以肿瘤细胞特异性酶为靶点的自组装载药系统活体在线分析

Targeting drugs delivery system (TDDS) has been the most advanced preparation for tumor clinical therapy. The detection and evaluation of the drug transfer performance about the TDDS is also a scientific problem that pharmaceutical analysis needs to solve. At present, the drug transport characteristics evaluation of the TDDS is indirect, primarily through the detection of drug molecules in the animal tissue in vitro. Therefore, a non-invasive and direct analytical method in vivo is needed, which is capable to detect TDDS behavior in vivo and evaluate its transfer efficiency. At the earlier stage, the research team successfully carried out the TDDS tracer analysis in tumor cell by entrapping the fluorescence agent into drug delivery system. In this study, firstly, the tumor cell specific enzyme-histone acetylation enzyme is used as the target and the specific directing groups will be designed. Second, fluorescent probe is covalently connected to biocompatible polymer materials and the tracing and active targeting self-assembled drug delivery system will be constructed. Finally, using the in vivo fluorescence molecular imaging technology, the TDDS analysis method in vivo will be established after a methodological study, which can continuously and dynamically monitor the behavior of the TDDS in the tumor cell and living animal. This method not only combines the advantages of "targeting drug delivery - behavior tracer" in one whole, but also on the whole shows the in vivo drug distribution process under the complete physiological state. In a follow-up research work, the emphasis is to confirm the feasibility of the design ideas and carry out the relevant basic research, and to clarify the in vivo behavior and mechanism of the TDDS. Through these studies, a theory basis will be provided for establishing an in vivo analysis method of the TDDS.

靶向载药系统(TDDS)是当今癌症治疗最具先进性的用药形式，对TDDS药物传输性能的检测与评价也是药物分析学需要解决的科学问题。目前对TDDS的研究主要通过检测离体动物组织中的药物分子，间接评价药物转运特征，因此，有必要建立一种非侵入性、直接的在体分析方法。课题组前期以荧光素包载法成功开展了TDDS在肿瘤细胞的示踪分析。在此基础上，本课题选择肿瘤细胞特异性组蛋白去乙酰化酶为靶点，设计导向基团，以荧光探针共价连接生物相容材料，构建能够示踪的主动靶向自组装载药系统；利用活体荧光分子成像技术，连续动态监测TDDS在肿瘤细胞和动物体内的行为，结合体内分析方法学研究，建立TDDS的活体在线分析。该方法集"靶向给药-行为示踪"于一体，更从整体上展示了完整生理状态下TDDS的在体分布情况。课题重点验证设计思路的可行性，进行相关基础研究，阐明TDDS的体内过程和作用规律，为活体在线分析方法提供理论基础。

随着纳米技术和靶向载药系统的迅速发展和快速应用，评价载药系统在体内的过程和药物输送的有效性，成为药物分析学需要解决的一个科学问题。本项目旨在以肿瘤细胞特异性酶——组蛋白去乙酰化酶（HDACs）为靶点，构建主动靶向自组装载药系统；利用活体荧光分子成像技术，建立一种非侵入性、实时在体分析方法，连续动态监测载药系统在完整生理状态下的体内过程，既了解载药系统的体内行为，又获知载药系统的靶向效率。为此，课题完成了以下四部分研究工作：.（1）根据已上市HDACs抑制剂的药效团模型，设计了两个系列的化合物作为靶向基团，共合成54个未见国内外报道的新型化合物；体外活性评价结果表明，所合成化合物能够与HDACs相结合，并表现出抑制活性. .（2）以设计、合成的化合物为对象，利用SYBYL工作站模拟HDACs与化合物分子的相互作用，解析了相互作用的位点及作用模式；选择与HDACs作用活性强、对接模型作用力强的化合物FA17，作为导向基团，合成靶向生物相容性材料；并以此材料构建了靶向纳米粒，使纳米粒具有定位肿瘤细胞HDACs的功能。.（3）以HDACs高表达的乳腺癌细胞MCF-7为模型，采用荧光成像分析系统连续监测了MCF-7细胞对靶向纳米粒的优先摄取和延时滞留过程，并通过荧光定量分析方法进一步确证靶向纳米粒摄入和滞留细胞内的量明显高于未经HDACs导向基团修饰的纳米粒。.（4）动物体内可见光成像系统，实时跟踪了靶向纳米粒在MCF-7移植瘤小鼠体内对肿瘤组织分布的趋向性和正常组织分布的选择性，并通过肿瘤抑制试验和抗肿瘤药物在动物组织蓄积的定量分析，从整体水平证实纳米粒的体内靶向效率。. 通过项目研究实现了以肿瘤细胞过度表达的特异性酶为靶标，构建了具有示踪功能的主动靶向自组装载药系统；可从细胞和整体水平非侵入性、连续动态监测载药系统的行为。项目的完成不仅为纳米载药系统细胞和整体水平的药物传输性能评价提供了方法，也为载药系统的实时过程分析提供了思路。.