David Dominguez-Sola

E-cadherin protein plays a key role in the establishment and maintenance of adherent junctions. Recent evidence implicates the transcription factor Snail in the blockage of E-cadherin expression in fibroblasts and some epithelial tumor cells through direct binding to three E-boxes in the E-cadherin promoter. Transfection of Snail into epithelial cells leads to a more fibroblastic phenotype. Cells expressing Snail presented a scattered flattened phenotype with low intercellular contacts. Other epithelial markers like Cytokeratin 18 or MUC1 were also repressed. The effects of Snail on MUC1 transcription were mediated by two E-boxes present in the proximal promoter. Snail also induced expression of the mesenchymal markers fibronectin and LEF1 and the transcription repressor ZEB1. ZEB1 and Snail had a similar pattern of expression in epithelial cell lines, and both were induced by overexpression of ILK1, a kinase that causes the loss of E-cadherin and the acquisition of a fibroblastic phenotype. Snail overexpression in several cell lines raised ZEB1 RNA levels and increased the activity of ZEB1 promoter. ZEB1 could also repress E-cadherin and MUC1 promoters but less strongly than Snail. However, since ZEB1 expression persisted after Snail was down-regulated, ZEB1 may regulate epithelial genes in several tumor cell lines. E-cadherin protein plays a key role in the establishment and maintenance of adherent junctions. Recent evidence implicates the transcription factor Snail in the blockage of E-cadherin expression in fibroblasts and some epithelial tumor cells through direct binding to three E-boxes in the E-cadherin promoter. Transfection of Snail into epithelial cells leads to a more fibroblastic phenotype. Cells expressing Snail presented a scattered flattened phenotype with low intercellular contacts. Other epithelial markers like Cytokeratin 18 or MUC1 were also repressed. The effects of Snail on MUC1 transcription were mediated by two E-boxes present in the proximal promoter. Snail also induced expression of the mesenchymal markers fibronectin and LEF1 and the transcription repressor ZEB1. ZEB1 and Snail had a similar pattern of expression in epithelial cell lines, and both were induced by overexpression of ILK1, a kinase that causes the loss of E-cadherin and the acquisition of a fibroblastic phenotype. Snail overexpression in several cell lines raised ZEB1 RNA levels and increased the activity of ZEB1 promoter. ZEB1 could also repress E-cadherin and MUC1 promoters but less strongly than Snail. However, since ZEB1 expression persisted after Snail was down-regulated, ZEB1 may regulate epithelial genes in several tumor cell lines. epithelial to mesenchymal transition integrin-linked kinase lymphoid enhancer factor reverse transcription human Snail gene, Sna, mouse Snail gene Madin-Darby canine kidney hemagglutinin Rous sarcoma virus Homo sapiens firefly luciferase tetracycline The poor prognosis in epithelial neoplasia is associated with the acquisition of motile or invasive properties by the cancerous cells. This morphological transformation is often referred to as epithelial mesenchymal transition (EMT).1 EMT was first described in development when it is closely regulated and associated with processes like gastrulation or neuroepithelium formation. Molecular events during EMT include alterations in cell-cell adhesion, cell-substrate interaction, extracellular matrix degradation, and cytoskeleton organization. During EMT, epithelial markers are down-regulated, among them E-cadherin, a protein essential for the establishment of cell-cell adhesion (for review, see Refs. 1Hay E.D. Acta Anat. (Basel). 1995; 154: 8-20Crossref PubMed Scopus (1244) Google Scholar, 2Boyer B. Vallés A.M. Edme N. Biochem. Pharmacol. 2000; 60: 1091-1099Crossref PubMed Scopus (383) Google Scholar, 3Savagner P. Bioessays. 2001; 23: 912-923Crossref PubMed Scopus (607) Google Scholar). In cancerous cells there is a high correlation between invasion and metastasis and the loss of E-cadherin (4Vleminckx K. Vakaet Jr., L. Mareel M. Fiers W. van Roy F. Cell. 1991; 66: 107-119Abstract Full Text PDF PubMed Scopus (1510) Google Scholar, 5Perl A.K. Wilgenbus P. Dahl U. Semb H. Christofori G.A. Nature. 