Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Angiotensin II (Ang-II) receptors were solubilized from differentiated N1E-115 neuroblastoma cell membranes with the zwitterionic detergent 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS), whereas other detergents, such as digitonin, sodium cholate, and Triton X-100, were much less effective. Binding of 125I-Ang-II or the antagonist 125I-Sar1,Ile8-Ang-II to 1% CHAPS-solubilized membranes was saturable and of high affinity. Moreover, these solubilized receptors retained the pharmacological specificity characteristic of particulate receptors. Covalent cross-linking of 125I-Ang-II to either particulate or solubilized membrane fractions, with the homobifunctional cross-linker disuccinimidyl suberate, followed by size exclusion chromatography or sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis, resulted in the identification of the same two distinct 125I-Ang-II binding entities, with approximate molecular masses of 111 kDa and 68 kDa. The estimated molecular weights of the Ang-II binding sites in differentiated N1E-115 cells are in good agreement with the molecular weights obtained previously from solubilized rat brain membranes, suggesting that the N1E-115 Ang-II receptors are similar to those present in the brain. Finally, solubilized N1E-115 membranes could be purified by Ang-II affinity chromatography, resulting in only a single protein (66 kDa), which retained its ability to specifically bind 125I-Ang-II.
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PMID:Biochemical analysis of solubilized angiotensin II receptors from murine neuroblastoma N1E-115 cells by covalent cross-linking and affinity purification. 194 41

Recent studies have suggested important roles for certain proteases and protease inhibitors in the growth and development of the CNS. In the present studies, inhibitors of urokinase or thrombin in cultured neural cells and serum-free medium from the cells were identified by screening for components that formed sodium dodecyl sulfate-stable complexes with 125I-urokinase or 125I-thrombin. Rinsed glioblastoma possessed two components that complexed 125I-urokinase. One was type 1 plasminogen activator inhibitor (PAI-1), because the 125I-urokinase-containing complexes were immunoprecipitated with anti-PAI-1 antibodies. The other component formed complexes with 125I-urokinase that were not recognized by antibodies to PAI-1 or protease nexin-1 (PN-1). Its identity is unknown. In addition to these cell-bound components, the glioblastoma cells also secreted two inhibitors that formed complexes with 125I-urokinase; one was PAI-1, and the other was PN-1. The secreted PN-1 also formed complexes with 125I-thrombin. It was the only thrombin inhibitor detected in these studies. Human neuroblastoma cells did not contain components that formed detectable complexes with either 125I-urokinase or 125I-thrombin. However, human neuroblastoma cells did contain very low levels of PN-1 mRNA and PN-1 protein. Added PN-1 bound to the surface of both glioblastoma and neuroblastoma cells. This interaction accelerated the inhibition of thrombin by PN-1 and blocked the ability of PN-1 to form complexes with 125I-urokinase. Thus, cell-bound PN-1 was a specific thrombin inhibitor.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Inhibitors of urokinase and thrombin in cultured neural cells. 198 20

From the human teratocarcinoma-derived cell line PA-1, we established a clonal line, PA-1/NR, that stably produced a distinct cellular arrangement of neural rosettes when cultured as in vitro multicellular spheroids for 3 weeks. On immunofluorescence staining and fluorescence-activated cell sorter analyses, PA-1/NR cells in monolayer expressed the neuroectoderm-associated antigens HNK-1, NC-1, and A2B5 and the neuroblastoma-associated antigens KP-NAC8 and KP-NAC10 but lacked human embryonal carcinoma antigens, SSEA-3 or K21 antigen. Here, we investigated the developmental process of rosette formation with respect to morphological features, distribution of mitotic cells, and expression of multiple lineage-related markers and extracellular matrix (ECM) components. Ultrastructural examination of these rosettes disclosed a well-defined cavity radially surrounded by wedge-shaped or pseudostratified cells, apical microvilli and junctional complexes, and basal laminae and collagen fibrils at their basal surface. In these rosettes, many proliferating cells were detected by the immunohistochemical staining of cells incorporating bromodeoxyuridine. PA-1/NR spheroids consistently displayed neuron-specific enolase, S-100 protein, and vimentin but not glial fibrillary acidic protein, neurofilament proteins, or myelin basic protein. The rosette formation accompanied a strikingly polarized and overlapped deposition of ECM components including tenascin-carrying HNK-1 epitopes, laminin, type IV collagen, heparan, and chondroitin sulfate proteoglycans. Immunoblotting analyses showed that laminin B1 and B2 chains were constitutively expressed, whereas a fully assembled form of laminin and type IV collagen appeared only after spheroid development, suggesting that these ECM components play a morphogenetically important role in rosette formation. Close similarities between these rosettes and the neural tube of humans and experimental animals in the morphogenetic process and ECM formation lead us to propose that the PA-1/NR spheroids provide an in vitro model for the study of the earliest stage of human neurogenesis.
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PMID:Neural rosette formation within in vitro spheroids of a clonal human teratocarcinoma cell line, PA-1/NR: role of extracellular matrix components in the morphogenesis. 202 44

