Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027819 (neuroblastoma)
 27,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The resistance of cultured mouse neuroblastoma cells, primary cultures of rat cerebellar neurons, and rat brain astrocytes to a block of aerobic metabolism was studied. Parameters such as lactate production and ATP content were measured in the presence of antimycin A and under various conditions of glucose, oxygen, and serum supply. The following conclusions can be drawn: (1) All cell types studied were characterized by an active production of lactate; (2) Incubation of the various cell types in the absence of glucose at normal oxygen tension did not affect ATP levels; (3) Respiration blocked by antimycin led to a Pasteur effect; (4) Neuroblastoma cells, but not the other cell types, were fully resistant to inhibition of respiration provided that sufficient glucose was supplied; (5) In the absence of glucose no stores of energy or utilizable substrate were present in the cell types studied when respiration was blocked; (6) In the presence of fetal calf serum anoxic neurons showed irreversible signs of degeneration.
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PMID:Effects of antimycin, glucose deprivation, and serum on cultures of neurons, astrocytes, and neuroblastoma cells. 396 24

eIF-2 purified from neuroblastoma cells consists of three subunits, which appear to be of molecular weight identical to those of the subunits of rabbit reticulocyte eIF-2. A protein fraction has been isolated from neuroblastoma cells with characteristics similar to eRF from reticulocytes: stimulation of amino acid incorporation in a hemin-deprived reticulocyte lysate, the removal of GDP from eIF-2-GDP complexes, a 4-5-fold stimulatory effect in a two-step reaction measuring 40 S preinitiation complex formation and a 3-3.5-fold stimulation in the methionyl-puromycin synthesis. In the methionyl-puromycin-synthesizing system phosphorylated eIF-2 is not responsive to the addition of this fraction from neuroblastoma cells. The protein fraction contains eRF which seems to be similar to the eRF isolated from Ehrlich ascites tumor cells and somewhat distinct from the reticulocyte factor. Incubation of neuroblastoma cell lysate in the presence of [gamma-32P]ATP results in the phosphorylation of a protein of Mr 36 000, migrating on SDS-polyacrylamide gels to the position of eIF-2 alpha. This protein is also phosphorylated in vitro by HRI from reticulocytes. These results may reflect a common underlying principle for the quantitative regulation of protein synthesis in eukaryotic cells.
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PMID:Regulation of protein synthesis in eukaryotes. Eukaryotic initiation factor eIF-2 and eukaryotic recycling factor eRF from neuroblastoma cells. 401 22

The energy metabolism of living tumors in rats and hamsters were investigated by obtaining in vivo 31P-NMR spectra, and the effects of chemotherapy on tumors were evaluated by observing the changes of these spectra. Tumor cells of rat glioma, human glioblastoma and human neuroblastoma were inoculated subcutaneously in the lumbar region of the animals. After the tumor grew to over 1.5 cm in diameter, in vivo 31P-NMR spectrum data was obtained selectively from the tumor with a TMR-32 spectrometer (Oxford Research Systems, U.K.). Several peaks (ATP, inorganic phosphate (Pi), phosphodiesters and phosphomonoesters (PME) were observed in the tumors. The heights of these peaks varied widely corresponding to the tumor growth. However, the spectrum pattern of each tumor in an active stage was found to be essentially the same regardless of histological type or tumor origin. The phosphocreatine (PCr) peak was small, ATP and PME peaks were large and tissue pH calculated from the chemical shift of Pi was low in each tumor group. After intravenous injection of a large dose of a chemotherapeutic agent, ATP peaks decreased and the Pi peak increased gradually, resulting in a dominant Pi peak pattern after several hours in all groups. With lower drug doses, spectrum changes were temporarily seen in the tumors. These findings indicated that drugs with a high dose have a selective and a direct action on the energy metabolism of tumor tissues. In vivo 31P-NMR spectra measurement is very valuable not only to investigate the energy metabolism in tumor tissue but also to evaluate the effects of chemotherapy on the tumor.
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PMID:Observations of energy metabolism in neuroectodermal tumors using in vivo 31P-NMR. 403 75

