ERα/PR crosstalk is altered in the context of the ERα Y537S mutation and contributes to endocrine therapy-resistant tumor proliferation
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PROVIDER: PRJNA1018519 | ENA |
REPOSITORIES: ENA
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Project description:Background: The constitutively active ESR1 Y537S mutation is associated with endocrine therapy resistance and progression of metastatic breast cancer through its effects on estrogen receptor (ERα) gene regulatory functions. However, the complex relationship between ERα and the progesterone receptor (PR), known as ERα/PR crosstalk, has yet to be characterized in the context of the ERα Y537S mutation. This study aimed to elucidate the effects of the ERα Y537S mutation on ERα/PR crosstalk and resultant transcriptional activity and to identify potential therapeutic sensitivities that may offer novel treatment options to patients with endocrine therapy-resistant breast cancer. Methods: Proximity-based interactions of ERα and PR were assessed via proximity ligation assay (PLA). Gene expression in MCF7 and T47D cells was assessed by RNA-seq analysis with comparison to publicly available patient tumor transcriptome data. Chromatin immunoprecipitation (ChIP)-qPCR and immunoblotting were used to assess ERα/PR-associated gene expression and protein expression, respectively. Data were analyzed by ordinary two-way ANOVA (α = 0.05) with Tukey’s multiple comparisons tests. Results: Physical interaction of ERα and PR was increased in the context of the ERα Y537S mutation, including in the nucleus where this interaction may translate to altered gene expression. As such, more than 30 genes were differentially expressed in both patient tumor and cell line data (MCF7 and/or T47D cells) in the context of the ERα Y537S mutation compared to ERα WT. Of these, IRS1 stood out as a gene of interest, and ERα and PR occupancy at chromatin binding sites along IRS1 were uniquely altered in the context of ERα Y537S. Furthermore, siRNA knockdown of IRS1 or treatment with the IRS1 inhibitor NT-157 indicated a significant anti-proliferative effect of IRS1 depletion or inhibition in ERα Y537S cell lines. Conclusions: Previous research has characterized gene regulatory changes associated with the ERα Y537S mutation from the viewpoint of ERα. Here, we identify consequential changes to both ERα and PR transcription factor activity, including at chromatin binding sites for the signaling adaptor protein IRS1. We identified a significant dependence of ERα Y537S-expressing cells on IRS1 for proliferation, implicating IRS1 as a potential therapeutic target for restoring treatment sensitivity to patients with breast cancers harboring ERα Y537S mutations.
2023-09-20 | GSE243454 | GEO
Project description:Abstract Several endocrine therapy (ET) resistance mechanisms for ER-positive (ER+) breast cancer (BC) have been proposed, including acquired ESR1 (ERα gene) mutations. The two most common ESR1 mutations are Y537S and D538G, which give rise to a constitutively active receptor with reduced affinity for agonists and antagonists. The discovery of new effective therapies remains a significant challenge in treating mutated ER+ BC. In this context, Poly (ADP-ribose) polymerase-1 (PARP-1) has captured considerable interest as a target for therapeutic inhibitors in specific types of cancers. Here, we report that crosstalk between PARP-1 and ERα may represent a novel therapeutic approach for ER+ BC. We have demonstrated that the up-regulation of PARP-1 expression, stimulated by 17-β estradiol (E2), was blocked by treatment with fulvestrant (Ful), a potent ERα antagonist, or ESR1 siRNA in ER+ MCF7 and T47D BC cell models that express both wild type ERα and the Y537S mutation, indicating that ERα regulates the expression of PARP-1. In addition, ERα-mediated transcriptional activity depended on PARP-1 activity in these models, as confirmed by ERα target gene expression and ERE reporter gene analyses +/- niraparib (Nira). Notably, PARP-1 modulates the estrogen-dependent genomic binding of ERα and FoxA1, which play a crucial role in the proliferation of ER+ BC. We also showed that PARP-1 inhibition prevented proliferation and cell cycle activities of ERα WT and ERα Y537S cells upon ERα activation. In vivo, Nira and lasofoxifene (Laso), an ERα antagonist, significantly reduced primary tumor growth versus vehicle, both as single agents and in combination. Moreover, RNA-seq analyses demonstrated the downregulation of ERα signaling in the mammary glands of mice treated with Nira versus Vehicle. Our results provide novel insights into the molecular events through which PARP-1 may serve as a more comprehensive therapeutic approach to target ET BC resistance in women with advanced ER+ BC.
2024-09-30 | GSE277883 | GEO
Project description:Estrogen receptor-alpha (ERα) is the driving transcription factor in 70% of breast cancers and its activity is associated with hormone dependent tumor cell proliferation and survival. Given the recurrence of hormone resistant relapses, understanding the etiological factors fueling resistance is of major clinical interest. Hypoxia, a frequent feature of the solid tumor microenvironment, has been described to promote endocrine resistance by triggering ERα down-regulation in both in vitro and in vivo models. Yet, the consequences of hypoxia on ERα genomic activity remain largely elusive. In the present study, transcriptomic analysis shows that hypoxia regulates a fraction of ERα target genes, underlying an important regulatory overlap between hypoxic and estrogenic signaling. This gene expression reprogramming is associated with a massive reor-ganization of ERα cistrome, highlighted by a massive loss of ERα binding sites. Profiling of en-hancer acetylation revealed a hormone independent enhancer activation at the vicinity of genes harboring hypoxia inducible factor (HIFα) binding sites, the major transcription factors governing hypoxic adaptation. This activation counterbalances the loss of ERα and sustains hor-mone-independent gene expression. We describe hypoxia in luminal ERα (+) breast cancer as a key factor interfering with endocrine therapies, associated with poor clinical prognosis in breast cancer patients.