1998; 392: 190-193Crossref PubMed Scopus (1200) Google Scholar), whereas during gastrulation E-cadherin is down-regulated in progenitor cells in the primitive streak (6Oda H. Tsukita S. Takeichi M. Dev. Biol. 1998; 203: 435-450Crossref PubMed Scopus (203) Google Scholar). Control of E-cadherin transcription is the main mechanism responsible for the down-regulation of this protein (7Hennig G. Lowrick O. Birchmeier W. Behrens J. J. Biol. Chem. 1996; 271: 595-602Abstract Full Text Full Text PDF PubMed Scopus (124) Google Scholar, 8Ji X. Woodard A.S. Rimm D.L. Fearon E.R. Cell Growth Differ. 1997; 8: 773-778PubMed Google Scholar). A transcriptional factor called Snail (SNA in humans and Sna in mice) represses E-cadherin transcription in vitro and in vivo by binding to a 5′-CACCTG-3′ sequence of the E-cadherin promoter (9Batlle E. Sancho E. Francı́ C. Domı́nguez D. Monfar M. Baulida J. Garcı́a de Herreros A. Nat. Cell Biol. 2000; 2: 84-89Crossref PubMed Scopus (2172) Google Scholar). Transfection of Snail in epithelial cells decreases E-cadherin levels and induces changes resembling EMT (9Batlle E. Sancho E. Francı́ C. Domı́nguez D. Monfar M. Baulida J. Garcı́a de Herreros A. Nat. Cell Biol. 2000; 2: 84-89Crossref PubMed Scopus (2172) Google Scholar, 10Cano A. Pérez-Moreno M.A. Rodrigo I. Locascio A. Blanco M.J. del Barrio M.G. Portillo F. Nieto M.A. Nat. Cell Biol. 2000; 2: 76-83Crossref PubMed Scopus (2931) Google Scholar). In addition, Snail is believed to contribute to the EMT in several experimental models. For instance, during Drosophilagastrulation, Snail function is required for the repression in the mesoderm of genes that are otherwise expressed in the adjacent neuroectodermal regions of the blastoderm (11Casal J. Leptin M. Proc. Natl. Acad. Sci. U. S. A. 1996; 93: 10327-10332Crossref PubMed Scopus (37) Google Scholar). Further evidence was obtained from Sna −/− mouse embryos, which show an incomplete EMT: a new mesoderm is formed, but the resulting cells maintain epithelial markers like E-cadherin (12Carver E.A. Jiang R. Lan Y. Oram K.F. Gridley T. Mol. Cell. Biol. 2001; 21: 8184-8188Crossref PubMed Scopus (512) Google Scholar). Other mutants that show defects in EMT and cell migration during gastrulation are fibroblast growth factor receptor 1 (−/−) animals; these defects have been attributed to a severe reduction of Snail expression in the primitive streak accompanied by ectopic expression of E-cadherin (13Ciruna B. Rossant J. Dev. Cell. 2001; 1: 37-49Abstract Full Text Full Text PDF PubMed Scopus (513) Google Scholar). Several conditions also induce EMT in epithelial cell lines (3Savagner P. Bioessays. 2001; 23: 912-923Crossref PubMed Scopus (607) Google Scholar). Snail is involved in a number of processes: for instance, activation of integrin-linked kinase (ILK), which mediates extracellular matrix signals (14Hannigan G.E. Leung-Hagesteijn C. Fitz-Gibbon L. Coppolino M.G. Radeva G. Filmus J. Bell J.C. Dedhar S. Nature. 1996; 379: 91-96Crossref PubMed Scopus (967) Google Scholar, 15Dedhar S. Curr. Opin. Cell Biol. 2000; 12: 250-256Crossref PubMed Scopus (195) Google Scholar), increases Snail promoter activity and down-regulates E-cadherin (16Tan C. Costello P. Sanghera J. Domı́nguez D. Baulida J. Garcı́a de Herreros A. Dedhar S. Oncogene. 2001; 20: 133-140Crossref PubMed Scopus (232) Google Scholar). Finally, increased Snail expression has been described in some carcinogenic cell lines with invasive capacity (10Cano A. Pérez-Moreno M.A. Rodrigo I. Locascio A. Blanco M.J. del Barrio M.G. Portillo F. Nieto M.A. Nat. Cell Biol. 2000; 2: 76-83Crossref PubMed Scopus (2931) Google Scholar, 17Poser I. Dominguez D. Garcia de Herreros A. Varnai A. Buettner R. Bosserhoff A.K. J. Biol. Chem. 2001; 276: 24661-24666Abstract Full Text Full Text PDF PubMed Scopus (235) Google Scholar, 18Cheng C.W., Wu, P.E., Yu, J.C. Huang C.S. Yue C.T., Wu, C.W. Shen C.Y. Oncogene. 2001; 20: 3814-3823Crossref PubMed Scopus (196) Google Scholar, 19Jiao W. Miyazaki K. Kitajima Y. Br. J. Cancer. 