SC58125抑制IκBα降解调节TNF-α诱导的HT29细胞凋亡

SC58125 modulates TNF-α-induced HT-29 cells apoptosis through inhibiting IκBα degradation

目的观察非甾体类抗炎药SC58125与TNFα是否具有协同诱导HT29细胞的凋亡作用,同时探讨其可能的分子机制。方法用MTT、琼脂糖凝胶电泳及流式细胞术,观察SC58125/TNFα对HT29细胞增殖与凋亡的影响;用EMSA及Westernblot检测转录因子NFκB的结合活性及IκBα的表达。结果SC58125与TNFα在抑制HT29细胞增殖及诱导其凋亡方面具有明显的协同作用,TNFα使HT29细胞生长受到明显抑制,DNA发生典型的“梯型”变化;SC58125可明显增强TNFα抑制细胞增殖和诱导细胞凋亡作用,使HT29细胞凋亡率从11.2%±1.1%增加到53.9%±2.1%。凋亡过程中伴随Caspase3活性的激活;经TNFα刺激后的HT29细胞,IκBα迅速降解,NFκB的结合活性大大提高;而加入SC58125后,IκBα降解及NFκB的结合活性均明显受到抑制。结论SC58125与TNFα在诱导HT29细胞的凋亡方面具有明显的协同作用,这可能与SC58125抑制IκBα降解和激活Caspase有关。

Aim To investigate whether SC58125 synergized with TNF-α to induce HT-29 cell apoptosis and study the possible molecular mechanism. Methods By using MTT, agarose gel electrophoresis and flow cytometry, we examined the effect of SC58125/TNF-α on cell proliferation and apoptosis in HT-29 cells. The activity of caspase-3 and the changes of IκBα and NF-κB were also measured after treatment with SC58125 by Electrophoretic mobility shift assay and Western blot. Results Both SC58125 and TNF-α exhibited cytotoxicity, the combination of the two agents significantly reduced HT-29 cell viability in a dose-dependent manner. TNF-α-treated cells showed oligonucleosomal cleavage of genomic DNA. SC58125 significantly enhanced the inhibition of cell proliferation and inducement of cell apoptosis of TNF-α,the apoptotic index was increased from 11.2%±1.1% to 53.9%±2.1%. SC58125/TNF-α-induced apoptosis of HT-29 cells was accompanied by the induction of caspases-3. IκBα levels were substantially decreased after treatment with TNF-α and the degradation of IκBα was almost completely inhibited when SC58125 was added in 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 inhibited. Conclusion SC58125 synergizes with TNF-α to inhibit cell growth and induce apoptosis in HT-29 cells, which may be mediated by activating caspases and preventing degradation of IκBα.