期刊
BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH
卷 1823, 期 6, 页码 1110-1118出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/j.bbamcr.2012.04.005
关键词
Claudin-2; Lung; Matrix metalloproteinase; Epidermal growth factor; c-Fos
资金
- JSPS KAKENHI [23590263]
- Pharmacological Research Foundation, Tokyo
- SRI
- Grants-in-Aid for Scientific Research [23590263, 22590068] Funding Source: KAKEN
In human adenocarcinoma. claudin-2 expression is higher than that in normal lung tissue, but the regulatory mechanism of its expression has not been clarified. In human adenocarcinoma A549 cells, claudin-2 level time-dependently increased under the control conditions. In contrast, claudin-1 expression remained constant for 24 h. The concentration of epidermal growth factor (EGF) in medium time-dependently increased, which was inhibited by matrix metalloproteinase (MMP) inhibitor II, an inhibitor of MMP-1, 3, 7, and 9. MMP inhibitor II decreased claudin-2 and phospholylated ERK1/2 (p-ERK1/2) levels, which were recovered by EGF. Both claudin-2 and p-ERK1/2 levels were decreased by EGF neutralizing antibody, EGF receptor (EGFR) siRNA, AG1478, an inhibitor of EGER. U0126, an inhibitor of MEK, and the exogenous expression of dominant negative-MEK These results suggest that EGF is secreted from A549 cells by MMP and increases claudin-2 expression mediated via the activation of an EGFR/MEK/ERK pathway. The inhibition of the signaling pathway decreased phosphorylated c-Fos and nuclear c-Fos levels. The introduction of c-Fos siRNA decreased claudin-2 level without affecting claudin-1. The promoter activity of human claudin-2 was decreased by AG1478 and U0126. Furthermore, the activity was decreased by the deletion or mutation of the AP-1 binding site of claudin-2 promoter. Chromatin immunoprecipitation and avidin-biotin conjugated DNA assays showed that c-Fos binds to the AP-1 binding site. We suggest that a secreted EGF up-regulates the transcriptional activity of claudin-2 mediated by the activation of an EGFR/MEK/ERK/c-Fos pathway in A549 cells. (C) 2012 Elsevier B.V. All rights reserved.
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