title: Helicobacter pylori urease and flagellin alter mucin gene expression in human gastric cancer cells.
abstract: BACKGROUND
  Helicobacter pylori (Hp), which is one of the causative agents in human gastric adenocarcinoma, is known to interact with mucous gel and alter mucin gene expression. The aim of this work was to study, using an in vitro model of cell infection, the effects of urease, flagellin, and CagA virulence factors on the regulation of the four 11p15 mucin genes (MUC2, MUC5AC, MUC5B, and MUC6).
  
  
  METHODS
  KATO-III and AGS gastric cancer cells were infected for 1, 3 or 6 h with Hp wild-type strains (ATCC 43504, N6, and SS1) or corresponding isogenic mutants deficient for urease subunit B, flagellin subunit A, and CagA. mRNA levels of MUC2, MUC5B, MUC5AC and MUC6 were assessed by RT-PCR, and functional activity of their promoters was measured by transient transfection assays.
  
  
  RESULTS
  Infection of KATO-III cells with Hp wild-type strains resulted in an early (at 1 h) transient expression of MUC2, MUC5AC, and MUC6 mRNA concomitant with those of interleukin (IL)-1β, IL-8, and TNF-α cytokines. In these cells, the UreB(-) isogenic mutant induced strong activation of MUC5AC expression, and UreB-responsive elements were located in the -486/-1 region of the promoter. FlaA(-) and CagA(-) mutants had no effect on mucin gene mRNA levels in KATO-III cells. In AGS cells, Hp-responsive elements were identified in all promoters, and overexpression of NF-κB induced upregulation of MUC5AC promoter activity when infected with the UreB(-) isogenic mutant.
  
  
  CONCLUSIONS
  These results indicate that Hp infection of gastric cancer cells alters 11p15 mucin gene transcription and that MUC5AC downregulation is mediated by urease virulence factor.
authors.affiliation: Inserm, UMR837, JPARC, Team "Mucins, Epithelial Differentiation and Carcinogenesis", Bâtiment G. Biserte, Rue Polonovski, 59045, Lille Cedex, France.
authors.forename: Michaël
authors.initials: M
authors.lastname: Perrais
authors.forename: Christel
authors.initials: C
authors.lastname: Rousseaux
authors.forename: Marie-Paule
authors.initials: MP
authors.lastname: Ducourouble
authors.forename: René
authors.initials: R
authors.lastname: Courcol
authors.forename: Pascal
authors.initials: P
authors.lastname: Vincent
authors.forename: Nicolas
authors.initials: N
authors.lastname: Jonckheere
authors.forename: Isabelle
authors.initials: I
authors.lastname: Van Seuningen
mesh_terms: D015153:Blotting, Western; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D005408:Flagellin / Q000235:genetics / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic; D016481:Helicobacter Infections / Q000235:genetics* / Q000378:metabolism / Q000821:virology; D016480:Helicobacter pylori / Q000502:physiology; D006801:Humans; D055271:Mucin 5AC / Q000235:genetics* / Q000378:metabolism; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000821:virology; D014407:Tumor Cells, Cultured; D014510:Urease / Q000235:genetics / Q000378:metabolism*; D014774:Virulence
chemical_list: D016207:Cytokines; D055271:Mucin 5AC; D016328:NF-kappa B; D012333:RNA, Messenger; D005408:Flagellin; D014510:Urease