用于肺部给药的基因/化疗药共传递载体的构建及抗肿瘤研究

Compared with intravenous infection, pulmonary delivery through intratracheal aerosol spray has the advantages of minimal drug loss, low toxicity, precise quantization, avoiding degradation and saving costs. Based on the direct pulmonary delivery, the cationic polymer co-delivery carriers, which co-deliver gene and chemotherapeutics, will be employed for the therapy of lung cancer. Firstly, degradable multi-armed poly (L –glutamic acid)-graft-OEI (MP-g-OEI) copolymers are synthesized by grafting different kinds of oligoethylenimine onto a determinate multi-armed poly (L-glutamic acid) (PBLG) backbone. Secondly, MP-g-OEI graft with DOX and targeting ligand by covalent interaction, and then complex with gene by electrostatic interaction, finally, the DOX-loaded and gene complexed particles are obtained. We will discuss the cytotoxicity, transfection efficiency and mechanism of these new carriers through cells experiments, and then evaluate this new co-delivery carrier system through pulmonary retention and metabolism behavior, at last, verify the effect of this co-delivery carrier system on the inhibition of lung cancer and further reveal the inhibitive mechanism. The target of this project is to prepare a kind of in vivo degradative polymer co-delivery carrier system, especially with the outstanding advantages of safety, low toxicity, and high transfection efficiency. Moreover, the polymer carriers will be delivered into lung through intratracheal aerosol spray. We are involved with trying to explore the optimized therapy for lung cancer, and set a base for further clinical application of polymer.

经气管喷雾肺部直接给药与静脉注射给药相比具有药物损失量少、低毒、定量、避免药物降解、节约成本等优点。本项目借助气管喷雾肺部直接给药的方法，采用高分子载体共传递基因和化疗药物，对小鼠肺癌模型进行治疗。首先采用聚谷氨酸衍生物接枝不同种类的小分子量聚乙烯亚胺制备出多臂骨架可降解的阳离子聚合物（MP-g-OEI），将阿霉素（DOX）和靶向配体键合到MP-g-OEI上，通过静电作用与基因复合得到共载基因和DOX的纳米复合物颗粒。借助细胞实验，探讨此载体的细胞毒性、转染性能及转染机理，对共传递载体系统进行体内肺部滞留及代谢行为研究，最后验证该高分子载体共传递基因和化疗药物对体内小鼠肺癌模型的抑制作用，并进一步揭示其抑制机理。本项目的目标是制备出一种安全、低毒、高效、适合体内应用的高分子共传递载体系统，经气管喷雾肺部直接给药实现对肺癌有效治疗，为高分子载体在临床应用奠定基础。

与静脉给药相比，肺部给药具有其独特的优势，由于肺部组织拥有比较大的吸收表面积可以使基因或药物滞留在肺部从而发挥作用，且对正常组织毒副作用低。本项目制备出几种适合气管肺部喷雾给药和体内应用的高分子药物/基因共传递载体，首先采用聚乙烯亚胺（PEI）阳离子载体，将化疗药物通过不同的方式与PEI键合，然后通过静电复合作用将siRNA进行复合制备出复合物颗粒。将复合物颗粒采用气管喷雾注射器直接喷射到肺中，随后，化疗药物阿霉素（DOX）在肿瘤细胞低pH内涵体环境下释放进入到细胞核中发挥药效；阳离子聚合物载体发生裂解代谢出体外，siRNA被释放出来参与后续的转染过程并发挥基因沉默作用，从而引起细胞的凋亡等机制，从而起到抗肿瘤作用。进一步地，为降低细胞毒性，采用聚谷氨酸载体为基础，制出结构简单、制备过程容易、有效且实用的高分子纳米载体，然后将小分子化疗药物阿霉素与顺铂通过不同的方式复合与络合到载体上，从而制备出高分子纳米载药颗粒。纳米颗粒通过气管喷雾注射器直接喷射到肺中，随后，化疗药物DOX和CDDP在肿瘤细胞低pH内涵体环境下缓慢释放进入到细胞核中发挥药效；高分子纳米载体发生降解代谢出体外，最终对肺转移癌起到抑制和治疗的作用。该项目的顺利实施，为肺转移癌的治疗提供一种新的治疗方法，同时为高分子载体在临床上应用提供基础。