Park Song Yi, Shin Jee-Hye, Kee Sun-Ho
Department of Microbiology, College of Medicine, Korea University, Seoul, Korea.
Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland, USA.
Cancer Sci. 2017 Sep;108(9):1769-1777. doi: 10.1111/cas.13321. Epub 2017 Aug 11.
β-Catenin is a central player in Wnt signaling, and activation of Wnt signaling is associated with cancer development. E-cadherin in complex with β-catenin mediates cell-cell adhesion, which suppresses β-catenin-dependent Wnt signaling. Recently, a tumor-suppressive role for E-cadherin has been reconsidered, as re-expression of E-cadherin was reported to enhance the metastatic potential of malignant tumors. To explore the role of E-cadherin, we established an E-cadherin-expressing cell line, EC96, from AGS cells that featured undetectable E-cadherin expression and a high level of Wnt signaling. In EC96 cells, E-cadherin re-expression enhanced cell proliferation, although Wnt signaling activity was reduced. Subsequent analysis revealed that nuclear factor-κB (NF-κB) activation and consequent c-myc expression might be involved in E-cadherin expression-mediated cell proliferation. To facilitate rapid proliferation, EC96 cells enhance glucose uptake and produce ATP using both mitochondria oxidative phosphorylation and glycolysis, whereas AGS cells use these mechanisms less efficiently. These events appeared to be mediated by NF-κB activation. Therefore, E-cadherin re-expression and subsequent induction of NF-κB signaling likely enhance energy production and cell proliferation.
β-连环蛋白是Wnt信号通路的核心分子,Wnt信号通路的激活与癌症发展相关。与β-连环蛋白结合的E-钙黏蛋白介导细胞间黏附,从而抑制β-连环蛋白依赖性Wnt信号通路。最近,E-钙黏蛋白的肿瘤抑制作用被重新审视,因为有报道称E-钙黏蛋白的重新表达会增强恶性肿瘤的转移潜能。为了探究E-钙黏蛋白的作用,我们从AGS细胞中建立了一个表达E-钙黏蛋白的细胞系EC96,AGS细胞的特点是检测不到E-钙黏蛋白表达且Wnt信号通路水平较高。在EC96细胞中,尽管Wnt信号活性降低,但E-钙黏蛋白的重新表达增强了细胞增殖。随后的分析表明,核因子κB(NF-κB)的激活以及随之而来的c-myc表达可能参与了E-钙黏蛋白表达介导的细胞增殖。为了促进快速增殖,EC96细胞增强葡萄糖摄取,并通过线粒体氧化磷酸化和糖酵解产生ATP,而AGS细胞对这些机制的利用效率较低。这些事件似乎是由NF-κB激活介导的。因此,E-钙黏蛋白的重新表达以及随后诱导的NF-κB信号通路可能会增强能量产生和细胞增殖。