Cisplatin Induces Up-regulation of NKG2D Ligands and Enhances Natural Killer Cell Lysis of Nasopharyngeal Carcinoma Cells

Objective To explore the effects of Cisplatin(DDP) on the expression of NKG2D ligands and HLA-class Ⅰ molecules on human nasopharyngeal carcinoma cell line (CNE2) and natural killer (NK)cells cytotoxicity. Methods The IC₅₀ of DDP against CNE2 cells were measured by MTT assay. Cytotoxicities of NK cells isolated from 3 healthy volunteers against CNE2 cells before and after cultured by DDP were analyzed by LDH releasing assay at effector-to-target cell ratio(E∶T) of 20∶1. The expression of NKG2D ligands(MICA/B, ULBP1, ULBP2, ULBP3), HLA-classⅠmolecules before and after treated by DDP were assayed by flow cytometery. Results DDP could decrease the proliferation and survival rate of CNE2 cells. The IC₅₀ was 5mg/L. The cytotoxicity of NK cells against CNE2 cells cultured by DDP was significantly enhanced. The expression of NKG2D ligands(MICA/B, ULBP1, ULBP3) of CNE2 cells were up-expressed after cultured with DDP. There were no significant difference of expression of ULBP2 and HLA-classⅠmolecules before and after treated by DDP(P>0.05). Conclusion The results indicate that DDP up-regulated the expressions of MICA/B, ULBP-1, ULBP-3, which enhanced the susceptibility of CNE2 cells to natural killer cell-mediated lysis.