title: [The roles of Ku80/p53 pathway in silica-induced cell cycle changes in human embryo lung fibroblasts].
abstract: OBJECTIVE
  To study the roles of Ku80/p53 pathway in silica-induced cell cycle changes in human embryo lung fibroblasts (HELF).
  
  
  METHODS
  Ku80 siRNA expression vectors were transfected into HELF by lipofectamine. Flow cytometry was used to detect the distributions of cell cycle and western blot assay was used to determine the expression level of Ku80, p53 and p21 proteins or the phosphorylation levels of p53-ser15 after cells were exposed to silica.
  
  
  RESULTS
  The expression levels of Ku80 protein increased in concentration-dependent and time-dependent manners after cells were exposed to silica. The proportion of G1 phases in H-NC cells (controls) decreased from 89.28% +/- 2.19% to 68.93% +/- 3.79% after exposure to silica, and the proportion of G1 phases in HELF cells (H-Ku80) decreased from 85.16% +/- 3.73% to 59.92% +/- 3.31% after exposure to silica (P<0.05). The expression levels of Ku80, p53 proteins or p21 proteins or phosphorylation level of p53-ser15 were obviously suppressed in H-Ku80, as compared with H-NC.
  
  
  CONCLUSIONS
  Ku80/p53 pathway plays a role in the cell cycle charges induced by silica in human embryo lung fibroblasts.
authors.affiliation: National Institute of Occupation Health and Poison Control, Chinese Center for Disease Control and Prevention, Beijing 100050, China.
authors.forename: Hai-feng
authors.initials: HF
authors.lastname: Liu
authors.forename: Feng-mei
authors.initials: FM
authors.lastname: Zhang
authors.forename: Bing-ci
authors.initials: BC
authors.lastname: Liu
authors.forename: Meng
authors.initials: M
authors.lastname: Ye
authors.forename: Xiao-wei
authors.initials: XW
authors.lastname: Jia
mesh_terms: D034961:Antigens, Nuclear / Q000378:metabolism*; D002453:Cell Cycle / Q000187:drug effects; D002478:Cells, Cultured; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D005434:Flow Cytometry; D006801:Humans; D000072200:Ku Autoantigen; D008168:Lung / Q000166:cytology / Q000378:metabolism; D010766:Phosphorylation; D011791:Quartz / Q000633:toxicity*; D015398:Signal Transduction; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
chemical_list: D034961:Antigens, Nuclear; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D004268:DNA-Binding Proteins; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D011791:Quartz; C000606509:Xrcc6 protein, human; D000072200:Ku Autoantigen