed a differential effect on the expression of the gene products of the HLA-D region by the melanoma cell lines. Northern blot analysis with HLA-DR beta-, DQ beta- and DP beta-specific probes suggests that the modulation of HLA class-II antigens by both cytokines reflects transcriptional and post-transcriptional events. TNF-alpha enhanced the expression of ICAM-I on all the melanoma cell lines, although to a lower extent than IFN-gamma and the combination of IFN-gamma and TNF-alpha. Lastly, neither TNF-alpha nor IFN-gamma displayed a marked effect on the expression of HMW-MAA by the melanoma cell lines tested.
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PMID:Differential modulation by tumor necrosis factor and immune interferon of HLA class-II antigens expressed by melanoma cells. 250 38

Mouse melanoma cells in culture respond to melanocyte-stimulating hormone (MSH) by demonstrating increased activity of tyrosinase, the rate-limiting enzyme for melanin synthesis. Because this stimulation is strictly dependent upon continued transcription and translation, we have carried out studies to determine if MSH increases the level of tyrosinase mRNA. The abundance of tyrosinase message levels in melanoma cells treated with either MSH or dibutyryl cAMP was determined by Northern blot analysis utilizing a 946 base pair mouse tyrosinase cDNA probe. The tyrosinase cDNA was isolated from a lambda gt11 expression library generated from mRNA isolated from theophylline-induced Cloudman melanoma cells. The abundance of tyrosinase mRNA was determined in an amelanotic cell clone (AM-7AS) and a melanotic cell clone (MEL-11AS). The melanotic cell line had five times as much tyrosinase activity and almost 10 times more tyrosinase mRNA than the amelanotic line. Tyrosinase activity and mRNA increased in both cell lines after MSH addition. The amelanotic line treated with MSH for three days showed a fivefold increase in tyrosinase activity and a twofold increase in tyrosinase mRNA. The melanotic cell line treated with MSH for three days showed a 3.7-fold increase in enzyme activity and an eightfold increase in the abundance of tyrosinase mRNA. Dibutyryl cAMP also stimulated tyrosinase activity and the accumulation of tyrosinase mRNA. The data suggest that MSH, acting through cAMP, promotes an accumulation of tyrosinase mRNA.
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PMID:Regulation of tyrosinase mRNA levels in mouse melanoma cell clones by melanocyte-stimulating hormone and cyclic AMP. 254 86

The effect of granulocyte-macrophage colony-stimulating factor (GM-CSF), a pluripotent cytokine, on tumoricidal activity of alveolar macrophages and monocytes from nonsmoking normal volunteers was compared using [3H]thymidine-labeled human tumor cells (SK-MEL-28, melanoma) as targets. A dose-response study (500-5000 units/ml) of recombinant GM-CSF indicated dramatic differences between cytotoxicity of alveolar macrophages and blood monocytes. Macrophages exhibited significant (P less than 0.01) tumoricidal activity at all GM-CSF doses tested. In contrast, monocytes showed no significant tumoricidal activity at 500 units/ml and significantly (P less than 0.01) less activity than alveolar macrophages at doses of 1000-5000 units/ml. Maximal activity in alveolar macrophages occurred 72-96 h after exposure to 1000-5000 units/ml GM-CSF. Tumoricidal activity may be related to the state of maturation, because monocytes matured in vitro for 7 days displayed enhanced tumoricidal activity after GM-CSF exposure. Tumor necrosis factor alpha and interleukin 1 beta were measured in supernatant fluids of 24-h GM-CSF-treated cells. No significant increase in either cytokine was detected after GM-CSF treatment of alveolar macrophages. Monocyte interleukin 1 beta secretion was not enhanced by GM-CSF; however, tumor necrosis factor alpha secretion was enhanced in some donors (three of five). Superoxide anion production of alveolar macrophages was not enhanced by GM-CSF. These data suggest that alveolar macrophage tumoricidal activity is induced by GM-CSF and is not dependent on oxidative metabolism or secreted forms of interleukin 1 beta or tumor necrosis factor alpha.
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PMID:Differential effect of recombinant granulocyte macrophage colony-stimulating factor on human monocytes and alveolar macrophages. 254 32

