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

Medroxyprogesterone, dexamethasone, or cortisone, locally applied in sustained release polymer to rabbit V2 carcinoma implanted in the rabbit cornea, blocked neovascularization and three-dimensional growth of the tumor. These hormones similarly prevented the vascular proliferative response to implants in the rabbit cornea of mouse B-16 melanoma and also the response to implants of polymer containing tumor extract with angiogenesis activity. The inhibitory responses were accompanied by considerable reduction in collagenolytic activity released into culture medium by explants of the two tumors and of the corneal region containing angiogenic hepatoma extract. Morphologic studies revealed extensive three-dimensional disruption of the compact laminated collagenous structure of the cornea by untreated V2 carcinoma. In the presence of hormone the tumor grew slowly as a noninvasive two-dimensional plaque limited to the narrow region of the insertion pocket in the cornea, with no obvious disturbance of structure elsewhere. Cortisone was much les effective than medroxyprogesterone or dexamethasone. Testosterone and estradiol had no effect on the three measured properties. The data suggest that local hormonal interference with neovascularization, collagenase production, and tumor growth can prevent neoplastic invasion and destruction of a dense collagenous connective tissue.
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PMID:Inhibition of tumor growth, vascularization, and collagenolysis in the rabbit cornea by medroxyprogesterone. 626 56

Extracellular matrix proteins synthesized and secreted by adherent human tumor cell lines were analyzed using metabolic labelling with glycine and proline in the presence of ascorbate, polypeptide analysis and polyacrylamide gel electrophoresis, affinity chromatography, collagenase digestion, and immunofluorescence staining. The results showed a characteristic pattern of matrix proteins for each tumor cell type. Tumor cell lines of mesenchymal origin produced mostly interstitial types (I and II) of collagen and fibronectin. Carcinoma cell lines secreted only basement membrane proteins, type IV collagen, laminin and fibronectin, but not interstitial collagen. A melanoma and a rhabdomyosarcoma cell line produced type V of procollagen that has not previously been described in cell culture. Neuroblastoma cells were shown to be phenotypically heterogeneous also with respect to matrix protein production. We propose that the analysis of extracellular matrix proteins may serve as an adjunct in the classification of human tumors.
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PMID:Extracellular matrix proteins characterize human tumor cell lines. 627 24

An aorta-derived inhibitor of endothelial cell and tumor cell growth and medroxyprogesterone, which depresses collagenase expression in vivo, were tested alone and in combination against B16-F10 melanoma in C57BL/6 mice in such doses that either agent alone had little effect. Together, these agents retarded growth of subcutaneously transplanted tumor cells and reduced the number and size of pulmonary tumors after iv tumor cell injection. Of the treatments used, only the aortic factor administered alone prolonged life in mice with pulmonary tumors.
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PMID:Effect of medroxyprogesterone and an aorta-derived cell growth inhibitor on B16 melanoma in mice. 632 11

Chromosome aberrations were analyzed in 4 cases of malignant melanoma (MM) after disaggregation of the tumors with collagenase and short-term culture. In all cell cultures, the MM cells displayed a typical triangular spindle form. The chromosome number was near-diploid in one case and near-triploid in three cases. A total of 27 abnormal chromosomes were identified with the Giemsa banding technique. By far, the most common types of abnormalities were translocations, followed by deletions and isochromosomes. Chromosomes 1, 6, and 7 were found to be most frequently involved in structural aberrations. Markers originating from chromosomes 1 and 6 were found in all four cases, and abnormalities of chromosome 7 were found in three. Each marker chromosome was unique for a given case; no common markers for two or more cases were found. Based on the present results and an analysis of reports on the chromosomal constitution of MM cells in the literature, we suggest that abnormalities involving chromosomes 6 and 7 may be a characteristic feature of MM. Aberrations of chromosome 1, although common in MM, may be part of a general cytogenetic feature in human neoplasia.
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PMID:Nonrandom chromosome changes in malignant melanoma. 688 47

As part of a programme to study the predictive clinical value of a soft agar assay for measuring chemosensitivity of human melanomas in vitro, we have observed the effect of three disaggregation methods on the yield of tumor cells, plating efficiency in soft agar and chemosensitivity. The yields and plating efficiencies obtained, as well as sensitivity to DTIC, CCNU, vinblastine and abrin, were about the same whether collagenase/pronase/DNase-treatment, trypsin/EDTA-treatment or mechanical treatment was used. When melanoma xenografts of different sizes were studied, an inverse relationship between tumor size and plating efficiency was found, whereas chemosensitivity was unaffected by tumor size. The highest plating efficiencies of melanoma cells, both from patient biopsies and from xenografts, were obtained when red blood cells were present and a low oxygen concentration (5%) was used. The results demonstrate that, in the case of melanomas, the fraction of tumor cells that are clonogenic in vitro depends on the size of the tumors, and even more so on the culture conditions used. An important finding was that chemosensitivity in vitro appears to be unaffected by the disaggregation method and by tumor size.
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PMID:Cultivation of human melanomas in soft agar. Factors influencing plating efficiency and chemosensitivity. 731 75

The degradation of tenascin purified from human melanoma cells was examined by treatment with matrix metalloproteinases (MMPs) and serine proteinases. Among eight different types of proteinases examined, MMP-1, -3, and -7, cathepsin G and leukocyte elastase could digest tenascin, but MMP-2, MMP-9 and thrombin did not. This suggests that tenascin may be readily catabolized by extracellular matrix-degrading proteinases found in the pathophysiological conditions.
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PMID:Susceptibility of tenascin to degradation by matrix metalloproteinases and serine proteinases. 752 86