2002; 7: 98-101Crossref Scopus (132) Google Scholar). In this study we have examined with greater detail the changes induced by the ectopic expression of Sna in epithelial cells. In addition to showing the ultrastructural modifications observed in cells expressing Sna, we have also characterized several genes that show an altered expression. One of these genes isZEB1, 2In this study we use the name ZEB1 to refer to the gene that has also been called ZEB,AREB6 (in humans), BZP (in hamster), or δEF1 (in chicken) (GenBankTM accession numberU12170) and ZEB2 for the gene also known as SIP1(GenBankTM accession numberAB011141). a transcriptional repressor also capable of blocking the expression of E-cadherin. The data obtained together with data previously reported clearly show that Snail induces a complete EMT. The generation of Madin-Darby canine kidney (MDCK) cells and HT-29 M6 cells transfected with Sna-HA has been described (9Batlle E. Sancho E. Francı́ C. Domı́nguez D. Monfar M. Baulida J. Garcı́a de Herreros A. Nat. Cell Biol. 2000; 2: 84-89Crossref PubMed Scopus (2172) Google Scholar). HT-29 M6 SNA1 and SNA2 correspond to two clones obtained by transfection with a tet-regulated expression vector (tet-off) containing hemagglutinin-tagged mouse Snail cDNA (Sna). MDCK SNA1 and SNA3 are two MDCK Sna-expressing clones obtained by transfection of MDCK cells with pIRES-neo Sna-HA (9Batlle E. Sancho E. Francı́ C. Domı́nguez D. Monfar M. Baulida J. Garcı́a de Herreros A. Nat. Cell Biol. 2000; 2: 84-89Crossref PubMed Scopus (2172) Google Scholar). IEC-18 rat cells transfected with wild-type or negative forms of ILK or with an antisense construction of this kinase were obtained as described previously (14Hannigan G.E. Leung-Hagesteijn C. Fitz-Gibbon L. Coppolino M.G. Radeva G. Filmus J. Bell J.C. Dedhar S. Nature. 1996; 379: 91-96Crossref PubMed Scopus (967) Google Scholar). Other human (HT-29, SW-480, SW-620, ZR-75, T47D, MCF-7, MiaPaca, and RWP-1) or mouse (EpH4 and NIH-3T3) cell lines were obtained from our institute Cell Bank. All cells were grown in Dulbecco's modified Eagle's medium (Invitrogen) containing 10% fetal calf serum (Biological Industries) and the standard supplements. Murine ZEB1cDNA was provided by T. Genetta (Children's Hospital of Philadelphia, Philadelphia, PA) and cloned into pcDNA3HisC expression vector (Promega) at the EcoRI site.ZEB2-CS2MT expression vector was kindly provided by A. Postigo (Washington University, St. Louis, MO). Sna-HA was cloned into RSV 5 expression vector inserting the 0.9-kbHindIII-NotI fragment from pcDNA3Sna-HA at the XhoI site of RSV 5. Blunt ends were generated using the Klenow fragment from DNA polymerase (New England Biolabs). Commercial anti-ZEB1 was obtained from Santa Cruz Biotechnology (goat anti-ZEB1 C-20, sc-10570) and monoclonal anti-E-cadherin from Transduction Laboratories (c20820). Antiserum against recombinant mouse Snail was raised in New Zealand rabbits by standard protocols and purified by affinity chromatography using recombinant murine Snail. Postconfluent cells were fixed in 2% glutaraldehyde for 30 min and embedded in EPON (Tousimis Research Corp., Rockville, MD). Semithin and were obtained and using standard For were observed using a were a standard of RNA by were in a with and to a by The RNA was to the using a and with using MUC1 DNA was from of purified MUC1 cDNA by reverse transcription to polymerase from HT-29 M6 RNA using the and to a sequence in the number were by using from of RNA was using with The of were Sna, Cytokeratin E-cadherin, and The and antisense with The number of and at at at at 30 at E-cadherin, at 30 at at Cytokeratin at and at The correspond to in the the accession E-cadherin, Cytokeratin and The promoter sequence containing to from the transcription site was cloned by from HT-29 DNA using high polymerase and and to sequence containing at the was cloned into the and of a (9Batlle E. Sancho E. Francı́ C. Domı́nguez D. Monfar M. Baulida J. Garcı́a de Herreros A. Nat. Cell Biol. 2000; 2: 84-89Crossref PubMed Scopus (2172) Google of vector (Promega) Snail binding site of the was A in the two was obtained using the The sequence was are in ZEB1 promoter to from the was from the using and to number containing at the The fragment was cloned into the of at the All were by of E-cadherin promoter activity was by or Sna in (Invitrogen) with or promoters in