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)

Retinoic acid is a naturally occurring metabolite of vitamin A that influences the differentiation of a variety of neural cells in vitro. In the LA-N-1 human neuroblastoma line, retinoic acid treatment increases the binding of nerve growth factor (Bmax). The purpose of this study was to examine the effects of retinoic acid on PC12 rat pheochromocytoma, a neural crest-derived cell line that can be induced to express a sympathetic neuroblast-like phenotype by nerve growth factor treatment. In contrast to the differentiating effects of nerve growth factor, retinoic acid treatment of PC12 cells had a negligible effect on cellular morphology. However, treatment with retinoic acid enhanced the survival of PC12 cells following oxidative injury generated by H2O2 treatment in a manner that is qualitatively similar to that observed after nerve growth factor treatment. Also, there was an increase in 125I-nerve growth factor binding activity in solubilized PC12 membrane preparations derived from retinoic acid-treated PC12 cells. These data suggest that retinoic acid may play a role in neuronal development and in neuronal injury by stimulating the ability of neurons to cope with oxidative stress and/or by enhancing neuronal responsiveness to trophic factors such as the nerve growth factor.
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PMID:Antioxidant effect of retinoic acid on PC12 rat pheochromocytoma. 164 45

This study evaluates the role of N-hydroxylamine (NH2OH) in activating soluble guanylate cyclase in the mouse neuroblastoma clone N1E-115. It has been proposed that NH2OH is a putative intermediate in the biochemical pathway for the generation of nitric oxide (NO)/endothelium-derived relaxing factor (EDRF) from L-arginine. NH2OH caused a time- and concentration-dependent increase in cyclic GMP formation in intact cells. This response was not dependent on Ca2+. In cytosol preparations the activation of guanylate cyclase by L-arginine was dose-dependent and required Ca2+ and NADPH. In contrast, NH2OH itself did not activate cytosolic guanylate cyclase but it inhibited the basal activity of this enzyme in a concentration-dependent manner. The formation of cyclic GMP in the cytosolic fractions in response to NH2OH required the addition of catalase and H2O2. On the other hand, catalase and/or H2O2 lead to a decrease in L-arginine-induced cyclic GMP formation. Furthermore, NH2OH inhibited L-arginine- and sodium nitroprusside-induced cyclic GMP formation in the cytosol. The inhibition of L-arginine-induced cyclic GMP formation in the cytosol by NH2OH was not reversed by the addition of superoxide dismutase. These data strongly suggest that NH2OH is not a putative intermediate in the metabolism of L-arginine to an activator of guanylate cyclase.
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PMID:N-hydroxylamine is not an intermediate in the conversion of L-arginine to an activator of soluble guanylate cyclase in neuroblastoma N1E-115 cells. 167 45

Neuroblastoma cells accumulate ascorbic acid and iron. It was hypothesized that these features could be exploited for sensitizing neuroblastoma cells for therapy in combination with reactive oxygen intermediates. In the present study the effects of 6-hydroxydopamine (6-OHDA) and H2O2 on metabolic parameters critical for cell survival were investigated in cells with low and high ferritin content in the presence and absence of ascorbate. Human neuroblastoma SK-N-SH cells were pretreated with 100 microM FeSO4 and 10 microM desferrioxamine, respectively, for 24 h yielding cells with different ferritin contents. The effects of 6-OHDA and H2O2 (25 microM-250 microM) in the absence and presence of 1 mM ascorbic acid on DNA strand break formation, activation of poly(ADP-ribose) polymerase, and finally decrease in NAD+ and ATP concentration were investigated. All these parameters were influenced by 6-OHDA and H2O2 in a concentration-dependent manner in a similar way. The effects were most pronounced in ferritin-rich cells and in the presence of ascorbic acid. Using isolated CCC PM2 DNA, 6-OHDA and ascorbic acid caused strand breaks that were prevented in the presence of mannitol or desferrithiocine. H2O2-mediated strand breaks were observed only in the presence of ascorbic acid. Based on these data and data published by others a model explaining the deleterious effects of ascorbic acid on neuroblastoma cells is presented. It is suggested that continuous application of a high dosage of ascorbic acid might be a useful approach in neuroblastoma therapy.
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PMID:Ascorbic acid enhances the effects of 6-hydroxydopamine and H2O2 on iron-dependent DNA strand breaks and related processes in the neuroblastoma cell line SK-N-SH. 193 70

