Korean J Gastroenterol.  2004 Mar;43(3):176-185.

Deoxycholic Acid-Induced Signal Transduction in HT-29 Cells: Role of NF-kappa B and Interleukin-8

• Lee DK
• Park SY
• Baik SK
• Kwon SO
• Chung JM
• Oh ES
• Kim HS

Abstract

BACKGROUND/AIMS: Deoxycholic acid (DCA) has been appeared to be an endogenous colon tumor promoter. In this study, we investigated whether DCA induces nuclear factor-kappa B (NF-kappa B) activation and IL-8 expression, and tauroursodeoxycholic acid (TUDC) inhibits this signaling in HT-29 cells. METHODS: After DCA treatments, time courses of NF-kappa B binding activity were determined by electrophoretic mobility shift assay (EMSA). Also, we performed Western blotting of I kappa B alpha to confirm NF-kappa B activation. Time and concentration courses of DCA-induced secretion of IL-8 were measured with ELISA in supernatants of cultured media from the cells. To evaluate the role of NF-kappa B, IL-8 levels were assessed after pretreatment with using phosphorothioate-modified anti-sense oligonucleotides (ODN). Moreover, DCA-induced secretions of IL-8 were measured after pretreatment with TUDC. RESULTS: DCA dose-dependently induced prominent NF-kappa B binding complexes from 30 min to 8 hr and degradation of I kappa B alpha. The secretions of IL-8 were increased with DCA (50~200 micro M) treatment in a time and dose-dependent manner. Pre-incubation of the cells with TUDC (0.1~10 micro M) for 2 hours caused significant decreases in DCA induced IL-8 secretion. However, transient transfection using p50 or p65 AS-ODN showed no effect on IL-8 secretion. CONCLUSIONS: DCA may play as a colonic tumor promoter through anti-apoptotic effect of NF-kappa B activation and IL-8 expression, and DCA-induced NF-kappa B independent IL-8 expression is inhibited by TUDC.

Keyword

Deoxycholic acid; HT-29 cells; NF-kappa B; Interleukin-8

MeSH Terms

Blotting, Western
Colonic Neoplasms
Deoxycholic Acid/*pharmacology
Dose-Response Relationship, Drug
Electrophoretic Mobility Shift Assay
English Abstract
HT29 Cells
Humans
Interleukin-8/*metabolism
NF-kappa B/*metabolism
Oligonucleotides, Antisense/pharmacology
Signal Transduction/*drug effects
Taurochenodeoxycholic Acid/*pharmacology
Trans-Activation (Genetics)/drug effects