Anne-Hélène Monsoro-Burq, Perla El-Hage, Jacques Camonis, Ivan Bièche, Keltouma Driouch, Michèle Sabbah, Ambre Petitalot, Etienne Formstecher, Rosette Lidereau, François Lallemand, Frédérique Maczkowiak, Signalisation normale et pathologique de l'embryon aux thérapies innovante des cancers, Institut National de la Santé et de la Recherche Médicale ( INSERM ) -INSTITUT CURIE-Centre National de la Recherche Scientifique ( CNRS ), Unité de génétique et biologie des cancers ( U830 ), Université Paris Descartes - Paris 5 ( UPD5 ) -Institut Curie-Institut National de la Santé et de la Recherche Médicale ( INSERM ), Genetique Moleculaire des Cancers d'Origine Epitheliale, Institut National de la Santé et de la Recherche Médicale ( INSERM ) -INSTITUT CURIE, Hybrigenics [Paris], Hybrigenics, Genetics and Biology of Cancers INSERM U528 Institut Curie, Centre de Recherche Saint-Antoine ( CR Saint-Antoine ), Institut National de la Santé et de la Recherche Médicale ( INSERM ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ), Facultés des sciences pharmaceutiques et biologiques, Oncogénétique, INSTITUT CURIE-Hôpital René HUGUENIN (Saint-Cloud), Signalisation normale et pathologique de l'embryon aux thérapies innovantes des cancers, Institut Curie [Paris]-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Unité de génétique et biologie des cancers (U830), Université Paris Descartes - Paris 5 (UPD5)-Institut Curie [Paris]-Institut National de la Santé et de la Recherche Médicale (INSERM), Institut Curie [Paris]-Institut National de la Santé et de la Recherche Médicale (INSERM), Centre de Recherche Saint-Antoine (UMRS893), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Santé et de la Recherche Médicale (INSERM), Institut Curie [Paris]-Hôpital René HUGUENIN (Saint-Cloud), Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut Curie [Paris], Hôpital René HUGUENIN (Saint-Cloud)-Institut Curie [Paris], Institut Curie-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Université Paris Descartes - Paris 5 (UPD5)-Institut Curie-Institut National de la Santé et de la Recherche Médicale (INSERM), Institut Curie-Institut National de la Santé et de la Recherche Médicale (INSERM), Centre de Recherche Saint-Antoine (CR Saint-Antoine), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Pierre et Marie Curie - Paris 6 (UPMC), and Institut Curie-Hôpital René HUGUENIN (Saint-Cloud)
The WW domain containing oxidoreductase (WWOX) has recently been shown to inhibit of the Wnt/β-catenin pathway by preventing the nuclear import of disheveled 2 (DVL2) in human breast cancer cells. Here, it is revealed that WWOX also interacts with the BCL9-2, a cofactor of the Wnt/β-catenin pathway, to enhance the activity of the β-catenin–TCF/LEF (T-cell factor/lymphoid enhancer factors family) transcription factor complexes. By using both a luciferase assay in MCF-7 cells and a Xenopus secondary axis induction assay, it was demonstrated that WWOX inhibits the BCL9-2 function in Wnt/β-catenin signaling. WWOX does not affect the BCL9-2–β-catenin association and colocalizes with BCL9-2 and β-catenin in the nucleus of the MCF-7 cells. Moreover, WWOX inhibits the β-catenin–TCF1 interaction. Further examination found that HDAC3 associates with BCL9-2, enhances the inhibitory effect of WWOX on BCL9-2 transcriptional activity, and promotes the WWOX–BCL9-2 interaction, independent of its deacetylase activity. However, WWOX does not influence the HDAC3–BCL9-2 interaction. Altogether, these results strongly indicate that nuclear WWOX interacts with BCL9-2 associated with β-catenin only when BCL9-2 is in complex with HDAC3 and inhibits its transcriptional activity, in part, by inhibiting the β-catenin–TCF1 interaction. The promotion of the WWOX–BCL9-2 interaction by HDAC3, independent of its deacetylase activity, represents a new mechanism by which this HDAC inhibits transcription. Implications: The inhibition of the transcriptional activity of BCL9-2 by WWOX and HDAC3 constitutes a new molecular mechanism and provides new insight for a broad range of cancers. Mol Cancer Res; 13(5); 902–12. ©2015 AACR.