The expression of the NCAM gene was analysed at both the protein and messenger levels in material extracted from Ewing cell lines, human neuroblastoma cell line and fetal mouse brain.
Several antibodies to melanoma and neuroblastoma associated antigens including two monoclonal antibodies to the nerve growth factor receptor were also found to react with Ewing cells.
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.
Moreover, extra-copies of cellular oncogenes have been located in tumor cells in vivo; particularly N-myc gene amplification was discovered in advanced stage of neuroblastoma (NB).
Hybrids formed between Thy-1+ human neuroblastoma cells and Thy-1- mouse neuroblastoma cells, or hybrids between Thy-1+ human fibroblasts and the Thy-1- mouse kidney carcinoma, RAG, retain human Thy-1 expression.
It is concluded that in situ hybridization of tissue sections is as effective as Southern blot analysis of tumor cell DNA in identifying human neuroblastoma tumors in which the N-myc gene is of prognostic significance.
These results suggest that p53 levels are intimately related to an undifferentiated phenotype in neuroblastoma cells and support studies which relate p53 levels to the malignant phenotype in other tumor systems.
Gene amplification and rearrangements are discussed through review of recent work on the N-myc gene in neuroblastoma and the epidermal growth factor receptor (EGFR) gene in glioblastoma.
To assess the biological consequences of superoxide dismutase 1 overproduction within cells, the human superoxide dismutase 1 gene and a human superoxide dismutase 1 cDNA were introduced into mouse L cells and NS20Y neuroblastoma cells.
According to this criterion, 14 cases (12 cases of neuroblastoma and 2 cases of ganglioneuroblastoma) were positive for N-myc gene amplification of 27 cases (18 cases of neuroblastoma, 5 cases of ganglioneuroblastoma, and 4 cases of composite ganglioneuroblastoma).
Gene amplification and rearrangements are discussed through review of recent work on the N-myc gene in neuroblastoma and the epidermal growth factor receptor (EGFR) gene in glioblastoma.
SH-EP cells, a clone derived from the same neuroblastoma cell line as SH-SY5Y but which displays melanocyte rather than neuronal lineage markers, also express significantly more EGF receptor than SH-SY5Y cells.
Gene expression was confirmed by the presence of proenkephalin mRNA and proenkephalin-derived polypeptides in extracts of the SK-N-MC cells and also in the neuroblastoma SH-SY5Y cell line.
In these studies, we have found that the expression of no fewer than five proto-oncogenes including c-Ha-ras, c-ets-1, and c-fos change during the differentiation of NB cells, while the expression of c-erb-B changes in association with the arrest of growth that occurs during NB differentiation.