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)

The prognosis for patients with the high-grade cerebral glioma glioblastoma multiforme is poor. The median survival for primary tumors is < 12 months, with most recurring at the site of the original tumor, indicating that a more aggressive local therapy is required to eradicate the unresectable "nests" of tumor cells invading into adjacent brain. Two adjuvant therapies with the potential to destroy these cells are porphyrin-sensitized photodynamic therapy (PDT) and boron-sensitized boron neutron capture therapy (BNCT). The ability of a boronated porphyrin, 2,4-(alpha, beta-dihydroxyethyl) deuteroporphyrin IX tetrakiscarborane carboxylate ester (BOPP), to act as a photosensitizing agent was investigated in vitro with the C6 rat glioma cell line and in vivo with C6 cells grown as an intracerebral tumor after implantation into Wistar rats. These studies determined the doses of BOPP and light required to achieve maximal cell kill in vitro and selective tumor kill in vivo. The data show that BOPP is more dose effective in vivo by a factor of 10 than the current clinically used photosensitizer hematoporphyrin derivative and suggest that BOPP may have potential as a dual PDT/BNCT sensitizer.
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PMID:Selective tumor kill of cerebral glioma by photodynamic therapy using a boronated porphyrin photosensitizer. 861 57

1. The coding sequence of the P2Y1-purinoceptor was cloned from a human genomic library. 2. The open reading frame encodes a protein of 373 amino acids that is 83% identical to the previously cloned chick and turkey P2Y1-purinoceptor and is > or = 95% homologous to the recently cloned rat, mouse, and bovine P2Y1-purinoceptors. 3. The human P2Y1-purinoceptor was stably expressed in 1321N1 human astrocytoma cells using a retroviral vector. Although the P2Y1-purinoceptor agonist, 2MeSATP, had no effect on inositol phosphate accumulation in cells infected with the P2Y1-purinoceptor virus. No effect of 2MeSATP on cyclic AMP accumulation was observed in P2Y1-receptor-expressing 1321N1 cells. 4. The pharmacological selectively of 18 purinoceptor agonists was established for the expressed human P2Y1-purinoceptor. 2MeSATp was more potent than ATP but less potent than 2MeSADP. ADP also was more potent than ATP. A similar maximal effect was observed with most agonists tested. However, alpha, beta-MeATP had no effect and 3'-NH2-3'-deoxyATP and A2P4 were partial agonists. The order of potency of agonists for activation of the turkey P2Y1-purinoceptor, also stably expressed in 1321N1 cells, was identical to that observed for the human P2Y1-purinoceptor. 5. C6 glioma cells express a P2Y-purinoceptor that inhibits adenylyl cyclase but does not activate phospholipase C. Expression of the human P2Y1-purinoceptor in C6 cells conferred 2MeSATP-stimulated inositol lipid hydrolysis to these cells. The phospholipase C-activating human P2Y1-purinoceptor could be delineated from the endogenous P2Y-purinoceptor of C6 glioma cells by use of the P2-purinoceptor antagonist, PPADS, which blocks the P2Y1-purinoceptor but does not block the endogenous P2Y-purinoceptor of C6 cells. P2-purinoceptor agonists also exhibited differential selectivities for activation of these two P2Y-purinoceptors.
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PMID:Second messenger cascade specificity and pharmacological selectivity of the human P2Y1-purinoceptor. 873 91

Phosphatidylcholine (PtdCho) can provide lipid second messengers involved in signal transduction pathways. As a measure of phospholipid turnover in response to extracellular stimulation, we investigated differential enhancement of [3H]choline incorporation into PtdCho by phorbol esters. In C6 rat glioma and SK-N-SH human neuroblastoma cells, [3H]PtdCho synthesis was 2-4 fold stimulated by beta-12-O-tetradecanoylphorbol-13-acetate (beta-TPA) when [3H]choline was incubated simultaneously with, or 15 min prior to, beta-TPA treatment. By contrast, in N1E-115 mouse and SK-N-MC human neuroblastoma cells, phorbol esters had no appreciable effect on [3H]choline incorporation; however, in all cells, 200 microM oleic acid enhanced PtdCho synthesis, indicating a stimulable process. Alterations by thymeleatoxin (TMT), an activator of conventional PKC isoforms (alpha, beta and gamma), were similar to beta-TPA. We investigated whether expression of specific PKC isoforms might correlate with these effects of phorbol esters on PtdCho synthesis. All cell lines bound phorbol esters, had PKC activity that was translocated by phorbol esters and differentially expressed isoforms of PKC. Northern and western blot analyses, using specific cDNA and antibodies for PKC-alpha, -beta, -gamma, -delta, -epsilon, and -zeta, revealed that expression of alpha-isoform predominated in C6 and SK-N-SH cells. In contrast, TPA-responsive beta-isoform predominated in SK-N-MC cells. gamma-PKC was not detected in any cells and only in C6 cells was PKC-delta present and translocated by beta-TPA treatment. PKC-epsilon was not detected in SK-N-MC cell lines but translocated with TPA treatment in the other three cell lines. PKC-zeta was present in all cells but was unaltered by TPA treatment. Accordingly, stimulation of PtdCho turnover by phorbol esters correlated only with expression of PKC-alpha; presence of PKC-beta alone was insufficient for a TPA response.
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PMID:Phorbol ester stimulation of phosphatidylcholine synthesis in four cultured neural cell lines: correlations with expression of protein kinase C isoforms. 878 1

