Expression of MICA in oral squamous carcinoma cells and its effect on NK cells

Objective: This study aims to observe the expression of MHC-class I chain related protein A (MICA) in oral squamous carcinoma cell and explore its effects on NK cells. Methods: Normal oral mucosa epithelial cell line NOK and oral squamous carcinoma cell lines OEC-M1, SAS and SCC-25 were used in this study. MICA expression in the cells was detected by western blotting and RT-PCR methods, sMICA was detected by ELISA method. The cells were transfected by pEGFP-MICA and pEGFP-NC respectively using Lipofectamine 2000 kit. The transfected cells were co-cultured with NK92 cells. Killing activity of NK92 cells was detected by LDH release method and NKG2D was detected by Flow cytometry. ADAM10 and ADAM17 were detected by ELISA method. Results: MICA expression in OEC-M1, SAS and SCC-25 cells were lower than that of NOK cells (P < 0.01), sMICA levels in OEC-M1, SAS and SCC-25 cells were higher than that of NOK cells (P < 0.01). Over-expression of MICA in SCC-25 cells could significantly increase the killing activity of NK92 cells (P < 0.01), up-regulate NKG2D (P < 0.01) and decrease ADAM10 and ADAM17 contents (P < 0.01). Conclusions: MICA expressed lowly in oral squamous cell carcinoma cells, over-expression of MICA could significantly increase the killing activity of NK92 cells, which could be related with the regulation of ADAM.