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)

Putrescine, the end-product of ornithine decarboxylase (ODC: L-ornithine carboxylyase, EC; 4.1.1.17) action, induces the synthesis of a protein(s), in L1210, neuroblastoma, and H-35 cells as well as in rat liver, which inhibits ODC activity. Spermidine and spermine, distal products of ODC activity, also induce the synthesis of a similar protein in H-35 cells. These ODC-inhibitors are heat-labile, trypsin-sensitive, and their induction is dependent upon protein synthesis. They have short half-lives which range from 18 to 66 min; these half-lives are similar to those of the ODC derived from the same source. They are noncompetitive inhibitors of ODC activity with an apparent molecular weight of 26,500. Each inhibitor crossreacts with the ODC's of the other cells and forms an enzyme-inhibitor complex which is stable during Sephadex chromatography; however, after treatment with ammonium sulfate, enzyme and inhibitor activities can be dissociated and recovered intact from the same column. We propose the name antizyme for proteins whose synthesis is induced by the proximal or distal products of the enzyme they inhibit.
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PMID:Induction of a protein inhibitor to ornithine decarboxylase by the end products of its reaction. 106 59

We have developed a clonal variant, named DF-40, from the N2a mouse neuroblastoma cell line, which has the ornithine decarboxylase (L-ornithine carboxylase, EC 4.1.1.17, ODC) gene amplified. When DF-40 cells were maintained in a simple salt glucose medium (e.g. Earle's blanced salt solution), L-asparagine alone was sufficient to induce a maximal increase in ODC activity. The increase in ODC activity correlated well with an increase in the amount of ODC protein. Northern blot analysis indicated that asparagine caused a 12-15-fold increase in ODC mRNA. The half-life of ODC mRNA induced by asparagine in DF-40 cells changed from more than 8 h to about 25 min upon removal of asparagine from the culture in the presence of actinomycin D. In contrast, asparagine had little or no effect on the rate of transcription of the ODC gene. Pulse labeling of cells for 15 min with [35S]methionine showed a 90-140-fold increase in the synthesis of ODC protein after 4-8 h of incubation with asparagine. The removal of asparagine from the medium resulted in a rapid loss of ODC protein with a half-life as short as 12 min. The presence of asparagine increased the half-life of ODC protein by 3-5-fold when measured in the presence of cycloheximide. Taken together, our data show that asparagine induced ODC gene expression in DF-40 cells, primarily by post-transcriptional stabilization of ODC mRNA. In addition, asparagine specifically stimulated the synthesis and suppressed the degradation of ODC protein.
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PMID:Mechanism of regulation of ornithine decarboxylase gene expression by asparagine in a variant mouse neuroblastoma cell line. 155 4

Differentiation of mouse neuroblastoma cells has been shown to be accompanied by changes in polyamine metabolism and a decrease in polyamine content. We have previously shown that alpha-difluoromethyl ornithine, a suicide inhibitor of ornithine decarboxylase (ODC, EC 4.1.1.17) and suboptimal concentrations of dibutyryl cAMP (0.1 to 0.2 mM) are effective in inducing the differentiation of mouse Neuro-2a (N2a) neuroblastoma cells. Exogenously added putrescine or spermidine can block the action of DFMO and dibutyryl cAMP, suggesting that polyamines may play a regulatory role in neuroblastoma differentiation. We have now isolated from N2a cells a clonal variant line, DF-40, whose ODC gene has been amplified by 40-fold. The DF-40 cells overproduced the ODC enzyme and contained very high levels of putrescine, spermidine and spermine. Treatment of DF-40 cells with dibutyryl cAMP or DFMO/dibutyryl cAMP led to a more than 80% reduction in polyamine content. Such a decrease did not cause the DF-40 cells to differentiate. Polyamine content in the treated DF-40 cells was still comparable or higher than that in the undifferentiated N2a cells. In contrast, serum-deprivation induced full differentiation of DF-40 cells. Levels of polyamine in the differentiated DF-40 cells, however, were also found to be comparable to that in the undifferentiated N2a cells. Exogenously added polyamines could not block the differentiation of DF-40 cells induced by serum-deprivation, suggesting that the action of polyamines in regulating neuroblastoma differentiation may depend on the presence of serum factors.
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PMID:Differentiation of a mouse neuroblastoma variant cell line whose ornithine decarboxylase gene has been amplified. 166 Nov 61

