title: MicroRNA-101 inhibits human hepatocellular carcinoma progression through EZH2 downregulation and increased cytostatic drug sensitivity.
abstract: OBJECTIVE
  Oncogene polycomb group protein enhancer of zeste homolog 2 (EZH2) has been proposed to be a target gene of putative tumor suppressor microRNA-101 (miR-101). The aim of our study was to investigate the functional role of both miR-101 and EZH2 in human hepatocellular carcinoma (HCC).
  
  
  METHODS
  MiR-101 and EZH2 expressions were evaluated in tumor tissues of 99 HCC patients and 7 liver cancer cell lines by real-time PCR. Luciferase reporter assay was employed to validate whether EZH2 represents a target gene of miR-101. The effect of miR-101 on HCC growth as well as programmed cell death was studied in vitro and in vivo.
  
  
  RESULTS
  MiR-101 expression was significantly downregulated in most of HCC tissues and all cell lines, whereas EZH2 was significantly overexpressed in most of HCC tissues and all cell lines. There was a negative correlation between expression levels of miR-101 and EZH2. Luciferase assay results confirmed EZH2 as a direct target gene of miR-101, which negatively regulates EZH2 expression in HCC. Ectopic overexpression of miR-101 dramatically repressed proliferation, invasion, colony formation as well as cell cycle progression in vitro and suppressed tumorigenicity in vivo. Furthermore, miR-101 inhibited autophagy and synergized with either doxorubicin or fluorouracil to induce apoptosis in tumor cells.
  
  
  CONCLUSIONS
  Tumor suppressor miR-101 represses HCC progression through directly targeting EZH2 oncogene and sensitizes liver cancer cells to chemotherapeutic treatment. Our findings provide significant insights into molecular mechanisms of hepatocarcinogenesis and may have clinical relevance for the development of novel targeted therapies for HCC.
authors.affiliation: Department of Transplant Medicine, University Hospital Münster, Münster, Germany; Department of Gastroenterology and Hepatology, University Hospital Essen, Essen, Germany; HPB Surgical Department, Sun Yat-sen Memorial Hospital, Guangzhou, China.
authors.forename: Leibo
authors.initials: L
authors.lastname: Xu
authors.affiliation: Department of Transplant Medicine, University Hospital Münster, Münster, Germany; Department of General, Visceral and Transplantation Surgery, University Hospital Essen, Essen, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Beckebaum
authors.affiliation: Department of Transplant Medicine, University Hospital Münster, Münster, Germany; Fundeni Clinical Institute, Gastroenterology and Hepatology Center, Bucharest, Romania.
authors.forename: Speranta
authors.initials: S
authors.lastname: Iacob
authors.affiliation: Department of Transplant Medicine, University Hospital Münster, Münster, Germany; Department of Gastroenterology and Hepatology, University Hospital Essen, Essen, Germany.
authors.forename: Gang
authors.initials: G
authors.lastname: Wu
authors.affiliation: Department of General, Visceral and Transplantation Surgery, University Hospital Essen, Essen, Germany.
authors.forename: Gernot M
authors.initials: GM
authors.lastname: Kaiser
authors.affiliation: Department of General, Visceral and Transplantation Surgery, University Hospital Essen, Essen, Germany; Department of General and Visceral Surgery, University Hospital Münster, Münster, Germany.
authors.forename: Arnold
authors.initials: A
authors.lastname: Radtke
authors.affiliation: HPB Surgical Department, Sun Yat-sen Memorial Hospital, Guangzhou, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Liu
authors.affiliation: Department of Transplant Medicine, University Hospital Münster, Münster, Germany.
authors.forename: Iyad
authors.initials: I
authors.lastname: Kabar
authors.affiliation: Department of Transplant Medicine, University Hospital Münster, Münster, Germany.
authors.forename: Hartmut H
authors.initials: HH
authors.lastname: Schmidt
authors.affiliation: Institute of Virology, University Hospital Essen, Essen, Germany; Hepatology Unit and Department of Infectious Diseases, Nanfang Hospital, Guangzhou, China.
authors.forename: Xiaoyong
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Institute of Virology, University Hospital Essen, Essen, Germany.
authors.forename: Mengji
authors.initials: M
authors.lastname: Lu
authors.affiliation: Department of Transplant Medicine, University Hospital Münster, Münster, Germany; Department of Gastroenterology and Hepatology, University Hospital Essen, Essen, Germany. Electronic address: vito.cicinnati@ukmuenster.de.
authors.forename: Vito R
authors.initials: VR
authors.lastname: Cicinnati
mesh_terms: D000818:Animals; D017209:Apoptosis; D001343:Autophagy; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy / Q000235:genetics / Q000473:pathology / Q000517:prevention & control*; D018450:Disease Progression; D015536:Down-Regulation; D000071221:Enhancer of Zeste Homolog 2 Protein; D005260:Female; D056945:Hep G2 Cells; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000473:pathology / Q000517:prevention & control*; D008807:Mice, Inbred BALB C; D035683:MicroRNAs / Q000502:physiology*; D009361:Neoplasm Invasiveness; D063151:Polycomb Repressive Complex 2 / Q000235:genetics* / Q000502:physiology
chemical_list: C534072:MIRN101 microRNA, human; D035683:MicroRNAs; C498409:EZH2 protein, human; D000071221:Enhancer of Zeste Homolog 2 Protein; D063151:Polycomb Repressive Complex 2
keywords: 4′,6-diamidino-2-phenylindole; 5-FU; 5-fluorouracil; 7-AAD; 7-amino-actinomycin D; APH; Anti-miR-101; Apoptosis; Autophagy; Baf; CLSM; DAPI; DMEM; DPBS; Doxo; Dulbecco’s Modified Eagle’s Medium; Dulbecco’s Phosphate-Buffered Saline; ECL; EZH2; FBS; GAPDH; HCC; HCC tissues; HH; HRP; International Union Against Cancer/American Joint Committee on Cancer; L; LAMP-1; LC3; LV; Mcl-1; N; PARP; PCD; Pre-miR-101; SD; SDS-PAGE; T; Target gene; UICC/AJCC; UTR; V; W; aphidicolin; bafilomycin; confocal laser scanning microscopy; doxorubicin; enhanced chemiluminescence; enhancer of zeste homolog 2; fetal bovine serum; glyceraldehyde 3-phosphate dehydrogenase; h; hepatocellular carcinoma; horseradish peroxidase; hour(s); human hepatocytes; length; lentiviral; lysosome-associated membrane protein; mRNA(s); messenger RNA(s); miR-101; miR-101 inhibitor; miR-101 precursor; miR-C; miRNA(s); microRNA; microRNA control; microRNA(s); microRNA-101; microtubule-associated protein light chain 3; min; minute(s); mut; mutant type; myeloid cell leukemia sequence 1; non-tumor tissues; pRb; phosphorylated retinoblastoma; poly adenosine diphosphate ribose polymerase; programmed cell death; qPCR; quantitative real-time PCR; shRNA; short hairpin RNA; siR-C; siRNA control; siRNAs; small interfering RNAs; sodium dodecyl sulfate-polyacrylamide gel electrophoresis; standard deviation; untranslated region; volume; week(s); width; wild type; wk; wt