Hui Li

Exosomes facilitate therapeutic targeting of oncogenic KRAS in pancreatic cancer
Kamerkar S, LeBleu VS, Sugimoto H, Yang S, Ruivo CF, Melo SA, Lee JJ, Kalluri R.
Nature. 2017 Jun 22;546(7659):498-503. doi: 10.1038/nature22341. Epub 2017 Jun 7.
Department of Cancer Biology, Metastasis Research Center, University of Texas MD Anderson Cancer Center, Houston, Texas 77005, USA. Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal (I3S), 4200 Porto, Portugal; Institute of Pathology and Molecular Immunology of the University of Porto (IPATIMUP), 4200 Porto, Portugal. Department of Biostatistics, University of Texas MD Anderson Cancer Center, Houston, Texas 77005, USA.
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.
Date: 
July 12, 2017
Where: 
HSW 1057 at noon