Polymeric nanoparticle mediated inhibition of miR-21 with enhanced miR-124 expression for combinatorial glioblastoma therapy

Glioblastoma (GBM) is the most common and fatal form of malignant brain tumor. Despite intensive effort, there is still no effective GBM treatment. Therefore, novel and more effective GBM therapeutic approaches are highly desired. In this study, we combined polymeric nanotechnology with microRNA (miRNA) regulation technology to develop a targeted polymeric nanoparticle to co-deliver anti-miR-21 and miR-124 into the brain to effectively treat GBM. The polymeric nanoparticle decorated with Angiopep-2 peptide not only can encapsulate miRNA via triple-interaction (electrostatic, hydrogen bond and hydrophobic bonding) to protect miRNA against enzyme degradation in the blood, but also is capable of crossing blood brain barrier (BBB) and allowing targeted delivery of miRNAs to GBM tissue due to the dual-targeting function of Angiopep-2. Moreover, the co-delivered anti-miR-21 and miR-124 simultaneously regulated the mutant RAS/PI3K/PTEN/AKT signaling pathway in tumor cells, consequently achieving combinatorial GBM therapy. This combinatorial effect was confirmed by our results showing that these miRNA nanomedicines can effectively reduce tumor cell proliferation, migration and invasion as well as reducing tumor angiogenesis. Consequently, effective suppression of tumor growth and significantly improved medium survival time are observed when these miRNA nanomedicines were assessed in an orthotopic GBM xenograft model. This work indicated that our new polymeric nanoparticles successfully mediate inhibition of miR-21 and miR-124 supplementation to significantly reduce tumorigenesis, and may have strong potential in GBM therapy.