Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0027819 (neuroblastoma)
 27,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The binding sites for the lectins wheat germ agglutinin, Ricinus communis agglutinin and concanavalin A on mouse neuroblastoma cell membranes were identified using SDS-gel electrophoresis in combination with fluorescent lectins. Ricinus communis agglutinin and wheat germ agglutinin were found to bind almost exclusively to a single polypeptide with an apparent molecular weight of 30 000. Concanavalin A labeled over 20 different polypeptides, most with molecular weights greater than 50 000. However, when the neuroblastoma cells were treated with concanavalin A so as to internalize all the concanavalin A binding sites visible at the level of the fluorescent microscope and the purified plasma membranes analyzed for their concanavalin A binding polypeptides, only four of the 20 glycopolypeptides were missing or significantly reduced in amount. Thus, these four high molecular weight concanavalin A-binding polypeptides appear to be the major cell surface receptors for concanavalin A. Binding studies with iodinated concanavalin A indicated that these polypeptides represented the high affinity concanavalin A binding sites (Kd = 2 . 10(-7) M). Low affinity concanavalin A binding sites were present on the cell surface after internalization of high affinity concanavalin A binding sites.
 ...
PMID:Analysis of lectin-specific cell surface glycoprotein on neuroblastoma cells. 689 23

A simple method is described that permitted rapid isolation of plasma membranes from mouse N-18 neuroblastoma cells. The purified plasma membranes gave a 10-fold increase in the specific activity of incorporated [3H]fucose over that of the cell homogenate. The specific activities of two other membrane markers, 5'-nucleotidase and alkaline phosphatase, increased 11-fold and 15-fold, respectively. Metabolic labeling with [3H]fucose identified a major fucosyl glycoprotein with apparent molecular weight of 92 000. Three surface labeling methods together with SDS-polyacrylamide gel electrophoresis and fluorography were used to characterize and compare the surface glycoproteins of undifferentiated and differentiated N-18 cells. The galactose oxidase/NaB3H4 method labeled two major galactoproteins (Mr = 52 000, 42 000) in both undifferentiated and differentiated cells. The neuraminidase/galactose oxidase/NaB3H4 method revealed many sialylgalactoproteins. Among them, the 220-kdalton, 150-kdalton and 130-kdalton bands were at least 100% more prominently labeled in the differentiated cells whereas the 76-kdalton and 72-kdalton bands were less prominently labeled in the differentiated cells when compared to their undifferentiated counterparts. The prominently iodinated protein bands in the undifferentiated cells had apparent molecular weights of 130 000, 92 000, 76 000 and 72 000 as compared to 150-, 130-, 92- and 76-kdalton bands in the differentiated cells. The labeling data obtained will enable us to further study the changes of these identified surface glycoproteins, both quantitatively and topologically, during the differentiation of neuroblastoma cells.
 ...
PMID:Identification of exposed surface glycoproteins in undifferentiated and differentiated mouse N-18 neuroblastoma cells. 705 92

We have previously identified a cell surface glycoprotein of the mouse nervous system named brain cell surface protein-2 (BSP-2). Here we report that this antigen is not a single, discrete entity, but a family of antigenically and structurally related molecules. Three components of 180, 140, and 120 K were characteristic for more mature nervous tissues. Adult cerebral cortex contained the 140-K and 120-K antigens, adult spinal cord only the 120-K, and dorsal root ganglia from young mice mainly the 180-K component. Very different forms of the antigen that migrated as a diffuse zone from 180-250-K in SDS-polyacrylamide gels were found in immature nervous tissues. A molecule different from the previous ones was found in a neuroblastoma line. Evidence is presented that the structural diversity of BSP-2 is due to differences in glycosylation. This result indicates that cell type- and developmental stage-specific glycoprotein patterns previously found in the nervous system may in part be due to different glycosylation of identical polypeptides. The finding that a neural cell surface protein may be glycosylated in different ways has important implications for the generation of cell surface specificity.
 ...
PMID:Tissue- and developmental stage-specific forms of a neural cell surface antigen linked to differences in glycosylation of a common polypeptide. 718 49

Two spontaneously arising variant clones were selected from the N18 neuroblastoma cell line solely on the basis of their flattened morphology and tight adherence to the culture flask. Two other clones having the round loosely adherent morphology typical of the parent line were also selected, and flat variants were shown to arise in them upon prolonged cultivation. The flat variant clones have slower growth rates in culture, lower cloning efficiencies in suspension, and reduced acetylcholinesterase inducibility when compared with either the parent N18 line or the round cell clones. Cells of both morphologic types have high levels of plasminogen activator and are tumorigenic, although the variants have a slower growth rate in vivo, consistent with their slower growth rate in culture. SDS-polyacrylamide gel electrophoresis of total protein from the two cell types shows that the flat variants have increased amounts of a 200,000 molecular weight polypeptide that has tentatively been identified as the heavy chain of myosin. Round morphological revertants from one of the flat variant clones exhibited growth characteristics typical of the parent N18 line, but their content of myosin heavy chain, although reduced, was not so low as that in the round cell clones originally isolated. The possibility of a causal relationship between flat morphology, reduced suspension cloning efficiency, and increased content of myosin heavy chain is discussed.
 ...
PMID:Clonal variation in cultured neuroblastoma cells. I. Isolation and characterization of variants. 719 8

