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)

Different results have been reported on the expression of epidermal growth factor receptor (EGFR) in human melanocytic lesions, which may be due to different methodologic approaches. Therefore, we compared EGFR expression in six human melanoma cell lines by utilizing the monoclonal antibodies 2E9, 425, and 225, applying four immunocytochemical staining procedures. The results were compared with those obtained by a multiple point ligand binding assay. In addition, Northern blot analysis was performed. A three-step immunoperoxidase method using the monoclonal antibody 2E9 proved most sensitive. Staining intensities, estimated semiquantitatively, correlated well with the quantitative data obtained by the ligand-binding assay. Expression on the mRNA level was also in agreement with these results. Immunohistochemical staining of a large series of human cutaneous melanocytic lesions using the method selected showed differential EGFR expression in various stages of melanocytic tumor progression: 19% of common nevocellular nevi; 61% of dysplastic nevi, 89% of primary cutaneous melanomas, and 91% of melanoma metastases showed staining of the melanocytic cells. Intralesional heterogeneity of EGFR expression was present. Although the mean percentage of positive melanocytic cells in positive lesions did not increase with progression, mean staining intensity was stronger in malignant lesions compared to benign lesions. Ligand binding assays showed that EGFR expression in the highly metastasizing cell lines MV3 and BLM was at least 40 times higher than in the cell lines IF6, 530, M14, and Mel57, which do not or only sporadically metastasize after subcutaneous inoculation in nude mice. Although the differences between the various stages of progression are not absolute, we provide further evidence that EGFR expression increases in human melanocytic tumor progression.
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PMID:Increasing epidermal growth factor receptor expression in human melanocytic tumor progression. 162 28

We have examined the distribution of radiolabeled liposomes in tumor-bearing mice after i.v. injection. Two mouse tumors (B16 melanoma, J6456 lymphoma) and a human tumor (LS174T colon carcinoma) inoculated i.m., s.c., or in the hind footpad were used in these studies. When various liposome compositions with a mean vesicle diameter of approximately 100 nm were compared using a radiolabel of gallium-67-deferoxamine, optimal tumor localization was obtained with liposomes containing a phosphatidylcholine of high phase-transition temperature and a small molar fraction of monosialoganglioside or hydrogenated phosphatidylinositol (HPI). At 24 h after injection, average values of tumor uptake higher than 10% of the injected dose per g and liver-to-tumor ratios close to 1 were reproducibly obtained. Increasing the molar fraction of HPI from 9% to 41% of the total phospholipid resulted in enhancement of liver uptake and decrease of tumor uptake. Methodological aspects that influence vesicle size appear to affect significantly liposome localization in the tumor. However, varying the phospholipid dose within a 10-fold range caused only minor changes in the percent of injected dose recovered in the tumor. A high uptake by tumors was also observed using other radiolabels [[3H]inulin and indium-111-labeled bleomycin (111In-Bleo)] in monosialoganglioside- and HPI-containing liposomes. In the case of 111In-Bleo, encapsulation in liposomes resulted in approximately 20- to 40-fold increase in tumor accumulation of the radiolabel at 24 h after injection. The marked localization of liposomes in the mouse footpad inoculated with tumor as opposed to the contralateral mock-injected footpad was also documented by imaging experiments with gallium-67-deferoxamine and 111In-Bleo-labeled liposomes. These results support the contention that some glycolipid-containing liposomes previously shown to have long circulating half-lives accumulate significantly in a variety of tumors and are promising tools for the delivery of anti-tumor agents.
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PMID:Effect of liposome composition and other factors on the targeting of liposomes to experimental tumors: biodistribution and imaging studies. 169 20

The ability of cultured human fibroblasts to reorganize and contract three dimensional collagen I gels is regarded as an in vitro model for the reorganization of connective tissue during wound healing. We investigated whether adhesion receptors of the integrin family are involved. It was found that synthesis and transcription of the alpha 2 beta 1 integrin (but not of alpha 1 beta 1 or alpha 3 beta 1) is selectively upregulated when fibroblasts are seeded into type I collagen gels. Time course experiments revealed that high synthetic levels of alpha 2 beta 1 parallel the gel contraction process and return to "baseline" levels after the contraction has subsided. Furthermore, function-blocking mAbs directed to the alpha 2 and beta 1 chain of integrins inhibited gel contraction. Remodelling of connective tissue can be important for tumor cells during invasion and formation of metastases. Therefore, we tested human melanoma cell lines for this function. Five out of nine melanoma lines contracted collagen gels in vitro. Among these, two highly aggressive melanoma cell lines (MV3 and BLM) most efficiently contracted gels almost reaching the rate of normal adult fibroblasts. In these cells, synthesis of alpha 2 beta 1 was also significantly upregulated when seeded into collagen I gels. Moreover, function blocking anti-alpha 2 in conjunction with anti-beta 1 chain mAbs completely inhibited gel contraction for several days. Other melanoma cells (530) with lower metastatic potential which were not able to contract gels, showed no induction of alpha 2 beta 1 synthesis in gel culture. Our results suggest an important role of integrin alpha 2 beta 1 in the contraction of collagen I by normal diploid fibroblasts during wound healing and in the reorganization of collagen matrices by highly aggressive human melanoma cells.
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PMID:Integrin alpha 2 beta 1 is upregulated in fibroblasts and highly aggressive melanoma cells in three-dimensional collagen lattices and mediates the reorganization of collagen I fibrils. 195 83

