SC58125 regulates TNF-α induced apoptosis in human colonic carcinoma cell line HT29 by inhibiting IκBα degrades

AIM:To investigate whether SC58125 synergizes with TNF-α to induce HT-29 cell apoptosis and study the possible molecular mechanism. METHODS:By using MTT,Hoechst 33342 staining and agarose gel electrophoresis,the effect of SC58125/TNF-α on the proliferation and apoptosis of HT-29 cell line was examined. The activity of caspase-3,the expression of IκBα,the phosphorylation level of IκBα,and the activation of NF-κB were measured after treatment with SC58125 by electrophoretic mobility shift assay and Western blotting.RESULTS:Both SC58125 and TNF-α exhibited cytotoxicity. The combination of the two reagents significantly reduced HT-29 cell viability in a dose-dependent manner. SC58125 and TNF-α co-treated cells showed induced nuclear condensation and fragmentation,and led to oligonucleosomal cleavage of genomic DNA,which was accompanied by the induction of caspase activity. IκBα levels were substantially decreased by the treatment of TNF-α. The degradation of IκBα was almost completely inhibited when SC58125 was added. NF-κB was activated in HT-29 cells after treatment with TNF-α,whereas pretreatment of HT-29 cells with SC58125 for 2 h,TNF-α induced NF-κB DNA binding was profoundly suppressed. CONCLUSION:SC58125 synergizes with TNF-α to inhibit cell growth and induces apoptosis in HT-29 cells,which may be mediated by activating caspase-3 and preventing degradation of IκBα.