基于肿瘤归巢肽介导的脑胶质瘤多靶点靶向纳米递药系统构建与评价

Glioma is the most common malignant tumor of the nervous system. Active targeted therapy against glioma is a worldwide problem. It is widespreadly concerned of the research on multi-target therapy of glioma basing on multifunctional target nano drug delivery system. Because of the specific homing ability between Pep-1 peptide and glioma cells as well as between CGKRK peptide and glioma neovascular, polyethylene glycol-polylactic acid-glycolic acid block copolymers (PLGA-PEG) nanoparticles were decorated with both Pep-1 peptide and CGKRK peptide to develop multiple targeted nano-drug delivery system in this study. Therefore, drugs loaded into the multiple targeted nano-drug delivery system could be delivered into glioma cells and glioma neovascular endothelial cells simultaneously. The anti-glioma effects are cooperated by two aspects. One is the destruction of glioma blood vessels, cutting the glioma nutrition supply chain and "starving to death" of glioma cells and tissues. The other aspect is that the drugs are directly imported into glioma cells by the multiple targeted nano-drug delivery system and kill glioma cells or glioma tissues. Thereby it can improve the therapeutic effect and reduce dosage, reduce side effects of chemotherapy drugs. This study can provide one novel target strategy of glioma treatment through drug carrier system of pharmaceutics, which is of positive significance to eventually overcome glioma.

脑胶质瘤是最常见的神经系统恶性肿瘤。针对脑胶质瘤的主动靶向治疗是世界性难题。以胶质瘤多个环节为靶点的多功能靶向纳米递药系统研究正受到广泛关注。本课题利用Pep-1肽对胶质瘤细胞和CGKRK肽对胶质瘤新生血管的特异性归巢能力，将聚乙二醇-聚乳酸-羟基乙酸嵌段共聚物(PLGA-PEG)纳米粒同时用Pep-1肽和CGKRK肽进行共修饰，构建针对胶质瘤细胞和胶质瘤新生血管的多靶点靶向纳米递药系统，特异性地将药物同时递送到胶质瘤细胞和胶质瘤新生血管内皮细胞。一方面通过破坏胶质瘤血管，切断胶质瘤的营养供应链，"饿死"胶质瘤细胞和组织。另一方面，将药物直接导入胶质瘤细胞与之接触，直接杀死胶质瘤细胞和组织。从而提高胶质瘤的治疗效果，降低给药剂量，减轻毒副作用。本研究可为从制剂角度通过载体系统来寻求多靶点抗胶质瘤提供新思路和新方法，对最终攻克脑胶质瘤具有积极意义。

脑胶质瘤是颅内最常见的原发性恶性肿瘤，发病率高、患者存活期短。目前临床上的治疗分为手术切除、放疗和化疗，但是胶质瘤细胞呈浸润性生长，与正常脑组织界限不明显，所以手术难度大、风险高。化疗手段由于血脑屏障(blood-brain barrier, BBB)和血瘤屏障(blood-brain tumor barrier, BTB )的存在，限制了药物递送到胶质瘤内部，而且化疗药物选择性低、渗透能力弱、入胞效率低等成为其提高疗效的障碍。近年来，纳米递药系统由于其缓释、靶向性和生物相容性等优点而备受关注。将纳米递药系统进一步通过配体修饰，可增强其对胶质瘤部位细胞及新生血管的靶向性，增加细胞的摄取，降低对正常细胞的毒性，从而提高治疗效果。.本课题以PTX为模型药物，利用Pep-1肽对胶质瘤细胞和CGKRK肽对胶质瘤新生血管内皮细胞的特异性归巢能力，将聚乙二醇-聚乳酸-羟基乙酸嵌段共聚物(PLGA-PEG)纳米粒同时用Pep-1肽和CGKRK肽进行共修饰，构建针对胶质瘤细胞和胶质瘤新生血管的多靶点靶向纳米递药系统，特异性地将药物同时递送到胶质瘤细胞和胶质瘤新生血管内皮细胞。一方面通过破坏胶质瘤血管，切断胶质瘤的营养供给链，“饿死”胶质瘤细胞和组织。另一方面，将药物直接导入胶质瘤细胞与之接触，直接杀死胶质瘤细胞和组织。从而提高胶质瘤的治疗效果，降低给药剂量，减轻毒副作用。.本论文首先合成了Pep-PEG-PLGA和CGKRK-PEG-PLGA，采用乳化溶剂挥发法制备了Pep-1和CGKRK多肽共修饰的纳米粒Pep&CGKRK-NP (以下简称为PC-NP)，经检测，纳米粒平均粒径在100 nm左右，分布均匀。PC-NP-PTX的包封率与载药量分别为81.7 ± 2.7%和3.5 ± 0.1%。C6细胞和HUVEC细胞摄取实验表明Pep-1和CGKRK的修饰能增加C6和HUVEC细胞对纳米粒的摄取，而且纳米粒载体对C6和HUVEC均没有造成显著毒性反应。细胞毒性实验、肿瘤球生长抑制实验、小管形成实验和细胞迁移实验证明了PC-NP-PTX能增强体外抗胶质瘤活性。近红外活体成像实验和胶质瘤组织分布实验证明了Pep-1和CGKRK的修饰能增强纳米粒对肿瘤部位的靶向性。在药效学实验中，PC-NP-PTX显著延长了荷瘤小鼠的生存时间。初步安全性实验显示PC-NP体内安全性良好。