Runx2在TGF-β1诱导的肺癌A549细胞上皮-间质转化过程中的作用研究

The effects of Runx2 on TGF-β1-induced epithelial-mesenchymal transition in lung cancer A549 cells

背景与目的:转化生长因子-β(transforming growth factor-β,TGF-β)通路与肿瘤细胞上皮-间质转化(epithelialmesenchymal transition,EMT)过程有着密切的联系,而Runx2蛋白是TGF-β通路中重要的组成部分,与肿瘤的转移过程密切相关。探讨Runx2蛋白在TGF-β1诱导的肺癌A549细胞EMT过程中的作用。方法:利用TGF-β1诱导A549细胞(由天津医科大学附属肿瘤医院惠赠),建立EMT模型,通过利用RNA干扰及转染技术降低Runx2表达,研究其对肿瘤细胞EMT的影响,利用LY294002和PD98059分别阻断磷酸肌醇3激酶/蛋白激酶B(phosphatidylinositide3-kinases/protein kinase B,PI3K/AKT)和丝裂原活化蛋白激酶/细胞外信号调节激酶(mitogen-activated protein kinase/extracellular signal-regulated kinase,MAPK/ERK)通路研究Runx2作用的机制。结果:5 ng/mL TGF-β1 72 h可以诱导肺癌A549细胞发生明显的EMT,干扰Runx2的表达可以阻止TGF-β1诱导的肿瘤细胞发生EMT。在EMT过程中,TGF-Smad2通路及旁路PI3K/AKT和MAPK/ERK通路发生激活。通路实验显示,Runx2表达在PI3K/AKT通路阻断后明显降低。结论:Runx2在TGF-β1诱导的肿瘤细胞EMT过程中发挥着必要作用,而且TGF-β1主要是通过P13K/AKT通路调控Runx2的表达促进细胞发生EMT。

Background and purpose:Transforming growth factor-β(TGF-β)signaling has been shown to play an important role in epithelial-mesenchymal transition(EMT).Furthermore,Runx2 plays an important role in the progress of tumor metastasis and is also regulated by TGF-βsignaling.This study was designed to investigate the induction of EMT in response to TGF-βand the role of Runx2 in this process.Methods:A549 cells(donated by Tianjin Medical University Cancer Institute and Hospital)were induced by TGF-β1 to build the EMT model.The cells were infected with siRNA to downregulate the expression of Runx2.Phosphatidylinositide 3-kinases/protein kinase B(PI3K/AKT)and mitogen-activated protein kinase/extracellular signal-regulated kinase(MAPK/ERK)pathway were blocked by specific inhibitor LY294002 and PD98059 to explore the mechanism.Results:The EMT model was induced by 5 ng/mL TGF-β1 for 72 h.At the same time,downregulation of Runx2 with siRNA could prevent cancer cell from the progress of EMT.In addition,the results showed PI3K/AKT-MAPK/ERK and TGF-βsignaling pathways were both activated in this process,and the expression of Runx2 was significantly decreased after blocking PI3K/AKT pathway,compared with the MAPK/ERK pathway.Conclusion:TGF-β1 regulates Runx2 to affect the progression of EMT mainly by the PI3K/AKT pathway,and Runx2 plays a necessary role in the process of tumor cell EMT.