Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0017636 (glioblastoma)
 18,345 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Three cell lines established from human gliomas were found to differ in the capacity to phosphorylate the glycolytic enzyme pyruvate kinase in vitro. Phosphorylation in the glioblastoma cell line U-138 was more pronounced than in the glioma cell line Hs 683 and in the glioblastoma cell line A-172. All 3 cell lines showed similar pyruvate kinase isozyme patterns and expressed about 90% K-type and 10% M-type subunits. So, differences in pyruvate kinase phosphorylation could not be explained by differences in the availability of the appropriate substrate, being pyruvate kinase type K. As in gliomas, phosphorylation could specifically and almost completely be inhibited by fructose-1,6-bisphosphate. In order to investigate a potential physiological significance of the phosphorylation of pyruvate kinase, we have characterized these cell lines for several glycolytic parameters. In U-138 cells, the production of lactate appeared to be 2 times higher as compared with A-172 and Hs 683 cells under normal growth conditions and even 4 times higher under low glucose culture regime. The efflux of lactate correlated with the pyruvate kinase phosphorylation pattern in the cell lines. In none of the cell lines could the lactate production be stimulated by glutamine as additional energy source under low glucose culture conditions. The higher glycolytic flux in U-138 cells was not accompanied by higher glycolytic enzyme activities. The isozyme patterns of hexokinase, pyruvate kinase, aldolase, enolase and lactate dehydrogenase in the cell lines were nearly identical and resembled the patterns previously described for solid gliomas. However, the isozyme composition of phosphofructokinase in the cell lines differed from the situation in gliomas. While in gliomas the expression of L-type phosphofructokinase is favored, in the glioma cell lines, we found an increase in the expression of C-type subunits.
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PMID:Phosphorylation of pyruvate kinase and glycolytic metabolism in three human glioma cell lines. 179 9

As previously reported, cytotoxic synergy is produced when clinically achievable concentrations of cytarabine (Ara-C) and hydroxyurea (HU) are used as potential inhibitors of in vitro DNA repair in cisplatin (cis-Pt)-treated human colon carcinoma cells. This pilot study was subsequently designed to duplicate the in vitro dose and schedule and to determine the toxicity of this three-drug combination in two cohorts of patients. 21 patients had received prior chemotherapy and 19 were not previously treated. All patients had refractory solid tumors. They received monthly cycles of an oral loading dose of 800 mg/m2 HU followed every 2 h by 6 oral doses of 400 mg/m2, a 12-h continuous infusion of 200 or 250 mg/m2/h Ara-C concurrent with the HU, and then 100 mg/m2 cis-Pt over 1 h. A total of 95 cycles were given with the expected toxicities of nausea and vomiting and fatigue but not major acute toxicity observed. Thrombocytopenia was significant but transient and was dose-limiting only for patients who had received prior therapy. The median platelet nadir after one cycle was 43,000/microliters for all patients and 67,000/microliters for those who had not undergone prior treatment. Azotemia was treatment-limiting in responding and stable patients, suggesting the possibility of synergistic nephrotoxicity. Interestingly, there were early transient rises in both uric acid and lactate dehydrogenase (LDH). Partial responses were seen in 9 of 32 patients with measurable disease and there was significantly improvement in 5 of 8 patients with only evaluable disease. The responses or improvement occurred in patients with non-small-cell lung cancer, breast carcinoma, glioblastoma, ovarian carcinoma, small-cell lung cancer, and mesothelioma. Of these 14 patients, 9 had failed prior chemotherapy regimens. Significantly, responses were observed in 3 of 8 patients who had previously received cis-Pt, suggesting that the HU/Ara-C combination modulated cis-Pt resistance. Because of these encouraging results, a second pilot study has been initiated with modifications dictated by the toxicity issues raised in this trial.
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PMID:Cisplatin preceded by concurrent cytarabine and hydroxyurea: a pilot study based on an in vitro model. 224 91

