Exploring strategies for efficient vectorized exosome-based therapy in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer, driven by KRAS mutations for which efficient treatment is currently missing. Exosome-based therapy composes a promising novel approach. However, the drawbacks of exosome therapy are the low targeting specificity of the drug-loaded exosomes and the high amounts of isolated exosomes necessary for an effective treatment. Here, I propose to (i) construct “vectorised” exosomes specifically targeting PDAC cells and optimized for delivering their anti-KRAS cargo in the cytoplasm of these cell (KRASVEX); (ii) test the specificity and effectiveness of anti-KRAS cargo delivery by KRASVEX in established PDAC cell lines, in patient-derived cells and in mice with orthotopic PDAC implants; (iii) optimize KRASVEX production by manipulating the producing cells for maximal exosome secretion. In practice, nanobodies directed against abundant PDAC proteins will be engineered and incorporated in the surface of exosomes. Different nanobodies will be tested and compared for effectiveness. Targeting different receptors, the expectation is that the exosomes will be differentially sorted upon uptake, leading to differential cargo delivery. It should be noted that exosomes need to fuse with the endosomal membrane to deliver their cargo to the cytoplasm. Thus, optimal delivery ways might include internalization routes avoiding or delaying lysosomal delivery. Lastly, manipulation of producing cells will help maximizing exosome secretion.