Obesity and Tumor Development Reprogram the Proteome and Metabolic Effects of Adipose- and Tumor-Derived Extracellular Vesicles

Abstract Obesity alters systemic metabolism and immune function, yet how obesity and tumor progression regulate extracellular vesicle (EV) composition and function within the tumor microenvironment remains unclear. Using a preclinical model of diet-induced obesity (DIO) and triple-negative breast cancer (TNBC), we investigated how obesity and tumor stage shape the proteomic composition of EVs from visceral adipose tissue (VAT-EVs) and mammary tumors (tumor-EVs), and how these EVs regulate immune and tumor cell metabolism. Orthotopically transplanted metM-Wnt lung tumors were classified as early (∼0.5 cm³) or late (∼1.0 cm³), and EV proteomes were analyzed by mass spectrometry. At early stages, tumor-EVs from DIO mice, compared with control lean mice, were depleted in immune-related proteins, whereas VAT-EVs were enriched in mitochondrial and fatty acid oxidation proteins. In contrast, at later stages, tumor-EVs from DIO mice were enriched in lipid metabolism and oxidative stress–associated proteins, while VAT-EVs exhibited loss of mitochondrial proteins consistent with metabolic dysfunction. Functionally, tumor-EVs and VAT-EVs differentially regulated CD8 T cell mitochondrial activity and cytokine production and induced distinct, stage-dependent metabolic reprogramming in non-aggressive epithelial-like (E-Wnt) versus mesenchymal-like (M-Wnt) tumor cells. These findings suggest that obesity and tumor progression dynamically reshapes EV cargo, enabling EV-mediated metabolic reprogramming that may contribute to immune suppression and TNBC progression.