In this study, hepatic microsomes from 5,6-benzoflavone induced C57BL/10 mice were used. To inhibit monooxygenase activities, the monoclonal antibody MAb 1-7-1 recognizing two isoenzymes of methylcholanthrene-induced cytochrome P-450 was applied. Microsomes were incubated with tritium labeled benzo(a)pyrene [G-3H]BP for 10 min at 37 degrees C. The incubation mixture contained: 50 mM potassium phosphate buffer, pH 7.25; 30 mM KCl; 3 mM MgCl2; 2 mM NADPH; 80 microM [G-3H]BP (specific activity 50 mCi/mmol); and monoclonal antibody MAb 1-7-1 or ascites fluid (NBS) containing nonspecific IgG as a control. The ratio of antibody protein/microsomal protein was 2:5. BP metabolites were extracted from incubation mixtures by ethyl acetate. The organic layer was dried over sodium sulfate, and evaporated under a stream of nitrogen. To separate BP metabolites HPLC technology was used. The column was eluted with methanol gradient (60-100%) for 45 minutes. The radio-activity of collected samples was determined using liquid scintillation counter. Differential inhibitory effects of MAb 1-7-1 on BP-metabolites formation were found, e.g. 7,8-diol was inhibited by 86.1% and quinones by 62.5%. The predominant metabolite, 3-OH-BP, was inhibited by 80.4%. Moreover, it was found that MAb 1-7-1 inhibition of benzo(a)pyrene hydroxylase activity (by 75.8%, as measured by fluorescent technique) was very similar to the inhibition of 3-OH-BP along with 9-OH-BP formation (as measured by HPLC).
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PMID:[Effect of monoclonal antibody against methylcholanthrene-induced cytochrome P-450 forms on benzo(a)pyrene metabolism in hepatic microsomes of C57BL/10 mice]. 209 79

The regulation of GTP-binding proteins (G proteins) was examined during the course of differentiation of neuroblastoma N1E-115 cells. N1E-115 cell membranes possess three Bordetella pertussis toxin (PTX) substrates assigned to alpha-subunits (G alpha) of Go (a G protein of unknown function) and "Gi (a G protein inhibitory to adenylate cyclase)-like" proteins and one substrate of Vibrio cholerae toxin corresponding to an alpha-subunit of Gs (a G protein stimulatory to adenylate cyclase). In undifferentiated cells, only one form of Go alpha was found, having a pI of 5.8 Go alpha content increased by approximately twofold from the undifferentiated state to 96 h of cell differentiation. This is mainly due to the appearance of another Go alpha form having a pI of 5.55. Both Go alpha isoforms have similar sizes on sodium dodecyl sulfate-polyacrylamide gels, are recognized by polyclonal antibodies to bovine brain Go alpha, are ADP-ribosylated by PTX, and are covalently myristylated in whole N1E-115 cells. In addition, immunofluorescent staining of N1E-115 cells with Go alpha antibodies revealed that association of Go alpha with the plasma membrane appears to coincide with the expression of the most acidic isoform and morphological cell differentiation. In contrast, the levels of both Gi alpha and Gs alpha did not significantly change, whereas that of the common beta-subunit increased by approximately 30% over the same period. These results demonstrate specific regulation of the expression of Go alpha during neuronal differentiation.
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PMID:Neuroblastoma differentiation involves the expression of two isoforms of the alpha-subunit of Go. 210 77

