靶向及pH敏感仿脂蛋白结构纳米载体运载紫杉醇的抗肿瘤研究

Anti-Tumor Activity of Tumor-Targeting pH-Sensitive Lipoprotein-Mimic Nanocarrier Loaded with Paclitaxel

目的本实验制备一种具有靶向及pH敏感功能的新型仿脂蛋白结构纳米载体(BSA-LC/DOPE),包载紫杉醇(paclitaxel,PTX)用于肿瘤的有效治疗。方法利用透析法考察纳米载体的体外pH敏感释药行为;通过纳米载体在血浆中的凝聚变化对其血浆稳定性进行考察;采用四甲基偶氮唑蓝(MTT)法对载药制剂进行细胞毒性研究;利用激光扫描共聚焦显微镜观测仿脂蛋白结构纳米载体的细胞内化情况及BSA-LC/DOPE在亚细胞器定位情况及细胞内药物释放行为。结果纳米载体在体外不同pH条件下具有敏感的pH释放药物行为;在血浆孵育后的粒径分布没有明显变化,表明其在血浆中具有良好的稳定性;具有BSA靶向分子的BSA-LC/DOPE-PTX与无靶向分子的LC/DOPE-PTX相比,对MCF-7肿瘤细胞具有最强的细胞生长抑制作用;BSA-LC/DOPE在溶酶体的酸性环境下pH敏感释放药物,并从溶酶体中逃逸至细胞质和细胞核中,具有显著的溶酶体逃逸功能。结论 BSA-LC/DOPE作为具有生物相容性,肿瘤靶向以及pH敏感释药功能的一种新型脂蛋白结构纳米载体,有效将药物紫杉醇递送至肿瘤细胞内,达到理想的抗肿瘤效果。

OBJECTIVE To construct a tumor-targeting and pH-sensitive lipoprotein-mimic nanocarrier containing paclitaxel （BSA-LC/DOPE-PTX） for effective antitumor therapy. METHODS In vitro drug release study was conducted using dialysis method. The stability of BSA-LC/DOPE-PTX was studied by testing the aggregation of BSA-LC/DOPE-PTX in 50% human plasma. The eyto- toxicity of drug-loaded nanocarrier against MCF-7 cells was evaluated by standard MTT assay. The subeellular localization and intracel- lular drug release behavior of BSA-LC/DOPE were evaluated by LSCM. RESULTS In vitro drug release study demonstrated that pa- clitaxel（PTX） was released from BSA-LC/DOPE in a pH-dependent manner. The stability study showed that there was no significant change, suggesting that the coupling BSA could increase the stability in plasma. The cellular inhibition of BSA-LC/DOPE-PTX with BSA targeting agents was greater than that of LC/DOPE-PTX. BSA-LC/DOPE facilitated the capacity of endosomal escape, and rapidly released the loaded agents into the cytoplasm under acid conditions in lysosomes. CONCLUSION BSA-LC/DOPE, as biocompati- ble, tumor-targeting and pH-sensitive lipoprotein-mimie nanocarrier, is a promising system for effective intracellular delivery of PTX to tumors with optimal anti-tumor efficacy.