Department of General Thoracic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, P.R. China.
Mol Med Rep. 2011 Sep-Oct;4(5):1007-15. doi: 10.3892/mmr.2011.530. Epub 2011 Jul 1.
Transforming growth factor β (TGF-β) is overexpressed in a wide variety of cancer types including lung adenocarcinoma (LAC), and the TGF-β signaling pathway plays an important role in tumor development. To determine whether blockade of the TGF-β signaling pathway can inhibit the malignant biological behavior of LAC, RNA interference (RNAi) technology was used to silence the expression of TGF-β receptor, type II (TGFβRII) in the LAC cell line, A549, and its effects on cell proliferation, invasion and metastasis were examined. Three specific small interfering RNAs (siRNAs) designed for targeting human TGFβRII were transfected into A549 cells. The expression of TGFβRII was detected by Western blot analysis. Cell proliferation was measured by MTT and clonogenic assays. Cell apoptosis was assessed by flow cytometry. The invasion and metastasis of A549 cells were investigated using the wound healing and Matrigel invasion assays. The expression of PI3K, phosphorylated Smad2, Smad4, Akt, Erk1/2, P38 and MMPs was detected by Western blot analysis. The TGFβRII siRNA significantly reduced the expression of TGFβRII in A549 cells. The knockdown of TGFβRII in A549 cells resulted in the suppression of cell proliferation, invasion and metastasis and induced cell apoptosis. In addition to the Smad-dependent pathway, independent pathways including the Erk MAPK, PI3K/Akt and p38 MAPK pathways, as well as the expression of MMPs and VEGF, were inhibited. In conclusion, TGF-β signaling is required for LAC progression. Therefore, the blockade of this signaling pathway by the down-regulation of TGFβRII using SiRNA may provide a potential gene therapy for LAC.
转化生长因子 β（TGF-β）在多种癌症类型中过度表达，包括肺腺癌（LAC），TGF-β 信号通路在肿瘤发展中起着重要作用。为了确定阻断 TGF-β信号通路是否能抑制 LAC 的恶性生物学行为，本研究采用 RNA 干扰（RNAi）技术沉默 LAC 细胞系 A549 中 TGF-β 受体 II 型（TGFβRII）的表达，并检测其对细胞增殖、侵袭和转移的影响。设计了针对人 TGFβRII 的三个特定的小干扰 RNA（siRNA）转染到 A549 细胞中。通过 Western blot 分析检测 TGFβRII 的表达。通过 MTT 和集落形成实验检测细胞增殖。通过流式细胞术评估细胞凋亡。通过划痕愈合和 Matrigel 侵袭实验研究 A549 细胞的侵袭和转移。通过 Western blot 分析检测 PI3K、磷酸化 Smad2、Smad4、Akt、Erk1/2、P38 和 MMPs 的表达。TGFβRII siRNA 显著降低了 A549 细胞中 TGFβRII 的表达。在 A549 细胞中敲低 TGFβRII 导致细胞增殖、侵袭和转移受到抑制，并诱导细胞凋亡。除了 Smad 依赖性途径外，还抑制了包括 Erk MAPK、PI3K/Akt 和 p38 MAPK 途径以及 MMPs 和 VEGF 的表达。总之，TGF-β信号通路对于 LAC 的进展是必需的。因此，通过下调 TGFβRII 使用 SiRNA 阻断这种信号通路可能为 LAC 提供一种潜在的基因治疗方法。
