Project description:This study is designed to comprehensively characterize the FOXA1 cistromes of Y537S and D538G mutated ER versus WT ER in breast cancer cells.
Project description:This study is designed to comprehensively characterize the cistromes of Y537S and D538G mutated ER versus WT ER in breast cancer cells. Genome-edited MCF7 and T47D cells were hormone deprived and treated with or without E2 for 45 minuts. Chromatin DNA was then extracted from each sample. The immunoprecipitation was performed using ERα (Santa Cruz Biotechnologies, sc543) antibody. Pooled DNA samples from individual clones were sent to sequencing with Illumina Hiseq 2500 Platform. ChIP-seq reads were aligned to either hg38 genome assembly using Bowtie 2.0, and peaks were called using MACS2.0 with p value below 10E-5. DiffBind was used to perform principle component analysis, identify differentially expressed binding sites and analyze intersection ratios with other data sets. Genomic feature distribution were called using ChIPseeker.
Project description:Gene expression profiling of the downstream transcriptional changes induced by ESR1 fusion genes observed in human breast tumors resistant to hormone therapy Experimental T47D cells stably expressing ESR1 fusion genes (or T47D cells treated with estradiol) vs. T47D cells expressing YFP
Project description:Purpose: Transcriptome analysis of ESR1 mutant cells was performed via sequencing total RNA in T47D and MCF7 cell lines containing Y537S and D538G mutations.
Project description:Transcriptionally active ESR1 fusions promote endocrine therapy (ET)-resistant growth and metastasis of estrogen receptor-alpha positive (ERα+) breast cancer. Currently, there are no targeted treatment options for tumors harboring active fusions because the ESR1 ligand binding domain (LBD) has been replaced with non-drug binding sequences from the 3’ partner gene. A mass spectrometry (MS)-based Kinase Inhibitor Pulldown Assay (KIPA) demonstrated an increase of multiple receptor tyrosine kinases including RET in T47D cells expressing active ESR1 fusions. Integrated proteogenomics defined tumor subsets that could be responsive to RET and CDK4/6 directed therapy from 22 biologically heterogeneous ERα+ patient-derived xenograft (PDX) tumors. Inhibition of RET by repurposing an FDA-approved drug significantly suppressed ESR1 fusion-driven growth of cell, PDX-derived organoid (PDXO) and PDX models. CDK4/6 inhibitor treatment showed similar tumor reductions to RET inhibition. Here, we reveal therapeutic kinase vulnerabilities in ESR1 fusion-driven tumors, which will lay the framework for future clinical trials.
Project description:Aberrant activation of the forkhead protein FOXA1 is observed in advanced hormone-related cancers. However, to date, key mediators of high FOXA1 signaling remain elusive. We demonstrate that ectopic high FOXA1 (H-FOXA1) expression promotes estrogen receptor-positive (ER+) breast cancer (BC) metastasis in a xenograft mouse model. Mechanistically, H-FOXA1 reprograms ER-chromatin binding to elicit a core gene signature (CGS) highly enriched in ER+ endocrine-resistant (EndoR) cells. We identified Secretome14, a CGS subset encoding ER-dependent cancer secretory proteins, strongly predicts poor outcomes of ER+ BC and is elevated in ER+ metastases vs. primary tumors, irrespective to the ESR1 mutations. Parental (P) ER+ BC cells and their endocrine-resistant (EndoR) derivatives, and ER+ BC cells expressing doxycycline (Dox)-inducible ectopic FOXA1 were used in this study. Differential gene expression analysis was performed in EndoR vs. P cells and P cells +Dox vs. -Dox. We found that the FOXA1-CGS was highly enriched in the altered transcriptomes of two ER+ BC cell models (ZR75-1 and T47D) expressing ectopic H-FOXA1. The enriched hallmark gene sets, shared by the H-FOXA1 cell models, include “inflammatory response”, “complement”, and “interferon gamma response” for the H-FOXA1-induced, and “estrogen response early” and “estrogen response late” for the H-FOXA1-repressed genes. These findings point to the common transcriptional profile exhibiting an immune- over estrogen-responsive signature induced by H-FOXA1. In addition, we found that both the tamoxifen-resistant (TamR) and estrogen deprivation-resistant (EDR) derivatives of the 600MPE P cells were enriched for the H-FOXA1-induced CGS and FOXA1/ER-activated Secretome14. Our findings uncover H-FOXA1-induced ER reprogramming driving EndoR and metastasis, possibly via a H-FOXA1/ER-dependent secretome that warrants further studies to clarify its involvement in disease progression of ER+ metastatic BC.
Project description:Breast cancer is a heterogeneous disease comprised of at least five major subtypes. Luminal subtype tumors confer a more favourable patient prognosis, which is in part, attributed to the Estrogen Receptor-alpha (ER) positivity and anti-hormone responsiveness of these tumors. Expression of the forkhead box transcription factor, FOXA1, also correlates with the luminal subtype and patient survival, but is present in a subset of ER-negative tumors. Similarly, FOXA1 is consistently expressed in luminal breast cancer cell lines even in the absence of ER. In contrast, basal breast cancer cell lines do not express FOXA1, and loss of FOXA1 in luminal cells increases migration and invasion, characteristics of the basal subtype. To delineate an ER-independent role for FOXA1 in maintaining the luminal phenotype, and hence a more favourable prognosis, we performed cDNA microarray analyses on luminal FOXA1-positive, ER-positive (MCF7, T47D) and FOXA1-positive, ER-negative (MDA-MB-453, SKBR3) cell lines in the presence or absence of transient FOXA1 silencing. This resulted in three FOXA1 transcriptomes: (1) a luminal-signature (consistent across cell lines), (2) an ER-positive signature (restricted to MCF7 and T47D) and (3) an ER-negative signature (restricted to MDA-MB-453 and SKBR3). Use of Gene Set Enrichment Analyses (GSEA) as a phenotyping tool revealed that FOXA1 silencing resulted in a transcriptome shift from luminal to basal gene expression signatures. FOXA1 binds to both luminal and basal genes within luminal breast cancer cells, suggesting that it not only transactivates luminal genes, but also represses basal-associated genes. From these results we conclude that FOXA1 controls plasticity between basal and luminal cells, playing a dominant role in repressing the basal phenotype, and thus tumor aggressiveness, in luminal breast cancer cells. Although it has been proposed that FOXA1-targeting agents may be useful for treating luminal tumors, these data suggest that this approach may promote transitions toward a more aggressive cancer. FOXA1 siRNA treated breast cell lines compared directly to nonspecific siRNA treated cell lines using Agilent 4X44 microarrays.
Project description:Heat shock factor 1 (HSF1) is a key regulator of transcriptional responses to proteotoxic stress. It has been recently linked to signaling of estrogen via ESR1. To study the cooperation of HSF1 and ESR1 in the transcriptional response to estrogen, we established estrogen receptor (ER)-positive breast cancer cell lines with reduced HSF1 levels using specific shRNA or CRISPR/Cas9 approach. HSF1 deficiency led to the inhibition of the mitogenic effect of estrogen in MCF7 and T47D cells. RNA-seq analyses revealed that the stimulatory effect of E2 on the transcriptome was smaller in HSF1-deficient MCF7 cells. This could partially result from the higher basal expression of E2-dependent genes in these cells as a consequence of the enhanced binding of unliganded ESR1 to chromatin, which was revealed by ChIP-seq analyses. Thus, we postulate that some fraction of ESR1 could be released from the inhibitory complex with HSP90 and gain transcriptional competence without E2-stimulation.