A Multistage Cooperative Nanoplatform Enables Intracellular Co-Delivery of Proteins and Chemotherapeutics for Cancer Therapy

Combining intracellularly active proteins with chemotherapeutics represents a promising strategy for synergistic cancer therapy. However, the lack of nanocarrier systems for delivery into cancer cells and controlled intracellular release of both physicochemically very distinct cargos significantly impedes the biomedical translation of this combination strategy in cancer therapy. Here, a well-designed triblock copolymer, mPEG-b-PGCA-b-PGTA, is reported for application in a multistage cooperative drug delivery nanoplatform that accomplishes effective intracellular co-delivery of hydrophilic ribonuclease A (RNase A) and hydrophobic doxorubicin (DOX). RNase A bioreversibly modified with phenylboronic acid groups via a ROS-cleavable carbamate linker is incorporated into the triblock copolymer nanoparticles with high efficiency through a pH-reversible phenylboronic acid-catechol linkage. The reversible covalent conjugations between RNase A and the triblock copolymer endow the nanoparticles with high stability under normal physiological conditions. Upon cellular internalization, the cooperative release of DOX and RNase A from the triblock copolymer nanoparticles is triggered at multiple stages by endosomal acidic environment and subsequent DOX-enhanced intracellular ROS environment. This leads to enhanced synergistic anticancer effects as demonstrated both in vitro and in vivo. Given the versatility of dynamic covalent conjugations, this work provides a universal and stable platform for intracellular co-delivery of various combinations of proteins and chemotherapeutics.

将细胞内有活性的蛋白质与化疗药物相结合是一种很有前景的癌症协同治疗策略。然而，缺乏能将两种物理化学性质差异很大的药物递送至癌细胞并控制其在细胞内释放的纳米载体系统，严重阻碍了这种联合策略在癌症治疗中的生物医学转化。在此，报道了一种精心设计的三嵌段共聚物，即甲氧基聚乙二醇 - 聚（γ - 谷氨酸 - 肉桂酸酯） - 聚（γ - 谷氨酸 - 对苯二甲酸酯）（mPEG - b - PGCA - b - PGTA），它可应用于一个多阶段协同药物递送纳米平台，实现亲水性核糖核酸酶A（RNase A）和疏水性阿霉素（DOX）在细胞内的有效共同递送。通过一种可被活性氧（ROS）切割的氨基甲酸酯连接体用苯硼酸基团对RNase A进行生物可逆修饰，然后利用pH可逆的苯硼酸 - 儿茶酚连接高效地将其掺入三嵌段共聚物纳米粒子中。RNase A与三嵌段共聚物之间的可逆共价结合使纳米粒子在正常生理条件下具有较高的稳定性。在细胞内化后，三嵌段共聚物纳米粒子中DOX和RNase A的协同释放由内涵体酸性环境以及随后由DOX增强的细胞内ROS环境在多个阶段触发。这导致了在体外和体内都得到证实的协同抗癌效果增强。鉴于动态共价结合的通用性，这项工作为蛋白质和化疗药物的各种组合在细胞内的共同递送提供了一个通用且稳定的平台。