The complete amino acid sequence of human retina and muscle aldose reductase was determined by nucleotide analysis of cDNA clones isolated using synthetic oligonucleotide probes based on partial amino acid sequences of purified human psoas muscle aldose reductase. The cDNA sequence differs substantially in the noncoding and coding regions of recently published sequences of this enzyme. The mRNA for aldose reductase was abundantly expressed in HeLa cells, but only scarcely in a neuroblastoma cell line. Recombinant baculovirus containing one of the muscle cDNA clones was constructed and used to infect Spodoptera frugiperda (SF9) cells. A prominent protein with an apparent molecular size of 36 kDa was identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the culture medium as well as in the homogenate of SF9 cells after 2 days of infection. Culture medium or the supernatant fraction of cell homogenates containing this protein had high aldose reductase activity which showed characteristics of the reported human enzyme. These findings indicate that the amino acid sequence reported in this paper represents human retina and muscle aldose reductase and that functional human aldose reductase can be expressed in large amounts in a baculovirus expression system. The result should facilitate refined structural analysis and the development of new specific aldose reductase inhibitors for the treatment of diabetic complications.
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PMID:Cloning and expression of human aldose reductase. 211 46

Pharmacological studies indicate that peptide YY (PYY) and neuropeptide Y interact with multiple binding sites, categorized as Y1 and Y2 subtypes. In order to identify and structurally characterize the Y1 and Y2 receptors we covalently cross-linked [125I-Tyr36]PYY to its receptors. The Y2 receptor in rat hippocampus and rabbit kidney membranes was affinity labeled using different homo- and heterobifunctional cross-linking reagents. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography resulted in a major labeled protein band of Mr = 50,000 in both hippocampal and kidney membranes, which was unaffected by reducing agents. The Y1 receptor was analyzed in membranes from the MC-IXC human neuroblastoma cell line. Autoradiography revealed two labeled bands at Mr = 70,000 and 45,000. As the intensity of the Mr = 45,000 band was reduced by protease inhibitors, it is likely that this band is a degradation product of the larger band. Labeling of these proteins was obtained only when N-5-azido-2-nitrobenzoyloxysuccinimide was employed for cross-linking followed by exposure to UV light. Labeling of the two cross-linked bands was unaffected by reducing agents. The binding of radiolabeled PYY and the intensity of the cross-linked bands, for both the Y1 and Y2 receptors, were inhibited similarly in a dose-dependent manner by increasing concentrations of unlabeled PYY. When exposed to agarose-coupled lectins, the detergent-solubilized Y1 receptor-hormone complex was completely adsorbed by wheat germ agglutinin and partially by ricin communis II. The cross-linked Y2 receptor was almost totally adsorbed by wheat germ agglutinin-agarose and partially adsorbed by concanavalin A. The adsorptions were in all cases blocked by the appropriate hapten sugar. These results indicate that the Y1 receptor is a glycoprotein with a Mr = 70,000 binding subunit, whereas the Y2 receptor is a glycoprotein with a Mr = 50,000 binding subunit. These results provide evidence that the Y1 and Y2 subtypes of neuropeptide Y and PYY receptors, previously characterized pharmacologically, are structurally distinct glycoproteins, not disulfide-linked to other subunits.
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PMID:Structural characterization of Y1 and Y2 receptors for neuropeptide Y and peptide YY by affinity cross-linking. 215 75

Screening serum by enzyme-linked immunosorbent assay (ELISA) to paraformaldehyde-fixed neuroblastoma cells revealed spontaneous neuron-reactive antibodies in three strains of autoimmune mice not present in comparable studies of BALB/c mice. Immunoglobulin isolation from pooled sera by either ammonium sulfate precipitation or passage over a protein G column enabled quantitative binding by (1) ELISA to neuroblastoma cells and (2) Western blots of plasma membrane preparations of brain cortex and neuroblastoma cells. The antibodies recognized proteins of apparent molecular weights 101,000, 68,000, 63,000, 57,000, 53,000, 43,000, 39,000, and 31,000 Da on the brain cortex and 63,000, 57,000, and 43,000 Da on the neuroblastoma cell membranes. The class of antibody binding was predominantly IgG in the MRL/lpr and IgM in the NZB/W. Differences between MRL/lpr, NZB/W and BXSB mice were observed although it is not yet apparent if this represents a difference in autoantibody production between the strains.
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PMID:Immunoglobulin binding to neuronal cell surface epitopes in murine systemic lupus erythematosus. 222 4

