BioProject

The discovery of either missense mutations or amplification of ALK (Anaplastic Lymphoma Kinase) gene identified this receptor tyrosine kinase as a therapeutic target in neuroblastoma (NB). Moreover, a high ALK expression has been associated with cases of metastatic NB and with a worse prognosis. In order to identify miRNAs involved in the regulation of ALK expression in NB we therefore analyzed their expression profile in 16 NB cell lines and in 22 patients by qPCR. We then identified miRNAs which were differentially expressed between two groups of samples showing high (ALK+) or low (ALK-) expression levels of ALK by using microarrays containing 866 human miRNA probes (Agilent). Next, the differential expression analysis between the two groups (ALK+ and ALK-) was performed using R. Our analysis showed a higher expression of 30 and 23 miRNAs (p-value <0.05) in NB lines and samples, respectively, both belonging to the ALK- group. Validation analysis and filtering according to in silico suggested miR-424-5p as a potential ALK regulator candidate. Dual luciferase assay indicated a direct binding of this miRNA to ALK-3’UTR. Moreover, we observed a down-regulation of ALK protein expression following transfection of miR-424-5p mimic as well as inhibition of cell viability in ALK+ NB cell lines. In conclusion, our data suggest miR-424-5p as involved in the regulation of ALK expression in NB. Overall design: A total of 22 NB samples (divided in ALK+ and ALK- according to gene expression analysis) were studied to obtain microRNA profile. After quality control 2 samples were excluded from further analysis