基于PLL构建刺激响应性递送siRNA载体抗Her2阳性乳腺癌治疗研究

Gene therapy is greatly limited in clinical application due to the lack of safe and effective gene delivery system. Herein, we construct a gene delivery system based on reversibly cross-linked [(PLL-LA)/siRNA-EGFR/(PLL-Cit/Her2 antibody) ternary polyplex nanoparticles with pH and reduction dual-sensitivity, and using siRNA-EGFR as therapy gene. In vitro, the gene transfection efficiency, gene silencing efficiency and the cytotoxicity of the nanoparticles on BT474 human breast cancer cells will be explored. In vivo, the targeting property of nanoparticles in the mice-bearing BT474 breast cancer is evaluated using in vivo fluorescence imaging instrument, and the therapeutic efficiency nanoparticles for the mice-bearing BT474 breast cancer is also accordingly researched. The research of this project will provide new technology and method for treating breast cancer overexpressing Her2.

高效无毒的基因递送载体的缺乏，限制了基因治疗的临床应用。申请者在本人硕士论文工作基础上,合成PLL-LA以及Her2抗体修饰的PLL-Cit两种聚合物载体,以EGFR-siRNA治疗基因，构建具有pH和还原双重响应的可逆交联的三层结构的纳米粒[(PLL-LA)/EGFR-siRNA/(PLL-Cit/Her2 antibody)].体外实验评价纳米粒对Her2阳性表达的BT474人乳腺癌细胞的靶向性、基因转染效率、基因沉默效率及其细胞毒性的影响，并探讨影响的机制。利用活体荧光成像仪实时观察载基因纳米粒在荷BT474人乳腺癌裸鼠体内的靶向特性；研究载基因纳米粒对荷BT474人乳腺癌裸鼠治疗效率。本项目的研究将为治疗Her2阳性乳腺癌提供新的技术和方法。

Her2阳性乳腺癌恶性程度更高、转移更快、更易复发，而EGFR是Her2阳性乳腺癌的一个有效靶标，因此对靶向Her2阳性乳腺癌基因治疗的研究具有非常重要的科学价值。本项目以siRNA-EGFR为治疗分子，构建了具有pH和还原双重响应的可逆交联的靶向基因递送系统[(PLL-LA)/EGFR-siRNA/(PLL-Cit/Her2 antibody)]。通过实验验证可知，我们构建的双重响应的纳米粒可以显著沉默BT474人乳腺癌细胞中EGFR蛋白的表达，同时该纳米粒在体内具有明显的抑瘤作用：具有肿瘤靶向性，且可以显著抑制荷BT474人乳腺癌裸鼠的肿瘤生长。本研究为载siRNA-EGFR纳米递送系统对Her2阳性乳腺癌的治疗的临床应用提供了新的技术和方法。