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

Lysis of tumor cells by activated cytotoxic lymphocytes requires their recognition of antigens associated with major histocompatibility complex molecules. The authors studied the constitutive expression of Class I and Class II major histocompatibility complex antigens on mouse brain-tumor cells and the capacity of different cytokines and cytokine combinations to alter this expression in vitro. Cells from the murine glioma 26 (GL26), glioma 261 (GL261), and ependymoblastoma A (EpA) cell lines were established in monolayer culture and treated for 48 hours with either alpha interferon, gamma interferon, tumor necrosis factor alpha, tumor necrosis factor alpha plus gamma interferon, or interleukin-2. They were then analyzed by flow cytometry for baseline and cytokine-altered major histocompatibility complex expression. All cell lines had a similar constitutive major histocompatibility complex pattern with low Class I antigen expression and no detectable Class II antigen expression. Alpha interferon substantially induced and up-regulated Class I antigen expression, but had no effect on Class II antigen expression. Gamma interferon also stimulated up-regulation of Class I antigen expression, generally doubling the anti-Class I antigen fluorescence of treated cells. Its effect on Class II antigen expression was more extensive. In the GL26 and GL261 cell lines the expression of Class II antigen determinants increased to 12 x and 14 x control values and as many as 75% of cells that had no detectable constitutive expression of Class II antigen expressed this antigen after priming with gamma interferon. The addition of tumor necrosis factor alpha to gamma interferon further increased Class II antigen expression on EpA tumor cells only. Interleukin-2 and tumor necrosis factor alpha alone had no effect on Class I or Class II antigen expression of any cell lines. It is concluded that Class I and Class II antigen expression in mouse glioma cell lines is induced and enhanced after treatment with certain cytokines in vitro. Use of these cell lines to create in situ primary brain tumors in C57BL/6 mice should provide an excellent animal system to study major histocompatibility complex modulation in brain tumor cells and to examine the potential impact of major histocompatibility complex up-regulation on the response of brain tumors to immunotherapy.
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PMID:Expression and modulation of major histocompatibility antigens on murine primary brain tumor in vitro. 158 18

Human malignant glioma cell lines and clones were incubated with various concentrations of recombinant human TNF-alpha, either alone or in combination with recombinant human IFN-gamma. The surface expression of HLA-ABC (class I) antigens and beta 2-microglobulin, was significantly enhanced by TNF-alpha alone on every cell line and clone tested. After incubation with both TNF-alpha and IFN-gamma, the surface expression of HLA-ABC antigens was only slightly higher than that observed with each cytokine alone. In contrast to IFN-gamma, TNF-alpha had no effect on the surface expression of HLA-DR (class II) antigens. Moreover, the surface expression of HLA-DR induced by IFN-gamma was unaffected by TNF-alpha. The increased expression of HLA-ABC antigens after treatment with TNF-alpha or IFN-gamma correlated with increased levels of HLA-ABC-specific mRNA. In addition, TNF-alpha, like IFN-gamma, selectively enhanced the surface expression of a tumor-associated antigen, Me14-D12, while it had no effect on the expression of various other surface antigens. In the absence of actinomycin D, TNF-alpha exhibited no direct cytotoxic/cytostatic effect on the glioma cell lines tested. These results indicate that TNF-alpha can enhance the surface expression of HLA-ABC antigens on human glioma cells in the absence of a direct cytotoxic/cytostatic effect.
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PMID:Effects of recombinant human tumor necrosis factor-alpha on the surface phenotype and the growth of human malignant glioma cell lines. 314

The secretion of transforming growth factor-beta (TGF-beta), a growth inhibitory factor with immunosuppressive properties, was investigated in one glioblastoma cell line and seven surgically resected malignant glioma cells. Cultured cells from surgically resected tumors were examined immunohistochemically for glial fibrillary acidic protein (GFAP) and S-100 protein. The levels of TGF-beta 1 and TGF-beta 2 in culture supernatants from malignant glioma cells were determined by a specific bioassay using anti-TGF-beta 1 and anti-TGF-beta 2 antibodies. Two glioblastoma cell lines were cultured in the presence of TGF-beta 1 or TGF-beta 2 to assess the effect of TGF-beta on the growth of glioblastoma cells. Cultured cells from surgically resected tumors were positive for both GFAP and S-100 protein. Both active and latent forms of TGF-beta 1 and TGF-beta 2 were detected in the culture supernatants from malignant gliomas, except in one patient with anaplastic astrocytoma which secreted only latent forms of TGF-beta 1 and TGF-beta 2. There was no statistical difference in the levels of TGF-beta 1 and TGF-beta 2 in glioblastomas and anaplastic astrocytomas. Neither TGF-beta 1 nor TGF-beta 2 affected the growth of glioblastoma cells. These findings suggest that most malignant glioma cells secrete both TGF-beta 1 and TGF-beta 2, can convert TGF-beta from a latent to active form, and may suppress cytokine secretion by activated lymphocytes in vivo as well as in vitro.
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PMID:Secretion of transforming growth factor-beta 1 and -beta 2 by malignant glioma cells. 747 84

