As_2S_2诱导K562细胞凋亡的分子机制初步研究

Preliminary study on the molecular mechanism of K562 cell apoptosis induced by As_2S_2

目的 探索As2 S2 对K5 6 2细胞的诱导凋亡作用及其机制。方法 细胞凋亡的检测用流式细胞分析、基因组DNA电泳、细胞形态学观察等方法 ,Westernblot方法用于蛋白表达的检测 ,基因表达的变化用半定量RT PCR方法。结果 3～ 5 μmol L的As2 S2 作用 4 8～ 72h即可诱导K5 6 2细胞凋亡。 3μmol LAs2 S2 作用 72h时 ,细胞凋亡率达 (34.4± 3.3) % ;5 μmol LAs2 S2 作用 4 8,72h时 ,细胞凋亡率分别为 (2 1.8± 3.6 ) %和 (4 6 .0± 5 .2 ) %。 5 μmol LAs2 S2 作用下 ,As2 S2 可降低Bcr Abl和JAK2的蛋白含量。As2 S2 从基因水平上调bax表达 ,下调c myc表达。As2 S2 作用后 ,Caspase 3被激活。As2 S2 也能诱导慢性粒细胞性白血病 (CML)患者单个核细胞凋亡。结论 As2 S2 可诱导CML细胞凋亡 ,Bcr Abl含量的降低可能起了很重要的作用。bax表达的增加、c myc表达的减少、JAK2蛋白含量的降低以及Caspase 3激活也可能参与了该细胞凋亡机制。

Objective To investigate the apoptotic inducing effect of As 2S 2 on K562 cells. Methods The apoptotic inducing effect of As 2S 2 on K562 cells was determined by flow cytometry, DNA fragmentation analysis and morphology observation. Expression of protein was determined by Western blot. RT PCR was used to evaluate changes in gene expression. Results Apoptosis of K562 cells was induced by 48 72 h exposure to 5 μmol/L As 2S 2. Apoptosis was induced in (34.4±3.3)% treated cells by 72 h exposure to 3 μmol/L As 2S 2, in (21.8±3.6)% treated cells by 48 h exposure to 5 μmol/L As 2S 2 and in (46.0±5.2)% treated cells by 72 h exposure to As 2S 2 at the same concentration. With 5 μmol/L As 2S 2, the protein level of Bcr Abl and JAK2 decreased, while bax expression was upregulated and c myc was downregulated both in protein and mRNA level. The activity of caspase 3 in K562 cells was increased by As 2S 2. As 2S 2 also induced apoptosis of fresh mononuclear cells derived from chronic myelogenous leukemia (CML) patients. Conclusion As 2S 2 can induce apoptosis of CML cells. The decline of Bcr Abl may play an important role. The upregulation of bax, increase of the activity of caspase 3, downregulation of c myc and decrease of JAK2 may also be involved in the mechanism. [