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)

We examined the effects of 6-hydroxydopamine (6-OHDA) treatment on the human neuroblastoma cell line SK-N-SH-SY5Y (SY5Y) and the rat pheochromocytoma cell line, PC12. Structural and metabolic integrity was tested by measuring the ability of cells to transport the non-metabolizable amino acid analogue [3H]-alpha-aminoisobutyric acid (AIB). We determined that treatment with 6-OHDA at concentrations of 49 microM and 62 microM inhibited 50% of the AIB uptake in SY5Y and PC12 cells, respectively. Inhibition of AIB uptake was prevented by the addition of catalase, but was not influenced by the addition of 1 mM dopamine. This indicated that cell damage resulted from the generation of H2O2 and was independent of the catecholamine uptake system. Effects directly on the catecholamine uptake system were observed by measuring the uptake of 3H-dopamine. In contrast to the effects on amino acid uptake, dopamine uptake was significantly inhibited by 6-OHDA treatment, and this inhibition was not prevented by the addition of catalase. The results indicate a Ki of 430 microM for inhibition of dopamine uptake by 6-OHDA treatment of PC12 cells. The results are consistent with a competitive irreversible inhibition of the dopamine uptake sites by 6-OHDA or one of its metabolites. Thus, the lack of a catecholamine uptake-dependent cellular toxicity appears to result from the direct inactivation of catecholamine uptake sites. Similarly, the inhibition of dopamine uptake in vivo by 6-OHDA may be explained, at least in part, by direct inactivation of dopamine uptake sites rather than exclusively by intracellular transport and action of 6-OHDA.
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PMID:Competitive irreversible inhibition of dopamine uptake by 6-hydroxydopamine. 845 41

The study of oxygen radical generation and effects during 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) metabolism was undertaken in an in vitro test system. Three neurochemically discrete neuronal cell lines, B50 (cholinergic) and B65 rat cell lines and SKNSH human neuroblastoma (both catecholaminergic), were exposed to MPTP (0-200 microM). Parallel experiments were performed using reagent H2O2, an intermediate which may be generated during MPTP metabolism, to determine whether MPTP and H2O2 had any selectivity of toxicity and whether the mechanisms of cell death were similar. MPTP toxicity was shown to be reduced by monoamine oxidase B inhibitors, pargyline (P < 0.01) and selegiline (P < 0.05), indicating that toxicity was due to metabolism of MPTP rather than the parent compound. Cytotoxicity was also decreased in the presence of antioxidants, most notably in the presence of superoxide dismutase and catalase together (P < 0.01), suggesting that reactive oxygen species (ROS) play a role in MPTP-induced cell death. Attempts to determine the intracellular target for oxidative attack did not identify significant levels of lipid peroxidation products, but did demonstrate nucleoid expansion, possibly the result of double stranded DNA breaks induced by ROS.
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PMID:An investigation into the role of reactive oxygen species in the mechanism of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine toxicity using neuronal cell lines. 845 68

MHC class I molecules are coexpressed with beta 2-microglobulin (beta 2-M) on many somatic cells. However, these proteins are normally not present on cells of the central nervous system (CNS). Cells derived from human neuroblastomas were used as a model for investigating the molecular basis for the paucity of MHC class I and beta 2-M gene expression in neural cells and for the induction of these genes by two cytokines, IFN-gamma, and TNF-alpha. These cytokines independently increased MHC class I and beta 2-M cell surface expression on the neuroblastoma cell lines. IFN-gamma or TNF-alpha also increased MHC class I and beta 2-M steady-state RNA levels and the expression of MHC class I and beta 2-M CAT reporter constructs transiently transfected into the neuroblastoma cell lines, indicating that the cytokines acted by increasing the transcription of these genes. MHC class I and beta 2-M genes share two conserved regulatory elements, an NF kappa B-like site and the IFN consensus sequence, that act as a constitutive enhancer and an IFN-responsive element, respectively. Low MHC class I and beta 2-M gene expression in these cells was accounted for by undetectable to low factor binding activity specific for the above regulatory elements of these genes. TNF-alpha increased factor binding activity specific for the NF kappa B-like elements and IFN-gamma increased factor binding activity specific for the IFN consensus sequence elements of the MHC class I and beta 2-M genes, but not vice versa. Taken together, our results indicated that IFN-gamma and TNF-alpha increased MHC class I and beta 2-M gene expression in the neuroblastoma cell lines by inducing factor binding to the regulatory elements present in both genes.
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PMID:Regulation of MHC class I and beta 2-microglobulin gene expression in human neuronal cells. Factor binding to conserved cis-acting regulatory sequences correlates with expression of the genes. 846 72