Initial studies described the significance of heparan sulfate proteoglycans of Balb/c 3T3 cells in their adhesion on fibronectin matrices, including their binding to multiple domains in FN, the importance of this binding in microfilament and close contact formation, and the cooperativity of both HS-PG and 140k glycoprotein integrin's binding to FN to achieve tight-focal contacts under cells. These analyses utilized model HS-binding proteins, such as platelet factor 4, and proteolytic fragments of FN with differing binding activities in both cell biological analyses of adhesion responses and in biochemical analyses of the HS-PG in the adhesion sites. In contrast, dermatan sulfate proteoglycans (DS-PG) inhibit 3T3 adhesion on FN but not on collagen; of special note is the discovery that certain integrin-binding fragments of FN also contain a third HS/DS-binding domain that is cryptic and that provides a more effective mechanism for inhibiting integrin: FN binding. Kirsten Ras oncogene-transformed 3T3 cells and their nude-mouse-derived primary or lung metastatic tumors are also being analyzed by similar approaches. HS-PGs in the adhesion sites of these tumor populations undergo extensive catabolism, resulting in alteration of their binding to FN affinity columns (and by implication alteration in adhesion responses of these tumor cells on FN matrices). Functions for HS-PG on the surface of neuronal cell derivatives, e.g., neuroblastoma cells derived from the neural crest of the embryo and potentially related in some ways to peripheral neurons, are also being explored. HS-binding fragments of FN or PF4 facilitate attachment and spreading of neuroblastoma cells but not neurite outgrowth, contrasting with the ability of dorsal root ganglion neurons to extend neurites on HS-binding substrata. The catabolism of HS-PG in neuroblastoma adhesion sites is minimal, indicating that this cannot be the explanation for incompetence in neurite extension. Neurite extension by neuroblastoma cells on FN results from three different and overlapping binding activities of non-PG receptors on the cell surface--RGDS-dependent binding to integrin, an RGDS-independent mechanism (perhaps a cell type-specific domain), and a ganglioside-dependent process. However, these neurite-extending reactions can be modulated either by exogenous addition of proteoglycans acting in a "trans" manner with the cell surface or by endogenous HG-PG acting in a "cis" manner with one or more of these receptors.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Heparan sulfate proteoglycans of Ras-transformed 3T3 or neuroblastoma cells. Differing functions in adhesion on fibronectin. 252 58

The relationship between plasminogen activator (PA)/plasminogen activator inhibitor (PAI) activity and morphological differentiation was investigated in human neuroblastoma (NB) cells treated with retinoic acid (RA). Conditioned medium from nine NB cell lines and one closely related neuroepithelioma line was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and zymography. All NB cell lines were shown to secrete urokinase (UK)-type PA (mol. wt., 52 kDa), and all except two produced tissue PA (mol. wt., 65 kDa). Identification of the PAs was made based on molecular weight and sensitivity to inhibition by anti-UK and anti-tPA antibodies. Several cell lines expressed PA inhibitory molecules; two molecular-weight forms were observed (35 and 40 kDa) in different cell lines. Complex formation with [125]I-labelled proteases revealed specific binding with UK and trypsin but not thrombin, plasmin, or kallikrein. After treatment for 6 days with 1 microM RA, six of the cell lines exhibited an increase in cell-associated and/or secreted tPA activity, corresponding to morphological differentiation of the cells as manifested by extensive neurite outgrowth. A decrease in UK and UK-complex secretion was observed in several of these cell lines. Three cell lines exhibiting no detectable morphological alterations with RA treatment also showed no dramatic changes in PA/PAI activity. These results suggest that morphological differentiation of NB cells may be associated with alterations in the regulation of PA activity.
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PMID:Effect of retinoic acid on human neuroblastoma: correlation between morphological differentiation and changes in plasminogen activator and inhibitor activity. 259 Sep 98


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