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 F11 cell line is a fusion product of cells of mouse neuroblastoma cell line N18TG-2 with embryonic rat dorsal-root ganglion (DRG) neurons. Previous biochemical results suggest that they express mu- and delta-opioid receptors that are negatively coupled to adenylate cyclase. The present study provides direct agonist-binding and electrophysiologic evidence of mu and delta, but not kappa, receptor expression in F11 cells. Radioligand binding assays show that F11 cell membranes bind the mu- and delta-opioid receptor agonists, DAGO and DPDPE with Kd = 4.5 and 4.9 nM and Bmax = 111 and 195 fmol/mg, respectively. Tight-seal patch-clamp recordings of F11 cells after several days in a differentiating culture medium (low serum, cyclic AMP and nerve growth factor) showed that: (i) the outward K+ current during pulsed depolarization in most of these cells was increased by either DAGO or DPDPE, but none were responsive to both opioids or to the kappa-opioid receptor agonist, U-50,488H. The response was blocked by relevant receptor antagonists, naloxone, beta-funaltrexamine or naltrindole; (ii) cells without processes responded neither to DAGO nor to DPDPE; (iii) treatment with pertussis toxin blocked all opioid-induced increases in outward K+ current. The opioid-induced increase in voltage-dependent membrane K+ current in F11 cells resembles the inhibitory effect elicited by mu- and delta-opioid agonists in primary cultures of mouse DRG neurons.
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PMID:F11 neuroblastoma x DRG neuron hybrid cells express inhibitory mu- and delta-opioid receptors which increase voltage-dependent K+ currents upon activation. 133 Feb 16

Low level, chronic exposure (0.1 nM, 24 hrs) to the organophosphate paraoxon significantly inhibits N-[3H]methylscopolamine ([3H]NMS) binding to muscarinic receptors in a noncompetitive manner in the SK-N-SH neuroblastoma cell line. The effect of paraoxon on muscarinic receptor-mediated phosphoinositide hydrolysis was also investigated. At 0.1 nM, paraoxon caused a time-dependent increase in the accumulation of inositol phosphates, while the classical muscarinic receptor agonist carbachol was virtually ineffective at low concentrations. In contrast, carbachol-induced increases in phosphoinositide hydrolysis at higher concentrations (1 mM) were markedly larger (five-fold) than the increases induced by PX. Approximately 50% of the maximal increase in the accumulation of inositol phosphates due to paraoxon treatment was antagonized by saturating concentrations of muscarinic receptor antagonists, while the response to carbachol was completely antagonized. In addition, chronic treatment (24 hrs) of SK-N-SH cells with pertussis toxin blocked 75% of the stimulatory effects of carbachol, but inhibited only 38% of the paraoxon-induced response. Neomycin, a phospholipase C inhibitor, completely blocked both the paraoxon and carbachol-induced stimulation of phosphoinositide hydrolysis. The results suggest that paraoxon can modulate signal transduction by indirect activation of muscarinic receptors as well as by acting at a distal site along the pathway.
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PMID:Organophosphate-induced alterations in muscarinic receptor binding and phosphoinositide hydrolysis in the human SK-N-SH cell line. 133 18

High-threshold (HVA) Ca2+ channels of human neuroblastoma IMR32 cells were effectively inhibited by noradrenaline. At potentials between -20 mV and +10 mV, micromolar concentrations of noradrenaline induced a 50%-70% depression of HVA Ba2+ currents and a prolongation of their activation kinetics. Both effects were relieved at more positive voltages or by applying strong conditioning pre-pulses (facilitation). Facilitation restored the rapid activation of HVA channels and recruited about 80% of the noradrenaline-inhibited channels at rest. Re-inhibition of Ca2+ channels after facilitation was slow (tau r 36-45 ms) and voltage-independent between -30 mV and -90 mV. The inhibitory action of noradrenaline was dose-dependent (IC50 = 84 nM), mediated by alpha 2-adrenergic receptors and selective for omega-conotoxin-sensitive Ca2+ channels, which represent the majority of HVA channels expressed by IMR32 cells. The action of noradrenaline was mimicked by intracellular applications of GTP[gamma S] and prevented by GDP[beta S] or by pre-incubation with pertussis toxin. The time course of noradrenaline inhibition measured during fast application (onset) and wash-out (offset) of the drug were independent of saturating agonist concentrations (10-50 microM) and developed with mean time constants of 0.56 s (tau on) and 3.6 s (tau off) respectively. The data could be simulated by a kinetic model in which a G protein is assumed to modify directly the voltage-dependent gating of Ca2+ channels. Noradrenaline-modified channels are mostly inhibited at rest and can be recruited in a steep voltage-dependent manner with increasing voltages.
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PMID:Voltage-dependent noradrenergic modulation of omega-conotoxin-sensitive Ca2+ channels in human neuroblastoma IMR32 cells. 133 78

