title: Down-regulation of PTEN expression due to loss of promoter activity in human hepatocellular carcinoma cell lines.
abstract: 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.
authors.affiliation: 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.
authors.forename: Dong-Zhu
authors.initials: DZ
authors.lastname: Ma
authors.forename: Zhen
authors.initials: Z
authors.lastname: Xu
authors.forename: Yu-Long
authors.initials: YL
authors.lastname: Liang
authors.forename: Jian-Ming
authors.initials: JM
authors.lastname: Su
authors.forename: Zeng-Xia
authors.initials: ZX
authors.lastname: Li
authors.forename: Wen
authors.initials: W
authors.lastname: Zhang
authors.forename: Li-Ying
authors.initials: LY
authors.lastname: Wang
authors.forename: Xi-Liang
authors.initials: XL
authors.lastname: Zha
mesh_terms: 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*
chemical_list: D025521:Tumor Suppressor Proteins; D010744:Phosphoric Monoester Hydrolases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human