title: Taurodeoxycholate increases intestinal epithelial cell proliferation through c-myc expression.
abstract: BACKGROUND
  Bile salts have been shown to modulate gastrointestinal epithelial restitution, differentiation, and other functions. Prior studies have shown that the bile salt taurodeoxycholate increases cell migration after injury. The purpose of this experiment was to determine the effect that taurodeoxycholate has on intestinal epithelial cell growth, c-myc expression and function.
  
  
  METHODS
  IEC-6 or Caco-2 cells were treated with varying concentrations of taurodeoxycholate (.05 to 1 mmol/L) and proliferation determined. Apoptosis was measured by use of DNA fragmentation assay and nuclear staining. Cell phase was determined with propidium iodide flow cytometry. C-myc expression was determined by Northern and Western blot analysis, and c-myc function was inhibited by specific c-myc antisense.
  
  
  RESULTS
  There was no change in cell structure. Apoptosis was not induced. Six days after exposure to taurodeoxycholate, IEC-6 cell proliferation was significantly increased. Flow cytometry showed a significant increase in S-phase concentration and a significant decrease in G1-phase concentration of the cell cycle. Taurodeoxycholate also increased c-myc protein and mRNA expression, and inhibition of c-myc function prevented taurodeoxycholate-induced cell proliferation.
  
  
  CONCLUSIONS
  Exposure to physiological concentrations of the bile salt taurodeoxycholate increases intestinal epithelial cell proliferation. This effect is at least partially mediated through a c-myc-dependent mechanism. Bile salts can have a beneficial effect on the intestinal mucosa.
authors.affiliation: Department of Surgery, University of Maryland, Baltimore, Md 21201, USA.
authors.forename: Jon
authors.initials: J
authors.lastname: Yamaguchi
authors.forename: Alex
authors.initials: A
authors.lastname: Toledo
authors.forename: Barbara L
authors.initials: BL
authors.lastname: Bass
authors.forename: Francis A
authors.initials: FA
authors.lastname: Celeste
authors.forename: Jaladanki N
authors.initials: JN
authors.lastname: Rao
authors.forename: J-Y
authors.initials: JY
authors.lastname: Wang
authors.forename: Eric D
authors.initials: ED
authors.lastname: Strauch
mesh_terms: D000818:Animals; D018938:Caco-2 Cells; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002756:Cholagogues and Choleretics / Q000494:pharmacology*; D016373:DNA, Antisense / Q000494:pharmacology; D004847:Epithelial Cells / Q000166:cytology* / Q000502:physiology; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology; D006801:Humans; D007413:Intestinal Mucosa / Q000166:cytology* / Q000502:physiology; D007583:Jejunum / Q000166:cytology; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics*; D051381:Rats; D013657:Taurodeoxycholic Acid / Q000494:pharmacology*
chemical_list: D002756:Cholagogues and Choleretics; D016373:DNA, Antisense; D016271:Proto-Oncogene Proteins c-myc; D013657:Taurodeoxycholic Acid