Abstract：
WHO Grade 4 IDH-wild type astrocytoma (GBM) is the deadliest brain tumor with a poor prognosis. Meningioma (MMA) is a more common \"benign\" central nervous system tumor but with significant recurrence rates. There is an urgent need for brain tumor biomarkers for early diagnosis and effective treatment options. Extracellular vesicles (EVs) are tiny membrane-enclosed vesicles that play essential functions in cell-to-cell communications among tumor cells. We aimed to identify epitopes of brain tumor EVs by phage peptide libraries. EVs from GBM plasma, MMA plasma, or brain tumor cell lines were used to screen phage-displayed random peptide libraries to identify high-affinity peptides. We purified EVs from three GBM plasma pools (23 patients), one MMA pool (10 patients), and four brain tumor cell lines. We identified a total of 21 high-affinity phage peptides (12 unique) specific to brain tumor EVs. The peptides shared high sequence homologies among those selected by the same EVs. Dose-response ELISA demonstrated that phage peptides were specific to brain tumor EVs compared to controls. Peptide affinity purification identified unique brain tumor EV subpopulations. Significantly, GBM EV peptides inhibit brain tumor EV-induced complement-dependent cytotoxicity (necrosis) in neurons. We conclude that phage display technology could identify specific peptides to isolate and characterize tumor EVs.
摘要：
WHO4级IDH-野生型星形细胞瘤(GBM)是预后不良的最致命的脑肿瘤。脑膜瘤（MMA）是一种较常见的“良性”中枢神经系统肿瘤，但复发率高。迫切需要用于早期诊断和有效治疗选择的脑肿瘤生物标志物。细胞外囊泡（EV）是微小的膜封闭囊泡，在肿瘤细胞之间的细胞间通讯中起重要作用。我们旨在通过噬菌体肽文库鉴定脑肿瘤EV的表位。来自GBM等离子体的电动汽车，MMA等离子体，或脑肿瘤细胞系用于筛选噬菌体展示的随机肽文库以鉴定高亲和力肽。我们从三个GBM血浆池中纯化了EV（23名患者），一个MMA池（10名患者），和四种脑肿瘤细胞系。我们鉴定了总共21种对脑肿瘤EV具有特异性的高亲和力噬菌体肽（12种独特的）。这些肽在由相同EV选择的那些肽中共享高序列同源性。剂量反应ELISA表明，与对照相比，噬菌体肽对脑肿瘤EV具有特异性。肽亲和纯化鉴定了独特的脑肿瘤EV亚群。重要的是,GBMEV肽抑制脑肿瘤EV诱导的神经元补体依赖性细胞毒性(坏死)。我们得出的结论是，噬菌体展示技术可以鉴定特定的肽来分离和表征肿瘤EV。
