Huang Tingting, Kang Wei, Zhang Bin, Wu Feng, Dong Yujuan, Tong Joanna H M, Yang Weiqin, Zhou Yuhang, Zhang Li, Cheng Alfred S L, Yu Jun, To Ka Fai
Department of Anatomical and Cellular Pathology, State Key Laboratory in Oncology in South China, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, SAR, PR China.
Institute of Digestive Disease, Partner State Key Laboratory of Digestive Disease, The Chinese University of Hong Kong, Hong Kong, SAR, PR China.
Mol Cancer. 2016 Jan 22;15:9. doi: 10.1186/s12943-016-0493-7.
NF-κB signaling pathway plays an important role in gastric carcinogenesis. The basic expression and functional role of NFKB1 and RELA (components of canonical NF-κB pathway) in gastric cancer (GC) have not been well elucidated. In this study, the role of NFKB1 and RELA in gastric tumorigenesis will be investigated and their regulation by microRNAs (miRNAs) will be deeply explored.
The mRNA and protein expression of NFKB1 and RELA were investigated by qRT-PCR and Western blot in GC cell lines and primary tumors. The functional roles of NFKB1 and RELA in GC were demonstrated by MTT proliferation assay, monolayer colony formation, cell invasion and migration, cell cycle analysis and in vivo study through siRNA mediated knockdown. Identification of NFKB1 as a direct target of tumor suppressor miRNA miR-508-3p was achieved by expression regulation assays together with dual luciferase activity experiments.
NFKB1 and RELA were up-regulated in GC cell lines and primary tumors compared with normal gastric epithelium cells and their upregulation correlation with poor survival in GC. siRNA mediated knockdown of NFKB1 or RELA exhibited anti-oncogenic effect both in vitro and in vivo. NFKB1 was further revealed to be a direct target of miR-508-3p in gastric tumorigenesis and their expression showed negative correlation in primary GC samples. miR-508-3p was down-regulated in GC cells compared with normal gastric epithelium samples and its ectopic expression in GC cell lines also exerts tumor suppressor function. NFKB1 re-expression was found to partly abolish the tumor-suppressive effect of miR-508-3p in GC.
All these findings supports that canonical NF-κB signaling pathway is activated in GC at least by the inactivation of miR-508-3p and this might have therapeutic potential in GC treatment.
NF-κB信号通路在胃癌发生过程中起重要作用。NFKB1和RELA（经典NF-κB通路的组成部分）在胃癌（GC）中的基础表达及功能作用尚未得到充分阐明。在本研究中，将探究NFKB1和RELA在胃癌发生中的作用，并深入探讨它们受微小RNA（miRNA）的调控情况。
通过qRT-PCR和蛋白质免疫印迹法检测GC细胞系和原发性肿瘤中NFKB1和RELA的mRNA及蛋白质表达。通过MTT增殖试验、单层集落形成、细胞侵袭与迁移、细胞周期分析以及通过小干扰RNA（siRNA）介导的敲低进行体内研究，来证明NFKB1和RELA在GC中的功能作用。通过表达调控试验及双荧光素酶活性实验，确定NFKB1为肿瘤抑制性miRNA miR-508-3p的直接靶点。
与正常胃上皮细胞相比，NFKB1和RELA在GC细胞系和原发性肿瘤中上调，且它们的上调与GC患者的不良生存相关。siRNA介导的NFKB1或RELA敲低在体外和体内均表现出抗癌作用。进一步发现NFKB1是miR-508-3p在胃癌发生中的直接靶点，且它们在原发性GC样本中的表达呈负相关。与正常胃上皮样本相比，miR-508-3p在GC细胞中下调，其在GC细胞系中的异位表达也发挥肿瘤抑制功能。发现NFKB1的重新表达部分消除了miR-508-3p在GC中的肿瘤抑制作用。
所有这些发现支持经典NF-κB信号通路在GC中至少通过miR-508-3p的失活而被激活，这可能在GC治疗中具有治疗潜力。
