Flavone from Galium Verum L induces apoptosis in acute promyelocytic leukemia cells(NB4)

Objective To study anti-proliferation and apoptosis promotion effect of flavone from Galliu Verum L(FGVL)on acute promyelocytic leukemia cells(NB4)and its possible mechanisms.Methods The proliferation inhibition of NB4 cells was detected with 3-(4,5)dimethylthiazol-2-yl-2,5-di-phenyltetrazolium bromide(MTT).DNA agarose electrophoresis was used to detect cell apotosis and acridine orange ethidium bromide(AO/EB)staining was used to observe morphological changes of NB4 cells.The expression of pro- and anti-apoptotic genes Bax and Bcl-2 were examined with reverse transcription polymerase chain reaction.Results FGVL at the doses of 50,100,and 200 μg·mL^-1 could effectively inhibit the proliferation of NB4 cells,with the cell proliferation inhibition rates of 6.7%,7.4%,24.3%for 24 hours treatment,2.3%,18%,45.9%for 48 hours and 3.7%,24%,51.7%for 72 hours treatment,respectively.Morphology change observation indicated characteristics of cell apoptosis and the DNA agarose electrophoresis showed typical DNA ladder.FGVL could upregulate Bax mRNA and downregulate mRNA level of Bcl-2 in NB4 cells and the effect was positively correlated with the dose and treatment time.Conclusion FGVL could significantly induce apoptosis of NB4 cells,which might be related to the down-regulation of Bcl-2 and up-regulation of Bax.