Carcinogenesis Advance Access originally published online on August 12, 2004
Carcinogenesis 2004 25(12):2385-2395; doi:10.1093/carcin/bgh248
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Carcinogenesis vol.25 no.12 © Oxford University Press 2004; all rights reserved.
ARTICLE |
Oncogenic Raf-1 regulates epithelial to mesenchymal transition via distinct signal transduction pathways in an immortalized mouse hepatic cell line
Department of Pathology, Sapporo Medical University School of Medicine, S1 W17, Sapporo 060-8556, Japan
1 To whom correspondence should be addressed. Tel: +81 11 611 2111; Fax: +81 11 613 5665; Email: ktakashi{at}sapmed.ac.jp
The epithelial to mesenchymal transition (EMT) is considered to be an important event during malignant tumor progression and metastasis. Although Raf/MEK/ERK signaling causes EMT, the mechanisms, including the signaling pathways, are as yet unclear. In the present study we have examined the effects of signal transduction pathways on oncogenic Raf-1-induced EMT, using an immortalized mouse hepatic cell line. Oncogenic Raf-1-induced EMT is characterized by down-regulation of adherens and tight junctions and the reorganization of actin. An active Raf-1 gene was introduced into a mouse hepatic cell line which was then treated with the MAP kinase inhibitor PD98059, the p38 MAP kinase inhibitor SB203580, the PI3 kinase inhibitor LY294002 or the c-Src tyrosine kinase inhibitor PP2. The expression and localization of the adherens and tight junction proteins E-cadherin, occludin, ZO-1, claudin-1 and claudin-2 were determined by western blotting, RT–PCR and immunocytochemistry. The barrier function of tight junctions was assessed by measurements of transepithelial electric resistance (TER) and permeability in terms of fluxes of [14C]mannitol and [14C]inulin. In Raf-1-transfected cells expression of occludin and claudin-2 was markedly down-regulated at the protein and mRNA levels and the TER value was decreased, while the permeability was increased. The distribution of ZO-1, pancadherin and F-actin was changed from linear to zipper-like structures at cell borders. In Raf-1-transfected cells treated with PD98059 and SB203580, but not LY294002, expression and localization of claudin-2, but not occludin, recovered, together with barrier function, measured as the TER value. The distributions of ZO-1, pancadherin and F-actin also recovered on treatment with PD98059 and SB203580, but not LY294002. Expression and localization of occludin recovered slightly on treatment with PP2. Thus, oncogenic Raf-1 regulates EMT via distinct MAP kinase, p38 MAP kinase and c-Src tyrosine kinase signal pathways in the mouse hepatic cell line.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  R. Yanai, J.-A. Ko, N. Nomi, N. Morishige, T.-i. Chikama, A. Hattori, K. Hozumi, M. Nomizu, and T. Nishida Upregulation of ZO-1 in Cultured Human Corneal Epithelial Cells by a Peptide (PHSRN) Corresponding to the Second Cell-Binding Site of Fibronectin Invest. Ophthalmol. Vis. Sci., June 1, 2009; 50(6): 2757 - 2764. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 V. Pollack, R. Sarkozi, Z. Banki, E. Feifel, S. Wehn, G. Gstraunthaler, H. Stoiber, G. Mayer, R. Montesano, F. Strutz, et al. Oncostatin M-induced effects on EMT in human proximal tubular cells: differential role of ERK signaling Am J Physiol Renal Physiol, November 1, 2007; 293(5): F1714 - F1726. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Tokunaga, T. Kojima, M. Osanai, M. Murata, H. Chiba, H. Tobioka, and N. Sawada A Novel Monoclonal Antibody Against the Second Extracellular Loop of Occludin Disrupts Epithelial Cell Polarity J. Histochem. Cytochem., July 1, 2007; 55(7): 735 - 744. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. Guillemot and S. Citi Cingulin Regulates Claudin-2 Expression and Cell Proliferation through the Small GTPase RhoA Mol. Biol. Cell, August 1, 2006; 17(8): 3569 - 3577. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Shimada, M. Nakamura, S. Matsuyoshi, E. Ishida, and N. Konishi Specific positive and negative effects of FLIP on cell survival in human prostate cancer Carcinogenesis, July 1, 2006; 27(7): 1349 - 1357. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. B. N. Lee, E. Huang, and H. J. Ward Tight junction biology and kidney dysfunction Am J Physiol Renal Physiol, January 1, 2006; 290(1): F20 - F34. [Abstract] [Full Text] [PDF]
|
|