EGF通过STAT5调控肺腺癌A549细胞中COX-2的机制  

Mechanisms of EGF Regulation of COX-2 Through the STAT5 Signaling Pathway in Human Lung Adenocarcinoma A549 Cells

作　　者：曹守强[1] 赵桂彬[1] 董庆[1] 韩敬泉[1] 辛衍忠[1] 闫宇博[1] 李吉尧[1] 崔键[1] 

机构地区：[1]哈尔滨医科大学附属第四医院胸外科,哈尔滨150001

出　　处：《中国肺癌杂志》2013年第4期169-176,共8页Chinese Journal of Lung Cancer

基　　金：黑龙江省卫生厅课题项目(No.2011-157)资助~~

摘　　要：背景与目的已有的研究表明COX-2在肺癌发生发展过程中起关键作用,它被一些细胞因子和生长因子所诱导产生,并受到JAK/STAT等信号通路的调控,抑制COX-2的表达能阻止肺癌的发展。本研究旨在探讨表皮生长因子(epidermal growth factor,EGF)在人肺腺癌A549细胞中对STAT5激活效应,以及STAT5信号通路对COX-2调控机制。方法应用免疫荧光法及Western印迹法检测人肺腺癌A549细胞中EGF对STAT5的激活现象。分别用野生型STAT5(AdWT STAT5),STAT5显性负突变体(AdCMV5 Stat5a△740)以及STAT5 siRNA转染A549细胞,并用EGF对后两组转染细胞加以刺激,使STAT5及p-STAT5的表达发生变化,再用RT-PCR检测A549细胞中的COX-2mRNA表达。结果在体外A549细胞中STAT5无激活;EGF可以诱导STAT5的激活,促使磷酸化的STAT5穿梭入核;STAT5的激活是EGF诱导COX-2上调表达的必要条件;非磷酸化的STAT5可能通过非转录激活的途径参与了COX-2表达的调控。结论在A549细胞中STAT5可以通过磷酸化和非磷酸化两种途径来实现对COX-2的调控。Background and objective It has been proved that cyclooxygenase-2 （COX-2） is a key factor in lung cancer oncogenesis. COX-2 can be induced by a number of cytokines and growth factors and can be regulated by the JAK/ STAT signaling pathway. Inhibiting the expression of COX-2 can prevent the deVelopment of lung cancer. The aim fo this study is to investigate whether the epidermal growth factor （EGF） can stimulate the signal transducers and activators of transcription 5 （STATS） as well as to discover the effects of the STATS signaling pathway on the COX-2 in human lung adenocarcinoma A549 cells. Methods The phenomenon of STATS activation stimulated by the EGF was assayed through immunofluorescence and Western blot. The adenovirus containing the wild-type （WT）-STATS （AdWT-STATS） plasmid, dominant-negative （DN）- STATS （Ad-CMVSStatSaA740） plasmid, and STATS siRNA were transfected into A549 cells. The latter two groups were stimulated using EGF. Reverse transcriptase polymerase chain reaction was used to detect the mRNA expression of COX-2. Results STATS was not activated in A549 ceils in vitro. EGF stimulation significantly increased the level of the p-STATS pro- tein and induces the shuttling of p-STATS from the cytoplasm into the nucleus. STATS activation was crucial for the COX-2 expression induced by the EGF. STATS was required for COX-2 expression, but can mediated the effects of the COX-2 expres- sion through pathways that were independent of transcriptional activation. Conclusion COX-2 expression is dependent on STATS phosphorylation. A second pathway does not require STATS phosphorylation.

关 键 词：STAT5 COX-2 肺肿瘤 A549 EGF 

分 类 号：R734.2[医药卫生—肿瘤]