Mechanism of apoptosis in human leukemia NB4 cells induced by total astragalosides

Objective To investigate the effect of total astragalosides （TA） on proliferation and apoptosis in human leukemia NB4 cells in vitro. Methods The NB4 cells were treated with TA at different concentrations for 48 h in culture. Growth inhibition rates were measured by CCK-8 method. Flow cytometry was used to explore the cell apoptosis and the activity of NF-κB and Akt during apoptosis. Results TA at different concentrations （200, 400, 600, 800 mg/L） inhibited proliferation of NB4 cells in a dose-dependent manner （ P 〈 0. 05）, and the inhibitory rates of TA on NB4 cells were （14. 54 ± 3. 20） % , （24.79 ±3.98）%, （57.28 ±4.71）% and （88.28 ±4.65）% , respectively. In terms of the induction of apoptosis, there was a significant difference between the TA group and blank control [（1.80±1.24）%, P〈0.05]. At TA doses of 200, 400 and 600 mg/L, the apoptotic rates of NB4 cells were （ 10. 03 ± 3.31）% , （14.87 ±3.65）% , （23.45 ± 1.90） % , respectively. Besides, TA induced apoptosis of NB4 cells in a dose-dependent manner in the groups of 200 mg/L, 400 mg/L, 600 mg/L （P〈0.05）. But there was no significant difference in apoptotic rates between the groups of 800 mg/L and 600 mg/L [（23.45 ±1.90）%, P〉 0.05]. In the group of 800 mg/L, the necrotic cells increased highly and the necrotic rate reached （45.65 ± 3.16）%. After TA treatment of NB4 cells at different concentrations （200, 400, 600 mg/L）, the expression of NF-kB protein was significantly decreased compared with that of the blank control （9. 79 ±0. 95, P〈0.05）, while Akt protein was not significantly decreased （P〉0.05）. Conclusion TA can inhibit the growth of NB4 cells and induce apoptosis in NB4 cells through an Akt-independent NF-kB signaling pathway. Key words: Leukemia ;  Total astragalosides ;  Apoptosis ;  Cell proliferation