Wang Jing, Lv Xiao-Wen, Shi Jie-Ping, Hu Xiao-Song
Research Center for Eco-Environmental Sciences, The Chinese Academy of Sciences, Haidian District, Beijing 100085, China.
World J Gastroenterol. 2007 Feb 21;13(7):1129-34. doi: 10.3748/wjg.v13.i7.1129.
To investigate the effect of ceramide on the cell cycle in human hepatocarcinoma Bel7402 cells. Possible molecular mechanisms were explored.
[3- (4, 5)-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay, plasmid transfection, reporter assay, FACS and Western blotting analyses were employed to investigate the effect and the related molecular mechanisms of C2-ceramide on the cell cycle of Bel7402 cells.
C2-ceramide was found to inhibit the growth of Bel7402 cells by inducing cell cycle arrest. During the process, the expression of p21 protein increased, while that of cyclinD1, phospho-ERK1/2 and c-myc decreased. Furthermore, the level of CDK7 was downregulated, while the transcriptional activity of PPARgamma was upregulated. Addition of GW9662, which is a PPARgamma specific antagonist, could reserve the modulation action on CDK7.
Our results support the hypothesis that cell cycle arrest induced by C2-ceramide may be mediated via accumulation of p21 and reduction of cyclinD1 and CDK7, at least partly, through PPARgamma activation. The ERK signaling pathway was involved in this process.
研究神经酰胺对人肝癌Bel7402细胞细胞周期的影响，并探讨其可能的分子机制。
采用[3-(4,5)-二甲基噻唑-2-基]-2,5-二苯基四氮唑溴盐（MTT）法、质粒转染、报告基因检测、流式细胞术（FACS）及蛋白质免疫印迹（Western blotting）分析等方法，研究C2-神经酰胺对Bel7402细胞细胞周期的影响及其相关分子机制。
发现C2-神经酰胺可通过诱导细胞周期停滞来抑制Bel7402细胞的生长。在此过程中，p21蛋白表达增加，而细胞周期蛋白D1（cyclinD1）、磷酸化细胞外信号调节激酶1/2（phospho-ERK1/2）和c-myc的表达降低。此外，周期蛋白依赖性激酶7（CDK7）水平下调，而过氧化物酶体增殖物激活受体γ（PPARγ）的转录活性上调。添加PPARγ特异性拮抗剂GW9662可逆转对CDK7的调节作用。
我们的结果支持以下假说：C2-神经酰胺诱导的细胞周期停滞可能至少部分地通过激活PPARγ，使p21蓄积、细胞周期蛋白D1和CDK7减少来介导。细胞外信号调节激酶（ERK）信号通路参与了这一过程。
