核苷类似物是癌症治疗的有效抑制剂，但其在人类中应用的主要障碍是其毒性、非特异性和缺乏靶向递送工具。在这里，我们报告了使用 RNA 四路连接 (4WJ) 来传递两种核苷类似物：氟尿苷 (FUDR) 和吉西他滨 (GEM)，通过常规和简单的固态 RNA 合成和纳米颗粒组装，具有高有效负载。用于核苷类似物和化疗药物紫杉醇（PTX）共同递送的RNA纳米技术的设计在三阴性乳腺癌（TNBC）的治疗中产生了协同效应和高效能。 4WJ-药物复合物被证实具有有效的肿瘤自发靶向性且无毒性，因为先前已证明RNA纳米颗粒的运动性使这些RNA-药物复合物能够在肿瘤血管中自发积累。 RNA的负电荷使得那些不针对肿瘤脉管系统的RNA复合物能够在血液中循环并通过肾小球进入尿液，而不会在器官中积聚，因此是无毒的。药物掺入 RNA 4WJ 可以通过确定的装载量、位置和比率进行精确控制。将核苷类似物掺入 4WJ 仅需要在固相 RNA 合成过程中使用核苷类似物亚磷酰胺一步，无需额外的缀合和纯化过程。

Nucleoside analogs are potent inhibitors for cancer treatment, but the main obstacles to their application in humans are their toxicity, nonspecificity, and lack of targeted delivery tools. Here, we report the use of RNA four-way junctions (4WJs) to deliver two nucleoside analogs, floxuridine (FUDR) and gemcitabine (GEM), with high payloads through routine and simple solid-state RNA synthesis and nanoparticle assembly. The design of RNA nanotechnology for the co-delivery of nucleoside analogs and the chemotherapeutic drug paclitaxel (PTX) resulted in synergistic effects and high efficacy in the treatment of Triple-Negative Breast Cancer (TNBC). The 4WJ-drug complexes were confirmed to have efficient tumor spontaneous targeting and no toxicity because the motility of RNA nanoparticles has been previously shown to enable these RNA-drug complexes to spontaneously accumulate in tumor blood vessels. The negative charge of RNA enables those RNA complexes that are not targeted to tumor vasculature to circulate in the blood and enter the urine through the kidney glomerulus, without accumulating in organs, therefore being nontoxic. Drug incorporation into RNA 4WJ can be precisely controlled with a defined loading amount, location, and ratio. The incorporation of nucleoside analogs into 4WJ only requires one step using nucleoside analogue phosphoramidites during solid-phase RNA synthesis, without the need for additional conjugation and purification processes.