Abstract:

Objective To investigate the influence of icariin (ICA) on the proliferation and apoptosis of acute promyelocytic leukemia NB4 cells, and to explore its mechanism. Methods The NB4 cells at logarithm growth phase were selected and randomly divided into blank control group,different doses (4,8,16,32,64 μmol·L^-1) of ICA groups.Afer the NB4 cells were treated with ICA for different time (24,48,72 h),MTT assay was used to detect the inhibitory rates of NB4 cells,flow cytometry was used to analyze the apoptosis and the cell cycle of the NB4 cells,and the expression levels of apoptosis-associated proteins were detected by Western blotting method. Results Afer the cells were cultivated for different time(24,48,72 h),the inhibitory rates of the cells in different doses of ICA groups were higher than those in control group (P<0.05) and they were increased in a dose-and time-dependent manner (P<0.05).The apoptotic rates of NB4 cells in different doses of ICA group 48 h after treatment were (6.52±4.12)%,(10.07±2.36)%,(15.41±3.64)%,(25.18±1.24)% and (29.41±1.43)%,and they were higher than that in control group (2.39%±1.87%) (P<0.05).The flow cytometry results showed that after the cells were cultivated for 24 h in different doses of ICA groups,the number of NB4 cells at S phase was lower than those in control group (P<0.05),and the number of NB4 cells at G₁ phase was increased (P<0.05). The expression levels of Bcl-2 in ICA groups were significantly lower than that in control group (P<0.05),while the expression levels of Bax were higher than that in control group (P<0.05). Conclusion ICA can induce the apoptosis of NB4 cells via inhibiting the expression level of Bcl-2 and up-regulating the expression level of Bax.

Key words: Icaritin, leukemia, NB4 cells, apoptosis