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目的:探讨前B淋巴细胞白血病转录因子(PBX1)基因表达对肺癌细胞凋亡、ROS含量和STAT3信号通路的影响。方法:采用实时荧光定量聚合酶链反应检测肺癌及癌旁组织中PBX1基因的表达水平，分析PBX1基因表达水平与患者临床病理特征的关系。采用Western blot法检测人肺癌A549、SPC-A1、SK-MES-1和H1299细胞株中PBX1蛋白的表达水平。应用脂质体法转染空白对照(空白组)、阴性对照(阴性组)和PBX1小干扰RNA(siPBX1组)至A549细胞，采用流式细胞术检测各组细胞的凋亡率和ROS含量，采用Western blot检测各组细胞中PBX1、STAT3、磷酸化STAT3(p-STAT3)、Bcl-2和survivin蛋白的表达水平。结果:肺癌组织中PBX1信使RNA的表达水平(2.36±0.23)高于癌旁组织(1.02±0.15)，差异有统计学意义( P<0.05)。PBX1基因表达水平与肺癌分化程度、淋巴结转移和TNM分期均有关(均 P<0.05)。PBX1蛋白在人肺癌A549、SPC-A1、SK-MES-1和H1299细胞中的表达水平分别为0.454±0.038、0.403±0.034、0.311±0.028和0.377±0.035，与人正常肺MRC-5细胞(0.041±0.007)比较，差异均有统计学意义(均 P<0.05)。转染PBX1 siRNA的A549细胞中，PBX1蛋白的表达水平(0.082±0.010)低于空白组(0.704±0.065)，差异有统计学意义( P<0.05)。siPBX1组细胞的凋亡率和ROS含量分别为(30.78±3.64)%和51.55±5.03，与空白组[分别为(3.92±0.27)%和22.36±1.31]比较，差异均有统计学意义(均 P<0.05)。p-STAT3、Bcl-2和survivin蛋白的表达水平分别为0.051±0.006、0.202±0.018和0.068±0.008，与空白组(分别为0.172±0.010、0.425±0.041和0.196±0.021)比较，差异均有统计学意义(均 P<0.05)。 结论:抑制PBX1基因的表达可诱导肺癌细胞凋亡，其机制可能与ROS产生和STAT3信号的下调有关。

Objective:To investigate the effects of pre-B lymphocytic leukemia transcription factor (PBX1) expression on the apoptosis, reactive oxygen species (ROS) content and transcriptional activation factor 3 (STAT3) signaling pathway of lung cancer cells.Methods:Real-time quantitative polymerase chain reaction was used to detect the expression level of PBX1 in lung cancer tissues and adjacent tissues. The correlation between PBX1 expression level and clinical pathological parameters of patients were analyzed. Western blot was used to detect the protein expression level of PBX1 in human lung cancer cell lines, including A549, SPC-A1, SK-MES-1 and H1299. A549 cells were transfected with blank control (blank group), negative control (NC group) or PBX1 small interfering RNA (siRNA group), respectively. The cells apoptosis and ROS content were detected by flow cytometry. The protein expression levels of PBX1, STAT3, phosphorylated STAT3 (p-STAT3), B cell lymphoma/leukemia-2 (Bcl-2) and survivin in each group were detected by western blot.Results:The expression level of PBX1 mRNA in lung cancer was (2.36±0.23), significantly higher than (1.02±0.15) in paracancerous tissues ( P<0.05). The expression level of PBX1 was correlated with lung cancer differentiation, lymph node metastasis and TNM stage ( P<0.05). The expression levels of PBX1 in human lung cancer cells A549, SPC-A1, SK-MES-1 and H1299 were (0.454±0.038), (0.403±0.034), (0.311±0.028) and (0.377±0.035), respectively, significantly higher than (0.041±0.007) of human normal lung cells MRC-5 ( P<0.05). The expression level of PBX1 protein in A549 cells transfected with PBX1 siRNA was (0.082±0.010), significantly lower than (0.704±0.065) of the blank group ( P<0.05). The apoptosis rate and ROS content of siPBX1 group were (30.78±3.64)% and (51.55±5.03), respectively, significantly higher than (3.92±0.27)% and (22.36±1.31) of blank group ( P<0.05). The protein expressions of p-STAT3, Bcl-2 and survivin were (0.051±0.006), (0.202±0.018) and (0.068±0.008), respectively, significantly lower than (0.172±0.010), (0.425±0.041) and (0.196±0.021) of blank group ( P<0.05). Conclusion:Inhibition of PBX1 expression can induce the apoptosis of lung cancer cell, the mechanism may be related to ROS production and down-regulation of STAT3 signal.