Because of the important biological functions of peroxidases, there is growing interest in the measurement of their concentrations in various secretions. At present, there is no standard method which allows for comparisons in reported activities. This report describes procedures which can be used to measure peroxidase enzyme concentrations by commonly employed assays. Regression equations have been determined which can be used to calculate concentrations of bovine lactoperoxidase (LPO), human salivary peroxidase (SPO), and human myeloperoxidase (MPO) from activities measured with the following donors: pyrogallol, guaiacol, 2,2'-azinobis(3-ethylbenzylthiazoline-6-sulfonic acid), and thiocyanate (SCN-). The peroxidation rates of these donors depend upon the concentrations of hydrogen peroxide (H2O2) used in the individual assays and thus, for accurate, reproducible results, these concentrations must be carefully controlled. The SCN- normally present in human saliva will reduce observed reaction rates by simple competition kinetics in the ABTS, guaiacol and pyrogallol assays and will increase the rates observed when Cl- is used as a donor in NBS assay for MPO. Therefore, SCN- must be removed from saliva samples prior to peroxidase activity determination by all assays except the thionitrobenzoic acid (NBS) assay. LPO cannot be used as a standard for either SPO or MPO because the specific activities of LPO, SPO, and MPO are significantly different.
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PMID:Quantitative, standardized assays for determining the concentrations of bovine lactoperoxidase, human salivary peroxidase, and human myeloperoxidase. 196 65

6-Hydroxydopamine(6-OHDA) and Merocyanine-540(MC-540) have been used clinically for purging of neuroblastoma cells prior to autologous bone marrow transplantation. Both substances were found to be more toxic against neuroblastoma cells than against hematopoietic stem cells. The more pronounced cytotoxic effects of 6-OHDA against neuroblastoma cells were not caused by its selective uptake; the rapid autooxidation at physiological pH leads to the formation of H2O2 already in the incubation medium. Cytotoxic effects were not detected in short-time test systems (4 hour chromium-51 release assay) but only after longer incubation periods. In contrast, MC-540 proved to be toxic almost equally in short- and long-time test systems. 4-Hydroxynonenal(4-HNE) that may be formed in the plasma membrane subsequently to photoactivation of MC-540 was only slightly more toxic to neuroblastoma cells than to hematopoietic cells. Although the use of 6-OHDA and MC-540 in bone marrow purging has some limitations, the sensitivity of neuroblastoma cells against reactive oxygen compounds may be exploited more generally for therapy of this tumor.
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PMID:Cytotoxic effects of 6-hydroxydopamine, merocyanine-540 and related compounds on human neuroblastoma and hematopoietic stem cells. 251 Oct 86

Quantification of nickel in animal soft tissue is of toxicological interest. A digestion method applying the use of microwave ovens for irradiating samples in Teflon digesters was developed. An acid mixture containing nitric acid (16 M, 1.0 ml g-1 tissue), hydrochloric acid (6 M, 0.5 ml g-1 tissue) and H2O2 (30%, 1.0 ml g-1 tissue) and irradiation at 600 W for 5 min were required for complete dissolution of tissue matrices and nickel compounds. Analyses of Ni in National Bureau of Standards Reference Material 1566 oyster tissue gave 0.87 +/- 0.24 micrograms g 1(mean +/- SD, n = 5), which was in agreement with the NBS certified value of 1.03 +/- 0.19 micrograms g-1. Recoveries of 1-300 micrograms Ni added as nickel sulfate (highly soluble), nickel subsulfide (moderately soluble in biological fluids and acid) or nickel oxide (green high-temperature oxide, low solubility in biological fluids and acid) to lung, liver, lymph node and kidney were quantitative, except in the case of nickel sulfate added to kidney, where recovery was less than quantitative for 1-10 micrograms Ni. The method appears effective for digestion of a variety of tissues requiring Ni analyses.
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PMID:A rapid digestion method for analysis of nickel compounds in tissue by electrothermal atomic absorption spectrometry. 277 54

