基于胞内和胞外双重酶敏感的智能型自组装siRNA递送系统及其抗肿瘤转移治疗效应

The lack of anti-metastatic treatment is one of the reasons for cancer-induced death. This project is to study the role of intelligent drug delivery systems on treatment of metastatic breast cancer. Here,we design the PEG-PEP-PCL polymer containing an extracellular matrix metalloproteinase (MMP-2) sensitive peptide fragment and the PCL-SS-Rx polymer containing intracellular glutathione (GSH) sensitive disulfate, and construct the self-assembly dual enzyme-sensitive core-shell polymer micelles as carriers for in vivo delivery of PAR-1 siRNA. Also, this polymeric micelles will be used as a carrier for in vivo co-delivery of paclitaxel and PAR-1 siRNA. PEG-modified is used to achieve long circulation in circulation, high concentration of MMP-2 in tumor tissue interstitial will help for the removal of PEG from nanomicelles by enzymatic degradation, and an enhanced intacellular uptake of PEG-detached nanoparticle will be happened. With the GSH increased in endosomes/lysosomes, more degradation of disulfide bonds will facilitate the release of siRNA from complexes into cytoplasm and exhibit gene silencing efficacy. The efficacies of the micelleplex nanoparticles and molecular mechanisms underlying for interfering target gene expression,inhibiting cellular proliferation and migration will be systematically evaluated in various types of breast cancer cells. The abilities of the micelleplex nanoparticles to inhibit tumor growth and metastasis in vivo will be evaluated in orthotopic transplantation nude mouse models of metastatic breast cancers. This project is innovative and promising.

抗肿瘤转移治疗手段的缺乏是恶性肿瘤致死的重要原因之一。本项目以转移性乳腺癌为模型，利用肿瘤转移发生必需的基质金属蛋白酶(如MMP-2)激发智能型载药系统靶向递药。利用设计合成的含MMP-2酶底物多肽的PEG-PEP-PCL和含谷胱甘肽敏感二硫键的PCL-S-S-Rx 材料超分子混合自组装形成核-壳型聚合物胶束，以PAR-1为靶标构建双重酶敏感胶束/siRNA复合纳米粒。该系统利用PEG修饰实现体内长循环，利用肿瘤组织间质MMP-2酶降解断裂脱除PEG链，暴露精氨酸(R)正电荷促进细胞内吞。利用胞内GSH升高断裂二硫键促进复合物解散释放siRNA进入胞浆发挥药效。以转移性乳腺癌细胞及裸鼠原位移植瘤为模型，分别从分子、细胞、组织和动物水平系统考察复合纳米粒干扰靶标基因表达、抑制细胞增殖和迁移的能力，阐明肿瘤转移治疗药物的递送规律和分子机制。

本研究设计开发了多种胞外、胞内敏感可断裂或结构转变的材料，如：PCL-R15，PCL-SS-R15、PCL-PEP-PEG、PEG-Hy-Chol、ssGLCL、mPEG‑b‑PHis‑b‑PEI，利用这些两亲性材料在水相介质中形成自组装纳米颗粒并包载siRNA，构建了多种不同处方组成的胞外胞内敏感型纳米联合载药系统，以期实现抗肿瘤治疗效应改善。体内外的抗肿瘤评价结果表明，这些胞外、胞内敏感型载药系统具有较好抗肿瘤治疗效应。同时，本研究还阐明了结构-效应相关性及抗肿瘤分子作用机制，揭示了抗肿瘤治疗药物制剂的设计规律，并为进一步应用研究提供理论基础和实践参考。目前，该课题相关研究结果已发表在《International Journal of Pharmaceutics》、《Journal of Controlled Release》、《European Journal of Pharmaceutical Sciences》、《Nanoscale》《ACS Applied Materials & Interfaces》等杂志上，共发表SCI学术论文6篇及国内核心期刊6篇（均标注基金号81473158），申请专利1项，培养博士生2名，硕士生7名。