Neuroblastoma cell, analysis

Besides the synthetic inhibitors, a variety of natural compounds is known to inhibit the CP. One of these natural inhibitors, lactacystin, was discovered by its ability to induce neurite outgrowth in a murine neuroblastoma cell line. Incubation of cells in the presence of radioactive lactacystin leads to the labelling of the yS5 subunit (Fenteany et al. 1995) and to irreversible inhibition of the CP. As shown by X-ray analysis, the inhibitor is covalently attached to subunit fS5 by an ester bond with the N-terminal ThrlO (Groll et al. 1997) (see Figure 10.7A). The subunit selectivity of lactacystin can be attributed to its dimethyl group, which mimics a valine or a leucine side chain and closely interacts with Met45 in the hydrophobic SI pocket of subunit j85. 

Klebe, R. J., and Ruddle. F. H. (1969). Neuroblastoma Cell culture analysis of a differentiating stem cell system. J. Cell Biol. 43, 69A. 

FIGURE 2.2 Methylation-specific PCR (MSP) analysis of the MDR-1 gene promoter methylation in human neuroblastoma (NB) cell lines (procured from Children s Oncology Group [COG] Philadelphia, PA) established from patients after chemotherapy.Methylation status of MDR-1 gene is represented as unmethylated (U) and methylated (M) in each cell type. A total of 19 neuroblastoma cell lines ° were examined by MSP and data indicate hypomethylation of MDR-1 gene in all cell lines tested. Hypomethylation (U) of MDR-1 gene indicates its increased expression and development of resistant phenotype in neuroblastoma cells after intensive chemotherapy. 

Events that initiate misfolding of the native PrP polypeptide remain mostly unknown however, it has been shown in a model system of neuroblastoma cell cultures that normal PrP is precursor to PrP (Borchelt et al., 1990). These studies employed a 2-h pulse of [ S]-methionine to label the newly synthesized PrP. Kinetic analysis of [ S]-radioactivity in purified protein showed that labeling peaked immediately in the PrP pool and rapidly declined to less than 90% of peak activity within 14-22 h, whereas radioactivity was still increasing after 46 h in the 1 - = pool. Given a pulse duration of only 2 h, followed by chase, it is reasonable to assume labeled PrF is the direct precursor of labeled PrP Furthermore, studies with recombinant PrP polypeptides show that a-helix-rich polypeptides, which are characteristic of the native PrP configuration, can be... 

Lee, C, Fisher, SK, Agranoff, BW and Hajra, AK (1991) Quantitative analysis of molecular species of diacylglycerol and phosphatidate formed upon muscarinic receptor activation of human SK-N-SH neuroblastoma cells. Journal of Biological Chemistry, 266, 22837-22846. 

Coco S, Defferrari R, Scaruffi P et al. Genome analysis and gene expression profiling of neuroblastoma and ganglioneuroblastoma reveal differences between neuroblastic and Schwannian stromal cells. J Pathol 2005 207-346-357. 

The analysis of ganglioneuroblastomas and neuroblastomas indicates that the level of N-wyc expression is highest in the most undifferentiated cells, which show atypical aggressive biological behavior. 

Combaret V, Gross N, Lasset C, et al. Clinical relevance of CD44 cell-surface expression and N-myc gene amplification in a multicentric analysis of 121 pediatric neuroblastomas. J Clin Oncol. 1996 14 25-34. 

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