Abstract
New treatment strategies are urgently needed for pancreatic ductal adenocarcinoma (PDAC), which is one of the deadliest tumors nowadays. PDAC is marked by hypoxia, intrinsic chemoresistance, a "cold" tumor microenvironment, and dense desmoplastic stroma, which hinders drug penetration. This study investigates the combined effect of iron-doped, lipid-coated zinc oxide nanoparticles enhanced with a fluorescent sonosensitizer and local ultrasound stimulation in treating PDAC. Nanoparticles were synthesized and coated by lipids, and their physiochemical properties were characterized by assessing reproducibility, stability, and efficient inclusion of the sonosensitizer. In vitro, sonosensitizer-enhanced nanoconstructs were tested on a KPC murine PDAC cell line in combination with ultrasound to evaluate their cytotoxicity and assess their efficacy. In vivo, NPs were further coupled with AlexaFluor 700 to allow their localization over time, and the nanoconstructs were intratumorally administered to a subcutaneous murine PDAC model to enhance local bioavailability and tumor visualization and minimize off-target effects of systemic delivery. Biodistribution, efficacy, flow cytometry, and survival studies were carried out on different cohorts of mice. The sonosensitizer-enhanced nanoconstructs, combined with ultrasound, triggered significant reactive oxygen species (ROS) production, reducing the KPC cell viability. In vivo, the antitumor efficacy was particularly pronounced with ultrasound stimulation, demonstrating a synergistic interaction between the nanoparticles and ultrasound. Moreover, increased immune cell infiltration, enhanced cancer cell apoptosis, and prolonged survival of the treated animals were achieved. These findings highlight the potential of a synergistic therapeutic approach combining lipid-coated sonosensitizer-loaded nanoparticles and ultrasound stimulation as an effective therapy for PDAC and in situ monitoring.