Down-regulation of PTEN expression due to loss of promoter activity in human hepatocellular carcinoma cell lines.
OBJECTIVE
To investigate the regulation of phosphatase and tensin homolog deleted on chromosome ten (PTEN) gene expression in human hepatocellular carcinoma (HCC) cell lines.


METHODS
The mRNA and protein levels of PTEN were detected by Northern blot and Western blot in HCC cell lines, respectively. Plasmids containing different fragments of PTEN promoter with Luciferase reporter were constructed and transiently transfected into HCC cell lines to study the promoter activity. DNA analysis and RT-PCR were performed to detect the mutation of PTEN promoter and PTEN cDNA.


RESULTS
Either protein or mRNA levels of PTEN in L02 cells (as a control) were significantly higher than that in HCC cell lines. The profile of PTEN promoter activity in 8 cell lines was closely correlated with levels of PTEN mRNA and PTEN protein. Furthermore, the sequence analysis of 8 cells lines showed no mutation in the region of PTEN promoter and PTEN cDNA.


CONCLUSIONS
PTEN expression is down-regulated in HCC cell lines probably due to loss of activity of PTEN promoter.
Ma
Dong-Zhu
DZ
Minstry of Health Key Laboratory of Glycocojugate Research, Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, 138 Yixueyuan Road, Shanghai 200032, China.
Xu
Zhen
Z
Liang
Yu-Long
YL
Su
Jian-Ming
JM
Li
Zeng-Xia
ZX
Zhang
Wen
W
Wang
Li-Ying
LY
Zha
Xi-Liang
XL
D006528:Carcinoma, Hepatocellular / Q000235:genetics*; D045744:Cell Line, Tumor; D015536:Down-Regulation; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics*; D051059:PTEN Phosphohydrolase; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D014158:Transcription, Genetic; D025521:Tumor Suppressor Proteins / Q000235:genetics*
D025521:Tumor Suppressor Proteins; D010744:Phosphoric Monoester Hydrolases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human