Specific, GTP hydrolysis catalyzed by membranes prepared from neuroblastoma--glioma (NG108-15) hybrid cells can be measured in the presence of adenosine-5'-[beta, gamma-imido] triphosphate (p[NH]ppA), ATP, and a nucleotide triphosphate-regenerating system. Opiates and opioid peptides stimulate low Km GTP hydrolysis when measured in the presence of Na+ and Mg2+. Opiate stimulation is rapid, stereospecific, and reserved by the antagonist naloxone. Potencies of opiates as stimulators of GTP hydrolysis and as inhibitors of adenylate cyclase are closely correlated. Agents that stimulate adenylate cyclase, including prostaglandin E1, 2-Cl-adenosine, secretin, and NaF, have little or no effect upon the rate of GTP hydrolysis. Opiates have no effect upon either adenylate cyclase or GTPase activity in membranes prepared from C6-BU1 glioma cells, which lack opiate receptors. In view of the pivotal role of GTP in the activation of adenylate cyclase, we conclude that receptor-mediated stimulation of GTP hydrolysis is the mechanism by which opiates and other inhibitory hormones lower adenylate cyclase activity in NG108-15 cell membranes.
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PMID:Opiates inhibit adenylate cyclase by stimulating GTP hydrolysis. 611 72

Increased intracellular adenosine 3':5'-monophosphate (cAMP) levels and activation of cAMP-dependent protein kinases (ATP:protein phosphotransferase, EC 2.7.1.37) in vivo were correlated in mouse neuroblastoma cells grown in the presence of 1 mM-6N,O2'-dibutyryl 3':5'-monophosphate (Bt2cAMP). The time course for activation showed that cAMP-dependent protein kinases were activated by 30 min. A heat-stable inhibitor protein inhibited a majority of activated cAMP-dependent protein kinase. Activation of cAMP-dependent protein kinase caused additional phosphorylation of proteins when compared with untreated control cells, as demonstrated by endogenous phosphorylation of proteins in vitro using [gamma-32P]ATP and analysis by two-dimensional polyacrylamide gel electrophoresis. The phosphorylation data show selective phosphorylation of specific proteins by cAMP-independent and cAMP-dependent protein kinase. Among the proteins in the postmitochondrial supernatant fraction phosphorylated by cAMP-dependent protein kinases, two proteins with a molecular weight of 43,000 were heavily phosphorylated. It is suggested that phosphorylation of cellular proteins by cAMP-dependent protein kinases might be involved in the cAMP-modulated biochemical changes in neuroblastoma cells.
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PMID:Phosphorylation of endogenous proteins by adenosine 3':5'-monophosphate-dependent protein kinase in mouse neuroblastoma cells. 625 79

Clonidine and several analogues of clonidine are shown to be useful probes for alpha 2-adrenergic receptors in a comparative study of ligand binding and inhibition of adenylate cyclase. The alpha-adrenergic properties of a new potential probe, N-(4-hydroxyphenacetyl)-4-aminoclonidine hydrochloride, are described. [3H]Clonidine binds to alpha-receptors of NG108-15 neuroblastoma X glioma hybrid cell membranes with Kd values of 1.7 and 33 nM for putative high-affinity and low-affinity sites, respectively. p-Aminoclonidine and hydroxyphenacetyl aminoclonidine displace [3H]clonidine from the high-affinity sites with Kd values of 2.3 and 5.8 nM, respectively. Rat brain alpha 2-receptors also exhibit high affinity toward clonidine, p-aminoclonidine, and hydroxyphenacetyl aminoclonidine, as determined by displacement of specifically bound [3H]clonidine. Clonidine, p-amino-clonidine, and hydroxyphenacetyl aminoclonidine elicit modest inhibition (up to 24%) of NG108-125 adenylate cyclase by interaction with alpha 2-receptors (Kd,app 300, 30, and 130 nM, respectively); these compounds also partially reverse the inhibition elicited by (--)-norepinephrine. Components of the adenylate cyclase assay mixture, particularly ATP, GTP, sodium ions, and a nucleoside-triphosphate-regenerating system, decrease the high-affinity [3H]clonidine binding to NG108-15 membranes; in the presence of these components, alpha-receptors possess only low affinity (Kd 43 nM) for [3H]clonidine. The results are consistent with the concept that certain components required for the receptor-mediated inhibition of adenylate cyclase convert alpha 2-receptors from a high-affinity inactive state to a low-affinity active state.
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PMID:Interaction of clonidine and clonidine analogues with alpha-adrenergic receptors of neuroblastoma X glioma hybrid cells and rat brain: comparison of ligand binding with inhibition of adenylate cyclase. 626 Apr 85

