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)

Lactate dehydrogenase (LDH, EC 1.1.1.27) catalyzes an exchange reaction between pyruvate and lactate. It is demonstrated here that this reaction is sufficiently fast to cause a significant magnetization (saturation) transfer effect when the 13C resonance of pyruvate is saturated by a continuous-wave (CW) RF pulse. Infusion of [2-(13)C]glucose was used to allow labeling of pyruvate C2 at 207.9 ppm to determine the pseudo first-order rate constant of the unidirectional lactate-->pyruvate flux in vivo. During systemic administration of GABAA receptor antagonist bicuculline, this pseudo first-order rate constant was determined to be 0.08+/-0.01 s-1 (mean+/-SD, N=4) in halothane-anesthetized adult rat brains. In 9L and C6 rat glioma models, the 13C saturation transfer effect of the LDH reaction was also detected in vivo. Our results demonstrate that the 13C magnetization transfer effect of the LDH reaction may be useful as a novel marker for utilizing noninvasive in vivo MRS to study many physiological and pathological conditions, such as cancer.
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PMID:In vivo 13C saturation transfer effect of the lactate dehydrogenase reaction. 1726 Mar 57

Potassium channels are ubiquitous in cells and serve essential functions in physiology and pathophysiology. Potassium channel blockers have been shown to block tumour growth by arresting cells at the G(0)/G(1) checkpoint of the cell cycle. We investigated the effect of quinidine and caesium (Cs(+)) on cell proliferation, LDH (lactate dehydrogenase) release, free internal calcium, membrane potential, polyamine concentration, ODC (ornithine decarboxylase) activity and polyamine uptake in C6 glioma cells. The EC(50) for reducing cell proliferation was 112 microM for quinidine, whereas Cs(+) was less effective with an EC(50) of 4.75 mM. KCl or sucrose did not affect proliferation. LDH release was augmented by quinidine. Quinidine caused a transient increase in free internal calcium but decreased calcium after a 48 h incubation period. Further 300 microM quinidine depolarized the cell membrane in a similar range as did 30 mM KCl. Quinidine decreased cellular putrescine beyond detection levels while spermidine and spermine remained unaffected. ODC activity was reduced. Addition of putrescine could not override the antiproliferative effect owing to a reduced activity of the polyamine transporter. Our study indicates that the antiproliferative effect of quinidine is not due to a simple membrane depolarization but is caused by a block of ODC activity.
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PMID:Potassium channel blockers quinidine and caesium halt cell proliferation in C6 glioma cells via a polyamine-dependent mechanism. 1737 Dec 84

Glioblastoma multiformes (GBMs) express increased aquaporin (AQP) 1 compared to normal brain. AQPs may contribute to edema, cell motility, and shuttling of H(2)O and H(+) from intracellular to extracellular space. We sought to gain insight into AQP1 function in GBM. In cultured 9L gliosarcoma cells, AQP1 expression was induced by dexamethasone, platelet-derived growth factor, NaCl, hypoxia, D-glucose (but not L-glucose), and fructose. Induction of AQP1 expression correlated with the level of glycolysis, maximized by increasing medium D-glucose or fructose and decreasing O(2), and was quantified by measuring lactate dehydrogenase (LDH) activity and medium lactate concentration. Upregulation of the protease cathepsin B was also observed in 9L cells cultured under glycolytic conditions. Immunohistochemical staining of human GBM specimens revealed increased coincident expression of AQP1, LDH, and cathepsin B in glioma cells associated with blood vessels at the tumor periphery. GBMs are known to exhibit aerobic glycolysis. Increased glucose metabolism at the tumor periphery may provide a scenario by which upregulation of AQP1, LDH, and cathepsin B contributes to acidification of the extracellular milieu and to invasive potential of glioma cells in perivascular space. The specific upregulation and metabolic consequences of increased AQP1 in gliomas may provide a therapeutic target, both as a cell surface marker and as a functional intervention.
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PMID:Regulation and function of aquaporin-1 in glioma cells. 1789 73

