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)

Melanocortins (MC), neuropeptides derived from pro-opiomelanocortin, have been implicated in enhancing neurite outgrowth via an as yet unknown mechanism. Recently, five MC receptors have been identified, three of which, the MC3-R, the MC4-R and the MC5-R, are expressed in the nervous system. In this study, alpha-MSH and the melanocortin analog [D-Phe7]ACTH (4-10) were able to stimulate neurite outgrowth in the neuroblastoma cell line Neuro 2A. ACTH (4-10), gamma2-MSH and ORG2766 were inactive. In addition, the MC4-R antagonist [D-Arg8]ACTH (4-10), inhibited the alpha-MSH effect, indicating that the MC4-R mediated stimulation of neurite outgrowth by alpha-MSH. Indeed, the presence of MC4-R mRNA in Neuro 2A cells was demonstrated by a RNase protection assay. Heterologous expression of the MC5-R in Neuro 2A cells lead to the recruitment of a responsiveness to gamma2-MSH, but did not increase the effect of alpha-MSH on neurite outgrowth. This finding indicated that the function of MC4-R can also be exerted by another MC receptor, suggesting that the coupling to Gs, which they have in common, plays an essential role in the neurite outgrowth promoting effect. This was further substantiated by the fact that forskolin treatment per se induced neurite outgrowth in a similar fashion. These data imply that the neurotrophic properties of alpha-MSH are likely to result from Gs-coupled MC receptor activity in neuronal cells.
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PMID:Melanocortin receptors mediate alpha-MSH-induced stimulation of neurite outgrowth in neuro 2A cells. 901 63

It is now clearly established that alpha-2 adrenergic receptors can be subdivided in three pharmacological subtypes (alpha-2A, alpha-2B and alpha-2C) encoded by distinct genes (alpha 2C10, alpha 2C2 and alpha 2C4, respectively, in humans). Whereas the study of the regulation of the human alpha-2A adrenergic receptor and of the promoter region of the alpha 2C10 gene has being greatly helped by the availability of the colon carcinoma cell line HT29, the study of the other human receptor subtypes has thus far been limited to homologous desensitization/down-regulation in transfected cells, because of the lack of human cellular models constitutively-expressing alpha-2B or alpha-2C adrenergic receptors. Several human cell lines were thus screened, in an attempt to find such models. Radioligand binding studies with [3H]RX821002 and [3H]MK912, reverse transcription-polymerase chain reactions and RNase mapping experiments with pairs of primers and riboprobes specific for each subtype demonstrated that the hepatoma cell line HepG2 and the neuroblastoma cell line SK-N-MC possess alpha-2 adrenergic receptors of the alpha-2C subtype. However, whereas HepG2 expresses exclusively alpha-2C receptors (55 +/- 7 fmol of [3H]MK912 binding sites/mg of protein), SK-N-MC expresses both alpha-2A and alpha-2C subtypes in fairly similar amounts (20 +/- 8 and 23 +/- 3 fmol of [3H]MK912 binding sites/mg of protein, respectively). The study of the inhibition of 3H-labeled antagonist binding by UK14304 demonstrated that a fraction of the receptor population was coupled to pertussis toxin-sensitive G-proteins, which were identified as Gi2 and Gi3 by immunoblotting. The alpha-2 agonist was, moreover, able to decrease forskolin-stimulated cAMP production by 47% in HepG2 and 23% in SK-N-MC, demonstrating that inhibition of adenylyl cyclase is one of the primary mechanisms of signal transduction in both cell lines. HepG2 and SK-N-MC are the first human cell lines unquestionably shown to natively express alpha-2C adrenergic receptors. The discovery of these two models may be useful for future study of the regulation of alpha 2C4 gene expression in cells of different origins and investigation of the reciprocal regulation of alpha-2A and alpha-2C subtype in single cells.
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PMID:HepG2 and SK-N-MC: two human models to study alpha-2 adrenergic receptors of the alpha-2C subtype. 915 9

