亚细胞结构靶向药物递释系统构建与评价

The design of drug delivery system about tumor cells’ subcellular structure targeting and drug releasing, has increasingly become the key to highly effective and safe treatment. In this project, glycolipid conjugate is chosen as the nanocarrier core, which is modified with triphenylphosphine (CTPP), or chitosan in low molecular weight, nuclear localization signal (NLS) and aptamer (Apt), to target mitochondria and nucleus in tumor cells, respectively. In the meantime, disulfide bond, ester bond and phosphate diester bond are used as the linkage between chistosan and stearic acid, which can realize fast drug releasing in mitochondria and nucleus, respectively. The relationship between the targeting group modified with different species and conjugation ratios, and the targeting efficiency will be studied. By determining the pH values, GSH levels and concentration of esterase and nucleic acid enzymes in subcellular structure, we will focus on the molecular mechanism between pathophysiological parameters and responsive release at the internal environment of subcellular structures. We aim to illustrate the relevance between the design of drug delivery system and the subcellular structure targeting and drug releasing. By the research of dynamic distribution, dynamic release and pharmacodynamics on tumor cell model and tumor animal model, we further hope to expound the inherent law between subcellular structure targeting and drug releasing of drug delivery system and the therapeutic efficacy in vitro and in vivo. This study will provide new idea, strategy and approach for tumor therapy based on efficient and safe drug delivery system, and then enlarge and expand the tumor therapeutical theory.

肿瘤细胞亚细胞结构靶向和释放的药物递释系统，是实施药物高效安全治疗的关键。本项目选择糖脂嫁接物为载体母核，以三苯基膦修饰，低分子壳聚糖及核定位信号肽、适配体修饰，分别靶向肿瘤细胞线粒体与细胞核，采用二硫键、酯键、磷酸二酯键链接壳聚糖和硬脂酸，实现线粒体、细胞核内药物敏感释放，构建以线粒体、细胞核为代表的亚细胞结构靶向药物递释系统。研究不同类别、不同比例靶向基团修饰与靶向效率之间的相关性。通过测定亚细胞结构的pH值及GSH与脂酶、核酸酶浓度，研究病理生理学参数与内环境敏感释放之间的分子机制。阐明药物递释系统的分子设计与亚细胞结构靶向、释放之间的内在联系。通过模型细胞和模型动物的动态分布、动态释放及药效学研究，探明药物递释系统的亚细胞结构靶向、释放，与细胞药效、体内药效之间的内在规律性，为药物递释系统的高效安全治疗，提供新思路、新策略和新方法，丰富和发展肿瘤治疗理论体系。

肿瘤细胞亚细胞结构靶向和释放的药物递释系统，是实施药物高效安全治疗的关键。本项目针对以线粒体、细胞核为代表的亚细胞结构内环境，设计制备了糖脂嫁接物为载体母核，三苯基膦修饰的线粒体靶向糖脂嫁接物载体，选择阿霉素为模型药物，通过靶向线粒体的高效药物递送，提高体内抗肿瘤疗效；根据肿瘤细胞线粒体的pH弱碱性内环境的特点，以弱酸性药物雷公藤红素为模型药物，构建具有线粒体靶向和弱碱性敏感释放双重功能的药物递释系统。本项目利用糖脂结构特异性细胞核转运通路，构建了具有肿瘤细胞核快速浓集及响应核内活性氧ROS结构敏感变化的载体，实现糖脂纳米给药系统的肿瘤细胞核内高效靶向及快速释放。.研究发现，具有线粒体靶向和线粒体弱碱性敏感释放双重功能的药物递释系统C-P-CSOSA/Cela，可选择性聚集于肿瘤细胞线粒体，响应线粒体pH 8.0弱碱性内环境快速释放Cela，提高线粒体靶点部位药物浓度，大幅度提高抗肿瘤疗效。机制研究结果显示，C-P-CSOSA/Cela可刺激肿瘤细胞活性氧水平快速增加，引起线粒体膜电位降低，促进细胞色素C释放至胞浆，诱导Caspase级联反应，激活促凋亡蛋白Bax，抑制抗凋亡蛋白Bcl-2，诱导肿瘤细胞凋亡。.研究发现，具有细胞核靶向及核内ROS敏感释放双重功能的药物递释系统Ce6-CSOTKSAm/DOX嫁接物胶束具有较好的细胞核靶向性。激光照射时，可使Ce6产生大量ROS。在含有H2O2的释放介质中或激光光照射条件下，均可实现敏感释放。给药系统通过将药物递送至肿瘤细胞细胞核，激光照射条件下Ce6产生ROS，酮缩硫醇键响应性断裂，实现药物的快速释放，且激光照射组小鼠肝中未发现4T1细胞转移灶，显示肿瘤细胞肝转移被抑制。.本项目构建了线粒体、细胞核高效靶向和特定内环境敏感释放的新型药物递释系统，通过模型细胞和模型动物的动态分布、动态释放及药效学研究，探明药物递释系统的亚细胞结构靶向、释放，与细胞药效、体内药效之间的内在规律性，为药物递释系统的高效安全治疗，提供新思路、新策略和新方法，丰富和发展肿瘤治疗理论体系。