【摘要】 目的:探讨组蛋白去乙酰化酶抑制剂曲古抑菌素(trichostatin A,TSA)与肿瘤坏死因子α(TNF-α)分别或联合作用于人类单核细胞白血病细胞株U937细胞前后,IκB-α蛋白的表达变化及其在NF-κB激活过程中的作用。方法:分别将TSA、TNF-α单独或联合作用于U937细胞,用免疫印迹法及荧光显微镜检测NF-κB/P65蛋白在该细胞中的表达及定位的变化;流式细胞术和免疫印迹法分析IκB-α蛋白表达的变化。结果:①荧光显微镜观察:分别作用45min后,NF-κB/P65蛋白分布于对照组及TSA处理组的细胞浆;而TNF-α处理组胞浆、胞核中均可见P65蛋白分布;TSA+TNF-α联合处理组仅胞浆表达P65蛋白。免疫印迹结果同样证实,作用相同时间后,TNF-α处理组细胞核表达P65蛋白,TSA+TNF-α联合处理组细胞核内P65蛋白表达较前者明显减少;②流式细胞术结果表明,经相同时间处理后,TSA+TNF-α联合处理组的IκB-α蛋白平均荧光强度较TNF-α处理组明显增高(P<0.05);免疫印迹结果也显示,作用45min后,TNF-α处理组细胞IκB-α蛋白表达较对照组明显降低,TSA+TNF-α联合处理组细胞IκB-α的表达较前者明显增高,但在作用2h后二者IκB-α蛋白表达差异无显著性。结论:TSA能部分抑制TNF-α诱导的U937细胞IκB-α的降解,从而抑制NF-κB的激活。TSA有可能通过影响NF-κB信号途径发挥抗肿瘤作用。更多还原

【Abstract】 OBJECTIVE To investigate the effect of trichostatin A,one kind of HDAC inhibitors,on expression of IκB-α induced by TNF-α and activation of NF-κB in U937 cells.METHODS U937 cells were treated with TSA,TNF-α respectively or with both,the protein expression and subcellular localization of NF-κB/p65 were observed by western blot and fluorescence microscopy respectively;the expression and degradation of IκB-α were investigated through by flow cytometry and western blot.RESULTS ①Under fluorescence microscopy,NF-κB/p65 was only localized in cytoplasm of empty control and group-treated with TSA for 45 min,p65 was localized in nucleus of U937 cells treated with TSA and TNF-α,while it was expressed in both cytoplasm and nucleus of cells treated with TNF-α.Western blot also showed the same result:TNF-α-treated group cells nuclears expressed much more p65 protein than those treated with TNF-α plus TSA for 45 min.②After being treated with TSA and TNF-α for 45 min,the protein expression of IκBα in U937 cells detected by flow cytometry was stronger than those only treated with TNF-α(P<0.05).Through Western blot,it was found that IκB-α expression was fewer in TNF-α-treated group compared to control;which was obviously enhanced in group treated with TSA plus TNF-α than that treated with TNF-α for 45 min,but it was no differences between them after being treated for 2 h.CONCLUSION TSA can partially inhibit degradation of IκB-α induced by TNF-α and NF-κB activation in U937 cells.TSA can work through NFκB signal pathway against tumor,which can be a target of TSA for cancer therapy.更多还原