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Query: UMLS:C0027819 (neuroblastoma)
 27,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The expression of the protooncogene c-src has been studied in specimens of childhood tumors with special reference to neuroblastoma and other tumors of neuronal origin. For comparison c-src gene expression was studied in seven neuroblastoma and neuroepithelioma cell lines. The structurally distinct neuronal product of the gene, pp60c-srN, expressed during normal development in neuroblasts and neurons, was identified by immunoblotting technique together with the fibroblast form, pp60c-src. While pp60c-src was found in most tumors studied, the neuronal form was restricted to neuroblastomas (23 of 27) and retinoblastomas (3 of 3) and could not be detected in the other childhood tumors. A dominance of the neuronal form, pp60c-srcN, was exclusively found in the infant cases of neuroblastoma (9 of 12), estimated to have good prognosis. These results indicate that pp60c-srcN might be a diagnostic marker in primitive childhood tumors. When expressed in higher amounts than pp60c-src, pp60c-srcN may be a positive prognostic marker in neuroblastoma, especially useful in the evaluation of infants. In addition, lack of pp60c-srcN seems to be incompatible with low stage neuroblastoma.
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PMID:Expression of the neuronal form of pp60c-src in neuroblastoma in relation to clinical stage and prognosis. 169 45

The authors have investigated the relationship between oncogene (N-myc and c-src) expression and major histocompatibility complex (H-2 in the mouse) antigen gene expression at the molecular levels, by using mouse neuroblastoma sublines (NB-1 and NB-V). Fluorescence-activated cell sorter analysis showed that NB-1 cells exhibited positive expression to H-2 Kk, H-2 Dd, and beta-2-microglobulin, while NB-V cells were negative to all three antigens. It was found that dimethyl sulfoxide (DMSO) had a capacity to increase an H-2 class I antigen expression on NB-1 cells, whereas no change was observed on NB-V cells after DMSO treatment. Molecular analysis with deoxyribonucleic and ribonucleic acid (RNA) blot hybridization and immunoprecipitation revealed that the enhancement of H-2 antigen expression on NB-1 cells was modulated at the transcriptional control of the H-2 gene. In contrast, negative H-2 antigen expression on NB-V cells was caused by block at the level of glycosylation of the H-2 heavy chain, although an increase in messenger RNA of the H-2 gene was induced after DMSO treatment. There was neither amplification nor rearrangement of N-myc and c-src oncogenes in either neuroblastoma subline. Nuclear run-on transcription assay revealed that the N-myc gene was post-transcriptionally down-modulated by DMSO, whereas the c-src gene was transcriptionally up-regulated. It was thus suspected that N-myc and c-src might be directly associated with cellular proliferation and differentiation in neuronal tumors and that in vivo tumorigenicity could be regulated by the control mechanism of oncogene expression in relation to H-2 gene expression on tumor cells.
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PMID:[Molecular analysis of relationship between oncogene (N-myc and c-src) expression and major histocompatibility complex antigen gene expression in mouse neuroblastoma lines]. 170 53

The neuron-specific splicing of the mouse c-src N1 exon was analyzed. Model src genes, transiently expressed in HeLa and LA-N-5 neuroblastoma cells, were assayed for the insertion of the 18-nucleotide neuron-specific N1 exon into their product mRNA. The normal clone fails to use this exon in HeLa cells but inserts the exon into 50% of the mature mRNA in LA-N-5 cells. When the exon and flanking intron sequences are placed between two adenovirus exons, the N1 exon is still only inserted in the neural cells. Thus, the neural specificity is a property of the exon itself and its immediate flanking sequences. Simply extending the length of the N1 exon to 109 nucleotides allows its efficient use in HeLa cells, implying that the exon is normally skipped because it is too short to allow spliceosomes to assemble at both ends simultaneously. This model predicts that exclusion of the exon should be sensitive to proteins or mutations that alter the relative strength of the flanking splice sites. Mutations that change these splice sites support this hypothesis.
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PMID:Does steric interference between splice sites block the splicing of a short c-src neuron-specific exon in non-neuronal cells? 200 41

