Hotair mediates hepatocarcinogenesis through suppressing miRNA-218 expression and activating P14 and P16 signaling

• Published in: Journal of hepatology Vol. 63; no. 4; pp. 886 - 895
• Main Authors: Fu, Wei-Ming, Zhu, Xiao, Wang, Wei-Mao, Lu, Ying-Fei, Hu, Bao-Guang, Wang, Hua, Liang, Wei-Cheng, Wang, Shan-Shan, Ko, Chun-Hay, Waye, Mary Miu-Yee, Kung, Hsiang-Fu, Li, Gang, Zhang, Jin-Fang
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.10.2015
• Subjects: Animals; Blotting, Western; Carcinogenesis - genetics; Carcinoma, Hepatocellular - genetics; Carcinoma, Hepatocellular - metabolism; Carcinoma, Hepatocellular - pathology; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cyclin-Dependent Kinase Inhibitor p16; Gastroenterology and Hepatology; Gene Expression Regulation, Neoplastic; Hepatocellular carcinoma; Hotair; Humans; Immunoprecipitation; Liver Neoplasms, Experimental - genetics; Liver Neoplasms, Experimental - metabolism; Liver Neoplasms, Experimental - pathology; Mice; microR-218; MicroRNAs - biosynthesis; MicroRNAs - genetics; Neoplasm Proteins - biosynthesis; Neoplasm Proteins - genetics; P14; P16; Promoter Regions, Genetic; Proteins - genetics; Proteins - metabolism; Reverse Transcriptase Polymerase Chain Reaction; RNA, Long Noncoding - biosynthesis; RNA, Long Noncoding - genetics; RNA, Neoplasm - genetics; Signal Transduction - genetics; lncRNAs; ceRNA; siBmi-1; 3′UTR; Lv-miR218; HCC; Hepatocellular carcinoma; siRNA; MTT; miR-218; microR-218; Hotair; P14; CDS; PRC2; P16; NC; shRNA; Bmi-1; siHotair; RIP; miRNA; PI; EZH2; microRNAs; polycomb repressive complex 2; small interfering RNA; 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; specific siRNA of Bmi-1; B lymphoma mouse Moloney leukemia virus insertion region 1; Enhancer of zeste homolog 2; RNA immunoprecipitation; the coding sequence; propidium iodide; specific siRNA of Hotair; hepatocellular carcinoma; negative control RNA duplex; 3′ untranslated region; Long non-coding RNAs; competitive endogenous RNAs; short-hairpin RNA; Hox transcript antisense intergenic RNA; lentiviral pre-miR218 vector; microRNA-218
• ISSN: 0168-8278; 1600-0641; 1600-0641
• DOI: 10.1016/j.jhep.2015.05.016

[Display omitted] Long non-coding RNA Hotair has been considered as a pro-oncogene in multiple cancers. Although there is emerging evidence that reveals its biological function and the association with clinical prognosis, the precise mechanism remains largely elusive. We investigated the function and mechanism of Hotair in hepatocellular carcinoma (HCC) cell models and a xenograft mouse model. The regulatory network between miR-218 and Hotair was elucidated by RNA immunoprecipitation and luciferase reporter assays. Finally, the correlation between Hotair, miR-218 and the target gene Bmi-1 were evaluated in 52 paired HCC specimens. In this study, we reported that Hotair negatively regulated miR-218 expression in HCC, which might be mediated through an EZH2-targeting-miR-218-2 promoter regulatory axis. Further investigation revealed that Hotair knockdown dramatically inhibited cell viability and induced G1-phase arrest in vitro and suppressed tumorigenicity in vivo by promoting miR-218 expression. Oncogene Bmi-1 was shown to be a functional target of miR-218, and the main downstream targets signaling, P16Ink4a and P14ARF, were activated in Hotair-suppressed tumorigenesis. In primary human HCC specimens, Hotair and Bmi-1 were concordantly upregulated whereas miR-218 was downregulated in these tissues. Furthermore, Hotair was inversely associated with miR-218 expression and positively correlated with Bmi-1 expression in these clinical tissues. Hotair silence activates P16Ink4a and P14ARF signaling by enhancing miR-218 expression and suppressing Bmi-1 expression, resulting in the suppression of tumorigenesis in HCC.