肿瘤细胞靶向和内涵体逃逸的纳米给药系统用于多靶点肿瘤治疗

According to the mechanism of multi-target therapy, siRNA and cytotoxic drug were selected simultaneously for cancer therapy. A nano-sized drug delivery system with tumor cell-specific targeting and rapid endosomal escape has been constructed through resonable design and the modification of tumor homing peptide and fusogenic peptide. The system will be applied in tumor targeting therapy in order to achieve synergistic effect of multi-target therapy through using different siRNA and cytotoxic drug..The characteristics of the project: The project has strong novelty. First, cytotoxic drug (doxorubicin) can direct damage to tumor cells. Moreover, siRNA targeted against VEGFR-2 can inhibit the growth of tumor angiogenic vessel and siRNA targeted against PLK1 can inhibit mitosis of tumor cells. Whereafter they affect the tumor signal transduction pathway to kill tumor cells. The strategy can effectively solve the problem that single drug usually doesn't have good antitumor efficacy due to various reasons in the treatment. Liposomes as the siRNA and DOX vehicles used for tumor targeting can improve the stability of siRNA and play improving roles of the EPR effect. The modification of tumor homing peptide (SP94) that can specifically bind to hepatocellular carcinoma and a histidine-rich fusogenic peptide (H5WYG) that can promote endosomal escape, can play effectively gene silence and kill the tumor cell by the synergy of siRNA and DOX. The study can provide references for tumor multi-target therapy and personalized therapy through the determination of biomarkers in tumor and on signal transduction pathway..The study has interdisciplinary feature. The multi-target therapy is a novel and effective strategy for cancer therapy. Therefore, it is significant to do some work on multi-targeting therapy by nano-vehicles delivery.

根据多靶点治疗的机理，选择作用于不同靶点的siRNA和细胞毒药物，使用对肿瘤细胞有高特异亲和性的多肽，辅以膜融合肽等，构建高肿瘤靶向性和快速内涵体逃逸的纳米载药系统应用于肿瘤的靶向治疗，以实现不同siRNA与细胞毒药物的多靶点治疗的协同作用。本项目的特点：细胞毒药物对肿瘤细胞的直接杀伤作用，VEGFR-2为靶点的siRNA抑制肿瘤新生血管的生成，PLK1为靶点的siRNA抑制肿瘤细胞有丝分裂，进而影响肿瘤的信号传导通路，实现对肿瘤的治疗作用，优于单一药物的治疗；脂质体作为药物的纳米载体，siRNA和多柔比星高载量包封于脂质体中，肿瘤细胞特异的靶向肽SP94和富含组氨酸的融合肽H5WYG的双重修饰，使脂质体具有肿瘤细胞靶向和内涵体逃逸功能，有效地发挥siRNA和药物的治疗作用；通过对靶点和信号通路中肿瘤标志物的检测及作用机理的研究，为肿瘤的多靶点治疗和个体化治疗提供依据。

本课题根据多靶点治疗的机理，选择作用于不同靶点的siRNA 和细胞毒药物，使用对肿瘤细胞有高特异亲和性的多肽，辅以膜融合肽等，构建高肿瘤靶向性和快速内涵体逃逸的纳米载药系统，以实现siRNA与细胞毒药物的多靶点协同治疗。.以siRNA和多西他赛为模型药物，构建了SP94/H5WYG双肽修饰的脂质体和Angiopep-2/tLyP-1双肽修饰的阳离子脂质体，分别用于肝癌和脑胶质瘤的研究。靶向肽SP94的修饰有利于药物在肝肿瘤细胞蓄积，融合肽H5WYG的修饰促进脂质体在溶酶体中的释放，防止siRNA被破坏；由Angiopep-2/tLyP-1双肽修饰的脂质体对肿瘤组织穿透能力强，提高肿瘤组织和细胞中药物的蓄积，促进了VEGF沉默的抗血管生成和细胞凋亡诱导，提高了抗胶质瘤治疗效果。.针对转移性肿瘤，本课题构建了tLPTS/HATS混合纳米粒，通过CD44和NRP-1/2双受体介导的内吞作用提高转移性肿瘤细胞内的靶向递送效率，对原位肿瘤和肿瘤转移灶均具有良好的靶向性，能显著抑制原位肿瘤和肿瘤转移灶的生长。.针对耐药性肿瘤，本课题构建了TPGS修饰的HATS/TPGS抗耐药混合纳米粒。该纳米粒能抑制P-gp蛋白对其底物的外排作用，提高耐药性肿瘤细胞的胞内药物浓度，从而克服肿瘤耐药；诱导肿瘤细胞凋亡，克服肿瘤内源性耐药，提高抗肿瘤耐药的治疗效果。.根据肿瘤微环境低pH的特点，本课题构建了酸敏感型纳米粒，共递送阿霉素（DOX）和小干扰RNA（siRNA）。该多功能纳米靶向复合物将化疗药物与基因药物共递送到肿瘤组织中，利用肿瘤微环境低pH值定点释放药物，提高抗肿瘤效果。.综上，本课题采用化疗药物和基因药物联用的多靶点治疗策略，降低化疗药物毒副作用，提高药物的治疗效果。在研究中，应用多西他赛、阿霉素等化学药物与基因药物siRNA联合应用，在体外及体内都证明药物作用于不同的靶点有协同或加和的抗肿瘤效果，为肿瘤靶向治疗研究领域拓宽了研究思路。.