Department of Thoracic-Cardio Surgery, First Affiliated Hospital of PLA General Hospital, Beijing 100048, China.
Biomed Res Int. 2014;2014:348728. doi: 10.1155/2014/348728. Epub 2014 Mar 18.
Nonsmall-cell lung cancer has a high mortality rate and poor prognosis. In the present study, we silenced EZH2 and explored the consequent cell cycle changes. The expression of cell-cycle-related proteins, including p53, p21, Cdc2, and cyclin B1, was detected with western blotting, and the cell cycle distribution was determined with flow cytometry. Inhibition of EZH2 expression changed the cell cycle distribution, in particular inducing G2/M arrest. Expression of Cdc2 and cyclin B1 was significantly decreased in A549 and HTB-56 cells after EZH2-siRNA treatment. In addition, p53 expression was increased by 21% and 18%, and p21 expression was increased by 31% and 23%, in A549 and HTB-56 cells, respectively, in the presence of EZH2-siRNA. This study clearly demonstrates that modulation of EZH2 expression with siRNA affects the cell cycle and the expression levels of p53 and p21, thereby changing cyclin B1 and Cdc2 expression and inducing G2/M arrest. These results may explain the observed antitumor activity of EZH2 silencing. Such explorations of the molecular mechanism of EZH2 will help us develop novel approaches to the diagnosis, treatment, and prevention of nonsmall-cell lung cancer.
非小细胞肺癌死亡率高，预后差。本研究沉默 EZH2 并探讨其对细胞周期的影响。通过 Western blot 检测细胞周期相关蛋白（包括 p53、p21、Cdc2 和 cyclin B1）的表达，通过流式细胞术检测细胞周期分布。抑制 EZH2 表达可改变细胞周期分布，特别是诱导 G2/M 期阻滞。EZH2-siRNA 处理 A549 和 HTB-56 细胞后，Cdc2 和 cyclin B1 的表达明显下调。此外，EZH2-siRNA 存在时，A549 和 HTB-56 细胞中 p53 表达分别增加 21%和 18%，p21 表达分别增加 31%和 23%。本研究清楚地表明，siRNA 调节 EZH2 表达影响细胞周期以及 p53 和 p21 的表达水平，从而改变 cyclin B1 和 Cdc2 的表达并诱导 G2/M 期阻滞。这些结果可能解释了观察到的 EZH2 沉默的抗肿瘤活性。对 EZH2 分子机制的探索将有助于我们开发非小细胞肺癌的诊断、治疗和预防的新方法。
