Department of Hepatic Surgery, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai, China.
PLoS One. 2012;7(6):e39668. doi: 10.1371/journal.pone.0039668. Epub 2012 Jun 27.
Krüppel-like factor 8 (KLF8) plays important role in cell cycle and oncogenic transformation. Here we report the mechanisms by which KLF8 crosstalks with Wnt/β-catenin signaling pathway and regulates hepatocellular carcinoma (HCC) cells proliferation. We show that overexpression of KLF8 and nucleus accumulation of β-catenin in the human HCC samples are positively correlated. More importantly, KLF8 protein levels plus nucleus accumulation of β-catenin levels were significantly elevated in high-grade HCC compared to low-grade HCC. Using HCC HepG2 cells we find that, on the one hand both protein and mRNA of KLF8 are up-regulated under Wnt3a stimulation, on the other hand overexpression of KLF8 increases the cytoplasm and nucleus accumulation of β-catenin, recruits p300 to β-catenin/T-cell factor 4 (TCF4) transcription complex, enhances TOP flash report gene transcription, and induces Wnt/β-catenin signaling target genes c-Myc, cyclin D1 and Axin1 expression. Knockdown of KLF8 using shRNA inhibits Wnt3a induced transcription of TOP flash report gene and expression of c-Myc, cyclin D1 and Axin1. Knockdown of β-catenin by shRNA rescues the enhanced HepG2 and Hep3B cells proliferation ability induced by overexpression of KLF8.
Krüppel 样因子 8（KLF8）在细胞周期和致癌转化中发挥重要作用。在这里，我们报告了 KLF8 与 Wnt/β-连环蛋白信号通路相互作用并调节肝细胞癌（HCC）细胞增殖的机制。我们发现，KLF8 的过表达和β-连环蛋白在人 HCC 样本中的核积累呈正相关。更重要的是，与低级别 HCC 相比，高级别 HCC 中 KLF8 蛋白水平和β-连环蛋白核积累水平显著升高。使用 HCC HepG2 细胞，我们发现一方面，Wnt3a 刺激下 KLF8 的蛋白和 mRNA 均上调，另一方面，KLF8 的过表达增加了β-连环蛋白的细胞质和核积累，募集 p300 到β-连环蛋白/T 细胞因子 4（TCF4）转录复合物，增强 TOP flash 报告基因转录，并诱导 Wnt/β-连环蛋白信号靶基因 c-Myc、cyclin D1 和 Axin1 的表达。使用 shRNA 敲低 KLF8 抑制了 Wnt3a 诱导的 TOP flash 报告基因转录和 c-Myc、cyclin D1 和 Axin1 的表达。用 shRNA 敲低β-连环蛋白可挽救 KLF8 过表达诱导的 HepG2 和 Hep3B 细胞增殖能力增强。
