Wang Tao, Zhao Hui, Gao Hua, Zhu Changming, Xu Yao, Bai Liping, Liu Junbo, Yan Feng
Department of Gastrointestinal Surgery, The Affiliated Zhongshan Hospital of Xiamen University, Xiamen, Fujian 361004, P.R. China.
Institute of Gastrointestinal Oncology, Medical College of Xiamen University, Xiamen, Fujian 361004, P.R. China.
Exp Ther Med. 2018 Apr;15(4):3197-3202. doi: 10.3892/etm.2018.5853. Epub 2018 Feb 8.
The mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K) pathways are activated during pathogenesis of gastrointestinal stromal tumors (GISTs). Forkhead box protein O1 (FOXO1) is a transcription factor regulated by the MAPK and PI3K pathways and is associated with multiple metabolic reactions. The present study aims to investigate the association of FOXO1 with cell proliferation and apoptosis in the cell line, GIST-T1. Cell counting kit-8 assay revealed that cell growth was inhibited by the PI3K inhibitor, LY294002, and/or MAPK inhibitor, UO126. Western blotting demonstrated that the expression of p-FOXO1 and B-cell lymphoma 2 (Bcl2) were significantly reduced, whereas the expression of Bcl-2-associated X protein was significantly increased following treatment with LY294002 and/or UO126 (all P<0.05). However, no significant change was revealed in the level of total FOXO1. Flow cytometry revealed that apoptosis was significantly increased by the pathway inhibitors (P<0.05). Specifically, the proportion of cells in the G1 phase was increased whereas the proportion in the S phase was reduced. The changes of protein expression and cell apoptosis were more evident in the LY294002 + UO126 group than in either single-inhibitor group. The results indicated that FOXO1 was able to affect cell proliferation, apoptosis and the cell cycle of GISTs. The regulation of FOXO1 was part of the PI3K and MAPK signaling network, while this regulation was mostly activated by phosphorylation of FOXO1.
丝裂原活化蛋白激酶（MAPK）和磷脂酰肌醇3激酶（PI3K）通路在胃肠道间质瘤（GISTs）发病过程中被激活。叉头框蛋白O1（FOXO1）是一种受MAPK和PI3K通路调控的转录因子，与多种代谢反应相关。本研究旨在探讨FOXO1与GIST-T1细胞系中细胞增殖和凋亡的关系。细胞计数试剂盒-8检测显示，PI3K抑制剂LY294002和/或MAPK抑制剂UO126可抑制细胞生长。蛋白质印迹法表明，用LY294002和/或UO126处理后，p-FOXO1和B细胞淋巴瘤2（Bcl2）的表达显著降低，而Bcl-2相关X蛋白的表达显著增加（均P<0.05）。然而，总FOXO1水平未发现显著变化。流式细胞术显示，通路抑制剂可显著增加细胞凋亡（P<0.05）。具体而言，G1期细胞比例增加，而S期细胞比例降低。LY294002 + UO126组的蛋白质表达和细胞凋亡变化比单一抑制剂组更明显。结果表明，FOXO1能够影响GISTs的细胞增殖、凋亡和细胞周期。FOXO1的调节是PI3K和MAPK信号网络的一部分，而这种调节主要通过FOXO1的磷酸化激活。
