miR-181a sensitizes resistant leukaemia HL-60/Ara-C cells to Ara-C by inducing apoptosis
miR-181a sensitizes resistant leukaemia HL-60/Ara-C cells to Ara-C by inducing apoptosis
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DOI：
10.1007/s00432-011-1137-3
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发表时间：
2012-04-01
影响因子：
3.6
通讯作者：
Wang, Chun
中科院分区：
文献类型：
--
作者：
Bai, Haitao;Cao, Zhongwei;Wang, Chun
Ara-C是治疗AML最常用的药物之一。然而，耐药性的发展总是阻止其进一步使用。研究表明，miR-181 a与AML患者的临床结局相关。本研究通过实时荧光定量PCR检测miR-181 a在AML Ara-C耐药中的表达，探讨miR-181 a在AML Ara-C耐药中的作用。MTT法检测细胞活力。蛋白质印迹法测定蛋白质表达。荧光法检测Caspase活性，发现miR-181 a在Ara-C耐药细胞系HL-60/Ara-C中的表达较其亲本细胞系HL-60明显下调。miR-181 a在HL-60/Ara-C细胞中的过表达使细胞对Ara-C处理敏感。此外，通过免疫印迹分析和报告基因测定证实Bcl-2是miR-181 a的直接靶点。Bcl-2的敲低通过降低细胞活力模拟了强制miR-181 a表达的效果。此外，miR-181 a过表达后，细胞色素C的释放和caspase 9/caspase 3的激活了凋亡途径，本研究首次证实了白血病细胞中miR-181 a的下调和Bcl-2的上调导致了对阿糖胞苷治疗的抵抗。这些结果表明，miR-181 a表达的恢复可能为白血病耐药提供有希望的治疗。
Ara-C is one of the most commonly used drugs in the treatment of AML. However, the development of drug resistance always prevented its further use. It has been shown that miR-181a is associated with the clinical outcome of AML patients. Here, we investigated the possible role of miR-181a in AML Ara-C resistance.miR-181a expression was measured by real-time PCR. Cell viability was detected by MTT assay. Protein expressions were measured by western blotting. Caspase activity was examined by florescence assay.We found that miR-181a expression was downregulated in the Ara-C-resistant cell line HL-60/Ara-C compared with its parental cell line HL-60. Overexpression of miR-181a in HL-60/Ara-C cells sensitized the cells to Ara-C treatment. Furthermore, Bcl-2 was confirmed as a direct miR-181a target by immunoblot analysis and reporter gene assays. Knockdown of Bcl-2 mimicked the effect of enforced miR-181a expression by reducing cell viability. In addition, the apoptosis pathway was activated by cytochrome C release and caspase 9/caspase 3 activation after miR-181a overexpression.This study for the first time demonstrated that downregulation of miR-181a and upregulation of Bcl-2 in leukaemia cells confer resistance to Ara-C-based therapy. These results suggest that restoration of miR-181a expression might provide a promising therapeutic in drug resistance of leukaemia.