Tong Jin-lu, Nie Fang, Ran Zhi-hua, Pan Chang-qing, Xu Xi-tao, Zhu Ming-ming, Xiao Shu-dong
Department of Gastroenterology, Renji Hospital, Shanghai Jiao Tong University, Shanghai, China.
Zhonghua Zhong Liu Za Zhi. 2009 Sep;31(9):646-50.
To investigate the cytotoxic effect of epigallocatechin gallate (EGCG) on human hepatocellular carcinoma cell line HepG2 cells and corresponding changes of TGF-beta1-Smad pathway.
The cytotoxic effect of EGCG on HepG2 cells was determined by MTT assay. Cell cycle and apoptosis rate were detected by flow cytometry. RT-PCR and luciferase assay were used to verify whether TGF-beta1-Smad signaling pathway is intact in HepG2. The mRNA expression of Smad 2, Smad3, Smad4 and Smad7 was detected by real-time PCR.
EGCG induced apoptosis in the HepG2 cells in a time- and concentration-dependent manner. The proportion of G(1) phase cells was increased gradually as the concentration increased. However, the percentage of cells in S phase was decreased gradually. Annexin V/PI assay demonstrated that early apoptosis increased as the concentration increased, and late apoptosis also increased, when treated with high-concentration EGCG. The intact TGF-beta1-Smad pathway was verified by luciferase assay and RT-PCR. There was no significant effect of EGCG on mRNA level of Smad 2, Smad 3, and Smad 4 in HepG2 cells, but downregulated mRNA level of Smad 7.
EGCG can reduce apoptosis in human hepatocellular carcinoma cell line HepG2 cells. The activation of TGF-beta1-Smad signaling pathway may be involved in its cytotoxicity mechanisms.
研究表没食子儿茶素没食子酸酯（EGCG）对人肝癌细胞系HepG2细胞的细胞毒性作用以及TGF-β1-Smad信号通路的相应变化。
采用MTT法检测EGCG对HepG2细胞的细胞毒性作用。通过流式细胞术检测细胞周期和凋亡率。运用RT-PCR和荧光素酶报告基因检测法验证TGF-β1-Smad信号通路在HepG2细胞中是否完整。采用实时PCR检测Smad 2、Smad3、Smad4和Smad7的mRNA表达。
EGCG以时间和浓度依赖性方式诱导HepG2细胞凋亡。随着浓度增加，G(1)期细胞比例逐渐升高，而S期细胞百分比逐渐降低。Annexin V/PI检测表明，随着浓度增加，早期凋亡增加，高浓度EGCG处理时晚期凋亡也增加。荧光素酶报告基因检测法和RT-PCR验证了TGF-β1-Smad信号通路完整。EGCG对HepG2细胞中Smad 2、Smad 3和Smad 4的mRNA水平无显著影响，但使Smad 7的mRNA水平下调。
EGCG可诱导人肝癌细胞系HepG2细胞凋亡。TGF-β1-Smad信号通路的激活可能参与其细胞毒性机制。
