title: MiR-20a triggers metastasis of gallbladder carcinoma.
abstract: OBJECTIVE
  The dysfunction of miRNAs has been demonstrated to participate in the development of various tumors. However, whether miRNAs are involved in metastasis and progression of gallbladder carcinoma (GBC) remains unknown.
  
  
  METHODS
  A new designed gain-of-function miRNA screening technology was applied to filter out pro-metastatic miRNAs in GBC. Their expression in GBC tissues was validated by real-time PCR. The biological functions of miRNAs were intensively studied by transwell, immunoblot, immunohistochemical, and in situ hybridization assays. Tumorigenicity and liver metastasis were further examined in nude mice.
  
  
  RESULTS
  Of 880 miRNAs, 17 were filtered out as the prominent metastatic inducers of GBCs. Among them, the upregulation of pro-metastatic miR-20a was closely associated with local invasion, distant metastasis, and poor prognosis of 67 followed-up GBC patients, clinically. Patients with higher miR-20a expression exhibited worse overall survival (OS and median OS time was 5 and 20 months, respectively) than the lower expression group. A dramatically increased TGF-β1 level was found in GBC patients, which was responsible for the elevation of miR-20a. The ectopic expression of miR-20a could induce epithelial-mesenchymal transition and enhance metastasis of GBC cells in vitro and in vivo, by directly targeting the 3' UTR of Smad7, and subsequently promoting nuclear translocation of β-catenin. Conversely, the blockage of miR-20a by specific antagomir effectively restored the expression of Smad7 and attenuated TGF-β-induced cell metastasis.
  
  
  CONCLUSIONS
  TGF-β1-mediated activation of the miR-20a/Smad7/β-catenin axis plays a pivotal role in the pathogenesis and worse prognosis of GBCs and may serve as a potential therapeutic target in the future.
authors.affiliation: International Co-Operation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Institute, Second Military Medical University, Shanghai 200438, PR China.
authors.forename: Yanxin
authors.initials: Y
authors.lastname: Chang
authors.forename: Chen
authors.initials: C
authors.lastname: Liu
authors.forename: Jiahe
authors.initials: J
authors.lastname: Yang
authors.forename: Gaomiyang
authors.initials: G
authors.lastname: Liu
authors.forename: Feiling
authors.initials: F
authors.lastname: Feng
authors.forename: Jing
authors.initials: J
authors.lastname: Tang
authors.forename: Liang
authors.initials: L
authors.lastname: Hu
authors.forename: Liang
authors.initials: L
authors.lastname: Li
authors.forename: Feng
authors.initials: F
authors.lastname: Jiang
authors.forename: Caiyang
authors.initials: C
authors.lastname: Chen
authors.forename: Ruoyu
authors.initials: R
authors.lastname: Wang
authors.forename: Yingcheng
authors.initials: Y
authors.lastname: Yang
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Jiang
authors.forename: Mengchao
authors.initials: M
authors.lastname: Wu
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
authors.forename: Hongyang
authors.initials: H
authors.lastname: Wang
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D018450:Disease Progression; D058750:Epithelial-Mesenchymal Transition / Q000235:genetics; D005260:Female; D005706:Gallbladder Neoplasms / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D064593:Heterografts; D006801:Humans; D008114:Liver Neoplasms, Experimental / Q000235:genetics / Q000378:metabolism / Q000556:secondary; D008297:Male; D051379:Mice; D008819:Mice, Nude; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism*; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis / Q000235:genetics*; D009368:Neoplasm Transplantation; D011379:Prognosis; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D051906:Smad7 Protein / Q000235:genetics / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000378:metabolism; D051176:beta Catenin / Q000235:genetics / Q000378:metabolism
chemical_list: C495270:CTNNB1 protein, human; C534451:MIRN20a microRNA, human; D035683:MicroRNAs; D012334:RNA, Neoplasm; C497806:SMAD7 protein, human; D051906:Smad7 Protein; D053773:Transforming Growth Factor beta1; D051176:beta Catenin
keywords: EMT; GBC; Gallbladder carcinoma; Smad7; TGF-β1; epithelial-mesenchymal transition; gallbladder carcinoma; microRNAs; mothers against decapentaplegic homolog 7; transforming growth factor-β1