烯醇化酶ENO1抑制非小细胞肺癌细胞上皮间质转换

α-Enolase(ENO1) Inhibits Epithelial-mesenchymal Transition in the A549 Cell Line by Suppressing ERK1/2 Phosphorylation

背景与目的已有的研究表明:上皮间质转换(epithelial-mesenchymal transition,EMT)是非小细胞肺癌发展和转移的一个重要过程,受到众多信号通路的精细调节。经典的丝裂原活化激酶(mitogen activatedprotein kinase,MAPK)信号通路是转化生长因子(transforming growth factor β,TGFβ)诱导EMT发生的必要条件。本研究以非小细胞肺癌细胞系A549为模型,对烯醇化酶(enolase-1,ENO1)影响细胞EMT过程的分子机制进行了初步研究。方法建立稳定过表达ENO1的A549细胞,用划痕实验检测细胞运动能力;用Western blot技术检测EMT过程相关分子标志物的变化;通过TGFβ-1诱导实验检测ENO1过表达对EMT的影响;通过上皮生长因子(epidermal growth factor,EGF)诱导实验和Western blot检测ENO1过表达引起胞外信号调节激酶(extracellular signal regulated protein kinase,ERK)磷酸化的改变。结果 ENO1过表达抑制A549细胞侧向迁移能力。ENO1过表达还会引起上皮样标志物E-cad-herin表达上调,同时间质样标志物N-cadherin和Vimentin表达下降;TGFβ-1诱导实验也证实了ENO1对EMT进程的抑制作用。EGF活化实验显示ENO1对ERK磷酸化的抑制作用。结论在非小细胞肺癌细胞中,ENO1具有抑制细胞EMT的作用,且很可能是通过抑制MAPK通路来实现。

Background and objective It has been proven that epithelial-mesenchymal transition （EMT） is a critical process which is precisely regulated by multiple signaling pathways during the progression and metastasis of non-small cell lung cancer （NSCLC）. Canonical MAPK signaling is essential to transforming growth factor β（TGFβ）-induced EMT. Using the NSCLC cell line A549 as a model, the aim of this study is to explore the molecular mechanism of ENO 1 affecting EMT. Methods We established an A549 strain stably overexpressing ENO 1. Cell mobility was measured by the wound-healing assay. EMT-related molecular alterations were detected by Western blot analysis. The effect of ENO 1 on EMT was also detected by TGFβ-1-inducing assay. EGF-stimulating assay was performed to illustrate ERK1/2 phosphorylation changes resulting from ENO1 overexpression. Results Overexpressed ENO1 inhibited the mobility ofA549 （P〈0.05）, as well as the expression of the mesenchymal markers N-cadherin and vimentin, but upregulated the epithelial marker E-cadherin. TGFβ-inducing assay also showed that the negative effect of ENO I on EMT. ERK1/2 phosphorylation was also obviously suppressed by ENO 1 in the EGF-stimulating assay. Conclusion In NSCLC cells, ENO1 overexpression can inhibit EMT in vitro by suppressing ERK1/2 phosphorylation.