5-AZA-CdR联合EGCG对HL-60和K562的影响

目的 探讨细胞因子INFα和甲基化抑制剂5-杂氮脱氧胞嘧啶核苷(5-AZA-CdR)能否诱导HL-60和K562 Xaf1表达,以及Xafl表达诱导剂联合表没食子儿茶素没食子酸酯(EGCG)是否具有协同抗癌作用.方法 (1)1000U/mlINFα和不同剂量的5-AZA-CdR作用于HL-60和K562 48 h.通过RT-PCR检测Xaf1和XIAP mRNA的表达并比较差异.(2)最佳Xaf1表达诱导剂联合EGCG作用于白血病细胞,流式细胞技术检测Bcl-2家族成员、线粒体膜电位和细胞凋亡的情况.结果 (1)随5-AZA-CdR剂量增加,HL-60和K562 Xaf1 mRNA表达增加,INFα也能诱导Xaf1表达,以5-AZA-CdR(5 μmol/L)的作用最强;ISFα和5-AZA-CdR均不影响XIAP mRNA的表达.(2)5-AZA-CdR和EGCG可改变HL-60和K562细胞Bcl-2(Bcl-x1)和Bax的表达,降低线粒体膜电位,诱导细胞凋亡,二者联合作用被加强.结论 (1)INFα和5-AZA-CdR能诱导HL-60和K562 Xaf1 mRNA的表达,且5-AZA-CdR的作用具有剂量依赖性.(2)5-AZA-CdR和EGCG在体外能诱导白血病细胞凋亡,并具有协同效应.

Effect of (-)-epigallocatechin-3-gallate and 5-AZA-CdR on expression of X-linked inhibitor of apoptosis protein-associated factor 1 in human leukemia HL-60 and K562 cells

OBJECTIVE: To study the expression of X-linked inhibitor of apoptosis protein (XIAP)-associated factor 1 (Xaf1) in human leukemia HL-60 and K562 cells treated with interferon alpha (INFalpha) and the demethylating agent 5-AZA-CdR, and observe the synergetic antitumor effect of Xaf1 inducer and (-)-epigallocatechin-3-gallate (EGCG). METHODS: Human leukemia HL-60 and K562 cells were treated for 48 h with 1000 U/ml INFalpha and different doses of 5-AZA-CdR, and the mRNA expressions of both Xaf1 and XIAP were measured by RT-PCR. The leukemia cells were also treated with the optimal Xaf1 inducer in combination with EGCG, after which flow cytometry was employed to examine the changes in the members of the Bcl-2 family, mitochondrial transmembrane potential and apoptosis. RESULTS: As the dose increased, 5-AZA-CdR dose-dependently up-regulated the mRNA expression of Xaf1 in HL-60 and K562 cells; INFalpha treatment also resulted in increased Xaf1 expression, but 5 micromol/L 5-AZA-CdR showed the most potent effect. Neither INFalpha nor 5-AZA-CdR caused significant changes in XIAP expression. Combined treatment with 5-AZA-CdR and EGCG altered the expressions of Bcl-2 (Bcl-xl) and Bax in HL-60 and K562 cells, decreased the mitochondrial transmembrane potential and induced cell apoposis, and the two agents exhibited obvious synergistic effect. CONCLUSION: INFalpha and 5-AZA-CdR can induce Xaf1 mRNA expressions in HL-60 and K562 cells, and the effect of 5-AZA-CdR was dose-dependent. 5-AZA-CdR and EGCG induces apoptosis of leukemia cells in vitro, and they exhibits obvious synergetic effects.