In an attempt to clarify the role of beta interferon in vitro cell systems, the metabolic expression of dihydrofolate reductase (DHFR), succinate dehydrogenase (SDH) and lactate dehydrogenase (LDH), by histochemical methods was studied. DHFR was also quantified by flow cytometry. Glioblastoma cell line with or without beta interferon was used. Three days after the treatment the DHFR reaction was much less intense than in the control. Quantitative data confirmed these results. Immediately afterwards, most cells exhibited much more intense reaction. These facts underlined that, in this biological model in vitro, beta interferon could reduce the synthesis of these enzymes only for a short period.
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PMID:[Qualitative and quantitative histochemical evaluation of the dehydrogenase activity in human glioblastoma cells treated with beta-interferon]. 237 36

We have previously shown that a recombinant carboxyl-terminal 105-amino-acid fragment (CT105) of the amyloid precursor protein (APP) induced strong non-selective inward currents in Xenopus oocytes. Here we investigated the toxic effect of CT105 peptide on the cultured mammalian cells. The CT105 peptide induced a significant lactate dehydrogenase (LDH) release from cultured rat cortical neurons and PC12 cells in a concentration (from 10 microM)- and time (from 48 h)-dependent manner. The toxic effect of CT105 was more potent than that of any fragments of amyloid beta protein (A beta). However, CT105 peptide did not affect the viability of U251 human glioblastoma cells. In contrast to CT105, A beta increased LDH release only slightly even at 50 microM but significantly inhibited 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction at submicromolar concentrations. Among the various neuroprotective drugs tested, only cholesterol, which alters membrane fluidity, could attenuate the cytotoxicity of CT105 significantly. The CT105 peptide formed multiple self-aggregates on solubilization. Pretreatment with a sublethal concentration of CT105 did not significantly alter the susceptibility of cells to hydrogen peroxide and glutamate. Endogenous CT peptides were found not only in the cell lysates but also in the conditioned medium of PC12 cells. These results imply that CT peptide can directly attack the cell membrane probably by making pores or nonselective ion channels, whereas A beta impairs the intracellular metabolic pathway first. Thus, it is thought that both CT and A beta, which are formed during the processing of APP, may participate in the neuronal degeneration in Alzheimer's disease by different mechanisms.
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PMID:Neurotoxicity of a carboxyl-terminal fragment of the Alzheimer's amyloid precursor protein. 875 24

Alterations in the p53 tumor-suppressor gene occur in 35-60% of human glioblastomas, and re-introduction of p53 can suppress neoplastic growth. To evaluate the potential for p53 gene therapy of glioblastoma, we have analyzed the response of human glioblastoma cell lines in vitro and in vivo to experimental therapy with replication-deficient recombinant adenoviruses encoding wild-type p53 (rAd-p53). Western blot analyses showed high-level expression of p53 protein after treatment with rAd-p53, and transgene expression was dependent on promoter strength. A p53-specific dose-dependent inhibition of in vitro cellular proliferation was observed in 5 of 6 cell lines, and growth inhibition corresponded to adenovirus-mediated gene transfer and expression. p53-specific cell death was quantitated by release of the lactate dehydrogenase enzyme. Fragmentation of DNA into nucleosomal oligomers and the occurrence of a hypodiploid cell population detected by flow cytometry provided evidence for apoptosis. Studies in nude mice demonstrated that ex vivo infection with rAd-p53 suppressed the tumorigenic potential of human glioblastoma cells. Furthermore, direct injection of rAd-p53 into established s.c. xenografts inhibited tumor growth. Our observations suggest that re-introduction of wild-type p53 may have potential clinical utility for gene therapy of glioblastoma.
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PMID:Adenovirus-mediated p53 gene transfer suppresses growth of human glioblastoma cells in vitro and in vivo. 882 52

