title: In oesophageal squamous cells, nitric oxide causes S-nitrosylation of Akt and blocks SOX2 (sex determining region Y-box 2) expression.
abstract: Barrett's metaplasia might develop if GORD causes oesophageal squamous cells to convert into columnar cells. Acid and bile exposures upregulate columnar differentiation genes like CDX2 in oesophageal squamous cells, but it is not known if such exposures downregulate squamous differentiation genes like SOX2. In addition to acid and bile, patients with GORD also have high oesophageal concentrations of nitric oxide (NO). This study aims to determine how acid, bile salts and NO affect genes that influence oesophageal cell phenotype.
  
  
  
  Oesophageal squamous cells from patients with Barrett's oesophagus were exposed to acidic bile salts or NOC-9 (an NO donor). SOX2, p63 (squamous transcription factor) and CDX2 mRNAs were measured by quantitative RT-PCR. SOX2 and its regulatory Akt pathway proteins were evaluated by western blotting. S-nitrosylation by NO was blocked by dithiothreitol. Immunohistochemistry for SOX2 was performed on the oesophagus of rats with surgically induced GORD which were fed diets with and without nitrite supplementation.
  
  
  
  In oesophageal squamous cells, NO profoundly decreased SOX2 protein and caused a significantly greater decrease in SOX2 mRNA than did acidic bile salts. NO also decreased p63 and increased CDX2 expression. NO caused S-nitrosylation of Akt, blocking its phosphorylation. Akt pathway inhibition by LY294002 or Akt siRNA reduced SOX2 mRNA. Rats fed with nitrite-supplemented diets exhibited weaker SOX2 oesophageal staining than rats fed with normal diets.
  
  
  
  In oesophageal squamous cells, NO blocks SOX2 expression through Akt S-nitrosylation. NO also increases CDX2 and decreases p63 expression. By triggering molecular events preventing squamous differentiation while promoting intestinal differentiation, NO might contribute to Barrett's pathogenesis.
authors.affiliation: Esophageal Diseases Center, VA North Texas Health Care System and the University of Texas Southwestern Medical Center, Dallas, Texas, USA Departments of Medicine, VA North Texas Health Care System and the University of Texas Southwestern Medical Center, Dallas, Texas, USA Division of Gastroenterology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Asanuma
authors.affiliation: Esophageal Diseases Center, VA North Texas Health Care System and the University of Texas Southwestern Medical Center, Dallas, Texas, USA Departments of Medicine, VA North Texas Health Care System and the University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Huo
authors.affiliation: Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Agoston
authors.initials: A
authors.lastname: Agoston
authors.affiliation: Esophageal Diseases Center, VA North Texas Health Care System and the University of Texas Southwestern Medical Center, Dallas, Texas, USA Departments of Medicine, VA North Texas Health Care System and the University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Xi
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Esophageal Diseases Center, VA North Texas Health Care System and the University of Texas Southwestern Medical Center, Dallas, Texas, USA Departments of Medicine, VA North Texas Health Care System and the University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Chunhua
authors.initials: C
authors.lastname: Yu
authors.affiliation: Esophageal Diseases Center, VA North Texas Health Care System and the University of Texas Southwestern Medical Center, Dallas, Texas, USA Department of Pediatrics, Children's Medical Center and the University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Edaire
authors.initials: E
authors.lastname: Cheng
authors.affiliation: Esophageal Diseases Center, VA North Texas Health Care System and the University of Texas Southwestern Medical Center, Dallas, Texas, USA Departments of Medicine, VA North Texas Health Care System and the University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Qiuyang
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Esophageal Diseases Center, VA North Texas Health Care System and the University of Texas Southwestern Medical Center, Dallas, Texas, USA Departments of Medicine, VA North Texas Health Care System and the University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Kerry B
authors.initials: KB
authors.lastname: Dunbar
authors.affiliation: Esophageal Diseases Center, VA North Texas Health Care System and the University of Texas Southwestern Medical Center, Dallas, Texas, USA Department of Surgery, VA North Texas Health Care System and the University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Thai H
authors.initials: TH
authors.lastname: Pham
authors.affiliation: Esophageal Diseases Center, VA North Texas Health Care System and the University of Texas Southwestern Medical Center, Dallas, Texas, USA Departments of Medicine, VA North Texas Health Care System and the University of Texas Southwestern Medical Center, Dallas, Texas, USA The Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: David H
authors.initials: DH
authors.lastname: Wang
authors.affiliation: Division of Gastroenterology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
authors.forename: Katsunori
authors.initials: K
authors.lastname: Iijima
authors.affiliation: Division of Gastroenterology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
authors.forename: Tooru
authors.initials: T
authors.lastname: Shimosegawa
authors.affiliation: Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Robert D
authors.initials: RD
authors.lastname: Odze
authors.affiliation: Esophageal Diseases Center, VA North Texas Health Care System and the University of Texas Southwestern Medical Center, Dallas, Texas, USA Departments of Medicine, VA North Texas Health Care System and the University of Texas Southwestern Medical Center, Dallas, Texas, USA The Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Spechler
authors.affiliation: Esophageal Diseases Center, VA North Texas Health Care System and the University of Texas Southwestern Medical Center, Dallas, Texas, USA Departments of Medicine, VA North Texas Health Care System and the University of Texas Southwestern Medical Center, Dallas, Texas, USA The Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Rhonda F
authors.initials: RF
authors.lastname: Souza
mesh_terms: D000818:Animals; D001471:Barrett Esophagus / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D001647:Bile Acids and Salts / Q000378:metabolism; D000071616:CDX2 Transcription Factor / Q000378:metabolism*; D002454:Cell Differentiation; D002460:Cell Line; D004195:Disease Models, Animal; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology; D004947:Esophagus / Q000473:pathology; D005764:Gastroesophageal Reflux / Q000150:complications / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D055748:SOXB1 Transcription Factors / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D014226:Triazenes / Q000378:metabolism*
chemical_list: D001647:Bile Acids and Salts; D000071616:CDX2 Transcription Factor; C491270:CDX2 protein, human; D012333:RNA, Messenger; C527782:SOX2 protein, human; D055748:SOXB1 Transcription Factors; D014226:Triazenes; C099612:NOC 9; D009569:Nitric Oxide
keywords: BARRETT'S METAPLASIA; GASTROESOPHAGEAL REFLUX DISEASE; NITRIC OXIDE