title: [cyclin D1/E2F pathways involved in cell cycle changes of human embryo lung fibroblasts induced by benzo(a)pyrene].
abstract: OBJECTIVE
  To investigate the roles of cyclin D1/CDK4-E2F-1/4 pathway in cell cycle changes of human embryo lung fibroblasts (HELF) induced by two different benzo(a)pyrene [B(a)P] treatment models.
  
  
  METHODS
  Two B(a)P treatment models: HELF were treated by 2 micromol/L B(a)P for 24 hours; HELF were treated by 100 micromol/L B(a)P three times 24 hours each and provide with some characteristics of transformed cells (T-HELF). Changes of cell cycle and the expression of cyclin D1, CDK4 and E2F-1/4 were checked using the flow cytometry and Western bolt analysis.
  
  
  RESULTS
  After 24 hours 2 microml/L B(a)P treatment, the HELFs in the G(1) phase was decreased. In HELF transfected with antisense cyclin Dl (A-Dl) and antisense CDK4 (A-K4), the expression of cyclin Dl and CDK4 blocked the cell cycle changes from the G(1) phase to the S phase induced by B(a)P. The overexpression of cyclin Dl and E2F-1 in HELF was induced by B(a)P. The E2F-1 overexpression in A-D1 induced B(a)P was inhibited. The E2F-4 expression was decreased and the CDK4 expression was increased significantly in A-K4 after B(a)P treatment. Most of T-HELF transfected with antisense cyclin Dl (T-A-Dl) and antisense CDK4 (T-A-K4) were retained in G(1) phase. The cyclin Dl expression in T-HELF was increased significantly compared with that in HELF. The E2F-4 expression in T-A-Dl and T-A-K4 was increased significantly compared with that in T-HELF.
  
  
  CONCLUSIONS
  B(a)P induces the cell cycle changes through cyclin D1/CDK4-E2F-1/4 pathway in HELF treated by 2 micromol/L B(a)P while it induces cell cycle changes through cyclin D1/CDK4-E2F-4 pathway in T-HELF.
authors.affiliation: National Institute of Occupation Health and Poison Control, Chinese Center for Disease Control and Prevention, Beijing 100050, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Ye
authors.forename: Bing-ci
authors.initials: BC
authors.lastname: Liu
authors.forename: Xiang-lin
authors.initials: XL
authors.lastname: Shi
authors.forename: Bao-rong
authors.initials: BR
authors.lastname: You
authors.forename: Hong-ju
authors.initials: HJ
authors.lastname: Du
authors.forename: Xiao-wei
authors.initials: XW
authors.lastname: Jia
authors.forename: Fu-hai
authors.initials: FH
authors.lastname: Shen
mesh_terms: D001564:Benzo(a)pyrene / Q000494:pharmacology*; D015153:Blotting, Western; D002453:Cell Cycle / Q000187:drug effects*; D002478:Cells, Cultured; D019938:Cyclin D1 / Q000096:biosynthesis*; D051358:Cyclin-Dependent Kinase 4 / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D050687:E2F1 Transcription Factor / Q000096:biosynthesis*; D050704:E2F4 Transcription Factor / Q000096:biosynthesis*; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D008168:Lung / Q000166:cytology / Q000196:embryology
chemical_list: D050687:E2F1 Transcription Factor; D050704:E2F4 Transcription Factor; D019938:Cyclin D1; D001564:Benzo(a)pyrene; D051358:Cyclin-Dependent Kinase 4