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)

NELL1 and NELL2 encode cysteine-rich amino acid sequences including six epidermal growth factor-like motifs, which contain signal peptides at the N-terminals. The deduced amino acid sequences of both genes are 55% identical and their cysteine stretch structures are conserved. NELL1 is expressed in the brain and kidney, whereas NELL2 is expressed specifically in the brain. The cell lineage expressing NELLs in the nervous system was investigated in established cell lines and central nervous system tumor tissues obtained from patients by Northern blot and reverse transcriptase-polymerase chain reaction analyses. NELL1 and NELL2 were predominantly expressed in neuroblastoma cell lines and little expressed in glioblastoma cell lines. NELL1 and NELL2 were also expressed in central neurocytoma, medulloblastoma, and some astrocytic tumors. Immunohistochemical analysis revealed that NELL2 protein was localized in the cytoplasm of neurons. These results suggest that NELL2 is predominantly expressed in the neuronal cell lineage in the human nervous system. NELL1 is expressed mainly in tumors in the neuronal cell lineage.
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PMID:Brain specific human genes, NELL1 and NELL2, are predominantly expressed in neuroblastoma and other embryonal neuroepithelial tumors. 1180 83

Prenylcysteine carboxymethyltransferase (pcCMT) is an enzyme that catalyzes the post-translational carboxymethylation of isoprenylated proteins ensuring a more efficient membrane attachment and proper guiding to a specific target membrane. In this paper, we report on modulation of pcCMT activity in retinoic acid (RA)-treated SH-SY5Y neuroblastoma cells using N-acetyl-S-farnesyl-L-cysteine (AFC) as artificial methyl acceptor. In addition, the methylation of endogenous proteins was followed by the vapor phase equilibrium assay and the storage phosphor screen (P-screen) technique with S-adenosyl-[3H-methyl] methionine (AdoMet) as methyl donor. Methylation of AFC was reduced to 75% of that of the control, the most prominent decrease being observed with the post-nuclear membrane fraction as enzyme source. With regard to protein methylation both screening methods yielded analogous results showing the [3H]-labeling of endogenous proteins in the 21-25kDa molecular mass (MM) range to be diminished by nearly 50%. This questions the role of protein carboxymethylation as an essential component of the differentiation process in SH-SY5Y neuroblastoma cells. The P-screen technique revealed that the methylation of other molecular mass proteins was also affected. Both S-adenosylhomocysteine (AdoHcy) and AFC (AdoHcy being the most effective) inhibited endogenous methylation. An interesting feature was that AFC inhibited the protein methylation proportionally more effective in RA-treated cells. Finally, the levels of three small guanosine-5'-triphosphate (GTP) binding proteins were screened upon differentiation showing rab3A to be increased while rhoA and H-ras were decreased.
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PMID:Prenylcysteine carboxymethyltransferase type III activity is decreased in retinoic acid-treated SH-SY5Y neuroblastoma cells. 1190 19

Intracellular reactive iron is a source of free radicals and a possible cause of cell damage. In this study, we analyzed the changes in iron homeostasis generated by iron accumulation in neuroblastoma (N2A) cells and hippocampal neurons. Increasing concentrations of iron in the culture medium elicited increasing amounts of intracellular iron and of the reactive iron pool. The cells had both IRP1 and IRP2 activities, being IRP1 activity quantitatively predominant. When iron in the culture medium increased from 1 to 40 microm, IRP2 activity decreased to nil. In contrast, IRP1 activity decreased when iron increased up to 20 microm, and then, unexpectedly, increased. IRP1 activity at iron concentrations above 20 microm was functional as it correlated with increased (55) Fe uptake. The increase in IRP1 activity was mediated by oxidative-stress as it was largely abolished by N-acetyl-L-cysteine. Culturing cells with iron resulted in proteins and DNA modifications. In summary, iron uptake by N2A cells and hippocampus neurons did not shut off at high iron concentrations in the culture media. As a consequence, iron accumulated and generated oxidative damage. This behavior is probably a consequence of the paradoxical activation of IRP1 at high iron concentrations, a condition that may underlie some processes associated with neuronal degeneration and death.
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PMID:An oxidative stress-mediated positive-feedback iron uptake loop in neuronal cells. 1212 25

