Tyrosine phosphorylation of transcriptional coactivator WW-domain binding protein 2 regulates estrogen receptor α function in breast cancer via the Wnt pathway.
FASEB J
; 25(9): 3004-18, 2011 Sep.
Article
em En
| MEDLINE
| ID: mdl-21642474
ABSTRACT
WW-binding protein 2 (WBP2) has been demonstrated in different studies to be a tyrosine kinase substrate, to activate estrogen receptor α (ERα)/progesterone receptor (PR) transcription, and to play a role in breast cancer. However, the role of WBP2 tyrosine phosphorylation in regulating ERα function and breast cancer biology is unknown. Here, we established WBP2 as a tyrosine phosphorylation target of estrogen signaling via EGFR crosstalk. Using dominant-negative, constitutively active mutants, RNAi, and pharmacological studies, we demonstrated that phosphorylation of WBP2 at Tyr192 and Tyr231 could be regulated by c-Src and c-Yes kinases. We further showed that abrogating WBP2 phosphorylation impaired >60% of ERα reporter activity, putatively by blocking nuclear entry of WBP2 and its interaction with ERα. Compared to vector control, overexpression of WBP2 and its phospho-mimic mutant in MCF7 cells resulted in larger tumors in mice, induced loss of cell-cell adhesion, and enhanced cell proliferation, anchorage-independent growth, migration, and invasion in both estrogen-dependent and -independent manners, events of which could be substantially abolished by overexpression of the phosphorylation-defective mutant. Hormone independence of cells expressing WBP2 phospho-mimic mutant was associated with heightened ERα and Wnt reporter activities. Wnt/ß-catenin inhibitor FH535 blocked phospho-WBP2-mediated cancer cell growth more pronouncedly than tamoxifen and fulvestrant, in part by reducing the expression of ERα. Wnt pathway is likely to be a critical component in WBP2-mediated breast cancer biology.
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Base de dados:
MEDLINE
Assunto principal:
Tirosina
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Proteínas de Transporte
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Neoplasias Mamárias Animais
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Receptor alfa de Estrogênio
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Proteínas Wnt
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Neoplasias Experimentais
Limite:
Animals
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Female
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Humans
Idioma:
En
Ano de publicação:
2011
Tipo de documento:
Article