[Different cytotoxicity of NK cells against high and low expression of ATP-binding cassette transporter (ABCG(2)) of human multi-drug resistant nasopharyngeal carcinoma cells].

AIM

To investigate the different cytotoxicity sensitivity of high and low expression of ATP-binding cassette transporter (ABCG(2)) of human multi-drug resistant nasopharyngeal carcinoma CNE2/DDP cell line (ABCG(2)(High) cell and ABCG(2)(Low cell)) to NK cells.

METHODS

ABCG(2)(High)CNE2/DDP cells, ABCG(2)(Low) CNE2/DDP cells and NK cells were isolated by magnetic activated cell sorting (MACS). The cytotoxic effects of NK cells against K562, ABCG(2)(High) and ABCG(2)(Low)CNE2/DDP cells were detected with LDH releasing assay. The apoptosis rate and expression of NKG2D-ligands on target cells were evaluated by FCM.

RESULTS

The expression of ABCG(2) in ABCG(2)(High) CNE2/DDP and ABCG(2)(Low) CNE2/DDP cells was (91.40+/-2.32)% and (1.70+/-0.24)%, respectively. More than 90% of the isolated NK cells were CD3(-)CD16(+)CD56(+) cells. As for the cytotoxicity of NK cells against ABCG(2)(Low), ABCG(2)(High)CNE2/DDP and K562 cells at the E vs T ratio of 10 vs 1 and 20 vs 1, ABCG(2)(High) CNE2/DDP cells possessed highest cytotoxic sensitivity. The apoptosis rate of ABCG(2)(High) CNE2/DDP cells and ABCG(2)(Low)CNE2/DDP cells was (12.90+/-1.51)% and (6.13+/-0.85)%, respectively. The expression of five kinds of NKG2D ligand of ABCG(2);(High)CNE2/DDP cells is higher than that of ABCG(2)(Low)CNE2/DDP cells.

CONCLUSION

ABCG(2)(High) CNE2/DDP cells are more sensitive to NK cells than ABCG(2)(Low) CNE2/DDP cells in cytotoxicity because the expression of NKG2D ligands of ABCG(2)(High)CNE2/DDP cells is higher than that of ABCG(2)(Low)CNE2/DDP cells, which results in the cytotoxic sensitivity of increased tumor cells to NK cells.