Ciliary neurotrophic factor (CNTF) is a protein supporting the in vitro survival of a characteristic spectrum of embryonic chicken and rat peripheral neurons. High-speed supernatants of extracts from two neuroblastoma (NB) cell lines--the mouse C 1300 N2a and the human IMR 32--mimic the effects of CNTF on identical target neurons. Promotion of survival is dose-dependent with an ED50 of 80 micrograms (IMR 32) and 140 micrograms (C 1300 N2a) of protein per ml and saturable at plateau values for surviving neurons identical to those achieved with purified CNTF. Small amounts of a CNTF-like material are also detectable in medium conditioned by NB cells. The activity is destroyed by heat and trypsin and not blocked by antibodies to (mouse) nerve growth factor. Unlike the neurite-promoting and neuronal-survival modulating agent laminin, it cannot be depleted on poly(L-alpha-ornithine)-coated plastic surfaces. NB IMR 32 cell extracts were electrophoresed using NaDodSO4/PAGE and transferred to nitrocellulose. Ciliary ganglion neurons seeded on the blotting paper in culture medium lacking CNTF ("cell blot") exclusively survive on two distinct bands with apparent molecular masses of 24 and 48 kDa. Twenty-four kilodaltons is the molecular mass of a CNTF purified from rat sciatic nerve. These results suggest that NB cells may contain a CNTF-like protein and provide further evidence that neurons may store neurotrophic factors. Purified (chicken) CNTF failed to affect proliferation and neurite growth of NB cells. The biological relevance of CNTF for NB cells, therefore, remains to be elucidated.
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PMID:Neuroblastoma cells contain a trophic factor sharing biological and molecular properties with ciliary neurotrophic factor. 347 25

A human neuroblastoma cell line (Paju) grew in 10 mM difluoromethyl-ornithine, which at this concentration normally stops the growth of all mammalian cells. Ornithine decarboxylase from Paju was resistant to inhibition in vitro by difluoromethylornithine, and required 10 microM of the compound for 50% inhibition, whereas ornithine decarboxylase from SH-SY5Y cells (another human neuroblastoma) and from rat liver needed only 0.5 microM difluoromethylornithine. Paju ornithine decarboxylase also exhibited a long half-life (over eight hours) in vivo. The half-life of immunoreactive protein was significantly longer than that of the activity. The long half-life of ornithine decarboxylase in Paju cells leads to its accumulation to a specific activity of 2000 nmol/mg of protein per 30 min during rapid growth (the corresponding activity in SH-SY5Y cells was about 2.5). When partially purified ornithine decarboxylase from Paju cells was incubated with rat liver microsomes it was inactivated with a half-life of 75 min. This inactivation was accompanied by a fall in the amount of immunoreactive protein. In the same inactivating system partially purified SH-SY5Y ornithine decarboxylase had a half-life of 38 min and its half-life in vivo was 50 min. The corresponding values for rat liver ornithine decarboxylase were 45 min and 40 min, respectively. Rat liver microsomes also inactivated rat liver adenosylmethionine decarboxylase. These results suggest that Paju ornithine decarboxylase has an altered molecular conformation, rendering it resistant to (i) difluoromethylornithine and (ii) proteolytic degradation both in vivo and in vitro.
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PMID:A human neuroblastoma cell line with a stable ornithine decarboxylase in vivo and in vitro. 391 35

