Loading…

Wnt Signaling Promotes Breast Cancer by Blocking ITCH-Mediated Degradation of YAP/TAZ Transcriptional Coactivator WBP2

Cross-talk between the Hippo and Wnt pathways has been implicated recently in breast cancer development, but key intersections have yet to be fully defined. Here we report that WBP2, a transcription coactivator that binds the Hippo pathway transcription factor YAP/TAZ, contributes to Wnt signaling a...

Full description

Saved in:
Bibliographic Details
Published in:Cancer research (Chicago, Ill.) Ill.), 2016-11, Vol.76 (21), p.6278-6289
Main Authors: Lim, Shen Kiat, Lu, Ssu Yi, Kang, Shin-Ae, Tan, Hock Jin, Li, Zilin, Adrian Wee, Zhen Ning, Guan, Jye Swei, Reddy Chichili, Vishnu Priyanka, Sivaraman, J, Putti, Thomas, Thike, Aye Aye, Tan, Puay Hoon, Sudol, Marius, Virshup, David M, Chan, Siew Wee, Hong, Wanjin, Lim, Yoon Pin
Format: Article
Language:English
Subjects:
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Cross-talk between the Hippo and Wnt pathways has been implicated recently in breast cancer development, but key intersections have yet to be fully defined. Here we report that WBP2, a transcription coactivator that binds the Hippo pathway transcription factor YAP/TAZ, contributes to Wnt signaling and breast cancer pathogenesis. Clinically, overexpression of WBP2 in breast cancer specimens correlated with malignant progression and poor patient survival. In breast cancer cells, nuclear entry and interaction of WBP2 with β-catenin was stimulated by Wnt3A, thereby activating TCF-mediated transcription and driving malignant invasive character. Mechanistic investigations showed WBP2 levels were controlled by the E3 ligase ITCH, which bound and target WBP2 for ubiquitin-dependent proteasomal degradation. Accordingly, ITCH silencing could elevate WBP2 levels. Wnt signaling upregulated WBP2 by disrupting ITCH-WBP2 interactions via EGFR-mediated tyrosine phosphorylation of WBP2 and TAZ/YAP competitive binding. Conversely, ITCH-mediated downregulation of WBP2 inhibited TCF/β-catenin transcription, in vitro transformation, and in vivo tumorigenesis. We identified somatic mutations in ITCH, which impaired its ability to degrade WBP2 and to block its function in cancer, even while retaining binding capacity to WBP2. Thus, the Wnt pathway appeared to engage WBP2 primarily by affecting its protein stability. Our findings show how WBP2/ITCH signaling functions to link the intricate Wnt and Hippo signaling networks in breast cancer. Cancer Res; 76(21); 6278-89. ©2016 AACR.
ISSN:0008-5472
1538-7445
DOI:10.1158/0008-5472.CAN-15-3537