the cell lines. a luciferase or from to transfection luciferase and luciferase were using the (Promega) after transfection to the activity was by In the of DNA transfected was with or were and were at three ZEB1 or MUC1 promoter activity in Sna clones was by of or promoter and and luciferase activity as Cells were on to to fixed with with in and with or was as cells were observed in a protein expression was by using of obtained by the cells in The of several of the HT-29 M6 and MDCK cell clones in this is in The main of these cells is the to and a more scattered In HT-29 M6 clones transfected with the the epithelial phenotype was by addition of the tetracycline which expression of Snail 1 and E. Sancho E. Francı́ C. Domı́nguez D. Monfar M. Baulida J. Garcı́a de Herreros A. Nat. Cell Biol. 2000; 2: 84-89Crossref PubMed Scopus (2172) Google Scholar). obtained from HT-29 M6 clones that Snail overexpression the of the of HT-29 M6 cells and the from to HT-29 M6 SNA1 like the Sna-expressing a phenotype with cells on the of cell were observed in these in to HT-29 M6 clones and were clones also of and of epithelial cells like and cell properties were also altered in the Sna with the transition from an epithelial to a mesenchymal phenotype. In addition to a in intercellular adhesion and data Sna-expressing clones to and on several as or in these two are observed in fibroblasts with to epithelial cells like HT-29 HT-29 M6 Sna clones with were from also these changes in phenotype were accompanied by alterations in the expression of a we RNA levels of several epithelial than E-cadherin, to in clones of HT-29 M6 cells of MUC1 and Cytokeratin which in promoters in the and ZEB1 were in Sna levels of have been reported in MDCK cells transfected with Snail (10Cano A. Pérez-Moreno M.A. Rodrigo I. Locascio A. Blanco M.J. del Barrio M.G. Portillo F. Nieto M.A. Nat. Cell Biol. 2000; 2: 76-83Crossref PubMed Scopus (2931) Google the in the of this protein responsible for the of and of Sna ZEB1 and LEF1 are two transcription to mesenchymal LEF1 is the cell factor in mesenchymal cells and is expressed in some processes as T. T. J. Nat. 2001; PubMed Google Scholar). the ZEB1 is a transcriptional factor described to involved in E-cadherin repression Oncogene. 2000; PubMed Scopus Google Scholar). the changes in gene expression that this epithelial to mesenchymal transition we to in greater detail the of two that is and that is MUC1 is a of several epithelial the promoter sequence a of the Snail DNA binding sequence at from the transcription A. N. D. J. J. Biol. Chem. Full Text PDF PubMed Google Scholar). like E-cadherin, this gene is a direct of Snail. RNA levels were in Sna-expressing HT-29 M6 clones than in we the of MUC1 RNA was a of a repression of the activity of the promoter. to sequence containing to with to the transcription A. N. D. J. J. Biol. Chem. Full Text PDF PubMed Google Scholar), was cloned and into the of the luciferase This promoter has been described to in epithelial cell lines expressing MUC1 A. N. D. J. J. Biol. Chem. Full Text PDF PubMed Google Scholar). MUC1 transcriptional activity was in the Sna clones than in or cells The repression of promoter was when Snail was transfected in HT-29 M6 cells or epithelial cells. In Snail the activity of the promoter in a by to This repression was observed with the Sna which E-cadherin promoter activity (9Batlle E. Sancho E. Francı́ C. Domı́nguez D. Monfar M. Baulida J. Garcı́a de Herreros A. Nat. Cell Biol. 2000; 2: 84-89Crossref PubMed Scopus (2172) Google Scholar). of the in the promoter of to the in MUC1 promoter activity A similar has been reported to binding of Snail to E-cadherin promoter E-boxes and repression of this promoter (9Batlle E. Sancho E. Francı́ C. Domı́nguez D. Monfar M. Baulida J. Garcı́a de Herreros A. Nat. Cell Biol. 2000; 2: 84-89Crossref PubMed Scopus (2172) Google Scholar). the of a Snail binding sequence is required to MUC1 that Snail represses the expression of at epithelial in addition to E-cadherin. The of ZEB1 expression was also ZEB1 is also a transcriptional repressor like of the activity of the E-cadherin promoter. the expression of these three genes and was in a of epithelial cell lines expressing of E-cadherin. of the low of transcription factor present in a RNA we to Sna and ZEB1. in cell lines in which Snail and ZEB1 were was E-cadherin down-regulated In a cell lines, like we expression of both E-cadherin and Snail but ZEB1. also the expression of Snail is induced in conditions in which cells EMT. as a IEC-18 epithelial cells that EMT when transfected with G.E. Leung-Hagesteijn C. Fitz-Gibbon L. Coppolino M.G. Radeva G. Filmus J. Bell J.C. Dedhar S. Nature. 