The affinity cross-linking of the delta-opioid receptor in neuroblastoma x glioma NG108-15 cells was undertaken using (3-[125I]iodotyrosyl27)human-beta-endorphin ([125I]beta-endorphin) and disuccinimidyl suberate (DSS) or bis(sulfosuccinimidyl) suberate (BS3) in order to estimate molecular size. Following sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis, two radioactive bands were observed. Labeling of a major band of 29 kDa diminished in the presence of unlabeled selective delta-opioid agonist, [D-Pen2,D-Pen5]enkephalin (DPDPE), in a concentration-dependent manner, while labeling of a minor band of 58 kDa was hardly affected. The labeling intensity of the 29 kDa band decreased by addition of guanosine 5'-(3-o-thio)triphosphate (GTP gamma S) or by pretreatment of cells with pertussis toxin. These results, taking the molecular weight of covalently bound beta-endorphin (3.6 kDa) into consideration, suggest that the delta-opioid receptor in NG108-15 cell membrane is a 25 kDa protein which is coupled to pertussis toxin-sensitive guanosine triphosphate-binding proteins (G-proteins).
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PMID:Affinity cross-linked delta-opioid receptor in NG108-15 cells is low molecular weight (25 kDa) and coupled to GTP-binding proteins. 133 16

A study of the intracellular Ca2+ ([Ca2+]i) response of differentiated neuroblastoma x glioma hybrid cells (NG108-15 cell) to enkephalin (EK) was carried out by fura-2 video-imaging. EK alone did not influence [Ca2+]i in single cells. The opioid did, however, induce a marked [Ca2+]i rise, when the cells were incubated with bradykinin (BK) prior to the EK treatment. Such BK-assisted stimulation of the differentiated hybridoma cells by EK was completely abolished by pertussis toxin treatment. These results suggest that in single NG108-15 cells, EK induces Ca2+ mobilization which is assisted by cross-talk between the EK and BK receptor systems via a pertussis toxin-sensitive G protein.
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PMID:Enkephalin induces Ca2+ mobilization in single cells of bradykinin-sensitized differentiated neuroblastoma hybridoma (NG108-15) cells. 133 52

M3 muscarinic receptors expressed on SH-SY5Y human neuroblastoma cells are linked to phosphoinositide turnover and rises in [Ca2+]i. The rise in [Ca2+]i is biphasic with the peak phase being due to release from an intracellular Ins(1,4,5)P3-sensitive site and the plateau phase being due to Ca2+ entry across the plasma membrane. Ca2+ entry does not appear to involve voltage sensitive Ca2+ channels, a pertussis toxin sensitive G-protein-operated Ca2+ channel or Ins(1,4,5)P3/Ins(1,3,4,5)P4-operated Ca2+ channel. We suggest that carbachol-stimulated Ca2+ entry in SH-SY5Y human neuroblastoma cells occurs via receptor operated Ca2+ channels and through capacitive refilling.
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PMID:Carbachol-stimulated calcium entry in SH-SY5Y human neuroblastoma cells: which route? 134 98

To better understand opioid binding parameters found in situ, binding studies were conducted to mu-opioid receptors on intact SH-SY5Y neuroblastoma cells and compared with binding to SH-SY5Y membrane and guinea pig brain membrane preparations. The mu-selective peptide antagonist [3H]D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2 (CTOP) was used for the binding studies. The fact that CTOP is an antagonist and hydrophilic is important for binding to be achieved using intact cells. In intact cells, using a physiological buffer, there appears to be only a low affinity "agonist" conformation of the receptor. This is in contrast to binding in either brain or SH-SY5Y membranes in Tris buffer, in which high-affinity agonist binding was prevalent. As expected from the binding profiles, pertussis toxin treatment of cells has no effect on binding to intact cells, but significantly decreases affinity of agonists to cell membranes. In intact cells, binding appears to be to a single site and a single state of the mu receptor. Although in membrane preparations inhibition curves are shallow, with slope factors less than 1.0 for many agonists, on intact cells agonist inhibition curves are very steep, with slope factors slightly greater than 1.0.
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PMID:Comparison of mu opioid receptor binding on intact neuroblastoma cells with guinea pig brain and neuroblastoma cell membranes. 134 68

