肿瘤靶向的高分子纳米载体用于小干扰RNA药物输送的研究

Small interfering RNA (siRNA) has emerged as a promising candidate for the treatment of numerous diseases including cancer in recent years. However, targeted delivery of siRNA to specific tissues and cells remains as one of the key challenges in the development of RNA interference as a therapeutic application. Previously, we have reported a cationic lipid assisted poly(ethylene glycol)-b-poly(d,l-lactide) (PEG-PLA) nanoparticle system for efficient siRNA encapsulation and delivery. In this project, we will conjugate N-acetylgalactosamine and anti-Her2 single-chain variable fragment (ScFv) to the PEG-PLA nanoparticles to targeted deliver siRNA to hepatocyte and Her2-expressing breast tumor cells, respectively. The preparation and property of the targeted delivery system, cellular uptake of targeted nanoparticles by cancer cells, gene silencing efficacy and cell apoptosis will be investigated in this project. Furthermore, the accumulation and distribution of siRNA in tumor site will be studied to determine if the targeted nanoparticles could specific deliver siRNA to target tissue and cells. At last, the promoted RNA-interfering efficiency and enhanced inhibition of tumor growth following the introvenous delivery of siRNA by the nanoparticles will be verified in vivo. This project will provide novel strategy for the development of in vivo siRNA delivery system.

小干扰RNA（siRNA）是最近几年基于RNA干扰的原理快速发展的潜在新型药物，在肿瘤治疗中具有高特异性和高效性，但其研发严重受制于体内给药载体及相关技术的研究。基于生物可降解高分子的纳米载体的研究和应用有望突破其临床应用的这一关键瓶颈。本项目拟在前期基础上，用乙酰半乳糖胺、单链片段抗体修饰由脂质材料辅助制备的聚乙二醇-聚乳酸载药纳米颗粒，发展肿瘤靶向的siRNA纳米给药系统，实现对肝癌细胞和Her2阳性乳腺癌细胞的高效siRNA输送。项目将制备供靶向修饰的高分子，优化纳米颗粒的制备方法，研究其纳米特性，被靶细胞摄取和对靶基因的沉默及效应；进一步在荷瘤小鼠体内研究静脉给药后，靶向载药纳米颗粒在肿瘤的富集和分布，进入肿瘤细胞的能力，及对肿瘤生长的抑制，证明其RNA干扰机制。本项目的研究将为siRNA药物的研发和获得具有自主知识产权的siRNA输送的高分子纳米载体打下坚实基础。

本项目旨在构建肿瘤靶向的 siRNA 纳米给药系统，揭示其载体内的循环、分布、摄取等行为，并在体内外系统评价其功效，为发展高效 siRNA 输送的高分子纳米载体提供实验和理论依据。主要成果包括：（1）利用单链片段抗体修饰包载siRNA的聚乙二醇-聚乳酸载药纳米颗粒，发展肿瘤靶向的 siRNA 纳米给药系统，实现对Her2阳性乳腺癌细胞的高效 siRNA 输送；（2）提出了肿瘤微环境激活的靶向纳米体系，实现了纳米载体的靶向递送；并在系统研究了siRNA纳米颗粒的特性与其体内功效关系的基础上，设计了肿瘤微环境高表达基质金属蛋白酶激活的靶向siRNA纳米给药体系，通过靶向递送siRNA药物到肿瘤细胞，增强对肿瘤生长的抑制。本项研究的成果Advanced Materials、Advanced Functional Materials、Biomaterials、Advanced Healthcare Materials等杂志发表研究论文12篇，申请发明利5项，超额完成了预期目标。