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)

Dopamine (DA), while an essential neurotransmitter, is also a known neurotoxin that potentially plays an etiologic role in several neurodegenerative diseases. DA metabolism and oxidation readily produce reactive oxygen species (ROS) and DA can also be oxidized to a reactive quinone via spontaneous, enzyme-catalyzed or metal-enhanced reactions. A number of these reactions are cytotoxic, yet the precise mechanisms by which DA leads to cell death remain unknown. In this study, the neuroblastoma cell line, SK-N-SH, was utilized to examine DA toxicity under varying oxidant states. Cells pretreated with the glutathione (GSH)-depleting compound, L-buthionine sulfoximine (L-BSO), exhibited enhanced sensitivity to DA compared to controls (non-GSH-depleted cells). Furthermore, in cells pretreated with L-BSO, the addition of ascorbate (250 microM) afforded significant protection against DA-induced toxicity, while pyruvate (500 microM) had no protective effect. To further characterize the possibility that DA is associated with oxidative stress, additional studies were carried out with manganese (30 microM) as a pro-oxidant. Manganese and DA (200 microM), although not cytotoxic when individually administered to SK-N-SH cells, had a synergistic action on cytotoxicity. Finally, morphological and molecular markers of programmed cell death (apoptosis) were observed in cells treated with DA and L-BSO. These markers included membrane blebbing and internucleosomal DNA fragmentation. These results suggest that DA toxicity is tightly linked to intracellular oxidant/antioxidant levels, and that environmental factors, such as excessive Mn exposure, may modulate cellular sensitivity to DA.
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PMID:Dopamine toxicity in neuroblastoma cells: role of glutathione depletion by L-BSO and apoptosis. 1070 May 89

Vasoactive intestinal peptide (VIP) provides neuroprotection against beta-amyloid toxicity in models of Alzheimer's disease. A superactive analogue, stearyl-Nle17-VIP (SNV) is a 100-fold more potent than VIP. In primary neuronal cultures, VIP protective activity may be mediated by femtomolar-acting glial proteins such as activity-dependent neurotrophic factor (ADNF), activity-dependent neuroprotective protein (ADNP), peptide derivatives ADNF-9 (9aa) and NAP (8aa), respectively. It has been hypothesized that beta-amyloid induces oxidative stress leading to neuronal cell death. Similarly, dopamine and its oxidation products were suggested to trigger dopaminergic nigral cell death in Parkinson's disease. We now examined the possible protective effects of VIP against toxicity of dopamine, 6-hydroxydopamine (6-OHDA) and 1-methyl-4-phenylpyridinium ion (MPP+) in neuronal cultures [rat pheochromocytoma (PC12), human neuroblastoma (SH-SY5Y) and rat cerebellar granular cells]. Remarkably low concentrations of VIP (10(-16)-10(-8) M), ADNF-9 and NAP (10(-18)-10(-10) M) protected against dopamine and 6-OHDA toxicity in PC12 and neuroblastoma cells. VIP (10(-11)-10(-9) M) and SNV (10(-13)-10(-11) M), protected cerebellar granule neurons against 6-OHDA. In contrast, VIP did not rescue neurons from death associated with MPP+. Since dopamine toxicity is linked to the red/ ox state of the cellular glutathione, we investigated neuroprotection in cells depleted of reduced glutathione (GSH). Buthionine sulfoximine (BSO), a selective inhibitor of glutathione synthesis, caused a marked reduction in GSH in neuroblastoma cells and their viability decreased by 70-90%. VIP, SNV or NAP (over a wide concentration range) provided significant neuroprotection against BSO toxicity. These results show that the mechanism of neuroprotection by VIP/SNV/NAP may be mediated through raising cellular resistance against oxidative stress. Our data suggest these compounds as potential lead compounds for protective therapies against Parkinson's disease.
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PMID:Vasoactive intestinal peptide (VIP) prevents neurotoxicity in neuronal cultures: relevance to neuroprotection in Parkinson's disease. 1078 33

