EGCG影响NF-κB入核后的周期阻滞效应

Effects of EGCG on Cell Cycle Arrest by Regulating NF-κB Entering the Nucleus

目的观察表没食子儿茶素没食子酸酯(EGCG)调节肿瘤坏死因子-α(TNF-α)诱导的胃癌SGC-7901细胞核转录因子κB(NF-κB)入核后的周期阻滞效应。方法胃癌SGC-7901细胞分4组:空白对照组(常规培养换液)、TNF-α实验组(终浓度10 ng/mL的TNF-α,培养60 min)、EGCG组(终浓度为60μg/mL的EGCG作用24 h后再加终浓度10 ng/mL的TNF-α,培养60 min)、阳性对照药物组(NF-κB通路阻断剂吡咯啉烷二甲基硫脲终浓度100μmol/mL预处理细胞30 min后,再加终浓度10 ng/mL的TNF-α,培养60 min)。Westernblot方法观察EGCG作用前后NF-κB蛋白在胞浆内及核内的变化;流式细胞术检测EGCG调节NF-κB入核前后细胞周期分布的变化。结果EGCG 60μg/mL作用24 h可有效抑制NF-κB入核。TNF-α作为NF-κB入核促进剂可以明显促进SGC-7901细胞由G1期进入S期;EGCG或吡咯啉烷二甲基硫脲(PDTC),分别预处理SGC-7901细胞后,再以TNF-α处理细胞,结果呈现明显的G1期阻滞效应,且该效应呈浓度依赖性。结论EGCG能够抑制TNF-α诱导的NF-κB入核,并可能通过此机制发挥诱导细胞周期阻滞的作用。

Objective To investigate the effects of Epigallocatechin - 3 - gallate （EGCG） on cell cycle arrest by regulating NF - κB entering the nucleus. Methods The gastric cancer cells SGC -7901 were divided into four groups. The blank group was dealt with routine method. The TNF - α group was dealt with TNF -α of extreme concentration 10 ng/mL for 60 min. The EGCG group was dealt with EGCG of extreme concentration 60 μg/mL for 24 h, followed by TNF - α of extreme concentration 10 ng/mL for 60 min. The control group was dealt with pyrrolidine dithiocarbamate of extreme con- centration 100 μmol/mL for 30 min, followed by TNF - α of extreme concentration 10 ng/mL for 60 min . The disposition of NF - κB was detected by Western blot. The effect of EGCG on cell cycle arrest was analyzed by flow cytometry （ FCM ）. Results EGCG could actively suppress the entering of NF - κB to the nucleus by 60 μg/mL,24 h. FCM showed that TNF - α, as an activator of NF - κB, could significantly increase the percentages of G1 phase cell. When exposed to EGCG or PDTC ,the inductor of NF - κB before the TNF - α ,the percentages of G1 phase cells increased with a time - dependent manner. Conclusion EGCG could regulate the NF - κB/p65 ＇ s entering to the cell nucleus induced by TNF -α, and could significanlty induce cell cycle G1 phase arrest by this regulation.