在支气管上皮细胞恶性转化过程中Smad7表达变化对TGF-βR、SMADs及STRAP蛋白的影响

Effect of Smad7 on the expression of TGF-βR,SMADs,and STRAP in the process of malignant transformation of human bronchial epithelial cells

目的研究永生化人支气管上皮细胞BEP2D恶性转化过程中,作为Sm ad蛋白家族的抑制分子,Sm ad7对TGF-βR、R Sm ads及STRAP蛋白的表达影响。方法培养BEP2D、BERP35T2细胞及稳定表达Sm ad7蛋白的细胞BS7(来源于BEP2D)、RS7(来源于BERP35T2),提取细胞蛋白,用W estern b lot方法比较稳定转染Sm ad7基因前后的BEP2D和BERP35T2细胞中TGF-βRⅠ、TGF-βRⅡ、Sm ad2/3、Sm ad4及STRAP蛋白表达差异。结果稳定转染Sm ad7基因后细胞中TGF-βRⅡ表达降低,Sm ad2和STRAP蛋白表达增高,Sm ad3、Sm ad4蛋白表达无变化。结论Sm ad7高表达导致TGF-β信号通路发生改变,其中TGF-βRⅡ表达降低,STRAP表达增高可能是诱使细胞发生恶性转化的机制之一。

Objective To analyze the effect of Smad7 on the expression of TGF-βR, R Smads and STRAP in the process of malignant transformation of immortalized human bronchial epithelial cells BEP2D. Methods Cells were cultured and protein were extracted from BEP2D, BERP35T2, BS7 and RS7 cells, then Western blotting was performed to examine the expression level of TGF-βR Ⅰ , TGF-βR Ⅱ , Smad2/3, Smad4 and STRAP. Results Stable transfection of Smad7 gene led to decreased expression of TGF-βR Ⅱ and increased expression of Smad2 and STRAP in both BEP2D and BERP35T2 cells. There were no changes in the expression of Smad3 and Smad4. Conclusion Overexpression of Smad7 leads to decreased expression of TGF-βR Ⅱ and increased expression of STRAP in BEP2D and BERP35T2 cells, which could be one of the mechanisms of the malignant transformation of BEP2D cells.