title: The long intergenic noncoding RNA UFC1, a target of MicroRNA 34a, interacts with the mRNA stabilizing protein HuR to increase levels of β-catenin in HCC cells.
abstract: OBJECTIVE
  Altered activities of long noncoding RNAs (lncRNAs) have been associated with cancer development. We investigated the mechanisms by which the long intergenic noncoding RNA UFC1 (lincRNA-UFC1) promotes progression of hepatocellular carcinoma (HCC), using human tissues and cell lines.
  
  
  METHODS
  We used microarrays to compare expression profiles of lncRNAs in HCC samples and adjacent nontumor tissues (controls) from 7 patients. HCC and nontumor tissues were collected from 2006 through 2012 from patients in Guangzhou, China. We used quantitative real-time polymerase chain reaction to measure levels of lincRNA-UFC1 in tissues from 49 patients, and in situ hybridization to measure levels in samples from 131 patients; clinical data were collected from patients for up to 5 years. The lincRNA-UFC1 was expressed transgenically, or knocked down with short hairpin RNAs, in BEL-7402, SK-Hep1, Huh7, and MHCC-97H HCC cell lines; luciferase reporter and RNA immunoprecipitation and pull-down assays were performed. We also analyzed growth of xenograft tumors from these cells in BALB/c nude mice.
  
  
  RESULTS
  Levels of the lincRNA-UFC1 were increased in HCC tissues compared with controls, and associated with tumor size, Barcelona Clinic Liver Cancer stage, and patient outcomes. Transgenic expression of the lincRNA-UFC1 in HCC cells promoted their proliferation and cell-cycle progression and inhibited apoptosis, whereas short hairpin RNA knockdown of lincRNA-UFC1 had opposite effects. Xenograft tumors grown from cells overexpressing lincRNA-UFC1 had larger mean volumes and weights, and formed more rapidly, than tumors grown from control cells. Tumors grown from lincRNA-UFC1 knockdown were smaller than controls. The lincRNA-UFC1 interacted directly with the messenger RNA (mRNA) stabilizing protein HuR (encoded by ELAVL1) to increase levels of β-catenin mRNA (encoded by CTNNB1) and protein. Levels of lincRNA-UFC1 correlated with those of β-catenin in HCC tissues. In contrast, there was a negative correlation between levels of microRNA 34a and lincRNA-UFC1 in HCC tissues; microRNA 34a reduced the stability of lincRNA-UFC1.
  
  
  CONCLUSIONS
  The lincRNA-UFC1, a target of microRNA 34a, promotes proliferation and reduces apoptosis in HCC cells to promote growth of xenograft tumors in mice. It interacts directly with the mRNA stabilizing protein HuR to regulate levels of β-catenin in HCC cells.
authors.affiliation: Hepatology Unit and Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, China; Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Chuanhui
authors.initials: C
authors.lastname: Cao
authors.affiliation: Hepatology Unit and Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, China; Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Jingyuan
authors.initials: J
authors.lastname: Sun
authors.affiliation: Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Dongyan
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Xuejun
authors.initials: X
authors.lastname: Guo
authors.affiliation: Center of Molecular Medicine, University of Georgia, Athens, Georgia; Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia.
authors.forename: Liwei
authors.initials: L
authors.lastname: Xie
authors.affiliation: Cancer Research Institute, Southern Medical University, Guangzhou, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, China. Electronic address: wudehua.gd@gmail.com.
authors.forename: Dehua
authors.initials: D
authors.lastname: Wu
authors.affiliation: Hepatology Unit and Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, China. Electronic address: liuli.fimmu@gmail.com.
authors.forename: Li
authors.initials: L
authors.lastname: Liu
mesh_terms: D000818:Animals; D017209:Apoptosis; D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000473:pathology; D045744:Cell Line, Tumor; D051959:ELAV Proteins / Q000502:physiology*; D000067780:ELAV-Like Protein 1; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics* / Q000473:pathology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D035683:MicroRNAs / Q000502:physiology; D020871:RNA Stability; D044763:Ubiquitin-Conjugating Enzymes / Q000502:physiology*; D051176:beta Catenin / Q000032:analysis*
chemical_list: D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; C098770:ELAVL1 protein, human; C522425:MIRN34 microRNA, human; D035683:MicroRNAs; C502096:UFC1 protein, human; D051176:beta Catenin; D044763:Ubiquitin-Conjugating Enzymes
keywords: Liver Cancer; Proliferation; Tumor Progression; mRNA Stabilizing Protein