AIM: To investigate the relationship of microRNA-7 ( miRNA-7 ) over-expression and epidermal growth factor receptor (EGFR)/phosphatidylinositol kinase-3 (PI3K)/protein kinase B (PKB, also called Akt) pathway in human nasopharyngeal carcinoma 5-8F cells.METHODS:The 5-8F cells were transfected with miRNA-7 mimics (car-rying by Lipofectamine 2000).The expression of miRNA-7 was detected by real-time PCR.The cell proliferation was ana-lyzed by CCK-8 assay.The cell colony-forming capability was determined by cell colony formation test.The expression of EGFR/PI3K/Akt at mRNA and protein levels was examined by real-time PCR and Western blotting.RESULTS:The ex-pression level of miRNA-7 was significantly increased in 5-8F cells compared with negative control ( NC) group and control group ( P<0.01) .The proliferation of NPC 5-8F cells was decreased extremely after tansfected with the miRNA-7 mimics (P<0.01), so did the result of the cell colony-formation test.The expression of EGFR/PI3K/Akt at mRNA and protein levels was significantly down-regulated compared with NC group and control group (P<0.01).CONCLUSION:Over-ex-pression of miRNA-7 significantly inhibits the proliferation and colony-forming ability of nasopharyngeal carcinoma 5-8F cells by down-regulation of EGFR/PI3K/Akt pathway.%目的：探讨过表达微小RNA（microRNA-7，miRNA-7）对鼻咽癌（nasopharyngeal carcinoma，NPC）5-8F细胞增殖能力的抑制作用及其与表皮生长因子受体（epidermal growth factor receptor，EGFR）/磷脂酰肌醇3-激酶（ phosphatidylinositol 3-kinase，PI3K）/蛋白激酶B（ protein kinase B，PKB，也称Akt）通路的关联情况。方法：利用脂质体试剂Lipofectamine 2000将miRNA-7模拟物转染入人鼻咽癌5-8F细胞中；采用real-time PCR法检测转染后各组细胞中miRNA-7的表达情况；CCK-8法检测细胞增殖能力变化；细胞平板克隆形成实验观察转染后细胞克隆能力变化情况；real-time PCR法检测EGFR/PI3K/Akt通路各mRNA表达水平的变化；Western blotting法检测EGFR/PI3K/AKT通路各蛋白表达水平的变化。结果：real-time PCR结果显示，转染miRNA-7模拟物组细胞中的miRNA-7表达水平显著高于无关序列组和空白对照组（P＜0．01）；5-8F细胞转染miRNA-7模拟物后，细胞增殖和平板克隆能力均呈明显下降（P＜0．01）；real-time PCR及Western blotting结果显示，转染组的5-8F细胞中EGFR/PI3K/Akt通路中各主要成员的mRNA及相应蛋白表达水平均有明显降低（P＜0．01）。结论：过表达miRNA-7可以显著降低鼻咽癌5-8F细胞中EGFR/PI3K/Akt通路各主要成员mRNA和蛋白的表达水平，进而显著抑制其增殖和平板克隆形成能力。
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