硒和维生素E对白血病细胞凋亡及c-Myc基因表达的影响

目的 :　研究 Se和 VE对白血病细胞凋亡及 c- Myc基因表达的影响。方法 :　体外培养白血病细胞株 HL- 6 0、K5 6 2 ,培养时分别添加 Se(8μmol/L)和 VE(1 0 0 μmol/L)。利用 DNA凝胶电泳技术及 Northern杂交技术检测细胞凋亡和癌基因表达。结果 :　Se和 VE均能诱导白血病细胞 HL- 6 0和 K5 6 2细胞凋亡。VE(1 0 0 μmol/L)能够抑制 HL- 6 0细胞中 c- Myc基因的表达 ,结果有显著性 ;VE却不能抑制 K5 6 2细胞内 c- Myc基因的表达。相反 ,Se(8μmol/L)不能够抑制 HL-6 0细胞中 c- Myc基因的表达 ,却能抑制 K5 6 2细胞内 c- Myc基因的表达 ,结果有显著性。结论 :　抑制 c- Myc基因的表达 ,诱导白血病细胞凋亡是 Se、VE抑制白血病细胞增殖的重要途径之一。对于髓系和非髓系白血病细胞 ,Se与 VE对 c- Myc基因的表达的影响迥然不同 ,提示二者的作用机制是不同的。

EFFECTS OF SELENIUM AND VITAMIN E ON APOPTOSIS AND C-MYC EXPRESSION IN LEUKEMIC CELLS

Objective: To study the effects of vitamin E and selenium on apoptosis and c-Myc expression in human leukemia cells. Methods: DNA gel electrophoresis and Northern blotting hybridization were used to detect the apoptosis and the expression of c-Myc gene, respectively. Human leukemia cell line HL-60 and K562 were cultured in vitro. Results: The apoptosis of HL-60 and K562 cells were induced after being exposed to vitamin E (100 μmol/L) and selenium (8 μmol/L) for 24 hours, respectively. In HL-60 cell line, c-Myc mRNA was down-regulated significantly by vitamin E(100 μmol/L),but not selenium(8 μmol/L).In contrast, the expression of c-Myc gene was repressed by selenium(8 μmol/L) and not by vitamin E(100 μmol/L) in K562 cell. Conclusion: Our observations suggest that c-Myc down-regulation and induction of apoptosis by selenium and vitamin E are important pathways in repressing leukemia cell proliferation.The results suggest there are different mechanisms of repressing leukemia cell proliferation for selenium and vitamin E.