title: [Roles of p53 in the interaction of p21 and cell cycle proteins induced by benzo [a] pyrene].
abstract: OBJECTIVE
  To investigate the roles of p53 in the interaction of p21, cyclin D1 and CDK4 in human embryonic lung fibroblasts (HELFs) induced by benzo (a) pyrene.
  
  
  METHODS
  p53-H group (cells transfected with p53 small interference RNA plasmid, p53 siRNA) and HELF/CMV group (cells transfected with CMV vector) were treated with 2 micromol/L B [a] P for 24 h, and HELF/CMV + PFT-alpha group (HELF/CMV cells were treated with p53 chemical inhibitor, Pifithrin-alpha) was treated with 2 micromol/L B [a] P and 20 micromol/L PFT-alpha for 24 h. The above three groups set up control groups, respectively. Western blot assay was used to check the levels of p53, phosphorylated p53 at 20 site (p53-ser20), p21, cyclin D1 and CDK4. Immunoprecipitation assay was used to investigate the roles of p53 in the interaction of p21, cyclin D1 and CDK4.
  
  
  RESULTS
  After inhibition of p53 using PFT-alpha or siRNA, the high levels of p53, p53-ser 20 and p21 induced by B [a] P were markedly decreased. The change of cyclin D1 level was not obsevered and the level CDK4 was free of B [a] P. The combination of p21 and CDK 4 was increased after HELFs exposed to B [a] P, which can not be observed after inhibition p53. The combination of p21 and cyclin D1 was increased with or without the expression of p53 after HELFs exposed to B [a] P. The combination of cyclin D1 and CDK 4 was not affected by B [a] P.
  
  
  CONCLUSIONS
  p53 can affect the combination of p21 and CDK4 in HELFs induced by B [a] P.
authors.forename: Xia'nan
authors.initials: X
authors.lastname: Zhang
authors.forename: Yuegang
authors.initials: Y
authors.lastname: Li
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Jia
authors.forename: Bingci
authors.initials: B
authors.lastname: Liu
authors.forename: Meng
authors.initials: M
authors.lastname: Ye
mesh_terms: D001564:Benzo(a)pyrene / Q000633:toxicity*; D052160:Benzothiazoles; D002453:Cell Cycle; D018797:Cell Cycle Proteins; D019938:Cyclin D1; D051358:Cyclin-Dependent Kinase 4; D050759:Cyclin-Dependent Kinase Inhibitor p21; D005347:Fibroblasts; D006801:Humans; D008168:Lung; D034741:RNA, Small Interfering; D014050:Toluene / Q000031:analogs & derivatives; D014162:Transfection; D016159:Tumor Suppressor Protein p53
chemical_list: D052160:Benzothiazoles; D018797:Cell Cycle Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D034741:RNA, Small Interfering; D016159:Tumor Suppressor Protein p53; D019938:Cyclin D1; D001564:Benzo(a)pyrene; D014050:Toluene; C121565:pifithrin; D051358:Cyclin-Dependent Kinase 4