title: miR-143 and miR-145 are downregulated in ulcerative colitis: putative regulators of inflammation and protooncogenes.
abstract: BACKGROUND
  miR-143 and miR-145 are believed to function as colon cancer tumor suppressors, as they inhibit colon cancer cell growth and are downregulated in sporadic colonic tumors. We speculated that miR-143 and miR-145 might also be downregulated and contribute to malignant transformation of colonic epithelium in longstanding ulcerative colitis (UC).
  
  
  METHODS
  Biopsies were obtained 20 cm proximal to the anus from individuals with quiescent UC and from normal controls. RNA and proteins were extracted and measured. miR-143 and miR-145 were quantified by real-time polymerase chain reaction (PCR) and miR-145 was also assessed by in situ hybridization. Putative targets of these miRNAs, K-RAS, API5, MEK-2 (miR-143), and IRS-1 (miR-145) were determined by western blotting. To assess the effects of miR-143 and miR-145 on these predicted targets, HCT116 and HCA-7 colorectal cancer cells were transfected with miR-143 and miR-145 and expression levels of these proteins were measured.
  
  
  RESULTS
  In UC, miR-143 and miR-145 were significantly downregulated 8.3-fold (3.4-20.1) (P < 0.0001) and 4.3-fold (2.3-7.8) (P < 0.0001), respectively, compared to normal colon. In contrast, IRS-1, K-RAS, API5, and MEK-2 were upregulated in UC, consistent with their assignments as targets of these miRNAs. Furthermore, transfected miR-143 and miR-145 significantly downregulated these proteins in HCT116 or HCA-7 cells.
  
  
  CONCLUSIONS
  Compared to normal colonic mucosa, in chronic UC miR-143 and miR-145 were significantly downregulated and their predicted targets, IRS-1, K-RAS, API5, and MEK-2 were upregulated. We postulate that loss of these tumor suppressor miRNAs predispose to chronic inflammation and neoplastic progression in IBD.
authors.affiliation: Section of Gastroenterology, Hepatology, and Nutrition, University of Chicago, Illinois, USA. jpekow@medicine.bsd.uchicago.edu
authors.forename: Joel R
authors.initials: JR
authors.lastname: Pekow
authors.forename: Urszula
authors.initials: U
authors.lastname: Dougherty
authors.forename: Reba
authors.initials: R
authors.lastname: Mustafi
authors.forename: Hongyan
authors.initials: H
authors.lastname: Zhu
authors.forename: Masha
authors.initials: M
authors.lastname: Kocherginsky
authors.forename: David T
authors.initials: DT
authors.lastname: Rubin
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Hanauer
authors.forename: John
authors.initials: J
authors.lastname: Hart
authors.forename: Eugene B
authors.initials: EB
authors.lastname: Chang
authors.forename: Alessandro
authors.initials: A
authors.lastname: Fichera
authors.forename: Loren J
authors.initials: LJ
authors.lastname: Joseph
authors.forename: Marc
authors.initials: M
authors.lastname: Bissonnette
mesh_terms: D000328:Adult; D015153:Blotting, Western; D016022:Case-Control Studies; D002908:Chronic Disease; D003093:Colitis, Ulcerative / Q000235:genetics* / Q000473:pathology; D003106:Colon / Q000378:metabolism / Q000473:pathology; D015536:Down-Regulation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D017403:In Situ Hybridization; D007249:Inflammation / Q000235:genetics*; D008297:Male; D035683:MicroRNAs / Q000235:genetics*; D008875:Middle Aged; D011519:Proto-Oncogenes; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D055815:Young Adult
chemical_list: C542359:MIRN143 microRNA, human; C541010:MIRN145 microRNA, human; D035683:MicroRNAs; D012333:RNA, Messenger