State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan 430079, China.
Department of Oral and Maxillofacial Surgery, School and Hospital of Stomatology, Wuhan University, Wuhan 430079, China.
Anal Chem. 2024 Sep 17;96(37):14980-14988. doi: 10.1021/acs.analchem.4c03101. Epub 2024 Sep 5.
PD-L1-positive extracellular vesicles (PD-L1 EVs) play a pivotal role as predictive biomarkers in cancer immunotherapy. These vesicles, originating from immune cells (I-PD-L1 EVs) and tumor cells (T-PD-L1 EVs), hold distinct clinical predictive values, emphasizing the importance of deeply differentiating the PD-L1 EV subtypes for effective liquid biopsy analyses. However, current methods such as ELISA lack the ability to differentiate their cellular sources. In this study, a novel step-wedge microfluidic chip that combines magnetic microsphere separation with single-layer fluorescence counting is developed. This chip integrates magnetic microspheres modified with anti-PD-L1 antibodies and fluorescent nanoparticles targeting EpCAM (tumor cell marker) or CD45 (immunocyte marker), enabling simultaneous quantification and sensitive analysis of PD-L1 EV subpopulations in oral squamous cell carcinoma (OSCC) patients' saliva without background interference. Analysis results indicate reduced levels of I-PD-L1 EVs in OSCC patients compared to those in healthy individuals, with varying levels of heterogeneous PD-L1 EVs observed among different patient groups. During immunotherapy, responders exhibit decreased levels of total PD-L1 EVs and T-PD-L1 EVs, accompanied by reduced levels of I-PD-L1 EVs. Conversely, nonresponders show increased levels of I-PD-L1 EVs. Utilizing the step-wedge microfluidic chip allows for simultaneous detection of PD-L1 EV subtypes, facilitating the precise prediction of oral cancer immunotherapy outcomes.
PD-L1 阳性细胞外囊泡（PD-L1 EVs）在癌症免疫治疗中作为预测生物标志物发挥着关键作用。这些囊泡源自免疫细胞（I-PD-L1 EVs）和肿瘤细胞（T-PD-L1 EVs），具有不同的临床预测价值，强调了深入区分 PD-L1 EV 亚型以进行有效的液体活检分析的重要性。然而，目前的方法，如 ELISA，缺乏区分其细胞来源的能力。在这项研究中，开发了一种新型楔形微流控芯片，该芯片结合了磁性微球分离和单层荧光计数。该芯片集成了用抗 PD-L1 抗体修饰的磁性微球和靶向 EpCAM（肿瘤细胞标志物）或 CD45（免疫细胞标志物）的荧光纳米颗粒，能够在没有背景干扰的情况下，同时定量和敏感地分析口腔鳞状细胞癌（OSCC）患者唾液中的 PD-L1 EV 亚群。分析结果表明，与健康个体相比，OSCC 患者的 I-PD-L1 EV 水平降低，不同患者组之间观察到不同水平的异质 PD-L1 EV。在免疫治疗期间，应答者表现出总 PD-L1 EV 和 T-PD-L1 EV 水平降低，同时 I-PD-L1 EV 水平降低。相反，无应答者表现出 I-PD-L1 EV 水平升高。利用楔形微流控芯片可以同时检测 PD-L1 EV 亚型，有助于精确预测口腔癌免疫治疗的结果。
