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

The differential adhesion of cultured mammalian clonal cell lines to components of the extracellular matrix was examined by kinetic adhesion and long-term growth assays. Uniform artificial matrices were prepared by air drying collagen Type I solution (C) onto a microtiter well and then air drying a solution containing a single glycosaminoglycan (GAG): hyaluronic acid (HA), chondroitin sulfate-4 (CHS-4), or chondroitin sulfate-6 (CHS-6). The adhesion of [3H]thymidine-prelabeled cells suspended in fibronectin (FN) depleted medium was measured at 2 and 6 hr. Neuroblastoma (N18, Lan 1) and melanoma (B16, G361, S91) cell lines exhibited a significantly greater percentage of cells adhering to one or more C-GAG matrices compared with C matrices. Maximal adhesion at 2 hr was to C-HA. In contrast at 2 hr, two glial, two epithelial, and one fibroblastic cell line showed unchanged or significantly decreased binding to C-GAG compared with C matrices. Further experiments using a neuroblastoma (N18) and a glioma (C6) cell line indicated that the adhesion patterns were not altered either by the method of dissociation from the tissue culture dish, preincubation with exogenous GAG, or the addition of exogenous fibronectin. Assays of N18 and C6 adhesion to matrices made from a non-GAG polyanionic compound, polygalacturonic acid (PGA), did not yield the same adhesion patterns as C-HA matrices. Long-term growth studies of a neuroblastoma (N18) melanoma (S91), and glioma (C6) cell line on nonuniform matrices deliberately prepared with GAG-rich and GAG-poor regions complemented the observations from the kinetic adhesion assays. N18 and S91 cells did not grow on areas which did not contain GAG by toluidine blue staining. However, the C6 cells did not grow on areas which did strongly stain for GAG. A quantitative analysis of the long term growth of N18 and C6 cells substantiated these observations. All these data indicate that the cellular phenotype may be correlated with matrix adhesion. Neuroblastomas and melanomas have a greater affinity for GAG-containing matrices while glial, epithelial, and fibroblastic cells appear to have a greater or equal affinity for collagen matrices.
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PMID:Correlation of the cell phenotype of cultured cell lines with their adhesion to components of the extracellular matrix. 640 96

Three types of murine tumors, B-16 melanoma, A-10 carcinoma, and S-180 sarcoma, were shown to contain elevated glycosaminoglycan (GAG) concentrations in vivo as compared to normal muscle or subcutaneous tissue. Hyaluronate was especially concentrated in the A-10 carcinoma, which contained approximately six times more hyaluronate than subcutaneous tissue and 18 times more than muscle. In all three tumors, chondroitin sulfates, especially chondroitin-4-sulfate, were present in higher concentrations than in the normal tissues. In culture, however, all three tumor cell lines produced less than 5% as much GAG as mouse fibroblasts, when measured by incorporation of [3H] acetate or by chemical analysis. Varying the culture passage number or the medium composition, ie, glucose, serum, and insulin concentrations, had little effect on GAG synthesis by the tumor cells. The low GAG levels in the tumor cell cultures were not due to hyaluronidase activity in their media. In an attempt to mimic possible host-tumor cell interactions that could account for the elevated GAG levels in vivo, tumor cells were cocultured with fibroblasts, but no stimulation above the amount made by the tumor cells alone plus that by the fibroblasts alone was observed. Conditioned media from the tumor cells, either dialyzed or not against fresh complete medium, had no effect on fibroblast GAG synthesis. Tumor extracts, however, were found to stimulate synthesis of hyaluronate by fibroblasts. Stimulation by extracts of A-10 carcinoma was greater than and additive to that of serum. The above results strongly suggest that GAG production in these tumors is in part regulated by host-tumor interactions.
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PMID:Stimulation of glycosaminoglycan production in murine tumors. 651 22

Heparan sulfate (HS), a prominent component of vascular endothelial basal lamina, is cleaved into large Mr fragments and solubilized from subendothelial basal lamina-like matrix by metastatic murine B16 melanoma cells. We have examined the degradation products of HS and other purified glycosaminoglycans produced by B16 cells. Glycosaminoglycans 3H-labeled at their reducing termini or metabolically labeled with [35S]sulfate were incubated with B16 cell extracts in the absence or presence of D-saccharic acid 1,4-lactone, a potent exo-beta-glucuronidase inhibitor, and glycosaminoglycan fragments were analyzed by high speed gel permeation chromatography. HS isolated from bovine lung, Engelbreth-Holm-Swarm sarcoma, and subendothelial matrix were degraded into fragments of characteristic Mr, in contrast to hyaluronic acid, chondroitin 6-sulfate, chondroitin 4-sulfate, dermatan sulfate, keratan sulfate, and heparin which were essentially undegraded. Heparin, but not other glycosaminoglycans, inhibited HS degradation. The time dependence of HS degradation into particular Mr fragments indicated that HS was cleaved at specific intrachain sites. In order to determine specific HS cleavage points, HS prereduced with NaBH4 was incubated with a B16 cell extract and HS fragments were separated. The newly formed reducing termini of HS fragments were then reduced with NaB[3H]4, and the fragments hydrolyzed to monosaccharides by trifluoroacetic acid treatment and nitrous acid deamination. Since 3H-reduced terminal monosaccharides from HS fragments were overwhelmingly (greater than 90%) L-gulonic acid, the HS-degrading enzyme responsible is an endoglucuronidase (heparanase).
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PMID:Metastatic melanoma cell heparanase. Characterization of heparan sulfate degradation fragments produced by B16 melanoma endoglucuronidase. 669 65

