TGF-β-activated SMAD3/4 complex transcriptionally upregulates N-cadherin expression in non-small cell lung cancer
2015-04-09 10:00点击:338次发表评论
作者:Yang, H., Wang, L., Zhao, J., Chen, Y., Lei, Z., Liu, X., Xia, W., Guo, L., Zhang, H.-T.
机构: 苏州大学医学院苏州大学癌症分子遗传学实验室
期刊: LUNG CANCER2015年3月3期87卷

Objectives: Epithelial-mesenchymal transition (EMT) is a key process in early stage of cancer metastasis. TGF-β-mediated EMT is characterized by repression of E-cadherin and induction of N-cadherin (CDH2) in various cancers. Although many investigations have focused on the regulation of E-cadherin expression, the transcription-mediated events that directly induce N-cadherin expression in TGF-β-induced EMT are not fully clear. Here, we mainly focus on non-small cell lung cancer (NSCLC) cells, in which expression of CDH2 can be activated upon TGF-β stimulation, to investigate the underlying mechanisms of CDH2 expression regulation. Materials and methods: Western blot analysis, real-time quantitative reverse transcriptase PCR, luciferase reporter gene assays, RNA interference and in vivo chromatin immunoprecipitation (ChIP) assay were performed on human NSCLC cell lines A549 and SPC-A1. Twenty-six paired NSCLC tissues and adjacent noncancerous lung tissues were collected. Results: Luciferase reporter assay revealed that a functional TGF-β-response element was located at position -1078 to -891 in the CDH2 promoter region. Furthermore, in vivo ChIP experiment indicated that TGF-β-activated SMAD3/4 complex was directly recruited to CDH2 promoter region (-1078 to -891). Upon TGF-β1 stimulation, knockdown of SMAD3 or/and SMAD4 led to a significant reduction in CDH2 promoter activity, and silencing of SMAD3 or SMAD4 significantly inhibited CDH2 mRNA and protein expression in A549 and SPC-A1 cells. In human NSCLC tissues, SMAD3 or SMAD4 mRNA level was positively correlated with CDH2 mRNA level, respectively. Conclusions: We found that TGF-β-activated SMAD3/4 complex may upregulate CDH2 expression by directly interacting with a specific SMAD-binding element in CDH2 promoter. Our findings provide insights into mechanisms underlying the transcriptional regulation of CDH2 expression in TGF-β-induced EMT and SMADs-based therapeutic strategies for NSCLCs.

通讯机构:Soochow University Laboratory of Cancer Molecular Genetics, Medical College of Soochow University, Suzhou, China
学科代码:呼吸病学 肿瘤学   关键词:TGF-β;转录性激活;SMAD3/4复合物;非小细胞;肺癌 ,中国作者重要发表 爱思唯尔医学网, Elseviermed
来源: Scopus
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