Molecular mechanism of apoptosis induced by valproate in primary cells from acute lymphoblastic leukemia in vitro

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. Key words: Leukemia, lymphocytic, acute; Valproate; Primary cells; p15 gene; Methylation