Tumor-derived extracellular vesicle (EV) microRNAs (miRNAs) are important biomarkers for clinical diagnosis and disease treatment monitoring. However, the need to lyse EVs makes most methods for detection of tumor-derived EV miRNA expensive, labour-intensive, and time-consuming. Inspired by natural vesicular transport, we here developed a general strategy for in situ detection of tumor-derived EV miRNAs using aptamer-mediated selective fusion (Apt-Fusion). Taking advantages of the high selectivity, rapid and general applicability of Apt-Fusion, this method exhibits significant sensitivity and selectivity for tumor-derived EV miRNAs in a lysis-free manner using conventional flow cytometry. Using this method, the level of miR-21 in PD-L1 positive EVs was quantified and found to effectively distinguish cancer patients from healthy volunteers; additionally, miR-21 in PD-L1 positive EVs was found for the first time to correlate with tumor burden. Overall, Apt-Fusion holds great potential to detect tumor-derived EV miRNAs and expand detection of EV multi-molecular compositions, offering a new avenue for cancer diagnosis and immunotherapy response monitoring.

肿瘤来源的细胞外囊泡 (EV) microRNA (miRNA) 是临床诊断和疾病治疗监测的重要生物标志物。然而，裂解 EV 的需要使得大多数检测肿瘤衍生的 EV miRNA 的方法昂贵、劳动密集且耗时。受自然囊泡运输的启发，我们在这里制定了原位的总体策略使用适体介导的选择性融合 (Apt-Fusion) 检测肿瘤衍生的 EV miRNA。该方法利用 Apt-Fusion 的高选择性、快速和普遍适用性的优势，使用常规流式细胞仪以无裂解的方式对肿瘤衍生的 EV miRNA 表现出显着的灵敏度和选择性。使用这种方法，对 PD-L1 阳性 EV 中 miR-21 的水平进行了量化，发现可以有效区分癌症患者和健康志愿者；此外，首次发现 PD-L1 阳性 EV 中的 miR-21 与肿瘤负荷相关。总体而言，Apt-Fusion 在检测肿瘤来源的 EV miRNA 和扩大 EV 多分子成分的检测方面具有巨大潜力，为癌症诊断和免疫治疗反应监测提供了新途径。