In order to study differences in antigen expression related to the different stages of the process of metastasis of human melanoma cell lines, we determined the expression pattern of a series of well-characterized genes in a set of human melanoma cell lines with different metastatic behavior in nude mice. This set included non-metastatic (IF6, 530), sporadically metastatic (M14, Mel 57), and frequently metastatic (BLM, MV3) cell lines after subcutaneous inoculation. To study the phenotype of these cell lines both the cultured cells and representative samples of local tumors at the inoculation site and their metastases in the lungs were immunostained with a panel of monoclonal antibodies directed against melanocytic differentiation or progression antigens. Although most cell lines (IF6, 530, M14 and Mel 57) showed HLA-DR expression in vitro, these antigens were lacking in all xenografted lesions studied with exception of the 530 cell line. 530 Xenografts, however, showed a dramatic down-regulation of HLA-DR compared with the cell line in vitro. The same phenomenon was seen with respect to ICAM-1 expression. The expression of all other antigens studied in xenografts, both in subcutaneous tumors and in lung lesions, was in general comparable to that in the melanoma cell lines in vitro, with exception of the 530 cell line. In all melanoma cell lines except 530 the degree of intra- and interlesional heterogeneity regarding the expression of all antigens studied was limited. Remarkably, comparison of the immunophenotype of the frequently metastasizing (BLM, MV3) and the sporadically (M14, Mel 57) or non-metastasizing (IF6, 530) cell lines showed that the two frequently metastasizing cell lines had marked expression of the progression antigens VLA-2 and epidermal growth factor receptor, and lack of expression of the differentiation antigen NKI-beteb. These findings warrant further studies on the role of these antigens in the process of metastasis of human melanoma cells in nude mice.
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PMID:Antigen expression of metastasizing and non-metastasizing human melanoma cells xenografted into nude mice. 206 Jan 84

Several types of human cultured tumor cells were tested for the sensitivity to BLM, an effective antitumor antibiotic for epidermoid (squamous cell) carcinomas. Three cell lines (HeLa, KB, Hepd) derived from epidermoid carcinomas were very sensitive to BLM under concentrations tested, whereas BLM-resistant HeLa cells (HeLa-BLMr), neoplastic cells derived from salivary glands (HPA, HSG), malignant fibrous histiocytoma (MFH) and melanoma (MEC) were much less sensitive to BLM than epidermoid carcinoma cell lines under the same conditions. To investigate the possible mechanism of BLM resistance, these cell lines, namely HeLa, HeLa-BLMr, HSG and MEC, were examined for i) BLM permeability into cells by using 3H-PEP which was a new derivative of BLM, ii) BLM-inactivating activity in cell extracts by bioassay for antibacterial activity with B. subtilis PCI 219 strain, and iii) DNA repair activity after UV irradiation. Consequently, as compared with BLM-sensitive HeLa cells, BLM less sensitive HeLa-BLMr, HSG and MEC cells showed 34%, 50% and 39% reduction per 10(6) cells in BLM permeability, 1.6-, 5.6- and 4.7-fold increase per mg protein in BLM inactivating activity, and 24.5-, one and 8-fold enhancement in DNA repair activity, respectively. Therefore, it was indicated that above three factors at least were involved in the BLM sensitivity of human tumor cells.
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PMID:[Sensitivity to bleomycin of human cultured tumor cells and analysis of related factors]. 619 72

The glycoproteins recognized by monoclonal antibody (MAb) NKI-beteb are among the best diagnostic markers for human melanoma. MAb NKI-beteb reacts with melanoma cells throughout tumor development and does not cross-react with other tumor or normal cells, except for cells of the melanocytic lineage. Two other melanocyte lineage-specific MAbs, HMB-50 and HMB-45, show a specificity and staining pattern strikingly similar to the ones observed for NKI-beteb. Herein, we demonstrate that all three MAbs recognize protein products encoded by a single cDNA. Expression of this cDNA in BLM cells results in immunoreactivity with all three MAbs. In addition, we demonstrate co-distribution of the RNA species detected by the cDNA with the proteins recognized by the MAbs in tissue sections.
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PMID:Melanocyte lineage-specific antigens recognized by monoclonal antibodies NKI-beteb, HMB-50, and HMB-45 are encoded by a single cDNA. 750 84

