甘草“药性调和”介导雷公藤甲素肝靶向智能递药系统增效减毒机制研究

To realize the bioactive efficacy-enhancing and body toxicity-reducing mechanisms of Chinese herbal medicines in preparation process is always the significant emphasis and difficulty in Pharmaceutics of Chinese medicines. Tripterygium wilfordii Hook f. (Lei Gongteng) is a famous Chinese herb to promote blood circulation and remove blood stasis. Triptolide, one of the main bioactive compounds in Tripterygium wilfordii Hook f., exhibits remarkable anticancer effects, while it also results in serious liver tissue injury. The herb pair of Tripterygium wilfordii Hook f. and Glycyrrhiza uralensis (Gancao) is the classic combination of Chinese herbal medicines to enhance efficacy and reduce body toxicity. In previous study, we found that glycyrrhetinic acid, one of the main components in Gancao, could improve the anti-liver cancer efficacy of triptolide and alleviate the side-effects in liver tissue caused by triptolide. More importantly, functional nano-scaled systems could provide a useful delivery vehicle for multiple agents. .Thus, herein we present an idea that the smart nano-drug delivery system (DDS), in combination of tumor active targeting and the controlled drug release strategy in response to tumor micro-environment, benefits to promote the anti-liver cancer efficacy and alleviate the side-effects of triptolide-glycyrrhetinic acid combination. Briefly, this smart nano-DDS takes advantage of the specific recognition between iRGD peptide and over-expressed integrin in liver cancer, as well as the tissue/cell penetration caused by the acidic-sensitive nanoparticle charge-reversal. After both triptolide and glycyrrhetinic acid are simultaneously loaded, its anti-liver cancer efficacy in vitro and in vivo will be evaluated. Meanwhile, the mechanism of side-effect reduction also will be investigated by biochemical indexes and proteomics. In this way, the efficacy-enhancing and body toxicity-reducing mechanisms of triptolide-glycyrrhetinic acid combination could be evaluated by means of pharmaceutical approach. This project will also provide a novel research idea for the application of multiple components combination.

制剂过程的中药增效减毒机制，是中药制剂基础研究的重难点。雷公藤“主疝瘕、除结气”，其主要活性成分雷公藤甲素抗肝癌作用显著但肝损伤较严重。甘草“调和”雷公藤是“异类相制”配伍典范，组分配伍是药味配伍的实质和精髓。申请者前期发现：甘草主要有效成分甘草次酸可增强雷公藤甲素所致肝癌细胞凋亡并减轻正常肝细胞损伤，功能化纳米载体可为组分药物有效传递提供有利途径。故提出假说：构建主动靶向与肿瘤微环境响应策略相结合的多层次智能递药系统，有利于实现甘草次酸与雷公藤甲素联合抗肝癌增效减毒。.本项目拟基于iRGD肽特异性识别肝癌细胞高表达的整合素受体，结合肿瘤酸敏感响应的电荷翻转实现肿瘤穿透，构建具有肝靶向的雷公藤甲素-甘草次酸组分共载“智能化”多级递药纳米系统，从体内外角度探索其抗肝癌减毒增效作用机制，从而揭示制剂技术促进甘草调控雷公藤“毒/效”的多靶点作用机制，为组分中药合理应用提供制剂学研究的新思路。

组分配伍是传统中药配伍的继承和发展，是有毒中药减毒增效的重要方式之一，然而组分药物的靶部位特异性共同传递是限制药物配伍作用的药剂学瓶颈问题。雷公藤配伍甘草是中药“异类相制”减毒增效的典范，其主要成分雷公藤甲素配伍甘草次酸可显著提高抗肝癌作用，缓减肝毒性，但缺乏两者配伍减毒增效分子机制的深入探索以及有效的药物传递途径。.本项目基于雷公藤与甘草配伍减毒增效传统应用及其两者的抗肿瘤作用，分别对雷公藤甲素、甘草次酸单用及两者联合抗肿瘤作用及机制进行了深入研究；由于前期研究发现，肝癌细胞表面高表达甘草次酸结合受体，故将甘草次酸与PEG链连接，作为纳米材料靶头，采用自主合成的具有ROS敏感的单硫键和酸敏感的PBAE内核的环糊精聚合物材料，通过乳化溶剂挥发法将雷公藤甲素物理包载于环糊精-PBAE功能化纳米粒内核，制得雷公藤甲素-甘草次酸共载功能化纳米体系，使其既具有肝癌靶向性，同时又具有肿瘤微环境响应释药特性；采用肝癌HepG2细胞模型、肝癌荷瘤小鼠模型等体内外模型方法进行该共载纳米递药体系的抗肿瘤效率，发现其可显著抑制肿瘤细胞增殖/组织生长，且可避免雷公藤甲素导致的肝损伤和系统毒性，有利于实现雷公藤甲素的“增效-减毒”及对肝癌的特异-高效性治疗。本项目的开展有效阐释了组分配伍结合功能化纳米载体的抗肝癌增效减毒分子机制，为揭示组分中药通过制剂技术实现减毒增效的科学内涵提供新思路。