2022-10-06 | GSE111914 | GEO
Project description:Hypoxia and ERα Transcriptional Crosstalk Is Associated with Endocrine Resistance in Breast Cancer
| PRJNA438527 | ENA
Project description:Estrogen receptor alpha (ERα) expression in breast cancer is predictive of response to endocrine therapy, however resistance is common in ERα-positive tumors that over-express the growth factor receptor ERBB2. Even in the absence of estrogen, ERα can be activated by growth factors including the epidermal growth factor (EGF). EGF induces a transcriptional program distinct from estrogen, however the mechanism of the stimulus-specific response is unknown. Here we show that the EGF-induced ERα genomic targets, its cistrome, are distinct from those induced by estrogen in a process dependent on the transcription factor AP-1. The EGF-induced ERα cistrome specifically regulates genes found over-expressed in ERBB2-positive human breast cancers. This provides a potential molecular explanation for the endocrine therapy resistance seen in ERα-positive breast cancers that over-express ERBB2. These results suggest a central role for ERα in hormone-refractory breast tumors dependent on growth factor pathway activation and favors the development of therapeutic strategies completely antagonizing ERα as opposed to blocking its estrogen responsiveness alone.
2010-12-29 | GSE26081 | GEO
Project description:The molecular mechanisms of endocrine resistance in breast cancer remain poorly understood. Here we used PRO-seq to map the location of hundreds of genes and thousands of distal enhancers whose activities differ between endocrine sensitive and resistant MCF-7 cells. Our genome-wide screen identified a 16-fold transcriptional increase in glial-cell line derived neurotrophic factor (GDNF), a RET tyrosine kinase receptor ligand, which is both necessary and sufficient for resistance in MCF-7 cells. GDNF causes endocrine resistance by switching the active state of a bi-stable feedback loop from ERα signaling to GDNF-RET signaling. To catalyze this switch, we found that GDNF directly downregulates ERα transcription and activates the transcription factor EGR1, which, in turn, induces GDNF expression. Remarkably, both MCF-7 cells and ER+ primary tumors appear poised for endocrine resistance via the RET signaling pathway, but lack robust RET ligand expression and only develop resistance upon expression of GDNF or other RET ligands.
2018-02-22 | GSE93229 | GEO
Project description:There is clinical need to predict sensitivity of metastatic hormone receptor-positive and HER2-negative (HR+/HER2-) breast cancer to endocrine therapy, and targeted RNA sequencing (RNAseq) offers diagnostic potential to measure both transcriptional activity and functional mutation. We developed the SET ER/PR index to measure gene expression microarray probe sets that were correlated with hormone receptors (ESR1 and PGR) and robust to pre-analytical and analytical influences. We tested SET ER/PR index in biopsies of metastastic HR+/HER2- breast cancer against the treatment outcomes in 140 patients. Then we customized the SETER/PR assay to measure 18 informative, 10 reference transcripts, and sequence the ligand binding domain (LBD) of ESR1 using droplet-based targeted RNAseq, and tested that in residual RNA from 53 patients. Higher SET ER/PR index in metastatic samples predicted longer progression-free (PFS) and overall survival (OS) when patients received endocrine therapy as next treatment, even after adjustment for clinical-pathologic risk factors (PFS: HR 0.534, 95% CI 0.299 to 0.955, p = 0.035; OS: HR 0.315, 95% CI 0.157 to 0.631, p = 0.001). Mutated ESR1 LBD was detected in 8/53 (15%) of metastases, involving 1% to 98% of ESR1 transcripts (all had high SETER/PR index). A signature based on probe sets with good pre-analytical and analytical performance facilitated our customization of an accurate targeted RNAseq assay to measure both phenotype and genotype of ER-related transcription. Elevated SET ER/PR was associated with prolonged sensitivity to endocrine therapy in patients with metastatic HR+/HER2- breast cancer, especially in the absence of mutated ESR1 transcript. We tested SET ER/PR index in biopsies of metastastic HR+/HER2- breast cancer against the treatment outcomes in 140 patients. Then we customized the SET ER/PR assay to measure 18 informative, 10 reference transcripts, and sequence the ligand binding domain (LBD) of ESR1 using droplet-based targeted RNAseq, and tested that in residual RNA from 53 patients. Higher SET ER/PR index in metastatic samples predicted longer progression-free (PFS) and overall survival (OS) when patients received endocrine therapy as next treatment, even after adjustment for clinical-pathologic risk factors (PFS: HR 0.485, 95% CI 0.265 to 0.889, p = 0.019; OS: HR 0.314, 95% CI 0.155 to 0.637, p = 0.001). Mutated ESR1 LBD was detected in 8/53 (15%) of metastases, involving 1% to 98% of ESR1 transcripts (all had high SET ER/PR index). A signature based on probe sets with good pre-analytical and analytical performance facilitated our customization of an accurate targeted RNAseq assay to measure both phenotype and genotype of ER-related transcription. Elevated SET ER/PR was associated with prolonged sensitivity to endocrine therapy in patients with metastatic HR+/HER2- breast cancer, especially in the absence of mutated ESR1 transcript.
