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Query: UMLS:C0017638 (glioma)
 30,880 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Five primary and 3 established human glioma cell lines were cultured with ascorbate and examined for expression of extracellular matrix components. All lines except C6 expressed collagen as assessed by silver impregnation, immunofluorescence and lectin staining and expressed laminin and fibronectin. None expressed a lectin marker for endothelial cells. Both epithelial and mesenchymal collagens were expressed. While extracellular components of glioma lines resembled those of fibroblasts more closely than other cell types, subtle differences between gliomas and fibroblasts were present. These included more laminin and collagen type-IV antigenic reactivity and more 11-12 nm diameter extracellular fibrils from individual gliomas, and slight differences in spectra of low-molecular-weight extracellular proteins assessed by gel electrophoresis. One primary and two established glioma lines analysed for DNA content were aneuploid in contrast to diploid fibroblasts. Simultaneous expression of mesenchymal and epithelial markers suggests a dual differentiation potential of glioma cells. Results do not support an endothelial origin for cells cultured from gliomas.
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PMID:Products of cells cultured from gliomas. IV. Extracellular matrix proteins of gliomas. 351 74

In view of the hypothesis that a biochemical abnormality in the childhood forms of neuronal ceroid-lipofuscinosis may lie in the utilization of dolichols in glycoprotein synthesis, we analyzed the oligosaccharide structures of brain glycoproteins in infantile neuronal ceroid-lipofuscinosis (INCL). Lectin affinity chromatography of purified glycopeptides and of oligosaccharides prepared by hydrazinolysis showed an increase in high mannose-type glycopeptides and a decrease in tri- and tetra-antennary glycopeptides in INCL brain when compared with control brain. These changes were more pronounced in the storage cytosomes than in whole brain. Methylation analysis of the isolated glycopeptide fractions did not reveal differences in substitution patterns of the individual sugar residues between INCL and control brain. In INCL the core disaccharide of the O-glycosidically-linked oligosaccharides was sialylated to a higher degree than in control brain indicating that the structural changes were not confined only to N-glycosidically-linked carbohydrate chains. The observed structural changes in the carbohydrate chains of brain glycopeptides in INCL could be explained by a defect in the biosynthesis of glycoproteins. Alternatively, the changes may reflect the increased glial cell population in the degenerating brain. In fact, the elution profiles in lectin chromatography of oligosaccharides prepared from cultured rat glioma cells resembled those from INCL brain.
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PMID:Enrichment of high mannose-type glycans in nervous tissue glycoproteins in neuronal ceroid-lipofuscinosis. 395 Jun 50

The effects of mitogenic lectins Phytohemagglutinin (PHA), and Concanavalin A (Con A) on the growth rate of cells derived from glial tumors (astrocytoma, ependymoma, glioblastoma, medulloblastoma, and C6 rat glioma), neural crest tumors (neuroblastoma and schwannoma), and meningiomas were studied. The cell lines were of human and animal origin. The specificity of lectin binding to mitogenic receptors was evaluated using complementary monosaccharides. In all glial- and some neural-crest tumor-derived cell lines, there was a lectin concentration-dependent and cell density-dependent, biphasic growth rate response with stimulation at low and inhibition at high lectin concentrations. This response did not depend on the type of glial tumor, species of origin, or passage level in vitro. Although, in meningioma-derived cell lines, lectins did not induce a growth rate response, they caused morphological changes ("whorling"). Lectin stimulation in glial tumor-derived cell lines resembles that occurring in peripheral blood lymphocytes. Lectin-induced mitogenesis may lay the groundwork for the establishment of a model of glial cell proliferation, and that permits the evaluation of cell surface effects, intracellular mechanisms, and epigenetic factors in studies of tumors, neural development, and neuroimmunology.
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PMID:Mitogenic lectin receptors of nervous system tumors. Study of gliomas, neural crest tumors, and meningiomas in vitro using phytohemagglutinin and concanavalin A. 628 95

