| 霍艳英,张开泰,李邦印,段瑞峰,徐勤枝,胡迎春,项晓琼,李刚,吴德昌.辐射诱发BEP 2 D恶性转化中Smad 7对TGF-β/SMADs信号通路的调控[J].中华放射医学与防护杂志,2003,23(5):311-313 |
| 辐射诱发BEP 2 D恶性转化中Smad 7对TGF-β/SMADs信号通路的调控 |
| Regulation of Smad 7 gene on TGF-β/SMADs-mediated signal transduction pathway in the process of malignant transformation |
| 投稿时间：2003-01-10 |
| DOI： |
| 中文关键词: Smad7 TGF-β 信号转导通路 恶性转化 |
| 英文关键词:Smad 7 TGF-β Signal transduction pathway Malignant transformation |
| 基金项目:国家重点基础研究发展规划973项目(G1998051207) |
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| 全文下载次数: 1964 |
| 中文摘要: |
| 目的 研究BEP2D细胞经辐射诱发恶性转化过程中,作为SMAD蛋白家族的抑制分子,Smad7对TGF-β/SMAD介导信号通路的调控。方法 用Northern blot检测TGF-β刺激之后,永生化BEP2D细胞及辐射诱发恶性转化的BERP35T2细胞中Smad7mRNA的表达水平。人工合成SMAD结合元件(SBE)重复序列,同报告基因碱性磷酸酶融合。构建好的载体同Smad7真核表达载体共转染,TGF-β刺激,通过报告基因的表达丰度来检测Smad7对TGF-β/SMADs介导的信号通路的调控。结果 Northern杂交结果表明,永生化细胞Smad7基因对TGF-β刺激的应答正常,恶性化细胞的应答降低。基因转染的结果表明,永生化细胞中SBE的基础活性较恶性化细胞高;TGF-β刺激之后,永生化细胞中SBE活性显著增强,恶性化细胞变化不明显;同Smad7真核表达载体共转染之后,两种细胞中SBE活性均显著降低。结论 在辐射诱发细胞发生恶性转化过程中,Smad7基因对TGF-β信号通路的反馈调节作用发生紊乱,使TGF-β信号通路持续处于抑制状态,TGF-β对细胞的负性调控作用减弱,细胞进一步向恶性化发展。 |
| 英文摘要: |
| Objective To analyze the regulating effect of Smad 7 gene on TGF-β/SMADs-mediated signal transduction pathway in the process of malignant transformation of immortalized human bronchial epithelial cells BEP2D. Methods Northern blot was used to examine the responsiveness of Smad 7 gene to TGF-β 1 in BEP2D cell line and its malignantly transformed BERP35T2 cell line cells.SBE4s containing four tandem repeats of an 8-bp palindromic consensus Smad-binding elements were ligated to multiple clone sites of pTAL-SEAP,a reporter vector which fused with alkaline phosphatase gene.Transient transfection was performed to investigate the regulation of Smad 7 on TGF-β/SMAD-mediated signal pathway. Results Northern blot results showed that when treated with TGF-β1,expression of Smad 7 gene was up-regulated rapidly in BEP2D cells,reaching a major peak at 60 and then declining at 90 min;but in BERP35T2 cells,it was not obviously increased after that treatment.Transient transfection of SBE4-SEAP reporter vector into BEP2D and BERP35T2 cells showed that the basal activity of the reporter was higher in the former than in the latter.Transient co-transfection of full-length Smad 7 cDNA construct with SBE4-SEAP reporter vector led to decreased activity of the reporter.Furthermore,the responsiveness of SBE to TGF-β1 was more sensitive in BEP2D cells than in BERP35T2 cells. Conclusion In the process of malignant transformation of cells the disorder of Smad7 in negative feedback regulation of TGF-β signaling pathways leads to down-regulation of responsiveness of the cells to TGF-β1,and also weakens the negative modulation activity of TGF-β1 to cells.All these could contribute to further malignant transformation of these cells. |
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