title: miR-373 negatively regulates methyl-CpG-binding domain protein 2 (MBD2) in hilar cholangiocarcinoma.
abstract: BACKGROUND
  microRNAs (miRNAs) are a class of non-coding, single-stranded RNA molecules that regulate gene expression at the posttranscriptional level. Methyl-CpG-binding domain proteins (MBPs) are transcription repressors through binding to methylated gene promoters. Recent studies have shown that the effect of miRNAs on DNA methylation by targeting DNA methyltransferase (DNMTs) and/or MBPs plays an important role in various human cancers.
  
  
  OBJECTIVE
  This study focuses on the regulation of MBPs by miR-373 and its downstream effect in hilar cholangiocarcinoma.
  
  
  METHODS
  miR-373 was investigated by TaqMan miRNA Assay; mRNA and protein of MBD1, MBD2, and Mecp2 were determined by QuantiTect(®) Primer Assays and Western blotting, respectively; RASSF1A mRNA was measured by SYBR-Green real-time PCR; The targeting at MBD2-3'UTR by miR-373 was evaluated by dual-luciferase reporter gene assay.
  
  
  RESULTS
  miR-373 decreased and closely associated with poor cell differentiation, advanced clinical stage, and shorter survival in hilar cholangiocarcinoma; MBD2 exclusively over-expressed and reciprocally related to miR-373; precursor miR-373 inhibited the luciferase activity of MBD2-3'UTR construct; exogenous miR-373 suppressed the expression of MBD2 and enhanced RASSF1A mRNA in QBC(939) cells; anti-miR-373 inhibitor up-regulated the expression of MBD2 and reduced RASSF1A mRNA in HIBEpic cells.
  
  
  CONCLUSIONS
  miR-373 is one negative regulator of MBD2. In hilar cholangiocarcinoma, down-expression of miR-373 leads to increase of MBD2, which in turn suppresses the methylation-mediated gene such as RASSF1A.
authors.affiliation: Department of General Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Road, 430030 Wuhan, China.
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Chen
authors.forename: Jian
authors.initials: J
authors.lastname: Luo
authors.forename: Rui
authors.initials: R
authors.lastname: Tian
authors.forename: Huawen
authors.initials: H
authors.lastname: Sun
authors.forename: Shengquan
authors.initials: S
authors.lastname: Zou
mesh_terms: D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology*; D006801:Humans; D018285:Klatskin Tumor / Q000378:metabolism*; D008297:Male; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D008875:Middle Aged; D009367:Neoplasm Staging; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; C489325:MBD2 protein, human; C527114:MIRN373 microRNA, human; D035683:MicroRNAs; C411762:RASSF1 protein, human; D025521:Tumor Suppressor Proteins