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)

Intracranial malignant gliomas are sequestered from the immune system yet are associated with broad suppression of host immunocompetence. Immune system dysfunction in patients with gliomas seems to be related to inhibitory mediators produced by glioma cells. We investigated the physiological roles of glioma-derived interleukin (IL)-10 in Class II expression of monocytes, cytokine secretion from lymphocytes, and T cell proliferation in vitro. We could detect the messenger ribonucleic acid transcript of IL-10 in four gliomas by the reverse-transcribed polymerase chain reaction. Glioma-derived IL-10 greatly down-regulated human lymphocyte antigens-DR expression on monocytes. The inhibitory effect of IL-10 on interferon-gamma and tumor necrosis factor-alpha was neutralized by the anti-IL-10 monoclonal antibody; however, the inhibitory effect on IL-2 was not neutralized. Next, supernatants of glioma cells remarkably suppressed T cell proliferation in a dose-dependent fashion; however, this inhibitory effect was not restored by adding anti-IL-10 monoclonal antibodies. The supernatant also inhibited the allocytolytic activity of lymphocytes that were not neutralized by anti-IL-10 monoclonal antibody. IL-10 plays an important role in cytokine synthesis; nevertheless, impaired T cell responsiveness cannot be solely explained by glioma-derived IL-10.
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PMID:Human glioma-derived interleukin-10 inhibits antitumor immune responses in vitro. 858 57

The presence and the possibility of induction of argininosuccinate synthetase in a glial cell line were investigated. For this purpose, antisera were produced against peptides representing partial sequences 196-222 and 337-349, respectively, of the mouse liver enzyme. Both antisera were shown to be monospecific for argininosuccinate synthetase. In Western blot experiments, immunoreactivity was found in mouse liver and brain homogenates. Only weak immunoreactivity was detectable in homogenates of cultured glioma cells, C6-BU-1. However, when the glioma cells were treated with either bacterial lipopolysaccharide, interferon-gamma, or a combination of both, argininosuccinate synthetase immunoreactivity was increased. The findings demonstrate that this enzyme is present in glial cells and is induced under conditions which stimulate persistent production of nitric oxide. The antisera will be a valuable tool for further investigations on arginine synthesis in brain as well as peripheral cells.
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PMID:Presence of argininosuccinate synthetase in glial cells as revealed by peptide-specific antisera. 904 64

Exposure to lipopolysaccharide (LPS) combined with phorbol-12-myristate-13-acetate (PMA) stimulates de novo synthesis of inducible nitric oxide synthase (NOS-2) in C6 glioma cells. Ethanol dose-dependently inhibits C6 cell NOS-2 activity, as measured by nitrite accumulation in culture medium, when present during LPS plus PMA treatment. The present study reports on mechanisms related to this inhibition. Ethanol added directly to cytosolic extracts did not inhibit NOS-2 catalytic activity, nor did ethanol decrease nitrite accumulation when added to cultures 24 hr after LPS plus PMA treatment. In contrast, NOS-2 enzymatic activity was significantly decreased in cytosolic extracts from cultures simultaneously exposed to ethanol and LPS plus PMA for 24 hr. Immunoblot analysis showed a coincident decrease in NOS-2 protein immunoreactivity. RNA analysis revealed that NOS-2 mRNA was decreased at both 12 and 24 hr during LPS plus PMA induction in the presence of ethanol. Subsequent experiments confirmed that 12-hr exposure to ethanol was sufficient to inhibit LPS/PMA-induced NOS-2 activity. Ethanol exposure also inhibited NOS-2 activity induced by LPS plus interferon-gamma, by LPS plus tumor necrosis factor-alpha and by tumor necrosis factor-alpha alone. These data point to an inhibitory ethanol effect at a site downstream from cytokine receptor activation and second messenger signal transduction mechanisms leading to suppression of NOS-2 gene expression in C6 cells.
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PMID:Suppression by ethanol of inducible nitric oxide synthase expression in C6 glioma cells. 910 44