NADH-dichlorophenol-indophenol oxidoreductases (PMOs) were purified from synaptic plasma membranes or synaptic vesicles (small recycling vesicles) from both bovine and rat brains and from a neuroblastoma cell line, NB41A3. Several isoforms could be identified in purified plasma membranes and vesicles. Purification of the enzyme activity involved protein extraction with detergents, (NH4)2SO4 precipitation, chromatography under stringent conditions and native PAGE. PMO activity could be attributed to a very tight complex of several proteins that could not be separated except by SDS/PAGE. SDS/PAGE resolved the purified complex into at least five proteins, which could be micro-sequenced and identified unambiguously as hsc70, TOAD64 and glyceraldehyde-3-phosphate dehydrogenase tightly associated with the brain-specific proteins aldolase C and enolase-gamma. Enzyme activity could be purified from both synaptic plasma membranes and recycling vesicles, yields being much greater from the latter source. Highly purified plasma membranes (prepared from a neuroblastoma cell line NB41A3 by iminobiotinylation of intact cells and affinity purification with avidin and anti-avidin antibodies under very stringent conditions) also displayed PMO activity tightly associated with TOAD64. The association of PMO in a tight complex was confirmed by its immunoprecipitation from cellular and membrane extracts of NB41A3 using antibodies directed against any component protein of the complex followed by immunodetection with antibodies directed against the other members. Antibodies also inhibited the enzyme activity synergistically. In addition, induction of the different components of the complex during dichlorophenol-indophenol stress was demonstrated by the S1 RNase-protection assay in synchronized NB41A3 cells. The role of the complex in membrane fusion and cellular response to extracellular oxidative stress during growth and development is discussed.
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PMID:Purification of a dichlorophenol-indophenol oxidoreductase from rat and bovine synaptic membranes: tight complex association of a glyceraldehyde-3-phosphate dehydrogenase isoform, TOAD64, enolase-gamma and aldolase C. 918 18

The m1 receptor is one of five muscarinic receptors that mediate the metabotropic actions of acetylcholine in the nervous system where it is expressed predominantly in the telencephalon and autonomic ganglia. RNase protection, primer extension, and 5'-rapid amplification of cDNA ends analysis of a rat cosmid clone containing the entire m1 gene demonstrated that the rat m1 gene consists of a single 657-base pairs (bp) non-coding exon separated by a 13. 5-kilobase (kb) intron from a 2.54-kb coding exon that contains the entire open reading frame. The splice acceptor for the coding exon starting at -71 bp relative to the adenine of the initiating methionine. This genomic structure is similar to that of the m4 gene (Wood, I. C., Roopra, A., Harrington, C. A., and Buckley, N. J. (1995) J. Biol. Chem. 270, 30933-30940 and Wood, I. C., Roopra, A., and Buckley, N. J. (1996) J. Biol. Chem. 271, 14221-14225). Like the m4 gene, the m1 promoter lacks TATA and CAAT consensus motifs, and the first exon and 5'-flanking region are not gc-rich. The 5'-flanking region also contains the consensus regulatory elements Sp-1, NZF-1, AP-1, AP-2, E-box, NFkappaB, and Oct-1. Unike the m4 promoter, there is no evidence of a RE1/NRSE silencer element in the m1 promoter. Deletional analysis and transient transfection assays demonstrates that reporter constructs containing 0.9 kb of 5'-flanking sequence and the first exon are sufficient to drive cell-specific expression of reporter gene in IMR32 neuroblastoma cells while remaining silent in 3T3 fibrobasts.
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PMID:Structure of the m1 muscarinic acetylcholine receptor gene and its promoter. 920 29

Neuroblastoma cells are thought to depend upon autocrine stimulation by IGF-II but not by IGF-I. We have studied the expression of IGF, IGFBP and IGF receptor mRNA in two human neuroblastoma cell lines, SK-N-MC and CHP, and asked whether or not the expression of the IGF system in these malignant cells determines their growth pattern. SK-N-MC cells grow with a cell doubling time of 36 hours in medium supplemented with 10% fetal calf serum whereas CHP cells only grow with a doubling time of 72 h. In addition, the SK-N-MC cell line has a plating efficiency ten times greater than the CHP cell line. RNase protection assays were performed using (32)P-labelled riboprobes and RNA that had been purified from SK-N-MC and CHP cells respectively. A 520 bases human IGF-I, a 556 bases human IGF-II, a 480 bases human IGF-I receptor and a 250 human IGF-II/mannose-6-phosphate (M6P) receptor probe were radiolabelled as were human IGFBP-1, -2, -3, -4, -5 and -6 probes. While both SKNMC and CHP neuroblastoma cells expressed mRNAs for IGFBP-2, -4, and -6 no signal was detected for IGFBP-1, and -3 and only SK-N-MC cells expressed IGFBP-5 mRNA. In addition, a 400 bases protected band was seen with the IGF-I receptor probe and a 260 bases protected band with the IGF-IIM6P receptor probe in either cell line. Interestingly, a 300 bases protected species was detected with the IGF-II probe in CHP cell RNA whereas SK-N-MC cells did not express IGF-II transcripts. Conversely, SK-N-MC cells expressed a 520 bases IGF-I transcript while CHP cells did not show IGF-I mRNA expression. As determined by specific radioimmunoassays SK-N-MC cells secreted 0.75+/-0.02 ng/ml IGF-I, 1.2+/-0.04 ng/ml IGF-II and 149+/-2.1 ng/ml IGFBP-2 within 24 h, whereas CHP cells secreted 0.1+/-0.01 ng/ml IGF-I, but 6.2+/-0.1ng/ml IGF-II and 254.8+/-5.5 ng/ml IGFBP-2 (N=5). IGFBP-2 secretion correlated positively with IGF-II secretion in CHP cells (r=0.85, P=0.05) and negatively with IGF-I (r= -0.9, P<0.01) in SK-N-MC cells. In conclusion, SK-N-MC cells which grow rapidly and have a high plating efficiency, express IGF-I, while CHP cells that grow more slowly express IGF-II. We hypothesize that neuroblastoma cells depend upon autocrine stimulation by either IGF-I or IGF-II. Variable sensitivity to growth inhibitors or apoptotic processes may be related to the differential expression of the IGF system.
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PMID:Human neuroblastoma cells use either insulin-like growth factor-I or insulin-like growth factor-II in an autocrine pathway via the IGF-I receptor: variability of IGF, IGF binding protein (IGFBP) and IGF receptor gene expression and IGF and IGFBP secretion in human neuroblastoma cells in relation to cellular proliferation. 940 29

