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

The hormonal control of cyclic nucleotide phosphodiesterase (EC 3.1.4.17) activity has been studied by using as a model the isoproterenol stimulation of cyclic AMP phosphodiesterase activity in C6 glioma cells. A 2-fold increase in cyclic AMP phosphodiesterase specific activity was observed in homogenates of isoproterenol-treated cells relative to control. This increase reached a maximum 3 h after addition of isoproterenol, was selective for cyclic AMP hydrolysis, was reproduced by incubation with 8-Br cycl AMP but not with 8-Br cyclic GMP and was limited to the soluble enzyme activity. The presence of 0.1 mM EGTA did not alter the magnitude of the increase in phosphodiesterase activity. Moreover, the calmodulin content in the cell extracts was not changed after isoproterenol. DEAE-Sephacel chromatography of the 100000 X g supernatant resolved two peaks of phosphodiesterase activity. The first peak hydrolyzed both cyclic nucleotides and was activated by Ca2+ an purified calmodulin. The second peak was specific for cyclic AMP but it was Ca2+- and calmodulin-insensitive. Isoproterenol selectively increased the specific activity of the second peak. Kinetic analysis of the cyclic AMP hydrolysis by the induced enzyme revealed a non-linear Hofstee plot with apparent Km values of 2-5 microM. Cyclic GMP was not hydrolyzed by this enzyme in the absence or presence of calmodulin and failed to affect the kinetics of the hydrolysis of cyclic AMP. Gel filtration chromatography of the induced DEAE-Sephacel peak resolved a single peak of enzyme activity with an apparent molecular weight of 54000.
 ...
PMID:Regulation by a beta-adrenergic receptor of a Ca2+-independent adenosine 3',5'-(cyclic)monophosphate phosphodiesterase in C6 glioma cells. 626 87

The immunoregulatory effects of TCGF (T-cell growth factor) on the generation and growth of syngeneic murine malignant glioma (20-methylcholanthrene-induced 203-glioma)-specific killer T-cell were investigated in C57BL/6 adult mice in order to clarify the immunopotential usefulness for anti-tumor local adoptive immunotherapy against malignant brain tumor. TCGF was prepared and assayed. Briefly, 5 x 10(6) ml mouse spleen cells were cultured with 2 microgram/ml concanavalin A in RPMI-1640 medium supplemented with 2% fetal calf serum for 24 hours. Culture supernatants were concentrated by ammonium sulphate precipitation (55 to 80% saturation) and purified by gel filtration (Sephadex G-100, a molecular weight from 30 to 36,000 daltons) and ion exchange chromatography (DEAE-cellulose, elution with 0.15 M in NaCl at ph 7.4). The purified TCGF had no IFN activity. Assays for TCGF was performed for quantitative analysis using 203-glioma-specific killer T cell clone (G-CTLL), which was obtained by limiting dilution method (0.3 cells/well in 96 well microtiter plate) and maintained for over 6 months in the presence of TCGF. Titer (U/ml) of TCGF was defined as the quantity of TCGF required to obtain one-half of the maximal stimulation of G-CTLL proliferation assay. It was confirmed that the specific killer T-cell against 203-glioma was generated in mice after intracranial as well as subcutaneous inoculation of the tumor cells. The killer T-cell activity of spleen cells, however, began to be severely impaired 2 weeks after intracranial inoculation concurrently with the increased intracranial pressure due to developing the tumor growth. Sensitized lymphocytes obtained from intracranial and subcutaneous tumor-bearing mice were assessed for CTL (cytotoxic T-lymphocyte) activity in MLTC (mixed lymphocyte-tumor cell culture) for 18 hours by microcytotoxicity assay. The specific cytotoxicity against 203-glioma cells was enhanced when sensitized lymphocytes from intracranial and subcutaneous tumor-bearing mice were pre-cultured with optimal TCGF (20 U/ml) for over 5 days. After the treatment of sensitized lymphocytes with anti-Thy-1 monoclonal antibody and complement, however, the specific cytotoxicity of sensitized lymphocytes was eliminated almost completely. Therefore, it was thought that TCGF possesses immunoregulatory effects of enhancement of killer T-cell activity. On the contrary, TCGF had no influence on normal T lymphocytes and the growth of 203-glioma cells in vitro.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:[Effects of TCGF (T-cell growth factor) on experimental malignant glioma-specific killer T-cell]. 660 19

