scholarly journals A Fusion Protein of the Estrogen Receptor (ER) and Nuclear Receptor Corepressor (NCoR) Strongly Inhibits Estrogen-Dependent Responses in Breast Cancer Cells

1999 ◽  
Vol 13 (12) ◽  
pp. 2122-2136 ◽  
Author(s):  
Pei-Yu Chien ◽  
Masafumi Ito ◽  
Youngkyu Park ◽  
Tetsuya Tagami ◽  
Barry D. Gehm ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Dna Binding ◽  
Fusion Protein ◽  
Cancer Cells ◽  
Nuclear Receptor ◽  
Fusion Proteins ◽  
Breast Cancer Cells ◽  
Dominant Negative ◽  
Dominant Negative Activity

Abstract Nuclear receptor corepressor (NCoR) mediates repression (silencing) of basal gene transcription by nuclear receptors for thyroid hormone and retinoic acid. The goal of this study was to create novel estrogen receptor (ER) mutants by fusing transferable repressor domains from the N-terminal region of NCoR to a functional ER fragment. Three chimeric NCoR-ER proteins were created and shown to lack transcriptional activity. These fusion proteins silenced basal transcription of the ERE2-tk-Luc reporter gene and inhibited the activity of cotransfected wild-type ER (wtER), indicating that they possess dominant negative activity. One of the fusion proteins (CDE-RD1), containing the ER DNA-binding and ligand-binding domains linked to the NCoR repressor domain (RD1), was selected for detailed examination. Its hormone affinity, intracellular localization, and level of expression in transfected cells were similar to wtER, and it bound to the estrogen response element (ERE) DNA in gel shift assays. Glutathione-S-transferase pull-down assays showed that CDE-RD1 retains the ability to bind to steroid receptor coactivator-1. Introduction of a DNA-binding domain mutation into the CDE-RD1 fusion protein eliminated silencing and dominant negative activity. Thus, the RD1 repressor domain prevents transcriptional activation despite the apparent ability of CDE-RD1 to bind DNA, ligand, and coactivators. Transcriptional silencing was incompletely reversed by trichostatin A, suggesting a histone deacetylase-independent mechanism for repression. CDE-RD1 inhibited ER-mediated transcription in T47D and MDA-MB-231 breast cancer cells and repressed the growth of T47D cells when delivered to the cells by a retroviral vector. These ER-NCoR fusion proteins provide a novel means for inhibiting ER-mediated cellular responses, and analogous strategies could be used to create dominant negative mutants of other transcription factors.

scholarly journals Adenovirus-directed Expression of Dominant Negative Estrogen Receptor Induces Apoptosis in Breast Cancer Cells and Regression of Tumors in Nude Mice

2001 ◽  
Vol 7 (11) ◽  
pp. 773-782 ◽  
Author(s):  
Eun Jig Lee ◽  
Monika Jakacka ◽  
W. Rachel Duan ◽  
Pei Yu Chien ◽  
Fred Martinson ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Cancer Cells ◽  
Nude Mice ◽  
Breast Cancer Cells ◽  
Dominant Negative

Characterization of stably transfected fusion protein GFP-estrogen receptor-? in MCF-7 human breast cancer cells

2002 ◽  
Vol 86 (2) ◽  
pp. 365-375 ◽  
Author(s):  
Helen Zhao ◽  
Laura L. Hart ◽  
Ulrike Keller ◽  
Laurel T. Holth ◽  
James R. Davie
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Fusion Protein ◽  
Cancer Cells ◽  
Human Breast Cancer ◽  
Breast Cancer Cells ◽  
Human Breast Cancer Cells ◽  
Human Breast ◽  
Mcf 7

scholarly journals Functional role of TRPC6 and STIM2 in cytosolic and endoplasmic reticulum Ca2+ content in resting estrogen receptor-positive breast cancer cells

2020 ◽  
Vol 477 (17) ◽  
pp. 3183-3197
Author(s):  
Jose Sanchez-Collado ◽  
Jose J. Lopez ◽  
Lucia Gonzalez-Gutierrez ◽  
Carlos Cantonero ◽  
Isaac Jardin ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Endoplasmic Reticulum ◽  
Estrogen Receptor ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Dominant Negative ◽  
Cellular Functions ◽  
Mcf7 Cells ◽  
Membrane Expression ◽  
Estrogen Receptor Positive