It was reported recently by our group that the transfection of GD3 synthase cDNA into Neuro2a cells, a neuroblastoma cell line, caused cell differentiation with neurite sprouting (Kojima et al., 1994; J. Biol. Chem., 269, 30451-30456). To further explore this phenomenon in detail, we applied tetracycline-regulated system to control the expression of GD3 synthase cDNA in Neuro2a cells. Under this system, the process of Neuro2a cell differentiation was rather slow, about 3 weeks of cell culturing in the absence of tetracycline was required for most cells to extend the neurite-like structures. The RNase protection assay indicated that the mRNA of GD3 synthase gene was first detected between 4 h and 8 h after the gene was activated and kept at approximately the same level through the process. Furthermore, time-course analysis of total ganglioside expressions has shown that GD3 and GT1b gangliosides appeared on the cell surface early in the process and reached the maximum level around day 6. We also found that the amounts of GD3 and GT1b on the cell surface started to decrease after day 6 and returned gradually to the basal values after 3 weeks. On the other hand, GQ1b and GD1b were started to be synthesized at early stage and the amounts were continuously to increase through the whole Neuro2a morphological change process. In addition, time-course analysis by flow cytometry method for GD3 and GQ1b suggested that the conversions of simple gangliosides to more complex gangliosides may be required to induce the Neuro2a differentiation. Our results indicated that the combination of cDNA transfection and regulated gene expression is a powerful tool to study the function of glycolipids and should have a general application to the glycobiology field.
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PMID:Regulated expression system for GD3 synthase cDNA and induction of differentiation in Neuro2a cells. 945 7

Neuroblastoma, a childhood tumour of the sympathetic nervous system, may sometimes regress spontaneously in infants, or progress to a poor clinical outcome despite intensive therapy. Neuroblastomas express neurotrophin receptors and high levels of mRNA for trk-A correlates with favourable outcome, whereas trk-B mRNA is expressed by more unfavourable tumours. Using a sensitive RNase protection assay, mRNA expression for the neurotrophin receptor trk-C was investigated in 50 tumour samples from 45 children at different stages including metastatic and relapsing tumour tissue, out of which 22 were also investigated for trk-A mRNA. Thirty-seven of 43 primary tumours (86%) showed trk-C mRNA with more than 300-fold difference between the highest and the lowest values. A higher trk-C index (trk-C mRNA/GAPDH mRNA) was associated with favourable features such as younger age (P = 0.009-0.003), favourable tumour stage (1, 2 or 4S; P < 0.001) and favourable prognosis (P = 0.044). Better survival probability was shown in children with intermediate or high trk-C index compared with patients with low or undetectable levels (P = 0.031). All localised tumours co-expressed mRNA for trk-A and trk-C receptors. RT-PCR analysis detected mRNA encoding the cytoplasmic trk-C tyrosine kinase region only in favourable neuroblastomas. We conclude that favourable neuroblastoma may express the full-length trk-C receptor while unfavourable tumours, especially those with MYCN amplification, seem to either express no trk-C or truncated trk-C receptors with unknown biological function. Trk-C and possibly its preferred ligand NT-3 may be involved in the biology of favourable neuroblastomas showing apoptosis or differentiation.
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PMID:Coexpression of mRNA for the full-length neurotrophin receptor trk-C and trk-A in favourable neuroblastoma. 958 79