1996; 379: 91-96Crossref PubMed Scopus (967) Google Scholar). an ILK was IEC-18 cells a phenotype that with a down-regulation of E-cadherin. Snail was in these overexpression of ILK induced an in the RNA to this that the ILK also induced ZEB1 RNA ZEB1 to induced with Snail and the acquisition of the phenotype in IEC-18 cells. The of Snail in ZEB1 activation was by our data with Sna in our Sna-expressing HT-29 M6 clones ZEB1 RNA levels were A more study was in these clones of the of the expression of this gene by the tetracycline ZEB1 RNA transcription was after Snail RNA expression was on by from the medium of Sna was after which required Sna expression is to the ZEB1 RNA the when Sna expression was by ZEB1 RNA as Sna, but The of ZEB1 RNA in the of Snail that ZEB1 could the repression of epithelial genes by Snail. This to of these HT-29 M6 clones since MDCK clones also increased levels RNA The mechanism by which Snail induces ZEB1 was Snail induces the transcription we cloned a DNA fragment of first and promoter activity in MDCK and Sna-expressing cells. Sna-expressing MDCK clones activity than of this promoter that Snail increases ZEB1 RNA at in by the activation of the transcription of this this we the activity in transfection of Snail. In cells Snail also increased the transcriptional activity of the ZEB1 this was observed when the activity was in cells transfected than The ZEB1 has also been described to as an E-cadherin repressor J. G. P. K. van L. E. Mareel M. D. van Roy F. Mol. Cell. 2001; 7: Full Text Full Text PDF PubMed Scopus Google Scholar). However, it to Snail activation in of our and expression with that of Snail in the epithelial cell lines it was in the cell lines 5 the first to the role of ZEB1 as a repressor in the Snail we that ZEB1 protein was also in A of this protein was in the in HT-29 M6 and MDCK clones also the repression activity of ZEB1 on E-cadherin promoter transcription in several epithelial cell lines using a proximal E-cadherin promoter to of a luciferase gene This promoter sequence three 5′-CACCTG-3′ Snail and ZEB1 ZEB1 the promoter activity in a with a of in the cell lines which HT-29 and MDCK The of repression obtained with ZEB1 and Snail were both were expressed the ZEB1 required a to the repression in the cell lines This on the E-cadherin promoter was accompanied by changes in the expression of this protein ZEB1 also the to repress E-cadherin less than Snail. the ZEB2 the promoter with a of in cells effects were observed in of repression of Sna and ZEB1 on E-cadherin of the activity of this promoter by both are repression activity of ZEB1 and Snail. Cells were with of promoter and or 5 of and the of Sna, in In luciferase activity was after transfection and into the obtained with show the of three to in also ZEB1 Snail using the promoter show in a similar to ZEB1 the promoter activity to the obtained with E-cadherin ZEB1 was at less than Snail as a repressor of the In epithelial cells changes in phenotype and to mesenchymal cells. This EMT is observed in several of development and in cell invasion and of E-cadherin gene is down-regulated during these processes (4Vleminckx K. Vakaet Jr., L. Mareel M. Fiers W. van Roy F. Cell. 1991; 66: 107-119Abstract Full Text PDF PubMed Scopus (1510) Google Scholar, 5Perl A.K. Wilgenbus P. Dahl U. Semb H. Christofori G.A. Nature. 1998; 392: 190-193Crossref PubMed Scopus (1200) Google Scholar). However, EMT a of a of epithelial or markers than E-cadherin and an of E.D. Acta Anat. (Basel). 