Detection of lower levels of SNAP25 using multiple microarray systems and its functional significance in medulloblastoma

Medulloblastoma (MB) is the most common pediatric malignant brain tumor and patients with a high-risk or recurrent MB respond poorly to current therapies, with higher related mortality. Potential molecules related to MB must be identified to develop targets for therapeutic development. In the present study, we compared MB microarray data obtained using different microarray systems and significant targets were selected by gene annotation and enrichment analysis. Genes for soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) annotated with the function “vesicle” were identified and one of these proteins, synaptosomal-associated protein 25 (SNAP25), had significantly lower expression levels in MB. In addition, SNAP25 was detected in a very low number of MB cells according to western blot analysis and immunohistochemical analyses of archived and formalin-fixed/paraffin-embedded human MB specimens. We found that SNAP25 could change the morphology and the chemotherapeutic effect of arabinofuranosyl cytidine (Ara-C) on SNAP25-expressing MB cells. In conclusion, the expression of SNAP25 is crucial for the dendrite formation and correlate to the targeted chemotherapy. The detection of SNAP25 expression in MB cells may be essential for the chemotherapeutic application of Ara-C. In the present study, various MB microarray data were extracted and compared. Significant genes that had similar expression patterns in MB according to different microarray systems were selected following gene annotation. Enrichment analysis of the gene set was also performed to elucidate the biological pathways and processes that are affected in patients with MB. Archived and formalin-fixed/paraffin-embedded human MB specimens were also used to validate the significant candidates. A crucial molecular pathway related to MB was identified by this whole-genome survey.