title: Nutlin-3-induced redistribution of chromatin-bound IFI16 in human hepatocellular carcinoma cells in vitro is associated with p53 activation.
abstract: OBJECTIVE
  Interferon-γ inducible protein 16 (IFI16), a DNA sensor for DNA double-strand break (DSB), is expressed in most human hepatocellular carcinoma cell (HCC) lines. In this study we investigated the re-localization of chromatin-bound IFI16 by Nutlin-3, a DNA damage agent, in HCC cells in vitro, and the potential mechanisms.
  
  
  METHODS
  Human HCC SMMC-7721 (wild-type TP53), Huh-7 (mutant TP53), Hep3B (null TP53) and normal fetal liver L02 cell lines were examined. DSB damage in HCC cells was detected via γH2AX expression and foci formation assay. The expression of IFI16 and IFNB mRNA was measured using RT-PCR, and subcellular localization and expression of the IFI16 protein were detected using chromatin fractionation, Western blot analysis, and fluorescence microscopy.
  
  
  RESULTS
  Treatment of SMMC-7721 cells with Nutlin-3 (10 μmol/L) or etoposide (40 μmol/L) induced significant DSB damage. In SMMC-7721 cells, Nutlin-3 significantly increased the expression levels of IFI16 and IFNB mRNA, and partially redistributed chromatin-bound IFI16 protein to the cytoplasm. These effects were blocked by pretreatment with pifithrin-α, a p53 inhibitor. Furthermore, Nutlin-3 did not induce ectopic expression of IFI16 protein in Huh-7 and Hep3B cells. Moreover, the association of IFI16 with chromatin and Nutlin-3-induced changes in localization were not detected in L02 cells.
  
  
  CONCLUSIONS
  Nutlin-3 regulates the subcellular localization of IFI16 in HCC cells in vitro in a p53-dependent manner.
authors.affiliation: 1] Department of Microbiology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu 610041, China [2] Department of Pathobiology and Immunology, Hebei University of Chinese Medicine, Shijiazhuang 050200, China [3] Key Laboratory of Immune Mechanism and Intervention on Serious Disease in Hebei Province, Hebei Medical University, Shijiazhuang 050017, China.
authors.forename: Xin-li
authors.initials: XL
authors.lastname: Shi
authors.affiliation: Department of Microbiology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu 610041, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Nephrology, The First Affiliated Hospital of Chengdu Medical College, Chengdu 610500, China.
authors.forename: Nan
authors.initials: N
authors.lastname: Mao
authors.affiliation: Department of Immunology, Hebei Medical University, Shijiazhuang 050017, China.
authors.forename: Jing-hua
authors.initials: JH
authors.lastname: Wu
authors.affiliation: Department of Microbiology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu 610041, China.
authors.forename: Lai-feng
authors.initials: LF
authors.lastname: Ren
authors.affiliation: Department of Microbiology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu 610041, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Yang
authors.affiliation: 1] Key Laboratory of Immune Mechanism and Intervention on Serious Disease in Hebei Province, Hebei Medical University, Shijiazhuang 050017, China [2] Department of Immunology, Hebei Medical University, Shijiazhuang 050017, China.
authors.forename: Xiao-lin
authors.initials: XL
authors.lastname: Yin
authors.affiliation: 1] Key Laboratory of Immune Mechanism and Intervention on Serious Disease in Hebei Province, Hebei Medical University, Shijiazhuang 050017, China [2] Department of Immunology, Hebei Medical University, Shijiazhuang 050017, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Wei
authors.affiliation: 1] Department of Microbiology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu 610041, China [2] State Key Laboratory of Oral Diseases, Sichuan University, Chengdu 610041, China.
authors.forename: Ming-yuan
authors.initials: MY
authors.lastname: Li
authors.affiliation: Department of Microbiology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu 610041, China.
authors.forename: Bao-ning
authors.initials: BN
authors.lastname: Wang
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000378:metabolism*; D002460:Cell Line; D045744:Cell Line, Tumor; D002843:Chromatin / Q000378:metabolism*; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology*; D008113:Liver Neoplasms / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism*; D010879:Piperazines / Q000494:pharmacology*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
chemical_list: D002843:Chromatin; D007093:Imidazoles; D009687:Nuclear Proteins; D010750:Phosphoproteins; D010879:Piperazines; D016159:Tumor Suppressor Protein p53; C076700:IFI16 protein, human; C482205:nutlin 3