SNAP-25 is an integral protein of the plasma membrane involved in neurotransmission and hormone secretion. The cysteine-rich domain of SNAP-25 is essential for membrane binding and plasma-membrane targeting. However, this domain is not required for SNARE complex formation and fusion of membranes in vitro. In this paper, we describe an 'intact-cell'-based system designed to compare the effect of similar amounts of membrane-bound and soluble SNAP-25 proteins on regulated exocytosis. In transfected neuroblastoma cells, Botulinum neurotoxin E (BoNT/E), a protease that cleaves SNAP-25, blocks regulated release of hormone. However, hormone release is rescued by expressing a wild-type SNAP-25 protein resistant to the toxin. BoNT/E-resistant SNAP-25 proteins lacking the cysteine-rich domain or with all the cysteines substituted by alanines do not form SNARE complexes or rescue regulated exocytosis when expressed at the same level as membrane-bound SNAP-25, which is approximately four-fold higher than the endogenous protein. We conclude that the cysteine-rich domain of SNAP-25 is essential for Ca(2+)-dependent hormone release because, by targeting SNAP-25 to the plasma membrane, it increases its local concentration, leading to the formation of enough SNARE complexes to support exocytosis.
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PMID:Plasma membrane targeting of SNAP-25 increases its local concentration and is necessary for SNARE complex formation and regulated exocytosis. 1214 Feb 65

The androgen receptor (AR) N-terminal domain plays a critical role in androgen-responsive gene regulation. A novel AR N-terminal-interacting protein (ARNIP) was isolated using the yeast two-hybrid system and its interaction with amino acids 11-172 of the normal or corresponding region of the polyglutamine-expanded human AR confirmed by glutathione S-transferase pulldown assays. ARNIP cDNAs cloned from NSC-34 (mouse neuroblastoma/spinal cord) or PC-3 (human prostate adenocarcinoma) mRNA encoded highly homologous 30 kDa (261 amino acids) cysteine-rich proteins with a RING-H2 (C3H2C3 zinc finger) domain; this motif is highly conserved in predicted ARNIP-homologous proteins from several other species. Expression of the approximately 1.7 kb ARNIP mRNA was detected in various tissues by Northern blotting, but was highest in mouse testes, kidney and several neuronal cell lines. In addition, the human ARNIP protein was found to be encoded by nine exons spanning 32 kb on chromosome 4q21. In COS-1 cells, coexpression of ARNIP and AR did not affect AR ligand-binding kinetics, nor did ARNIP act as a coactivator or corepressor in transactivation assays. However, AR N-terminal:C-terminal interaction was reduced in the presence of ARNIP. Intriguingly, ARNIP, and in particular its RING-H2 domain, functioned as a ubiquitin-protein ligase in vitro in the presence of a specific ubiquitin-conjugating enzyme, Ubc4-1. Mutation of a single cysteine residue in the ARNIP RING-H2 domain (Cys145Ala) abolished this E3 ubiquitin ligase activity. Fluorescent protein tagging studies revealed that AR-ARNIP interaction was hormone-independent in COS-1 cells, and suggest that colocalization of both AR and ARNIP to the nucleus upon androgen addition may allow ARNIP to play a role in nuclear processes. Thus, identification of a novel AR-interacting protein with ubiquitin ligase activity will stimulate further investigation into the role of ubiquitination and the ubiquitin-proteasome system in AR-mediated cellular functions.
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PMID:Cloning and characterization of an androgen receptor N-terminal-interacting protein with ubiquitin-protein ligase activity. 1220 Feb 28

Exposure of neurons to amyloid-beta (Abeta) is accompanied by a cascade of oxidative damage that initiates with lipid peroxidation followed by subsequent generation of cytosolic free radicals and reactive oxygen species (ROS). The antioxidant vitamin E has been utilized to counteract Abeta-induced oxidative stress. We considered herein whether or not the lipid-solubility of vitamin E limits its neuroprotection to membrane-related oxidative damage, and renders it relatively ineffective where prior lipid peroxidation has already generated cytosolic free radicals and ROS. To test this possibility, we treated differentiated SH-SY-5Y human neuroblastoma with vitamin E or a cell-permeant antioxidant, N-acetyl cysteine (NAC), simultaneously with or 15 min after the application of Abeta. Both vitamin E and NAC prevented Abeta-induced ROS generation when applied simultaneously with Abeta, but only NAC prevented Abeta-induced ROS generation when added to cultures that had previously been exposed to Abeta. These results support the hypothesis that vitamin E can quench Abeta-induced lipid peroxidation, but cannot effectively quench ROS generated by prior lipid peroxidation. These findings in cell culture may provide limited insight into why vitamin E is not fully effective against neurodegeneration in AD in clinical settings, since some neuronal populations are likely to already have been compromised by prior Abeta exposure before vitamin E treatment was initiated.
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PMID:Differential efficacy of lipophilic and cytosolic antioxidants on generation of reactive oxygen species by amyloid-beta. 1221 18

