Anti-seed PNAs targeting multiple oncomiRs for brain tumor therapy

Abstract

ABSTRACTGlioblastoma (GBM) is one of the most lethal malignancies in the United States with poor survival and high recurrence rates, suggesting the need for approaches targeting the most important molecular drivers of tumor growth. Here, we aimed to simultaneously target oncomiRs 10b and 21, which have been reported to drive the aggressive growth and invasiveness of GBM. We designed short (8-mer bases) gamma-(γ)-modified peptide nucleic acids (sγPNAs), which target the seed region of oncomiRs 10b and 21 with high affinity. We entrapped these anti-miR sγPNAs in nanoparticles (NPs) formed from a block copolymer of poly(lactic acid) and hyperbranched polyglycerol (PLA-HPG); the NPs were also functionalized with aldehydes to produce bioadhesive NPs. We have previously shown that these bioadhesive NPs (BNPs) produce superior transfection efficiency, with a tropism for tumor cells. The sγPNA BNPs showed superior anti-miR efficacy in comparison to the regular full length PNA BNPs in vitro. When combined with temozolomide, sγPNA BNPs administered via convention-enhanced delivery (CED) inhibited the growth of intracranial tumors and significantly improved the survival of animals (>120 days). RNA sequencing analysis revealed the role of vascular endothelial growth factor A (VEGFA) and integrin beta 8 (ITGB8), direct targets of both miR-10b and miR-21, in mediating the tumor growth. Hence, we established that BNPs loaded with anti-seed sγPNAs targeting multiple oncomiRs is a promising approach to improve the treatment of GBM, with a potential to personalize treatment based on tumor specific oncomiRs.SummaryTargeting oncomiRs 21 and 10b to improve GBM survivalGlioblastoma (GBM) is an aggressive malignant disorder with high recurrence rates and poor survival. Here, we aimed to simultaneously inhibit two aberrant oncomiRs—miR 21 and miR 10b—which have been previously associated with GBM invasiveness and progression. We synthesized short, gamma-modified peptide nucleic acids (sγPNA) targeted to the miR seed regions and loaded the sγPNAs into bioadhesive nanoparticles (BNPs). When the sγPNA-BNPs were added to cultured tumor cells, we observed significant reduction of target oncomiRs and increase of apoptosis in vitro. When delivered in vivo by convection-enhanced delivery, sγPNA BNPs dramatically increased the survival in two orthotopic (intracranial) mouse models of GBM. Moreover, the combination of sγPNA BNPs with temozolomide (TMZ) increased the survival of mice with GBM beyond the planned endpoint (120 days) with significant improvements in histopathology. The proposed strategy of sγPNA BNP with TMZ provides an alternative, promising approach for treatment of GBM.