1995; 154: 8-20Crossref PubMed Scopus (1244) Google Scholar). (9Batlle E. Sancho E. Francı́ C. Domı́nguez D. Monfar M. Baulida J. Garcı́a de Herreros A. Nat. Cell Biol. 2000; 2: 84-89Crossref PubMed Scopus (2172) Google and (10Cano A. Pérez-Moreno M.A. Rodrigo I. Locascio A. Blanco M.J. del Barrio M.G. Portillo F. Nieto M.A. Nat. Cell Biol. 2000; 2: 76-83Crossref PubMed Scopus (2931) Google have reported that the transcriptional repressor Snail E-cadherin expression by binding to E-boxes in but the mechanism by which levels of are regulated in EMT is in have that two transcription Snail and regulate the expression of mesenchymal and epithelial some mesenchymal genes also regulated by transcriptional genes like and (11Casal J. Leptin M. Proc. Natl. Acad. Sci. U. S. A. 1996; 93: 10327-10332Crossref PubMed Scopus (37) Google Scholar). (for review, see M.A. Nat. Mol. Cell Biol. 2002; PubMed Scopus Google as as data obtained after transfection to epithelial cells that Sna induces a complete EMT when transfected to epithelial cells. of this capacity of Sna to study the of repression of epithelial genes or activation of mesenchymal genes than E-cadherin, like MUC1 and Cytokeratin also E-boxes on show that RNA levels of these genes are after Snail expression and and that repression of MUC1 E-boxes MUC1 and E-cadherin to regulated by a mechanism that Snail. However, with affinity for this sequence may also in the down-regulation of MUC1 and E-cadherin the genes by Snail we a transcriptional also capable of binding the E-boxes as Snail. ZEB1 and ZEB2 are which is of Snail in Snail is required for the expression in the mesoderm in Snail expression is Dev. 1991; PubMed Scopus Google Scholar). obtained from and clones clearly show that Snail increases ZEB1 RNA and protein levels during EMT. have also through that ZEB1 is at in to an of the transcriptional activity of the ZEB1 promoter the ZEB1 promoter we that Snail promoter since the required to the of the is than the required to repress E-cadherin or MUC1 promoters and and was after of expression of Snail in a like represses E-cadherin and when transfected into epithelial cells. tumor cell lines with severe reduction of E-cadherin expressed both Snail and ZEB1 and Snail and ZEB1 repression were In addition to the of ZEB1 RNA in when Snail expression was expression required more than to to levels This that in of a expression of ZEB1 repression of epithelial In with this in after Snail is down-regulated M. Dev. 1991; PubMed Scopus Google Scholar, S. M. Dev. 1996; PubMed Scopus Google Scholar). However, whereas are to gastrulation (12Carver E.A. Jiang R. Lan Y. Oram K.F. Gridley T. Mol. Cell. Biol. 2001; 21: 8184-8188Crossref PubMed Scopus (512) Google Scholar), ZEB1 is for this to show severe in cell in the and several defects T. H. H. Y. 1998; PubMed Google Scholar). but is for the E-cadherin down-regulation required for a The of tumor cell lines with epithelial or mesenchymal as as IEC-18 cells expressing ILK a high between ZEB1 and E-cadherin expression. This is than that presented by E-cadherin and Snail since we several cell lines expressing these two However, data from our that the of Snail with the activity of this factor since in several cell lines, in that present expression of E-cadherin, Snail protein is from the B. J. M. A. C. J. and A. Garcı́a de in together with obtained with that Snail is the key E-cadherin transcription and EMT ZEB1 expression in of epithelial cell lines. However, in some ZEB1 to Snail activation as a of in the promoter or the activation of some of transcriptional and E-cadherin expression. All cell lines expression of of Snail and E-cadherin This expression was modified during EMT of IEC-18 cells or after of Snail. strongly a for the expression of the ZEB1 is induced by Snail and is to fibroblastic whereas ZEB2 is expressed in the cell lines, of epithelial or mesenchymal ZEB2 induces repression of E-cadherin promoter in some J. G. P. K. van L. E. Mareel M. D. van Roy F. Mol. Cell. 2001; 7: Full Text Full Text PDF PubMed Scopus Google this factor activity than ZEB1 or Snail. The in the repression of E-cadherin between ZEB1 and ZEB2 may to the of the Proc. Natl. Acad. Sci. U. S. A. 2000; PubMed Scopus Google Scholar). In our that the of ZEB2 repress the activity of epithelial promoters in tumor cells. However, to the of ZEB2 with Snail to repress epithelial promoters to Postigo and Genetta for kindly The of and M. is also J. for with