Oncogenic KRAS Regulates Secretion of Extracellular Vesicles and Surface Membrane Charge via Regulation of Phosphatidylserine in Pancreatic Cancer.

Extracellular vesicles (EVs) have the potential to be used as a liquid biopsy for cancer detection and treatment response assessment. Although the potential of EVs as disease-specific biomarkers has been promising, the rapid and specific enrichment of EVs from body fluids in a clinical setting remains challenging. To address this limitation, we developed a microfluidic electrophoresis (MEP) device for the label-free, charge-based enrichment of EVs from the serum of patients with pancreatic cancer (PaCa). We first validated the principle of charge-based cancer EV enrichment using cell-line-derived EVs, demonstrating that increased signaling through mutant Kirsten rat sarcoma viral oncogene homologue (KRAS), particularly KrasG12D, was associated with enhanced EV secretion and a shift toward more negative ζ-potential values. We then evaluated EVs derived from the serum of patients with PaCa to assess the clinical relevance and translational potential of the MEP platform. Further analyses identified phosphatidylserine and extraluminal DNA as part of the molecular determinants of the enhanced anionic nature of the PaCa-derived EVs. Overall, this proof-of-concept study introduces a promising microfluidic platform for enriching circulating cancer EVs with potential applications in the rapid detection of PaCa.