Epigallocatechin gallate induces apoptosis in human hepatocellular carcinoma HepG2 cells via TGF/Smad signaling pathway.
- Author:
Jin-lu TONG
1
;
Fang NIE
;
Zhi-hua RAN
;
Chang-qing PAN
;
Xi-tao XU
;
Ming-ming ZHU
;
Shu-dong XIAO
Author Information
- Publication Type:Journal Article
- MeSH: Anticarcinogenic Agents; pharmacology; Apoptosis; drug effects; Catechin; analogs & derivatives; pharmacology; Cell Cycle; drug effects; Hep G2 Cells; Humans; RNA, Messenger; metabolism; Signal Transduction; Smad Proteins; genetics; metabolism; Smad7 Protein; genetics; metabolism; Transforming Growth Factor beta1; metabolism
- From: Chinese Journal of Oncology 2009;31(9):646-650
- CountryChina
- Language:Chinese
-
Abstract:
OBJECTIVETo investigate the cytotoxic effect of epigallocatechin gallate (EGCG) on human hepatocellular carcinoma cell line HepG2 cells and corresponding changes of TGF-beta1-Smad pathway.
METHODSThe 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.
RESULTSEGCG 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.
CONCLUSIONEGCG 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.