RGD肽修饰的高稳谷胱甘肽(GSH)响应型胶团的构建与靶向机制研究

It is a focus of the anticancer drug carrier research to transport the drug to the focal tissues precisely with fixed position, so that local lesion could be treated locally. In this project, a kind of glutathione (GSH)-mediated intracellular drug-loaded micelles would be developed, which can actively target at cancerous cells and neovascular endothelial cells, with the introduction of RGD peptide and disulfide bond based on polyethylene glycol-polymethyl methacrylate (PEG-PMMA) substrate. The intra- cellular process of triggered release of the drug would be investigated by using doxorubicin (DOX) as a drug model, and GSH in PBS solution would be used to simulate the intracellular and extracellular redox potential difference. What's more, cancerous cells and neovascular endothelial cells would be simulated with melanoma HELA cells and human umbilical vein endothelial cells serving as models respectively, and the influence of RGD peptide and GSH inducing effect on the micelle transmembrane ability and targeting ability would also be studied. Through the study of the DOX localization intracellular and in tissues, and the effects of the micelles on the tumor suppressing function of DOX in the B16 tumor-bearing mice models,the synergy can be probed between the active targeting capacity of RGD peptide and disulfide bond crosslinked structure to micelles and GSH triggered intracellular DOX release. And this study can provide practical basis for the development of the targeting mechanism of this micelles, and offer new ideas for the construction of functionalized anticancer drug carriers.

将药物定向输送到病灶组织，以实现局部病变局部治疗是抗肿瘤药物载体研究的热点。本项目以聚乙二醇-聚甲基丙烯酸甲酯(PEG-PMMA)为底物，通过RGD肽和二硫键(SS)交联结构的引入，构建一类对肿瘤细胞及其新生血管内皮细胞具有主动靶向性，且能够实现细胞内药物GSH触发释放的高稳联合型胶团。本研究采用阿霉素(DOX)为药物模型，以GSH的PBS溶液模拟细胞内外氧化还原电位差异，进行GSH触发DOX释放过程研究。以人子宫颈癌细胞（HELA）和人脐静脉内皮细胞（HUVEC）为模型，模拟肿瘤细胞及其新生血管内皮细胞，探索RGD肽和GSH诱导对胶团跨膜能力和靶向性能的影响。通过细胞和组织中DOX的分布研究，载DOX胶团对小鼠黑色素瘤（B16）荷瘤小鼠模型肿瘤生长抑制性能研究，探索RGD介导和GSH诱导对胶团靶向性能的协同作用，为该类胶团的靶向机理研究提供依据，为多功能化抗肿瘤药物载体的构建提供新思路。

本项目基于二硫键的谷胱甘肽（GSH）敏感性以及RGD肽对肿瘤细胞的主动靶向性，以聚乙二醇（PEG）为底物构建了一系列GSH敏感型以及RGD肽修饰的药物载体材料。① 构建了GSH敏感型mPEG-PMMA-SS两亲聚合物胶团，并评价了该胶团的载药性能、稳定性、形态。以HELA细胞和巨噬细胞RAW264.7为模型研究了细胞水平的靶向性能。研究显示mPEG-PMMA-SS胶团粒径在200 nm以下，粒径分散较为均匀，药物包载稳定性较佳，且具有良好的GSH敏感性。细胞内的药物释放和细胞毒性研究显示该胶团在细胞内高GSH水平下能够完成药物的控制释放，载体本身细胞毒性较低。② 基于RGD的主动靶向性构建了一种刷形的两亲聚合物（PMMA-b-PPEGMA-RGD），研究显示由其构建的胶团具有较高的稳定性能，实验通过评价其细胞毒性（SGC7901胃癌细胞）研究，初步确定了其对肿瘤细胞的主动靶向能力。在该部分的研究过程中发现胍基可以与低聚的聚乙二醇形成氢键结构，该作用力在PMMA-b-PPEGMA-RGD表面形成氢键网络使得胶团具有高度的稳定性。这种氢键的形成有望成为聚合物结构修饰的一种简便的方案。③ 基于mPEG-PMMA-SS和PMMA-b-PPEGMA- RGD构建了复合胶团，通过细胞毒性、内吞抑制剂的影响、RGD肽的影响等研究，证明复合胶团中RGD介导和GSH敏感性具有一定的协同作用。④本课题组还开展了其他类型的GSH敏感型、光敏感型、多重敏感型药物载体体系的研究，并获得了一些有意义的结果。⑤ 发表论文15篇药物载体相关的论文，其中SCI收录论文3篇，1篇文章已经录用。