Effect of arsenic trioxide on apoptosis and cell cycle of NB4 cell

Objective To investigate the changes of apoptosis and cell cycle inducecd by arsenic trioxide(As_2O_3)inleukemia cell line NB4 cell in vitro. Methods NB4 cells were treated with As_2O_3 in different concentrations fo 12,24 and 36?h .The cytotoxity of NB4 cell were detectexd by(MTT)assay.The apoptotic cell was determined by Annexin V FITC-PI double staining method and measured by flow cytometry(FCM).Cell cycle was examined by PI fluoresence. Results 1～8?μmol/L As_2O_3 could induce NB4 cell in a time-and-dose dependent manner in vitro.2～8?μmol/L As_2O_3 could induce NB4 cell obvious apoptosis.The apoptosis rate of NB4 cells treated by As_2O_3 for 12 and 24?h showed a line relationship with the concention of As_2O_3,and for 36 and 48?h the NB4 cell mainly showed later apopotsis.Flow cytometry analysis showed that the number of G2/M phase cells increased gradually with raised concentrations treatment of As_2O_3. Conclusion As_2O_3 may inhibit the proliferation of NB4 cell.The mechanism is probably through blocking the cell cycle of G2/M phase and induced NB4 apoptosis in a time-and-dose dependent manner.