title: MicroRNA-107 promotes proliferation of gastric cancer cells by targeting cyclin dependent kinase 8.
abstract: BACKGROUND
  The biological processes and molecular mechanisms underlying miR-107 remain unclear in gastric cancer(GC). In this study, we aimed to investigate the expression, biological functions and mechanisms of miR-107 in GC.
  
  
  METHODS
  Quantitative real-time RT-PCR was used to test miR-107 expression. MTT and colony formation assays were conducted to explore the potential function of miR-107 in human GC cell line SGC7901. The target gene was determined by bioinformatic algorithms, dual luciferase reporter assay, RT-PCR and Western blot.
  
  
  RESULTS
  Expression of miR-107 was significantly elevated in GC cell line than that in gastric epithelial cell line(p = 0.012). We found that miR-107 inhibitor transfection significantly decreased the proliferation of GC cell line, and clone formation rate of miR-107 inhibitor transfected group was significantly lower than that of control group. Luciferase assays using a reporter carrying a putative miR-107 target site in the 3'untranslated region (3'-UTR) of cyclin dependent kinase 8 (CDK8) revealed that miR-107 directly targets CDK8. The expression level of CDK8 mRNA and protein in miR-107 inhibitor transfected GC cell line was significantly decreased compared with control group.
  
  
  CONCLUSIONS
  Our findings indicate that miR-107 is upregulated in GC and affects the proliferation of GC cells, partially through the regulation of CDK8.
  The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_164.
authors.forename: Yan-qiang
authors.initials: YQ
authors.lastname: Song
authors.forename: Xu-hui
authors.initials: XH
authors.lastname: Ma
authors.forename: Gui-liang
authors.initials: GL
authors.lastname: Ma
authors.forename: Bin
authors.initials: B
authors.lastname: Lin
authors.forename: Chao
authors.initials: C
authors.lastname: Liu
authors.forename: Quan-jiang
authors.initials: QJ
authors.lastname: Deng
authors.affiliation: Department of general surgery, Qingdao Municipal Hospital (East), Medical College of Qingdao University, No,5 Donghai Middle Road, Qingdao 266071, People's Republic of China. qd_lvwenping@126.com.
authors.forename: Wen-ping
authors.initials: WP
authors.lastname: Lv
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics; D017209:Apoptosis; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D056850:Cyclin-Dependent Kinase 8 / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic; D017930:Genes, Reporter; D006801:Humans; D035683:MicroRNAs / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D013274:Stomach Neoplasms / Q000235:genetics* / Q000473:pathology; D014162:Transfection; D015854:Up-Regulation
chemical_list: D020413:3' Untranslated Regions; C549045:MIRN107 microRNA, human; D035683:MicroRNAs; D012333:RNA, Messenger; C095686:CDK8 protein, human; D056850:Cyclin-Dependent Kinase 8