噬菌体展示肽修饰的多重靶向泡囊共载药系统用于脑胶质瘤的治疗研究

Chemotherapy of malignant glioma remains a most formidable challenge due to the low drug transport across the blood-brain barrier (BBB) or blood-brain tumor barrier (BBTB), poor penetration into the tumor tissue,and multidrug resistance (MDR) of glioma stem cells (GSCs). It has been reported that transferrin receptor (Tf-R) highly overexpressed both in BBB and in malignant glioma cells and nestin receptor overexpressed both in GSCs and in tumor vascular endothelial cells. Based on that, in this research we are engaged in developing a novel multi-targeting polymersomes nanocarrier which could enable drug to transport across the BBB or BBTB, target the brain glioma cells and GSCs and overcome the MDR of the GSCs. By conjugating with TR-12 peptide and AS-7 peptide(identified by phage display screening method) which can be recognized and binded by the Tf-R and nestin receptor with high affinity respectively, the nanosystem is expected to penetrate the BBB or BBTB, and home to the malignant glioma cells and GSCs. Via co-delivery resveratrol(RES) and doxorubicin (DOX),the above nanosystem is expected to overcome the MDR of the GSCs. The nanosystem would be carefully disigned and characterized by detecting particle size,zeta potential and so on, and the targeting efficiency and mechanism would be systematically assessed in vitro at the cellular level and in vivo in intracranial xenograft nude mice model. The MDR-overcoming efficiency and mechanism of the above nanosystem would be also evaluated by detecting ATP-Binding cassette such as multidrug resistance protein 1 (MDR 1) and multidrug resistance associated protein 1 (MRP 1) and caspase-3 mRNA expressing level.Taken together,we would like to demonstrate the anti-glioma efficacy and MDR-overcoming availability of the above polymersomes nanosysytem at cellular level and small animal level.

针对脑胶质瘤化疗中药物"入血难入脑，入脑不入瘤"及脑胶质瘤干细胞多药耐药(MDR)等关键性问题，设计构建多重靶向聚合物泡囊递药系统。本课题拟以转铁蛋白受体和Nestin受体为分子作用靶点，以新型噬菌体展示肽为导向性分子修饰生物可降解的聚合物泡囊构建兼具血脑屏障、脑胶质瘤及脑胶质瘤干细胞(GSCs)等多重靶向作用的新型纳米递药系统；同时通过化疗药物与增敏剂的联合应用逆转GSCs的MDR。采用现代药剂学技术对该系统制备方法进行筛选和优化；利用DLS法及X衍射等方法对该系统物理化学参数进行表征；采用细胞器共定位技术、流式细胞术及活体成像等实验评价该系统胞内转运情况及靶向性，阐明其入胞途径和机制；通过PCR技术及琼脂糖凝胶电泳等手段考察该共载药系统对GSCs的ABC耐药蛋白以及mRNA表达水平的影响，探讨其逆转MDR的机理。从细胞水平和整体动物水平评价该载体系统靶向治疗肿瘤和逆转MDR的应用。

该课题以开环共聚方法合成了末端功能化的嵌段聚合物材料，包括羧基封端的 PEG-PTMC 嵌段共聚物 (HOOC-PEG-PTMC) 和N-羟基琥珀酰亚胺基团封端的PEG-PTMC (NHS-PEG-PTMC)，并用以设计构建了聚合物泡囊递药系统；并以新型噬菌体展示肽为导向性分子进行了表面修饰构建了包载化疗药物与增敏剂的具有多重靶向作用的新型纳米递药系统。利用动态光散射实验对该纳米系统的物理化学参数进行了表征;采用激光共聚焦显微镜共定位技术、流式细胞术及活体成像等实验评价了该系统胞内转运情况及体外靶向特性，阐明了其入胞途径和机制；在此基础上初步评价了聚合物泡囊系统靶向治疗肿瘤和逆转肿瘤多药耐药的有效性。已发表相关SCI论文2篇，累计影响因子>10. 目前正在撰写SCI论文2篇。本课题圆满完成了预定的各项研究任务，实现了预期目标。