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 cleavage of dynorphin and three analogs containing paired basic residues by several proteases was investigated. The cysteine protease of neuroblastoma cells cleaved only the bond between Arg-Arg residues. Submandibular arginyl-endopeptidase, however, cleaved bonds between both Arg-Arg and Arg-Lys residues, and pancreatic trypsin at the carboxyl sides of both arginine and lysine residues. This shows that the cysteine protease is highly specific for paired arginine residues.
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PMID:Dynorphin-degrading cysteine protease is highly specific for paired arginine residues. 134 63

Two dynorphin-degrading cysteine proteases, I and II, were extracted with Triton X-100 from neuroblastoma cell membrane, isolated from accompanying dynorphin-degrading trypsin-like enzyme by affinity chromatography on columns of soybean trypsin inhibitor-immobilized Sepharose and p-mercuribenzoate-Sepharose, and separated by ion-exchange chromatography on diethylaminoethyl (DEAE)-cellulose and TSK gel DEAE-5PW columns. Cysteine protease II was purified further by hydroxyapatite chromatography and gel filtration. The molecular weights of cysteine proteases I and II were estimated to be 100,000 and 70,000, respectively, by gel filtration. Both of the enzymes, were inhibited by p-chloromercuribenzoate, N-ethylmaleimide, and high-molecular-weight kininogen, but not or only slightly inhibited by diisopropylphosphorofluoridate, antipain, leupeptin, E-64, calpain inhibitor, and phosphoramidon. Cysteine protease I cleaved dynorphin(1-17) at the Arg6-Arg7 bond with the optimum pH of 8.0, whereas II cleaved dynorphin(1-17) at the Lys11-Leu12 bond and the Leu12-Lys13 bond with the optimum pH values of 8.0 and 6.0, respectively. These bonds corresponded to those that had been proposed as the initial sites of degradation by neuroblastoma cell membrane. Cysteine protease I was further found to show strict specificity toward the Arg-Arg doublet, when susceptibilities of various peptides containing paired basic residues were examined as substrates for the enzyme.
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PMID:Characterization of cysteine proteases functioning in degradation of dynorphin in neuroblastoma cells: evidence for the presence of a novel enzyme with strict specificity toward paired basic residues. 256 12

There was stereospecific binding of 3H-lofentanil (KD value = 1.53 nM) to membranes of neuroblastoma-glioma NG 108-15 cells which are known to bear high affinity binding sites for enkephalin derivatives (delta-opiate receptor subtype). There was no high affinity specific binding of the mu-opiate specific ligand 3H-sufentanil. The specific binding of 3H-lofentanil to delta-opiate receptor subtype was down-regulated (decrease in Bmax value without change in the KD value) after prolonged incubation of the cells in the presence of leu- and met- enkephalin (0.1 microM). There was no down-regulation of the opiate receptors (3H-lofentanil and 3H-D-ala-D-leu-enkephalin specific binding) after incubation of NG 108-15 cells with drugs from the fentanyl series (alfentanil or sufentanil). In cultured neurones from rat forebrain (15 day old embryos), the 3H-lofentanil binding was specific with high affinity (KD: 0.048 nM) and a slow dissociation rate similar to that in adult rat cortex. Drugs of the fentanyl series (4-anilino-piperidines) were potent displacers whereas agonists of the delta- (enkephalin derivatives), sigma- (phencyclidine, haloperidol, 3-hydroxyphenyl-propylpiperidine) or K- (U 50488) opiate sites had a low affinity (Ki greater than 0.5 microM) for 3H-lofentanil specific binding sites. Since there was also specific binding of 3H-sufentanil, the opiate receptors in cultured neurones seem to be mainly of the mu-subtype and this is consistent with the ontogeny of opiate receptors subtypes. These receptors were down-regulated after incubation in the presence of etorphine, sufentanil and alfentanil but not enkephalin derivatives.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Down-regulation of 3H-lofentanil binding to opiate receptors in different cultured neuronal cells. 256 25

