title: Mutual regulation between microRNA-373 and methyl-CpG-binding domain protein 2 in hilar cholangiocarcinoma.
abstract: OBJECTIVE
  To investigate the reciprocal modulation between microRNA (miRNA) and DNA methylation via exploring the correlation between miR-373 and methyl-CpG-binding domain protein (MBD)2.
  
  
  METHODS
  MiR-373 expression was examined using the TaqMan miRNA assay. Methylation of miR-373 was investigated using methylation-specific polymerase chain reaction, and recruitment of methyl binding proteins was studied using the chromatin immunoprecipitation assay. Mutation analysis was conducted using the QuikChange™ Site-Directed Mutagenesis kit. The activity of miR-373 gene promoter constructs and targeting at MBD2-three prime untranslated region (3'UTR) by miR-373 were evaluated by a dual-luciferase reporter gene assay.
  
  
  RESULTS
  In hilar cholangiocarcinoma, miR-373 decreased and was closely associated with poor cell differentiation, advanced clinical stage, and shorter survival. The promoter-associated CpG island of miR-373 gene was hypermethylated and inhibited expression of miR-373. MBD2 was up-regulated and enriched at the promoter-associated CpG island of miR-373. Methylation-mediated suppression of miR-373 required MBD2 enrichment at the promoter-associated CpG island, and miR-373 negatively regulated MBD2 expression through targeting the 3'UTR.
  
  
  CONCLUSIONS
  MiR-373 behaves as a direct transcriptional target and negative regulator of MBD2 activity through a feedback loop of CpG island methylation.
authors.affiliation: Department of Biliary-pancreatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China. chenyongjun45@126.com
authors.forename: Yong-Jun
authors.initials: YJ
authors.lastname: Chen
authors.forename: Jian
authors.initials: J
authors.lastname: Luo
authors.forename: Guang-Yao
authors.initials: GY
authors.lastname: Yang
authors.forename: Kang
authors.initials: K
authors.lastname: Yang
authors.forename: Song-Qi
authors.initials: SQ
authors.lastname: Wen
authors.forename: Sheng-Quan
authors.initials: SQ
authors.lastname: Zou
mesh_terms: D020413:3' Untranslated Regions; D001483:Base Sequence; D001650:Bile Duct Neoplasms / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D018281:Cholangiocarcinoma / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D018899:CpG Islands; D019175:DNA Methylation / Q000235:genetics; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006500:Hepatic Duct, Common; D006801:Humans; D018285:Klatskin Tumor / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D008297:Male; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism*; D008875:Middle Aged; D008954:Models, Biological; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012334:RNA, Neoplasm / Q000235:genetics* / Q000378:metabolism*
chemical_list: D020413:3' Untranslated Regions; D004268:DNA-Binding Proteins; C489325:MBD2 protein, human; C527114:MIRN373 microRNA, human; D035683:MicroRNAs; D012334:RNA, Neoplasm