Abstract 3906: A novel cationic liquid crystalline nanoparticle for the delivery of synthetic RNAi-based therapeutics

Abstract

Abstract Small interference RNA (RNAi)-based therapeutics have been used to silence expression of targeted pathological genes. However, short half-life, poor cellular uptake, and non-specific distribution of small RNAs call for the development of novel delivery systems to facilitate the use of RNAi as a new class of therapeutics. We developed a novel cationic liquid crystalline nanoparticle (CLCN) with microfluidic-facilitated encapsulation of hydrophilic biomolecules for efficiently delivering synthetic RNAi-based therapeutics including siRNAs, PNAs, and micro-RNA mimics. CLCNs were prepared by mixing under high speed homogenization a lipophilic phase with a hydrophilic phase containing an emulsifier/stabilizer such as poloxamer. CLCNs were assembled with synthetic small siRNA molecules in nuclease free water to create CLCN/siRNA complexes. The homogenous and stable CLCNs and CLCN-siRNA complexes dispersed in nuclease free water displayed sizes under 100 nm and positive charges between 25-35 mV on the CLCN surface as demonstrated by the NanoTracking and Zeta potential measurements. The gel retardation assay indicated that the binding between the carrier and the siRNA was strong enough to withstand dissociation during electrophoresis. No cytotoxicity was detected in both lung cancer and normal cells treated with various concentrations of CLCNs (from 0.01 to 100 μM) by in vitro cell proliferation assay. The CLCNs were taken up by human cells though endocytosis after binding with the cell membrane and traveling from early endosomes to the lysosome after 24 h treatment as shown by intracellular trafficking analysis with transmission electron microscopy (TEM). The presence of the fluorescent CLCN/siRNA complexes in the cytoplasm was observed as early as 2 h post treatment by confocal fluorescence imaging analysis. A significant inhibition of gene expression was detected in both EGFP-stable clones and transiently-transfected lung cancer H1299 cells treated with CLCNs/siEGFP complexes 24 hour after transfection compared to the untreated and non-specific CLCN-siRNA controls. Biodistribution analysis showed that the CLCNs were successfully delivered to various organs including liver and lung and into the subcutaneous human lung cancer H1299 tumor xenografts in mice 24 h after systemic administration by tail vein. These results suggest that CLCNs are suitable for the delivery of small synthetic RNAi-based therapeutics in vitro and in vivo. CLCNs are a unique and advanced delivery system capable of protecting siRNA from degradation and efficiently delivering siRNA to the cytoplasm where effective gene silencing is achieved.(This study is partially supported by NIH/NCI grants Lung SPORE 5P50CA070907 and R01CA176568, a CPRIT Grant and a MDACC Moonshot Program Grant. Citation Format: Emanuela Gentile, Taro Oba, Jing Lin, Ruping Shao, Feng Meng, Xiaobo Cao, Dong Cai, Jack A. Roth, Lin Ji. A novel cationic liquid crystalline nanoparticle for the delivery of synthetic RNAi-based therapeutics. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3906.