State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Biomedical Materials and Engineering Research Center of Hubei Province, Wuhan University of Technology, Wuhan 430070, China.
Biomacromolecules. 2023 May 8;24(5):2225-2236. doi: 10.1021/acs.biomac.3c00134. Epub 2023 Apr 11.
The design of nano-drug delivery vehicles responsive to tumor microenvironment stimuli has become a crucial aspect in developing cancer therapy in recent years. Among them, the enzyme-responsive nano-drug delivery system is particularly effective, as it utilizes tumor-specific and highly expressed enzymes as precise targets, leading to increased drug release at the target sites, reduced nonspecific release, and improved efficacy while minimizing toxic side effects on normal tissues. NAD(P)H:quinone oxidoreductase 1 (NQO1) is an important reductase associated with cancer and is overexpressed in some cancer cells, particularly in lung and breast cancer. Thus, the design of nanocarriers with high selectivity and responsiveness to NQO1 is of great significance for tumor diagnosis and treatment. It has been reported that under physiological conditions, NQO1 can specifically reduce the trimethyl-locked benzoquinone structure through a two-electron reduction, resulting in rapid lactonization via an enzymatic reaction. Based on this, a novel reduction-sensitive polyurethane (PEG-PTU-PEG) block copolymer was designed and synthesized by copolymerizing diisocyanate, a reduction-sensitive monomer (TMBQ), and poly(ethylene glycol). The successful synthesis of monomers and polymers was verified by nuclear magnetic resonance (H NMR) and gel permeation chromatography (GPC). Then, the PEG-PTU-PEG micelles were successfully prepared by self-assembly, and their reductive dissociation behavior in the presence of NaSO was verified by dynamic light scattering (DLS), H NMR, and GPC. Next, the model drug doxorubicin (DOX) was encapsulated into the hydrophobic core of this polyurethane micelles by microemulsion method. It was observed that the drug-loaded micelles could also achieve a redox response and rapidly release the encapsulated substances. cell experiments demonstrated that PEG-PTU-PEG micelles had good biocompatibility and a low hemolysis rate (<5%). Furthermore, in the presence of an NQO1 enzyme inhibitor (dicoumarol), lower drug release from micelles was observed in A549 and 4T1 cells by both fluorescence microscopy and flow cytometry assays, but not in NIH-3T3 control cells. Predictably, DOX-loaded micelles also showed lower cytotoxicity in 4T1 cells in the presence of NQO1 enzyme inhibitors. These results indicate that drug-loaded polyurethane micelles could accomplish specific drug release in the reducing environment in the presence of NQO1 enzymes. Therefore, this study provides a new option for the construction of polyurethane nanocarriers for precise targeting and reductive release, which could benefit the intracellular drug-specific release and precision therapy of tumors.
纳米药物递送载体对肿瘤微环境刺激的响应设计已成为近年来癌症治疗的一个关键方面。其中，酶响应型纳米药物递送系统尤为有效，因为它利用肿瘤特异性和高表达的酶作为精确靶点，导致在靶部位增加药物释放，减少非特异性释放，并提高疗效，同时最大限度地减少对正常组织的毒性副作用。烟酰胺腺嘌呤二核苷酸（磷酸）：醌氧化还原酶 1（NQO1）是一种与癌症相关的重要还原酶，在一些癌细胞中过度表达，特别是在肺癌和乳腺癌中。因此，设计对 NQO1 具有高选择性和响应性的纳米载体对于肿瘤的诊断和治疗具有重要意义。据报道，在生理条件下，NQO1 可以通过双电子还原特异性地还原三甲基锁定苯醌结构，通过酶反应迅速发生内酯化。基于此，通过共聚二异氰酸酯、还原敏感单体（TMBQ）和聚（乙二醇），设计并合成了一种新型的还原敏感型聚氨酯（PEG-PTU-PEG）嵌段共聚物。通过核磁共振（H NMR）和凝胶渗透色谱（GPC）验证了单体和聚合物的成功合成。然后，通过自组装成功制备了 PEG-PTU-PEG 胶束，并通过动态光散射（DLS）、H NMR 和 GPC 验证了其在 NaSO 存在下的还原解离行为。接下来，通过微乳液法将模型药物阿霉素（DOX）包封到该聚氨酯胶束的疏水性核中。观察到载药胶束也可以实现氧化还原响应，并迅速释放包封的物质。细胞实验表明，PEG-PTU-PEG 胶束具有良好的生物相容性和较低的溶血率（<5%）。此外，在 NQO1 酶抑制剂（双香豆素）存在下，通过荧光显微镜和流式细胞术检测，在 A549 和 4T1 细胞中观察到载药胶束的药物释放减少，但在 NIH-3T3 对照细胞中未观察到。可以预测，在 NQO1 酶抑制剂存在下，载 DOX 胶束对 4T1 细胞的细胞毒性也较低。这些结果表明，负载药物的聚氨酯胶束可以在 NQO1 酶存在下的还原环境中实现特定药物释放。因此，本研究为构建用于精确靶向和还原释放的聚氨酯纳米载体提供了一种新的选择，这可能有利于肿瘤细胞内药物的特异性释放和精准治疗。