C6 glioma cells, and primary cultures of mouse astrocytes, stimulated with lipopolysaccharide (LPS) release an interleukin-1 like factor (IL-1) which enhances lectin-induced T-lymphocyte proliferation and promotes the release of interleukin-2 (IL-2) by ConA-stimulated thymocytes. In the present study, the glia maturation factor (GMF) was found not only to induce differentiation of glioblasts, but also to elicit the secretion of IL-1 like factors by cultured mouse astrocytes and their precursor cells. GMF was also effective in triggering IL-1 release by macrophages. Contamination of the 23 000 MW GMF preparation with LPS was excluded by the Limulus lysate assay and by using C3H/HeJ LPS-nonresponder mice whose glia and macrophages responded to GMF but not to LPS, by IL-1 release. Through its ability to induce glial differentiation and IL-1 release, GMF may represent an important endogenous signal, triggering both reactive gliosis and the development of an immune response within the central nervous system.
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PMID:Dual effect of glia maturation factor on astrocytes. Differentiation and release of interleukin-1 like factors. 660 46

Two normal and seven malignant human glia lines grown in vitro wer labelled by lactoperoxidase catalysed iodination. The labelled cell surface glycoproteins were isolated by lectin affinity chromatography and compared by SDS gel electrophoresis. The glia and the glioma lines possess a common characteristic glycoprotein pattern. Seven glycoproteins in the molecular weight range between 70,000 and 220,000 daltons and several minor components of low molecular weight could be distinguished. The expression of the glycoproteins was independent of the passage number or the growth conditions although the expression of the different glycoproteins showed quantitative differences for the individual cell lines. The differences found in the tumor lines were either due to an amplification or decrease in the expression of the different glycoproteins and/or their accessibility to the lactoperoxidase-catalysed labelling.
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PMID:Surface glycoproteins of normal and neoplastic glia cells in culture. 739 45

The activities of the sialyltransferase enzymes and the resulting expression of sialoglycoproteins were examined in tumor cells derived from different tissues in order to gain a greater understanding of the factors controlling the cell glycosylation state. Cell-cell contact, which is dependent on cell confluency state, was shown to influence glycosylation in the neurally-derived mouse neuro-2A neuroblastoma and the C6 glioma cell lines. Both showed a relatively high level of cell sialyltransferase activity under sub-confluent conditions with activity decreasing upon the formation of cell-cell contacts associated with confluency. A parallel decrease in the expression of sialoglycoproteins, as determined by lectin blot analysis, was observed under these conditions. In contrast, the H411e hepatoma cell line showed an increase in enzyme activity with confluency with the susceptibility of the enzyme in this cell line to glucocorticoid induction only being detected in sub-confluent cell cultures. The number of trypsinisation cycles of the cells was also shown to affect the enzyme activity of the neuro-2A and C6 cells with an increase in enzyme activity coincident with passage number being observed in the neuro-2A cells, and a decrease in the C6 glioma cell line. Trypsinisation had no effect on enzyme activity in the H411e cells. These results demonstrate that the control of sialyltransferase activity in tumor cells is multifactorial with the tissue of origin playing a key role.
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PMID:The control of sialyltransferase activity in tumor-cell lines derived from different tissues in multifactorial. 764 68

The lectin pathway is a novel pathway for activation of the complement cascade, which is initiated by the binding of mannose-binding protein (MBP) to its carbohydrate ligands. We investigated whether the complement system was activated in vitro by glioma cells through this pathway to the C3 level. MBP was found to bind to all six glioma cell lines tested by using flow cytometric analysis. Binding of a complex of MBP-associated serine protease and MBP was observed in two of the cell lines examined, thereby resulting in C4 consumption. Activation of C3 was hemolytically evaluated in these two lines. C3 consumption was also observed in one. Based on these results, it is likely that recognition by MBP followed by complement activation occurs in certain glioma cell lines.
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PMID:Mannose-binding protein recognizes glioma cells: in vitro analysis of complement activation on glioma cells via the lectin pathway. 773 Jan 43

