微环境逐级响应性自组装靶向运输载体用于抑制肿瘤免疫逃逸的研究

肿瘤治疗中，基因疗法和免疫疗法都有巨大前景。目前免疫治疗的焦点是PD-1/PD-L1通路，该通路抑制T细胞增殖与活化，促使肿瘤免疫逃逸。通过基因调控阻断PD-1/PD-L1通路首先需要有效的载体。本研究采用氨基树枝状单元，以腙键和双硫键分别连接PEG和RGD肽，与葫芦[8]脲的主客体组装，获得微环境响应性基因载体NDCDP（NH2-Dendron⊂CB[8]⊃Dendron-PEG/PEPTIDE）。研究拟用NDCDP靶向运输siPD-L1，抑制肿瘤免疫逃逸。研究将对NDCDP的形态结构、响应性和靶向性进行验证；从体内外评价NDCDP/siPD-L1介导的PD-L1表达下调、T细胞激活、细胞因子分泌和疗效；进一步利用生物信息学技术对NDCDP/siPD-L1介导的细胞表达谱变化进行揭示，预测与免疫机制的关联。本研究不仅将基因与免疫治疗融合，更为载体介导下免疫治疗机制的探明奠定基础。

Gene therapy and immunotherapy have great potential in tumor therapy. At present, the PD-1/PD-L1 pathway, which inhibits the proliferation and activation of T cells, and promotes tumor immune escape, is a hotspot of immunotherapy. Effective gene vector is required while blocking the PD-1/PD-L1 pathway via RNA interference. In this study, dendrons modified by PEG and RGD peptide via hydrazone bond and disulfide bond are self-assembled with cucurbit[8]uril by host-guest interaction, forming a microenvironment-responsive gene vector, NDCDP (NH2-Dendron⊂CB[8]⊃Dendron-PEG/PEPTIDE). NDCDP with siPD-L1 will target the tumor cells and inhibit tumor immune escape. We will evaluate the structure, morphology, stimuli-responsive ability and tumor specificity of NDCDP system. We will also study the PD-L1 down-regulation, T cell activation, cytokine secretion and therapeutic effect mediated by NDCDP/siPD-L1 in vitro and in vivo. Furthermore, we will use systems biology approaches to uncover mechanisms underlying cellular responses to NDCDP/siPD-L1, and predict the association with immune system. This study will not only combine gene therapy and immunotherapy, but also lay the foundation for the study of mechanisms of vector mediated immunotherapy.