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MUC1 oncoprotein stabilizes and activates estrogen receptor alpha
Xiaolong Wei1, Hai Xu, Donald Kufe
1Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA.
Molecular Cell
|January 24, 2006
Summary
The MUC1 protein stabilizes estrogen receptor alpha (ERalpha) in breast cancer cells, enhancing its function and promoting tumor growth. This interaction is crucial for ERalpha-mediated transcription and cell survival.
Area of Science:
- Oncology
- Molecular Biology
- Endocrinology
Background:
- Aberrant MUC1 protein overexpression is common in human breast carcinomas.
- Estrogen receptor alpha (ERalpha) plays a critical role in breast cancer development and progression.
Purpose of the Study:
- To investigate the interaction between MUC1 and ERalpha in breast cancer.
- To elucidate the functional consequences of MUC1-ERalpha association on ERalpha activity and breast cancer cell behavior.
Main Methods:
- Co-immunoprecipitation assays to detect MUC1-ERalpha interaction.
- Western blotting to assess ERalpha ubiquitination and degradation.
- Chromatin immunoprecipitation (ChIP) assays to evaluate ERalpha and MUC1 binding to target promoters.
- Reporter gene assays to measure ERalpha-mediated transcriptional activity.
Main Results:
- MUC1 C-terminal subunit directly binds to the ERalpha DNA binding domain.
- MUC1 association stabilizes ERalpha by inhibiting its ubiquitination and degradation.
- MUC1 enhances ERalpha recruitment to estrogen-responsive promoters and increases coactivator (SRC-1, GRIP1) recruitment.
- MUC1 stimulates ERalpha-mediated transcription, promoting 17beta-estradiol (E2)-induced breast cancer cell growth and survival.
Conclusions:
- MUC1 stabilizes ERalpha, thereby enhancing its transcriptional activity.
- MUC1 acts as a critical oncoprotein by modulating ERalpha function in breast cancer.
- Targeting the MUC1-ERalpha interaction may offer a therapeutic strategy for ERalpha-positive breast cancers.