Format

Send to

Choose Destination
Lung Cancer. 2015 Mar;87(3):249-57. doi: 10.1016/j.lungcan.2014.12.015. Epub 2015 Jan 5.

TGF-β-activated SMAD3/4 complex transcriptionally upregulates N-cadherin expression in non-small cell lung cancer.

Author information

1
Soochow University Laboratory of Cancer Molecular Genetics, Medical College of Soochow University, Suzhou 215123, China; Suzhou Key Laboratory for Molecular Cancer Genetics, Suzhou 215123, China.
2
Department of Thoracic and Cardiovascular Surgery, The First Affiliated Hospital of Soochow University, Medical College of Soochow University, Suzhou 215006, China.
3
Department of Thoracic and Cardiovascular Surgery, The Second Affiliated Hospital of Soochow University, Medical College of Soochow University, Suzhou 215004, China.
4
Department of Pathology, The Second Affiliated Hospital of Soochow University, Medical College of Soochow University, Suzhou 215004, China.
5
Soochow University Laboratory of Cancer Molecular Genetics, Medical College of Soochow University, Suzhou 215123, China; Suzhou Key Laboratory for Molecular Cancer Genetics, Suzhou 215123, China. Electronic address: htzhang@suda.edu.cn.

Abstract

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.

KEYWORDS:

CDH2; EMT; NSCLC; SMAD; TGF-β; Transcription regulation

PMID:
25595426
DOI:
10.1016/j.lungcan.2014.12.015
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center