目的：探讨下调miR-221 对慢性粒细胞白血病（CML）K562 细胞增殖和凋亡的影响及其相关的调控机制。方法：将K562 细胞分为对照组、miRNA阴性对照（miR-NC）组、miR-221 inhibitor 组、miR-221 inhibitor+阴性对照siRNA（NC siRNA）组和miR-221 inhibitor+SOCS3 siRNA 组。其中，对照组细胞不进行另外处理；miR-NC 组和miR-221 inhibitor 组分别采用miR-NC 和miR-221 inhibitor 转染至细胞；miR-221 inhibitor+NC siRNA 组和miR-221 inhibitor+SOCS3 siRNA 组采用已稳定转染miR-221 inhibitor的细胞再分别转染NC siRNA 和SOCS3 siRNA。用qPCR鉴定miR-221 inhibitor 的转染效率，CCK-8 法检测各组细胞的增殖活性，Annexin V-FITC/PI 双染色流式术检测各组细胞的凋亡水平，WB实验检测各组细胞的SOCS3、p-JAK1、p-JAK2、p-STAT3和survivin 的蛋白表达水平。结果：与对照组比较，miR-221 inhibitor 组细胞内miR-221 的表达显著下调（P<0.01），细胞增殖活性在转染后48、72 h 时明显降低（P<0.05 或P<0.01），凋亡细胞数量明显增加（P<0.01），细胞内SOCS3 的表达水平明显增加（P<0.01），而p-JAK1、p-JAK2、p-STAT3 和survivin 的表达水平均明显降低（均P<0.01）。与miR-221 inhibitor 组比较，miR-221 inhibitor+SOCS3 siRNA组细胞增殖活性在转染后24、48 和72 h 时明显增加（P<0.05 或P<0.01），凋亡细胞数量明显减少（P<0.01），细胞内p-JAK1、p-JAK2、p-STAT3 和survivin 的表达水平均明显增加（均P<0.01）。结论：下调miR-221 可能通过上调SOCS3 表达抑制JAK-STAT3 信号通路，从而抑制K562 细胞增殖并促进其凋亡。

Objective: To investigate the effect of down-regulation of miR-221 on cell proliferation and apoptosis of chronic myeloid leukemia (CML) K562 cells and its related regulatory mechanism. Methods: K562 cells were divided into control group, miRNA negative control (miR-NC) group, miR-221 inhibitor group, miR-221 inhibitor+ negative control siRNA (NC siRNA) group and miR-221 inhibitor+ SOCS3 siRNA group. The cells in the control group received no additional treatment. Cells in miR-NC group and miR-221 inhibitor group were transfected with miR-NC and miR-221 inhibitor, respectively. Cells in miR-221 inhibitor+NC siRNA group and miR-221 inhibitor+SOCS3 siRNA group were transfected with NC siRNA and SOCS3 siRNA, respectively, on the basis of successful transfection with miR-221 inhibitor. The transfection efficiency of miR-221 inhibitor was identified by qPCR. Cell viability in each group was measured by CCK-8 assay. Apoptosis in each group was detected by Annexin V-FITC/PI staining using a flow cytometry.The protein expressions of SOCS3, p-JAK1, p-JAK2, p-STAT3 and survivin in each group were detected by WB. Results: Compared with the control group, miR-221 expression was significantly down-regulated in miR-221 inhibitor group (P<0.01), cell viability was significantly reduced at 48 and 72 h after transfection (P<0.05 or P<0.01), the number of apoptotic cells was significantly increased (P<0.01), the expression of SOCS3 was significantly increased (P<0.01) and the expression levels of p-JAK1, p-JAK2, p-STAT3 and survivin were significantly reduced (all P<0.01). Compared with miR-221 inhibitor group, cell viability was significantly increased at 24,48 and 72 h after transfection (P<0.05 or P<0.01), the number of apoptotic cells was significantly decreased (P<0.01) and the expression levels of p-JAK1, p-JAK2, p-STAT3 and survivin were significantly increased in miR-221 inhibitor+SOCS3 siRNA group (all P<0.01). Conclusion: Down-regulation of miR-221 inhibits proliferation and promotes apoptosis of K562 cells, the mechanism of which may be related with up-regulating SOCS3 expression to suppress JAK-STAT3 signaling pathway.

河北省指令性课题计划资助项目（No.ZL20140057）