Functional and optimal activities of the (Na+-K+)ATPase, as determined by ouabain-sensitive K+ influx in intact cells and ATP hydrolysis in cell homogenates respectively, have been measured during the cell cycle of neuroblastoma (clone Neuro-2A) cells. The cells were synchronized by selective detachment of mitotic cells. The ouabain-sensitive K+ influx decreased more than fourfold from 1.62 +/- 0.11 nmoles/min/10(6) cells to 0.36 +/- 0.25 nmoles/min/10(6) cells on passing from mitosis to early G1 phase. On entry into S phase a transient sixfold increase to 2.07 +/- 0.30 nmoles/min/10(6) cells was observed, followed by a rapid decline, after which the active K+ influx rose again steadily from 1.03 +/- 0.25 nmoles/min/10(6) cells in early S phase to 2.10 +/- 0.92 nmoles/min/10(6) cells just prior to the next mitosis. The ouabain-insensitive component rose linearly through the cycle in the same manner as the protein content/cell. Combining total K+ influx values with efflux data obtained previously showed that net loss of K+ occurred with transition from mitosis to G1 phase while net accumulation occurred with entry into S. Throughout mid-S phase net K+ flux was virtually zero, but a large net influx occurred again just before the next mitosis. The (Na+-K+)ATPase activity measured in cell homogenates decreased rapidly from mitosis to G1 phase and increased steadily throughout S phase, but the transient activation on entry into S phase was not observed. Complete inhibition of the (Na+-K+)ATPase mediated K+ influx by ouabain (5 mM) prevents the cells from entering S phase, while partial inhibition by lower concentrations of ouabain (0.2 and 0.5 mM; km = 0.17 mM) causes partial blockage in G1 and, to a lesser extent, a reduced rate of progression through the rest of the cell cycle. We conclude that the transient increase in (Na+-K+)ATPase mediated K+ influx at the G1/S transition is a prerequisite for entry into S phase, while maintenance of adequate levels of K+ influx is necessary for normal rate of progression through the rest of the cell cycle.
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PMID:Modulation of functional and optimal (Na+-K+)ATPase activity during the cell cycle of neuroblastoma cells. 626 Aug 24

The sequence of early events which follow the administration of E coli lipopolysaccharide (LPS) to cultured mouse neuroblastoma (C-1300) cells was investigated. Emphasis was placed on cellular energy metabolism in order to establish whether or not an energy failure occurred and whether it was a primary or a secondary effect. Exposure of cultured neuroblastoma cells to LPS produced rapid changes in the regulatory parameters of energy metabolism, an oxidation of intramitochondrial pyridine nucleotides, and a decline in cellular [ATP]/[ADP] [Pi], which were followed by alterations in mitochondrial morphology. In spite of the changes in individual parameters at early stages of exposure to LPS, the cellular energy producing systems remained tightly controlled and the rate of ATP synthesis was maintained at a constant and undiminished level. This allowed the cells to preserve their ionic gradients as manifested by high intracellular [K+] and unaltered transmembrane electrical and pH gradients. These early changes in mitochondrial metabolism were not accompanied by detectable leakage of mitochondrial matrix enzymes into the cytosol, which indicated that mitochondrial membrane remained intact. After longer exposure to LPS, the rate of ATP synthesis declined, the mitochondrial membrane became permeable to high molecular weight substances (matrix enzymes), and intracellular [K+] began to decrease (K+ leakage). It was concluded that responses of mitochondrial metabolism are one of the early events in endotoxemia.
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PMID:Early cellular responses in vitro to endotoxin administration. 626 76