Lectin from a leaf of Erythrina indica was isolated by affinity chromatography on Lactamyl-Seralose 4B. Lectin gave a single band in polyacrylamide gel electrophoresis (PAGE). In SDS-gel electrophoresis under reducing and non-reducing conditions Erythrina indica leaf lectin (EiLL) split into two bands with subunit molecular weights of 30 and 33 kDa, whereas 58 kDa was obtained for the intact lectin by gel filtration on Sephadex G-100. EiLL agglutinated all human RBC types, with a slight preference for the O blood group. Lectin was found to be a glycoprotein with a neutral sugar content of 9.5%. The carbohydrate specificity of lectin was directed towards D-galactose and its derivatives with pronounced preference for lactose. EiLL had pH optima at pH 7.0; above and below this pH lectin lost sugar-binding capability rapidly. Lectin showed broad temperature optima from 25 to 50 degrees C; however, at 55 degrees C EiLL lost more than 90% of its activity and at 60 degrees C it was totally inactivated. The pI of EiLL was found to be 7.6. The amino acid analysis of EiLL indicated that the lectin was rich in acidic as well as hydrophobic amino acids and totally lacked cysteine and methionine. The N-terminal amino acids were Val-Glu-Thr-IIe-Ser-Phe-Ser-Phe-Ser-Glu-Phe-Glu-Ala-Gly-Asn-Asp-X-Leu-Thr-Gln-Glu-Gly-Ala-Ala-Leu-. Chemical modification studies of both EiLL and Erythrina indica seed lectin (EiSL) with phenylglyoxal, DEP and DTNB revealed an absence of arginine, histidine and cysteine, respectively, in or near the ligand-binding site of both lectins. Modification of tyrosine with NAI led to partial inactivation of EiLL and EiSL; however, total inactivation was observed upon NBS-modification of two tryptophan residues in EiSL. Despite the apparent importance of these tryptophan residues for lectin activity they did not seem to have a direct role in binding haptenic sugar as D-galactose did not protect lectin from inactivation by NBS.
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PMID:Purification, some properties of a D-galactose-binding leaf lectin from Erythrina indica and further characterization of seed lectin. 1250 84

A lectin was isolated from the saline extract of Erythrina speciosa seeds by affinity chromatography on lactose-Sepharose. The lectin content was about 265 mg/100g dry flour. E. speciosa seed lectin (EspecL) agglutinated all human RBC types, showing no human blood group specificity; however a slight preference toward the O blood group was evident. The lectin also agglutinated rabbit, sheep, and mouse blood cells and showed no effect on horse erythrocytes. Lactose was the most potent inhibitor of EspecL hemagglutinating activity (minimal inhibitory concentration (MIC)=0.25 mM) followed by N-acetyllactosamine, MIC=0.5mM, and then p-nitrophenyl alpha-galactopyranoside, MIC=2 mM. The lectin was a glycoprotein with a neutral carbohydrate content of 5.5% and had two pI values of 5.8 and 6.1 and E(1%)(1 cm) of 14.5. The native molecular mass of the lectin detected by hydrodynamic light scattering was 58 kDa and when examined by mass spectroscopy and SDS-PAGE it was found to be composed of two identical subunits of molecular mass of 27.6 kDa. The amino acid composition of the lectin revealed that it was rich in acidic and hydroxyl amino acids, contained a lesser amount of methionine, and totally lacked cysteine. The N-terminal of the lectin shared major similarities with other reported Erythrina lectins. The lectin was a metaloprotein that needed both Ca(2+) and Mn(2+) ions for its activity. Removal of these metals by EDTA rendered the lectin inactive whereas their addition restored the activity. EspecL was acidic pH sensitive and totally lost its activity when incubated with all pH values between pH 3 and pH 6. Above pH 6 and to pH 9.6 there was no effect on the lectin activity. At 65 degrees C for more than 90 min the lectin was fairly stable; however, when heated at 70 degrees C for 10 min it lost more than 80% of its original activity and was totally inactivated at 80 degrees C for less than 10 min. Fluorescence studies of EspecL indicated that tryptophan residues were present in a highly hydrophobic environment, and binding of lactose to EspecL neither quenched tryptophan fluorescence nor altered lambda(max) position. Treating purified EspecL with NBS an affinity-modifying reagent specific for tryptophan totally inactivated the lectin with total modification of three tryptophan residues. Of these residues only the third modified residue seemed to play a crucial role in the lectin activity. Addition of lactose to the assay medium did not provide protection against NBS modification which indicated that tryptophan might not be directly involved in the binding of haptenic sugar D-galactose. Modification of tyrosine with N-acetylimidazole led to a 50% drop in EspecL activity with concomitant acetylation of six tyrosine residues. The secondary structure of EspecL as studied by circular dichroism was found to be a typical beta-pleated-sheet structure which is comparable to the CD structure of Erythrina corallodendron lectin. Binding of lactose did not alter the EspecL secondary structure as revealed by CD examination.
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PMID:Isolation, purification, and physicochemical characterization of a D-galactose-binding lectin from seeds of Erythrina speciosa. 1257 81