Glycosaminoglycans (GG) synthesized by two tumorigenic cell lines and a nontumorigenic, immunoprotective cell line derived from the B16 mouse melanoma were metabolically labeled with Na235SO4 and [3H]glucosamine. The radioactive GG synthesized at low and high cell densities were prepared from cells and culture media and analyzed by enzymatic and chromatographic methods. The cell-associated and medium GG from both low- and high-density cultures of the nontumorigenic, immunoprotective line contained a significantly higher proportion of heparin and heparan sulfate (85-95% of total) relative to comparable fractions from the tumorigenic lines. In addition to synthesizing less heparin and heparan sulfate and more chondroitin 4-sulfate plus chondroitin 6-sulfate, the tumorigenic lines differed in that the amelanotic line produced significant amounts of dermatan sulfate which remained cell associated. None of the lines produced measurable amounts of hyaluronic acid. In addition, the nontumorigenic immunoprotective line incorporated two to six times more precursor into total GG and released a higher proportion into the growth medium than did the tumorigenic lines.
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PMID:Glycosaminoglycans synthesized by tumorigenic and nontumorigenic mouse melanoma cells in culture. 693 79

The glycosaminoglycans produced by human fetal uveal melanocytes and by human melanoma cells were examined. The cells were grown in the presence of [3H]glucosamine and [35S]sulfate, and the labeled glycosaminoglycans were isolated from the cells, spend medium, and intracellular material. The distribution of the glycosaminoglycans was similar in both cells and spent media, which together accounted for 95% of the total. Of the total 3H]labeled glycosaminoglycans produced by the melanocyte culture, 42% was in chondroitin 4-sulfate, 25% in heparan sulfate, 16% in chondroitin 6-sulfate, and 17% in hyaluronic acid. In contrast, HM7 human melanoma cultures produced no chondroitin 6-sulfate, increased quantities of heparan sulfate, and less hyaluronic acid. A heparan sulfate fraction obtained from melanocytes required both heparitinase and heparinase for complete degradation, indicating the presence of heparin-like molecules in this fraction. The corresponding fraction from melanoma cells was totally degraded by heparitinase alone.
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PMID:Glycosaminoglycans of cultured human fetal uveal melanocytes and comparison with those produced by cultured human melanoma cells. 729 96

CD44 is a M(r) 90,000 surface glycoprotein believed to be involved in cell adhesion and migration. We investigated the role of CD44 in tumor growth and metastasis using human melanoma cell lines SMMU-1 and SMMU-2. Both SMMU-1 and SMMU-2 form tumors in the s.c. tissues when injected s.c. in SCID mice but only SMMU-2 metastasizes. Approximately one-half of SCID mice receiving injections of SMMU-2 s.c. develop metastatic tumors. SMMU-2 but not SMMU-1 expresses high levels of the hematopoietic form of CD44 and binds fluorescence-conjugated hyaluronic acid in vitro. GKW.A2 is a monoclonal antibody specific for human CD44 that can completely inhibit the binding of hyaluronic acid to SMMU-2 tumor cells in vitro. Moreover, in vivo injection of GKW.A3 inhibited the growth and metastatic potential of SMMU-2 tumor cells. Administration of GKW.A3 i.v. 1 week after s.c. tumor injection did not inhibit local tumor development but inhibited the formation of metastatic tumors and prolonged animal survival. Therefore, interactions between CD44 on tumor cells and its ligands in vivo may be necessary for tumor growth and metastasis.
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PMID:Inhibition of human melanoma growth and metastasis in vivo by anti-CD44 monoclonal antibody. 751 Oct 44

CD44 is implicated in the regulation of tumor growth and metastasis but the mechanism by which expression of different CD44 isoforms determines the rate of primary and secondary tumor growth remains unclear. In the present study we use a human melanoma transfected with wild-type and mutant forms of CD44 to determine which functional property of the CD44 molecule is critical in influencing tumor behavior. We show that expression of a wild-type CD44 isoform that binds hyaluronic acid augments the rapidity of tumor formation by melanoma cells in vivo, whereas expression of a CD44 mutant, which does not mediate cell attachment to hyaluronate, fails to do so. The importance of CD44-hyaluronate interaction in tumor development is underscored by the differential inhibitory effect of soluble wild-type and mutant CD44-Ig fusion proteins on melanoma growth in vivo. Whereas local administration of a mutant, nonhyaluronate binding, CD44-Ig fusion protein has no effect on subcutaneous melanoma growth in mice, infusion of wild-type CD44-Ig is shown to block tumor development. Taken together, these observations suggest that the tumor growth promoting property of CD44 is largely dependent on its ability to mediate cell attachment to hyaluronate.
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PMID:Interaction between CD44 and hyaluronate is directly implicated in the regulation of tumor development. 751 17