To determine the N-linked oligosaccharide structure of beta-amyloid precursor protein (beta APP), soluble derivative of beta APP (APPs) was purified from the conditioned medium of beta APP cDNA-transfected C6 glioma cells. Two types of APPs with different molecular weight (larger APPs, L-APPs; smaller APPs, S-APPs) were obtained. The antibody against the N-terminal half of amyloid beta-protein showed no immunoreactivity with S-APPs, suggesting extensive truncation at the carboxyl terminus. From lectin blot analysis, the main structure of the N-linked oligosaccharide shared by L- and S-APPs was deduced to be of bi- or triantennary complex type with a fucosylated trimannosyl core and a bisecting GlcNAc residue. Additionally L-APPs was deduced to have Gal beta 1-->4GlcNAc, Fuc alpha 1-->2Gal beta and Sia alpha 2-->6Gal beta structures on its outer chains. However, lectins which recognize Fuc alpha 1-->2Gal beta and Sia alpha 2-->6Gal beta structures showed no reactivity with S-APPs. The present results suggest that the processing of beta APP may be regulated via the heterogeneity in the fine structure of its sugar chains.
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PMID:N-linked oligosaccharide of beta-amyloid precursor protein (beta APP) of C6 glioma cells: putative regulatory role in beta APP processing. 776 44

The expression of CMP-NeuAc: Gal beta 1,4GlcNAc alpha 2,6 sialyltransferase (alpha 2,6-ST) [EC 2.4.99.1] and glycoproteins bearing alpha 2,6-linked sialic acids were examined in primary human brain tumours and cell lines. 79% (19/24) of the meningiomas expressed alpha 2,6-ST mRNA, 42% (10/24) of which showed very high expression. alpha 2,6-ST mRNA expression was undetectable in normal brain tissue. In contrast, only 1/13 of the gliomas examined expressed detectable alpha 2,6-ST mRNA. Metastases to the brain did not express measurable amounts of alpha 2,6-ST mRNA. Less expression was found in malignant (i.e. anaplastic) compared to benign (i.e. meningothelial) meningiomas. Two-dimensional SDS-PAGE of glioma and meningioma proteins, followed by Sambucus nigra lectin staining, revealed the presence of a glycoprotein bearing alpha 2,6-linked sialic acids, M(r) = 53 kDa and a pI = 7.0 (MEN-1) that appeared in all seven of the meningiomas examined, but was expressed at barely detectable levels, if at all, in seven out of the seven glioblastomas examined. Thus, decreased alpha 2,6-ST expression may play a role in the aggressive nature of anaplastic meningiomas, but appears to be virtually absent in all tumours of glial origin.
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PMID:The expression of CMP-NeuAc: Gal beta 1,4GlcNAc alpha 2,6 sialyltransferase [EC 2.4.99.1] and glycoproteins bearing alpha 2,6-linked sialic acids in human brain tumours. 874 63

When treated with retinoic acid in vivo, C6 glioma cells show an enhancement of CMP-Neu5Ac:Gal beta 1-3 GalNAc-R alpha-2,3 sialyltransferase activity. A 300 kDa glycoprotein was detected by lectin affinoblotting in retinoic acid-treated C6 cells which stained weakly or not at all in control cells. Comparative studies with different lectins demonstrated that this glycoprotein contains alpha 2,3 Neu5Ac Gal-GalNAc O-glycan moieties. Cultures in the presence of an inhibitor of O-glycan synthesis (N-acetylgalactosaminide alpha-O-benzyl) demonstrated that enhancement of staining of the 300 kDa glycoprotein was not due to the increase of the alpha 2,3 sialytransferase but to the de novo synthesis of the polypeptide chain of this glycoprotein.
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PMID:Study of O-sialylation of glycoproteins in C6 glioma cells treated with retinoic acid. 878 91


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