Nanobody-Decorated Lipid Nanoparticles for Enhanced mRNA Delivery to Tumors In Vivo

Prostate cancer (PCa) ranks as the fifth leading cause of cancer-related deaths among men worldwide. In 10-20% of the cases, PCa progresses to an incurable, castration-resistant stage. Castration-resistant PCa cells often overexpress prostate-specific membrane antigen (PSMA), a membrane protein that may serve as their Achilles' heel. Over the past decades, RNA-based therapeutics have emerged as promising treatments for a vast array of diseases, including cancer. In this study, with the ultimate goal of developing a targeted therapy for PCa, lipid nanoparticles (LNPs) are decorated with an anti-PSMA nanobody using click chemistry with a PEG-lipid. Direct stochastic optical reconstruction microscopy (dSTORM) and cluster analysis confirm the presence of at least one nanobody on the surface of 80% of LNPs. These anti-PSMA LNPs exhibit enhanced and specific uptake, and mRNA transfection in PSMA+ cancer cells both in vitro and in a Zebrafish (ZF) metastatic PCa xenograft model. Additionally, in a mouse PSMA-positive xenograft model, systemic administration results in increased LNP accumulation, but not functional mRNA delivery. These findings underscore both the potential and the challenges of using a PSMA-targeted lipid nanoparticle system for mRNA delivery into advanced prostate cancer tumors.