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)

Cyclic AMP can profoundly influence the growth and differentiation of neuronal cells in culture. In this study, the relationship between this second messenger signal transduction pathway, cell differentiation, and the expression of a retinoid-responsive, thymosin beta-10 gene was examined. Thymosin beta-10 and cognate mRNA were expressed at high levels in actively proliferating rat B104 neuroblastoma cells cultured in medium containing 10% FCS. These cells were induced to differentiate in the presence of the cAMP analog N6, 2'-O-dibutyryladenosine 3':5'-cyclic monophosphate (Bt2-cAMP) (1 mM) and the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX) (100 microM). Expression of thymosin beta-10 mRNA was markedly inhibited (greater than 90% and 70%, respectively) by these compounds. Addition of sodium butyrate (NaB, 1 mM) indicated that at least part of the inhibitory actions of Bt2-cAMP were due to esterase-induced release of butyrate from this compound. Adenosine (50 microM), a metabolic precursor to endogenous cyclic AMP, also inhibited accumulation of thymosin beta-10 mRNA (to less than 70% of control levels). The inhibitory action of Bt2-cAMP upon thymosin beta-10 mRNA levels was time dependent; levels were inhibited by greater than 50% 24 hours after addition of the cAMP analog and by greater than 90% after 72 hours. Serum starvation (0.2% FCS for seven days) provoked a marked increase in neurite out-growth; this morphological change was also accompanied by a modest inhibition of thymosin beta-10 mRNA accumulation. These findings together with previous observations imply that both cyclic AMP-dependent and retinoid-responsive mechanisms coordinate thymosin beta-10 gene expression during neuroembryogenesis.
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PMID:Influence of cyclic AMP and serum factors upon expression of a retinoid-responsive gene in neuroblastoma cells. 137 94

Certain organophosphorus (OP) compounds produce a delayed neuropathy in man and susceptible animal species after early inhibition and aging of the enzyme, neurotoxic esterase (NTE). In this study, the human neuroblastoma cell line, SY-5Y, was used to examine the time course of inhibition and aging of NTE after toxicant treatment. The time course and extent of detrimental effects on this enzyme were similar in the SY-5Y cells to those observed in homogenized chicken brain tissue after the same treatments. The results indicate that the SY-5Y model system shows promise for use in the determination of initial mechanisms contributing to the development of organophosphorus-induced delayed neuropathy.
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PMID:Development of a model cell culture system in which to study early effects of neuropathy-inducing organophosphorus esters. 153 77

Four nerve agents and one therapeutic organophosphate (OP) anticholinesterase (anti-ChE) bind to acetylcholine (ACh) receptors, inhibit or modulate binding of radioactive ligands to these receptors, and modify events regulated by them. The affinity of nicotinic (n) ACh receptors of Torpedo electric organs and most muscarinic (m) ACh receptors of rat brain and N1E-115 neuroblastoma cultures for the OP compounds was usually two to three orders of magnitude lower than concentrations required to inhibit 50% (IC-50) of ACh-esterase activity. However, a small population of m-ACh receptors had an affinity as high as that of ACh-esterase for the OP compound. This population is identified by its high-affinity [3H]-cis-methyldioxolane ([3H]-CD) binding. Although sarin, soman, and tabun had no effect, (O-ethyl S[2-(diisopropylamino)ethyl)] methyl phosphonothionate (VX) and echothiophate inhibited competitively the binding of [3H]-quinuclidinyl benzilate ([3H]-QNB) and [3H]-pirenzepine ([3H]-PZ) to m-ACh receptors. However, VX was more potent than echothiophate in inhibiting this binding and 50-fold more potent in inhibiting carbamylcholine (carb)-stimulated [3H]-cGMP synthesis in N1E-115 neuroblastoma cells--both acting as m receptor antagonist. All five OPs inhibited [3H]-CD binding, with IC-50s of 3, 10, 40, 100, and 800 nM for VX, soman, sarin, echothiophate, and tabun, respectively. The OP anticholinesterases also bound to allosteric sites on the n-ACh receptor (identified by inhibition of [3H]-phencyclidine binding), but some bound as well to the receptor's recognition site (identified by inhibition of [125I]-alpha-bungarotoxin binding). Soman and echothiophate in micromolar concentrations acted as partial agonists of the n-ACh receptor and induced receptor desensitization. On the other hand, VX acted as an open channel blocker of the activated receptor and also enhanced receptor desensitization. It is suggested that the toxicity of OP anticholinesterases may include their action on n-ACh as well as m-ACh receptors if their concentrations in circulation rise above micromolar levels. At nanomolar concentrations their toxicity is due mainly to their inhibition of ACh-esterase. However, at these low concentrations, many OP anticholinesterases (eg, VX and soman) may affect a small population of m-ACh receptors, which have a high affinity for CD. Such effects on m-ACh receptors may play an important role in the toxicity of certain OP compounds.
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PMID:Direct actions of organophosphate anticholinesterases on nicotinic and muscarinic acetylcholine receptors. 323 34