Dopamine-beta-hydroxylase (DbetaH) is a copper-containing enzyme that uses molecular oxygen and ascorbate to catalyze the addition of a hydroxyl group on the beta-carbon of dopamine to form norepinephrine. While norepinephrine causes vasoconstriction following reflex sympathetic stimulation, nitric oxide (NO) formation results in vasodilatation via a guanylyl cyclase-dependent mechanism. In this report, we investigated the relationship between NO and DbetaH enzymatic activity. In the initial in vitro experiments, the activity of purified DbetaH was inhibited by the NO donor, diethylamine/NO (DEA/NO), with an IC(50) of 1 mm. The inclusion of either azide or GSH partially restored DbetaH activity, suggesting the involvement of the reactive nitrogen oxide species, N(2)O(3). Treatment of human neuroblastoma cells (SK-N-MC) with diethylamine/NO decreased cellular DbetaH activity without affecting their growth rate and was augmented by the depletion of intracellular GSH. Co-culture of the SK-N-MC cells with interferon-gamma and lipopolysaccharide-activated macrophages, which release NO, also reduced the DbetaH activity in the neuroblastoma cells. Our results are consistent with the hypothesis that nitrosative stress, mediated by N(2)O(3), can result in the inhibition of norepinephrine biosynthesis and may contribute to the regulation of neurotransmission and vasodilatation.
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PMID:Inhibitory effects of nitric oxide and nitrosative stress on dopamine-beta-hydroxylase. 1088 4

The nitric oxide (NO) donor, S-nitroso-N-acetyl-D,L-penicillamine (SNAP), induced differentiation of human neuroblastoma NB69 cells to a dopamine phenotype, as shown by phase-contrast microscopy and tyrosine hydroxylase (TH) immunocytochemistry. NB69 cells were treated with 50 to 750 microM SNAP in serum-free-defined medium for 24 h. SNAP treatment did not increase the number of necrotic or apoptotic cells. However, a decrease in the number of viable cells was observed at 750 microM SNAP. In addition, a decrease in (3)H-thymidine uptake was detected at the highest dose of SNAP. An increase in the antiapoptotic Bcl-2 and Bcl-xL protein levels and a decrease in the proapoptotic Bax and Bcl-xS protein levels were also detected by Western blot analysis after SNAP treatment. At low doses (50-125 microM), SNAP induced an increase in catecholamine levels, (3)H-dopamine uptake, TH activity and monoamine metabolism, while a decrease in all these parameters was observed at high doses (250-750 microM). The TH protein content, analyzed by Western blot, remained unchanged in SNAP-treated cells throughout the range of doses studied, when compared with the control group. SNAP produced a dose-dependent decrease in the glutathione (GSH) content of the culture medium, without altering intracellular GSH. In addition, cGMP levels and nitrite concentration, measured in the supernatant of SNAP-treated cells, increased in a dose-dependent manner, as compared to control levels. The guanylate cyclase inhibitor lH-[1,2, 4]oxadiazolo[4,3a]quinoxaline-l-one (ODQ) did not revert the SNAP-induced effect on (3)H-dopamine uptake to control values. These results suggest that NO, released from SNAP, induces differentiation of NB69 cells and regulates TH protein at the post-transcriptional level through a cGMP-independent mechanism.
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PMID:Nitric oxide induces differentiation in the NB69 human catecholamine-rich cell line. 1096 52

Redox changes within neurones are increasingly being implicated as an important causative agent in brain ageing and neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD) and Alzheimer's disease (AD). Cells have developed a number of defensive mechanisms to maintain intracellular redox homeostasis, including the glutathione (GSH) system and antioxidant enzymes. Here we examine the effects of N-acetyl-L-cysteine (NAC) on beta-amyloid (A beta) secretion and tau phosphorylation in SHSY5Y neuroblastoma cells after exposure to oxidative stress inducing/cytotoxic compounds (H(2)O(2), UV light and toxic A beta peptides). A beta and tau protein are hallmark molecules in the pathology of AD while the stress factors are implicated in the aetiology of AD. The results show that H(2)O(2), UV light, A beta 1-42 and toxic A beta 25-35, but not the inactive A beta 35-25, produce a significant induction of oxidative stress and cell cytotoxicity. The effects are reversed when cells are pre-treated with 30 mM NAC. Cells exposed to H(2)O(2), UV light and A beta 25-35, but not A beta 35-25, secrete significantly higher amounts of A beta 1-40 and A beta 1-42 into the culture medium. NAC pre-treatment increased the release of A beta 1-40 compared with controls and potentiated the release of both A beta 1-40 and A beta 1-42 in A beta 25-35-treated cells. Tau phosphorylation was markedly reduced by H(2)O(2) and UV light but increased by A beta 25-35. NAC strongly lowered phospho-tau levels in the presence or absence of stress treatment.
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PMID:N-acetyl-L-cysteine protects SHSY5Y neuroblastoma cells from oxidative stress and cell cytotoxicity: effects on beta-amyloid secretion and tau phosphorylation. 1114 96

