[PTEN induces anoikis through its phosphatase activity in hepatocellular carcinoma cells].
OBJECTIVE
To investigate the effect and mechanisms of tumor suppressor gene PTEN on the induction of anoikis of hepatocellular carcinoma SMMC-7721 cells.


METHODS
SMMC-7721 cells were transfected with GFP plasmids containing wild-type PTEN or phosphatase inactivating mutant PTEN (C124A-PTEN) in vitro; The PTEN expression and the phosphorylation levels of focal adhesion kinase (FAK) and protein kinase B (PKB/Akt) were detected by Western blotting; Flow cytometry assay and laser scanning confocal microscopy were used to analyze apoptosis in adherent and non-adherent cells.


RESULTS
Compared with the control, PTEN expression in the cells transfected with wild-type PTEN increased to 248%, while the phosphorylation level of FAK and Akt decreased 65.2% and 89.1%, respectively; and the anoikis percentage increased from 9.5% to 31.3%. In the cells transfected with C124A-PTEN, neither the phosphorylation of FAK and Akt nor the anoikis percentage had obviously changed, although the PTEN expression enhanced dramatically in comparison with the control.


CONCLUSIONS
Through its phosphatase activity, tumor suppressor gene PTEN can suppress the phosphorylation of FAK and Akt, and induce anoikis in hepatocellular carcinoma cells.
Yang
Zhi-fang
ZF
Department of Surgery, Tong Ji Hospital, Tong Ji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China. yangzhifang74@yahoo.com.cn
Yi
Ji-lin
JL
Li
Xing-rui
XR
Xie
Da-xing
DX
Liao
Xiao-feng
XF
D023102:Anoikis / Q000502:physiology*; D006528:Carcinoma, Hepatocellular / Q000473:pathology*; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000378:metabolism; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology*; D051059:PTEN Phosphohydrolase / Q000096:biosynthesis / Q000235:genetics*; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D010766:Phosphorylation; D014407:Tumor Cells, Cultured
D051416:Focal Adhesion Protein-Tyrosine Kinases; D010744:Phosphoric Monoester Hydrolases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human