The biochemical properties of polyamine transport system have been studied in detail in NB-15 mouse neuroblastoma cells in culture by measuring the uptake of [14C]putrescine under various experimentally imposed pharmacological conditions. Putrescine uptake in the NB-15 mouse neuroblastoma cells appeared to be a sodium-dependent process. Iso-osmotic displacement of Na+ in the assay medium with either choline or Li+ resulted in a linear decrease of putrescine uptake. Gramicidin, a channel-former ionophore, inhibited putrescine uptake by more than 90% at 20 nM. N-Ethylmaleimide at 5 mM or p-chloromercuribenzene sulfonate at 50 microM completely abolished putrescine uptake. Conversely, oxidized glutathione at 10 mM or 5,5'-dithiobis-(2-nitrobenzoic acid) at 5 microM gave a 1.3-1.4-fold stimulation after a 1-h incubation. This polyamine transport system appeared to be subjected to adaptive regulation. Polyamine antimetabolites such as alpha-difluoromethyl ornithine stimulated putrescine uptake whereas preloading of cells with polyamines inhibited putrescine uptake. Preloading cells with neutral amino acids that belong to sodium-dependent transport System A stimulated putrescine uptake by more than 8-10-fold. These results suggested that the polyamine transport system in NB-15 mouse neuroblastoma cells was sodium dependent and shared some characteristics common to other known sodium-dependent transport systems. These characteristics included (a) sensitivity to ionophores, (b) sensitivity to sulfhydryl reagents, and (c) sensitivity to intracellular contents of substrate molecules. Our data also indicated that polyamine transport may be regulated by transport System A amino acids.
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PMID:Characterization of the polyamine transport system in mouse neuroblastoma cells. Effects of sodium and system A amino acids. 671 20

The minimum requirements for eliciting or enhancing ornithine decarboxylase activity (EC. 4.1.1.17); L-ornithine carboxylase) in neuroblastoma cells incubated in salts-glucose solutions have been investigated. These incubation conditions permit the study of changes in ornithine decarboxylase activity independently of the growth-associated reactions that occur in cell culture media (Chen, K.Y. and Canellakis, E.S. (1977) Proc. Natl, Acad. Sci. U.S.A. 74, 3791-3795). Ornithine decarboxylase activity can be elicited by a variety of asparagine and other amino acid analogs, including alpha-aminoisobutyric acid, that cannot participate in protein synthesis. Of the eleven asparagine analogs tested, alpha-N-CH3-DL-asparagine is the most potent in eliciting ornithine decarboxylase activity and is equivalent to asparagine in this regard. Inclusion of polar groups into the asparagine molecule results in the loss of its ability to elicit ornithine decarboxylase activity. With the use of these analogs and of analogs of other amino acids it is shown that the rapid fall in ornithine decarboxylase activity that is noted following cycloheximide treatment may not be a consequence of the inhibition of protein synthesis. The rapid fall in ornithine decarboxylase activity is primarily due to the removal of the agent that elicits and stabilizes its activity. These results, the finding that alpha-aminoisobutyric acid stimulates ornithine decarboxylase activity and that sodium is required for the stimulation of ornithine decarboxylase activity are discussed in relation to the "A" amino acid transport system.
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PMID:Studies on the role of protein synthesis and of sodium on the regulation of ornithine decarboxylase activity. 711 71

In the present study we investigated uptake of the nitric oxide (NO) synthase inhibitors NG-methyl-L-arginine and NG-nitro-L-arginine by the mouse neuroblastoma x rat glioma hybrid cell line NG108-15. Uptake of NG-methyl-L-arginine was characterized by biphasic kinetics (Km1 = 8 mumol/L, Vmax1 = 0.09 nmol x mg-1 x min-1; Km2 = 229 mumol/L, Vmax2 = 2.9 nmol x mg-1 x min-1) and was inhibited by basic but not by neutral amino acids. Uptake of NG-nitro-L-arginine followed Michaelis-Menten kinetics (Km = 265 mumol/L, Vmax = 12.8 +/- 0.86 nmol x mg-1 x min-1) and was selectively inhibited by aromatic and branched chain amino acids. Further characterization of the transport systems revealed that uptake of NG-methyl-L-arginine is mediated by system y+, whereas systems L and T account for the transport of NG-nitro-L-arginine. In agreement with these data on uptake of the inhibitors, L-lysine and L-ornithine antagonized the inhibitory effects of NG-methyl-L-arginine on bradykinin-induced intracellular cyclic GMP accumulation, whereas L-tryptophan, L-phenylalanine, and L-leucine interfered with the effects of NG-nitro-L-arginine. These data suggest that rates of uptake are limiting for the biological effects of NO synthase inhibitors.
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PMID:Characterization of neuronal amino acid transporters: uptake of nitric oxide synthase inhibitors and implication for their biological effects. 753 32

