Quantitative Proteomic Analysis Reveals Different Functional Subtypes among IDH-Wildtype Glioblastoma

Purpose: Proteomics of glioma have not yet provided biomarkers and pathways that would clearly discriminate glioma subgroups. Methods: 82 glioma biopsies were prospectively collected and classified into six subgroups defined by methylomic classification: two low-grade glioma (LGG) and four high-grade glioma (HGG) subgroups. Proteins were extracted and processed for liquid chromatography–mass spectrometry (LC–MS). Differentially expressed proteins (DEPs) between subgroups were annotated, and functional validation was performed using inhibitor response assays in subtype-positive, patient-derived glioblastoma single-cell suspensions. Results: 5057 proteins were quantified for each sample. Tumor grading and IDH mutation status were the strongest discriminators for differential expression patterns. The glioblastoma IDH-wildtype subgroups showed diverse patterns of functions enriched with overexpressed DEPs: translation and cell cycle/telomere regulation in proneural glioblastoma (linked to cell proliferation), actin cytoskeleton, cell adhesion, and apoptosis regulation in classical glioblastoma (migration and invasion), and mitochondrial ATP synthesis in mesenchymal glioblastoma (metabolism). The most overexpressed proteins were correlated with survival and mRNA expression data. In vitro, inhibition of these proteins led to reduced cell viability that differed among subgroups, albeit in a small patient-derived exploratory cohort. Conclusion: This mainly descriptive study on proteomics in glioma provides insights into subgroup metabolism and potential biomarkers for further experimental testing.研究目的：目前胶质瘤蛋白质组学领域尚未发掘出可明确区分胶质瘤各亚型的生物标志物与信号通路。 研究方法：前瞻性收集82例胶质瘤活检样本，依据甲基化组分类标准将其划分为6个亚型：含2个低级别胶质瘤（low-grade glioma, LGG）亚型与4个高级别胶质瘤（high-grade glioma, HGG）亚型。提取样本蛋白质并进行液相色谱-质谱联用（liquid chromatography–mass spectrometry, LC-MS）检测。对各亚型间的差异表达蛋白（differentially expressed proteins, DEPs）进行功能注释，并通过患者来源胶质母细胞瘤单细胞悬液的抑制剂响应实验完成功能验证。 研究结果：所有样本均实现5057种蛋白质的定量检测。肿瘤分级与IDH突变状态是影响差异表达模式的最显著区分因素。IDH野生型胶质母细胞瘤各亚型的过表达差异蛋白富集功能呈现多样化特征：原神经型胶质母细胞瘤亚型中富集翻译与细胞周期/端粒调控通路（与细胞增殖密切相关），经典型胶质母细胞瘤亚型中富集肌动蛋白细胞骨架、细胞黏附与凋亡调控通路（与肿瘤迁移侵袭相关），而间质型胶质母细胞瘤亚型中富集线粒体ATP合成通路（与细胞代谢相关）。多数过表达蛋白与患者生存数据及mRNA表达水平存在显著相关性。体外实验中，抑制此类蛋白可降低细胞活力，且该效应存在亚型特异性差异，但本研究的患者来源探索队列规模较小。 研究结论：本项以描述性分析为主的胶质瘤蛋白质组学研究，为胶质瘤亚型代谢特征解析及后续实验验证的潜在生物标志物开发提供了重要见解。