抗炎症纳米基因载体的构建及炎症微环境的转染行为研究

Vector-mediated gene therapy is a powerful approach for tumor therapy. It has been well recognized that gene carriers will be exposed to an inflammatory microenvironment specific to tumors. However, reflecting on most of the previous research, we find that the effect of inflammatory microenvironment on gene transfection has been surprisingly ignored. In this proposal, an anti-inflammatory transgene nano-vector is designed by self-assembly of amphiphilic ascorbyl palmitate (AP) containing dihydroxy and a phenylboronic acid-modified cationic polyaspartic acid derivative. This assembly will be employed to load plasmid DNA and resveratrol (a natural polyphenol with anti-inflammation and anti-tumor activity). It is anticipated that in vivo circulation time of nano-carrier will be improved due to the nature of negative charged AP, while the existing postitively charge proteins in the inflammatory zone exactly make the AP-capped vector targetable to this tumor microenvironment. Under the inflammatory environment, the surface of nano-carrier will reverse to positive charge, thus promoting endocytosis process due to the degradation of AP by the esterase. Eventually, the gene transfection efficiency will be enhanced. The aim of this project is to investigate the gene transfection behavior of an anti-inflammatory gene nano-vector under inflammatory micromilieu, and the gene transfection and tumor therapy efficiency will be evaluated in animal model. This proposal is expected to provide a new concept for the construction of responsive nano-vector used in inflammatory environment.

载体介导的基因治疗是肿瘤治疗的一个重要手段，治疗过程中基因载体会遭遇炎症微环境，然而以往研究大多忽视了肿瘤炎症微环境对载体功效的影响。本项目拟通过含有双羟基的两亲性抗坏血酸棕榈酸酯（AP）与苯硼酸修饰的阳离子聚天冬氨酸衍生物作用形成组装体，然后将DNA及白藜芦醇装载其中，形成具有抗炎症功能的纳米基因载体。期望带负电AP的引入提高纳米载体的体内循环时间，并且由于炎症环境沉积的正电荷蛋白，使所构建的载体具有炎症靶向性，在肿瘤炎症微环境，AP自组装体解体，释放抗炎症药物，裸露的纳米载体表面的正电性促进基因对靶细胞的内吞，提高转染效率。课题将系统考察其在肿瘤炎症微环境下对细胞转染的影响，同时构建炎症性乳腺癌肿瘤模型，通过体内实验评估抗炎症纳米基因载体在肿瘤炎症微环境下的胞吞效率、基因转染效率以及对肿瘤的治疗效果。为炎症环境下新型智能纳米基因载体的构建提供新思路。

载体介导的基因治疗是肿瘤治疗的一个重要手段，治疗过程中基因载体会遭遇炎症微环境，然而以往研究大多忽视了肿瘤炎症微环境对载体功效的影响。本项目通过含有双羟基的两亲性抗坏血酸棕榈酸酯（AP）与苯硼酸修饰的阳离子聚天冬氨酸衍生物作用形成组装体，然后将DNA及白藜芦醇装载其中，形成具有抗炎症功能的纳米基因载体。实验表明带负电AP的引入提高纳米载体的体内循环时间，并且由于炎症环境沉积的正电荷蛋白，使所构建的载体具有炎症靶向性，在肿瘤炎症微环境，AP自组装体解体，释放抗炎症药物，裸露的纳米载体表面的正电性促进基因对靶细胞的内吞，提高转染效率。激光共聚焦成像及体外细胞毒性实验表明，该纳米体系在炎症环境下的细胞胞吞量是非炎症环境下的1.5倍。炎症环境下该纳米体系的胞吞量是基因纳米复合物PEI-PBA/DNA的6倍。动物关节炎模型显示该纳米载体使得抗炎症效率提高了一倍多。同时基于肿瘤微环境，构建了一系列敏感性高载药量（90%）的肿瘤特异靶向性纳米载体，极大提高了基因转染效率以及对肿瘤的治疗效果。为炎症环境下新型智能纳米基因载体的构建提供新思路。