项目名称： 具有肿瘤双重靶向及内涵体逃逸功能的高siRNA载量纳米粒的制备及形成机制研究

项目编号： No.81502675

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 医药、卫生

项目作者： 李志平

作者单位： 中国人民解放军军事科学院军事医学研究院

项目金额： 18万元

中文摘要： 如何显著提高靶细胞浆内水平是限制siRNA临床应用的关键所在。siRNA聚合体由纯siRNA组成，克服了现有载体siRNA载量低的缺陷，成为siRNA临床应用的希望所在。然而，非特异性及内涵体降解作用导致其到达靶细胞浆内的siRNA水平有限。本课题拟将配体及PEG修饰的阳离子聚合物PEI与siRNA聚合体复合，构建具有长循环靶向及内涵体逃逸能力的高siRNA载量纳米粒（DTNHLE）。DTNHLE将在配体PHSCNK肽和YIGSR肽双重介导下靶向肿瘤组织，并经内吞高效透膜，在内涵体中酸及酶作用下解离出PEI，获得内涵体逃逸能力，siRNA聚合体则在胞浆Dicer酶作用下释放大量活性siRNA，实现靶细胞浆内siRNA水平的显著提高。本项目将综合运用siRNA聚合技术、长循环修饰技术、双重靶向技术以及内涵体逃逸技术，探索构建DTNHLE的可能性及其形成机制，为推动其临床应用奠定基础。

中文关键词： C20_皮肤及黑色素瘤；小干扰RNA；高载量纳米粒；内涵体逃逸；肿瘤靶向

英文摘要： An ideal anti-tumor effect is not yet obtained even if siRNA has been delivered into target cells, which is believed related to the degradation of siRNA by acid and enzymes in endosomes/lysosomes and insufficient siRNA for gene silencing in cytoplasm. So, it is crucial to deliver sufficient siRNA into cytoplasm to realize gene therapy. The presence of siRNA conglomerations, which are composed by almost entire siRNA, shows hope for sufficient siRNA in cytoplasm. Unfortunately，the efficient siRNA delivery of this system into cytoplasm is invalidated by lack of tumor targeting and thereafter endosomal degradation. To acquire satisfactory gene therapy，dual tumor-specific targeting nanocarriers with high siRNA loading and endosomal escape ability (DTNHLE) will be constructed by combining siRNA polymerization with ligands and PEG decorated polyethyleneimine (YIGSR/PHSCNK-PEG-PEI). These nanocarriers will get tumor sites under the guidance of dual targets in vivo, then be internalized by tumor cells because of the high affinity between receptors and ligands and transported into endosomes. Polyethyleneimine，a kind of cationic polymers, will be subsequently liberated after degradation of YIGSR/PHSCNK-PEG-PEI by acid and enzymes in endosomes and destruct the membrane of endosomes via proton sponge effect. siRNA polymers are uncaged into cytoplasm and sufficient of siRNA is released in cytoplasm under the action of Dicer. DTNHLE will be constructed by using siRNA polymerizing, long-circulating, dual tumor-specific targeting and endosomal escaping technology combinedly. The formation mechanism of DTNHLE will also be investigated to obtain the optimal DTNHLE. Sufficient siRNA delivery into cytoplasm of tumor cells and desirable inhibition of tumor are expected in this study.

英文关键词： Melanoma;Small interfering RNA;Nanocarriers with high drug loading;Endosomal escape;Tumor-specific targeting