The effects of intracellularly generated H2O2 on cell viability, morphology, and biochemical markers of injury have been investigated in a clonal cell line of neuronal origin (140-3, mouse neuroblastoma X rat glioma) as a cell culture model for the role of oxidative stress in the long-term loss of neurons in the brain. The H2O2 was generated from the redox cycling of menadione, or by the oxidation of serotonin catalyzed by monoamine oxidase, to simulate the effect of amine neurotransmitter turnover. Incubation with menadione at concentrations as low as 10 microM for several hours resulted in significant losses of cell viability and altered morphology. Similar effects were evident in the presence of serotonin only after incubation overnight with concentrations > 1 mM. The cytotoxicity of either agent was potentiated by preincubation with specific inhibitors of two enzymes important to cellular antioxidant defenses, 3-amino-1,2,4-triazole for catalase and 1,3-bis(chloromethyl)-1-nitrosourea for glutathione reductase. Activity of another antioxidant enzyme of particular importance to antioxidant defenses in brain, the selenoprotein glutathione peroxidase, was stimulated fourfold by growth of cultures in the presence of sodium selenite as a source of active-site Se for the enzyme. The only effect of the selenite on other functionally coupled antioxidant enzymes was a decrease in activity of superoxide dismutase at concentrations > 200 nM. The selenite substantially protected cells against oxidative stress induced by combinations of menadione, 3-amino-1,2,4-triazole, and 1,3-bis(chloromethyl)-1-nitrosourea, but was only marginally effective with serotonin as a source of oxidative stress. The monoamine oxidase inhibitor pargyline increased cell survival in the presence of serotonin, demonstrating the role of this enzyme in its cytotoxicity. DNA damage (single strand breaks), but not lipid peroxidation, correlated with the cytotoxic effects of menadione.
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PMID:Oxidative stress in a clonal cell line of neuronal origin: effects of antioxidant enzyme modulation. 849 17

We studied heat shock protein (HSP) synthesis by cultured human neuroblastoma cells in response to either hyperthermia or high levels of superoxide anion (oxygen free radical). Both treatment modalities resulted in induced synthesis of the same major HSP species with an additive effect on the latter and on cell growth inhibition upon combined treatments. Exposure to superoxide anion in the presence of the free radical scavenging enzymes, superoxide dismutase and catalase improved cell survival and prevented HSP induction. These findings suggest a common mechanism by which various forms of injury, such as hyperthermia, cause HSP induction, that is, via oxidative stress or increased production of oxygen free radicals. Increased expression of some HSPs has been detected in association with the pathological lesions that characterize some neurodegenerative diseases such as the neurofibrillary tangles of Alzheimer's disease. This, in turn, suggests that chronic oxidative stress may play a role in the pathogenesis of these disorders.
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PMID:Oxygen free radicals as inducers of heat shock protein synthesis in cultured human neuroblastoma cells: relevance to neurodegenerative disease. 849 94

Human polyomavirus JC virus (JCV) is the causative agent of the demyelinating disorder progressive multifocal leukoencephalopathy (PML). In vivo the cellular tropism of JCV has been shown to be very narrow, and replication appears to be essentially restricted to oligodendrocytes. To investigate the detail cellular tropism of JCV, we employed transfection, microinjection and CAT assays using JCV permissive cells, and several non-permissive cell lines. IMR-32 (human neuroblastoma cells) was permissive for IMR-32 adapted JC virus. A431 (human epidermoid carcinoma) and COS-7 (a SV40 transformed African green monkey kidney cell line) were used as non-permissive cells. Employing infection it could be confirmed that the virus proliferated in IMR-32, but not in A431 and COS-7 cells as measured by immunofluorescence methods. However, after microinjection of IMR-32 adapted JCV it could be shown that virus could replicate not only in IMR-32 but also in COS-7 cells. Virus could not be replicated in A431 cells. Using CAT assays the regulatory region of IMR-32 adapted JCV was shown to be active in IMR-32 and COS-7 cells, but inactive in A431 cells. The result suggests that nuclear transcription factors are also determinant of JCV cell tropism in vivo in addition to specific cellular receptors.
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PMID:[Analysis of the cellular tropism of human polyoma JC virus (JCV)]. 854 82

Human manganese-containing superoxide dismutase (MnSOD) is a nuclear encoded mitochondrial protein that scavenges potentially toxic superoxide radicals by dismuting O2- to O2 plus H2O2. To understand the molecular mechanism governing the transcriptional regulation of the human MnSOD gene, I have isolated and sequenced a genomic clone containing the 5' flanking region of the human MnSOD gene. One major transcription start site was mapped by primer extension to a guanine residue 67 base pairs upstream from the translation start site. Eight putative Sp1 binding elements and one AP1 consensus sequence, but no TATA or CAAT box, were found in the promoter region. Furthermore, a series of chimerical/CAT reporter gene constructs were used to transfect human hepatocellular carcinoma(HepG2) human neuroblastoma and human skin fibroblast cell lines to characterize the promoter and regulatory region of the human MnSOD gene. The results show that human MnSOD gene expression is governed by one promoter and that the basic promoter is located between nucleotides -34 and +38. The results also indicate that both positive and negative elements are involved in the regulation of the cell-type specific expression of the human MnSOD gene. The functional studies indicate that the Sp1 binding sites or G+C rich regions play an important role in regulation of expression of the human MnSOD gene in vivo.
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PMID:Characterization of the 5' flanking region of the human MnSOD gene. 860 39

