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)

Inhibitory coupling of receptors to adenylate cyclase previously has been shown to be relatively sensitive to inactivation by alkylation with N-ethylmaleimide (NEM). Modification of the inhibitory guanine nucleotide regulatory protein, Ni, has been proposed to be responsible for this effect. The effects of NEM on GTP-sensitive binding of carbachol to muscarinic cholinergic receptors has been compared in a cell line (1321N1 human astrocytoma cells) in which these receptors stimulate phosphoinositide breakdown and in a cell line (NG108-15 neuroblastoma X glioma cells) in which activation of these receptors results in inhibition of adenylate cyclase. Pretreatment of membrane preparations from 1321N1 cells with NEM resulted in a concentration-dependent decrease in the extent of pertussis toxin-catalysed [32P]ADP-ribosylation of a 41 000 Da protein previously proposed to be the alpha subunit of Ni. Under conditions where 32P-labelling of Ni in 1321N1 membranes was reduced by NEM by 90%, no effect was observed on the extent of guanine nucleotide-sensitive high-affinity binding of carbachol to muscarinic cholinergic receptors. In contrast, treatment of NG108-15 membranes with NEM under the same conditions resulted in complete loss of high-affinity guanine nucleotide sensitive binding of carbachol. These results illustrate another difference between the muscarinic receptor population of these two cell lines, and support the previous proposal that muscarinic receptors of 1321N1 cells couple to a guanine nucleotide regulatory protein that is not Ni.
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PMID:Further evidence that muscarinic cholinergic receptors of 1321N1 astrocytoma cells couple to a guanine nucleotide regulatory protein that is not Ni. 392 72

Chronic etorphine treatment of neuroblastoma X glioma NG108-15 cells results in both an increase in adenylate cyclase activity (upon addition of the opiate antagonist naloxone) as well as an homologous desensitization of the opiate receptor. The continued ability of opiate agonists to regulate adenylate cyclase activity following opiate receptor desensitization can be understood by proposing that the catalytic subunit of adenylate cyclase in NG108-15 cells is under tonic regulation by both guanine nucleotide regulatory (Ni) and stimulatory (NS) components. Inactivation of Ni by pertussis toxin (PT) treatment resulted in elevated adenylate cyclase activities comparable to those observed in control cells following chronic opiate treatment. This increased enzymatic activity could not be further induced by PT treatment of cells exposed to opiate previously. In addition, procedures that prevented receptor-mediated activation of NS, i.e., treatment with NaF or desensitization of the stimulatory receptors (prostaglandin E1, adenosine) eliminated the increase in adenylate cyclase activity induced by naloxone following chronic opiate exposure. Hence, the increase in enzymatic activity observed following chronic opiate treatment may be due to a loss in tonic inhibitory regulation of adenylate cyclase mediated through Ni resulting in the unimpeded expression of NS activity. This tonic inhibition of adenylate cyclase activity is one of the multiple mechanisms by which Ni regulates adenylate cyclase in this cell line.
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PMID:Involvement of both inhibitory and stimulatory guanine nucleotide binding proteins in the expression of chronic opiate regulation of adenylate cyclase activity in NG108-15 cells. 393 Jun 63