Our studies demonstrate that rat anterior pituitary cells (GH3) are capable of synthesizing and secreting tissue kallikrein together with prolactin and growth hormone. The secretion of prolactin and growth hormone in GH3 cells was measured by two newly developed sensitive radioimmunoassays (RIA), using the polyethylene glycol separation technique. In the direct radioimmunoassay for rat tissue kallikrein, using a polyclonal antiserum which recognizes both active and prokallikrein, the GH3 kallikrein displays parallelism with standard curves of rat urinary kallikrein. The production of immunoreactive kallikrein, prolactin, and growth hormone is time-dependent, and the levels after a 72 h incubation in serum-free media are approximately 12.2 +/- 4.4 ng, 272.2 +/- 33.0 ng, and 475.6 +/- 4.8 ng per 10(6) cells per ml (mean +/- SD, n = 3), respectively. In Western blot analyses, a specific monoclonal antibody to tissue kallikrein (V4D11) identifies GH3-secreted kallikrein as a approximately 39,000 Da protein, slightly larger than approximately 38,000 Da kallikreins of submandibular gland, mouse anterior pituitary cells (AtT 20) or rodent neuroblastoma X glioma hybrid cells (NG108). Kallikrein mRNA in GH3 cells was identified in Northern blot analyses, using a tissue kallikrein cDNA probe. In a RIA using a kallikrein monoclonal antibody (V1C3) recognizing only active kallikrein, kallikrein could not be detected in the media incubated up to 48 h with GH3 cells. However, after trypsin treatment, a time-dependent increase of immunoreactive kallikrein (using monoclonal antibody V1C3), Tos-Arg-OMe esterase, and kinin-releasing activities can be measured in the conditioned media. The activated esterase activity was inhibited by aprotinin and by affinity-purified kallikrein monoclonal antibody (V4D11) in a dose-dependent manner. The data indicated that rat anterior pituitary GH3 cells secrete latent tissue kallikrein, which can be converted to active kallikrein by trypsin. These hormonally responsive cells co-synthesize kallikrein with prolactin and growth hormone and provide a model system for studying the regulation of kallikrein gene expression.
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PMID:Identification of latent tissue kallikrein, prolactin and growth hormone secretion in GH3 pituitary cells using modified radioimmunoassays. 336 Feb 6

Mouse neuroblastoma tumors have only the fifth isozyme band (A(4)) of lactate dehydrogenase, whereas this band is missing in the brain which contained four other bands of lactate dehydrogenase. The alpha-esterase isozyme patterns of tumors, kidney, and brain are similar except that there is an additional slowest-moving form of esterase in all tumor tissues. The malate dehydrogenase pattern is not altered in any of the tissues.
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PMID:Esterase, malate, and lactate dehydrogenases activity in murine neuroblastoma. 471 10

Growth inhibitory factor for mouse neuroblastoma cells was detected in the culture medium of fetal rat glioblasts, and was partially purified and characterized. The factor had an apparent molecular weight of 75,000 and an isoelectric point of 5.8, and showed no esterase activity. It possessed the activity to promote morphological differentiation including the formation of neural processes and the inhibition of cell division when tested on mouse neuroblastoma cell lines (Neuro 2a, NS-20Y, and NIE-115). The activity was susceptible to protease digestion and heat treatment. The serum over 25% cancelled the inhibitory activity of this factor. The factor failed to increase the intracellular contents of cAMP and cGMP. It showed no effect on either morphological differentiation or proliferation of glial cell lines, suggesting that under physiological conditions the factor acts specifically on neuronal cells.
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PMID:Inhibition of growth of mouse neuroblastoma cels by protein factor derived from rat glioblasts. 628 Aug 7