6-Hydroxydopamine(6-OHDA), a specific neurotoxin against sympathetic nerve cells, is a drug already used for purging of bone marrow from neuroblastoma cells before autologous bone marrow transplantation. However, we could not detect significant differences in the toxicity of 6-OHDA against neuroblastoma and other tumor cells under the purging conditions clinically used. In contrast, bone marrow stem cells were much more resistant. The unspecific toxic effect of 6-OHDA is caused by H2O2 or H2O2-derived products which are generated by auto-oxidation in the incubation medium before a significant amount of 6-OHDA is taken up by the cells. Withdrawal of oxygen during the incubation period and subsequent incubation with an oxygen containing medium led to a more specific destruction of neuroblastoma cells which can take up 6-OHDA selectively.
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PMID:The role of reactive oxygen compounds derived from 6-hydroxydopamine for bone marrow purging from neuroblastoma cells. 299 60

We have isolated a heme protein from canine midbrains that possesses potent peroxidase activity. This enzyme catalyzes the oxidation of dopamine to neuromelanin in the presence of H2O2. We have further shown that the isolated peroxidase possesses potent cytotoxic activity in the presence of superoxide or H2O2 and Cl-. The enzyme possesses an endogenous NAD(P)H oxidase activity that can promote the cytotoxic activity by virtue of its production of superoxide. Other enzymes such as dihydroorotate dehydrogenase and galactose oxidase, which produce O2- and H2O2, respectively, are also effective in promoting the cytotoxic activity of the brainstem peroxidase. Although rat erythrocytes were routinely used as the target cell, other cell types, including rat hepatoma and mouse neuroblastoma cells, are also susceptible to the toxic action of the peroxidase. The cytotoxic action of the brainstem peroxidase is dramatically enhanced by kainic acid and is significantly enhanced by Mn2+, whereas dopamine was found to be a potent inhibitor of the cytotoxic activity. Based on these findings, we postulate a central role for the brainstem peroxidase in dopamine metabolism as well as in the biochemical and anatomical changes associated with Parkinson's disease.
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PMID:Neuromelanogenic and cytotoxic properties of canine brainstem peroxidase. 302 61

Resistance of human neuroblastoma cell line SK-N-SH-SY5Y (SY5Y) to the neurotoxin 6-hydroxydopamine (6-OHDA) was established by exposure of the cells to nerve growth factor (NGF). SY5Y cells display several properties of immature sympathetic nerve cells, including morphological responses to nerve growth factor and susceptibility to cytolysis by 6-OHDA. High resistance to 6-OHDA was achieved by culturing SY5Y cells with NGF. Protection persisted when NGF was absent for 24 h or when cells were treated with colcemid. In contrast, dibutyryl cyclic AMP did not stimulate resistance to 6-OHDA. NGF-treated cells were also resistant to H2O2, a toxic product of 6-OHDA autoxidation.
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PMID:Stimulation of resistance to 6-hydroxydopamine in a human neuroblastoma cell line by nerve growth factor. 627 67

5-S-Cysteinyldopa, a melanin precursor, has been shown to possess selective toxicity to tumour cells in vitro and in vivo. The mechanism of cytotoxicity of the catechol was studied in comparison with L-dopa and 5-S-cysteaminyldopamine. Growth inhibition of human neuroblastoma cell line of YT-nu by 5-S-cysteinyldopa was completely depressed by addition of catalase. Superoxide dismutase and five drugs thought to scavenge hydroxyl radicals or quench singlet oxygen had little effect on the cytotoxicity. Hydrogen peroxide itself was also cytotoxic at low concns. These results indicated that hydrogen peroxide was a mediator of the cytotoxicity of 5-S-cysteinyldopa. It is suggested that reaction of the catechol with cellular superoxide radicals contributes to the production of hydrogen peroxide in addition to autoxidation. Catalase reduced the cytotoxicity of L-dopa by half, while it had no inhibitory effect on the strong cytotoxicity of 5-S-cysteaminyldopamine.
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PMID:The mechanism of toxicity of 5-S-cysteinyldopa to tumour cells. Hydrogen peroxide as a mediator of cytotoxicity. 640 13


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