三阴性乳腺癌（TNBC）预后差，临床急需治疗方案。申请者前期研究发现将EGFR抑制剂靶向递送后抑瘤效果显著，可见靶向EGFR的小干扰RNA（siRNA）对TNBC治疗具有潜力，但仍需克服单靶疗效有限、载体封装后胞内释放效率低等缺陷。本项目将“联合给药”和“多级响应”相结合，构建一种“双pH/氧化还原”级联触发的共载基因药物载体。首次将双硒键与DMAEMA单体交联制备新型材料，并以EGFR和BRD4为靶点，将两种siRNA包载于修饰有“程序式脱落”的 CREKA和GALA肽的纳米粒中。CREKA肽实现肿瘤靶向，微酸环境裂解腙键促使PEG层脱落以便入胞，并暴露出掩盖的GALA肽；入胞后溶酶体中GALA肽恢复α-螺旋，其膜致孔效应加速纳米粒逃逸；最后胞质中高浓度的谷胱甘肽诱导载体材料中双硒键断裂，实现药物快速释放。本项目既是双靶点联合用药治疗TNBC的有益探索，又为体内递送基因药物提供了新思路。

Triple-negative breast cancer (TNBC) has the poorest prognosis, and is badly in need of therapeutic regimen. In our previous studies, the epidermal growth factor receptor (EGFR) inhibitor was specifically delivered to tumor and exhibited significant superiority on anti-tumor effects, indicating that small inference RNA (siRNA) targeting to the EGFR has shown great potential for the treatment of TNBC. However, aiming at one target with limited effects and low efficiency of intracelluar release both hinder the application of siRNA. To overcome these obstacles, “combination therapy” and “sequential response” are applied together in this project to construct a novel gene carrier, which could be triggered by “dual pH/Redox”. Diselenium(Se-Se)-containing and PEG-modified poly (2-(N,N-dimethylamino) ethyl methacrylate) (PEG- hydrazone-PDMAEMA), was chosen to be the cationic polymer in this study. Then for combination therapy, siRNA drugs targeting EGFR and BRD4, are encapsulated into nanoparticles modified with CREKA and pH-sensitive GALA. CREKA peptide helps nanoparticles for tumor targeting. Then cell-penetrating peptide GALA, which was originally protected by PEG, are exposed after the hydrazone broken in acidic environment around tumors to enhance the lysosomal escape of nanoparticles. Finally, the fast release of siRNA is mediated by the diselenium broken, which was induced by the high intracellular concentration of reduced glutathione (GSH). This project would be not only a beneficial exploration in the combination therapy of siRNA for TNBC, but also an new idea for delivering gene drugs in vivo.