A novel approach toward the treatment of glioma was developed in a murine model. The genes for both interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) were first transfected into a mouse fibroblast cell line that expresses defined major histocompatibility complex (MHC) determinants (H-2k). The double cytokine-secreting cells were then cotransplanted intracerebrally with the Gl261 murine glioma cell line into syngeneic C57BL/6 mice (H-2b) whose cells differed at the MHC from the cellular immunogen. The results indicate that the survival of mice with glioma injected with the cytokine-secreting allogeneic cells was significantly prolonged, relative to the survival of mice receiving equivalent numbers of glioma cells alone. Using a standard 51Cr-release assay, the specific release of isotope from labeled Gl261 cells coincubated with spleen cells from mice injected intracerebrally with the glioma cells and the cytokine-secreting fibroblasts was significantly higher than the release of isotope from glioma cells coincubated with spleen cells from nonimmunized mice. The cellular antiglioma response was mediated by natural killer/lymphokine-activated killer and Lyt-2.2+ (CD8+) cells. The increased survival of mice with glioma and the specific immunocytotoxic responses after immunization with fibroblasts modified to secrete both IL-2 and IFN-gamma indicate the potential of an immunotherapeutic approach to gliomas with cytokine-secreting cells.
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PMID:Prolonged survival of mice with glioma injected intracerebrally with double cytokine-secreting cells. 749 Jun 18

We have examined the induction of nitric oxide synthase (NOS) activity in the rat astrocyte-derived C6 glioma cell line. In contrast to the previous results with primary astrocyte cultures, incubation of C6 cells with bacterial endotoxin lipopolysaccharide (LPS; 1 microgram/ml for 24 h) did not stimulate NO2 production. However, addition of either tumor necrosis factor-alpha (TNF-alpha) or interferon-gamma (IFN-gamma), cytokines that by themselves had no effect on NOS activity, imparted LPS responsiveness onto these cells in a dose-dependent manner (EC50 values of 39 ng/ml of TNF-alpha and 9.4 U/ml of IFN-gamma), and the effect of TNF-alpha could be further potentiated (twofold) by the presence of interleukin-1 beta. The simultaneous presence of TNF-alpha and IFN-gamma yielded a greater response than either cytokine alone; however, the respective EC50 values were not affected. A cytoplasmic extract from induced C6 cells catalyzed the Ca(2+)-independent conversion of L-arginine to L-citrulline, with an apparent Km of 51.2 microM, and this activity could be blocked by L-arginine analogues in the potency order amino > methyl > nitroarginine. Immunoblot analysis revealed an apparent molecular mass of 125 kDa for the NOS protein induced in C6 cells. These results indicate that the combination of LPS plus cytokines can induce NOS activity in C6 glioma cells with properties similar to those of the enzyme expressed in primary astrocyte cultures.
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PMID:Induction of nitric oxide synthase in rat C6 glioma cells. 750 14

The effects of irradiation on cytokine production in glioma cell lines, NP1, NP2 and NP3, were studied. Culture supernatants were collected after 6, 24, 48 or 72 hours and the concentrations of interleukin (IL)-6 and IL-8 measured by enzyme-linked immunosorbent assay. Spontaneous and IL-1 beta-stimulated productions were analyzed. Some cells were given a single dose of Lineac irradiation (10 or 20 Gy). Production of IL-6 (with or without IL-1 beta stimulation) increased gradually to a maximum after 72 hours, more in the 20 Gy-irradiated cells than 10 Gy cells (p < 0.01). Production of IL-8 increased gradually to a maximum after 48 or 72 hours. Spontaneous production of IL-8 increased more in 20 Gy-irradiated cells than 10 Gy cells after 6 and 24 hours (p < 0.01), but increased more in 10 Gy cells than 20 Gy cells after 48 and 72 hours (p < 0.01). The production of IL-8 stimulated by IL-1 beta increased more in 10 Gy cells than 20 Gy cells 24 hours later (p < 0.01). IL-6 and IL-8 production differed in the response to irradiation. Our data suggest that bidirectional communication between the immune system and glioma cells changes after radiotherapy.
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PMID:Effects of irradiation on cytokine production in glioma cell lines. 750 9

Rat brain glial cells have the capacity to express a calcium-independent form of nitric oxide synthase (iNOS). To test if iNOS induction required tyrosine kinase activity, we made use of genistein, a selective inhibitor of tyrosine kinases. In both primary astrocyte cultures and C6 glioma cells, the presence of genistein prevented both lipopolysaccharide- and cytokine-induced NOS activity in a dose-dependent manner. The presence of tyrphostin-25 (10 microM), which is highly specific for tyrosine kinases, also blocked iNOS induction. Additional characterization showed that genistein blocked iNOS induction in a dose-dependent manner (IC50 of approximately 40 microM), that the continuous presence of genistein was not necessary to observe inhibition, and that preincubation with genistein led to higher levels of inhibition than the simultaneous addition of genistein and inducers. The decrease in iNOS activity due to genistein was accompanied by a decrease in iNOS mRNA level as detected by a specific PCR assay. These results indicate that induction of astroglial iNOS expression requires tyrosine kinase activity.
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PMID:Nitric oxide synthase expression in glial cells: suppression by tyrosine kinase inhibitors. 750 17