The human gene locus c-MEL was identified following transfection of genomic DNA from the human melanoma cell line NK14; it has previously been assigned to chromosome 19 (p13.2-q13.2) by analysis of somatic cell hybrids. We have further refined the position of this gene to the proximal region of 19p (cen-p13.2), using cell hybrids containing only fragments of human chromosome 19. We have confirmed this physical localisation by linkage analysis with a recently described restriction fragment length polymorphism for the c-MEL gene, and mapped the locus within the region of the low density lipoprotein receptor gene (LDLR) (Lod 4.43, theta = 0.10) and the anonymous marker D19S11 (13.1.25) (Lod 9.33, theta = 0). This gene thus maps to a region of chromosome 19 involved in karyotypic abnormalities in a variety of malignancies including melanomas and leukaemias.
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PMID:Confirmation and refinement of the localisation of the c-MEL locus on chromosome 19 by physical and genetic mapping. 256 40

A highly heterogeneous cell line, IIB-MEL-J, was established from a human metastatic melanoma. This cell line contains small cells, dendritic cells, and megacells with multiple nuclei. IIB-MEL-J expresses S 100, cytokeratin intermediate filaments and the gangliosides GD2 and GD3. It requires growth factors (insulin, EGF, and transferrin) and antioxidants for optimal growth. When plated under optimal conditions, IIB-MEL-J grows with a doubling time of 70-80 hours. The cells may be fractionated by Percoll gradient centrifugation into several subpopulations (A, B, and C) with different characteristics. Subpopulation A is the slowest growing, and most of the DNA-synthesizing cells are concentrated in fractions B and C. Every subpopulation expresses S 100 and cytokeratin intermediate filaments, whereas only subpopulation B and C express GD2 and GD3. Pigmented cells are concentrated mainly in subpopulation C. Cytogenetic analysis of IIB-MEL-J revealed extensive chromosomal alterations, including a highly heterogeneous chromosome number and chromosomal rearrangements, gains, losses, isochromosomes, and double minutes. This highly heterogeneous cell line may be helpful to study cellular differentiation and interaction between different subpopulations in human melanoma.
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PMID:Characterization of IIB-MEL-J: a new and highly heterogenous human melanoma cell line. 260 42

Seven monoclonal antibodies (mAbs) reactive with ganglioside II3(NeuAc)2-LacCer (GD3) were generated; four of these mAbs (DMAb-21, DMAb-22, DMAb-23, and DMAb-24) by immunizing mice with GD3 adsorbed to Salmonella minnesota and the remaining three (DMAb-7, DMAb-8, and DMAb-17) with melanoma line SK-MEL 28, which contains 1.4 nmol sialic acid of GD3 per mg protein. The specificities of the mAbs were defined by high-performance thin-layer chromatography (HPTLC) immunostain and solid-phase radioimmunoassay (SP-RIA) with a panel of purified gangliosides. DMAb-7 and DMAb-8 reacted with GD3, IV3(NeuAc)2nLcOse4Cer(3',8'-LD1), and very weakly with IV3(NeuAc)2II3NeuAcGgOse4Cer (GT1a), but not with II3NeuAc-LacCer (GM3), II3NeuAcGgOse3Cer(GM2), II3NeuAcGgOse4Cer (GM1), II3NeuAc, IV3NeuAcGgOse4Cer (GD1a), II3(NeuAc)2GgOse3(GD2), II3(NeuAc)2GgOse4Cer (GD1b), IV3NeuAcII3(NeuAc)2, GgOse4Cer(GT1b), suggesting the binding epitope to be a terminal tetrasaccharide NeuAc alpha 2-8NeuAc alpha 2-3Gal beta 1-4(Glc or GlcNAc). DMAb-7 and DMAb-8 were used to investigate the expression of GD3 on cultured human tumor cells of neuroectodermal origin. Thirteen of 19 gliomas, 3 of 5 medulloblastomas, 5 of 5 neuroblastomas, 2 of 2 melanomas, and 1 of 3 teratomas were shown to react with DMAb-8 and/or DMAb-7 by cell surface-RIA (CS-RIA) and immunofluorescence (IF) assays. HPTLC and densitometric analysis confirmed these results, as positive immunostains in the GD3 region were obtained with oligoganglioside fractions from 9 glioma, 1 medulloblastoma, 2 neuroblastoma, 1 melanoma, and 1 teratoma cell line. Glioma cell line U-105 MG and medulloblastoma cell line Daoy contain GD3 as shown by HPTLC immunostain analysis of extracts, although GD3 was undetectable on the cell surface as determined by CS-RIA and IF.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:GD3 expression by cultured human tumor cells of neuroectodermal origin. 260 39

