Estrogen receptor coregulator binding modulators (ERXs) effectively target estrogen receptor positive human breast cancers
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE75664 | GEO | 2017/08/18
SECONDARY ACCESSION(S): PRJNA305002
REPOSITORIES: GEO
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Project description:The majority of human breast cancer is estrogen receptor alpha (ER) positive. While anti-estrogens/aromatase inhibitors are initially effective, resistance to these drugs commonly develops. Therapy-resistant tumors often retain ER signaling, via interaction with critical oncogenic coregulator proteins. To address these mechanisms of resistance, we have developed a novel ER coregulator binding modulator, ERX-11. ERX-11 interacts directly with ER and blocks the interaction between a subset of coregulators with both native and mutant forms of ER. ERX-11 effectively blocks ER-mediated oncogenic signaling and has potent anti-proliferative activity against therapy-sensitive and therapy-resistant human breast cancer cells. ERX-11 is orally bioavailable, with no overt signs of toxicity and potent activity in both murine xenograft and patient-derived breast tumor explant models. This first-in-class agent, with its novel mechanism of action of disrupting critical protein-protein interactions, overcomes the limitations of current therapies and may be clinically translatable for patients with therapy-sensitive and therapy-resistant breast cancers.
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2017-09-18 | GSE93807 | GEO
Project description:We examined the transcriptional changes modulated by knocking out ERβ and reintroduction of ERβ1 and ERβ5 isoforms by perfroming global transcriptome analysis. ERβ was knocked out in U87 cells using CRISPR/Cas9 system and reintroduced the ERβ1 and ERβ5 isoforms in knockout background. RNA was isolated from control U87, U87-ERβ-KO, U87-ERβ1 and U87-ERβ5 cells and utilized for RNA-seq analysis. Our results demonstrated that ERβ-KO, ERβ1 and ERβ5 modulated unique pathways including NF-κB singaling, Jak/STAT pathway and mTOR signaling.
2018-04-10 | GSE104296 | GEO
Project description:Biotinylated 4xERE-containing DNA immobilized on streptavidin beads used to pulldown proteins recruited by unliganded WT ER-alpha versus Y537S, D538G, or ESR1-YAP1 fusion proteins from HeLa S3 human cell nuclear extracts.
2017-02-08 | MSV000080536 | MassIVE
Project description:BACKGROUND:CDK4/6 inhibitors in combination with endocrine therapy (AE/AI/SERDs) are approved for the treatment of ER+ advanced breast cancer (BCa). However, not all patients benefit from CDK4/6 inhibitors therapy. We previously reported a novel therapeutic agent, ERX-11, that binds to the estrogen receptor (ER) and modulates ER-coregulator interactions. Here, we tested if the combination of ERX-11 with agents approved for ER+ BCa would be more potent. METHODS:We tested the effect of combination therapy using BCa cell line models, including those that have acquired resistance to tamoxifen, letrozole, or CDK4/6 inhibitors or have been engineered to express mutant forms of the ER. In vitro activity was tested using Cell Titer-Glo, MTT, and apoptosis assays. Mechanistic studies were conducted using western blot, reporter gene assays, RT-qPCR, and mass spectrometry approaches. Xenograft, patient-derived explants (PDEs), and xenograft-derived explants (XDE) were used for preclinical evaluation and toxicity. RESULTS:ERX-11 inhibited the proliferation of therapy-resistant BCa cells in a dose-dependent manner, including ribociclib resistance. The combination of ERX-11 and CDK4/6 inhibitor was synergistic in decreasing the proliferation of both endocrine therapy-sensitive and endocrine therapy-resistant BCa cells, in vitro, in xenograft models in vivo, xenograft-derived explants ex vivo, and in primary patient-derived explants ex vivo. Importantly, the combination caused xenograft tumor regression in vivo. Unbiased global mass spectrometry studies demonstrated profound decreases in proliferation markers with combination therapy and indicated global proteomic changes in E2F1, ER, and ER coregulators. Mechanistically, the combination of ERX-11 and CDK4/6 inhibitor decreased the interaction between ER and its coregulators, as evidenced by immunoprecipitation followed by mass spectrometry studies. Biochemical studies confirmed that the combination therapy significantly altered the expression of proteins involved in E2F1 and ER signaling, and this is primarily driven by a transcriptional shift, as noted in gene expression studies. CONCLUSIONS:Our results suggest that ERX-11 inhibited the proliferation of BCa cells resistant to both endocrine therapy and CDK4/6 inhibitors in a dose-dependent manner and that the combination of ERX-11 with a CDK4/6 inhibitor may represent a viable therapeutic approach.
