title: SNAIL1 combines competitive displacement of ASCL2 and epigenetic mechanisms to rapidly silence the EPHB3 tumor suppressor in colorectal cancer.
abstract: EPHB3 is a critical cellular guidance factor in the intestinal epithelium and an important tumor suppressor in colorectal cancer (CRC) whose expression is frequently lost at the adenoma-carcinoma transition when tumor cells become invasive. The molecular mechanisms underlying EPHB3 silencing are incompletely understood. Here we show that EPHB3 expression is anti-correlated with inducers of epithelial-mesenchymal transition (EMT) in primary tumors and CRC cells. In vitro, SNAIL1 and SNAIL2, but not ZEB1, repress EPHB3 reporter constructs and compete with the stem cell factor ASCL2 for binding to an E-box motif. At the endogenous EPHB3 locus, SNAIL1 triggers the displacement of ASCL2, p300 and the Wnt pathway effector TCF7L2 and engages corepressor complexes containing HDACs and the histone demethylase LSD1 to collapse active chromatin structure, resulting in rapid downregulation of EPHB3. Beyond its impact on EPHB3, SNAIL1 deregulates markers of intestinal identity and stemness and in vitro forces CRC cells to undergo EMT with altered morphology, increased motility and invasiveness. In xenotransplants, SNAIL1 expression abrogated tumor cell palisading and led to focal loss of tumor encapsulation and the appearance of areas with tumor cells displaying a migratory phenotype. These changes were accompanied by loss of EPHB3 and CDH1 expression. Intriguingly, SNAIL1-induced phenotypic changes of CRC cells are significantly impaired by sustained EPHB3 expression both in vitro and in vivo. Altogether, our results identify EPHB3 as a novel target of SNAIL1 and suggest that disabling EPHB3 signaling is an important aspect to eliminate a roadblock at the onset of EMT processes.
authors.affiliation: Institute of Molecular Medicine and Cell Research, Albert-Ludwigs-University Freiburg, Stefan-Meier-Str. 17, 79104 Freiburg, Germany; Faculty of Biology, Albert-Ludwigs-University Freiburg, Schänzlestr. 1, 79104 Freiburg, Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Rönsch
authors.affiliation: Institute of Molecular Medicine and Cell Research, Albert-Ludwigs-University Freiburg, Stefan-Meier-Str. 17, 79104 Freiburg, Germany; Faculty of Biology, Albert-Ludwigs-University Freiburg, Schänzlestr. 1, 79104 Freiburg, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Jägle
authors.affiliation: Institute of Molecular Medicine and Cell Research, Albert-Ludwigs-University Freiburg, Stefan-Meier-Str. 17, 79104 Freiburg, Germany.
authors.forename: Katja
authors.initials: K
authors.lastname: Rose
authors.affiliation: Department of Pathology, University Medical Center, Breisacher Str. 115a, 79106 Freiburg, Germany; Center for Chronic Immunodeficiency, University Medical Center, Breisacher Str. 117, 79106 Freiburg, Germany.
authors.forename: Maximilian
authors.initials: M
authors.lastname: Seidl
authors.affiliation: Department of Hematology and Oncology, University Medical Center, Hugstetter Str. 55, 79106 Freiburg, Germany.
authors.forename: Francis
authors.initials: F
authors.lastname: Baumgartner
authors.affiliation: Institute of Molecular Medicine and Cell Research, Albert-Ludwigs-University Freiburg, Stefan-Meier-Str. 17, 79104 Freiburg, Germany.
authors.forename: Vivien
authors.initials: V
authors.lastname: Freihen
authors.affiliation: Freiburg Institute for Advanced Studies (FRIAS), Albert-Ludwigs-University Freiburg, Albertstraße 19, 79104 Freiburg, Germany.
authors.forename: Afsheen
authors.initials: A
authors.lastname: Yousaf
authors.affiliation: Department of Urology/Women's Hospital and Center for Clinical Research, University Medical Center, Breisacher Str. 66, 79106 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University Freiburg, Schänzlestr. 18, 79104 Freiburg, Germany; German Consortium for Translational Cancer Research (DKTK) and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.
authors.forename: Eric
authors.initials: E
authors.lastname: Metzger
authors.affiliation: Department of Pathology, University Medical Center, Breisacher Str. 115a, 79106 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University Freiburg, Schänzlestr. 18, 79104 Freiburg, Germany; German Consortium for Translational Cancer Research (DKTK) and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.
authors.forename: Silke
authors.initials: S
authors.lastname: Lassmann
authors.affiliation: Department of Urology/Women's Hospital and Center for Clinical Research, University Medical Center, Breisacher Str. 66, 79106 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University Freiburg, Schänzlestr. 18, 79104 Freiburg, Germany; German Consortium for Translational Cancer Research (DKTK) and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.
authors.forename: Roland
authors.initials: R
authors.lastname: Schüle
authors.affiliation: Department of Hematology and Oncology, University Medical Center, Hugstetter Str. 55, 79106 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University Freiburg, Schänzlestr. 18, 79104 Freiburg, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Zeiser
authors.affiliation: Freiburg Institute for Advanced Studies (FRIAS), Albert-Ludwigs-University Freiburg, Albertstraße 19, 79104 Freiburg, Germany; The Roslin Institute, The University of Edinburgh, Easter Bush, Midlothian EH25 9RG, Scotland, UK.
authors.forename: Tom
authors.initials: T
authors.lastname: Michoel
authors.affiliation: Institute of Molecular Medicine and Cell Research, Albert-Ludwigs-University Freiburg, Stefan-Meier-Str. 17, 79104 Freiburg, Germany; Faculty of Biology, Albert-Ludwigs-University Freiburg, Schänzlestr. 1, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University Freiburg, Schänzlestr. 18, 79104 Freiburg, Germany. Electronic address: andreas.hecht@mol-med.uni-freiburg.de.
authors.forename: Andreas
authors.initials: A
authors.lastname: Hecht
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D018938:Caco-2 Cells; D002465:Cell Movement / Q000235:genetics; D015179:Colorectal Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D057809:HEK293 Cells; D064593:Heterografts; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D009368:Neoplasm Transplantation; D036223:Receptor, EphB3 / Q000096:biosynthesis* / Q000235:genetics; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000096:biosynthesis* / Q000235:genetics; D060449:Wnt Signaling Pathway / Q000235:genetics; D050880:p300-CBP Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D036223:Receptor, EphB3; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D050880:p300-CBP Transcription Factors; C065501:ASCL2 protein, human; C000604407:SNAI1 protein, human; C000604429:Snai1 protein, mouse
keywords: Colorectal cancer; EPHB3; Epigenetic regulation; Epithelial-mesenchymal transition; Snail1