Hel-N1 and HuD belong to the elav gene family and encode neuron-specific RNA-binding proteins that are temporally regulated in neural development. Recently, these genes have been detected in small cell lung carcinoma, a neuroendocrine tumor, with HuD down-regulated in poorly differentiated, variant subsets. We, therefore, sought to determine: (a) the extent to which Hel-N1 and HuD are expressed in neuroblastoma (NB); and (b) whether the individual patterns of expression are associated with clinical features of the tumor. We used a sensitive and quantitative RNase protection assay that reliably distinguishes between these homologous genes, and with it we show that Hel-N1 and HuD transcripts were detected in 100% of cultured cells (11 of 11) and 97% of primary tumor samples (35 of 36). Densitometric quantification of transcripts indicated that the levels of HuD and Hel-N1 varied in all samples. In primary NB tissue, samples that expressed the highest Hel-N1 or HuD levels were N-myc unamplified. With HuD, the level in unamplified primary tumors was significantly higher than that of amplified tumors (0.80 +/- 0.12 versus 0.33 +/- 0.12, P < 0.02). HuD expression in prognostically favorable tumor stages was also significantly higher than unfavorable stages (0.98 +/- 0.19 versus 0.47 +/- 0.08, P < 0.03). In summary, the ubiquitous detection of HuD and Hel-N1 in NB indicates that they are molecular neuronal markers of this tumor. Furthermore, high HuD mRNA levels may predict a clinically favorable outcome.
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PMID:Neuron-specific hel-N1 and HuD as novel molecular markers of neuroblastoma: a correlation of HuD messenger RNA levels with favorable prognostic features. 981 74

DCC, a candidate tumor suppressor gene from chromosome 18q21, is most highly expressed in the developing nervous system. In vitro studies suggest a role for DCC in neuronal differentiation, and 18q allelic loss occurs in a subset of neuroblastomas. To address the hypothesis that loss of DCC function may contribute to tumorigenesis in cells of neural origin, we utilized a combination of RNase protection, immunoblotting, and immunohistochemical approaches to characterize DCC expression in 62 primary neuroblastomas and 16 neuroblastoma cell lines. The DCC protein was undetectable in 38% of the primary tumors and 56% of the cell lines. Of note, primary tumors lacking DCC expression were more likely to have been obtained from patients with disseminated or stage D disease (P = 0.01). In addition, loss of DCC expression was observed in three of six primary tumors from stage DS patients. No consistent relationship between the loss of DCC expression and N-myc amplification was observed in our studies. Our findings suggest that loss of DCC expression may contribute to the dissemination of neuroblastoma cells, perhaps through alterations in growth and differentiation pathways distinct from those regulated by N-myc.
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PMID:Loss of DCC expression in neuroblastoma is associated with disease dissemination. 981 73

Bovine seminal ribonuclease (BS-RNase) is a homologue of RNase A with specific antitumor activity. The cytotoxic action of this agent was examined in human neuroblastoma (NB) cell lines (SK-N-SH and UKF-NB-4) possessing the multidrug resistance (MDR) phenotype and NB cell lines (IMR-32, UKF-NB-1, UKF-NB-2 and UKF-NB-3) without MDR. Although MDR cells expressed large amounts of mdr-1 mRNA, contained functional P-glycoprotein and had 20- to 105-fold lower sensitivities to doxorubicin and vincristine than cells with non-MDR phenotypes, BS-RNase was equally toxic to all NB cells at concentrations employed (0.2 to 100 microg/ml). BS-RNase showed high selectivity for NB cells and was non-toxic to normal fibroblasts and epithelial cells. Ultrastructural investigation and annexin V assay showed that BS-RNase is a powerful inductor of apoptosis. The antitumoral effects of BS-RNase were also demonstrated in vivo using established subcutaneous xenografts in athymic (nude) mice of the MDR-1-bearing UKF-NB-4 cell line. Intratumoral injections (12.5 mg/kg) of BS-RNase over four weeks resulted in complete tumor regression and absence of tumor regrowth over a two-week observation period after cessation of treatment. The results show that BS-RNase selectively kills NB cells by inducing apoptosis and that this agent is active against mdr-1 expressing cells both in vitro and in vivo. BS-RNase fulfills important criteria for a candidate antitumor agent in NB patients with advanced disease.
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PMID:Bovine seminal ribonuclease selectively kills human multidrug-resistant neuroblastoma cells via induction of apoptosis. 1053 85


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