Bradykinin (BK) induced a transient and pertussis toxin (PT)-insensitive increase in cytosolic Ca2+ ([Ca2+]i) in NG 108-15 neuroblastoma x glioma hybrid cells, whereas leucine-enkephalin (EK), somatostatin, norepinephrine or carbachol showed a weak but PT-sensitive action. When any one of the latter agonists was applied to the cells treated with low doses of BK, however, the level of [Ca2+]i rise caused by the agonist was remarkably increased in a PT-sensitive manner. The decreasing of extracellular Ca2+ only slightly influenced the actions of these agonists. Thus, synergism between a BK receptor and PT-sensitive G-protein-coupled receptors results in marked intracellular Ca2+ mobilization by the latter agonists.
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PMID:Synergism in cytosolic Ca2+ mobilization between bradykinin and agonists for pertussis toxin-sensitive G-protein-coupled receptors in NG 108-15 cells. 134 83

Bordetella pertussis produces a calmodulin-stimulated adenylyl cyclase that invades animal cells and raises intracellular cAMP levels [Confer, D. L., & Eaton, J. W. (1982) Science 217, 948-950; Shattuck, R. L., & Storm, D. R. (1985) Biochemistry 24, 6323-6328]. The mechanism for invasion of animal cells by this enzyme has not been defined, but there is considerable evidence that it does not enter by receptor-mediated endocytosis [Gordon, V. M., Leppla, S. H., & Hewlett, E. L. (1988) Infect. Immun. 56, 1066-1069; Donovan, M. G., & Storm, D. R. (1990) J. Cell. Physiol. 145, 444-449]. In this study, the importance of high-affinity calmodulin (CaM) binding for entry of the enzyme into neuroblastoma cells was evaluated using a mutant enzyme that has significantly lower affinity for calmodulin than the wild-type enzyme. Oligonucleotide-directed site-specific mutagenesis was used to create a point mutant at a critical tryptophan residue (Trp-242) within the proposed CaM binding domain of the B. pertussis adenylyl cyclase. Substitution of Trp-242 with Glu lowered the apparent affinity of the enzyme for calmodulin by 250-fold; however, the maximal enzyme activity in the presence of saturating calmodulin was equivalent to the wild-type enzyme. The Glu-242 mutant adenylyl cyclase was returned to B. pertussis by homologous recombination, and the enzyme produced by this strain was examined for invasion of neuroblastoma cells. Although the mutant enzyme stimulated the production of intracellular cAMP in neuroblastoma cells, the rate of cAMP accumulation was at least 10-fold lower than that caused by the wild-type enzyme.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:High-affinity calmodulin binding is required for the rapid entry of Bordetella pertussis adenylyl cyclase into neuroblastoma cells. 139 Jun 75

Parameters of ligand binding, stimulation of low-Km GTPase, and inhibition of adenylate cyclase were determined in intact human neuroblastoma SH-SY5Y cells and in their isolated membranes, both suspended in identical physiological buffer medium. In cells, the mu-selective opioid agonist [3H]Tyr-D-Ala-Gly(Me)Phe-Gly-ol ([3H]DAMGO) bound to two populations of sites with KD values of 3.9 and 160 nM, with less than 10% of the sites in the high-affinity state. Both sites were also detected at 4 degrees C and were displaced by various opioids, including quaternary naltrexone. The opioid antagonist [3H]naltrexone bound to a single population of sites, and in cells treated with pertussis toxin the biphasic displacement of [3H]naltrexone by DAMGO became monophasic with only low-affinity binding present. The toxin specifically reduced high-affinity agonist binding but had no effect on the binding of [3H]naltrexone. In isolated membranes, both agonist and antagonist bound to a single population of receptor sites with affinities similar to that of the high-affinity binding component in cells. Addition of GTP to membranes reduced the Bmax for [3H]DAMGO by 87% and induced a linear ligand binding component; a low-affinity binding site, however, could not be saturated. Compared with results obtained with membranes suspended in Tris buffer, agonist binding, including both receptor density and affinity, in the physiological medium was attenuated. The results suggest that high-affinity opioid agonist binding represents the ligand-receptor-guanine nucleotide binding protein (G protein) complex present in cells at low density due to modulation by endogenous GTP.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Opioid signal transduction in intact and fragmented SH-SY5Y neural cells. 156 Feb 22


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