Rat C6 glioma cells have been used to characterize molecular events involved in the regulation of inducible nitric oxide synthase (iNOS) gene expression stimulated by interferon-gamma (IFN-gamma) plus lipopolysaccharide (LPS). IFNs induce a signaling event which involves activation of Stat1 transcription factor. Previous studies have shown that IFNs also induce extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) activation. However, the mechanisms by which IFNs stimulate MAPK activation remain elusive. Here we show that in C6 glioma cells, transiently expressing the dominant-negative form of c-Ha-Ras (Asn-17) abrogated IFN-gamma-induced ERK1 and ERK2 activation. Furthermore, PD98059, a specific MEK1 inhibitor, also blocked this activation. These results indicate that p21ras and MEK1 are required for IFN-gamma-induced ERK1 and ERK2 activation. Recent studies have reported that MAPK is responsible for serine phosphorylation of Stat1 which is required for Stat1's DNA binding and maximal transcriptional activity. Thus, we examined the role of the Ras-MAPK pathway in Stat1 activation and subsequent iNOS induction in C6 glioma cells. Further experiments showed that neither Asn-17 Ras expression nor concentrations of PD98059, which completely abrogated IFN-gamma-induced ERK1 and ERK2 activation, affected Stat1 DNA binding activity or iNOS induction, indicating that the Ras-MAPK pathway does not appear to be involved in the activation of Stat1 and subsequent iNOS induction in C6 glioma cells.
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PMID:Activation of Stat1 and subsequent transcription of inducible nitric oxide synthase gene in C6 glioma cells is independent of interferon-gamma-induced MAPK activation that is mediated by p21ras. 918 Feb 63

The effect of transforming growth factor-beta (TGF-beta) secreted by glioblastoma (T98G) cells on the secretion of interferon-gamma (IFN-gamma) by lymphokine-activated killer (LAK) cells stimulated with tumor cells was investigated in cocultures of LAK and Daudi cells supplemented with T98G culture supernatant, T98G culture supernatant preincubated with anti-TGF-beta 1 and anti-TGF-beta 2 neutralizing antibodies, anti-TGF-beta 1 and anti-TGF-beta 2 antibodies, or natural human TGF-beta 1 or recombinant human TGF-beta 2. LAK cells were incubated with anti-TGF-beta 1 and anti-TGF-beta 2 antibodies, and with T98G cells of which the supernatant contained both active and latent forms of TGF-beta 1 and TGF-beta 2, with or without neutralizing antibodies. Addition of the supernatant from T98G cells to LAK/Daudi culture caused inhibition of IFN-gamma secretion by LAK cells. The inhibition was abolished by pretreatment of the supernatants with anti-TGF-beta antibodies. Addition of TGF-beta 1 and TGF-beta 2 to the LAK/Daudi culture inhibited IFN-gamma secretion by LAK cells in a dose-dependent manner. Addition of anti-TGF-beta antibodies to the LAK culture resulted in increased IFN-gamma secretion. T98G cells failed to stimulate LAK cells to secrete more IFN-gamma. Addition of anti-TGF-beta antibodies to the LAK-T98G culture resulted in increased IFN-gamma secretion by LAK cells. These results suggest that most malignant glioma cells which secrete high levels of TGF-beta can inhibit IFN-gamma secretion by LAK cells even after tumor cell stimulation.
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PMID:Transforming growth factor-beta inhibits interferon-gamma secretion by lymphokine-activated killer cells stimulated with tumor cells. 942 Apr 30

Considering the structural similarity between gabexate mesylate (FOY), a drug for serine proteinase-mediated diseases, and L-arginine, the effect of gabexate mesylate on the nitric oxide (NO) pathway has been investigated. Gabexate mesylate inhibits competitively constitutive and inducible NO synthase (cNOS and iNOS, respectively), with Ki values of 1.0 x 10(-4) M and 5.0 x 10(-3) M, respectively, at pH 7.4 and 37.0 degrees C. However, gabexate mesylate is not an NO precursor. Moreover, like other NOS inhibitors, gabexate mesylate increases iNOS mRNA expression in rat C6 glioma cells, as induced by E. coli lipopolysaccharide plus interferon-gamma. Finally, gabexate mesylate inhibits dose-dependently nitrite production (i.e. NO release) in rat C6 glioma cells, as induced by E. coli lipopolysaccharide plus interferon-gamma. Thus, this drug should be administered under careful control, since enzyme inhibition may occur also in vivo.
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PMID:Effect of gabexate mesylate (FOY), a drug for serine proteinase-mediated diseases, on the nitric oxide pathway. 961 Mar 82

1. Nitric oxide (NO) production in C6 glioma cells was directly monitored in real time by electrochemical detection with a NO-specific biosensor. 2. We present here the first direct evidence that noradrenaline elicits long-lasting NO production in C6 cells pretreated with lipopolysaccharide and interferon-gamma, an effect blocked by NG-monomethyl-L-arginine, a NO synthase inhibitor. 3. This direct electrochemical measurement of glia-derived NO should facilitate our understanding of the kinetics of glial signaling in glia-glia and glia-neuron networks in the brain.
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PMID:Direct and continuous electrochemical measurement of noradrenaline-induced nitric oxide production in C6 glioma cells. 961 1