2019-05-30 | GSE124647 | GEO
Project description:There is clinical need to predict sensitivity of metastatic hormone receptor-positive and HER2-negative (HR+/HER2-) breast cancer to endocrine therapy, and targeted RNA sequencing (RNAseq) offers diagnostic potential to measure both transcriptional activity and functional mutation. We developed the SETER/PR index to measure gene expression microarray probe sets that were correlated with hormone receptors (ESR1 and PGR) and robust to pre-analytical and analytical influences. We tested SETER/PR index in biopsies of metastastic HR+/HER2- breast cancer against the treatment outcomes in 140 patients. Then we customized the SETER/PR assay to measure 18 informative, 10 reference transcripts, and sequence the ligand binding domain (LBD) of ESR1 using droplet-based targeted RNAseq, and tested that in residual RNA from 53 patients. Higher SETER/PR index in metastatic samples predicted longer progression-free (PFS) and overall survival (OS) when patients received endocrine therapy as next treatment, even after adjustment for clinical-pathologic risk factors (PFS: HR 0.534, 95% CI 0.299 to 0.955, p = 0.035; OS: HR 0.315, 95% CI 0.157 to 0.631, p = 0.001). Mutated ESR1 LBD was detected in 8/53 (15%) of metastases, involving 1% to 98% of ESR1 transcripts (all had high SETER/PR index). A signature based on probe sets with good pre-analytical and analytical performance facilitated our customization of an accurate targeted RNAseq assay to measure both phenotype and genotype of ER-related transcription. Elevated SETER/PR was associated with prolonged sensitivity to endocrine therapy in patients with metastatic HR+/HER2- breast cancer, especially in the absence of mutated ESR1 transcript.
2019-05-30 | GSE124648 | GEO
Project description:Why breast cancers become resistant to tamoxifen despite continued expression of the estrogen receptor alpha (ERα) and what factors are responsible for high HER2 expression in these tumors remains an enigma. HOXB7 ChIP analysis followed by validation showed that HOXB7 physically interacts with ERα, and that the HOXB7-ERα complex enhances transcription of many ERα target genes including HER2. Investigating strategies for controlling HOXB7, our studies revealed that MYC, stabilized via phosphorylation mediated by EGFR-HER2 signaling, inhibits transcription of miRNA-196a, a HOXB7 repressor. This leads to increased expression of HOXB7, ER-target genes and HER2. Repressing MYC using small molecule inhibitors reverses these events, and causes regression of breast cancer xenografts. The MYC-HOXB7-HER2 signaling pathway is eminently targetable in endocrine-resistant breast cancer.
2014-11-25 | GSE63607 | GEO
Project description:Estrogen Receptor alpha (ERα), a nuclear receptor with transcriptional activity, is a master regulator of estrogen signaling, widely known as therapeutic target in hormone-responsive breast cancer (BC). Moreover, ERα is highly expressed in approximately 80% of High Grade Serous Ovarian Cancer (HGSOC), the most common epithelial ovarian carcinoma. Despite some promising clinical trials evaluating endocrine therapy in this type of tumor, the role of ERα is still unknown. Epigenetic changes, such as DNA methylation, are emerging as key contributing factors to carcinogenesis. Disruptor of telomeric silencing-1-like (DOT1L), the only known histone methyl transferase capable to produce H3K79 mono, di and tri-methylation, modulates ERα actions in hormone-responsive BC. Considering this evidence, ERα-DOT1L association was confirmed in ERα-positive OC cells, PEO1 and PEO4, by Co-IP. DOT1L pharmacological inhibition by EPZ004777 (EPZ) revealed the involvement of this epigenetic enzyme in cell proliferation, cell cycle progression and apoptosis. Transcriptome profiling after ICI (a Selective Estrogen Receptor Degrader) and EPZ treatment, in both cell lines, has underlined a deep impact of both compounds on ERα-modulated genes, including the down-regulation of ERα itself. On the other hand, functional analysis showed that commonly affected transcripts are involved in different cellular processes, such as cancer cell survival, chemoresistance and cell cycle progression. Moreover, ChIP-qPCR performed on ERα promoter highlighted ERα and DOT1L co-localization, both in PEO1 and in PEO4 cells, which was reduced after EPZ treatment, suggesting a role of this complex on receptor transcriptional activity. In addition, drug combination studies performed with EPZ and ICI showed an additive effect in cell growth inhibition. Taken together, these results suggest DOT1L as a potential therapeutic target in the treatment of OC.
2019-11-04 | E-MTAB-8198 | biostudies-arrayexpress