The protein tyrosine kinase inhibitor, genistein, has been reported to inhibit proliferation and to induce cell death in various non-solid and solid cancer cell lines. Herein, we examined the effects of genistein in several human malignant glioma cell lines. We found that genistein inhibited the proliferation of LN-18, LNT-229, LN-308 and T98G cells at EC50 concentrations of 25-80 microM (72 h of exposure). The growth of a non-neoplastic immortalized human astrocyte cell line, SV-FHAS, was inhibited at similar concentrations. There was a reduction in [3H]-methylthymidine incorporation and a moderate lactate dehydrogenase release as a sign of cell death in genistein-treated glioma cells. Electron microscopy showed morphological changes with mitochondrial swelling and apoptosis in glioma cells treated with high concentrations of genistein. Genistein-induced cytotoxicity was associated with an increased DNA/topoisomerase II complex formation. Furthermore, genistein induced cell cycle arrest in G2/M. There was an increase in the p53 and p21 levels in response to genistein. However, there was no difference in genistein sensitivity between p21-deficient colon carcinoma cells and isogenic control cells. Genistein-induced cell death in LN-18 and LNT-229 was unaffected by the ectopic expression of the preferential caspase 1/8 inhibitor, crm-A, or co-exposure to the pan-specific pseudosubstrate caspase inhibitor, zVAD-fmk. The ectopic expression of the anti-apoptotic BCL-2 protein attenuated the cytotoxic effects of genistein. Moreover, the ectopic expression of temperature-sensitive p53V135A, which acts as a dominant-negative p53 mutant at 38.5 degrees C but assumes p53 wild-type properties at 32.5 degrees C, in LN-18 or LNT-229 cells, had no effect on genistein cytotoxicity at either temperature. Genistein did not act in synergy with CD95 ligand-induced apoptosis or various cancer chemotherapy drugs in cytotoxic or clonogenic cell death assays. Thus, genistein-like protein kinase inhibitors are promising agents for the experimental treatment of malignant gliomas.
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PMID:The topoisomerase II inhibitor, genistein, induces G2/M arrest and apoptosis in human malignant glioma cell lines. 1835 97

Dibromoacetonitrile (DBAN) is a disinfection byproduct of water chlorination. The present study was designed to investigate the potential oxidative protein modifications and alterations in proteasomal activity induced by DBAN in C6 glioma cells (C6 cells). Cells were exposed to 50-400 ppb DBAN for 24 h or 48 h. Cellular viability and lactate dehydrogenase (LDH) leakage were unaffected at 24 h. However, at 48 h after exposure to high concentrations of DBAN, there was a significant decrease in cell viability accompanied by a significant increase in LDH leakage. Exposure to DBAN for 48 h significantly enhanced formation of reactive oxygen species (ROS) in a concentration-related manner. Incubation of C6 cells for 24h or 48 h caused 1.3-2.4-fold increase in levels of lipid peroxidation as indicated by malondialdehyde (MDA)+4-hydroxy-2(e)-nonenal (4-HNE). Further, DBAN induced a concentration and time-dependent increase (1.6-6-folds) in the levels of protein carbonylation. At 48 h, proteasomal activities were found to decrease to 80%, 72%, 46%, and 34% of control with 50 ppb, 100 ppb, 200 ppb, 400 ppb DBAN, respectively. In conclusion, the present study indicates that exposure of C6 cells to DBAN results in generation of ROS, lipid peroxidation, accumulation of oxidized proteins and inhibition of proteasomal activity.
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PMID:Dibromoacetonitrile-induced protein oxidation and inhibition of proteasomal activity in rat glioma cells. 1848 29

Okadaic acid (OA) is a polyether fatty acid produced mainly by dinoflagellates causing diarrhoeic shellfish poisoning (DSP) in humans. To resolve the controversies concerning its genotoxicity in vitro, we have investigated eventual specific cellular response in DOK, Caco-2 (Deltap53/p53(-)), HepG-2 and C6 glioma cells using the DNA damage detection test (3d DNA repair test: nucleotide excision repair (NER) and base excision repair (BER)), caspase-3-triggered apoptosis, neutral red (NR) and lactate dehydrogenase (LDH) release tests. At low concentrations of OA (10nM), cytotoxicity measured by LDH release is more marked in DOK cells, indicating necrotic cell death that occurs only slightly in HepG-2 cells. At the same concentration, caspase-3 activation-dependent apoptosis and DNA damage caused by OA were only detected in HepG-2 cells. This apoptosis appears to be p53 gene dependent. Cell death occurs in the other cell types only by necrosis at OA concentrations amended to cultures. Among the tested cell lines, HepG-2 cells are the most sensitive to OA (10-50nM) at 12 and 72h as revealed by the NR test. The 3D test shows that only HepG-2 cells bear damaged DNA at tested concentrations. It is concluded that the genotoxicity of OA is chiefly cell type dependent and concentration dependent, giving sense to controversial genotoxicity data found in the literature.
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PMID:The cytotoxicity and genotoxicity of okadaic acid are cell-line dependent. 1853 64

