Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0017638 (glioma)
 30,880 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Several lines of evidence suggest that gangliosides may play a role in the regulation of growth in many cell types. Here we describe the effects on growth of two different cell lines by the addition of two different chemicals which have been reported to elevate the cellular ganglioside content through different mechanisms. Growth of neuroblastoma (Neuro 2a) cells in medium containing fetal bovine serum was inhibited in a dose-dependent fashion by both exogenous GM1 ganglioside and NeuAc2en, an inhibitor of sialidase activity. In contrast, growth of glioma cells (U-1242 MG) was not affected by exogenous GM1 or NeuAc2en in the presence of as little as 1% calf serum. However, NeuAc2en inhibited growth of U-1242 MG cells stimulated by platelet-derived growth factor in serum-free medium. These results demonstrate that the growth inhibitory effects of ganglioside on U-1242 MG but not Neuro 2a cells can be counteracted by serum, suggesting that the mechanisms through which gangliosides affect cell growth may be different for different growth factors and cell types.
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PMID:Effects of GM1 and 2-deoxy-2,3-dehydro-N-acetylneuraminic acid (NeuAc2en) on neuroblastoma (Neuro 2a) and human glioma cells (U1242 MG). 182 41

The ability of both primary astrocytes from rat cerebrum and a rat C6 glioma cell line to take up lysosomal enzymes by receptor-mediated endocytosis was compared. The beta-glucuronidase secreted by 3T3 fibroblasts was purified to homogeneity by antibody affinity chromatography, iodinated and used as a typical enzyme to determine the nature of receptors involved in its uptake into glial cells. Both primary astrocytes and C6 glioma cells took up 125I-labelled enzyme in a rapid and saturable manner indicative of specific receptors, while immunostaining with an anti-mouse beta-glucuronidase antibody showed that the enzyme was distributed in a mainly punctate pattern after uptake, characteristic of that of lysosomes. Subcellular fractionation of C6 glioma cells following endocytosis revealed that the enzyme became localised in lysosomes, after first passing through an endosomal compartment. Uptake of enzyme was reduced markedly after its sugar side chains had been removed with N-glycanase, indicating that endocytosis was mediated via a carbohydrate-recognising receptor. A range of carbohydrates and glycoproteins were tested for their ability to inhibit receptor-mediated endocytosis but of these only sialic acid had a notable effect. Further evidence that endocytosis of beta-glucuronidase into primary astrocytes and C6 gliomas may be mediated via sialic acid receptors was provided by the large reduction in rate of uptake observed following removal of this sugar from the enzyme with sialidase.
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PMID:Receptor-mediated uptake of beta-glucuronidase into primary astrocytes and C6 glioma cells from rat brain. 319 88