T cells from the peripheral blood of a T-cell chronic lymphocytic leukemia (T-CLL) patient, cultured in the presence of interleukin-2 (IL-2), were found to express the p19 structural core protein of the human T-cell leukemia/lymphoma virus (HTLV) and to release type C virus particles. Comparison of the T-CLL cell line with the original leukemic T cells revealed that both the fresh and the proliferating T-CLL cells were pleomorphic cells that showed a convoluted nucleus and formed rosettes with sheep erythrocytes (E-rosettes). They were reactive with the monoclonal antibodies OKT1, OKT4 and OKT11, but not with OKT3, OKT6 or OKT8, indicating that they were mature T cells but that they differed from normal T cells in their lack of reactivity with OKT3. In addition they did not bind peanut agglutinin or OKM-1, and were negative for Epstein-Barr nuclear antigen, surface immunoglobulin, non-specific esterase activity of Fc- or complement receptors. Part of the fresh T-CLL cells reacted with a monoclonal antibody recognizing HLA-DR antigens (p29, 34) (36%) and with anti-Tac (62%), a monoclonal antibody directed at the IL-2 receptor, indicating that the T-CLL cells were partially activated already in vivo. After culture in vitro all proliferating T-CLL cells expressed HLA-DR and Tac antigens. The fresh T-CLL cells were found to be defective in cell-mediated lympholysis (CML) generated in mixed lymphocyte culture (MLC), antibody-dependent cellular cytotoxicity (ADCC) and lectin-dependent cellular cytotoxicity (LDCC). In addition they failed to exhibit natural killer (NK) cell activity against targets that are usually very susceptible to lysis, such as K562, but were able to kill two tumor-derived cell lines, the melanoma NKI-4 and the neuroblastoma CHP-100. The same pattern of selective killing was observed using the proliferating T-CLL cells as effectors, or cloned T-CLL cultures obtained from them by limiting dilution procedures. Therefore, it was concluded that the T-CLL cells represented a clonal expansion of neoplastic T cells that retained their phenotype and cytotoxic properties after culture in vitro.
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PMID:Phenotypic and functional characterization of HTLV positive neoplastic T cells cultured with interleukin-2--I. Retention of morphology, phenotype and selective cytotoxic properties in long term culture. 632 59

At pH 4.1, bovine thrombin reacts rapidly with N-bromo-succinimide to yield modified enzyme containing oxidized tryptophan residue. Both fibrinogen clotting activity and esterase activity are reduced considerably when three moles of tryptophan residues per mole of thrombin are oxidized, but the Michaelis constants for synthetic substrates are not appreciably altered. Reaction of NBS also results in a decrease in the affinity of thrombin for heparin. The dissociation constant for heparin-thrombin complex is increased by 2.6-fold due to the modification of one tryptophan residue. However, the magnitude of the increase in the dissociation constant remains the same for modified enzymes containing approximately two or three oxidized tryptophan residues. The rate constant for the inactivation of thrombin by antithrombin III is increased by 2.5-fold due to the modification of a single tryptophan residue. This increase in rate constant is not further amplified when more than one tryptophan residue is oxidized. In contrast, in the presence of heparin the rate of inactivation of modified and unmodified thrombins by antithrombin III are not significantly different. Thus, the heparin-sensitized inactivation of thrombin by antithrombin III is affected by the modification of one tryptophan residue. Spectrophotometric titrations of the phenolic hydroxyl groups suggest that the structural environments of tyrosyl groups for both unmodified and modified thrombin containing one oxidized tryptophan residue, are similar. The temperature for half loss of catalytic activity of control and NBS-modified thrombin, containing one oxidized tryptophan, are 52 and 51.5 degrees C respectively. It appears that the one tryptophan residue of thrombin is situated at or close to the binding site of heparin.
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PMID:Catalytic and regulatory functions of N-bromosuccinimide-modified bovine thrombin. 652 42

Cholinergic murine neuroblastoma cells, maintained in vitro, were exposed to a low concentration (0.4 micrograms/ml) of adriamycin. Morphologically the treated cells appeared to differentiate. The cell bodies increased in size from an average fixed cell body diameter of 7-13 to 25-40 micrometers, the cells developed long processes, became argyrophilic and the percentage of cells undergoing mitosis decreased relative to controls. Acetylcholine esterase activity increased in the drug-treated cells suggesting induction of differentiation. However, choline acetyltransferase activity and ganglioside composition remained unchanged. In addition, inoculation of mice with 2 x 10(5) viable drug-treated or control cells resulted in all of the mice developing neuroblastoma. No differences were observed in either the rate of tumor development or survival times. These results suggest that neuroblastoma cells may survive adriamycin treatment by becoming 'differentiated', ceasing cell division until conditions favor their undergoing another cell cycle.
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PMID:Biochemical and morphological study of adriamycin-induced changes in murine neuroblastoma cells. 707 39

Murine neuroblastoma cells have been widely used as a model system for neuronal cells as they can be induced to differentiate in culture by various stimuli, such as dibutyryl cyclic AMP (dbcAMP), prostaglandin, and serum starvation. The cells respond with assembly of microtubules, leading to neurite outgrowth, with increased activity of neuronal-specific enzymes, tyrosine hydroxylase, choline acetyltransferase and acetylcholine-esterase, and synthesis of neurotransmitters. The differentiated cells lose tumorigenicity. Cell-to-substratum adhesion is evidently crucial for neurone extension in vitro. Neurite outgrowth is induced by treatments that increase cell-to-substratum adhesion in some neuronal cell cultures. We have now identified the major high molecular weight proteins synthesized and secreted by murine C1300 neuroblastoma cells as fibronectin, laminin and type IV procollagen, of which the latter two were also found to be deposited in pericellular matrix form.
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PMID:Basal lamina glycoproteins are produced by neuroblastoma cells. 743 74


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