Unconjugated monoclonal antibodies (mAb) kill tumor cells in vivo by activating immune functions. One of these is ADCC (antibody-dependent cellular cytotoxicity). The efficacy of mAbs might be augmented if the cytotoxic capacity of the effector cells could be increased. In this study the augmenting effect of granulocyte-colony-stimulating factor (G-CSF), granulocyte/macrophage(GM)-CSF and macrophage(M)-CSF was analyzed. Effector cells [peripheral blood mononuclear cells (PBMC) or granulocytes] were activated for 4-6 h by the respective CSF and assayed in an 18-h Cr51-release assay. Human colorectal, lymphoma, glioma and melanoma cell lines were target cells. Mouse mAbs of different isotypes, as well as chimeric and humanized mAbs, were used. mAbs having the human Fc part of the IgG molecule were the most effective. The killing capacity of PBMC as well as of granulocytes was statistically significantly enhanced when mAbs were added. M-CSF and GM-CSF were the best CSF for augmenting the lytic capacity of PBMC in ADCC. G-CSF had no significant effect on PBMC. Spontaneous cytolysis of PBMC was significantly augmented only by M-CSF. Granulocytes were, in general, significantly less effective than PBMC but may be equally effective killer cells together with mouse or human mAbs of the IgG1 isotype, particularly against melanoma cells. Granulocytes may also be significantly stimulated to increased lytic capacity when activated with G-CSF or GM-CSF. On the basis of the present evaluation, clinical trials in tumor patients are warranted, combining mAbs with GM-CSF or M-CSF. Preference might be given to GM-CSF as this cytokine activates both PBMC and granulocytes.
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PMID:Cytotoxicity of white blood cells activated by granulocyte-colony-stimulating factor, granulocyte/macrophage-colony-stimulating factor and macrophage-colony-stimulating factor against tumor cells in the presence of various monoclonal antibodies. 752 59

Interleukin 10 (Il-10) was initially discovered on the basis of its ability to suppress cytokine synthesis. Additionally, it can exert immunosuppressive effects on a variety of cell types. Since patients with malignant gliomas present with a general impairment of the immune system, we sought to investigate if IL-10 is expressed in the glioma tissue. Using RT-PCR, IL-10 mRNA levels were determined in 37 glial tumors of different grades including 2 recurrencies, 3 specimens from normal brain tissue and 3 glioblastoma cell lines. Expression of IL-10 mRNA was demonstrable in all tumors as well as in normal brain. High grade tumors and recurrent cases expressed significantly higher amounts of IL-10 specific mRNA compared to low grade tumors, while 2 out of 3 cell lines showed only weak constitutive expression. We suggest, that IL-10 may contribute to the progression of astrocytomas by allowing the tumor cells to attenuate the T-cell immune response and evade immune detection.
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PMID:[Increased amounts of IL-10 mRNA in anaplastic astrocytomas and glioblastoma multiforme]. 753 12

To study the potential interaction between cytokine and serotonin (5-HT) signal transduction, we evaluated the effect of interleukin-1 beta (IL-1 beta) on the 5-HT2 receptor-mediated mobilization of intracellular Ca2+ in cultured rat C6BU-1 glioma cells. Pretreatment of cells with IL-1 beta significantly inhibited the 5-HT-induced mobilization of Ca2+ in a dose (30-1000 U/ml)- and time (12-24 h)-dependent manner. Inhibition was observed when cells were stimulated with concentrations of 5-HT of > or = 1 microM, which induced the maximal 5-HT response. Lipopolysaccharide (1 microgram/ml) also inhibited 5-HT-induced Ca2+ mobilization, but heat-inactivated IL-1 beta as well as interferon-alpha (1000 U/ml), interferon-gamma (1000 U/ml), and tumor necrosis factor-alpha (2000 U/ml) did not. The inhibitory effects of IL-1 beta and LPS were significantly prevented by genistein, a selective tyrosine kinase antagonist, and by H7, a potent inhibitor of protein kinase C. These results indicate that IL-1 beta and LPS inhibit 5-HT2 receptor-mediated Ca2+ mobilization via pathways that include the activation of a tyrosine kinase and protein kinase C. The interaction between cytokines (IL-1 beta) and monoamines (5-HT) may serve to modulate signal transduction in the central nervous system.
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PMID:Inhibition of serotonin-induced Ca2+ mobilization by interleukin-1 beta in rat C6BU-1 glioma cells. 755 6


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