It has been proposed elsewhere [Meeker, R.B. & Harden, T. K. (1982) Mol. Pharmacol. 22, 310-319] that muscarinic cholinergic receptor-mediated attenuation of cAMP accumulation occurs through activation of phosphodiesterase in 1321N1 human astrocytoma cells. Pertussis toxin, which ADP-ribosylates the guanine nucleotide regulatory protein involved in receptor-mediated inhibition of adenylate cyclase (Ni), has been utilized to further differentiate between the mechanism of cholinergic regulation of cAMP metabolism in 1321N1 cells and the mechanism involving inhibition of adenylate cyclase in other tissues. Muscarinic receptor-mediated regulation of cAMP accumulation in NG108-15 neuroblastoma-glioma cells occurs through inhibition of adenylate cyclase. Pretreatment of these cells with pertussis toxin completely blocked the capacity of carbachol to attenuate cAMP accumulation. In contrast, concentrations of pertussis toxin two to three orders of magnitude higher than those effective in NG108-15 cells had no effect on muscarinic receptor-mediated attentuation of cAMP accumulation in 1321N1 cells. In addition, no effect of pertussis toxin was observed either on the control rate or the carbachol-stimulated rate of cAMP degradation measured directly in intact 1321N1 cells. A 41,000 Mr protein previously proposed to be the alpha subunit of Ni was labeled during incubation of a plasma membrane fraction from 1321N1 cells with [32P]NAD and pertussis toxin. Pertussis toxin is apparently active in 1321N1 cells, since this protein substrate was not labeled in plasma membrane preparations from cells previously incubated with toxin. Functional activity of Ni was demonstrated by the observation that guanosine 5'-[gamma-thio]triphosphate- and GTP-mediated inhibition of forskolin-stimulated adenylate cyclase activity occurred in cell-free preparations from 1321N1 cells. The inhibitory activity of these guanine nucleotides was lost in membrane preparations from pertussis toxin-treated cells. The data suggest that adenylate cyclase is not involved in cholinergic action in 1321N1 cells and, furthermore, Ni is not involved in muscarinic receptor-mediated activation of phosphodiesterase in these cells. Thus, pertussis toxin can be used to differentiate between two mechanisms of cholinergic regulation of cAMP metabolism.
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PMID:Pertussis toxin differentiates between two mechanisms of attenuation of cyclic AMP accumulation by muscarinic cholinergic receptors. 609 Nov 3

In neuroblastoma-glioma (NG108-15) hybrid cells, opiates inhibit adenylate cyclase and stimulate a low Km GTPase. It has been postulated that the stimulation of GTPase plays a role in opiate inhibition of adenylate cyclase (Koski, G., and Klee, W. A. (1981) Proc. Natl. Acad. Sci. U.S.A. 78, 4185-4189). Treatment of NG108-15 cells with pertussis toxin attenuates receptor-mediated inhibition of adenylate cyclase. The toxin acts by catalyzing the ADP-ribosylation of a 41,000-dalton substrate believed to be a part of the receptor-adenylate cyclase complex. We have found that toxin treatment of NG108-15 results in inhibition of the opiate-stimulated GTPase. The concentration of toxin required for inhibition of this GTPase was similar to that needed for both attenuation of opiate inhibition of adenylate cyclase and ADP ribosylation of the 41,000-dalton substrate. Inhibition of the opiate-induced GTPase by pertussis toxin in isolated membranes required NAD, consistent with the hypothesis that this effect of the toxin resulted from ADP ribosylation of a protein component of the system. Since the opiate-stimulated GTPase is believed to play a role in the receptor-mediated decrease in adenylate cyclase activity, inhibition of this GTPase may be an important part of the mechanism by which the toxin interferes with opiate action on adenylate cyclase.
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PMID:Pertussis toxin inhibits enkephalin stimulation of GTPase of NG108-15 cells. 613 91

Pertussis toxin (islet-activating protein) activates adenylate cyclase in susceptible cells by ADP-ribosylating an inhibitory component of the cyclase system. This toxin, assayed in a cell-free system in the presence of high concentrations of thiol, catalyzed the hydrolysis of NAD to ADP-ribose and nicotinamide. This NAD glycohydrolase activity co-chromatographed on Sephacryl G-200 in 6.5 M urea, pH 3.2, 0.1 M glycine with the ADP-ribosyltransferase activity of the toxin, as monitored by the transfer of [32P]ADP-ribose from [32P]NAD to a 41,000-Da protein in NG108-15 neuroblastoma X glioma hybrid cells. In the absence of thiol, the native holotoxin was enzymatically inactive. Following addition of 250 mM dithiothreitol to the assay, maximal enzymatic activity was evident after a delay of approximately 1 h; with 20 mM thiol, the delay was longer. The Km for NAD with the fully activated enzyme was 25 microM; the Km did not appear to vary with the extent of activation. Thiol was necessary in a cell-free system to demonstrate NAD glycohydrolase activity. When extensively washed membranes were used as a source of 41,000-Da substrate, thiol was necessary to observe ADP-ribosylation in some cases (human erythrocytes) and significantly stimulated activity in others (NG108-15 cells). In contrast to the bacterial toxins choleragen and Escherichia coli heat-labile enterotoxin that ADP-ribosylate stimulatory components of the cyclase system, pertussis toxin did not transfer ADP-ribose to low molecular weight guanidino compounds, such as arginine or agmatine.
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PMID:Activation by thiol of the latent NAD glycohydrolase and ADP-ribosyltransferase activities of Bordetella pertussis toxin (islet-activating protein). 631 27

