BRCA1 regulation of epidermal growth factor receptor (EGFR) expression in human breast cancer cells involves microRNA-146a and is critical for its tumor suppressor function
| Autor: | Karen L. Wendt, Laura A. Augustine, Emily C. Sibala, Shane R. Stecklein, Sumedha Gunewardena, Roy A. Jensen, Easwari Kumaraswamy, Dan Li |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
Transcriptional Activation
Cancer Research endocrine system diseases Triple Negative Breast Neoplasms Biology Article law.invention Breast cancer law Cell Line Tumor microRNA Genetics medicine Humans Epidermal growth factor receptor RNA Processing Post-Transcriptional Promoter Regions Genetic skin and connective tissue diseases Molecular Biology Cell Proliferation Gene knockdown BRCA1 Protein Tumor Suppressor Proteins medicine.disease ErbB Receptors MicroRNAs Cell Transformation Neoplastic Immunology Cancer cell Cancer research biology.protein Suppressor Cyclin-dependent kinase 8 Female Lymph Nodes |
| Zdroj: | Oncogene. 34:4333-4346 |
| ISSN: | 1476-5594 0950-9232 |
| Popis: | Breast cancer 1 (BRCA1)-associated breast cancers are mostly basal-like high-grade ductal carcinomas that frequently overexpress epidermal growth factor receptor (EGFR). Aberrant EGFR expression is correlated with disease progression, resistance to radiation and chemotherapy, and poor clinical prognosis. Although BRCA1 is involved in multiple cellular processes, its functional role in EGFR regulation remains enigmatic. Here, we report a previously unrecognized posttranscriptional mechanism by which BRCA1 regulates EGFR expression through the induction of miR-146a. We demonstrate that EGFR expression correlates negatively with BRCA1, whereas miR-146a levels increase with BRCA1. We show that BRCA1 binds to MIR146A promoter and activates transcription, which in turn attenuates EGFR expression. Knockdown of miR-146a in BRCA1-overexpressing cells negated this effect and suppressed its ability to inhibit proliferation and transformation. In archived triple-negative breast cancer samples, we show a strong positive correlation between BRCA1 and miR-146a expression. We also show that low expression of miR-146a strongly predicts positive lymph node status and is associated with distinctively poor overall survival of patients. Together, these observations provide an insight into a novel BRCA1miR-146aEGFR paradigm by which BRCA1 carries out an aspect of tumor suppressor function that is potentially amenable to therapeutic intervention. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|