PTEN induces apoptosis and up-regulates p53 expression in HepG2 cells.
- Author:
Zhi-Fang YANG
1
;
Ji-Lin YI
;
Xing-Rui LI
;
Da-Xing XIE
;
Xiao-Feng LIAO
;
Xin MA
Author Information
- Publication Type:Journal Article
- MeSH: Apoptosis; drug effects; Carcinoma, Hepatocellular; genetics; pathology; Gene Expression Regulation, Neoplastic; Humans; Liver Neoplasms; genetics; pathology; PTEN Phosphohydrolase; genetics; Tumor Suppressor Protein p53; biosynthesis; genetics; Up-Regulation
- From: Chinese Journal of Hepatology 2004;12(12):745-748
- CountryChina
- Language:Chinese
-
Abstract:
OBJECTIVETo investigate the effects of tumor suppressor gene PTEN on apoptosis and protein expression of p53 in HepG2 cells, as well as to explore its mechanisms.
METHODSHepG2 cells were transfected with GFP plasmids containing wild-type PTEN or G129E-PTEN and C124A-PTEN in vitro. Both the expression of wild-type p53 and the phosphorylation of protein kinase B (PKB/Akt) and focal adhesion kinase (FAK) were detected by Western blotting. Flow cytometry and confocal microscopy were used to analyze apoptosis of the transfected cells.
RESULTSCompared with the control, the expression of phosphorylated FAK and phosphoylated Akt were down-regulated in HepG2 cells transfected with wild-type PTEN (-65%, -93%) and G129E-PTEN (-65%, -35%), whereas the apoptosis percentage increased to (19.8+/-1.2)% and (9.2+/-0.6)%, and p53 expression was up-regulated by 120% and 50%, respectively. However, in the cells transfected with C124A-PTEN, neither the phosphorylation of FAK and Akt nor the apoptosis percentage and p53 expression had changed.
CONCLUSIONPTEN can dephosphrylate FAK through its protein phosphatase activity, and suppress phosphorylation of Akt mainly through its lipid phosphatase activity. Consequently, it can induce apoptosis of HepG2 cells and up-regulate p53 expression.