Gene expression of growth signaling pathways is up-regulated in CD133-positive medulloblastoma cells.

Medulloblastoma (MB) is the most common malignant brain tumor in children. Cancer initiating cells (CICs) have been proposed to be involved in the development of brain tumors including MB. Prominin-1 antigen (CD133) is a candidate surface molecular marker for CICs. In the present study, CD133-positive cells were isolated from human Daoy MB cells and their gene expression was compared with that of control Daoy cells. DNA microarray analysis revealed that there were 398 up-regulated genes (>2-fold increase) and 318 down-regulated genes (<50% decrease) in the CD133-positive cell-enriched fractions. Up-regulated genes included neuregulin-1, cyclin D1, cyclin-dependent kinase 6, vascular endothelial growth factor, inhibin β A, promyelocytic leukemia gene, MYC, and hairy enhancer of split-1, which are components of growth signaling pathways. Molecular studies suggest that developmentally regulated signals important for stem cell maintenance are also involved in MB tumorigenesis. Moreover, these molecules can serve as novel targets for MB treatment.