The effect of rat submaxillary extract on the growth of rat C6 glioma cells in serum-free culture has been examined. Extracts (10-15 microgram/ml) of submaxillary glands from both male and female rats markedly enhanced the growth of serum-deprived C6 cells and, in combination with insulin, transferrin, and NIH-LH (a source of fibroblast growth factor), were able to stimulate C6 cell growth to an extent comparable to that achieved with an optimal amount of fetal calf serum. The mitogenic activity of rat submaxillary extracts was found to be heat-labile, acid-stable, and partially inactivated by protease and 2-mercaptoethanol. Under our assay conditions, biologically active preparations of purified mouse submaxillary gland epidermal growth factor (EGF) or nerve growth factor (NGF) were not mitogenic for C6 cells, nor was the mitogenic activity of rat submaxillary extracts inhibited by antiserum to these mouse submaxillary gland growth factors. These results suggest that the active component(s) of rat submaxillary extracts is unrelated to either EGF or NGF. The growth-enhancing effect also appears unrelated to esteropeptidase activity present in these extracts since the mitogenic activity was unaffected by several protease inhibitors. Moreover, two purified mouse submaxillary gland arginylesteropeptidases, EGF-binding protein and gamma-subunit of 7 S NGF, were unable to elicit a comparable growth response even when added to cell culture medium at unreasonably high concentrations. The C6 cell mitogenic activity of crude submaxillary extracts could be separated into two biologically similar components by either gel filtration on Sephadex G-100, preparative isoelectric focusing in a pH gradient of 3-10, or adsorption to DEAE-cellulose followed by elution with a sodium chloride gradient. One of the active components was acidic in nature and had an apparent molecular weight of 40,000, while the other was near neutral in charge and possessed a molecular weight of approximately 20,000. The relationship between these two C6 cell mitogenic components and the rat submaxillary gland component responsible for stimulating Balb/c-3T3 cell growth in serum-free, factor supplemented medium (McClure et al., 1979, J. Cell Biol. 83:96a) is also discussed.
 ...
PMID:Factors in the rat submaxillary gland that stimulate growth of cultured glioma cells: identification and partial characterization. 697 45

We have shown that several human malignant glioma cell lines are stimulated by bacterial lipopolysaccharide (E. coli 0111:B4, 1 microgram/ml) to produce a high molecular weight (> 200 kD) growth activity for BALB 3T3, clone A31 cells. This glioma-derived growth factor (GDGF-2) acts like a 'competence' factor. Malignant glioma cell line D-54 MG constitutively produced GDGF-2, which we have partially characterized from serum-free conditioned culture medium. GDGF-2 is resistant to heat (100 degrees C, 5 min), acidic (pH 2, 2 hr) or reducing (0.5 M 2 ME, 30 min) conditions as well as exposure to RNases; however, it is sensitive to > 4 freeze-thaw cycles, alkaline (pH 11, 2 hr) conditions or pre-treatment with proteolytic enzymes. GDGF-2 had a pl of 6.8 determined by preparative isoelectric focusing, bound to DEAE, with elution at 35 and 185 mM NaCl and at 43% acetonitrile from a C4 reversed phase column. GDGF-2 activity was not neutralized by antibodies to TGF alpha, TGF beta, PDGF, VEGF or TNF alpha indicating that it is not immunochemically related to these growth factors. However GDGF-2 co-chromatographed on Superose 12 HPLC (250 x 9 mm; 5% isopropanol, 6 mM CHAPS in PBS) with a substance that suppressed growth of mink lung epithelial cells (Mv1Lu), but not BALB 3T3 cells, and could be neutralized by anti-TGF beta antibodies. GDGF-2 activity eluted from heparin columns in 0.6 M NaCl; thus, it is not a heparin binding growth factor. D-54 MG cell line produced alpha 2-macroglobulin (alpha 2M), which is known to bind TGF beta; however, immunoprecipitation of alpha 2M did not deplete TGF beta or GDGF-2 activity. Further, neither GDGF-2 or TGF beta can be dissociated into lower molecular weight active components by chromatography in high salt (2 M NaCl) or 2-ME (0.5 M). GDGF-2 may be a novel autocrine or paracrine mitogen, stimulating mitotic division or interfering with normal cell growth regulation.
 ...
PMID:Partial characterization of glioma-derived growth factor 2: a novel mitogenic activity from human cell line D-54 MG. 814 64