Genomic amplification of the N-myc protooncogene in neuroblastomas correctly predicts poor outcome for the patients. However, the prognosis for neuroblastomas with a single copy of N-myc is also poor in cases diagnosed after 1 year of age but good in infantile cases. To elucidate the different prognoses depending upon the age of the patients with neuroblastoma, we performed an analysis of the expression of protooncogenes related to neural differentiation. We examined the genomic amplification of N-myc in 26 specimens of neuroblastomas and further analyzed 22 of the 26 cases for expression of N-myc, c-src, c-Ha-ras, and c-fos. Consequently, we observed frequent overexpression of N-myc in undifferentiated neuroblastomas and enhanced expression of c-src and c-Ha-ras in infantile neuroblastomas with favorable prognosis and in neuroblastomas differentiated by chemotherapy. These findings suggest that c-src and c-Ha-ras play important roles in the neural differentiation of infantile neuroblastomas.
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PMID:Expression of N-myc and c-src protooncogenes correlating to the undifferentiated phenotype and prognosis of primary neuroblastomas. 203 93

The proto-oncogene c-src codes for two tyrosine kinases, pp60c-src and pp60c-srcN. The latter protein appears to be exclusively expressed in neurons and neuronally differentiated tumors. In cell lines derived from neuroblastoma and small-cell lung carcinoma, src expression correlates positively with neuroendocrine differentiation. However, pp60c-srcN is expressed only in highly differentiated neuroblastomas. Although c-src expression in neuroendocrine tumors probably reflects and is the result of the differentiation stage at which the tumors have been arrested, high c-src expression and kinase activities in non-neuroectodermal tumors, e.g., colon carcinoma, breast carcinoma, might instead be a part of the malignant phenotype and contribute to the development of these tumors.
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PMID:src expression in small-cell lung carcinoma and other neuroendocrine malignancies. 217 63

We have observed a 20- to 40-fold increase in pp60c-src tyrosyl kinase activity in human neuroblastoma cell lines over that found in either human glioblastoma cells or human fibroblasts. The level of c-src gene transcripts and pp60c-src protein synthesis in the neuroblastoma cells was not significantly increased when compared to the levels found in glioblastoma cells. Approximately one-half of the pp60c-src molecules synthesized during a 4-hr [35S]methionine or [32P]orthophosphate labeling period in neuroblastoma cells were found to migrate more slowly on NaDodSO4/polyacrylamide gels than pp60c-src molecules labeled in glioblastoma cells. Peptide and phosphoamino acid analysis of the in vivo phosphorylated c-src molecules from these two cell types revealed that pp60c-src molecules from the neuroblastoma cells possess in the amino-terminal portion of the protein at least one unique tyrosine phosphorylation site not found in pp60c-src derived from glioblastoma cells.
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PMID:Increased pp60c-src tyrosyl kinase activity in human neuroblastomas is associated with amino-terminal tyrosine phosphorylation of the src gene product. 241 74

We examined the expression, abundance, and protein kinase activity of pp60c-src in two different pairs of genetically indistinguishable cloned human neuroblastoma cell variants which display altered phenotypes as the result of conversion from a neuronal to a non-neuronal phenotype. The results demonstrate that cells which exhibit the neuroblastic (N-type) phenotype possess high levels of pp60c-src protein and that one of the two N-type cell lines is capable of expressing the neuronal-specific isoenzyme of pp60c-src. In contrast, cells which display the substrate-adherent (S-type) phenotype have low levels of pp60c-src protein and express exclusively the non-neuronal isoenzyme of pp60c-src. In all cells examined the abundance of pp60c-src was found to be proportional to the steady-state level of c-src RNA. In each case the protein kinase activity of pp60c-src was found to be proportional to the abundance of the protein and independent of the ratio of neuronal to non-neuronal species of pp60c-src.
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PMID:Coordinate alteration of pp60c-src abundance and c-src RNA expression in human neuroblastoma variants. 247 6

