title: Topoisomerase IIα mediates TCF-dependent epithelial-mesenchymal transition in colon cancer.
abstract: Aberrant T-cell factor (TCF) transcription is implicated in the majority of colorectal cancers (CRCs). TCF transcription induces epithelial-mesenchymal transition (EMT), promoting a tumor-initiating cell (TIC) phenotype characterized by increased proliferation, multidrug resistance (MDR), invasion and metastasis. The data presented herein characterize topoisomerase IIα (TopoIIα) as a required component of TCF transcription promoting EMT. Using chromatin immunoprecipitation (ChIP) and protein co-immunoprecipitation (co-IP) studies, we show that TopoIIα forms protein-protein interactions with β-catentin and TCF4 and interacts with Wnt response elements (WREs) and promoters of direct target genes of TCF transcription, including: MYC, vimentin, AXIN2 and LEF1. Moreover, both TopoIIα and TCF4 ChIP with the N-cadherin promoter, which is a new discovery indicating that TCF transcription may directly regulate N-cadherin expression. TopoIIα N-terminal ATP-competitive inhibitors, exemplified by the marine alkaloid neoamphimedine (neo), block TCF activity in vitro and in vivo. Neo effectively inhibits TopoIIα and TCF4 from binding WREs/promoter sites, whereas protein-protein interactions remain intact. Neo inhibition of TopoIIα-dependent TCF transcription also correlates with significant antitumor effects in vitro and in vivo, including the reversion of EMT, the loss of TIC-mediated clonogenic colony formation, and the loss of cell motility and invasion. Interestingly, non-ATP-competitive inhibitors of TopoIIα, etoposide and merbarone, were ineffective at preventing TopoIIα-dependent TCF transcription. Thus, we propose that TopoIIα participation in TCF transcription may convey a mechanism of MDR to conventional TopoIIα inhibitors. However, our results indicate that TopoIIα N-terminal ATP-binding sites remain conserved and available for drug targeting. This article defines a new strategy for targeted inhibition of TCF transcription that may lead to effective therapies for the treatment of CRC and potentially other Wnt-dependent cancers.
authors.affiliation: Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
authors.forename: Q
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
authors.forename: A D
authors.initials: AD
authors.lastname: Abraham
authors.affiliation: Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
authors.forename: L
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
authors.forename: A
authors.initials: A
authors.lastname: Babalmorad
authors.affiliation: Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
authors.forename: S
authors.initials: S
authors.lastname: Bagby
authors.affiliation: Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.|Division of Medical Oncology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
authors.forename: J J
authors.initials: JJ
authors.lastname: Arcaroli
authors.affiliation: Division of Medical Oncology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.|University of Colorado Cancer Center, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
authors.forename: R J
authors.initials: RJ
authors.lastname: Hansen
authors.affiliation: Colorado State University, Flint Animal Cancer Center, Fort Collins, CO, USA.
authors.forename: F A
authors.initials: FA
authors.lastname: Valeriote
authors.affiliation: Division of Medical Oncology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.|University of Colorado Cancer Center, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
authors.forename: D L
authors.initials: DL
authors.lastname: Gustafson
authors.affiliation: Division of Medical Oncology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.|Josephine Ford Cancer Center, Henry Ford Health Systems, Detroit, MI, USA.
authors.forename: J
authors.initials: J
authors.lastname: Schaack
authors.affiliation: Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.|Division of Medical Oncology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
authors.forename: W A
authors.initials: WA
authors.lastname: Messersmith
authors.affiliation: Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.|Division of Medical Oncology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
authors.forename: D V
authors.initials: DV
authors.lastname: LaBarbera
mesh_terms: D000951:Antigens, Neoplasm / Q000235:genetics*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000235:genetics; D047369:Chromatin Immunoprecipitation; D003110:Colonic Neoplasms / Q000235:genetics* / Q000473:pathology; D004250:DNA Topoisomerases, Type II / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D058750:Epithelial-Mesenchymal Transition / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D009361:Neoplasm Invasiveness / Q000235:genetics; D009362:Neoplasm Metastasis; D009363:Neoplasm Proteins / Q000096:biosynthesis; D060066:Protein Interaction Maps / Q000235:genetics; D058118:Transcription Factor 7-Like 2 Protein / Q000235:genetics*; D051176:beta Catenin / Q000235:genetics* / Q000378:metabolism
chemical_list: D000951:Antigens, Neoplasm; D004268:DNA-Binding Proteins; D009363:Neoplasm Proteins; C544894:TCF7L2 protein, human; D058118:Transcription Factor 7-Like 2 Protein; D051176:beta Catenin; D004250:DNA Topoisomerases, Type II