Unambiguous 13C-nmr assignments for the widely used pesticide rotenone have been made through the judicious use of APT, CSCM 1D, and selective INEPT spectroscopy. Also, in order to more fully characterize the biologic potential of rotenone, studies were performed with cultured cells. Intense, but nonspecific, activity was observed in the P-388 lymphocytic leukemia, KB carcinoma of the nasopharynx, and a number of human cancer cell types: e.g., HT-1080 human fibrosarcoma, LU-1 lung cancer, COL-2 colon cancer, MEL-2 melanoma, and BC-1 breast cancer cell lines in vitro.
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PMID:13C-nmr spectral assignment and evaluation of the cytotoxic potential of rotenone. 261 25

The influence of immunologic parameters on the clinical course of malignant melanoma is increasingly evident. However, it is not known which factors contribute to the immunologic host reaction against malignant melanoma. Because epidermal cells and, in particular, normal as well as transformed keratinocytes recently have been demonstrated to release various immunomodulating cytokines, the capacity of melanoma cells to produce interleukin-1 (IL-1) was examined. Accordingly, supernatants derived from different melanoma cell lines contained significant levels of IL-1 activity. Upon high-performance liquid chromatography (HPLC) gel filtration, melanoma cell-derived IL-1 (MEL-IL-1) exhibited molecular weight heterogeneity, and HPLC chromatofocusing revealed major activity at pH 5.0 and minor activity at pH 7.0. A monoclonal antibody directed against monocyte-derived IL-1 blocked MEL-IL-1 activity significantly and was able to precipitate four species of biosynthetically radiolabeled MEL-IL-1 (25, 17, 6, and 4 kilodaltons), suggesting that MEL-IL-1 is identical to monocyte-derived IL-1. This was also confirmed by Northern blot analysis detecting IL-1 alpha specific mRNA in melanoma cells by hybridization with a cDNA fragment encoding for IL-1 alpha. Thus, melanoma cells, like other epidermal cells, exhibit the capacity to release the immunomodulating cytokine IL-1 and, therefore, probably have the potency to influence host defense mechanisms directed against malignant melanoma.
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PMID:Expression and release of interleukin-1 by different human melanoma cell lines. 278 56

Cytolytic T-lymphocyte (CTL) clones against an autologous melanoma (SK-MEL-29) were generated by mixed lymphocyte tumor culture and subsequent cloning of responder lymphocytes at limiting dilutions. These CTL clones lysed autologous melanoma but not autologous Epstein-Barr virus-transformed B cells and none of the allogeneic tumor targets included in the specificity analysis. The lysis of autologous melanoma targets could be inhibited by monoclonal antibodies against monomorphic HLA class I determinants. For proliferation of CTLs, the stimulation with the relevant target antigen on autologous tumor cells was essential. Immunoselection experiments carried out with two CTL clones revealed the existence of melanoma subclones that were resistant to lysis by the CTL clones used for immunoselection but were still lysed by other autologous CTL clones. This analysis allowed us to identify three stable simultaneously expressed antigens on the melanoma cells defined by autologous CTLs.
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PMID:Cytolytic T-cell clones against an autologous human melanoma: specificity study and definition of three antigens by immunoselection. 278 58


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