title: microRNA-145 in Barrett's oesophagus: regulating BMP4 signalling via GATA6.
abstract: OBJECTIVE
  Barrett's oesophagus (BE) is a metaplastic condition of the distal oesophagus which predisposes to oesophageal adenocarcinoma (EAC). It has been suggested that microRNAs (miRNAs) are involved in the process of development of BE and EAC; however, few functional miRNA data are available. The aim of the study was to perform a tissue-specific miRNA profile and, based on this, to examine the function of miRNA-145 in the oesophagus.
  
  
  METHODS
  miRNA expression profiling using microarray analysis in EAC, BE and normal squamous epithelium of the oesophagus (SQ) was performed and validated using real-time PCR in samples from 15 patients and in situ hybridisation in samples from 10 patients. The proliferative effect of miRNA-145 precursor transfection in the SQ (HET-1A) and BE cell line (BAR-T) was measured. Downstream targets of miRNA-145 were determined by analysing mRNA and protein expression from miRNA-145 transfected cells.
  
  
  RESULTS
  Three unique miRNA expression profiles were found in tissue from EAC, BE and SQ, which showed that miRNA-145 was upregulated in BE compared with EAC and SQ. Overexpression of miRNA-145 in HET-1A and BAR-T cells reduced cell proliferation and inhibited GATA6, BMP4 and SOX9 mRNA expression. Furthermore, altered BMP4 signalling was observed in vitro on miRNA-145 overexpression. These effects were blocked when cells were co-transfected with a miRNA-145 specific inhibitor. Additionally, BMP4 incubation of HET-1A cells altered miRNA-145 and GATA6 expression over time.
  
  
  CONCLUSIONS
  These results imply that miRNA-145 indirectly targets BMP4 via GATA6 and is potentially involved in the development of BE.
authors.affiliation: Department of Gastroenterology and Hepatology, F02.816, University Medical Center Utrecht, Heidelberglaan 100, 3508 GA Utrecht, The Netherlands. j.w.p.m.vanbaal-2@umcutrecht.nl
authors.forename: Jantine W P M
authors.initials: JW
authors.lastname: van Baal
authors.forename: Romy E
authors.initials: RE
authors.lastname: Verbeek
authors.forename: Pauline
authors.initials: P
authors.lastname: Bus
authors.forename: Matteo
authors.initials: M
authors.lastname: Fassan
authors.forename: Rhonda F
authors.initials: RF
authors.lastname: Souza
authors.forename: Massimo
authors.initials: M
authors.lastname: Rugge
authors.forename: Fiebo J W
authors.initials: FJ
authors.lastname: ten Kate
authors.forename: Frank P
authors.initials: FP
authors.lastname: Vleggaar
authors.forename: Peter D
authors.initials: PD
authors.lastname: Siersema
mesh_terms: D000328:Adult; D000368:Aged; D001471:Barrett Esophagus / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D055415:Bone Morphogenetic Protein 4 / Q000235:genetics / Q000378:metabolism*; D005260:Female; D050993:GATA6 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D006801:Humans; D017403:In Situ Hybridization; D008297:Male; D035683:MicroRNAs / Q000378:metabolism*; D008875:Middle Aged; D040081:Protein Array Analysis; D060888:Real-Time Polymerase Chain Reaction; D012494:Sampling Studies; D015398:Signal Transduction / Q000235:genetics
chemical_list: C525809:BMP4 protein, human; D055415:Bone Morphogenetic Protein 4; D050993:GATA6 Transcription Factor; C494759:GATA6 protein, human; C541010:MIRN145 microRNA, human; D035683:MicroRNAs