title: Transformation of human liver L-O2 cells mediated by stable HBx transfection.
abstract: OBJECTIVE
  To explore the mechanism of hepatocarcinogenesis associated with the hepatitis B virus X protein (HBx), we investigated the role of HBx in transformation using human liver L-O2 cells stably transfected with HBx as a model.
  
  
  METHODS
  Plasmids encoding HBx were stably transfected into immortalized human liver L-O2 cells and rodent fibroblast NIH/3T3 cells. The expression of alfa-fetoprotein (AFP), c-Myc, HBx, and survivin in the engineered cells was examined by Western blotting. The malignant phenotype of the cells was demonstrated by anchorage-independent colony formation and tumor formation in nude mice. RNA interference assays, Western blotting, luciferase reporter gene assays and flow cytometry analysis were performed. The number of centrosomes in the L-O2-X cells was determined by gamma-tubulin immunostaining. The effect of HBx on the transcriptional activity of human telomerase reverse transcriptase (hTERT) and hTERT activity in L-O2-X cells and/or 3T3-X cells was detected by the luciferase reporter gene assay and telomerase repeat amplification protocol (TRAP).
  
  
  RESULTS
  Stable HBx transfection resulted in a malignant phenotype in the engineered cells in vivo and in vitro. Meanwhile, HBx was able to increase the transcription of the NF-kappaB, AP-1, and survivin genes and to upregulate the expression levels of c-Myc and survivin. Abnormal centrosome duplication and activated hTERT were responsible for the transformation.
  
  
  CONCLUSIONS
  Stable HBx transfection leads to genomic instability of host cells, which is responsible for hepatocarcinogenesis; meanwhile, transactivation by the HBx protein contributes to the development of hepatocellular carcinoma (HCC). The L-O2-X cell line is an ideal model for investigating the mechanism of HBx-mediated transformation.
authors: Department of Cancer Research, Key Laboratory of Molecular Microbiology and Technology of Ministry of Education, Institute for Molecular Biology, College of Life Sciences, Nankai University, Tianjin 300071, China.
authors: Wei-ying
authors: WY
authors: Zhang
authors: Na
authors: N
authors: Cai
authors: Li-hong
authors: LH
authors: Ye
authors: Xiao-dong
authors: XD
authors: Zhang
mesh_terms: D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000235:genetics*; D002460:Cell Line; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic; D018385:Centrosome / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins; D008099:Liver / Q000166:cytology*; D008113:Liver Neoplasms / Q000235:genetics*; D051379:Mice; D008819:Mice, Nude; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D041681:NIH 3T3 Cells; D000077022:Survivin; D019098:Telomerase / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D054334:Viral Regulatory and Accessory Proteins
chemical_list: C107489:BIRC5 protein, human; D051034:Inhibitor of Apoptosis Proteins; D008869:Microtubule-Associated Proteins; D016328:NF-kappa B; D000077022:Survivin; D015534:Trans-Activators; D018808:Transcription Factor AP-1; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein; D019098:Telomerase