负载多西紫杉醇的基质金属酶2&9和程序性死亡分子配体-1双靶向纳米投递体系在胃癌治疗中的应用与评价

The situation of gastric cancer prevention and control has long been stern in our country; therefore, to improve the curative effect of gastric cancer is the target of Chinese tumor workers. In recent years, several nano-formulation of Taxanes—— one of the most commonly used chemotherapy agents in gastric cancer, have already completed the clinical transformation；the inhibitors to programmed death-1 and its ligand molecules-1 (PD-1/PD-L1) have made valuable contributions in a wide variety of tumor immunotherapy. Under these background, based on the established targeted delivery carrier for matrix metal enzyme 2&9, the present research proposed to establish the matrix metal enzyme 2&9 and PD-L1 dual targeted delivery system, and then load docetaxel for the treatment of gastric cancer, with hopes of improving the curative effect of gastric cancer through more accurate tumor targeting drug delivery and the combination of chemotherapy and immunotherapy..In the research, the effect of the nanoparticles in gastric cancer treatment will be evaluated, and the mechanism of the potential advantage will also be explored through experiments in vivo and in vitro, in an attempt to provide some scientific basis for the future clinical application of active targeting nano-delivery system and the combination of docetaxel and monoclonal antibodies to PD-L1 in gastric cancer.

长期以来我国的胃癌防治形势严峻，提高胃癌的疗效是我国肿瘤工作者追求的目标。近年来，胃癌最常用的化疗药物之一，紫杉类药物的几种纳米剂型已经完成了临床转化；针对程序性死亡分子-1及其配体（PD-1/PD-L1）的抑制剂在多种肿瘤的免疫治疗已有建树。在上述研究背景下，基于已经建立的基质金属酶2&9为靶点的靶向投递载体，本课题拟建立基质金属酶2&9和PD-L1双靶向的纳米投递体系，再负载多西紫杉醇用于胃癌的治疗，希望通过更精确的肿瘤靶向性药物投递、化疗药物与免疫治疗药物的联合应用来提高胃癌的疗效。本课题将通过体内外实验评估此纳米粒子对胃癌的疗效并对其潜在的疗效优势进行机制探讨，旨在为主动靶向的纳米药物、多西紫杉醇与PD-L1单抗联用在胃癌中的未来临床应用提供一些科学依据。

背景:.多西他赛(DOC)作为一种经典的化疗药物在多种肿瘤的治疗，包括胃癌中被广泛应用.然而,由于药物本身的低溶解度导致DOC的应用受到较大程度的限制.在我们的研究中,计划构建一种多功能的纳米颗粒递送载体,不仅使药物能有效的递送到靶细胞,而且能够减少化疗药物的副反应,提高程序性死亡分子配体-1（PD-L1）单克隆抗体（mAb）与化疗药物联用的协同效应。.主要研究内容:.首先使用开环共聚作用合成聚乙二醇-聚己内酯（PCL-PEG）纳米颗粒,再将PD-L1单克隆抗体偶联在合成的PCL-PEG上，最后将DOC包载到纳米颗粒内部。我们检测了制备好的纳米递送载体的抗体偶联效率,粒径分布,ζ电位,药物的包埋效率,载药能力,以及药物在纳米颗粒中的释放参数曲线等。根据PD-L1分子在不同胃癌细胞株上表达水平不同，我们构建了PD-L1分子高表达和低表达的细胞系,研究纳米递送颗粒在不同细胞系中的细胞摄取水平,细胞毒性作用以及细胞凋亡等相关实验。.结果:.通过体外实验，我们研究了DOC-PEG-PCL-mAb纳米材料的结构特征以及生物学特性；XPS证实了PD-L1单克隆抗体成功偶联在了纳米颗粒的表面；细胞摄取的实验结果证实在单克隆抗体存在的情况下,药物摄取的效率会显著提高；三株胃癌细胞系的体外细胞毒性实验证实单克隆抗体对纳米材料内部药物的释放有靶向引导效果。除此之外,我们发现DOC-PEG-PCL-mAb纳米颗粒在肿瘤细胞中可引起明显的细胞凋亡现象，并将细胞周期进程阻断在G2/M期。与对照组相比, DOC-PEG-PCL-mAb纳米颗粒能有效的抑制了微管合成,且该现象在PD-L1高表达的细胞系中更加显著。.结论:.利用PD-L1单克隆抗体修饰的DOC-PEG-PCL-mAb纳米材料在胃癌的治疗方面有很好的生物学和临床应用潜力