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The androgen receptor interacts with GATA3 to transcriptionally regulate a luminal epithelial cell phenotype in breast cancer.

Published version
Peer-reviewed

Repository DOI


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Authors

Hosseinzadeh, Leila 
Kikhtyak, Zoya 
Laven-Law, Geraldine 
Pederson, Stephen M 
Puiu, Caroline G 

Abstract

BACKGROUND: The androgen receptor (AR) is a tumor suppressor in estrogen receptor (ER) positive breast cancer, a role sustained in some ER negative breast cancers. Key factors dictating AR genomic activity in a breast context are largely unknown. Herein, we employ an unbiased chromatin immunoprecipitation-based proteomic technique to identify endogenous AR interacting co-regulatory proteins in ER positive and negative models of breast cancer to gain new insight into mechanisms of AR signaling in this disease. RESULTS: The DNA-binding factor GATA3 is identified and validated as a novel AR interacting protein in breast cancer cells irrespective of ER status. AR activation by the natural ligand 5α-dihydrotestosterone (DHT) increases nuclear AR-GATA3 interactions, resulting in AR-dependent enrichment of GATA3 chromatin binding at a sub-set of genomic loci. Silencing GATA3 reduces but does not prevent AR DNA binding and transactivation of genes associated with AR/GATA3 co-occupied loci, indicating a co-regulatory role for GATA3 in AR signaling. DHT-induced AR/GATA3 binding coincides with upregulation of luminal differentiation genes, including EHF and KDM4B, established master regulators of a breast epithelial cell lineage. These findings are validated in a patient-derived xenograft model of breast cancer. Interaction between AR and GATA3 is also associated with AR-mediated growth inhibition in ER positive and ER negative breast cancer. CONCLUSIONS: AR and GATA3 interact to transcriptionally regulate luminal epithelial cell differentiation in breast cancer regardless of ER status. This interaction facilitates the tumor suppressor function of AR and mechanistically explains why AR expression is associated with less proliferative, more differentiated breast tumors and better overall survival in breast cancer.

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Keywords

Androgen receptor, Breast, GATA3, Luminal lineage, Female, Humans, Breast Neoplasms, Cell Line, Tumor, Epithelial Cells, GATA3 Transcription Factor, Jumonji Domain-Containing Histone Demethylases, Phenotype, Proteomics, Receptors, Androgen

Journal Title

Genome Biol

Conference Name

Journal ISSN

1474-7596
1474-760X

Volume Title

25

Publisher

Springer Science and Business Media LLC
Sponsorship
National Health and Medical Research Council (1084416, 1084416, 1084416, 1084416, 1130077, 1130077, 1130077, 1130077)
National Breast Cancer Foundation (IIRS-22-003, IIRS-19-009)