Investigation On The Mechanism Of A549 Cells In The Killing Of NSCLC By Icotinib Combined With NK Cells

Objective:NK cells can co-express some activating and inhibitory receptors,which facilitate the recognition and instant lysis of allogeneic cells,infected cells and malignant cells,but safeguard healthy cells from attack.Natural killer group 2,member D(NKG2D)plays a critical role in the activation of NK cells and the interaction of NKG2D-NKG2D ligands enhances the NK cell mediated cytotoxicity.Thus,upregulation of NKG2D and/or its ligands is an attractive approach to activate NK cells and enhance its cytotoxic effect against cancer cells.whether icotinib,a novel EGFR-TKIs,can regulate NKG2D ligands expression was investigated.Methods:1.Cell Isolation and culture:NK cells are isolated from five healthy donors,PBMC first from peripheral blood mononuclear cells,using density gradient centrifugation.Then,according to the manufacturer’s instructions,the single cell suspension is purified with anti-CD56 magnetic beads and further cultured.2.Using CCK-8 to evaluate the kill activity of the A549,using lactate dehydrogenase to evaluate the cytotoxic action mediated by NK cells and flow cytometry to analyze the expression of nkg2d ligand in the cell.Result:1.NK cells can exert the cytotoxic effects on both A549 and PC9 cells.Moreover,there was no significant difference of the killing effect between these two cells.2.The expression levels of MICA/B and ULBP1 were increased significantly in the icotinib treated groups in compared to the control group.3.Compared with the control groups,the killing rates of NK cells on A549 cells were significantly increased by treatment with icotinib at any effective target ratio(1:1,5:1,20:1)tested.Conclusion:The expression of NKG2D ligand in A549 cells can be increased by Exeter,and the sensitivity of A549 cells to NK cells will increase.This study is instructive for the clinical application of EGFR TKIs combined with NK cell immunotherapy in the treatment of NSCLC.