The membrane of mouse neuroblastoma N-18 cells degraded dynorphin-(1-13), dynorphin-(1-17), and Leu-enkephalin. The degradation of the former two peptides was inhibited strongly by N-ethylmaleimide, moderately by diisopropylphosphorofluoridate and phosphoramidon, and slightly by bestatin. When Leu-enkephalin was the substrate, however, the effects of phosphoramidon and bestatin were marked and those of N-ethylmaleimide and diisopropylphosphorofluoridate were negligibly small. Captopril did not affect the degradation of the two dynorphins and Leu-enkephalin, but inhibited the further cleavage of N-terminal fragments generated from dynorphin-(1-13) by the N-ethylmaleimide-sensitive protease. Thus, a cysteine protease and, probably, a serine protease are responsible to the initial fragmentation of the dynorphins.
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PMID:Degradation of dynorphin-(1-13) and dynorphin-(1-17) by the neuroblastoma cell membrane. Evidence for the involvement of a cysteine protease. 287 60

A trypsin-like enzyme has been purified to apparent homogeneity from neuroblastoma cell membranes by a procedure including extraction with Triton X-100, soybean trypsin inhibitor-immobilized Sepharose 4B affinity chromatography, and gel filtration. SDS-polyacrylamide gel electrophoresis under reducing conditions of the purified enzyme gave a single band corresponding to a molecular weight of 28,000. The molecular weight of the enzyme was also estimated to be 32,000 by gel filtration. The pH optimum of the activity was 8.5-9.0. The purified enzyme was inhibited by diisopropylphosphorofluoridate, p-aminobenzamidine, and leupeptin, and moderately by chymostatin, but not, or only scarcely, by bestatin, phosphoramidon, p-chloromercuribenzoate, and N-ethylmaleimide. The substrate subsite specificity of the purified enzyme was broad toward various peptidyl-arginine (or lysine) 4-methylcoumaryl-7-amides, but it cleaved dynorphin(1-17) only at two sites, i.e., between the Arg6-Arg7 and Lys11-Leu12 bonds, both of which correspond to the initial cleavage sites of dynorphin with a membrane preparation of neuroblastoma cells. A trypsin-like enzyme was also purified from a synaptic membrane preparation of rat brain, which shows almost the same properties as those of the enzyme from the neuroblastoma cell membrane. Thus, the trypsin-like enzyme present in the synaptic membrane would participate in the degradation of dynorphin.
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PMID:Membrane-bound trypsin-like enzyme functioning in degradation of dynorphin in neuroblastoma cells. Purification and characterization. 289 72

The binding of [3H] [D-Ala2, MePhe4, Gly-ol5]enkephalin ([3H]DAGO), [3H]D-Ala2,D-Leu5]enkephalin ([3H]DADLE) and (+/-)-[3H]ethylketocyclazocine ([3H]EKC) to neurotumor tissues derived from S20Y neuroblastoma cells transplanted into A/Jax mice was examined. Specific and saturable binding to [3H]DADLE and [3H]EKC was detected, and the data fit a single homogeneous binding site for each ligand. Scatchard analysis for [3H]DADLE and [3H]EKC yielded Kd values of 0.65 and 0.45 nM, respectively, and Bmax values of 9.2 and 116 fmol/mg protein. Binding was dependent on time, temperature, and pH, and was sensitive to Na+ and guanine nucleotides. Pretreatment of the tumor homogenates with trypsin markedly reduced binding to both ligands, suggesting that the binding sites were proteinaceous in character. Displacement experiments indicated that delta (delta) receptor related compounds (e.g. DPDPE, ICI 174,864) avidly displaced [3H]DADLE, whereas kappa (kappa) related compounds (e.g. U50,488, dynorphin) markedly competed with [3H]EKC. Mu (mu) receptor drugs (e.g. DAGO, beta-FNA, morphine) were not potent in displacing either [3H]DADLE or [3H]EKC. These results are the first to characterize opioid binding sites in tumor tissue. The function of these sites is unclear, but previous evidence as to the growth regulatory properties of endogenous opioid systems may suggest that either one, or both, binding sites may be involved in carcinogenic events.
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PMID:Characterization of opioid binding sites in murine neuroblastoma. 289 49