TRPC6 forms non-selective cation channels activated by a variety of stimuli that are involved in a wide number of cellular functions. In estrogen receptor-positive (ER+) breast cancer cells, the store-operated Ca2+ entry has been reported to be dependent on STIM1, STIM2 and Orai3, with TRPC6 playing a key role in the activation of store-operated Ca2+ entry as well as in proliferation, migration and viability of breast cancer cells. We have used a combination of biotinylation, Ca2+ imaging as well as protein knockdown and overexpression of a dominant-negative TRPC6 mutant (TRPC6dn) to show that TRPC6 and STIM2 are required for the maintenance of cytosolic and endoplasmic reticulum Ca2+ content under resting conditions in ER+ breast cancer MCF7 cells. These cells exhibit a greater plasma membrane expression of TRPC6 under resting conditions than non-tumoral breast epithelial cells. Attenuation of STIM2, TRPC6 and Orai3, alone or in combination, results in impairment of resting cytosolic and endoplasmic reticulum Ca2+ homeostasis. Similar results were observed when cells were transfected with expression plasmid for TRPC6dn. TRPC6 co-immunoprecipitates with STIM2 in resting MCF7 cells, a process that is impaired by rises in cytosolic Ca2+ concentration. Impairment of TRPC6 function leads to abnormal Ca2+ homeostasis and endoplasmic reticulum stress, thus, suggesting that TRPC6 might be a potential target for the development of anti-tumoral therapies.

scholarly journals NR2F2 Orphan Nuclear Receptor is Involved in Estrogen Receptor Alpha-Mediated Transcriptional Regulation in Luminal A Breast Cancer Cells

2020 ◽  
Vol 21 (6) ◽  
pp. 1910
Author(s):  
Edina Erdős ◽  
Bálint László Bálint
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Cancer Cells ◽  
Nuclear Receptor ◽  
Breast Cancer Cells ◽  
Estrogen Receptor Alpha ◽  
Thyroid Hormone Receptor ◽  
Cardiovascular Development ◽  
Luminal A ◽  
Receptor Alpha

Nuclear Receptor Subfamily 2 Group F Member 2 (NR2F2) is a member of the steroid/thyroid hormone receptor superfamily with a crucial role in organogenesis, angiogenesis, cardiovascular development and tumorigenesis. However, there is limited knowledge about the cistrome and transcriptome of NR2F2 in breast cancer. In this study, we mapped the regulatory mechanism by NR2F2 using functional genomic methods. To investigate the clinical significance of NR2F2 in breast cancer, The Cancer Genome Atlas (TCGA) data were used. These results show that a high NR2F2 is associated with better survival of a specific subset of patients, namely those with luminal A breast cancer. Therefore, genome-wide NR2F2 and estrogen receptor alpha (ERα) binding sites were mapped in luminal A breast cancer cells using chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-Seq), revealing that most NR2F2 overlap with ERα that are co-occupied by forkhead box A1 (FOXA1) and GATA binding protein 3 (GATA3) in active enhancer regions. NR2F2 overlaps with highly frequent ERα chromatin interactions, which are essential for the formation of ERα-bound super-enhancers. In the process of the transcriptome profiling of NR2F2-depleted breast cancer cells such differentially expressed genes have been identified that are involved in endocrine therapy resistance and are also ERα target genes. Overall, these findings demonstrate that the NR2F2 nuclear receptor has a key role in ERα-mediated transcription and it can offer a potential therapeutic target in patients with luminal A breast cancer.

scholarly journals Metastasis-Associated Protein 1 Interacts with NRIF3, an Estrogen-Inducible Nuclear Receptor Coregulator

2004 ◽  
Vol 24 (15) ◽  
pp. 6581-6591 ◽  
Author(s):  
Amjad H. Talukder ◽  
Anupama Gururaj ◽  
Sandip K. Mishra ◽  
Ratna K. Vadlamudi ◽  
Rakesh Kumar
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Cancer Cells ◽  
Nuclear Receptor ◽  
Breast Cancer Cells ◽  
Target Gene ◽  
Gene Promoter ◽  
Terminal Region ◽  
Stimulation Of ◽  
Inducible Gene

ABSTRACT The transcriptional activity of estrogen receptor alpha (ER-α) is modified by regulatory action and interactions of coactivators and corepressors. Recent studies have shown that the metastasis-associated protein 1 (MTA1) represses estrogen receptor element (ERE)-driven transcription in breast cancer cells. With a yeast two-hybrid screen to clone MTA1-interacting proteins, we identified a known nuclear receptor coregulator (NRIF3) as an MTA1-binding protein. NRIF3 interacted with MTA1 both in vitro and in vivo. NRIF3 bound to the C-terminal region of MTA1, while MTA1 bound to the N-terminal region of NRIF3, containing one nuclear receptor interaction LXXLL motif. We showed that NRIF3 is an ER coactivator, hyperstimulated ER transactivation functions, and associated with the endogenous ER and its target gene promoter. MTA1 repressed NRIF3-mediated stimulation of ERE-driven transcription and interfered with NRIF3's association with the ER target gene chromatin. In addition, NRIF3 deregulation enhanced the responsiveness of breast cancer cells to estrogen-induced stimulation of growth and anchorage independence. Furthermore, we found that NRIF3 is an estrogen-inducible gene and activated ER associated with the ER response element in the NRIF3 gene promoter. These findings suggest that NRIF3, an MTA1-interacting protein, is an estrogen-inducible gene and that regulatory interactions between MTA1 and NRIF3 might be important in modulating the sensitivity of breast cancer cells to estrogen.

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