title: Hotair mediates hepatocarcinogenesis through suppressing miRNA-218 expression and activating P14 and P16 signaling.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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, P16(Ink4a) and P14(ARF), 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.
  
  
  CONCLUSIONS
  Hotair silence activates P16(Ink4a) and P14(ARF) signaling by enhancing miR-218 expression and suppressing Bmi-1 expression, resulting in the suppression of tumorigenesis in HCC.
authors.affiliation: School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China; Guangzhou Institute of Advanced Technology, Chinese Academy of Sciences, Guangzhou 511458, China.
authors.forename: Wei-Ming
authors.initials: WM
authors.lastname: Fu
authors.affiliation: School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China; Guangdong Province Key Laboratory of Medical Molecular Diagnosis, Guangdong Medical College, Dong Guan 523808, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Zhu
authors.affiliation: School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Wei-Mao
authors.initials: WM
authors.lastname: Wang
authors.affiliation: Department of Orthopaedics & Traumatology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, China.
authors.forename: Ying-Fei
authors.initials: YF
authors.lastname: Lu
authors.affiliation: Department of Gastrointestinal Surgery, The Affiliated Hospital of Binzhou Medical University, Binzhou, Shandong, China.
authors.forename: Bao-Guang
authors.initials: BG
authors.lastname: Hu
authors.affiliation: Stanley Ho Centre for Emerging Infectious Diseases, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Wang
authors.affiliation: School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Wei-Cheng
authors.initials: WC
authors.lastname: Liang
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
authors.forename: Shan-Shan
authors.initials: SS
authors.lastname: Wang
authors.affiliation: Institute of Chinese Medicine, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Chun-Hay
authors.initials: CH
authors.lastname: Ko
authors.affiliation: School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Mary Miu-Yee
authors.initials: MM
authors.lastname: Waye
authors.affiliation: School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China; Stanley Ho Centre for Emerging Infectious Diseases, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Hsiang-Fu
authors.initials: HF
authors.lastname: Kung
authors.affiliation: Department of Orthopaedics & Traumatology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, China; School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China; Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China; Stem Cells and Regenerative Medicine Laboratory, Lui Che Woo Institute of Innovative Medicine, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, China. Electronic address: gangli@cuhk.edu.hk.
authors.forename: Gang
authors.initials: G
authors.lastname: Li
authors.affiliation: Department of Orthopaedics & Traumatology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, China; School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China; Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China; Stem Cells and Regenerative Medicine Laboratory, Lui Che Woo Institute of Innovative Medicine, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, China. Electronic address: zhangjf06@cuhk.edu.hk.
authors.forename: Jin-Fang
authors.initials: JF
authors.lastname: Zhang
mesh_terms: D000818:Animals; D015153:Blotting, Western; D063646:Carcinogenesis / Q000235:genetics*; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival; D019941:Cyclin-Dependent Kinase Inhibitor p16; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D047468:Immunoprecipitation; D008114:Liver Neoplasms, Experimental / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D051379:Mice; D035683:MicroRNAs / Q000096:biosynthesis / Q000235:genetics*; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000235:genetics*; D011401:Promoter Regions, Genetic; D011506:Proteins / Q000235:genetics* / Q000378:metabolism; D062085:RNA, Long Noncoding / Q000096:biosynthesis / Q000235:genetics*; D012334:RNA, Neoplasm / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000235:genetics
chemical_list: C000614131:CDKN2A protein, human; D019941:Cyclin-Dependent Kinase Inhibitor p16; C000608169:HOTAIR long non-coding RNA, mouse; C426009:LAMTOR2 protein, mouse; C547684:MIRN218 microRNA, mouse; D035683:MicroRNAs; D009363:Neoplasm Proteins; D011506:Proteins; D062085:RNA, Long Noncoding; D012334:RNA, Neoplasm
keywords: Hepatocellular carcinoma; Hotair; P14; P16; microR-218