Invasion of basement membranes is a key step in systemic spread of tumour cells. To analyze genetic mechanisms involved in this process, we have selected strongly and weakly invasive sublines with stable phenotypes from a primary human melanoma cell line by repeated passage through a reconstituted basement membrane in vitro. The sublines differed approximately 5-fold in their invasive potential. Invasiveness correlated with better attachment and overexpression of the integrin alpha v/beta 3 (vitronectin/laminin-receptor). Treatment with retinoic acid inhibited proliferation in both sublines and invasion in the weakly invasive cells but stimulated invasion in the strongly invasive subline. Northern-blot analyses revealed equal levels of mRNA expression regarding collagenase type-IV and retinoic-acid receptors but enhanced expression of TIMP-2 mRNA in weakly invasive cells. The 2 sublines differed significantly in their respective DNA ploidy when compared to the wild-type Mel Im cell line, suggesting that they represent heterogeneous clones present in the primary tumour. We have started to exploit this in vitro system for tumour heterogeneity to clone genes involved in invasion. By a subtractive cDNA cloning strategy, 12 partial cDNA clones were obtained that are specifically overexpressed in the strongly or weakly invasive subline. These results illustrate that stable genetic alterations lead to heterogeneous subpopulations within primary melanomas which differ in their ability to invade basement membranes and interact with components of the extracellular matrix.
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PMID:Characterization of selected strongly and weakly invasive sublines of a primary human melanoma cell line and isolation of subtractive cDNA clones. 753 59

We have previously shown that mouse sarcoma 180 cells produce vascular endothelial growth factor [VEGF; Rosenthal et al., 1990, Growth Factors, 4: 53-59], an endothelial mitogen that stimulates angiogenesis. Recent reports have implicated metalloproteinases and their inhibitors in the regulation of vascular morphogenesis, tumor invasion, and metastasis. We report here that mouse sarcoma 180 cells produce two collagenase inhibitors. These inhibitors were purified by heparin-Sepharose affinity chromatography, gel filtration, and C4 reverse phase h.p.l.c. Analytical gel electrophoresis of the purified inhibitors (MS-22 and MS-31) revealed molecular masses of 22,000 and 31,000 Da under reducing conditions, and 20,000 and 30,000 Da under nonreducing conditions, respectively. The NH2-terminal amino acid sequence of MS-22 was identical to that of tissue inhibitor of metalloproteinases type 2 (TIMP-2) produced by human melanoma cells [Stetler-Stevenson et al., 1989, J. Biol. Chem. 264: 17374-17378) over the first 30 amino acids. The NH2-terminal amino acid sequence of MS-31 was identical to that of murine TIMP-1 [Gewert et al., 1989, EMBO J 6:651-657]. Statistical analysis of the amino acid composition data of these two mouse sarcoma 180-derived collagenase inhibitors confirms the identification of MS-22 as TIMP-2 and MS-31 as TIMP-1.
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PMID:Purification and characterization of two collagenase inhibitors from mouse sarcoma 180 conditioned medium. 780 96

In this study, we examined the effect of expression of tissue inhibitor of metalloproteinases-2 (TIMP-2) on the growth and dissemination of a highly metastatic human melanoma cell line (M24net). M24net melanoma cells express a number of matrix metalloproteinases (MMPs), including gelatinase A and B (MMP-2 and MMP-9) and interstitial collagenase (MMP-1) (A. M. P. Montgomery et al., Cancer Res., 53: 693-700, 1993). The activity of these proteases was effectively down-regulated by transfecting M24net cells with complementary DNA-encoding human TIMP-2. Overexpression of TIMP-2 markedly reduced melanoma growth in the skin of immunodeficient mice but did not prevent these highly malignant cells from spontaneously metastasizing to the lungs and lymph nodes of inoculated mice. We provide a mechanism to account for the growth inhibitory property of TIMP-2 based on its ability to regulate M24net cell growth in three-dimensional interstitial collagen. In the presence of this matrix, M24net cells assume a differentiated morphology and have a reduced growth rate. We present evidence that overexpression of TIMP-2 increases the susceptibility of M24net cells to growth inhibition and morphological differentiation by occluding interstitial collagen.
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PMID:Effect of tissue inhibitor of the matrix metalloproteinases-2 expression on the growth and spontaneous metastasis of a human melanoma cell line. 792 81

A recently described personal method based on image analysis of histological sections was used in order to quantify lung colony formation by B16 melanoma cells injected intravenously into the mouse. These tumor cells were preincubated in vitro either with fibronectin (FN), laminin (LN) or fibroblasts (FB), which are implicated in the process of invasion and metastasis. Thanks to this method, a more accurate analysis of lung colonies (section area and number) formed by tumor cells was realized. By image analysis, we show that when FB were mixed with B16 cells, a drastic increase of tumor sections number and area was induced. LN increased the tumor sections area, but not their number. No effect of FN on B16 cells was observed. LN and FN promoted tumor anchorage in the depth of the lungs while FB reduced the latter. These facts could explain the contradictory results obtained by simply counting macroscopically superficial lung colonies. When cultured in vitro, these B16 melanoma cells did not produce any type of IV collagenase, either alone or in the presence of LN or FN, but in cocultures (B16 with 3T3) and in fibroblasts cultures, this enzyme was present. This could explain, among other factors, why the rate of invasiveness exerted by B16 cells is higher when the latter are coinjected with FB.
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PMID:Reevaluation by image analysis of the effects of fibroblasts, fibronectin or laminin upon colony formation in mouse lungs by B16 melanoma cells. 803 42


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