STC1基因对A549细胞放射敏感性影响

The effect of STC1 gene on radiosensitivity of human lung cancer A549 cell line

目的探讨斯钙素-1(STC1)基因对人肺癌A549细胞增殖凋亡及放射敏感性影响。方法将合成的STC1-siRNA及不具有干扰作用的siRNA(阴性对照组)经Lipofectamine^TM2000转染人肺癌A549细胞,并设置空白组,通过Western blotting检测转染48h后各组细胞STC1的蛋白表达。用克隆形成实验检测A549细胞经STC1-siRNA和照射处理后的增殖情况,用CCK8法检测细胞经STC1-siRNA和STC1-siRNA+8Gy处理后的活力,用流式细胞仪检测细胞凋亡率。用Western blotting检测ki67、Bcl-2相关X蛋白(Bax)、STAT3和磷酸化的信号转导与转录因子3(p-STAT3)的蛋白表达。结果STC1-siRNA转染的A549细胞STC1的蛋白表达低于空白组(P<0.05)。与单纯照射组比较,转染STC1-siRNA后的增敏比明显升高。与空白组比较,STC1-siRNA组细胞活力及ki67和p-STAT3的蛋白表达均降低,细胞凋亡率和Bax蛋白表达均升高;与STC1-siRNA组比较,STC1-siRNA+8Gy组细胞活力及ki67和p-STAT3蛋白表达均降低,细胞凋亡率和Bax蛋白表达均升高(P<0.05)。结论抑制STC1基因表达可增强非小细胞肺癌的放射敏感性并下调STAT3信号通路。

Objective To investigate effect of stanniocalcin-1(STC1) gene on the proliferation,apoptosis and radiotherapy sensitivity of non-small cell lung cancer.Methods The STC1 siRNA (STC1-siRNA) and the non-interfering siRNA (negative control group) were transfected into the human lung cancer A549 cells by Lipofectamine^TM2000,and the blank control group was established.The expression level of STC1 protein was detected after transfection for 48 h by Western blotting.Clone forming test was adopted to detect the proliferation of A549 cells after STC1-siRNA and irradiation treatment.CCK8 assay was performed to detect the cell viability after treatment with STC1-siRNA and STC1-siRNA+8 Gy.The cell apoptosis was detected by flow cytometry.The expression levels of Ki67,Bax,STAT3 and p-STAT3 proteins were quantitatively measured by Western blotting.Results The expression level of STC1 protein in the A549 cells transfected with STC1-siRNA was significantly down-regulated than that in the blank control group (P<0.05).Compared with the blank control group,the sensitization ratio was significantly enhanced after STC1-siRNA transfection.Compared with the blank control group,the cell viability and the expression levels of Ki67 and p-STAT3 protein were significantly decreased,whereas the apoptosis rate and the expression of Bax protein were significantly increased in the STC1-siRNA group.Compared with the STC1-siRNA group,the cell viability and the expression levels of Ki67 and p-STAT3 proteins were significantly decreased,whereas the cell apoptosis rate and the expression of Bax protein were remarkably increased in the STC1-siRNA+8 Gy group (all P<0.05).Conclusion Inhibition of STC1 gene expression can enhance the radiotherapy sensitivity and down-regulate the STAT3 signaling pathway in non-small cell lung cancer.