A dynorphin A 1-13 amide (DYN) derivative biotinylated in position lysine 13 (B-DYN) has been prepared by automated solid-phase peptide synthesis. The derivative retained its ability to bind to avidin, and B-DYN-avidin complex showed a dissociated half-life of 10 hr at 37 degrees C. Opioid receptor binding was measured in membrane preparations of rat brain (mu), NG-108-15 neuroblastoma-glioma hybrid cells (delta), and guinea pig cerebellum (kappa). Biotinyl substitution of DYN either did not effect receptor binding (delta) or slightly reduced binding affinity (mu and kappa). Binding of B-DYN to the kappa receptor was very tight, with an IC50 value in the low picomolar range, while binding to mu and delta sites was over two orders of magnitude lower. Preassociation of B-DYN with avidin resulted in a reduction of the affinities to the investigated opioid receptors by 100- to 1000-fold. However, the apparent affinity of B-DYN-avidin for the kappa-opioid receptor is sufficient to suggest that B-DYN may be a useful tool for kappa-opioid receptor assay, localization, and purification.
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PMID:[Biocytin13]dynorphin A 1-13 amide: a potential probe for the kappa-opioid receptor. 290 85

A membrane-bound enkephalin (ENK) -hydrolyzing amino-peptidase (AP) was partially purified from neuroblastoma (clone N1E-115) cell membranes; enzyme activity was assayed by determination of the leu-enkephalin (LENK) degradation product, tyrosine (Tyr), with HPLC. The enzyme was extracted with Triton X-100, resolved by anion-exchange chromatography and further purified by gel filtration. The overall purification was about 100-fold with a yield of 43%. The apparent Mr value of the AP by gel filtration in the presence of 0.3% Triton X-100 was approx. 400 kDa. In the absence of detergent the apparent Mr value was about 305 kDa. In the elution buffers, where Triton X-100 was omitted, the peptidase activity was lost. The enzyme had a Km of 0.13 mM and a Vmax of 450 nmoles per mg protein per min at 25 degrees C for LENK and exhibited little sensitivity to bestatin (IC50: 200 microM) and puromycin (IC50: 500 microM), but it was strongly inhibited by amastatin (IC50: 8 microM). The enzyme is an amphiphilic membrane protein; the native primary structure is preserved only in the 'detergent form'. It seems to be AP N (EC 3.4.11.2) with an optimum of pH 7.2 to 7.4. We assume that this AP plays the important role in inactivating ENKs on the neuronal level. The ENK-degrading AP, partially purified from primary rat brain astrocyte cell membranes, exhibited a smaller apparent Mr value (130 kDa) and a higher sensitivity to amastatin (IC50: 0.4 microM), bestatin (IC50: 90 nM) and puromycin (IC50: 5 microM) than did the N1E-115 enzyme.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Characterization of the enkephalin-degrading aminopeptidase of neuroblastoma (N1E-115) cell membranes. 312 43

A bioluminescent technique was used to show that murine neuroblastoma (NB) cells or cell-free extracts (H variant) were able to enhance the release of reactive oxygen intermediates (ROI) from peritoneal macrophages in vitro. L-variant NB cells were ineffective. Physiological concentrations of met-enkephalin produced the same effect in vitro but not leu-enkephalin. When both H- and L-variant cells, or their extracts, were incubated together with macrophages, ROI production was not increased. Similar findings were detectable when met- and leu-enkephalin were cultured together with macrophages. In vivo, preliminary studies gave the same results. The concentration rate of met- to leu-enkephalin was higher in H-variant than in L-variant NB cells. We conclude from our results that met-enkephalin can enhance the release of ROI from peritoneal macrophages. The difference in the effects produced by the H and L variants is due to differences in the concentrations of enkephalins released.
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PMID:Enhanced oxygen metabolism of peritoneal macrophages in the presence of murine neuroblastoma cells is partly caused by enkephalins. 317 Jul 21

Five opioid peptides (immunoreactivity) derived from their respective opioid precursors were measured in neuroblastoma-glioma hybrid cells (NG 108CC15; pmol/g protein): heptapeptide (Tyr-Gly-Gly-Phe-Met-Arg-Phe), 13.0 +/- 2.6; alpha-neoendorphin, 6.6 +/- 0.8; dynorphin A, 4.4 +/- 1.5; dynorphin A 1-8, 1.3 +/- 0.29; beta-endorphin, 0.3 +/- 0.13. These peptides originate from preproenkephalin A (heptapeptide), prodynorphin (alpha-neonedorphin, dynorphin A, dynorphin A 1-8) and proopiomelanocortin (beta-endorphin). The data suggest the expression of all three known opioid precursors in a single hybrid cell line, permitting a simultaneous investigation of the processing of different opioid peptides under identical experimental conditions.
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PMID:Evidence for the expression of peptides derived from three opioid precursors in NG 108CC15 hybrid cells. 356 21


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