Ye Meng, Liu Bing-Ci, Shi Xiang-Lin, You Bao-Rong, Du Hong-Ju, Jia Xiao-Wei, Shen Fu-Hai
National Institute of Occupational Health and Poison Control, Chinese Center for Disease Control and Prevention, 29 Nanwei Road, Beijing 100050, China.
Biomed Environ Sci. 2008 Feb;21(1):30-6. doi: 10.1016/S0895-3988(08)60004-5.
To investigate the roles of the cyclin D1/CDK4 and E2F-1/4 pathways and compare their work patterns in cell cycle changes induced by different doses of B[a]P.
Human embryo lung fibroblasts (HELFs) were treated with 2 micromol/L or 100 micromol/L B[a]P which were provided with some characteristics of transformed cells (T-HELFs). Cyclin D1, CDK4 and E2F-1/4 expressions were determined by Western blotting. Flow cytometry was used to detect the distribution of cell cycle.
After B[a]P treatment, the proportion of the first gap (G1) phase cells decreased. CDK4 and E2F-4 expression did not change significantly. In 2 micromol/L treated cells, a marked overexpression of cyclin D1 and E2F-1 was observed. However, in T-HELFs overexpression was limited to cyclin D1 only, and no overexpression of E2F-1 was observed. The decreases of G1 phase in response to B[a]P treatment were blocked in antisense cyclin D1 and antisense CDK4 transfected HELFs (A-D1 and A-K4) and T-HELFs (T-A-D1 and T-A-K4). After 2 micromol/L B[a]P treatment, overexpression of E2F-1 was attenuated in A-D1, and E2F-4 expression was decreased significantly in A-K4. In T-A-D1 and T-A-K4, E2F-4 expression was increased significantly, compared with T-HELFs. The E2F-1 expression remained unchanged in T-A-D1 and T-A-K4.
Cyclin D1/CDK4-E2F-1/4 pathways work in different patterns in response to low dose and high dose B[a]P treatment. In HELFs treated with 2 micromol/L B[a]P, cyclin D1 positively regulates the E2F-1 expression while CDK4 negatively regulates the E2F-4 expression; however, in HELFs treated with 100 micromol/L B[a]P, both cyclin D1 and CDK4 negatively regulate the E2F-4 expression.
研究细胞周期蛋白D1/细胞周期蛋白依赖性激酶4（Cyclin D1/CDK4）和E2F-1/4信号通路的作用，并比较它们在不同剂量苯并[a]芘（B[a]P）诱导的细胞周期变化中的作用模式。
用2 μmol/L或100 μmol/L B[a]P处理人胚肺成纤维细胞（HELFs），使其具有转化细胞（T-HELFs）的一些特征。采用蛋白质免疫印迹法检测细胞周期蛋白D1、CDK4和E2F-1/4的表达。用流式细胞术检测细胞周期分布。
B[a]P处理后，第一间隙（G1）期细胞比例降低。CDK4和E2F-4表达无明显变化。在2 μmol/L处理的细胞中，观察到细胞周期蛋白D1和E2F-1明显过表达。然而，在T-HELFs中，过表达仅限于细胞周期蛋白D1，未观察到E2F-1过表达。在反义细胞周期蛋白D1和反义CDK4转染的HELFs（A-D1和A-K4）以及T-HELFs（T-A-D1和T-A-K4）中，B[a]P处理引起的G1期减少被阻断。2 μmol/L B[a]P处理后，A-D1中E2F-1的过表达减弱，A-K4中E2F-4表达明显降低。在T-A-D1和T-A-K4中，与T-HELFs相比，E2F-4表达明显增加。T-A-D1和T-A-K4中E2F-1表达保持不变。
细胞周期蛋白D1/CDK4-E2F-1/4信号通路在低剂量和高剂量B[a]P处理时作用模式不同。在2 μmol/L B[a]P处理的HELFs中，细胞周期蛋白D1正向调节E2F-1表达，而CDK4负向调节E2F-4表达；然而，在100 μmol/L B[a]P处理的HELFs中，细胞周期蛋白D1和CDK4均负向调节E2F-4表达。