Morphological changes were extensive following infection of murine neuroblastoma N-18 cells with a temperature-sensitive (ts) mutant of vesicular stomatitis virus (VSV), G31 (complementation group III), and incubation at 39 degrees C, a non-permissive condition for virion maturation. Incubation for 24 h after infection resulted in extensive morphological degeneration of mitochondria with over 80% from that in uninfected cells. Janus green B supravital staining, was reduced by 81% from that in uninfected cells. Cellular ATP levels were reduced by 50% 12 h after infection. Mitochondrial degeneration still occurred in infected cells after the inactivation of lysosomes with chloroquine. Extensive cell fusion and cytoplasmic vacuole formation also occurred during the non-permissive infection with ts G31. Loss of plasma membrane integrity was not the cause of vacuole formation since 90% of the cells were able to exclude trypan blue 24 h after infection, nor were the vacuoles the result of inactivation of the mitochondria since cyanide-poisoned cells did not form vacuoles. The cytopathic alterations observed in N-18 cells during the non-permissive infection of N-18 cells with ts G31 did not occur during the non-permissive infection of N-18 cells with ts G11 (I), ts G41 (IV), or u.v.-inactivated ts G31. However, the non-permissive infection with ts O45 (V) led to mitochondrial degeneration and cytoplasmic vacuole formation, but no cell fusion occurred. These results are discussed in light of the ultrastructural features previously observed in the central nervous system of mice infected with ts G31 and cells in culture infected with wild-type VSV.
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PMID:Cytopathic effects in mouse neuroblastoma cells during a non-permissive infection with a mutant of vesicular stomatitis virus. 627 Feb 68

The effect of cerebroside sulfate, phosphatidylserine, and other phospholipids on opiate receptor function in neuroblastoma N18TG2 cells was studied by incorporation of lipids into the membrane bilayer of viable cells. A concentration- and time-dependent incorporation of sulfatide by N18TG2 cells was observed. The incorporated lipid was not metabolized during the incubation period of up to 48 hr at 37 degrees. Optimal conditions for lipid incorporation were determined to be 4 days after the cell seeding and in 1% fetal calf serum. The incorporated lipid was established to be associated with the plasma membrane fraction of the crude cell homogenate. Furthermore, increases in Vmax but not Km values of the adenylate cyclase for Mg2+, ATP, and prostaglandin E1 were observed in neuroblastoma N18TG2 cells exposed to cerebroside sulfate for 4--6 hr. The incorporation of cerebroside sulfate or phosphatidylserine by N18TG2 cells did not increase the number of opiate binding sites in this cell line as determined by [3H]naloxone, [3H]etorphine, or 3H-labeled D-Ala2-Met5-enkephalinamide binding. Although there was an increase in the affinity of [3H]naloxone binding, linear correlation between the amount of cerebroside sulfate incorporated and the quantity of binding increase was not observed. However, augmentation of both the potencies and the efficacies (maximal inhibitory level) of morphine and enkephalin to regulate adenylate cyclase activity was observed after sulfatide incorporation. At the maximal concentration of cerebroside sulfate used (67 microM) the opiate receptor activity in N18TG2 cells approached that of NG108-15 cells. Identical treatment of N18TG2 cells with cerebroside or psychosine sulfate did not produce any potentiation of the opiate inhibition of adenylate cyclase. Of all of the phospholipids tested--phosphatidylserine, phosphatidylinositol, and phosphatidylcholine--only phosphatidylcholine produced a potentiation of the opiate effect. Both synthetic dipalmitoyl phosphatidylcholine or brain phosphatidylcholine could elicit the potentiation.
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PMID:Potentiation of opiate action in neuroblastoma N18TG2 cells by lipid incorporation. 628 74


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