In the present study, the protective effects of Danchunhwan on the cytotoxicity by peroxynitrite and nitric oxide (NO) were investigated in human dopaminergic neuroblastoma SH-SYSY cells. Danchunhwan has been used to treat infarction and cerebrovascular diseases in Oriental medicine for centuries. Cells were pretreated with Danchunhwan and exposed to sodium nitroprusside (SNP), an NO donor, and 3-morpholinosydnonimine (SIN-1) which simultaneously generates NO and superoxide, thus possibly forming peroxynitrite. Exposure of cells to SIN-1 for 24 hr induced 75% of apoptotic cell death, as evaluated by ladder-pattern fragmentation of genomic DNA and characteristic of apoptosis using 4', 6-diamidino-2-phenylinol (DAPI). However, pretreatment of SH-SY5Y cells with Danchunhwan inhibited the apoptotic cell death in a dose-dependent manner. Even though Danchunhwan was washed out after preincubation for 12 hr, cells were still remained to be resistant against cytotoxicity of SIN-1. It also inhibited SIN-1-induced activation of caspase 3-like protease in a dose-dependent fashion. Furthermore, Danchunhwan recovered the levels of intracellular antioxidant system, reduced glutathione (GSH) (83%), which was decreased by the addition of SIN-1 (63%). Taken together, we suggest that Danchunhwan protects human neuroblastoma SH-SY5Y cells from apoptotic death by free radicals including peroxynitrite and NO via generation of antioxidant, GSH.
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PMID:Danchunhwan water extract prevents apoptotic death by peroxynitrite and nitric oxide in human dopaminergic neuroblastoma SH-SY5Y cells. 1141 51

Neurotoxic effects of methylmercury, were investigated in vitro in primary cultures of human neurons and astrocytes isolatedfrom human fetal brain and in the human neuroblastoma cell line SH-SY5Y. The protection provided by agents with antioxidant properties was tested in these cultures to examine the oxidative stress mechanism of methylmercury poisoning. After 24 h of exposure to methylmercury, LC50 values were 6.5, 8.1 and 6.9 microM for human neurons, astrocytes and neuroblastoma cells, respectively, and the degree of cell damage increased at longer exposure times. Depletion of the cellular pool of reduced glutathione (GSH) by treatment with buthionine sulfoximine potentiated methylmercury cytotoxicity in all three cell types; neuroblastoma cells were the most sensitive. Addition of GSH extracellularly blocked methylmercury neurotoxicity in all cell types. The major beneficial effect of GSH could be attributed to its capacity to form conjugates with methylmercury, which reduces the availability of these organometallic molecules to the cells and facilitates their efflux. Cysteine protected astrocytes and neuroblastoma cells from methylmercury neurotoxicity, while selenite, Vitamin E and catalase produced some minor protective effects in three cell types, particularly in neurons. The present study showed that the human neural cells tested had differential responses to methylmercury: astrocytes were resistant to methylmercury neurotoxicity and neurons were more most responsive to protection afforded by antioxidants among the three cell types.
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PMID:Methylmercury neurotoxicity in cultures of human neurons, astrocytes, neuroblastoma cells. 1145 33

