Abstract: Objective To investigate the regulation and mechanism of interleukin-33（IL-33） on the apoptosis and cell cycle of acute myeloid leukemia (AML) cells HL-60 and NB4. Methods AML cell lines HL-60 and NB4 were treated with IL-33 and p38 mitogen-activated protein kinase（p38 MAPK） inhibitor (SB203580) for 72 h. The cell apoptosis rate was detected by Annexin V/DAPI double staining flow cytometry and the cell cycle was detected by cell cycle detection kit. The expression levels of CDK1 protein and p38 MAPK phosphorylation were detected by Western blot. Results Compared with the control group, the apoptosis level of HL-60 and NB4 cells in IL-33 group was reduced after IL-33 treatment (P<0.05), the proportion of S phase in cell cycle increased (P<0.001); while the apoptosis level of SB+IL-33 group was higher than that of IL-33 group after combined treatment with SB203580 and IL-33 (P<0.05), and the percentage of S phase cells was lower than that of IL-33 group (P<0.05). Western blot results showed that the phosphorylation level of p38 MAPK (p-p38 MAPK) and the expression level of CDK1 protein were significantly increased in IL-33 group, compared with the control group (all P<0.05). The expression levels of p-p38 MAPK and CDK1 in SB+IL-33 group were significantly lower than those in IL-33 group (all P<0.05). Conclusions IL-33 can inhibit apoptosis and cell cycle of AML cell lines HL-60 and NB4 by activating p38 MAPK.

Key words: Acute myeloid leukemia, IL-33, Cell cycle, Apoptosis