Two molecular species of glioma-derived motility factor (GMF), GMF-I and GMF-II, have been purified to homogeneity from the serum-free conditioned medium of a highly invasive human glioma cell line, T98G, by gelatin affinity chromatography and heparin affinity-, DEAE-, hydroxyapatite-, gel permeation- and sulfopropyl high performance liquid chromatography. GMF-I and GMF-II showed a single protein band on non-reducing SDS-polyacrylamide gel electrophoresis with a molecular mass of 145 kDa and 165 kDa, respectively. The physico-chemical characteristics of these two GMFs are similar with respect to amino acid composition. GMF-I and GMF-II both stimulated the migration of T98G cells in a concentration-dependent manner, and the activity of GMF-I was about 5 times as strong as that of GMF-II. Checkerboard analysis demonstrated that the GMFs had not only a chemotactic effect but also a chemokinetic effect on T98G cells. C6 glioma cells and T98G cells, both of which showed high invasiveness in an in vitro invasion assay with reconstituted basement membrane, Matrigel, migrated to the GMFs with great intensity, while A172 and 9L glioma cells and normal glial cells, all of which weakly infiltrated the Matrigel barrier, migrated to the GMFs with much less intensity. These results indicate that migratory response of glioma cells to the GMFs correlates well with invasiveness, suggesting an important role(s) of the GMFs in the process of glioma cell invasion.
 ...
PMID:Purification of motility factor (GMF) from human malignant glioma cells and its biological significance in tumor invasion. 839 Feb 44

Rat C6 glioma synthesizes a low basal level of interleukin-6 (IL-6). Stimulation with 10 micrograms/ml of lipopolysaccharide (LPS) and induction of differentiation with 1 mM N6,O2'-dibutyryl cyclic AMP (dbcAMP) for 48 h increased the secreted activity to 400 and 800 U/ml, respectively. An LPS stimulation of dbcAMP-differentiated cells strongly enhanced the secreted activity. Depending on the dbcAMP concentration, the cell number, and the stimulation time, the secreted IL-6 level increased up to 120,000 U/ml. After 48 h of costimulation with 10 micrograms/ml of LPS and 1 mM dbcAMP, northern blotting and immunoassay demonstrated an eightfold increase in IL-6 mRNA concentration and IL-6 immunoreactivity, whereas titration of the biological activity indicated a 100-fold increase in the secreted IL-6 activity. The enhanced secretion of IL-6 is correlated with the induction of differentiation. Chromatography on heparin-Sepharose and on DEAE-5PW separated the secreted activity into several fractions, indicating that they differ in heparin affinity and charge either by posttranslational modifications or by binding to a carrier protein. Each of the partially purified IL-6-like activities could be neutralized by an anti-murine IL-6 antibody. Our observations demonstrate that in vivo inflammatory signals can trigger astrocytes and their precursors to secrete substantially different levels of immunoregulatory cytokines depending on their degree of differentiation.
 ...
PMID:Lipopolysaccharide-enhanced expression of interleukin-6 in dibutyryl cyclic AMP-differentiated rat C6 glioma. 859 15

We analysed the glycolipid composition of glioma cells (N-370 FG cells), which are derived from a culture of transformed human fetal glial cells. The neutral and acidic glycolipid fractions were isolated by column chromatography on DEAE-Sephadex and analysed by high-performance thin-layer chromatography (HPTLC). The neutral glycolipid fraction contained 1.6 micrograms of lipid-bound glucose/galactose per mg protein and consisted of GlcCer (11.4% of total neutral glycolipids), GalCer (21.5%), LacCer (21.4%), Gb4 (21.1%), and three unknown neutral glycolipids (23%). These unknown glycolipids were characterized as Lewis(x) (fucosylneolactonorpentaosyl ceramide; Le(x)), difucosylneolactonorhexaosyl ceramide (dimeric Le(x)), and neolactonorhexaosyl ceramide (nLc6) by an HPTLC-overlay method for glycolipids using specific mouse anti-glycolipid antibodies against glycolipid and/or liquid-secondary ion (LSI) mass spectrometry. The ganglioside fraction contained 0.6 micrograms of lipid-bound sialic acid per mg protein with GD1a as the predominant ganglioside species (83% of the total gangliosides) and GM3, GM2, and GM1 as minor components. Trace amounts of sialyl-Le(x) and the complex type of sialyl-Le(x) derivatives were also present. Immunocytochemical studies revealed that GD1a and GalCer were primarily localized on the surface of cell bodies. Interestingly, Le(x) glycolipids and sialyl-Le(x) were localized not only on the cell bodies but also on short cell processes. Especially, sialyl-Le(x) glycolipid was located on the tip of fine cellular processes. The unique localization of the Le(x) glycolipids suggests that they may be involved in cellular differentiation and initiation of cellular growth in this cell line.
 ...
PMID:Expression and localization of Lewis(x) glycolipids and GD1a ganglioside in human glioma cells. 873 37

