Abstract
Two important protein-protein interactions establish E-cadherin (Cdh1) in the adhesion complex; homophilic binding via the extra-cellular (EC1) domain and cytoplasmic tail binding to β-catenin. Here, we evaluate whether E-cadherin binding can inhibit β-catenin when there is loss of Adenomatous polyposis coli (APC) from the β-catenin destruction complex. Combined conditional loss of Cdh1 and Apc were generated in the intestine, intestinal adenoma and adenoma organoids. Combined intestinal disruption (Cdh1fl/flApcfl/flVil-CreERT2) resulted in lethality, breakdown of the intestinal barrier, increased Wnt target gene expression and increased nuclear β-catenin localization, suggesting that E-cadherin inhibits β-catenin. Combination with an intestinal stem cell Cre (Lgr5CreERT2) resulted in ApcΔ/Δ recombination and adenoma, but intact Cdh1fl/fl alleles. Cultured ApcΔ/ΔCdh1fl/fl adenoma cells infected with adenovirus-Cre induced Cdh1fl/fl recombination (Cdh1Δ/Δ), disruption of organoid morphology, nuclear β-catenin localization, and cells with an epithelial-mesenchymal phenotype. Complementation with adenovirus expressing wild-type Cdh1 (Cdh1-WT) rescued adhesion and β-catenin membrane localization, yet an EC1 specific double mutant defective in homophilic adhesion (Cdh1-MutW2A, S78W) did not. These data suggest that E-cadherin inhibits β-catenin in the context of disruption of the APC-destruction complex, and that this function is also EC1 domain dependent. Both binding functions of E-cadherin may be required for its tumour suppressor activity.
Original language | English |
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Pages (from-to) | 69883-69902 |
Number of pages | 20 |
Journal | OncoTarget |
Volume | 7 |
Issue number | 43 |
DOIs | |
Publication status | Published - 25 Oct 2016 |
Keywords
- Adenoma/etiology
- Adenomatous Polyposis Coli Protein/physiology
- Animals
- Antigens, CD
- Cadherins/chemistry
- Cell Nucleus/metabolism
- Embryonic Development
- Epithelial-Mesenchymal Transition
- Humans
- Intestinal Neoplasms/etiology
- MCF-7 Cells
- Mice
- Organoids
- Protein Domains
- Recombination, Genetic
- Tamoxifen/pharmacology
- beta Catenin/metabolism