Research on inhibitory effect of YC-1 on proliferation of human leukemia U937,THP-1 cell lines

Objective To delineate the potency of YC-1 on the proliferation,apoptosis,cell cycle and the protein expression of Caspase-3,-8,-9 in U937 and THP-1 leukemia cell lines.Methods MTT assay was performed to detect proliferation.Flow cytometry was used to measure the apoptosis and cell cycle.The expression of Caspase-3,-8 and-9 were detected by Western blot.Results The MTT assay showed that cell proliferation was inhibited in a concentration-dependent manner in 1.0,3.0,10.0 μmol/L YC-l-treated U937 and THP-1 cells.The survival rates for YC-1 after 24 h in U937 cells were (76.5±4.4) ％,(68.7±6.8) ％,(60.9±13.2) ％ respectively and (94.1±1.4) ％,(81.4±2.0) ％,(72.7±3.0) ％ respectively in THP-1 cell,compared with the control group (100 ％),there were significant differences (F =15.870,126.629,P ＜ 0.01).The apoptosis rates for 1.0,3.0,10.0 μmol/L YC-1 after 24 h were (40.7±1.0) ％,(55.6±2.3) ％,(71.8±1.5) ％respectively in U937 cells and (34.6±2.0) ％,(50.3±3.5) ％,(59.6±4.6) ％ respectively in THP-1 cells.With the control group (4.7±1.4) ％,(1.8±1.0) ％,there were significant difference (F =937.229,200.447,P ＜ 0.01).However,there was no significant difference for cell cycle.In addition,Cleaved Caspase-8 and Cleaved Caspase-3 expression after 1.0,3.0,10.0 μmol/L YC-1 treated for 24 h were significantly higher than control,but the expression of Caspase-9 did not appear significant change in U937 cells.As the same concentration and time point,Cleaved Caspase-3 expression increased with no change of Caspase-9 or Caspase-8 in THP-1 cells.Conclusion YC-1 effectively suppress the proliferation with little effect on cell cycle,but induce the apoptosis,have no effect on cell cycle,and the mechanism of apoptosis may be related to the Caspase activation in U937 and THP-1 cell lines. Key words: Leukemia, experimental;  Hypoxia-inclucible factor 1 inhibitor;  Cell cycle; Apoptosis;  Caspase