Purified bovine brain G-protein was used in a solution phase assay to identify membrane-associated proteins that influenced the activation of heterotrimeric G-proteins. Detergent-solubilized membrane extracts from the neuroblastoma-glioma cell hybrid NG108-15, but not the parent C6B4 glioma cell line, increased [35S]GTPgammaS binding to purified G-protein by approximately 460%. The G-protein activator was heat-sensitive, and the magnitude of its action was related to the amount of extract protein. The biophysical and biochemical properties of the G-protein activator were determined using DEAE ion exchange chromatography, gel filtration, and a lectin affinity matrix. In the presence of added GDP (1 microM), the enriched G-protein activator increased the initial rate of [35S]GTPgammaS binding to brain G-protein by up to 4-fold. In the absence of added GDP, the G-protein activator elicited an initial burst in [35S]GTPgammaS binding to brain G-protein within the first 30 s, after which the rate of nucleotide binding to G-protein was similar in the absence or presence of the G-protein activator. The stimulation of nucleotide binding to brain G-protein by the activator was also observed after resolution of Galpha from Gbetagamma. The G-protein activator was distinct from other proteins (neuromodulin, tubulin, and beta-amyloid precursor protein) that influence nucleotide binding to G-protein, indicating the existence of a novel signal accelerator.
 ...
PMID:Characterization of a G-protein activator in the neuroblastoma-glioma cell hybrid NG108-15. 893 52

Two-dimensional (2-D) DNA fingerprinting was used to investigate genomic changes in human low-grade gliomas of different subtypes. DNA variations were identified in the 2-D hybridization patterns as spot losses or gains. Computer-aided matching of spot patterns from different patients revealed a clustering of spot changes at particular areas in the gel. Representative spots of each cluster were cloned using a spot cloning protocol which includes the preparation of a duplicate and a master gel. The DNA fragments of the 2-D gels were transferred to DEAE and nylon membrane, respectively. After hybridization of the master blot with a minisatellite core probe, the position of a particular spot was determined with reference to the lambda DNA fragments used as external markers in both gels. The gel spot DNA was recovered from the DEAE membrane by high salt elution and was polymerase chain reaction (PCR)-amplified after ligation of adaptor oligo cassettes. The PCR products were cloned and used as locus-specific probe for the rehybridization of the 2-D blots. One of these probes detected a spot loss in 7 of 28 low-grade gliomas of different subtypes analyzed. Another probe revealed a characteristic intensity shift in 8 of 9 pilocytic astrocytomas between two neighboring spots. The target sequence of this highly specific effect was assigned to chromosome 11q14 by in situ hybridization of a P1 clone harboring the affected genomic region. Thus, we successfully established a spot cloning procedure for the generation of locus-specific probes that may be instrumental in the discovery of the critical early events of glioma pathogenesis.
 ...
PMID:Cloning of minisatellite-containing sequences from two-dimensional DNA fingerprinting gels reveals the identity of genomic alterations in low-grade gliomas of different patients. 937 26

The 45, 55, 65 and 100 kDa ATP-binding proteinases (ATP-BPases) of the heat-shocked (44 degrees C for 30 min, recovery for 12 h) rat C6 glioma cells were purified by DEAE-ionexchange and ATP-affinity chromatography. Their molecular masses, isoelectric points (pI), pH-optima and other properties were analyzed by native proteinase gels. It was shown that the 65 kDa ATP-BPase is specifically induced by heat shock and not detectable in control cells. Its N-terminal 1-9 amino acid sequence was determined by Edman degradation, but no homologies to other proteins in the protein data bases were found. 30 and 31 kDa proteinases can be cleaved from the 45, 55 and 65 kDa proteinases to which they are linked. A possible relationship of the heat-induced 65 kDa ATP-BPase with the ATP-dependent proteinases (ATP-DPases) in prokaryotes and eukaryotes is discussed.
 ...
PMID:Heat shock induction of a 65 kDa ATP-binding proteinase in rat C6 glioma cells. 1041 33


<< Previous 1 2 3 Next >>