Neuro-2a neuroblastoma cells, when differentiated via a cAMP-dependent pathway by treatment with anti-GM3 monoclonal antibody, accumulated a high level of pp60c-src protein and pp60c-src kinase activity just before the onset of neurite formation. The specific kinase activity of the accumulated c-src protein was found to be comparable to that of normal cerebellar neurons, but was about 6- to 8-fold higher than that of normal astrocytes. These results, and migrations of peptide fragments in the SDS-polyacrylamide gels after V8 proteolysis, strongly indicate the accumulation of the neuron-specific isoform of the c-src protein (pp60c-srcN) in the GM3 antibody-treated Neuro-2a cells. Similar high levels of pp60c-src protein and pp60c-src kinase activity were observed in the Neuro-2a cells differentiated via a cAMP-dependent pathway by treatment with dibutyryl cAMP, but not in the same cell line when differentiated via a cAMP-independent pathway with 5-bromo-2'-deoxyuridine. These results demonstrate that the accumulation of high levels of the neuron-specific isoform of the pp60c-src protein (pp60c-srcN) in the Neuro-2a neuroblastoma cells depends on the specific signal transduction pathway involved during the differentiation of these cells.
 ...
PMID:Accumulation of high level of pp60c-srcN is an early event during GM3-antibody mediated differentiation of neuro-2a neuroblastoma cells. 750 9

Alz-50, a monoclonal antibody originally prepared using Alzheimer brain homogenates, reacts with PHF-tau and normal tau on immunoblots, and stains specific neuronal populations in sections from Alzheimer's disease brain. Although the Alz-50 epitope has been mapped to amino acids 2-10 present in all human tau isoforms, minimal Alz-50 immunoreactivity is present in tissue from control brain, suggesting Alz-50 binding may be dependent on tau conformational differences. The absence of conclusive results concerning Alz-50 binding presents the possibility of Alz-50 immunoreactivity with proteins other than tau. The present study demonstrates Alz-50 cross-reactivity with denatured bovine serum albumin (BSA) and human serum albumin (HSA). Using LA-N-5 neuroblastoma cells, BSA from serum-containing media was present in cell homogenates and was found to be Alz-50-reactive on immunoblots. In fact, Alz-50 (0.1 microgram/ml) recognized as little as 78 ng of BSA and 312 ng of HSA. Since Alz-50 does not recognize native BSA, blocking of immunoblots with 3% BSA did not alter Alz-50 reactivity with tau from LA-N-5 cells. On SDS-polyacrylamide gels, HSA (approximately 69 kDa) migrates very closely to the pattern of A68 (PHF-tau) from Alzheimer brain homogenates. Hence, the presence of BSA or other albumins in cell or brain homogenates may be an important concern when using the Alz-50 antibody.
 ...
PMID:Monoclonal antibody Alz-50 reacts with bovine and human serum albumin. 753 57

Sensitive and specific two-side enzyme immunoassays (two-site EIAs) for pituitary adenylate cyclase activating polypeptides, PACAP38, and PACAP27, have been established using six monoclonal antibodies against PACAP38, and a rabbit antibody against a C-terminal portion of PACAP27. In extracts of rat hypothalamus, these EIAs detected not only PACAP38 and PACAP27 but also an immunoreactive (ir-) PACAP lacking an epitope of a monoclonal antibody, PA-1C, which recognizes the C-terminal portion of PACAP38. By the use of these EIAs, it was found that one of the human neuroblastoma cell lines, IMR-32, produced ir-PACAP. In reverse-phase (RP-)HPLC, intracellular and extracellular ir-PACAPs were separated into two peaks, of which one was eluted at a position close to that of PACAP38 and the other in rather hydrophobic fractions. Those ir-PACAPs also lacked PA-1C epitope of PACAP38. SDS-PAGE and immunoblot analysis of the two peaks of the RP-HPLC indicated that they consisted of several components including those with apparent molecular weights of 6.5 k and 10 k for the first peak ir-PACAP, and 14 k and 20 k for the second peak ir-PACAP. These results indicate that IMR-32 produces a precursor of PACAP and related peptides generated in various processing steps. Although the significance of the modification in the C-terminus of PACAP38 is unknown, IMR-32 may be a cell line useful for studying the regulation of the biosynthesis of PACAP.
 ...
PMID:Production of immunoreactive pituitary adenylate cyclase activating polypeptide (PACAP) by human neuroblastoma cells, IMR-32: detection and characterization with monoclonal and polyclonal antibodies against different epitopes of PACAP. 768 92