In neuroblastoma X glioma hybrid NG108-15 cells, P2 purinoceptor agonists inhibited forskolin-stimulated cyclic AMP accumulation with distinct selectivities and their activities could be partially reversed by P2 purinoceptor antagonists. The rank order of potency in inhibition of cyclic AMP accumulation was UTP > 2 methylthio-ATP (MeSATP) > benzoylbenzoic ATP (BzATP) = alpha, beta-methylene ATP (AMPCPP) > beta, gamma-methylene ATP (AMPPCP) > ATP > ADP > adenosine 5'-thiotriphosphate (ATP gamma S). Neither adenosine nor AMP caused any inhibitory effect on cyclic AMP accumulation. Pertussis toxin treatment of cells attenuated the inhibitory effect of UTP, MeSATP and ATP on cyclic AMP accumulation whereas it had no effect on the BzATP-induced response. In addition, P2-purinoceptor-mediated inhibition of cyclic AMP accumulation was insensitive to cytosolic Ca2+ concentration. The breakdown of cyclic AMP was enhanced by MeSATP but not by the addition of ATP, UTP and BzATP. Our results suggest that a pertussis toxin-sensitive Gi signalling pathway is directly coupled to the occupancy of P2u and P2y receptors in NG108-15 cells.
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PMID:P2 purinoceptor-mediated inhibition of cyclic AMP accumulation in NG108-15 cells. 889 31

The invasion/migration of two cell lines, melanoma (MEW) and glioma (BT5C), and their counterparts treated for prolonged time with TPA were studied. On Western blots both cell lines expressed alpha, beta I protein kinase C isoforms, whereas beta II and gamma were not detected. The down-regulation of alpha and beta I PKC was observed in glioma cells after long treatment with TPA, whereas the same treatment of melanoma cells did not lead to PKC downregulation. The down-regulation of PKC was accompanied by stimulation of cell migration/invasion through Transwell chambers coated with collagen IV or fibronectin. In the case of melanoma cells treated with TPA, whose PKC was not down-regulated, the inhibition of migration/invasion was observed. The invasive properties of studied cells did not correlate with any conventional PKC isoform expression.
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PMID:The pleiotropic effect of TPA on in vitro invasion/migration of glioma and melanoma cell lines. 894 14

The absorption and emission spectra, fluorescence quantum yields and lifetimes and triplet state properties of a boronated porphyrin, the tetrakiscarborane carboxylate ester of 2,4-(alpha, beta-dihydroxyethyl) deuteroporphyrin IX (BOPP), have been determined. This compound is an alternative photodynamic therapy (PDT) agent that exhibits highly selective tumor localization, with the potential to be used in conjunction with boron neutron capture therapy. The photophysical characteristics of BOPP are similar to other porphyrins and it exhibits marked aggregation and acid-base speciation under typical physiological conditions. In particular, protonation of the porphyrin imino (-N=) nitrogens occurs in the pH 5-7 region and influences the photophysical properties. Time-resolved confocal fluorescence imaging of the intracellular distribution of BOPP in C6 glioma cells indicates distinct subcellular localization and heterogeneity of emission. The results are interpreted and discussed in terms of the possible mechanisms for cellular uptake and localization.
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PMID:Photophysics and intracellular distribution of a boronated porphyrin phototherapeutic agent. 897 41

Effects of thrombin on brain cells, including change of neurite outgrowth and astrocyte shape, are described, but the molecular mechanisms are unclear. We investigated the effects of human alpha-thrombin and a six amino acid thrombin receptor activating peptide (TRAP-6, SFLLRN) on [Ca2+]i, phosphoinositide hydrolysis, and protein kinase C in rat glioma C6 cells. Stimulation of C6 cells with both alpha-thrombin and TRAP-6 resulted in [Ca2+]i mobilization, [3H]Inositol phosphate response, and enhanced immunoreactivity of the protein kinase C (PKC) isoenzymes alpha, beta, gamma, delta, and epsilon. Results suggest that alpha-thrombin and TRAP-6 activate at least partially the same intracellular signaling pathways in rat glioma C6 cells, which is evidence for involvement of "tethered ligand" receptor in thrombin induced signaling in glioma C6 cells.
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PMID:Signaling effects of alpha-thrombin and SFLLRN in rat glioma C6 cells. 897 98

