[Benzo(a)pyrene induced changes of cyclin D1, CDK4 and E2F-1/4 expression in human embryo lung fibroblasts]

To establish Benzo (a) pyrene-treated human embryo lung fibroblasts (HELF), which were provided with some characteristics of transformed cells (T-HELF), and observe the changes of cyclin D, CDK4 and E2F-1/4 expression in T-HELF cells.

Using 200, 100, 50, 25, 5 and 1 micromol/L B(a)P treated HELF cells for 24 h. Using MTT detected the cytotoxicity of B(a)P. 100,200 micromol/L B(a)P was chosen for the treatment of HELF cells. HELF cells was treated with B(a)P three times. The identification of T-HELF was investigated. Changes of cell cycle and the expression of cyclin D1,CDK4 and E2F-1/4 were checked using the flow cytometer and Western blot analysis.

The survival rate of HELF cells treated with 25-200 micromol/L B(a)P was 78%-80%. 4 w after B(a)P treatment, cells were all dead in 200/mol/L groups. 6 w after 100 micromol/L B(a) P treatment, the morphological changes could be observed. 12 w after treatment, there were colonies of T-HELF cells in soft agar. In T-HELF cells, cyclin D1 expression was higher than normal HELF, and cell cycle progressed through G, to S without serum. There were not significant changes of CDK4 and E2F-1/4 expression in T-HELF cells compared with normal HELF.

The T-HELF was established. This model provided a potential tool for investigating the molecular mechanism of carcinogenesis of B(a)P. The higher expression of cyclin D1 may contribute to the cell cycle changes of T-HELF cells.