Loss of chromosome 10 was observed in 10 out of 12 xenografted glioblastomas studied. Chromosome 10 carries the gene coding the hexokinase type 1 isoenzyme (HK-I), which catalyses the first step of glycolysis, which is essential in brain tissue and glioblastomas. We investigated the relationships between the relative chromosome 10 number, the amount of HK-I mRNA, HK-I activity and its intracellular distribution, and glycolysis-related parameters such as the lactate-pyruvate ratio, lactate dehydrogenase (LDH) and ATP contents. Individual tumour HK-I mRNA amounts were 23-65% lower than that of normal human brain and reflected the relative decrease of chromosome 10 number (alpha < 0.01). Total HK activities of individual glioblastomas varied considerably but were constantly (a mean of seven times) lower than that of normal brain tissue. The mitochondria-bound HK-I fraction of individual tumours was generally over 50%, compared with that of normal brain tissue. As shown by lactate - pyruvate ratios, in all the gliomas, glycolysis was elevated to an average of 3-fold that measured in normal brain. An elevated ATP content was also constantly noted. Adaptation of glioblastoma metabolism to the chromosome 10 loss and to the HK-I transcription unit emphasises the critical role of glycolysis in their survival. We hypothesise that HK-I, the enzyme responsible for initiating glycolysis necessary for brain function, may approach its lowest limit in gliomas, thereby opening therapeutic access to pharmacological anti-metabolites affecting energy metabolism and tumour growth.
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PMID:High glycolysis in gliomas despite low hexokinase transcription and activity correlated to chromosome 10 loss. 882 47

The cytotoxic effect of high-linear-energy transfer (LET) carbon beams on two human glioblastoma cell lines (A172 and TK1) was analyzed, especially concerning cell death, including apoptosis. Gamma-ray radiation was used for comparison. The results of standard colony formation assay showed that the survival fraction of each cell line decreased in an LET-dependent manner. The results of other direct cytotoxic assays, dye exclusion test, and lactate dehydrogenase (LDH) release assay, also displayed a similar relationship between the cytotoxic effect of carbon beams and LET. The maximum values of the cell death index (CDI) were 50.2% in A172 and 37.5% in TK1, both obtained on day 7 after exposure to carbon beams of 80 keV/microm. Apoptosis was observed only on days 4 and 7 after carbon beam irradiation, with maximum values of 7% in A172 and 4.5% in TK1, and the induction of apoptosis after high-LET radiation could be p53-independent. This indicated that a combination of multiple assays to detect cell death was important in evaluating the radiosensitivity of tumor cells, because this approach could more precisely reflect the clinical effectiveness of radiotherapy.
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PMID:Cell death induced by high-linear-energy transfer carbon beams in human glioblastoma cell lines. 1032 42

Between August 1986 and December 1997, 149 patients with glioblastoma were treated postoperatively with 1.5 Gy fractions three times daily to a total dose of 54 Gy with 4-h intervals. Median actuarial survival was 8.8 months. Survival was 31% at 12 months and 4% at 24 months. No severe acute toxicity occurred. Multivariate analysis revealed that only age < or = 60 years and lactate dehydrogenase levels < or = 240 U/l predicted significantly higher survival probabilities.
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PMID:Accelerated hyperfractionated radiotherapy in 149 patients with glioblastoma multiforme. 1062 53

The lactate dehydrogenase (LDH) assay was addressed for its sensitivity, disturbances by foaming, and cell number and size. Cells were from a U-251 MG grade IV human glioblastoma brain tumor cell line used in 100-microl well volumes. Cells were counted by microscopy and Coulter counting; assays were LDH or trypan blue. The results indicate increased 490 nm signals (level, variance) by using phenol red or by increasing fetal bovine serum from 5% to 10%. The data also indicate that defoaming results in reduced variances ranging from a factor of 2 at 1-3 units of absorption, up to a factor of 4-5 at <1 units of absorption. Coulter counting indicated a decrease in cell volume with increasing end-point cell density, attributed to general shrinking at increasing density. In comparisons, total LDH was considered relative to both cell total volume and cell numbers. The result suggests that total LDH should be regarded as reflecting cell total volume rather than cell numbers. In a comparative Cu exposure test, signals of both LDH and a sodium salt of 4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate (WST-1) decreased with increasing Cu supply, while bromodeoxyuridine signals remained largely unaffected. The data show the differences in responses in cell viability and proliferation, but, above all, indicate that LDH should be expressed on a per cell volume basis rather than per cell, to avoid the problem that mere density effects contribute to signals on compound or metal toxicity.
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PMID:Optimization, application, and interpretation of lactate dehydrogenase measurements in microwell determination of cell number and toxicity. 1643 62

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


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