Modulation of protein phosphorylation activities by insulin was investigated in glioma and normal glial cells. Insulin suppressed the in vitro protein phosphorylation of glioma cells in a dose-dependent manner while it stimulated that of meningiomas, neurilemmomas and glial cells. Although gliomas and glial cells contained different species of tyrosyl phosphoproteins before treatment, they expressed similar kinds of tyrosyl phosphoproteins in response to insulin. Insulin increased the activities of casein kinase II and total protein kinase C (PKC) in glioma and normal glial cells. The membrane-bound PKC activity in U373-MG cells was elevated by insulin. The PKC isozymes, including subtypes alpha, beta, delta, epsilon and gamma, were detected in gliomas, but few were found in glial cells. Insulin down regulated the cytosolic PKC-gamma and the membrane-bound PKC-epsilon proteins in gliomas. These results indicate that an altered insulin signaling pathway exists in human gliomas, which might involve differential regulation of PKC isozymes.
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PMID:Effects of insulin on protein phosphorylation and protein kinase C activity in human malignant gliomas. 953 17

The molecular pathways by which the cyclopentenone prostaglandins (PGA and PGJ series) inhibit cell growth and tumorigenicity are poorly understood. These cellular responses may be caused by specific regulation of growth-related and stress-induced genes. A variety of prostaglandins were tested for their ability to regulate insulin-like growth factor-I (IGF-I) and Waf1 gene expression in C6 rat glioma cells. The prostaglandins (in order of potency) PGJ2 > PGA1 > PGA2, approximately PGD2 >> PGE2 all significantly repressed IGF-I gene expression. With the exception of PGE2, the same prostaglandins that repressed IGF-I also induced Waf1 gene expression. However, the order of potency for Waf1 induction was different than for IGF-I repression: PGA2 > PGA1 approximately PGJ2 > PGD2. The different order of potency of the prostaglandins in regulating IGF-I and Waf1 gene expression suggests that different intracellular signals may be involved in regulating the two genes. Augmentation of glutathione levels by pretreatment of cells with N-acetyl-L-cysteine attenuated the effect of PGA2 on IGF-I and Waf1 gene expression. conversely, depletion of the intracellular glutathione pool by pretreatment with buthionine sulfoximine potentiated the effect of PGA2 on the expression of both genes. These results suggest that conjugation with glutathione prevents the regulation of gene expression by PGA2. We also tested the effect of several simpler compounds that contain a five-membered ring system on IGF-I and Waf1 gene expression. 2-Cyclopenten-1-one, but not cyclopentene or cyclopentene, repressed IGF-I and induced Waf1 gene expression, demonstrating the requirement for an alpha, beta-unsaturated carbonyl for regulation of the two genes. The dione compound 4-cyclopentene-1,3-dione, which has two potentially reactive carbons rather than one, was considerably more potent than 2-cyclopentene-1-one in repressing IGF-I gene expression (IC50 = 30 microM for 4-cyclopentene-1,3-dione as compared with 167 microM for 2-cyclopentene-1-one). Additional results indicated that diethyl maleate, which has two alpha,beta-unsaturated carbonyls in a non-cyclic configuration, also repressed IGF-I gene expression (IC50 = 214 microM) and induced Waf1 gene expression, indicating that the cyclic structure is not required for either effect.
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PMID:Effects of cyclopentenone prostaglandins and related compounds on insulin-like growth factor-I and Waf1 gene expression. 954 24

We examined the modulation of protein kinase C (PKC) subtypes during apoptosis induced by ginsenoside Rh2 (G-Rh2) in human neuroblastoma SK-N-BE(2) and rat glioma C6Bu-1 cells. Apoptosis induced by G-Rh2 in both cell lines was confirmed, as indicated by DNA fragmentation and in situ strand breaks, and characteristic morphological changes. During apoptosis induced by G-Rh2 in SK-N-BE(2) cells, PKC subtypes alpha, beta and gamma were progressively increased with prolonged treatment, whereas PKC delta increased transiently at 3 and 6 h and PKC epsilon was gradually down-regulated after 6 h following the treatment. On the other hand, PKC subtype zeta markedly increased at 24 h when maximal apoptosis was achieved. In C6Bu-1 cells, no significant changes in PKC subtypes alpha, gamma, delta, epsilon and zeta were observed during apoptosis induced by G-Rh2. These results suggest the evidence for a possible role of PKC subtype in apoptosis induced by G-Rh2 in SK-N-BE(2) cells but not in C6Bu-1 cells, and raise the possibility that G-Rh2 may induce apoptosis via different pathways interacting with or without PKC in different cell types.
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PMID:Differential expression of protein kinase C subtypes during ginsenoside Rh2-lnduced apoptosis in SK-N-BE(2) and C6Bu-1 cells. 1105 34


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