Four human neuroblastoma cell lines exhibited differences in their ability to differentiate into neuron-like cells in response to three different treatments, serum deprivation, or additions of dibutyryl cyclic-AMP or retinoic acid. Expression of N-myc gene product was reduced in neuroblastoma cell line SK-N-DZ differentiated by retinoic acid as compared with untreated cells. On the contrary, expression of c-src gene product, pp60c-src, was considerably enhanced in differentiated SK-N-DZ cells. Tyrosine phosphorylation of several cellular proteins was found to be enhanced in differentiated cells. Alteration in expression of these proto-oncogene products might be important in the differentiation of neuroblastoma cells into neuron-like cells.
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PMID:Expression of proto-oncogene products during drug-induced differentiation of a neuroblastoma cell line SK-N-DZ. 248 Jun 94

Human cell lines with neuronal and neuroendocrine features were examined for their expression of pp60c-src, the cellular homolog of the transforming gene product pp60v-src of Rous sarcoma virus. Four neuroblastoma (LA-N-5, SH-SY5Y, Paju, and SK-N-MC) and three small-cell lung carcinoma (U-2020, U-1690, and U-1285) cell lines were selected on the basis of their stage of neurocrine differentiation, as determined by the expression of neuron-specific enolase. In an immune complex protein kinase assay, all seven cell lines displayed c-src kinase activity which was considerably higher than that found in nonneurocrine cells (human diploid fibroblasts, glioma, and non-small cell lung carcinoma cell lines). Furthermore, the c-src kinase activity, as determined by autophosphorylation or phosphorylation of an exogenous substrate, enolase, correlated with the stage of neurocrine differentiation. There was an approximately 30-fold difference in c-src kinase autophosphorylation activity between the cell lines representing the highest and lowest stages of neurocrine differentiation. A similar variation was found in the steady-state levels of the c-src protein of these cell lines. Highly differentiated neuroblastoma cells expressed two forms of the src protein. Digestion by Staphylococcus aureus V8 protease did reveal structural diversity in the amino-terminal ends of these c-src molecules. In summary, we found a clear correlation between c-src kinase activity and the stage of neuronal and neuroendocrine differentiation. Thus, the phenotypic similarity between neurons and neuroendocrine cells includes high c-src expression.
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PMID:Expression of c-src in cultured human neuroblastoma and small-cell lung carcinoma cell lines correlates with neurocrine differentiation. 283 Apr 84

Neuroblastoma (NB) cells can be induced to differentiate bidirectionally into either neuronal or schwannian cells by different inducers. However, the underlying mechanisms are poorly understood. We examined the expression of N-myc and c-src genes in 3 human NB-cell lines during either neuronal or schwannian differentiation in vitro, since proto-oncogenes are considered to play a pivotal role in regulating cell proliferation and differentiation. Decreased N-myc expression and increased c-src expression were observed during neuronal differentiation by retinoic acid, polyprenoic acid (E5166) and dibutyryl cyclic AMP, whereas the expression of N-myc and c-src genes was considerably reduced during schwannian differentiation by bromodeoxyuridine, demonstrating that the expression of N-myc and c-src genes was regulated independently in the bipolar differentiation processes of NB cells. Our results suggest that enhanced N-myc expression might be closely linked to the undifferentiated phenotypes of NB cells, that c-src expression might be related to the neuronal differentiation of NB cells, and that N-myc and c-src genes might be regulated independently in the determination of the bipolar differentiation of NB cells.
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PMID:Differential expression of N-myc and c-src proto-oncogenes during neuronal and schwannian differentiation of human neuroblastoma cells. 291 4


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