By comparing two subsequent human tumor stages we previously described calcyclin as a new potential melanoma associated neoplastic progression marker positively linked with metastasis. In this study the calcyclin expression levels in a representative panel of human melanoma cell lines were correlated with the occurrence of DNase I hypersensitive (DH) regions and potential enhancer elements in a 6 kb genomic fragment spanning the human calcyclin gene. Examination of the chromatin structure of the transcription unit revealed no qualitative differences in DH sites within the panel of tested human melanoma cells, but especially the sequences around the transcription start site and a 1.5 kb upstream region appeared more accessible to the nuclease in frequently (BLM, MV3) as compared to poorly (530, 1F6) metastasizing cells. The genomic fragments that harbor one or more DH sites were subjected to functional analysis by luciferase reporter gene assays. Thus, an enhancer element was detected between 361 and 167 bp upstream of the transcription start site. This enhancer displayed equal activating potential (2-3 fold) both in weakly and in frequently metastasizing cells and was apparently recognized by transcription factors present in both types of human melanoma cells lines. We conclude that, in addition to a slight amplification of the encoding gene, the elevated calcyclin mRNA levels are only reflected in a selectively increased accessibility of the chromatin structure to DNaseI in metastasizing melanoma cells.
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PMID:Functional analysis of the human calcyclin gene promoter in a panel of human melanoma cell lines. 765 29

From a subtractive cDNA library, we isolated several cDNA clones which showed differential expression between highly and lowly metastatic human melanoma cell lines. One clone, designated nmb, showed preferential expression in the low-metastatic cell lines and was chosen for further characterization. Sequence analysis revealed that this clone represents a novel gene, encoding a putative transmembrane glycoprotein which showed the highest homology to the precursor of pMEL17, a melanocyte-specific protein. nmb RNA expression was absent in most tumor-cell lines tested and not restricted to the melanocytic lineage. Transfection of a partial nmb cDNA into a highly metastatic melanoma cell line (BLM) resulted, in 2 of 3 transfectants, in slower subcutaneous tumor growth and, in 1 of 3 transfectants, in reduction of the potential for spontaneous metastasis in nude mice.
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PMID:nmb, a novel gene, is expressed in low-metastatic human melanoma cell lines and xenografts. 781 55

In this study the relationship between tissue-type transglutaminase (TGase2) activity and the propensity to metastasize was investigated in human melanoma cell lines with different metastatic behavior. TGase2 catalyzes an acyl-transfer reaction between peptide-bound glutamine residues and primary amines, including the epsilon-amino group of lysine residues. Northern-blot analysis demonstrated that TGase2 RNA-expression (3.7 kb) was elevated in highly metastatic cell lines (MV3 and BLM) as compared to weakly metastatic ones (IF6 and 530). Immunoprecipitation and enzyme assays of TGase2 showed that the differential expression at the mRNA level was also reflected at the protein level. These findings reveal a positive relation between the expression of TGase2 and the metastatic properties of the human melanoma cell lines.
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PMID:Expression of tissue-type transglutaminase correlates positively with metastatic properties of human melanoma cell lines. 782 48

We recently isolated a cDNA clone that encodes the melanocyte lineage-specific antigen glycoprotein (gp)100. Antibodies directed against gp100 are an important tool in the diagnosis of human melanoma. Since the gp100 antigen is highly expressed in melanocytic cells, we investigated whether this antigen might serve as a target for antimelanoma cytotoxic T lymphocytes (CTL). Here, we demonstrate that cytotoxic tumor-infiltrating lymphocytes (TIL) derived from a melanoma patient (TIL 1200) are directed against gp100. HLA-A2.1+ melanoma cells are lysed by TIL from this patient. In addition, murine double transfectants, expressing both HLA-A2.1 and gp100, are lysed by TIL 1200, whereas transfectants expressing only HLA-A2.1 are not susceptible to lysis. Furthermore, the HLA-A2.1+ melanoma cell line BLM, which lacks gp100 expression and is resistant to lysis, becomes susceptible after transfection of gp100 cDNA. Finally, HLA-A2.1+ normal melanocytes are lysed by TIL 1200. These data demonstrate that the melanocyte differentiation antigen gp100 can be recognized in the context of HLA-A2.1 by CTL from a melanoma patient. Gp100 may therefore constitute a useful target for specific immunotherapy against melanoma, provided that no unacceptable cytotoxicity towards normal tissue is observed.
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PMID:Melanocyte lineage-specific antigen gp100 is recognized by melanoma-derived tumor-infiltrating lymphocytes. 811 68


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