Oxidative stress elicits an adaptive antioxidant response, which varies with tissue type. Diquat, a potent redox cycler that generates reactive oxygen species, has been used to study oxidative stress; however, its effect on the antioxidant system has not been characterized in neuronal cells. Accordingly, we measured antioxidant parameters and cell growth in human neuroblastoma SH-SY5Y cells cultured for 48 h in medium containing 5, 10, or 25 microM diquat dibromide or phosphate-buffered saline. Viable cells were assayed for glutathione (GSH) and activities of catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR), glutathione peroxidase (GPX), and glucose-6-phosphate dehydrogenase (GPDH). Mitochondrial function was evaluated by glutamate dehydrogenase (GDH) activity and MTT reduction. Diquat caused a marked concentration-related decrease in viable cell count ( by 26, 51, and 87% at 5, 10, and 25 microM diquat). Cell viability was only affected at 10 and 25 microM diquat and did not fully account for the decreased viable cell count. Concentration-related increases also occurred with GSH levels and a majority of antioxidant enzymes activities; however, the mode and magnitude varied with parameter. Increases in GSH, CAT, SOD, and GR were maximal at 25 microM diquat (to 3-, 6-, 2-, and 1.5-fold control values, respectively). GPDH activity was maximal at 10 microM diquat and then decreased to 86% of control activity at 25 microM diquat. GPX activity showed a concentration-related decrease (to 35% of control). Activity of the mitochondrial enzyme GDH increased 3-fold at 25 microM diquat, along with a lesser increase in MTT reduction. We conclude that diquat reduces cell growth in neuroblastoma cells and induces an adaptive antioxidant response, which are concentration dependent and occur at sublethal concentrations. At higher concentrations, diquat alters mitochondrial function and becomes increasingly toxic.
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PMID:Effect of diquat on the antioxidant system and cell growth in human neuroblastoma cells. 1181 26

Preconditioning adaptation induced by transient ischemia can increase brain tolerance to oxidative stress, but the underlying neuroprotective mechanisms are not fully understood. Recently, we developed a human brain-derived cell model to investigate preconditioning mechanism in SH-SY5Y neuroblastoma cells.(1) Our results demonstrate that a non-lethal serum deprivation-stress for 2 h (preconditioning stress) enhanced the tolerance to a subsequent lethal oxidative stress (24 h serum deprivation) and also to 1-methyl-4-phenyl-pyridinium (MPP(+)).(2) Two-hour non-lethal preconditioning stress increased the expression of neuronal nitric oxide (NOS1/nNOS) mRNA, Fos, Ref-1, NOS protein, and then nitric oxide (*NO) production. As well as MnSOD expression, the *NO-cGMP-PKG pathway mediated the preconditioning-induced upregulation of antiapoptotic protein Bcl-2 and the downregulation of adaptor protein p66(shc). We also propose that cGMP-mediated preconditioning-induced adaptation against oxidative stress may be due to the synthesis of a new protein, such as thioredoxin (Trx) since the protective effect can be blocked by Trx reductase inhibitor.(3) The antioxidative potency of Trx was approximately 100 and 1,000 times greater than GSNO and GSH, respectively. These results suggest that *NO-cGMP-PKG signaling pathway plays an important role in the preconditioning-induced neuroprotection, and perhaps cardioprotection, against oxidative stress.
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PMID:Preconditioning-mediated neuroprotection: role of nitric oxide, cGMP, and new protein expression. 1207 58

Tetrandrine (TET), a plant alkaloid, is known primarily as a non-selective Ca(2+) channel blocker. On the contrary to the cytoprotective effect on ischemia/reperfusion injury, TET has also been reported to cause cytotoxicity. In this study, we wished to understand the apparently disparate effects of this potential drug and thus investigated molecular mechanisms on proliferation and apoptosis and its effect on oxidative stress-induced apoptosis in Neuro 2a mouse neuroblastoma cells. We showed that TET, at high concentrations, induced cell cycle arrest and apoptosis through oxidative stress with following observations. Firstly, 10 microM TET elevated the reactive oxygen species (ROS) level and accordingly depleted glutathione (GSH) content. Secondly, pretreatment with antioxidants (NAC or GSH) protected cells from TET-induced apoptosis. We also demonstrated that treatment with 10 microM TET caused not only induction of p53, p21(waf1), and Bax, but also nuclear translocation of p53 and hypo-phosphorylation of pRb concurrently. Our important finding is that the concentration-dependent dual effect of TET, either inhibiting or promoting cell death induced by H(2)O(2) was observed, probably through regulating redox balance, which was well reflected on the GSH content in each condition. Besides, inhibition of Ca(2+) influx protected cells from H(2)O(2)-induced apoptosis even in the presence of 10 microM TET. Taken together, our data suggest that TET regulation of cellular redox states may play a major role in its dual action of cytotoxicity and cytoprotection.
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PMID:Tetrandrine cytotoxicity and its dual effect on oxidative stress-induced apoptosis through modulating cellular redox states in Neuro 2a mouse neuroblastoma cells. 1217 98


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