The phosphoinositidase C-linked G proteins Gq alpha and G11 alpha are highly similar and comigrate in 10% (w/v) acrylamide SDS-PAGE. Antisera generated against regions common between these G proteins thus detect a composite of the two polypeptides following resolution in such gels. Using SDS-PAGE conditions which allow resolution of Gq alpha and G11 alpha in rodent brain and neuroblastoma cell lines it was observed that primate frontal cortex and neuroblastoma cell lines did not express a polypeptide which comigrated with rodent G11 alpha. Species diversity in G-protein sequences is extremely limited; however, immunoblotting primate cells and frontal cortex with a G11 alpha-specific antiserum demonstrated this to be due to a difference in mobility of rodent and primate G11 alpha under these conditions rather than lack of expression of G11 alpha by primates. A cDNA encoding mouse G11 alpha was transiently expressed in monkey COS-1 cells and membranes from these cells were immunoblotted with antisera able to identify primate and rodent G11 alpha equally, following SDS-PAGE under the resolving conditions. Both mouse and monkey G11 alpha could be detected concurrently and unambiguously following transfection. This is the first demonstration that species variants of the same G protein expressed in a single cell can be detected simultaneously.
 ...
PMID:Concurrent specific immunological detection of both primate and rodent forms of the guanine nucleotide binding protein G11 alpha following their coexpression. 803 5

A biologically active fusion protein comprising a short hydrophilic leader peptide fused to the N-terminus of rat CNTF was generated using commercially available materials. The coding region for rat CNTF was sub-cloned into the pFLAG-1 vector and transfected into the JM 109 strain of E. coli. The transfected cells expressed high levels of the fusion protein (FLAG-CNTF) following induction by isopropyl beta-D-thiogalactoside (IPTG). FLAG-CNTF is expressed as insoluble material that was resolubilized by extraction with guanidine hydrochloride and purified by immuno-affinity chromatography. Analysis of the purified material by reverse phase HPLC and Western blot analysis indicated that FLAG-CNTF was composed of two closely related species that are greater than 99% pure after affinity chromatography. The purified FLAG-CNTF migrated as a 27 KD doublet on SDS polyacrylamide gel electrophoresis. Both bands of the doublet were shown to contain the FLAG peptide and CNTF by Western blot analysis, and amino acid sequence analysis demonstrated a single amino acid sequence corresponding to FLAG peptide and the N-terminus of CNTF. The purified fusion protein was tested for biological activity using the IMR-32 human neuroblastoma cell line. Treatment of IMR-32 cells with FLAG-CNTF increased the level of choline acetyltransferase (ChAT) in these cells 2-3-fold over that of control cells in a dose dependent manner. A direct comparison of the effects of FLAG-CNTF and recombinant human CNTF on IMR-32 ChAT activity showed that both factors exhibited similar potencies.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Preparation and affinity purification of a novel, biologically active, CNTF fusion protein. 807 97

We developed an IgG1 mouse monoclonal antibody (ONS-M21) directed against a cell surface antigen of medulloblastomas and gliomas in immunisation of mice with the ONS-76 medulloblastoma cell line. The antibody specifically reacted with medulloblastomas, supratentorial primitive neuroectodermal tumours (SPNETs) and gliomas, but not with other neuroectodermally derived tumours (neuroblastoma and melanoma) or with other kinds of tumours (meningioma, neurinoma, leukaemia, and small cell lung cancer). No reactivity was identified with normal body tissues, including peripheral blood cells. Characterisation of the ONS-M21 antigen showed that it was a trypsin-sensitive glycoprotein with a molecular weight of 80 kDa on SDS-PAGE. The pattern of reactivity and the biochemical properties of this antigen were different from those of other markers of medulloblastoma. These results indicate that ONS-M21 detects a new tumour-associated cell surface antigen specifically expressed by medulloblastomas, SPNETs, and gliomas. This is the first report that medulloblastomas may share common cell surface antigens with gliomas, although most studies have concluded that medulloblastoma has a predominantly neuronal phenotype. The lack of reactivity with normal tissue implies that ONS-M21 has potential applications as both a diagnostic tool and a therapeutic agent.
 ...
PMID:Characterisation of a new mouse monoclonal antibody (ONS-M21) reactive with both medulloblastomas and gliomas. 821 97


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>