Abstract 4400: MicroRNA loaded circular dumbbell RNAs, a novel antiangiogenic approach

Abstract

Abstract Angiogenesis is a tightly regulated biological process where new blood vessels are formed from pre-existing blood vessels. This process is also critical in diseases such as cancer; therefore, angiogenesis has been actively explored as a drug target for cancer therapy. Many patients treated with endogenous angiogenesis inhibitors show increased survival; however, eventual resistance to therapies is associated with disease progression and death. The future of effective anti-angiogenic therapy lies in the intelligent combination of multiple targeting agents with novel modes of delivery to maximize therapeutic effects. We therefore propose a novel and ‘out of the box' approach that utilizes dumbbell-RNA (dbRNA) to target pathological angiogenesis by simultaneously targeting multiple molecules and processes that contribute to angiogenesis. Dumbbell RNAs are a stable and safe alternative to viral, non-viral, and naked plasmid-based gene-transfer systems. They integrate the advantages of durable expression that is achievable with integrating viral vectors and short-term effects triggered by naked RNA. In this study, we have successfully constructed a plasmid expressing miR-34a dbRNA using the permuted intron-exon (PIE) method. We have also modified and optimized a cost effective protocol to purifiy dbRNA from bacterial culture with high purity. To test the efficacy of miR-34a dbRNA, we used the pancreatic cancer cell line MIA-PaCa2. When transfected into MIA-PaCa2 cell line we observed increased expression of miR-34a. Further, miR-34a overexpression caused a 3- fold and 2.5-fold decrease in VEGFA and VEGFB RNA expression respectively. Functional validation on the effect of miR-34a on angiogenesis was performed on Human umbilical vein endothelial cells (HUVEC) using the tube formation assay, where miR-34a dbRNA showed significant decrease in tube formation when compared to cells treated with scrambled dbRNA. We will further validate these results in vivo using Zebrafish angiogenesis model. In conclusion, our study demonstrate for the first time a novel approach to block angiogenesis using miR-34a loaded dbRNA. Our data also show that this approach may be used in targeting multiple molecules/pathways, and when used in combination with existing therapies can improve the efficacy of current treatment modalities. Citation Format: Manu Gnanamony, Sajani S. lakka, Jaime Libes, Julian Lin, Pushpa A. Joseph, Christopher S. Gondi. MicroRNA loaded circular dumbbell RNAs, a novel antiangiogenic approach [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4400.