microRNA-22对白血病K562细胞羟基脲化疗敏感性的影响

Effect of microRNA-22 on the chemosensitivity of human chronic myeloid leukemia K562 cells to hydroxyurea

对人慢性髓性白血病K562细胞进行羟基脲处理后高通量测序发现microRNA-22 (miR-22)表达量变化显著,上调达3.4倍。单基因GSEA分析提示miR-22可能调控白血病细胞对药物的响应。构建可诱导表达miR-22的K562细胞系,运用活细胞计数、流式细胞术、Caspase 3活性检测、Western blot和联苯胺染色等方法检测miR-22对羟基脲处理后K562细胞存活率、周期、凋亡和分化的影响。结果表明:过表达miR-22可导致K562细胞发生G0/G1期阻滞,从而帮助细胞逃逸羟基脲在S期的杀伤作用;过表达miR-22可显著拮抗羟基脲介导的sub-G1期细胞增多、Caspase 3活性上调、cleaved PARP1表达上调等凋亡现象;过表达miR-22还可促进羟基脲介导的红系分化。这一研究提示在K562细胞中,miR-22既可拮抗羟基脲化疗所致的细胞杀伤性效应(增殖、凋亡),也可促进羟基脲化疗所致的非细胞杀伤性效应(分化)。

miRNA sequencing of human K562 chronic myeloid leukemia cells revealed significantly 3.4-fold upregulated expression of miR-22 after treatment with hydroxyurea(HU). GESA analysis suggested that miR-22 might affect the chemosensitivity of leukemia cells to drugs. In the current study, we established a K562 cell line conditionally expressing miR-22, and employed live cell counting, flow cytometry, Caspase 3 activity analysis, Western blot and O-Tolidine staining to study the effects of miR-22 overexpression on the survival, cell cycle, apoptosis and differentiation status of K562 cells upon HU treatment. Overexpression of miR-22 resulted in G0/G1 phase arrest, which helped to escape the S-phase-specific cytotoxicity of HU. Overexpression of miR-22 also markedly alleviated HU-induced upregulation of sub-G1 cells, Caspase 3 activity and cleaved PARP1 expression level. In addition, overexpression of miR-22 promoted HU-mediated erythroid differentiation. These observations suggest dual roles of miR-22 in leukemogenesis: Reducing the sensitivity of K562 cells to HU-mediated cytotoxicity and enhancing the sensitivity of K562 cells to HU-mediated cell differentiation.