Synthesis and structure-activity relationship (SAR) study of L-amino acid-based N-type calcium channel blockers are described. The compounds synthesized were evaluated for inhibitory activity against both N-type and L-type calcium channels focusing on selectivity to reduce cardiovascular side effects due to blocking of L-type calcium channels. In the course of screening of our compound library, N-(t-butoxycarbonyl)-L-aspartic acid derivative 1a was identified as an initial lead compound for a new series of N-type calcium channel blockers, which inhibited calcium influx into IMR-32 human neuroblastoma cells with an IC(50) of 3.4 microM. Compound 1a also exhibited blockade of N-type calcium channel current in electrophysiological experiment using IMR-32 cells (34% inhibition at 10 microM, n=3). As a consequence of conversion of amino acid residue of 1a, compound 12a, that include N-(t-butoxycarbonyl)-L-cysteine, was found to be a potent N-type calcium channel blocker with an IC(50) of 0.61 microM. Thus, L-cysteine was selected as a potential structural motif for further modification. Optimization of C- and N-terminals of L-cysteine using S-cyclohexylmethyl-L-cysteine as a central scaffold led to potent and selective N-type calcium channel blocker 21f, which showed improved inhibitory potency (IC(50) 0.12 microM) and 12-fold selectivity for N-type calcium channels over L-type channels.
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PMID:Structure-activity study of L-amino acid-based N-type calcium channel blockers. 1265 76

The exact pathogenesis of neuronal death following bleeding in brain parenchyma is still unknown. Hemoglobin (Hb) toxicity has been postulated to be one of the underlying mechanisms. The purpose of this study was to examine the possible contribution to neurotoxicity of each of the Hb compounds and to characterize the death pathway. Pheochromocytoma (PC12) and neuroblastoma (SH- SY5Y) cell lines were exposed to Hb, globin, hemin, protoporphyrin IX and iron for 1.5- 24 h. We found that Hb and hemin are highly toxic (LD(50) of 8 and 20 &mgr; mol/l, respectively) as compared to globin that was not toxic. In addition, protoporphyrin IX and iron, compounds of hemin, were less toxic than hemin itself (LD(50) of 962 and 2070 &mgr; mol/l respectively). We also demonstrated that non-specific protein digestion with proteinase-K, markedly increased Hb toxicity. Hemin-treated cells caused a typical apoptotic cell death pattern as indicated by DNA fragmentation, caspase activation and reduction in the mitochondrial membrane potential. Treatment with the antioxidant N-acetyl-L-cysteine or iron chelator, deferoxamine, diminished hemin-induced cell death, indicating a role of oxidative stress in this deleterious process. Thus, therapeutic strategies, based on antioxidant, iron chelator and anti-apoptotic agents may be effective in counteracting Hb neurotoxicity.
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PMID:Hemin-induced apoptosis in PC12 and neuroblastoma cells: implications for local neuronal death associated with intracerebral hemorrhage. 1270 99


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