Resveratrol is a naturally occurring polyphenolic compound highly enriched in grapes, peanuts, red wine, and a variety of food sources. Sulforaphane belongs to the family of isothiocyanates and is highly enriched in cruciferous vegetables. Our previous study showed that resveratrol, when used at high concentrations, inhibited cell proliferation, caused the cell cycle arrest and induced apoptotic cell death in glioma cells. In the current study, we tested the effect of combination treatment with resveratrol and sulforaphane, when both were used at low concentrations, on cell proliferation, migration and death in human U251 glioma cells. Our study shows that combination treatment with resveratrol and sulforaphane inhibits cell proliferation and migration, reduces cell viability, induces lactate dehydrogenase release, decreases pro-survival Akt phosphorylation and increases caspase-3 activation. The use of combination of bioactive food components, such as resveratrol and sulforaphane, may be a viable approach for the treatment of glioma.
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PMID:Combination treatment with resveratrol and sulforaphane induces apoptosis in human U251 glioma cells. 1968 89

Many naturally occurring substances of plant origin ingested in human diet, exhibit anticarcinogenic and antimutagenic effects. One of the active phytochemical which shows the active anticarcinogenic role is Piper longum Linn. (Pl). Pl is widely used in ayurvedic industry due to its property in healing some of the bodily ailments. Despite being known for the antioxidant, antimicrobial and anticarcinogenic effects, its relation to brain and its tumour development is still scarce. Hence, the experimental glioma model was developed in rats using C6 glioma cells and the effect of Pl was evaluated in the brain tissue of experimental group of rats. From the study, the glioma induced animals showed an increased level of lipid peroxides (LPO), tissue marker enzymes lactate dehydrogenase (LDH), creatine kinase (CK), 5'nucleotidase (5'ND) and acetylcholine esterase (AChE). But Pl treatment (20 mg/kg body weight) significantly attenuated these alterations thereby showing potent anticancer effect in glioma induced rats. In addition, the anticarcinogenic effect of Pl was confirmed by microscopic analysis and the restoration of increased lipids and protein bound carbohydrates (PBCs) in the brain tissue of glioma induced rats. Hence our results implicate a major role for Pl in preventing the cancer development in the experimental glioma model.
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PMID:Studies on the neuroprotective role of Piper longum in C6 glioma induced rats. 1973 Jul 92

The present study describes the synthesis and anticancer activity of novel octahedral Pt(IV) complexes with cyclohexyl functionalized ethylenediamine-N,N'-diacetate-type ligands. Molecular mechanics calculations and density functional theory analysis revealed that s-cis is the preferred geometry of these Pt(IV) complexes with tetradentate-coordinated (S,S)-ethylenediamine-N,N'-di-2-(3-cyclohexyl)propanoate. The viability of cancer cell lines (U251 human glioma, C6 rat glioma, L929 mouse fibrosarcoma, and B16 human melanoma) was assessed by measuring mitochondrial dehydrogenase activity and lactate dehydrogenase release. Cell-cycle distribution, oxidative stress, caspase activation, and induction of autophagy were analyzed by flow cytometry using appropriate fluorescent reporter dyes. The cytotoxic activity of novel Pt(IV) complexes against various cancer cell lines (IC(50) range: 1.9-8.7 microM) was higher than that of cisplatin (IC(50) range: 10.9-67.0 microM) and proceeded through completely different mechanisms. Cisplatin induced caspase-dependent apoptosis associated with the cytoprotective autophagic response. In contrast, the new Pt(IV) complexes caused rapid, caspase-independent, oxidative stress-mediated non-apoptotic cell death characterized by massive cytoplasmic vacuolization, cell membrane damage, and the absence of protective autophagy.
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PMID:Synthesis and in vitro anticancer activity of octahedral platinum(IV) complexes with cyclohexyl-functionalized ethylenediamine-N,N'-diacetate-type ligands. 2040 61

We have examined the effect of a physiological concentration of l-triiodothyronine on the activity of cytosolic enzymes in the C6 rat glioma cell line. l-Triiodothyronine decreased glycerol phosphate dehydrogenase activity. This effect seems to be rather specific, since l-triiodothyronine did not change malic enzyme or lactate dehydrogenase activity and did not alter the amount of either cytosolic or total cell protein. Dexamethasone greatly increased glycerol phosphate dehydrogenase and l-triiodothyronine also decreased the response to the glucocorticoid. Noradrenaline or dibutyryl cyclic AMP potentiated the dexamethasone-induced specific activity of this enzyme, and l-triiodothyronine lowered the response to the combined effects of these agents. The effect of l-triiodothyronine is not restricted to the C6 cells, since it also decreased basal glycerol phosphate dehydrogenase activity in primary cultures of cells dissociated from brains of embryonic mice. The results indicate that thyroid hormones have a direct effect on the modulation of cytosolic glycerol phosphate dehydrogenase in cultured cells of glial origin.
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PMID:Multihormonal control of proliferation and cytosolic glycerol phosphate dehydrogenase, lactate dehydrogenase and malic enzyme in glial cells in culture. 2049 23


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