Objective: To investigate the K562 cells biological function and related molecular changes in PTEN-PI3K/AKT signaling pathway of leukemia K562 cells by inhibiting the miRNA-21 expression to explore its pathogenesis of leukemia. Methods: The chemical synthetic miRNA-21 inhibitor was transfered into K562 cells by electrotransfection. RT-PCR was used to detect the miRNA-21 expression changes. Cell proliferation and apoptosis were determined by using MTT and flow cytometry. Western-blot were used to detect the protein expression changes of PTEN, PI3K and p-AKT respectively. Results: The relative expression of miRNA-21 in experimental group was (8.070 ± 5.138)% at 24 hours, which was lower than control groups (P<0.05). The apoptotic rate of (13.370±0.250)% at 24 hours in experimental group was obviously higher than control groups. The cellular proliferation were significantly different at 24 hours. The proliferation inhibition rate was (8.1±0.9)% at 24 hours, which was up to (43.1±2.1)% at 60 hours, but the control groups showed no difference. K562 cell proliferation significantly decreased, while cell apoptosis markedly increased by inhibiting miRNA-21 expression (P<0.01). Western-blot analysis revealed up-regulation of PTEN and down-regulation of PI3K and p-AKT protein expressions after successfully suppressed miRNA-21 expression (P<0.01). Conclusion: Inhibiting miRNA-21 expression in K562 cell could suppress the PI3K/AKT pathway by up-regulation of PTEN expression and promote cell antiproliferative and pro-apoptosis effects.
目的: 研究靶向抑制miRNA-21表达对K562细胞生物学功能的影响，观察其对PTEN-PI3K/AKT通路相关分子表达水平的影响，探讨其在白血病发病机制中的作用。
方法: 将化学合成的miRNA-21抑制物电转染K562细胞，RT-PCR检测K562细胞miRNA-21表达变化，MTT法检测miRNA-21对K562细胞活力影响，流式细胞术分析miRNA-21对K562细胞凋亡的影响，应用Western blot技术检测K562细胞中PTEN、PI3K及p-AKT蛋白表达水平。
结果: 转染24 h实验组miRNA-21 mRNA相对表达水平为（8.070±5.138）%，低于各对照组（P <0.05）。转染24 h实验组K562细胞凋亡率为（13.370±0.250）%，高于各对照组（P<0.01）。实验组K562细胞的增殖抑制率由转染后24 h的（8.1± 0.9）％升至60 h的（43.1±2.1）%。成功抑制miRNA-21表达后，与对照组相比，K562细胞凋亡增加（P< 0.01），细胞中PTEN蛋白表达上调（P<0.01），PI3K及p-AKT蛋白表达下调（P<0.01）。
结论: 靶向抑制K562细胞miRNA-21可以上调PTEN表达而抑制PI3K/AKT信号通路，发挥其抑制K562细胞增殖及促进凋亡作用。