p53蛋白参与NGF诱导的PC12细胞周期阻滞

The Role of Protein p53 in Cell Cycle Arrest Induced by NGF in PC12 Cells

通过观察不同营养状况下NGF诱导PC12细胞发生周期阻滞过程中p53蛋白水平的变化,探讨p53在PC12细胞周期阻滞中可能的作用机制.用流式细胞术检测细胞周期;Westernblot检测p53和p21WAF1/CIP蛋白水平.结果显示1%FBS(FatalBovineSerum)和50μg/LNGF(NerveGrowthFactor)均可诱导PC12细胞发生细胞周期阻滞.在10%FBS+50μg/LNGF处理的细胞中,p53和p21WAF1/CIP1均增高,而使用MEK抑制剂U0126(10μmol/L)可以抑制这一增高.在1%FBS处理的细胞中,p53水平增高,p21WAF1/CIP1却未见明显增高;进而加入50μg/LNGF作用1h后,p53显著降低,6h后再次升高,并持续至24h.可见p53在50μg/LNGF和1%FBS诱导的细胞周期阻滞中均发挥作用,但作用机制可能不同.

To study the role of p53 in cell cycle arrest of PC12 cells, protein levels of p53 and p21WAF1/CIP1 were investigated in differentiated PC12 cells induced by 50 μg/L NGF with 10%FBS or 1%FBS. The cell cycle was determined by cytoflowmetry and the protein levels of p53 and p21WAF1/CIP1 were analyzed by Western blot. The results showed that either 50 μg/L NGF or serum reduction could induce the cell cycle arrest in PC12 cells. The levels of both p53 and p21WAF1/CIP1 were increased in cells exposed to 50 μg/L NGF with 10%FBS, but these changes were disrupted after the treatment of 10 μmol/L U0126, an inhibitor of MEK(MAP kinase kinase). p53 was also increased in response to 1%FBS, however, the increase of p53 was inhibited immediately following the treatment of 50 μg/L NGF, and restored 6 h later. Contrasted to p53, the changes of p21WAF1/CIP1 were not observed. It can be concluded that p53 was probably involved in the cell cycle arrest of PC12 cells induced by 50 μg/L NGF or serum reduction with different mechanisms.