title: Involvement of the MEK/ERK pathway in EGF-induced E-cadherin down-regulation.
abstract: E-cadherin is a major component of the epithelial adherens junction. However, the regulatory mechanism of E-cadherin expression is still poorly understood. In this study, we found that EGF decreased E-cadherin expression at both mRNA and protein levels in colorectal carcinoma LoVo cells. Since E-cadherin down-regulation is a well-known hallmark of the EMT (Epithelial-Mesenchymal Transition), we investigated whether EGF induced E-cadherin down-regulation during the EMT. EGF was unable to affect the expression of mesenchymal markers (such as N-cadherin, vimentin or fibronectin) or EMT-regulating transcription factors (such as SNAIL, SLUG, ZEB1, ZEB2 or TWIST), suggesting that EGF induced E-cadherin down-regulation via an EMT-independent mechanism. On the other hand, the MEK inhibitor U0126 was found to suppress EGF-induced E-cadherin down-regulation at the transcriptional level, suggesting that the MEK/ERK pathway is involved in EGF-induced E-cadherin down-regulation. Moreover, we also found that EGF disrupted cell-cell contact, stimulated cells to form an elongated shape with filamentous protrusions, and induced cell migration in LoVo cells. These effects were suppressed by U0126. Therefore, EGF is suggested to induce E-cadherin down-regulation at the transcriptional level through the MEK/ERK pathway, which might result in, at least in part, the induction of cellular morphological changes and cell migration in LoVo cells.
authors.affiliation: Department of Biosciences and Informatics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama City 223-8522, Japan. Electronic address: tashiro@bio.keio.ac.jp.
authors.forename: Etsu
authors.initials: E
authors.lastname: Tashiro
authors.affiliation: Department of Biosciences and Informatics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama City 223-8522, Japan.
authors.forename: Shizuka
authors.initials: S
authors.lastname: Henmi
authors.affiliation: Department of Biosciences and Informatics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama City 223-8522, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Odake
authors.affiliation: Department of Biosciences and Informatics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama City 223-8522, Japan.
authors.forename: Seitaro
authors.initials: S
authors.lastname: Ino
authors.affiliation: Department of Biosciences and Informatics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama City 223-8522, Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Imoto
mesh_terms: D015703:Antigens, CD; D015820:Cadherins / Q000378:metabolism*; D045744:Cell Line, Tumor; D002465:Cell Movement; D015179:Colorectal Neoplasms / Q000378:metabolism* / Q000473:pathology; D015536:Down-Regulation; D004815:Epidermal Growth Factor / Q000008:administration & dosage*; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D020935:MAP Kinase Signaling System
chemical_list: D015703:Antigens, CD; C513384:CDH1 protein, human; D015820:Cadherins; D004815:Epidermal Growth Factor
keywords: E-cadherin; EGF; EMT; ERK; JNK