ABSTRACT
OBJECTIVE@#To investigate the effect of chidamide on the killing activity of NK (Natural killer cell, NK) cells targeting K562 cells and its related mechanism.@*METHODS@#K562 cells were pretreated with chidamide at different concentrations and cocultured with NK cells at different effect-target ratios. The killing effect of chidamide on K562 cells by NK cells, the expression of natural killer group 2 member D (NKG2D) ligands and apoptosis rate of K562 cells were detected by flow cytometry.@*RESULTS@#The killing sensitivity of NK cells to K562 cells could be enhanced by chidamide. The expression of ULBP2 on K562 cell surface could be up-regulate, however, the expression of ULBP1 and MICA/MICB showed no statistically difference as compared with control group. Chidamide showed no obvious cytotoxicity to K562 cells.@*CONCLUSION@#Chidamide can significantly improve killing efficiency of NK cells on K562 cells, which may be related to the up-regulation of ULBP2 expression.