Institute of Digestive Endoscopy and Medical Center for Digestive Diseases, Second Affiliated Hospital of Nanjing Medical University, Nanjing 210011, P.R. China.
Mol Med Rep. 2010 Mar-Apr;3(2):295-9. doi: 10.3892/mmr_00000254.
Hepatocellular carcinoma (HCC) is a highly malignant cancer characterized by rapid progression, easy metastasis and frequent recurrence. Previous studies have shown that the Smad4 signaling pathway plays an important role in the cell growth and apoptosis of HCC. However, the effect of Smad4 signaling on the invasion and migration of HCC cells remains unclear. The present study aimed to examine the effects of the transforming growth factor (TGF)-β1-Smad4 signaling pathway on the migration of HCC cells. Lentiviral vectors expressing miRNA against Smad4 were constructed to block the expression of Smad4 in HCC cells, and transwell units were used to investigate the invasive potential of SMMC-7721 cells before and after TGF-β1 treatment. mRNA levels of matrix metalloproteinase (MMP)-2 and -9 were analyzed by reverse-transcription PCR, and concentrations of vascular endothelial growth factor (VEGF), p-JNK, p-p38 and p-Erk1/2 proteins were analyzed by Western blotting. The results indicate that TGF-β1 induced cellular invasion in the SMMC-7721 cells. These effects were almost completely blocked by the knockdown of Smad4. Reverse-transcription PCR and Western blot analysis revealed that MMP-2, VEGF, p-JNK and p-p38 were up-regulated by the silencing of Smad4, while the expression of MMP-9 and p-Erk1/2 was not affected by Smad4 silencing with or without TGF-β1 stimulation. These findings suggest that TGF-β1-induced SMMC-7721 cell invasion by the up-regulation of MMP-2 and VEGF is Smad4-dependent. The activation of MMP-2 and VEGF may be an important mechanism by which Smad4 is involved in metastasis. TGF-β1-Smad4 signaling may regulate SMMC-7721 cell migration through the activation of the MAPK pathway.
肝细胞癌（HCC）是一种高度恶性癌症，其特征为进展迅速、易转移和频繁复发。先前的研究表明，Smad4 信号通路在 HCC 细胞的生长和凋亡中发挥重要作用。然而，Smad4 信号对 HCC 细胞侵袭和迁移的影响尚不清楚。本研究旨在探讨转化生长因子（TGF）-β1-Smad4 信号通路对 HCC 细胞迁移的影响。构建了表达针对 Smad4 的 miRNA 的慢病毒载体以阻断 HCC 细胞中 Smad4 的表达，并使用 Transwell 小室检测 TGF-β1 处理前后 SMMC-7721 细胞的侵袭潜力。通过逆转录 PCR 分析基质金属蛋白酶（MMP）-2 和 -9 的 mRNA 水平，并通过 Western blot 分析血管内皮生长因子（VEGF）、p-JNK、p-p38 和 p-Erk1/2 蛋白的浓度。结果表明，TGF-β1 诱导 SMMC-7721 细胞发生细胞侵袭。这些作用几乎完全被 Smad4 的敲低所阻断。逆转录 PCR 和 Western blot 分析显示，MMP-2、VEGF、p-JNK 和 p-p38 被 Smad4 的沉默上调，而 MMP-9 和 p-Erk1/2 的表达不受 Smad4 沉默的影响，无论是否有 TGF-β1 刺激。这些发现表明，TGF-β1 通过上调 MMP-2 和 VEGF 诱导 SMMC-7721 细胞侵袭依赖于 Smad4。MMP-2 和 VEGF 的激活可能是 Smad4 参与转移的重要机制。TGF-β1-Smad4 信号可能通过激活 MAPK 通路来调节 SMMC-7721 细胞迁移。
