Development of Methods to Modulate Natural Killer Cells

Natural Killer (NK) cell based immunotherapies have demonstrated success against malignancies and hematological cancers. However, tumors have developed mechanisms to evade detection by and suppress the immune system, commonly through altering the expression of cell-surface proteins. Overexpression of human leukocyte antigen-E (HLA-E), which binds to the inhibitory NKG2A on NK cells, protects malignant cells from lysis. Downregulating the NKG2A receptor on NK cells should release NK cell inhibition, but proves challenging as NK cells are difficult to transfect and no good methods currently exist. This project is designed to investigate the use of exosomes – small vesicles and natural carriers of regulatory microRNAs (miRNAs) and proteins that are shed from cells – as delivery vehicles for small RNAs (sRNAs) to immune cells. Exosomes are biologically compatible, immunologically inert, and interact with target cells through receptor-ligand interactions, allowing for targeted delivery of cargo. Exosomes loaded with shRNA against NKG2A were cultured in vitro with NK cells. Delivery success was assessed by monitoring NKG2A receptor expression on NK cells through flow cytometry. This research will provide valuable information that will likely impact the delivery of RNA therapeutics and unlock the full cytotoxic potential of NK immunotherapy