肿瘤细胞/亚细胞器双靶向多肽药物载体的设计及其在抑制肿瘤耐药性中的研究

Tumor therapy always suffers from the barrier of drug resistance upon chemotherapy with undersired side effects. In this project, we designed amphiphilic peptide-based matrix metalloproteinase 2 (MMP-2)-triggered tumor cellular/subcellular organelles dual-targeted drug delivery systems to overcome drug resistance. Trinitarian therapeutical stragety will be proposed to ablation of drug resistant cells, i.e., improved cellular uptake of hydrophobic drug in drug resistant cells via MMP-2 responsive drug delivery, combined chemical and photodynamic therapies, and suppression of drug active efflux mediated by decreased expression level of drug resistance related bioactive substances such as adenosine triphosphate (ATP). In vitro studies in terms of the MMP-2 responsive cell targeting, integrity of subcellular organelles, drug uptake and efflux, MTT assay and in vivo antitumor effect will be extensively studied to evaluate the inhibition of drug resistance. Moreover, the relationship among the light irradiation time, the amount of ATP and the cell viability in drug resistant tumor cells will be tested systematically. And the potential mechanism of subcellular organelles destruction in overcoming drug resistance will be proposed. We hope this strategy can open a new window in the design of overcoming drug resistance systems.

肿瘤细胞对药物的耐药性以及药物较大的毒副作用是肿瘤化疗过程中面临的关键问题。本项目拟构建基质金属蛋白酶2（MMP-2）触发的肿瘤细胞/亚细胞器双重靶向的两亲性多肽类药物传递体系用以克服肿瘤细胞耐药性。本项目拟提出“三位一体”的治疗策略杀灭耐药性肿瘤细胞，即通过MMP-2响应性药物传递增加药物在耐药性肿瘤细胞中的内吞；化学治疗与光动力学治疗的联合治疗；降低细胞内的关键活性物质如三磷酸腺苷（ATP）含量，从而降低药物的主动外排。通过体外MMP-2酶响应性的肿瘤细胞靶向、细胞亚细胞器完整性、药物的内吞与外排、毒性测试以及动物体内的抗肿瘤实验系统评估该药物传递体系对肿瘤耐药性的抑制。深入探讨光照条件、细胞内ATP等物质的含量、耐药性细胞存活率之间的关系，深层次地揭示亚细胞器的破坏在抑制肿瘤细胞耐药性中的机制,为新型的抑制肿瘤耐药性体系的设计提供新思路。

肿瘤靶向精准、高效治疗依然是肿瘤研究中的难题，基于多肽的纳米粒子显示出巨大的应用前景。本项目制备了一系列基于肿瘤微环境响应性多肽纳米粒子，通过纳米粒子形貌转变、“逻辑门”、电荷反转等策略，实现了肿瘤组织/亚器官靶向的药物治疗与成像、耐药性肿瘤细胞治疗。本项目为设计高效、安全的肿瘤靶向纳米传送体系提供了新的思路。本研究得到了以下代表性结果：. 1.构建了基于多肽的肿瘤线粒体靶向药物传递系统。该载药多肽自组装体可靶向破坏耐药性肿瘤细胞线粒体，大幅降低细胞内ATP水平，抑制ATP依赖的药物外排行为，从而克服肿瘤细胞耐药性。. 2.构建以肿瘤线粒体为模板的金纳米粒子富集体，有效地激发粒子间等离子激元耦合效应，实现光热转换介导的肿瘤消融。通过光热转换的“阈值激活”策略，实现对肿瘤细胞的精准杀灭和对毗连正常组织的保护。. 3.制备了肿瘤酸响应型多肽自组装体，利用微酸性刺激下多肽自组装体形貌转变，增加肿瘤细胞对自组装体摄取，提高了光动力学治疗效果。. 4.将逻辑门策略多肽自组装体设计，构建肿瘤微酸性和基质金属蛋白酶正交刺激响应性多肽自组装体，实现药物肿瘤靶向运输与精准治疗。