摘要
背景与目的:细胞逃避转化生长因子-β(TGF-β)诱导的对细胞生长、增殖的抑制是许多肿瘤发生的一个重要机制。Smad7是TGF-β信号转导通路的抑制型Smads,它可阻断TGF-β信号在胞浆内的传导,其紊乱是TGF-β信号转导通路紊乱的机制之一。本研究旨在分析在细胞恶性转化过程中,Smad7基因表达是否发生紊乱,TGF-β1对Smad7基因的调控功能有无发生变化,以探索细胞发生恶性转化的原因。方法:培养BEP2D细胞及BERP35T-2细胞,于收获前60min和90min加入不同剂量的TGF-β1,提取细胞总RNA,分别以未加TGF-β1的细胞组作为对照,用Northernblot杂交比较两组细胞Smad7mRNA表达的差异以及细胞对TGF-β1细胞因子刺激的反应性。同时提取BEP2D及BERP35T-2细胞蛋白,用Westernblot方法比较两组细胞内源性TGF-β1表达的差异。结果:Smad7mRNA表达水平恶性转化细胞高于永生化细胞;加了TGF-β1细胞因子后,BEP2D细胞Smad7mRNA表达增高,BERP35T-2细胞表达水平改变不明显。而内源性TGF-β1的表达水平,BERP35T-2细胞稍高于BEP2D细胞。结论:Smad7在辐射致肺癌细胞系中的过表达及对TGF-β1应答的降低可能是辐射诱发肺癌发生的机制之一。
Background &Objective:Escape from transforming growth fac tor-β(TGF-β)-induced inhibition of growth and proliferation may contribute to tumorigenesis.Smad7is inhi bitory Smads of TGF-βs signal transduction pathway and prevents TGF-βsignaling.The disorder of Smad7may lead to the perturbation of TGF-βsignal pathway.In this study,The authors analyzed the expression of Smad7mRNA and the regulation of Sm ad7gene by TGF-β1in the process of malignant transformation of BEP2D c ells to investigate the mechanism of cells malignant transformation.Methods:Cells were cultured and stimulated with TG F-β1followed by RNA extraction.Purifi ed total RNA from TGF-β1treated cells and untreated controls and performed an expression analysis with a human Smad7-specific probe applyin g Northern blot.As a loading control for the Northern experiment ,the membrane was hybridized with a human glyceraldeh yde-3-phosphate dehydro-genase(GAPDH)probe.Proteins were extracted from BEP2D and BERP35T-2cells,then perform Weste rn blot to examine the expression level of TGF-β1.Results:Before stimulation with TGF-β1,the expression level of Smad7in th e BERP35T-2cells were higher than th at in the BEP2D cells.When stimulate d with TGF-β1,Smad7expression levels was upreg ulated evidently in BEP2D cells,but not significant in BERP35T-2cells.The expression level of endogenetic TGF-β1,BERP35T-2cells was a little higher than BEP2D cells.Conclusion:over expression of Smad7mRNA and down-re gulation of the cellsresponsiveness to TGF-β1in human lung cancer cell line which induced byα-particles should be one of the mechanism of radiation induced lung cancer.
出处
《癌症》
SCIE
CAS
CSCD
北大核心
2002年第2期117-121,共5页
Chinese Journal of Cancer
基金
国家重点基础研究发展规划973项目(G1998051207)
