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 ENO1 affecting EMT.
Methods: We established an A549 strain stably overexpressing ENO1. Cell mobility was measured by the wound-healing assay. EMT-related molecular alterations were detected by Western blot analysis. The effect of ENO1 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 of A549 (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 ENO1 on EMT. ERK1/2 phosphorylation was also obviously suppressed by ENO1 in the EGF-stimulating assay.
Conclusions: In NSCLC cells, ENO1 overexpression can inhibit EMT in vitro 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 activated protein 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-cadherin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。