Changes in glycoconjugate production have been reported for tumor cells. In this study, we investigated the glycoconjugate expression pattern in normal human melanocytes and in a panel of 6 human melanoma cell lines with different metastatic capacity after s.c. inoculation into nude mice. Glycoconjugates were labeled in vitro with [35S] sulphate and [3H] glucosamine, purified from cells and culture medium by column chromatography and identified by treatment with specific glycosidases. Characterization of the purified glycoconjugate fractions as well as alcian-blue staining of xenograft lesions revealed that hyaluronic acid (HA) is the main glycoconjugate produced by all cell lines. Highly metastatic cell lines expressed higher levels of HA than melanocytes and than weakly metastatic or non-metastatic cell lines. In addition, a shift in dominance from chondroitin-sulphate proteoglycan to heparan-sulphate proteoglycan was observed with increasing metastatic capacity. We also studied the expression and binding activity of the HA receptor CD44. Immunoprecipitation experiments indicated high CD44 synthesis only in highly metastatic cell lines, but FACS analysis demonstrated approximately the same surface expression in melanocytes as in all cell lines. Adhesion assays to immobilized HA showed that CD44 can be present in an inactive or an active conformation. Our data suggest that a combination of increased HA production and the expression of CD44 on the cell surface may be associated with high metastatic potential of human melanoma cell lines in nude mice.
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PMID:Glycoconjugate profile and CD44 expression in human melanoma cell lines with different metastatic capacity. 753 56

Phenotypic and functional aspects of melanoma-hyaluronate interactions were investigated by studying the expression of CD44, cell migration, and transmembrane penetration of human melanoma cell lines on hyaluronate-coated substrates. Expression of CD44 was tested by flow cytometry on seven human melanoma cell lines. Strong reactivity with anti-CD44 monoclonal antibody was observed in four of seven of the cell lines. Migration studies of CD44(+) cell lines on hyaluronic acid- and chondroitin-6-sulfate-coated substrates, using time-lapse video-microscopy, showed a dramatic dose-dependent increase in migration rate on hyaluronate but not on chondroitin-6-sulfate. Moreover, CD44(-) cell lines showed no modification in migration rate on either substrate. Addition of soluble hyaluronate produced a dose-dependent inhibition of acceleration of CD44(+)cells on hyaluronate-coated substrates, whereas addition of chondroitin-6-sulfate had no effect. Migration inhibition experiments with soluble CD44 (CD44 receptor globulin) also showed specific blocking of the migration of CD44(+) cells on hyaluronate. Haptotactic invasion was increased in CD44(+) cell lines through hyaluronate-coated polycarbonate membranes, whereas no change was detected on chondroitin-6-sulfate-coated membranes. CD44(-) cell lines showed no response to either type of coating. In the melanoma cell lines tested, the expression of CD44 correlated with in vitro migration and invasiveness on hyaluronate substrates. Taken together, our data are consistent with the suggestion that CD44 may play a role in stimulating in vivo aggressiveness of tumors through hyaluronate-rich stroma.
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PMID:Migration of human melanoma cells on hyaluronate is related to CD44 expression. 842 33

CD44-mediated cell adhesion to hyaluronate is controlled by mechanisms which are poorly understood. In the present work we examine the role of N-linked glycosylation and Ser-Gly motifs in regulating CD44-hyaluronate interaction. Our results show that treatment of a panel of human cell lines which constitutively express CD44 with the inhibitor of N-linked glycosylation tunicamycin results in the loss of attachment of these cells to hyaluronate-coated substrate. In contrast, treatment of the same cells with deoxymannojirimycin, which inhibits the conversion of high mannose oligosaccharides to complex N-linked carbohydrates, results in either no change or an increase in CD44-mediated adhesion to hyaluronate, suggesting that complex N-linked oligosaccharides may not be required for and may even inhibit CD44-HA interaction. Using human melanoma cells stably transfected with CD44 N-linked glycosylation site-specific mutants, we show that integrity of five potential N-linked glycosylation sites within the hyaluronate recognition domain of CD44 is critical for hyaluronate binding. Mutation of any one of these potential N-linked glycosylation sites abrogates CD44-mediated melanoma cell attachment to hyaluronate-coated surfaces, suggesting that all five sites are necessary to maintain the HA-recognition domain in the appropriate conformation. We also demonstrate that mutation of serine residues which constitute the four Ser-Gly motifs in the membrane proximal domain, and provide potential sites for glycosaminoglycan side chain attachment, impairs hyaluronate binding. Taken together, these observations indicate that changes in glycosylation of CD44 can have profound effects on its interaction with hyaluronic acid and suggest that glycosylation may provide an important regulatory mechanism of CD44 function.
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PMID:Glycosylation of CD44 is implicated in CD44-mediated cell adhesion to hyaluronan. 860 95


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