Data-Independent Acquisition Phosphoproteomics of Urinary Extracellular Vesicles Enables Renal Cell Carcinoma Grade Differentiation

Translating the research capability and knowledge in cancer signaling into clinical settings has been slow and ineffective. Recently, extracellular vesicles (EVs) have emerged as a promising source for developing disease phosphoprotein markers to monitor disease status. This study focuses on the development of a robust data -independent acquisition (DIA) using mass spectrometry to profile urinary EV phosphoproteomics for renal cell cancer (RCC) grades differentiation. We examined gas -phase fractionated library, direct DIA (library-free), forbidden zones, and several different windowing schemes. After the development of a DIA mass spec-trometry method for EV phosphoproteomics, we applied the strategy to identify and quantify urinary EV phospho-proteomes from 57 individuals representing low-grade clear cell RCC, high-grade clear cell RCC, chronic kid-ney disease, and healthy control individuals. Urinary EVs were efficiently isolated by functional magnetic beads, and EV phosphopeptides were subsequently enriched by PolyMAC. We quantified 2584 unique phosphosites and observed that multiple prominent cancer-related path-ways, such as ErbB signaling, renal cell carcinoma, and regulation of actin cytoskeleton, were only upregulated in high-grade clear cell RCC. These results show that EV phosphoproteome analysis utilizing our optimized pro-cedure of EV isolation, phosphopeptide enrichment, and DIA method provides a powerful tool for future clinical applications.

Automated summary

The translation of cancer signaling research into clinical application has been slow and ineffective. However, extracellular vesicles (EVs) show promise as a source for developing disease phosphoprotein markers. This study focuses on using mass spectrometry to profile urinary EV phosphoproteomics for renal cell cancer (RCC) differentiation. By optimizing the process of EV isolation, phosphopeptide enrichment, and DIA method, this study provides a powerful tool for future clinical applications.