已提出一种针对转移性乳腺癌的靶向协同联合治疗的双层方法。首先，通过碳酰二亚胺（CDI）偶联化学反应，使用桦皮酸-二硫化物-d-α-生育酚聚（乙二醇）琥珀酸酯（BA-Cys-T）制备了紫杉醇（PX）负载的氧化还原敏感自组装胶束系统。其次，通过半胱氨酸间距在TPGS上化学地锚定了透明质酸（HA-Cys-T），实现CD44受体介导的靶向作用。 我们已经确定，PX和BA在摩尔比为1：5时具有显著的协同作用，组合指数为0.27。综合系统包括BA-Cys-T和HA-Cys-T（PX/BA-Cys-T-HA），其摄入量比PX/BA-Cys-T高得多，表明有优先的CD44介导的摄入，且能够在高谷胱甘肽浓度的刺激下快速释放药物。PX/BA-Cys-T-HA的细胞凋亡率为42.89%，明显高于BA-Cys-T（12.78%）和PX/BA-Cys-T（33.38%）。此外，当在MDA-MB-231细胞系中测试时，PX/BA-Cys-T-HA表现出显著提高的细胞周期阻滞、改善的线粒体膜电位去极化以及诱导过多产生的ROS。定向微粒的体内给药显示出改善的药代动力学参数和对4T1诱导的肿瘤负荷BALB/c小鼠的显著肿瘤生长抑制作用。 总体而言，该研究表明PX/BA-Cys-T-HA在实现对转移性乳腺癌的时间和空间靶向治疗方面具有潜在作用。

A two-tier approach has been proposed for targeted and synergistic combination therapy against metastatic breast cancer. First, it comprises the development of a paclitaxel (PX)-loaded redox-sensitive self-assembled micellar system using betulinic acid-disulfide-d-α-tocopheryl poly(ethylene glycol) succinate (BA-Cys-T) through carbonyl diimidazole (CDI) coupling chemistry. Second, hyaluronic acid is anchored to TPGS (HA-Cys-T) chemically through a cystamine spacer to achieve CD44 receptor-mediated targeting. We have established that there is significant synergy between PX and BA with a combination index of 0.27 at a molar ratio of 1:5. An integrated system comprising both BA-Cys-T and HA-Cys-T (PX/BA-Cys-T-HA) exhibited significantly higher uptake than PX/BA-Cys-T, indicating preferential CD44-mediated uptake along with the rapid release of drugs in response to higher glutathione concentrations. Significantly higher apoptosis (42.89%) was observed with PX/BA-Cys-T-HA than those with BA-Cys-T (12.78%) and PX/BA-Cys-T (33.38%). In addition, PX/BA-Cys-T-HA showed remarkable enhancement in the cell cycle arrest, improved depolarization of the mitochondrial membrane potential, and induced excessive generation of ROS when tested in the MDA-MB-231 cell line. An in vivo administration of targeted micelles showed improved pharmacokinetic parameters and significant tumor growth inhibition in 4T1-induced tumor-bearing BALB/c mice. Overall, the study indicates a potential role of PX/BA-Cys-T-HA in achieving both temporal and spatial targeting against metastatic breast cancer.