데옥시콜릭산에 의한 HT-29 대장상피세포의 신호전달-NF-Κb와 Interleukin-8의 역할-

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-kB) activation and IL-8 expression, and tauroursodeoxycholic acid (TUDC) inhibits this signaling in HT-29 cells. Methods: After DCA treatments, time courses of NF-kB binding activity were determined by electrophoretic mobility shift assay (EMSA). Also, we performed Western blotting of IkBα to confirm NF-kB 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-kB, 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-kB binding complexes from 30 min to 8 hr and degradation of IkBα. The secretions of IL-8 were increased with DCA (50~200 μM) treatment in a time and dose-dependent manner. Pre-incubation of the cells with TUDC (0.1~10 μM) 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-kB activation and IL-8 expression, and DCA-induced NF-kB independent IL-8 expression is inhibited by TUDC.