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Updated: Oct 25, 2025
16:24
Profiling of Estrogen-regulated MicroRNAs in Breast Cancer Cells
Published on: February 21, 2014
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RAC1 plays an essential role in estrogen receptor alpha function in breast cancer cells
Jun Sun1,2, Gabriel Gaidosh3, Ye Xu1,2
1Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, USA.
Oncogene
|August 10, 2021
Summary
RAC1 protein activity is crucial for estrogen receptor (ER) stability and gene transcription in ER-positive breast cancer. Inhibiting RAC1 may offer a new therapeutic strategy for this cancer type.
Area of Science:
- Oncology
- Molecular Biology
- Cell Biology
Background:
- Rho family GTPase protein, RAC1, is dysregulated in various cancers.
- RAC1 is present in both ER-positive and ER-negative breast cancer cells, with ER-positive BC showing higher sensitivity to RAC1 inhibition.
Purpose of the Study:
- To investigate the role of RAC1 in ER-positive breast cancer.
- To determine if RAC1 inhibition can be a therapeutic strategy for ER-positive BC.
Main Methods:
- Utilized siRNA and EHT 1864 (a small molecule Rac inhibitor) to reduce RAC1 activity.
- Examined RAC1 interaction with ER within the ER complex and its localization to chromatin.
- Assessed RAC1's role in RNA Pol II function and ER-regulated gene transcription.
Main Results:
- Reduced RAC1 activity led to rapid ER protein degradation.
- RAC1 interacts with ER and localizes to ER chromatin binding sites.
- RAC1 activity is essential for RNA Pol II function at ER target gene promoters and enhancers.
- EHT 1864 blocked ER-regulated gene transcription in a dose-dependent manner.
Conclusions:
- RAC1 acts as an essential ER cofactor, crucial for ER protein stability and transcriptional activity.
- Targeting RAC1 through inhibition presents a potential therapeutic approach for ER-positive breast cancer.
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