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)

Coelectrophoresis in two-dimensional gels of rat glial fibrillary acidic protein (GFA) and 32P-labeled whole cell extracts of rat C-6 glioma cells showed that the GFA migrated in close proximity to a previously noted phosphoprotein, 50K-6.1, of these cells. GFA electrophoresed as a 50K polypeptide with at least four charge variants, the most acidic of which coelectrophoresed with 50K-6.1. Exposure of the C-6 cultures to dibutyryl cyclic AMP (dbcAMP) for 48 h increased the relative abundance of the endogenous polypeptide associated with 50K-6.1 by threefold, consistent with the hypothesis that 50K-6.1 was GFA. Norepinephrine stimulated 50K-6.1 phosphorylation 3.2-fold in dbcAMP-induced cultures. Peptide mapping with V8 protease and subtilisin was used to test the hypothesis that GFA and 50K-6.1 were identical polypeptides. With V8 protease, the peptides generated from the [35S]methionine labeled putative GFA spot of the C-6 cells were indistinguishable from the stained bands derived from authentic GFA in mixed samples of the two proteins. Likewise, the 35S-labeled acidic satellite to the putative GFA spot also yielded a peptide map that matched that of the authentic GFA. 32P-labeled peptides derived from the 50K-6.1 protein were a subset of those from authentic GFA. With three subtilisin concentrations, 32P-labeled 50K-6.1 was degraded to peptides which were again a subset of the stained GFA peptides. A cytoskeletal fraction from 32P-labeled C-6 cells contained a 50K phosphoprotein.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Glial fibrillary acidic protein: norepinephrine stimulated phosphorylation in intact C-6 glioma cells. 669 99

Human neuroblastoma SK-N-SH-SY5Y (5Y) and rat glioma (C6) cells were cultured with supplemental methionine, glycine, or serine for three to six days. Serine hydroxmethyltransferase (SHMT: L-serine: tetrahydrofolate 5, 10-hydroxymethyltransferase, EC 2.12.1) was assayed radiometrically in whole cell homogenates, crude supernatant fractions and crude particulate fractions. No significant changes in specific activity or cellular morphology were noted at methionine, glycine, or serine concentrations up to 16 mM. Serine concentrations of 20 and 40 mM led to significantly lower gliomal enzyme specific activities. This activity was unevenly distributed between soluble and particulate fractions, with 190 and 398 nmoles of HCHO formed per mg of protein per hour, respectively. Growth stage and time of incubation were major determinants of enzyme specific activity. C6 cells' specific activity rose slowly with increasing time in culture until cellular confluence. At this time there was a pronounced elevation in specific activity, occurring more rapidly in cells grown in 1.2 mM methionine. Intracellular amino acid analysis of C6 cells demonstrated a significant rise in methionine after four days in media containing 0.2 mM methionine. No appreciable diminution in the intracellular levels of glycine or serine occurred following incubation in excess methionine. It is concluded that SHMT-specific activity in C6 and 5Y cells is not regulated by glycine, serine, or methionine levels and that high concentrations of these amino acids (> 30 mM) are not detrimental to these cells derived from the CNS.
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PMID:Effect of methionine, glycine and serine on serine hydroxymethyltransferase activity in rat glioma and human neuroblastoma cells. 677 88

Messenger RNA (mRNA) extracted from a continuous human glioma cell line grown in culture or as a solid tumor was translated in an mRNA-dependent reticulocyte lysate system. Translation products labeled with [35S]methionine were immunoprecipitated with antiserum specific for glial fibrillary acidic (GFA) protein, separated by one- and two-dimensional polyacrylamide gel electrophoresis and analyzed fluorographically. Immunoprecipitates from both cell culture and tumor mRNA translations had a molecular weight of 49,000 daltons, consistent with GFA protein extracted from human tissue. In two dimensions, the 49,000-dalton band resolved into two to three spots at pH 5.7-5.9, the isoelectric point of GFA protein. Minor lower molecular weight products were detected in fluorographs of heavily overloaded gels or in film exposed for extended periods of time. These data indicate that the GFA protein produced by this glioma cell line is chemically and immunologically similar to normal human GFA protein, which suggests that the primary phenotypic expression of GFA protein in this tumor cell line is not altered by the neoplastic process.
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PMID:Glial fibrillary acidic protein synthesized in vitro using messenger RNA from a human glioma cell line. 682 46

