Preliminary analysis of stem cell-like cells in human neuroblastoma.

BACKGROUND Neuroblastoma is an embryonic neoplasm originating from the neural crest with cellular heterogeneity as one of its oncobiological characteristics. This study was undertaken to determine whether human neuroblastoma contains stem cell-like cells. METHODS Twenty patients with neuroblastoma who have been treated in our hospital since January 2005 were divided into pre-operative chemotherapy (10 patients) and non-chemotherapy (10) groups. Tumor specimens of the patients were taken and paraffin sections were made. The expressions of stem cell markers CD133, ABCG2, CD117 and nestin were immunohistochemically detected in the specimens. Neuroblastoma cells were stained with Hoechst 33342 and PI. The side population (SP) cells were analyzed by the fluorescence-activated cell sorter. The disparity drug resistance to cisplatin (DDP) of SP and non-SP cells was measured with MTT colorimetric assay. The oncogenicity of SP and non-SP cells was identified in nude mice. RESULTS There was no significant difference in the expression intensity of CD117 and nestin between the two groups of specimens (P>0.05). There was a significant difference between the two groups in terms of the expression intensity of CD133 and ABCG2 (P<0.05). The SP cells accounted for 0.2%-1.3% of the total human neuroblastoma cells and were decreased to 0.1%-0.5% after verapamil treatment. The SP and non-SP cells showed disparity in cell growth experiment and drug resistance to DDP. Oncogenicity experiment revealed that nude mice could erupt tumor by an injection of l×10(6) SHSY5Y and WIV SP cells. However, the nude mice could not form tumor by an injection of l×10(6) non-SP cells. CONCLUSION Neuroblastoma might contain cancer stem cell-like cells.