Li Lu-Chun, Peng Yang, Liu Yan-Mim, Wang Lu-Lu, Wu Xiao-Ling
Department of Gastroenterology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, P.R. China.
Oncol Lett. 2014 Jun;7(6):2160-2164. doi: 10.3892/ol.2014.1980. Epub 2014 Mar 18.
The Notch signaling pathway may be important in the development and progression of several malignancies. However, the functions of Notch signaling in epithelial-mesenchymal transition (EMT) remain largely unknown. The aim of the present study was to delineate Notch1 expression in gastric cancer (GC) and its function in GC EMT. Using quantitative polymerase chain reaction and western blot analysis, the expression of Notch1 was found to increase in GC cell lines compared with the normal gastric mucosa cell line. In addition, Notch1 expression was found to be downregulated in the non-metastatic-derived GC cell line compared with the metastatic-derived cell line. Furthermore, Notch1 expression was significantly increased in the tumor tissues compared with the adjacent normal mucosa tissues, as well as in patients with metastases than in patients without metastases. To explore the role of the Notch1 signaling pathway in EMT, the GC cell lines, AGS and MKN45, were treated with γ-secretase inhibitor DAPT. Using MTT, Transwell and clonality assays, DAPT was found to inhibit the expression of the Notch1 downstream target, Hes1, and impair the ability of the GC cell lines to migrate, invade and proliferate. The protein levels of the mesenchymal markers, vimentin, neural cadherin and Snail, were decreased; however, the expression of the epithelial marker, epithelial cadherin, was increased in the GC cell lines treated with DAPT. These results indicated that the Notch1 signaling pathway may be important in the development and progression of GC. In conclusion, DAPT inhibits the Notch1 signaling pathway, as well as the growth, invasion, metastasis and EMT of GC cells.
Notch信号通路可能在多种恶性肿瘤的发生和发展中起重要作用。然而，Notch信号在上皮-间质转化（EMT）中的功能仍 largely未知。本研究的目的是描绘Notch1在胃癌（GC）中的表达及其在GC EMT中的功能。通过定量聚合酶链反应和蛋白质印迹分析，发现与正常胃黏膜细胞系相比，GC细胞系中Notch1的表达增加。此外，与转移性来源的GC细胞系相比，非转移性来源的GC细胞系中Notch1表达下调。此外，与相邻正常黏膜组织相比，肿瘤组织中Notch1表达显著增加，且有转移的患者比无转移的患者中Notch1表达更高。为了探究Notch1信号通路在EMT中的作用，用γ-分泌酶抑制剂DAPT处理GC细胞系AGS和MKN45。通过MTT、Transwell和克隆形成实验，发现DAPT抑制Notch1下游靶点Hes1的表达，并损害GC细胞系的迁移、侵袭和增殖能力。间充质标志物波形蛋白、神经钙黏蛋白和Snail的蛋白水平降低；然而，在用DAPT处理的GC细胞系中，上皮标志物上皮钙黏蛋白的表达增加。这些结果表明Notch1信号通路可能在GC的发生和发展中起重要作用。总之，DAPT抑制Notch1信号通路以及GC细胞的生长、侵袭、转移和EMT。
