Search

The mutant form of the GTPase KRAS is a key driver of pancreatic cancer but remains a challenging therapeutic target. Exosomes are extracellular vesicles generated by all cells, and are naturally present in the blood. Here we show that enhanced retention of exosomes, compared to liposomes, in the circulation of mice is likely due to CD47-mediated protection of exosomes from phagocytosis by monocytes and macrophages. Exosomes derived from normal fibroblast-like mesenchymal cells were engineered to carry short interfering RNA or short hairpin RNA specific to oncogenic KrasG12D, a common mutation in pancreatic cancer. Compared to liposomes, the engineered exosomes (known as iExosomes) target oncogenic KRAS with an enhanced efficacy that is dependent on CD47, and is facilitated by macropinocytosis. Treatment with iExosomes suppressed cancer in multiple mouse models of pancreatic cancer and significantly increased overall survival. Our results demonstrate an approach for direct and specific targeting of oncogenic KRAS in tumours using iExosomes.

Exosomes are extracellular vesicles produced by all cells with a remarkable ability to efficiently transfer genetic material, including exogenously loaded siRNA, to cancer cells. Here, we report on a bioreactor-based, large-scale production of clinical-grade exosomes employing good manufacturing practice (GMP) standards. A standard operating procedure was established to generate engineered exosomes with the ability to target oncogenic Kras (iExosomes). The clinical-grade GMP iExosomes were tested in multiple in vitro and in vivo studies to confirm suppression of oncogenic Kras and an increase in the survival of several mouse models with pancreatic cancer. We perform studies to determine the shelf life, biodistribution, toxicology profile, and efficacy in combination with chemotherapy to inform future clinical testing of GMP iExosomes. Collectively, this report illustrates the process and feasibility of generating clinical-grade exosomes for various therapies of human diseases.