Partially purified extracts from neuroblastoma x glioma hybrid cells inhibit via opioid receptors the PGE1-elicited formation of cyclic AMP in the same hybrid cell system. The purification of extracts reveals two active fractions very similar to Met- and Leu-enkephalin by several criteria including treatment with cyanogen bromide. On an average, the intracellular concentration of opioids in hybrid cells is 0.1 pmol per mg protein. The concentration is strongly dependent on the cell density. Furthermore, the content in the hybrids of enkephalin-like peptides is specifically elevated by glucocorticoids.
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PMID:Production and regulation of enkephalin-like peptides in neuroblastoma x glioma cells. 712

13C n.m.r. and thin-layer chromatography were used to monitor the degradation of methionine-enkephalinamide in the presence of neuroblastoma x glioma hybrid cells (NG 108-15) and membranes. Puromycin and trypsin treatment failed to protect enkephalinamide from degradation over long periods of time (up to 24 hours). The major degradation products of [3[2-13C]glycine] methionine-enkephalinamide observed by 13 C n.m.r. showed glycine-3 in a non-terminal position, an N-terminal position and free glycine. A minor component showed glycine-3 in a C-terminal position.
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PMID:Degradation of enkephalin and enkephalinamide by neuroblastoma x glioma hybrid cells as studied by 13C n.m.r. 721 24

A 3.5-kilobase cDNA encoding the dopamine transporter was isolated from a human substantia nigra cDNA library. Sequence analysis of the coding region of the transporter identified two nucleotide differences between the cDNA and published human dopamine transporter sequences. One of the substitutions changed an amino acid conserved among previously cloned dopamine (DA) and norepinephrine transporters, Arg-344, to a methionine. C6 glioma cells or COS-7 cells transfected with the cDNA (C6-hDAT and Cos7-hDAT cells) accumulated [3H]DA with high affinity (Km = 1.2 and 1.5 microM, respectively), and DA uptake inhibitors had similar potencies in both cell lines. [3H]2 beta-carbomethoxy-3 beta-(4-fluorophenyl)tropane ([3H]CFT) bound to membranes prepared from both cell lines with high affinity (Kd = 2-6 nM), although some experiments with C6-hDAT cell membranes indicated the presence of a second class of binding sites with lower affinity for the radioligand. Using the high-affinity Kd value for [3H]CFT binding determined in Cos7-hDAT cells to calculate Ki values, drug affinity for inhibition was highly correlated (r = .92) with affinity for inhibition of [3H]DA uptake, although transporter substrates were significantly more potent inhibitors of uptake than of [3H]CFT binding. The binding of [3H]1-[2-diphenylmethoxy]ethyl-4-(3-phenylpropyl)-piperazine ([3H]GBR-12935) to C6-hDAT cells could not be characterized due to high binding to untransfected C6 cells, but on Cos7-hDAT cells the radioligand labeled a single population of binding sites (Kd = 1 nM). Inhibition of [3H]GBR-12935 binding by drugs correlated highly with inhibition of either [3H]CFT binding (r = .98) or of [3H]DA uptake (r = .95).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Characterization of a recombinant human dopamine transporter in multiple cell lines. 761 9

