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A feedback loop between BEX2 and ErbB2 mediated by c-Jun signaling in breast cancer
Ali Naderi1, Ji Liu, Glenn D Francis
1Diamantina Institute, The University of Queensland, Princess Alexandra Hospital, Brisbane, Queensland, Australia. a.naderi@uq.edu.au
International Journal of Cancer
|March 9, 2011
Summary
Brain expressed X-linked gene 2 (BEX2) protein is overexpressed in about half of breast cancers. BEX2 forms a positive feedback loop with ErbB2, regulated by c-Jun signaling, impacting breast cancer progression.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Brain expressed X-linked gene 2 (BEX2) is implicated in breast cancer, with prior studies showing it protects against apoptosis and cell cycle arrest.
- BEX2 is a target gene of c-Jun and influences c-Jun phosphorylation in breast cancer cells.
Purpose of the Study:
- To investigate BEX2 protein expression in breast tumors.
- To elucidate the relationship between BEX2, ErbB2, and c-Jun signaling in breast cancer.
Main Methods:
- Tissue microarray analysis of 225 breast tissue samples.
- In vitro experiments using breast cancer cell models (MCF-7).
- Assessment of protein expression (BEX2, ErbB2, phosphorylated c-Jun) and gene promoter binding.
Main Results:
- BEX2 protein was overexpressed in approximately 50% of malignant breast tumors versus 7% of benign samples.
- BEX2-positive tumors correlated with ErbB2 and phosphorylated c-Jun overexpression.
- A functional feedback loop was identified where ErbB2 induces c-Jun and BEX2, and BEX2 enhances ErbB2 expression via c-Jun.
Conclusions:
- BEX2 protein is frequently overexpressed in breast cancer.
- A positive feedback loop involving ErbB2, c-Jun, and BEX2 signaling contributes to breast cancer pathogenesis.
- Targeting this BEX2-mediated feedback loop may offer therapeutic strategies for breast cancer.
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