Yang Xiaoye, Cai Xiaoqing, Yu Aihua, Xi Yanwei, Zhai Guangxi
Department of Pharmaceutics, College of Pharmacy, Shandong University, Jinan 250012, China.
Department of Pharmaceutics, College of Pharmacy, Shandong University, Jinan 250012, China.
J Colloid Interface Sci. 2017 Jun 15;496:311-326. doi: 10.1016/j.jcis.2017.02.033. Epub 2017 Feb 16.
To remedy the problems riddled in cancer chemotherapy, such as poor solubility, low selectivity, and insufficient intra-cellular release of drugs, novel heparin-based redox-sensitive polymeric nanoparticles were developed. The amphiphilic polymer, heparin-alpha-tocopherol succinate (Hep-cys-TOS) was synthesized by grafting hydrophobic TOS to heparin using cystamine as the redox-sensitive linker, which could self-assemble into nanoparticles in phosphate buffer saline (PBS) with low critical aggregation concentration (CAC) values ranging from 0.026 to 0.093mg/mL. Paclitaxel (PTX)-loaded Hep-cys-TOS nanoparticles were prepared via a dialysis method, exhibiting a high drug-loading efficiency of 18.99%. Physicochemical properties of the optimized formulation were characterized by dynamic light scattering (DLS), transmission electron microscope (TEM) and differential scanning calorimetry (DSC). Subsequently, the redox-sensitivity of Hep-cys-TOS nanoparticles was confirmed by the changes in size distribution, morphology and appearance after dithiothreitol (DTT) treatment. Besides, the in vitro release of PTX from Hep-cys-TOS nanoparticles also exhibited a redox-triggered profile. Also, the uptake behavior and pathways of coumarin 6-loaded Hep-cys-TOS nanoparticles were investigated, suggesting the nanoparticles could be taken into MCF-7 cells in energy-dependent, caveolae-mediated and cholesterol-dependent endocytosis manners. Later, MTT assays of different PTX-free and PTX-loaded formulations revealed the desirable safety of PTX-free nanoparticles and the enhanced anti-cancer activity of PTX-loaded Hep-cys-TOS nanoparticles (IC=0.79μg/mL). Apoptosis study indicated the redox-sensitive formulation could induce more apoptosis of MCF-7 cells than insensitive one (55.2% vs. 41.7%), showing the importance of intracellular burst release of PTX. Subsequently, the hemolytic toxicity confirmed the safety of the nanoparticles for intravenous administration. The results indicated the developed redox-sensitive nanoparticles were promising as intracellular drug delivery vehicles for cancer treatment.
为了解决癌症化疗中存在的问题，如溶解性差、选择性低和药物细胞内释放不足等，人们开发了新型的基于肝素的氧化还原敏感型聚合物纳米颗粒。两亲性聚合物肝素-α-生育酚琥珀酸酯（Hep-cys-TOS）通过使用胱胺作为氧化还原敏感连接子将疏水性的生育酚琥珀酸酯（TOS）接枝到肝素上合成，其在磷酸盐缓冲盐水（PBS）中能够自组装成纳米颗粒，临界聚集浓度（CAC）值较低，范围为0.026至0.093mg/mL。通过透析法制备了负载紫杉醇（PTX）的Hep-cys-TOS纳米颗粒，其药物负载效率高达18.99%。通过动态光散射（DLS）、透射电子显微镜（TEM）和差示扫描量热法（DSC）对优化后的制剂的物理化学性质进行了表征。随后，通过二硫苏糖醇（DTT）处理后纳米颗粒的尺寸分布、形态和外观变化证实了Hep-cys-TOS纳米颗粒的氧化还原敏感性。此外，PTX从Hep-cys-TOS纳米颗粒中的体外释放也呈现出氧化还原触发的特征。同时，研究了负载香豆素6的Hep-cys-TOS纳米颗粒的摄取行为和途径，表明纳米颗粒可以通过能量依赖、小窝介导和胆固醇依赖的内吞方式进入MCF-7细胞。随后，对不同的无PTX和负载PTX的制剂进行MTT分析，结果显示无PTX纳米颗粒具有良好的安全性，而负载PTX的Hep-cys-TOS纳米颗粒具有增强的抗癌活性（IC=0.79μg/mL）。凋亡研究表明，氧化还原敏感型制剂比不敏感型制剂能诱导更多的MCF-7细胞凋亡（55.2%对41.7%），这表明PTX细胞内爆发释放的重要性。随后，溶血毒性证实了纳米颗粒用于静脉给药的安全性。结果表明，所开发的氧化还原敏感型纳米颗粒有望作为癌症治疗的细胞内药物递送载体。
