| Title |
BRCA1-mimetic compound NSC35446.HCl inhibits IKKB expression by reducing estrogen receptor-α occupancy in the IKKB promoter and inhibits NF-κB activity in antiestrogen-resistant human breast cancer cells
|
|---|---|
| Published in |
Breast Cancer Research and Treatment, August 2017
|
| DOI | 10.1007/s10549-017-4442-y |
| Pubmed ID | |
| Authors |
Shyam Nathan, Yongxian Ma, York A. Tomita, Eliseu De Oliveira, Milton L. Brown, Eliot M. Rosen |
| Abstract |
We previously identified small molecules that fit into a BRCA1-binding pocket within estrogen receptor-alpha (ERα), mimic the ability of BRCA1 to inhibit ERα activity ("BRCA1-mimetics"), and overcome antiestrogen resistance. One such compound, the hydrochloride salt of NSC35446 ("NSC35446.HCl"), also inhibited the growth of antiestrogen-resistant LCC9 tumor xenografts. The purpose of this study was to investigate the down-stream effects of NSC35446.HCl and its mechanism of action. Here, we studied antiestrogen-resistant (LCC9, T47DCO, MCF-7/RR, LY2), ERα-negative (MDA-MB-231, HCC1806, MDA-MB-468), and antiestrogen-sensitive (MCF-7) cell lines. Techniques utilized include RNA-seq, qRT-PCR, cell growth analysis, cell-cycle analysis, Western blotting, luciferase reporter assays, TUNEL assays, in silico analysis of the IKKB gene, and ChIP assays. SC35446.HCl inhibited proliferation and induced apoptosis in antiestrogen-resistant LCC9, T47DCO, MCF-7/RR, and LY2 cells but not in ERα-negative breast cancer cell lines. IKKB (IKKβ, IKBKB), an upstream activator of NF-κB, was identified as a BRCA1-mimetic-regulated gene based on an RNA-seq analysis. NSC35446.HCl inhibited IKKB, IKKA, and IKKG/NEMO mRNA and protein expression in LCC9 cells. NSC35446.HCl also inhibited NF-κB activity and expression of NF-κB target genes. In silico analysis of the IKKB promoter identified nine estrogen response element (ERE) half-sites and one ERE-like full-site. ChIP assays revealed that ERα was recruited to the ERE-like full-site and five of the nine half-sites and that ERα recruitment was inhibited by NSC35446.HCl in LCC9 and T47DCO cells. These studies identify functional EREs in the IKKB promoter and identify IKKB as an ERα and NSC35446.HCl-regulated gene, and they suggest that NF-κB and IKKB, which were previously linked to antiestrogen resistance, are targets for NSC35446.HCl in reversing antiestrogen resistance. |
X Demographics
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Geographical breakdown
| Country | Count | As % |
|---|---|---|
| Unknown | 1 | 100% |
Demographic breakdown
| Type | Count | As % |
|---|---|---|
| Science communicators (journalists, bloggers, editors) | 1 | 100% |
Mendeley readers
The data shown below were compiled from readership statistics for 9 Mendeley readers of this research output. Click here to see the associated Mendeley record.
Geographical breakdown
| Country | Count | As % |
|---|---|---|
| Unknown | 9 | 100% |
Demographic breakdown
| Readers by professional status | Count | As % |
|---|---|---|
| Student > Bachelor | 3 | 33% |
| Student > Postgraduate | 2 | 22% |
| Student > Ph. D. Student | 1 | 11% |
| Unknown | 3 | 33% |
| Readers by discipline | Count | As % |
|---|---|---|
| Biochemistry, Genetics and Molecular Biology | 2 | 22% |
| Chemistry | 2 | 22% |
| Neuroscience | 1 | 11% |
| Engineering | 1 | 11% |
| Unknown | 3 | 33% |
Attention Score in Context
This research output has an Altmetric Attention Score of 1. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 22 August 2017.
All research outputs
#20,444,703
of 22,999,744 outputs
Outputs from Breast Cancer Research and Treatment
#4,125
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Outputs of similar age
#277,274
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Outputs of similar age from Breast Cancer Research and Treatment
#70
of 80 outputs
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