Smad2基因在肺癌组织和细胞中的表达特点

Expression Characteristics of Smad2 Gene in Lung Cancer Tissues and Cells

目的探讨Smad2基因在肺癌组织和细胞中的表达特点.方法分析Smad2的mRNA和蛋白在肺癌组织和癌旁正常组织中的表达情况;收集患者的临床病理指标,并进行5 a随访,记录患者生存情况,分析与Smad2基因表达的关系.培养人正常肺上皮细胞BEAS-2B、人肺癌细胞A549,检测Smad2的mRNA和蛋白表达水平;使用10μg/L的3-甲基胆蒽连续染毒培养至第10代、第20代、第30代、第40代,检测Smad2基因表达变化;使用Smad2过表达质粒、Anti-Smad2质粒分别转染A549细胞,比较细胞增殖、迁移和侵袭能力.结果肺癌组织中Smad2的mRNA和蛋白表达水平明显高于癌旁正常组织(P<0.01).人肺癌细胞A549中Smad2的mRNA和蛋白表达水平明显高于人正常肺上皮细胞BEAS-2B(P<0.05).随着3-甲基胆蒽诱导人正常肺上皮细胞BEAS-2B恶性转化传代数的增加,Smad2的mRNA和蛋白表达水平逐渐降低(P<0.05).N2~N3期的肺癌患者Smad2基因低表达率明显高于N0~N1期的患者,肿瘤分期Ⅲ~Ⅳ期的肺癌患者Smad2基因低表达率明显高于Ⅰ~Ⅱ期的患者(P<0.01).Smad2基因低表达肺癌患者术后生存时间、3 a生存率、5 a生存率均明显短于Smad2基因过表达患者(P<0.01).Smad2过表达组人肺癌细胞A549增殖能力、迁移细胞数、侵袭细胞数明显低于对照组,Smad2低表达组细胞增殖能力、迁移细胞数、侵袭细胞数明显高于对照组和Smad2过表达组(P<0.01).结论Smad2基因在肺癌组织和细胞中表达下调,可提升肺癌细胞的增殖、迁移和侵袭能力,进而参与肺上皮细胞癌变过程,且与患者肿瘤分期和术后生存时间密切相关.

ObjectiveTo investigate the expression characteristics of Smad2 gene in lung cancer tissues and cells.MethodThe expression of Smad2 mRNA and protein in lung cancer and adjacent normal tissues were analyzed;The clinic pathological indexes of patients were collected,followed up for 5 years,the survival was recorded,and the relationship with Smad2 gene expression was analyzed.Human normal lung epithelial cell BEAS-2B and human lung cancer cell A549 were cultured,and the expression levels of Smad2 mRNA and protein were detected;Use 10μG/L 3-methylcholanthrene was continuously exposed and cultured to the 10th,20th,30th and 40th generations,and the expression of Smad2 gene was detected;A549 cells were transfected with Smad2 overexpression plasmid and Anti-Smad2 plasmid respectively.ResultsThe expression levels of Smad2 mRNA and protein in lung cancer tissues were significantly higher than those in adjacent normal tissues(P<0.01).The expression levels of Smad2 mRNA and protein in human lung cancer cell A549 were significantly higher than those in human normal lung epithelial cell BEAS-2B(P<0.05).The expression levels of Smad2 mRNA and protein decreased gradually with the increase of transmission generation of BEAS-2B malignant transformation induced by 3-methylcholanthrene(P<0.05).The low expression rate of Smad2 gene in patients with N2~N3 stage lung cancer was significantly higher than that in patients with N0~N1 stage.The low expression rate of Smad2 gene in patients with tumor stageⅢ~Ⅳwas significantly higher than that in patients with stageⅠ~Ⅱ(P<0.01).The postoperative survival time,3-year survival rate and 5-year survival rate of lung cancer patients with low Smad2 gene expression were significantly shorter than those with high Smad2 gene expression(P<0.01).The proliferation ability,the number of migrating cells and the number of invasive cells of human lung cancer cell A549 in Smad2 overexpression group were significantly lower than those in the control group.The proliferation ability,the number of migrating cells and the number of invasive cells in Smad2 low expression group were significantly higher than those in the control group and Smad2 overexpression group(P<0.01).ConclusionThe down-regulation of Smad2 gene expression in lung cancer tissues and lung cancer cells can improve the proliferation,migration and invasion of lung cancer cells,participate in the carcinogenesis of lung epithelial cells,and is closely related to tumor stage and postoperative survival time.