RRC ID 43811
Author Ikari A, Sato T, Watanabe R, Yamazaki Y, Sugatani J.
Title Increase in claudin-2 expression by an EGFR/MEK/ERK/c-Fos pathway in lung adenocarcinoma A549 cells.
Journal Biochim. Biophys. Acta
Abstract 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 24h. 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 phosphorylated 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 EGFR, 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.
Volume 1823(6)
Pages 1110-8
Published 2012-6
DOI 10.1016/j.bbamcr.2012.04.005
PII S0167-4889(12)00096-1
PMID 22546605
MeSH Adenocarcinoma / enzymology* Adenocarcinoma / genetics* Adenocarcinoma of Lung Binding Sites Butadienes / pharmacology Cell Line, Tumor Claudins / genetics* Claudins / metabolism Epidermal Growth Factor / metabolism ErbB Receptors / antagonists & inhibitors ErbB Receptors / metabolism* Female Gene Expression Regulation, Neoplastic* / drug effects Humans Lung Neoplasms / enzymology* Lung Neoplasms / genetics* MAP Kinase Signaling System* / drug effects Male Nitriles / pharmacology Promoter Regions, Genetic / genetics Protease Inhibitors / pharmacology Protein Binding / drug effects Proto-Oncogene Proteins c-fos / metabolism* Quinazolines RNA, Messenger / genetics RNA, Messenger / metabolism RNA, Small Interfering / metabolism Transcription Factor AP-1 / metabolism Tyrphostins
IF 3.79
Times Cited 21
Human and Animal Cells