Duan Yinong, Lyu Lei, Zhu Dandan, Wang Jianxin, Chen Jinling, Chen Liuting, Yang Chunzhao, Sun Xiaolei
Department of Pathogen Biology, School of Medicine, Nantong University, Nantong 226001, Jiangsu, People's Republic of China.
Laboratory Medicine Center, Affiliated Hospital of Nantong University, Nantong 226001, Jiangsu, People's Republic of China.
Oncotarget. 2017 Jun 20;8(25):40705-40712. doi: 10.18632/oncotarget.17248.
The p27 protein plays a critical role in cell cycle arrest. Our previous studies have demonstrated that recombinant P40 protein from Schistosoma japonicum (rSjP40) could induce G1 phase arrest of cell cycle. We, therefore, attempted to observe the effect of rSjP40 on p27 promoter activity in LX-2 cells and to explore its potential mechanisms in this study. Using both Western blot and dual-luciferase reporter assay, we demonstrated that rSjP40 could enhance the expression of p27 in LX-2 cells. Results obtained using truncated fragments of p27 promoter showed that rSjP40 increased p27 promoter activity in LX-2 cells, mainly via some transcription factors that bind to the -1740/-873 region of p27 promoter. Further studies confirmed that the enhancement of p27 promoter activity induced by rSjP40 was related to E2F1 in LX-2 cells. Transfection of siRNA of E2F1 could also restore the effect of rSjP40 on expression of p27 and partially on α-SMA. Therefore, our study provided further insights into the mechanism by which rSjP40 induces LX-2 cell cycle arrest at G1 phase and inhibits HSC activation. Our results provide basis for future study of the blocking effect of rSjP40 in liver fibrosis.
p27蛋白在细胞周期停滞中起关键作用。我们之前的研究表明，日本血吸虫重组P40蛋白（rSjP40）可诱导细胞周期的G1期停滞。因此，在本研究中，我们试图观察rSjP40对LX-2细胞中p27启动子活性的影响，并探讨其潜在机制。通过蛋白质免疫印迹法和双荧光素酶报告基因检测，我们证明rSjP40可增强LX-2细胞中p27的表达。使用p27启动子的截短片段获得的结果表明，rSjP40增加了LX-2细胞中p27启动子的活性，主要是通过一些与p27启动子的-1740 / -873区域结合的转录因子。进一步的研究证实，rSjP40诱导的p27启动子活性增强与LX-2细胞中的E2F1有关。转染E2F1的siRNA也可以恢复rSjP40对p27表达的影响，并部分恢复对α-SMA的影响。因此，我们的研究进一步深入了解了rSjP40诱导LX-2细胞周期在G1期停滞并抑制肝星状细胞激活的机制。我们的结果为未来研究rSjP40在肝纤维化中的阻断作用提供了依据。