The molecular events associated with beta-amyloid-induced neuronal injury remain incompletely characterized. Using a substantia nigra/neuroblastoma hybrid cell line (MES 23.5) synthetic beta-amyloid 1-40 induced a time and dose-dependent apoptotic cell death which was characterized by cell shrinkage and fragmentation of DNA, and was inhibited by aurintricarboxylic acid (ATA), and cycloheximide (CHX). Following beta-amyloid 1-40 treatment, cyclic GMP, an index of NO synthesis, was increased in MES 23.5 cells. The NO scavenger hemoglobin, as well as the NO synthase inhibitors NG-monomethyl-L-arginine acetate (L-NMMA) and L-N5-(1-iminoethyl)ornithine hydrochloride (L-NI0) attenuated such increases. These same inhibitors and scavengers also significantly prevented cytotoxicity. beta-Amyloid also induced an early and transient increase in intracellular calcium as monitored with laser scanning confocal microscopy and Fluo-3 imaging. These induced calcium transients could be significantly blocked by the N-methyl-D-aspartic acid (NMDA) receptor antagonist MK-801. Pretreatment with MK-801 or removal of extracellular Ca2+ also reduced beta-amyloid-induced NO production and neurotoxicity. Furthermore, beta-amyloid neurotoxicity was greatly enhanced in the absence of Mg2+ or in the presence of glutamate or NMDA. These data suggest that beta-amyloid can lead to apoptotic cell death through a NO mediated process possibly triggered by Ca2+ entry through activated NMDA-gated channels.
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PMID:Cell death induced by beta-amyloid 1-40 in MES 23.5 hybrid clone: the role of nitric oxide and NMDA-gated channel activation leading to apoptosis. 758 71

Deoxyhpusine synthase catalyzes the conversion of lysine to deoxyhypusine residue on the eukaryotic initiation factor 5A (eIF-5A) precursor using spermidine as the substrate. Subsequent hydroxylation of the deoxyhypusine residue completes hypusine formation on eIF-5A. Polyamines (putrescine, spermidine, and spermine) have been implicated in tumor growth and differentiation. Because deoxyhypusine/hypusine formation is one of the most specific polyamine-dependent biochemical events, we decided to use N1-guanyl-1,7-diaminoheptane (GC7), a potent inhibitor for deoxyhypusine synthase, to assess the role of hypusine formation on tumor growth and differentiation. GC7 suppressed the growth of N2a mouse neuroblastoma cells and DS19 murine erythroleukemia cells at micromolar concentrations. However, within a narrow concentration range, GC7 could promote the differentiation of mouse neuroblastoma cells in the presence of suboptimal amount of dibutyryl cAMP. In contrast, GC7 blocked the differentiation of DS19 cells induced with hexamethylene bisacetamide. Polyamine depletion by difluoromethyl ornithine (DFMO) has previously been shown to promote differentiation of neuroblastoma cells but inhibits erythrodifferentiation. Since our studies demonstrated that GC7 mimics the action of DFMO on tumor differentiation, it is likely that the effect of DFMO on tumor differentiation is mediated by hypusine formation and that GC7 represents a more specific inhibitor that can alter the differentiation program in certain tumor cells.
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PMID:Effects of inhibitors of deoxyhypusine synthase on the differentiation of mouse neuroblastoma and erythroleukemia cells. 869 49


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