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Project description:Although many features of active transcriptional enhancers have been defined by genomic assays, we lack a clear understanding of the order of events leading to enhancer formation and activation as well as the dynamics of coregulator interactions within the enhancer complex. Here, we used selective loss- or gain-of-function mutants of estrogen receptor α (ERα) to define two distinct phases of ligand-dependent enhancer formation. In the first phase (0-20 min), p300 is recruited to ERα by Mediator as well as p300's acetylhistone-binding bromodomain to promote initial enhancer formation, which is not competent for sustained activation. In the second phase (20-45 min), p300 is recruited to ERα by steroid receptor coregulators (SRCs) for enhancer maturation and maintenance. Successful transition between these two phases ("coregulator switching") is required for proper enhancer function. Failure to recruit p300 during either phase leads to abortive enhancer formation and a lack of target gene expression. Our results reveal an ordered and cooperative assembly of ERα enhancers requiring functional interplay among p300, Mediator, and SRCs, which has implications for hormone-dependent gene regulation in breast cancers. More broadly, our results demonstrate the unexpectedly dynamic nature of coregulator interactions within enhancer complexes, which are likely to be a defining feature of all enhancers.
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Project description:We examined the role of PELP1 in E2-ER-mediated transcription in the hippocampus under conditions of GCI by perfroming global transcriptome analysis. E2-treated FLOX and PELP1 FBKO mice were subjected to GCI followed by 24 h reperfusion and the isolated RNA was utilized for RNA-seq analysis. Our results demonstrated that PELP1 is needed for optimal activation of E2-regulated genes following GCI.
2015-12-07 | GSE72136 | GEO
Project description:Progesterone receptor (PgR) controls the menstrual cycle, pregnancy, embryonic development, and homeostasis, and it plays important roles in breast cancer development and progression. However, the requirement of coregulators for estrogen-induced expression of the PgR gene has not been fully explored. Here we used RNA interference to demonstrate dramatic differences in requirements of 10 different coregulators for estrogen-regulated expression of six different genes, including PgR and the well-studied TFF1 (or pS2) gene in MCF-7 breast cancer cells. Full estrogen-induced expression of TFF1 required all ten coregulators, but PgR induction required only four of the 10 coregulators. Chromatin immunoprecipitation studies demonstrated several mechanisms responsible for the differential coregulator requirements. Actin-binding coregulator Flightless-I, required for TFF1 expression and recruited to that gene by estrogen receptor-? (ER?), is not required for PgR expression and not recruited to that gene. Protein acetyltransferase tat-interactive protein 60 and ATP-dependent chromatin remodeler Brahma Related Gene 1 are recruited to both genes but are required only for TFF1 expression. Histone methyltransferase G9a is recruited to both genes and required for estrogen-induced expression of TFF1 but negatively regulates estrogen-induced expression of PgR. In contrast, histone methyltransferase myeloid/lymphoid or mixed-lineage leukemia 1 (MLL1), pioneer factor Forkhead box A1, and p160 coregulator steroid receptor coactivator-3 are required for expression of and are recruited to both genes. Depletion of MLL1 decreased ER? binding to the PgR and TFF1 genes. In contrast, depletion of G9a enhanced ER? binding to the PgR gene but had no effect on ER? binding to the TFF1 gene. These studies suggest that differential promoter architecture is responsible for promoter-specific mechanisms of gene regulation.
| S-EPMC3355545 | biostudies-literature
Project description:The transcriptional activity of estrogen receptor alpha (ER-alpha) 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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Project description:Selective estrogen receptor modulators (SERMs), such as tamoxifen (TAM), have been used extensively for the treatment and prevention of breast cancer and other pathologies associated with aberrant estrogen receptor (ER) signaling. These compounds exhibit cell-selective agonist/antagonist activities as a consequence of their ability to induce different conformational changes in ER, thereby enabling it to recruit functionally distinct transcriptional coregulators. However, the observation that SERMs can also regulate aspects of calcium signaling and apoptosis in an ER-independent manner in some systems suggests that some of the activity of drugs within this class may also arise as a consequence of their ability to interact with targets other than ER. In this study, we demonstrate that 4-hydroxy-TAM (4OHT), an active metabolite of TAM, directly binds to and modulates the transcriptional activity of the aryl hydrocarbon receptor (AHR). Of specific interest was the observation, that in the absence of ER, 4OHT can induce the expression of AHR target genes involved in estradiol metabolism, cellular proliferation, and metastasis in cellular models of breast cancer. The potential role for AHR in SERM pharmacology was further underscored by the ability of 4OHT to suppress osteoclast differentiation in vitro in part through AHR. Cumulatively, these findings provide evidence that it is necessary to reevaluate the relative roles of ER and AHR in manifesting the pharmacological actions and therapeutic efficacy of TAM and other SERMs.
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