We investigated the regulation of the rat neuron-specific enolase gene using a transient transfection approach. Recent transgenic mouse studies have shown that a 1.8-kb segment of the rat NSE gene 5' flanking region, including the first (noncoding) exon but not the first intron, is able to drive expression of a reporter gene in parallel with endogenous NSE. These data suggest that cis-acting elements responsible for the spatial and temporal pattern of NSE gene expression are located within the proximal 1.8 kb of the 5' flanking sequence. To further investigate this region, we joined the 1.8-kb regulatory cassette to the cat reporter gene and generated a number of constructs in which the flanking sequence was progressively deleted from the 5' end. These constructs were tested by transient transfection into neuronal and nonneuronal cells, followed by an assay for CAT activity. We found that as little as 255 bp of 5' flanking sequence was able to confer cell type-specificity on the reporter gene. Further truncation to 120 bp of 5' sequence resulted in a sharp downregulation of reporter activity in PC12 cells but a significant rise in both Neuro-2A neuroblastoma cells and nonneuronal Ltk- cells, indicating that cis-acting elements controlling the regulation of NSE in Ltk-, Neuro-2A, and PC12 cells may lie within the 135 bp region covered by this deletion. This region contains an AP-2 site and an element similar in sequence and position to a motif identified in the proximal promoter region of the neuron-specific peripherin gene. Reduction to 95 bp of 5' sequence resulted in a slight downregulation of CAT activity in all cell lines tested, and further truncation to 65 bp of 5' sequence caused a universal reduction to background levels of CAT activity, concomitant with the disruption of the basal NSE promoter. Our results show that the 5' flanking region of the NSE gene is capable of conferring cell type-specificity on a heterologous gene in transfected cells and that elements responsible for this are located within the proximal 255 bp.
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PMID:Sequences in the proximal 5' flanking region of the rat neuron-specific enolase (NSE) gene are sufficient for cell type-specific reporter gene expression. 906 16

Enhanced oxidative stress has been suggested to be involved in the degeneration of nigrostriatal dopaminergic neurons in Parkinson's disease. The high turnover rate of dopamine and/or unsequestered dopamine may cause an increase of formation of hydrogen peroxide via either oxidative deamination of dopamine by monoamine oxidase or autoxidation. Hydrogen peroxide would be converted to more toxic hydroxyl free radicals. L-beta-3,4-Dihydroxyphenylalanine hydrochloride (L-DOPA), the most useful drug in the symptomatic treatment of Parkinson's disease, has been considered to possess deteriorating degenerative side-effects. The catecholaminergic neuroblastoma SH-SY5Y cells were chosen to investigate the cytotoxic effect of dopamine and L-DOPA. Both dopamine and L-DOPA were found to be cytotoxic towards SH-SY5Y cells. Such toxic effects were accompanied by an increase of oxidative stress in the cell cultures and could be reversed effectively by catalase and to a lesser extent by superoxide dismutase. The non-enzymatic antioxidants L-ascorbic acid, glutathione, N-acetyl-L-cysteine, but not (+)-alpha-tocopherol, also completely protected SH-SY5Y cells against the cytotoxic effects induced by dopamine and L-DOPA. Antioxidative factors, namely free radical scavengers (including N-tert-butyl-alpha-phenylnitrone, salicylic acid, and D-mannitol) and a strong iron chelator, deferoxamine, however, did not protect the SH-SY5Y cells against dopamine and L-DOPA. The generation of reactive oxygen species and the resulting enhanced oxidative stress was clearly involved in the dopamine- and L-DOPA-induced cytotoxic effects. Hydrogen peroxide played the most important role related to cytotoxicity of dopamine and L-DOPA.
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PMID:Dopamine- and L-beta-3,4-dihydroxyphenylalanine hydrochloride (L-Dopa)-induced cytotoxicity towards catecholaminergic neuroblastoma SH-SY5Y cells. Effects of oxidative stress and antioxidative factors. 906 40

Stimulation of human SH-SY5Y neuroblastoma cells by a muscarinic receptor agonist, carbachol (CCh; 1 mM), elevated levels of free intracellular calcium and subsequently increased the production of reactive oxygen species (ROS). Quinuclidinylbenzilate (QNB) binding increased at 1 h after CCh, but returned back to the control level at 3 h. Production of ROS increased, however, during the 3 h time period. CCh also increased the translocation of protein kinase C (PKC) to the membrane. ROS production was completely blocked by atropine and a PKC inhibitor, Ro 31-8220. These results show that increased ROS production was a result of muscarinic receptor stimulation, and that PKC had an active role in this cellular stimulation. ROS production upon cellular stimulation by CCh was completely inhibited also by superoxide dismutase, and partially by catalase, indicating that the formation of superoxide anion dominated in cholinergic-induced generation of ROS in human neuroblastoma cells. These results also show that muscarinic stimulation causes sustained ROS production in human neuroblastoma cells. The slow increase in ROS production by CCh suggest a stepwise cascade of events leading to oxidative stress with a triggering role of cholinergic muscarinic receptors in this process.
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PMID:Cholinergic-induced production of reactive oxygen species in human neuroblastoma cells. 915 1


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