PO-353 Functional high-throughput screening reveals multiple tumour-suppressive microRNAs in neuroblastoma

Introduction Despite multimodal therapies, a significant percentage of high-risk neuroblastomas remain incurable. One of the major causes of treatment failure is the development of multi-drug resistance through multiple mechanisms. Therefore, targeting single elements of a pathway may not suffice. In this respect, it is desirable to find molecules, such as microRNAs (miRNAs), which can regulate multiple cellular processes, thereby minimising the risk of resistance and improving the clinical response. Material and methods To identify tumour-suppressive miRNAs in neuroblastoma, we performed a high-throughput functional screening using 2048 individual miRNAs. Cell proliferation and viability were analysed by crystal violet staining, FACS and western-blot. MiRNA-target prediction analysis was performed in silico and further validated by quantitative real-time PCR, western blot and luciferase-reporter assays. The therapeutic potential of miRNA-restoration therapies in vivo was validated using xenograft models. Statistical significance was determined by two-tailed unpaired Student’s t-test. Results and discussions Several miRNA whose overexpression reduced cell proliferation and viability in multiple chemoresistant NB cell lines in vitro and in vivo were identified. Those with the highest therapeutic potential were found to target several genes related to cancer, cell cycle and cell survival. Conclusion MicroRNA-based restoration therapies could be a therapeutic alternative against neuroblastomas resistant to conventional therapies.