The mechanisms underlying the antimanic effects of lithium are largely unknown but may involve long-term changes in brain gene expression. To determine if lithium could modify gene expression in astrocytes, the predominant cell type in brain, we tested the effects of LiCl on expression of nitric oxide synthase type 2 (NOS-2) in cultured glial cells. Incubation of primary rat astrocytes with endotoxin [lipopolysaccharide (LPS)] and proinflammatory cytokines induced NOS-2 gene and protein expression, as assessed by nitrite production and measurement of L-citrulline synthesis in whole cell lysates. Incubation with LiCl, but not KCl, increased NOS-2 activity up to 1.6-fold. LiCl also potentiated (up to 2.7-fold) the induction of NOS-2 expression by LPS plus interferon-gamma in C6 glioma cells but had little effect on LPS-induced nitrite accumulation from mouse RAW 264.7 macrophages. LiCl increased NOS-2 mRNA steady-state levels, suggesting an effect on mRNA stability and/or NOS-2 gene transcription. These results demonstrate that LiCl can modify astroglial gene expression and suggest that chronic treatment with lithium could exacerbate inflammatory responses in brain glial cells.
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PMID:Potentiation of astroglial nitric oxide synthase type-2 expression by lithium chloride. 968 82

In various systemic cancers, interleukin 12 (IL-12) induces anti-tumour immunity mediated by T lymphocytes and natural killer cells. To determine whether IL-12 has anti-tumour activity against malignant gliomas in the central nervous system (CNS), which is considered to be an immunologically privileged site, we treated mice with meningeal gliomatosis by intraperitoneal (i.p.) or intrathecal (i.t.) administration of recombinant murine IL-12. Although untreated mice revealed symptoms, such as body weight loss or paraplegia as a result of the meningeal gliomatosis within 8 days after tumour inoculation, 80% of the mice treated with IL-12 at 0.5 microg i.p. were cured. Many lymphocytes, mostly CD4+ and CD8+ cells, infiltrated to the tumours of IL-12-treated mice. The numbers of these cells increased in the cervical lymph nodes, into which the cerebrospinal fluid drains, and there they secreted a considerable amount of interferon-gamma. Mice cured by IL-12 rejected subcutaneous or i.t. rechallenge with their original glioma cells, but the same mice were not able to reject other syngeneic tumour cells. These results indicate that the immune system recognizes malignant glioma cells in the subarachnoid space of the CNS and that systemic IL-12 may produce effective anti-tumour activity and long-lasting tumour-specific immunity.
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PMID:Systemic interleukin 12 displays anti-tumour activity in the mouse central nervous system. 971 25

The effect of treatment with interleukin-1 beta (IL-1 beta), interferon-gamma (IFN-gamma), vincristine, and etoposide was evaluated on the secretion of transforming growth factor-beta (TGF-beta) and IL-10 and the expression of major histocompatibility complex (MHC) class I, intercellular adhesion molecule-1 (ICAM-1), and CD80 molecules by malignant glioma cells. Five malignant glioma cell lines were treated with IL-1 beta, IFN-gamma, and/or anticancer agents (vincristine and etoposide). Combined treatment with IL-1 beta and IFN-gamma caused greater inhibition of TGF-beta secretion compared to treatment with IFN-gamma, and almost the same levels of inhibition as treatment with vincristine and etoposide. The greatest inhibition of TGF-beta secretion was achieved by treatment with all agents. Low levels of IL-10 secretion were determined in two out of five malignant glioma cell lines. This IL-10 secretion was inhibited by treatment with IL-1 beta, IFN-gamma, vincristine, and/or etoposide. Treatment with both cytokines and anticancer agents increased the expression of MHC class I and ICAM-1 in all tumor cell lines. The mean increase of expression of MHC class I was 50% and that of ICAM-1 was 12-fold. No tumor cell lines expressed CD80 molecules on the cell surface, and no treatment caused CD80 expression. These results suggest that TGF-beta and IL-10 secretion by malignant glioma cells can be suppressed by treatment with a combination of IL-1 beta, IFN-gamma, vincristine, and etoposide, and the treatment up-regulates MHC class I and ICAM-1 expression on tumor cells. These results have implications for immunotherapy and chemotherapy in patients with malignant tumors.
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PMID:Down-regulation of transforming growth factor-beta and interleukin-10 secretion from malignant glioma cells by cytokines and anticancer drugs. 982 Nov 8


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