Department of Respiratory Medicine, The Second Hospital of Shandong University, 247 Beiyuan Street, Jinan, Shandong 250033 China.
Cell Mol Biol Lett. 2017 Nov 2;22:22. doi: 10.1186/s11658-017-0053-1. eCollection 2017.
TGF-β1 plays an important role in the epithelial-mesenchymal transition (EMT) of epithelial cancers, including non-small cell lung cancer (NSCLC). While the full underlying mechanism remains unclear, miR-9 is known to play a critical role in the regulation of NSCLC cell invasion. We tested whether miR-9 targets E-cadherin and thus affects TGF-β1-induced EMT in NSCLC cells by assessing the expression levels of miR-9 and E-cadherin for NSCLC patients and then verifying the targeting of E-cadherin by miR-9 using the dual luciferase reporter system.
MiR-9 was significantly upregulated in NSCLC tissues compared with its level in adjacent normal tissues. The expression of E-cadherin in NSCLC tissues was significantly decreased. In addition, we found that TGF-β1 significantly upregulated the expression of miR-9 and downregulated the expression of E-cadherin. E-cadherin was confirmed as a direct target gene of miR-9. Using an miR-9 inhibitor reversed the TGF-β1-mediated inhibition of E-cadherin expression and upregulation of the mesenchymal marker α-SMA. TGF-β1 significantly induced cell invasion, and this effect was significantly inhibited by miR-9 inhibitors.
TGF-β1 induced EMT in NSCLC cells by upregulating miR-9 and downregulating miR-9's target, E-cadherin.
TGF-β1 在包括非小细胞肺癌(NSCLC)在内的上皮性癌的上皮-间充质转化(EMT)中发挥重要作用。虽然其潜在的完整机制尚不清楚,但 miR-9 已知在调节 NSCLC 细胞侵袭中发挥关键作用。我们通过评估 NSCLC 患者 miR-9 和 E-cadherin 的表达水平,测试了 miR-9 是否通过靶向 E-cadherin 从而影响 NSCLC 细胞中的 TGF-β1 诱导的 EMT,并使用双荧光素酶报告系统验证了 miR-9 对 E-cadherin 的靶向作用。
与相邻正常组织相比,miR-9 在 NSCLC 组织中明显上调。NSCLC 组织中 E-cadherin 的表达明显下调。此外,我们发现 TGF-β1 可显著上调 miR-9 的表达并下调 E-cadherin 的表达。E-cadherin 被确认为 miR-9 的直接靶基因。使用 miR-9 抑制剂可逆转 TGF-β1 介导的 E-cadherin 表达抑制和间充质标记物α-SMA 的上调。TGF-β1 可显著诱导细胞侵袭,而 miR-9 抑制剂可显著抑制这种作用。
TGF-β1 通过上调 miR-9 并下调 miR-9 的靶基因 E-cadherin,诱导 NSCLC 细胞发生 EMT。