ABSTRACT
Objective To study the effects of COX-2 selective inhibitor celecoxib on the apoptosis of acute promyelocytic leuke-mia NB4 cell line,and to investigate its apoptosis mechanisms.Methods The expression of COX-2 mRNA in different cell lines was detected by reverse transcript polymerase chain reaction(RT-PCR).After treatment of NB4 with different doses of celecoxib,the in-hibition of NB4 growth was assayed by MTT,and the DNA fragmentation was examined by the DNA ladder test.The level of Bcl-2 protein expression was assayed by the flow cytometry.Results As compared with the no-medication treatment group,the DNA ladder fragments became more and more obvious after the treatment by different doses of celecoxib.The expression rates of Bcl-2 protein in the different doses of celecoxib groups (25,50,100 μmol/L)were (71.69 ±1.65 )%,(34.51 ±2.53)% and (29.28 ± 2.38)% respectively,compared with the Bcl-2 protein expression rate (85.34±2.89%)in the blank control group,the expression rate of Bcl-2 protein in different doses of celecoxib groups(50,100 μmol/L )was significantly decreased(P <0.05 ).Conclusion Celecoxib as COX-2 selective inhibitor could evidently induce the apoptosis of NB4 cells by down-regulating the expression of Bcl-2 protein in NB4 cells.
ABSTRACT
Objective To investigate the relation between demethylation effect and apoptosis of valproate (VPA) in primary acute lymphoblastic leukemia (ALL) cells in vitro.Methods 10 cases of ALL patients was choosed to acquire leukemia cells.Cell growth curve were assessed by the MTT assay,the apoptosist of primary ALL was analyzed with DNA Ladder and Annexin-V-FITC/PI by flow cytometry.The expression methylation level of p15 was detected by hn-MSPCR,and p15mRNA were detected by RT-PCR.All dates was analyzed by SPSS16.0.Results The 50 ％ inhibition rate of VPA were 1.898 mmol/L to primary ALL cells assayed by MTT respectively.DNA ladder showed the apoptosis of primary ALL cells increased by adding VPA dose.Annexin-V-FITC/PI tests showed that the apoptosis percentage of primary ALL cells were (0.44±0.04) ％ in control group,(5.80±0.65) ％ in 1.0 mmol/L VPA group,(48.46±2.49) ％ in 2.0 mmol/L VPA group,(76.45±2.98) ％ in 4.0 mmol/L VPA group,the apoptosis percentage increased significantly (P ＜ 0.05).The demethylation of p15 INK4B gene decreased by adding VPA dose,the expression of p15 mRNA expression increased significantly compared with control group by RT-PCR (P ＜ 0.05).Conclusion It is found that VPA could induce demethylation of p15 INK4B gene,which could upregulate the p15 mRNA expression,due to the apoptosis of primary ALL cells.