Park Na Ri, Cha Jung Hoon, Jang Jeong Won, Bae Si Hyun, Jang Bohyun, Kim Jung-Hee, Hur Wonhee, Choi Jong Young, Yoon Seung Kew
The Catholic University Liver Research Center & WHO Collaborating Center of Viral Hepatitis, The Catholic University of Korea, Seoul, Republic of Korea.
The Catholic University Liver Research Center & WHO Collaborating Center of Viral Hepatitis, The Catholic University of Korea, Seoul, Republic of Korea; Department of Internal Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Republic of Korea.
Biochem Biophys Res Commun. 2016 Sep 2;477(4):568-574. doi: 10.1016/j.bbrc.2016.06.077. Epub 2016 Jun 16.
Cancer metastasis is strongly correlated with epithelial-mesenchymal transition (EMT), in which transforming growth factor-β (TGF-β) signaling plays a central role. CD44 has emerged as a cancer stem cell (CSC) marker that strongly induces EMT together with TGF-β1. This study aimed to investigate the link between high CD44 and TGF-β1 levels during EMT in HCC cell lines. FACS analysis showed high expression of CD44 in TGF-β1-positive SNU-368 cells and TGF-β1-negative SNU-354 cells. SNU-368 CD44(+) cells showed EMT through up-regulation of the AKT/GSK-3β/β-catenin pathway. By comparison, SNU-354 CD44(+) cells showed only increased N-cadherin expression, which was not accompanied by a decrease in E-cadherin expression, and also down-regulated the AKT/GSK-3β/β-catenin pathway. However, TGF-β1-stimulated SNU-354 cells (CD44/TGF-β1(+)) exhibited lower E-cadherin and higher N-cadherin expression with increased AKT/GSK-3β/β-catenin pathway activity. CD44/TGF-β1(+) SNU-354 cells also showed enhanced migration and formed larger spheres, while the TGF-β1-induced stem cell properties returned to their original state with the TGF-β1 inhibitor SB431542. SB431542-treated SNU-368 (CD44/TGF-β1(-)) cells also showed diminished N-cadherin and AKT/GSK-3β/β-catenin pathway activity and further decreased cell motility in a wound healing assay. However, CD44 knockdown in SNU-354 cells did not induce EMT even after treatment with TGF-β1. Finally, double inhibition of both CD44 and TGF-β1 further decreased migration and sphere formation more strongly than a single inhibition in SNU-368 cells. In conclusion, the current study demonstrated the synergistic interactions between CD44 and TGF-β1 in EMT induction and CSC properties through the AKT/GSK-3β/β-catenin pathway in HCC cells.
癌症转移与上皮-间质转化（EMT）密切相关，其中转化生长因子-β（TGF-β）信号传导起着核心作用。CD44已成为一种癌症干细胞（CSC）标志物，它与TGF-β1一起强烈诱导EMT。本研究旨在探讨肝癌细胞系EMT过程中高CD44水平与TGF-β1水平之间的联系。流式细胞术分析显示，在TGF-β1阳性的SNU-368细胞和TGF-β1阴性的SNU-354细胞中CD44均高表达。SNU-368 CD44(+)细胞通过上调AKT/GSK-3β/β-连环蛋白通路表现出EMT。相比之下，SNU-354 CD44(+)细胞仅表现出N-钙黏蛋白表达增加，而E-钙黏蛋白表达并未降低，并且还下调了AKT/GSK-3β/β-连环蛋白通路。然而，TGF-β1刺激的SNU-354细胞（CD44/TGF-β1(+)）表现出较低的E-钙黏蛋白和较高的N-钙黏蛋白表达，同时AKT/GSK-3β/β-连环蛋白通路活性增加。CD44/TGF-β1(+) SNU-354细胞还表现出迁移增强并形成更大的球体，而用TGF-β1抑制剂SB431542处理后，TGF-β1诱导的干细胞特性恢复到原始状态。用SB431542处理的SNU-368（CD44/TGF-β1(-)）细胞在伤口愈合试验中也表现出N-钙黏蛋白和AKT/GSK-3β/β-连环蛋白通路活性降低以及细胞运动性进一步下降。然而，SNU-354细胞中的CD44敲低即使在用TGF-β1处理后也不会诱导EMT。最后，在SNU-368细胞中，对CD44和TGF-β1的双重抑制比单一抑制更强烈地进一步降低了迁移和球体形成。总之，当前研究证明了在肝癌细胞中，CD44和TGF-β1通过AKT/GSK-3β/β-连环蛋白通路在EMT诱导和CSC特性方面存在协同相互作用。