We have previously shown that diet restriction-induced depletion of large neutral amino acids (LNAAs) in murine plasma to 46% of control significantly enhances intracranial delivery of melphalan without enhancing delivery to other organs. Studies have now been conducted to determine whether more substantial LNAA depletion could further enhance intracranial delivery of melphalan. Treatment with L-amino acid oxidase (LOX) significantly depleted murine plasma LNAAs: phenylalanine, leucine, and tyrosine (> 95%); methionine (83%); isoleucine (70%); and valine (46%). Experiments evaluating the intracellular uptake of melphalan and high-pressure liquid chromatography quantitation of melphalan metabolites revealed, however, that melphalan is rapidly degraded in the presence of LOX, and that the timing of the administration of melphalan following the use of LOX to deplete LNAAs is crucial. Conditions were found under which LOX-mediated degradation of melphalan was minimized and LNAA depletion was maximized, resulting in a potentiation of the antitumor effect of melphalan on human glioma xenografts in nude mice. Such potentiation could not be obtained using diet restriction alone.
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PMID:The effect of L-amino acid oxidase on activity of melphalan against an intracranial xenograft. 763 79

Positron emission tomography (PET) studies of a multicentric glioma case were undertaken using 11C-methionine (Met) and 18F-fluorodeoxyuridine (FUdR). Met-PET revealed high accumulating lesion in both the left and right hemispheres, whereas in the FUdR-PET, the lesion on the right showed marked accumulation, but not that on the left. For both foci, the histologic diagnoses were anaplastic astrocytoma, but the lesion on the right showed higher density of undifferentiated tumor cells than that on the left. PET studies using Met and FUdR are effective in delineating the proliferative potential of glioma cells, which otherwise cannot be determined by histopathologic studies.
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PMID:Multicentric glioma studied with positron emission tomography: a case report. 794 89

In vivo magnetic resonance spectroscopy (MRS) has revealed that phosphomonoesters (PME) such as phosphocholine (PCho) and phosphoethanolamine (PEth) are elevated in tumors and rapidly proliferating tissues. The regulation of PME levels and their relationship to proliferation are not well known. In the present study, we investigated the regulation of PCho and PEth levels in rat glioma cells grown in vivo and in vitro using 31P and 13C MRS. However, the ability of cells to produce choline endogenously is variable. To fully understand regulation of PCho levels, it is necessary to characterize the activity of the endogenous pathway, if it exists. This was first investigated by following the metabolic fate of 13C-labeled methionine of 9L glioma tumors in vivo. Our results indicate that there is a significant amount of de novo choline synthesis in vivo. However, similar experiments performed in vitro using cells cultured in bioreactors indicated that glioma cells themselves are unable to synthesize choline de novo, suggesting that the in vivo results were due to the involvement of extra-tumoral organs, e.g., liver. Further in vitro experiments demonstrated that the uptake and phosphorylation of physiologically relevant concentrations of exogenous choline is very active in these systems. Thus, it appears that the exogenous pathway for PCho biosynthesis predominates and regulates PCho levels in glioma cells. Our results also demonstrate that PCho levels are lowest, and PEth levels are highest, in non-proliferating cells. These observations indicate that there is a decrease in the biosynthesis of PCho concomitant with a reduction in culture growth. The source of the increased PEth is, as yet, undefined.
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PMID:In vitro and in vivo 13C and 31P NMR analyses of phosphocholine metabolism in rat glioma cells. 798 63

Amplifications of cellular oncogenes and growth factor genes have previously been reported in gliomas. Here we have evaluated 21 gliomas for amplification of tumor related genes including NMYC, EGFR, TGFalpha, MET, CMYC, SRC, HRAS, NRAS, SEC, ROS1, JUN, and WNT1. Five amplifications were observed. The epidermal growth factor receptor (EGFR) gene was amplified in 4 glioblastomas. The oncogene MET was amplified in a glioblastoma which showed no EGFR gene amplification. Importantly, both genes are located on chromosome 7 and belong to a family with tyrosine kinase activity. There was no amplification found for TGFalpha which was previously reported to be amplified in gliomas. The finding of MET and EGFR independently amplified in glioma lends further support to a crucial role of chromosome 7 in the development of gliomas.
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PMID:Two independent amplification events on chromosome 7 in glioma: amplification of the epidermal growth factor receptor gene and amplification of the oncogene MET. 801 63


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