Molecular Characterization of Small Extracellular Vesicles in Pancreatic Cancer Patients Treated with Neoadjuvant...

Background/Objectives: Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with limited therapeutic options, a high mortality rate, and poor overall survival, necessitating the development of new therapeutic and diagnostic strategies. This study investigated the potential of plasma-derived small extracellular vesicles (sEVs) as a source of molecular biomarkers associated with the treatment response. Methods: Plasma samples were obtained from patients with locally advanced and borderline resectable PDAC at baseline and following neoadjuvant chemotherapy, either FOLFIRINOX (5-FU [fluorouracil], leucovorin, oxaliplatin, and irinotecan) or GEM-ABRAX ( gemcitabine plus nab-paclitaxel), followed by stereotactic body radiation therapy (SBRT). sEVs were isolated from plasma at baseline, after neoadjuvant chemotherapy, and following SBRT, and were characterized by nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), nano-flow cytometry, and real-time PCR (RT-PCR). Results: The isolated sEVs exhibited an average size of <200 nm, expressed canonical exosome markers (CD63 and CD9), and exhibited pancreatic cancer (PanC)-associated markers, including cholecystokinin A receptor (CCK-AR) and carbohydrate antigen 19-9 (CA19-9). The sEV cargo included several PanC-associated microRNAs (miRNAs). Notably, the expression profiles of these miRNAs demonstrated interpatient variability, though a subset of miRNAs showed statistically significant changes following treatment. Conclusions: These findings support the feasibility of sEV isolation and molecular profiling from patient plasma and warrant further investigation as a potential source of biomarkers in pancreatic cancer.