摘要
背景: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。目的:研究在辐射诱发细胞发生恶性转化过程中,Smad7过表达是否可通过抑制TGF-β信号转导通路来拮抗TGF-β对细胞的生长抑制效应。设计:自身对照前瞻性研究。地点和对象:研究在军事医学科学院放射医学研究所完成。实验对象为永生化人支气管上皮细胞BEP2D及辐射诱发恶性转化的人支气管上皮细胞BERP35T2。干预:以外源性TGF-β1作为刺激因子,用Northernblot检测永生化BEP2D及辐射诱发恶性转化的BERP35T2细胞中Smad7基因的表达水平;用Smad7真核表达载体PCISmad7.neo稳定转染永生化及恶性化的人支气管上皮细胞系,筛选G418抗性克隆,用Westernblot加以验证。用MTT法检测Smad7基因转染前后TGF-β对永生化及恶性化细胞的生长抑制效应。主要观察指标:Smad7转染前后BEP2D及BERP35T2细胞Smad7表达水平及TGF-β1作用于Smad7转染前后细胞的增殖能力变化。结果:辐射诱发恶性转化的BERP35T2细胞中Smad7表达水平高于永生化BEP2D细胞,相同浓度的TGF-β1对BERP35T2细胞的生长抑制效应较BEP2D细胞弱;
BACKGROUND: Escape of cells from inhibition of the growth and proliferation induced by transforming growth factor β(TGF β) may contribute to tumorigenesis. Smad7 is inhibitory Smads of TGF β signal transduction pathway and can prevent TGF β signaling. The disorder of Smad7 may lead to the perturbation of TGF β signal pathway. OBJECTIVE:To study the effect of Smad7 on TGF β signal transduction pathway and on TGF β mediated growth inhibition effects in the process of malignant transformation. DESIGN:The study was auto control and prospective. SETTING AND PARTICIPANTS:The experiment was carried out in the Insitute of Radiological Medicine,Academy of Milirary Medical Sclences Immortalization of human bronchial epithelial cell BEP2D and radiation induced neoplastic transformation of human bronchial epthelial cell BERP35T2 were studied. INTERVENTION:Expression of Smad7 mRNA in immortalized human bronchial epithelial cells BEP2D and radiation induced human tumorigenic bronchial epithelial cells BERP35T2 cells was determined by Northern blot.To investigate the further effects of Smad7 on TGF β mediated growth inhibition, BEP2D and BERP35T2 cells were stably transfected with a Smad7 expressing construct.The increased Smad7 levels were confirmed with western blot analysis in the Smad7 stable transfectants. TGF β mediated inhibition effect on BEP2D and BERP35T2 cells with or without stable transfection of Smad7 was measured with MTT. MAIN OUTCOME MEASURE:Smad7 expression level and the proliferation ability of BEP2D and BERP35T2 cells before and after stably transfection of Smad7 with or without the exogenous TGF β1. RESULTS:The Smad7 expression level in BERP35T2 cells was higher than that in BEP2D cells.The growth inhibitory effect on BERP35T2 was weaker than that on BEP2D cells at the same concentration of TGF β1.After transfection with Smad7 expressing vector, four Smad7 stably expressing cell clones were identified by western blot. In these cell clones, the TGF β1 mediated growth inhibition was partially abrogated. CONCLUSION:In the process of malignant transformation of human bronchial epithelial cells induced by α particles,the expression of Smad7 was up regulated.Overexpression of Smad7 could down regulate TGF β mediated growth inhibition effects on the growth of cells.
出处
《中国临床康复》
CSCD
2004年第5期974-976,共3页
Chinese Journal of Clinical Rehabilitation
基金
国家自然科学基金(30200329)~~