Adenylate cyclase in NG108-15 (neuroblastoma X glioma hybrid) cells is responsive to both stimulatory and inhibitory ligands. Bordetella pertussis toxin (PT) catalyzes the ADP-ribosylation of a 41,000-Da peptide believed to be a subunit of the putative guanyl nucleotide-binding protein (Gi) involved in cyclase inhibition and abolishes inhibitory effects of opiate agonists. In studying the effects of PT on opiate receptors, we found that [3H]enkephalinamide binding was reduced by approximately 90% in membranes prepared from cells incubated with PT compared to control membranes. Agonist affinity, assessed by enkephalinamide competition for [3H]diprenorphine-binding sites, was markedly reduced in cells incubated with PT. Furthermore, inhibition by guanylylimidodiphosphate of ligand binding to opiate receptors was reduced following treatment with PT. The number of opiate receptors assessed by [3H]diprenorphine binding was unaltered by PT. These data are consistent with the hypothesis that PT-catalyzed ADP-ribosylation impairs the interaction of Gi with the inhibitory receptor-ligand complex, effectively uncoupling the inhibitory receptor from Gi and the cyclase catalytic unit.
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PMID:ADP-ribosylation of adenylate cyclase by pertussis toxin. Effects on inhibitory agonist binding. 631 76

Neuroblastoma X glioma hybrid cells NG108-15 were treated with a toxin derived from Bordetella pertussis. As compared to control cells grown in the absence of toxin, the inhibitory effects of opioid agonists upon cAMP formation were dose-dependently impaired by a non-competitive mechanism. Radioligand binding studies revealed that opioid agonist binding was dramatically reduced in toxin-treated membranes when tested in the presence of Na+/Mg++/GMP-PNP. Further, the potencies of guanine nucleotides to decrease opioid agonist binding were differentially modulated. These studies may facilitate our understanding of the mechanisms responsible for acute and chronic opiate effects.
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PMID:Pertussis toxin decreases opiate receptor binding and adenylate inhibition in a neuroblastoma x glioma hybrid cell line. 631 65

Although the neurotoxicity of organophosphorus compounds is generally attributed to inhibition of acetylcholinesterase, recent reports have indicated that direct interactions with muscarinic receptors and signal transduction may be an additional mechanism of neurotoxicity. We have previously shown that the organophosphorus insecticide O,O-diethyl O-3,5,6-trichloro-2-pyridinyl phosphorothioate (chlorpyrifos) binds directly to muscarinic receptors and inhibits adenylate cyclase of rat striatum. We have further pursued those results in this study by investigating the effect of chlorpyrifos oxon in NG108-15 neuroblastoma-glioma cells and Chinese hamster ovary cells transfected with cDNA for human m2 or m4 muscarinic receptor subtypes. At millimolar concentrations, chlorpyrifos oxon inhibited [3H]QNB binding in all cell lines. Likewise, [3H]CD binding was inhibited in NG108-15 and CHO-Hm2 cells. When the effect of chlorpyrifos oxon on adenylate cyclase was examined, the oxon was found to inhibit adenylate cyclase at millimolar concentrations. Though this effect on cyclase required greater concentrations of oxon than the comparable effect in striatal cells, it displayed the common characteristic of being atropine-insensitive, suggesting that the effect on cyclase was not muscarinic receptor dependent. The inhibition of adenylate cyclase produced by chlorpyrifos oxon was not eliminated in pertussis toxin treated cells, lending further support to the idea that it is not a receptor-mediated event, and suggesting a potential direct interaction of chlorpyrifos oxon with the adenylate cyclase molecule.
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PMID:In vitro effect of chlorpyrifos oxon on muscarinic receptors and adenylate cyclase. 756 87

