Proteomics of Prostate Cancer Tissue Small Extracellular Vesicles Reveal Alteration of Metabolism

Prostate cancer (PCa) is a leading male malignancy worldwide, with metabolic reprogramming being a critical hallmark of its progression. Extracellular vesicles (EVs) derived from tissues directly reflect the tumor microenvironment, offering unique insights into cancer pathophysiology that are unattainable through cell line or biofluid-derived EVs. However, the functional roles of tissue-derived EVs in PCa metabolism remain poorly understood. Leveraging our expertise in murine PCa model establishment and EV isolation from prostate tissue, this study aimed to characterize functional differences between PCa and normal prostate tissue via proteomic analysis of tissue-derived small EVs (sEVs). We orthotopically implanted luciferase-labeled PCa cells into nude mice to establish an in situ PCa model, confirmed tumor formation via in vivo imaging, and harvested tissues after four weeks. sEVs were isolated using ultracentrifugation combined with an iodixanol density cushion and characterized by transmission electron microscopy, nanoparticle tracking analysis, and protein marker profiling. Proteomic analysis identified 28 upregulated and 24 downregulated proteins in PCa-derived sEVs compared to normal controls. Subcellular localization revealed enrichment in the cytoplasm, while pathway analysis highlighted significant involvement in metabolic processes, particularly glycolysis, amino acid biogenesis, carbon metabolism, and pyruvate metabolism. Our study establishes a robust method for isolating prostate tissue sEVs and provides the first evidence that PCa tissue-derived sEVs exhibit profound metabolic pathway alterations. These findings enhance our understanding of PCa progression mechanisms and may facilitate the development of novel diagnostic biomarkers and therapeutic strategies targeting metabolic dysregulation in PCa.