1. The effects of chronic in vitro administration of amitriptyline, a tricyclic antidepressant, on 5-hydroxytryptamine (5-HT) receptor-mediated adenylyl cyclase activity was studied in the neuroblastoma x glioma hybrid cell line, NG 108-15. 2. Treatment of NG 108-15 cells with 8 microM amitriptyline for 3 days increased forskolin-stimulated (0.1 microM) adenosine 3':5'-cyclic monophosphate (cyclic AMP) accumulation. Addition of 5-HT (0.1-100 microM) increased forskolin-stimulated cyclic AMP accumulation in amitriptyline-treated cells in a concentration-dependent manner. However, 5-HT did not affect forskolin-stimulated cyclic AMP accumulation in untreated cells. 3. The 5-HT4 receptor agonist, 5-methoxytryptamine, significantly enhanced forskolin-stimulated cyclic AMP accumulation in amitriptyline-treated cells. In contrast, amitriptyline treatment failed to modify 8-hydroxy-2-(di-n-propylamine) tetralin-induced inhibition of forskolin-stimulated cyclic AMP accumulation. 4. Pretreatment of cells with pertussis toxin did not affect the 5-HT-induced enhancement of cyclic AMP accumulation. 5. The 5-HT-induced enhancement of cyclic AMP accumulation in amitriptyline-treated cells was attenuated by the 5-HT4 receptor antagonists, GR 113808 and ICS 205-930, with relatively low potency. However, spiperone, SCH 23390, and pindolol were completely ineffective against this 5-HT-induced enhancement. 6. Chronic treatment with amitriptyline did not modify the cyclic AMP production stimulated by prostaglandin E1 or cholera toxin. This treatment also had no effect on GTP gamma S-, NaF-, and Mn(2+)-stimulated cyclic AMP accumulation in isolated cell membranes. 7. Chronic treatment with the 5-HT receptor antagonists, pindolol or ICS 205-930, did not inhibit the 5-HT-induced enhancement of cyclic AMP accumulation.8. Chronic treatment with other antidepressant drugs, imipramine, mianserin or paroxetine, elicited the 5-HT-induced enhancement of cyclic AMP accumulation.9. Taken together, these results suggest that chronic amitriptyline treatment of NG 108-15 cells causes 5-HT to enhance forskolin-stimulated cyclic AMP accumulation by enhancing 5-HT receptor-mediated stimulation of adenylyl cyclase and not by reducing 5-HT-mediated inhibition of adenylyl cyclase. The 5-HT-induced enhancement of cyclic AMP accumulation in amitriptyline-treated cells may result from changes at the level of the 5-HT receptor rather than at the level of G, proteins or adenylyl cyclase. It is unlikely that this enhancement of cyclic AMP accumulation is caused by long-term antagonism of the 5-HT receptor by amitriptyline.
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PMID:Enhancement of cyclic AMP accumulation mediated by 5-HT after chronic amitriptyline treatment in NG 108-15 cells. 762 Jul 19

Voltage-dependent Ca2+ currents were measured in NG108-15 neuroblastoma x glioma hybrid cells transformed to express the rat mu-opioid receptor by the whole-cell configuration of the patch-clamp technique with Ba2+ as charge carrier. A mu-opioid receptor-selective agonist, [D-Ala2,N-Me-Phe4,Gly5-ol]-enkephalin caused significant inhibition of voltage-dependent Ca2+ currents in mu-receptor-transformed NG108-15 cells but not in nontransfected or vector-transformed control cells. On the other hand, a delta-opioid receptor-selective agonist, [D-penicillamine2,D-penicillamine5]enkephalin, induced inhibition of voltage-dependent Ca2+ currents in both control and mu-receptor-transformed cells, which is mediated by the delta-opioid receptor expressed endogenously in NG108-15 cells. The inhibition of voltage-dependent Ca2+ currents induced by [D-Ala2,N-Me-Phe4,Gly5-ol]enkephalin [D-penicillamine2,D-penicillamine5]enkephalin was reduced by pretreatment of the cells with pertussis toxin or omega-contoxin GVIA. These results indicate that the mu-opioid receptor expressed from cDNA functionally couples with omega-contoxin-sensitive N-type Ca2+ channels through the action of pertussis toxin-sensitive G proteins in NG108-15 cells.
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PMID:Coupling of the cloned mu-opioid receptor with the omega-conotoxin-sensitive Ca2+ current in NG108-15 cells. 764 19


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