DNA methylation of estrogen regulated enhancers defines endocrine sensitivity in breast cancer
Ontology highlight
ABSTRACT: Expression of estrogen receptor (ESR1) determines whether a breast cancer patient receives endocrine therapy as part of their adjuvant care, but does not guarantee patient response. However, the molecular factors that define endocrine response in ESR1-positive breast cancer patients remain poorly understood. Here, we characterize the DNA methylome of endocrine sensitivity and demonstrate the potential impact of differential DNA methylation on endocrine response in breast cancer. We show that DNA hypermethylation occurs predominantly at estrogen-responsive enhancers and is associated with reduced ESR1 binding and decreased gene expression of key regulators of ESR1-activity; thus providing a novel mechanism by which endocrine response is abated in ESR1-positive breast cancers. Conversely, we delineate that ESR1-responsive enhancer hypomethylation is critical in transition from normal mammary epithelial cells to endocrine responsive ESR1-positive cancer. Cumulatively these novel insights highlight the potential of ESR1-responsive enhancer methylation to both predict ESR1-positive disease and stratify ESR1-positive breast cancer patients as responders to endocrine therapy.
Project description:Expression of estrogen receptor (ESR1) determines whether a breast cancer patient receives endocrine therapy as part of their adjuvant care, but does not guarantee patient response. However, the molecular factors that define endocrine response in ESR1-positive breast cancer patients remain poorly understood. Here, we characterize the DNA methylome of endocrine sensitivity and demonstrate the potential impact of differential DNA methylation on endocrine response in breast cancer. We show that DNA hypermethylation occurs predominantly at estrogen-responsive enhancers and is associated with reduced ESR1 binding and decreased gene expression of key regulators of ESR1-activity; thus providing a novel mechanism by which endocrine response is abated in ESR1-positive breast cancers. Conversely, we delineate that ESR1-responsive enhancer hypomethylation is critical in transition from normal mammary epithelial cells to endocrine responsive ESR1-positive cancer. Cumulatively these novel insights highlight the potential of ESR1-responsive enhancer methylation to both predict ESR1-positive disease and stratify ESR1-positive breast cancer patients as responders to endocrine therapy. Methylation profiling with Illumina's HumanMethylation450K array was performed on ESR1-positive hormone sensitive MCF7 cells, and three different well characterised endocrine resistant MCF7-derived cell lines; tamoxifen-resistant (TAMR), fulvestrant-resistant (FASR) and estrogen deprivation resistant (MCF7X) cells. For each cell line two biological replicates were profiled bringing the number of samples to eight.
Project description:Estrogen signaling in breast cancer cells relies on long-range chromatin interactions connecting distal regulatory elements bound by the estrogen receptor 1 (ESR1) to target gene promoters. This ensures stimulus and subtype-specific transcriptional responses. Expanding on the function of CTCF and the cohesin complex in breast cancer, we demonstrate that the chromatin-looping factor ZNF143 binds the promoter of most early-response estrogen target genes connected to distal regulatory elements in ESR1-positive breast cancer cells. Its chromatin occupancy is unaffected by estrogen stimulation, supporting a stable three-dimensional genomic architecture within the early response to estrogen. Its loss abrogates the estrogen-induced transcriptional response and growth of breast cancer cells. When taking into account CTCF, ZNF143 and cohesin complex subunits, we show that chromatin-looping factors are genetically altered in over 20% of ESR1-positive primary breast tumors. Furthermore, the overexpression of ZNF143, CTCF and RAD21, a cohesin complex subunit, in ESR1-positive breast tumors associates with a worse clinical outcome. Overall, our results suggest that ZNF143 is a new critical effector of the estrogen response and highlights the contribution of the chromatin looping machinery to ESR1-positive breast cancer development. Examination of genome-wide ZNF143 binding in MCF-7 cells
Project description:Estrogen signaling in breast cancer cells relies on long-range chromatin interactions connecting distal regulatory elements bound by the estrogen receptor 1 (ESR1) to target gene promoters. This ensures stimulus and subtype-specific transcriptional responses. Expanding on the function of CTCF and the cohesin complex in breast cancer, we demonstrate that the chromatin-looping factor ZNF143 binds the promoter of most early-response estrogen target genes connected to distal regulatory elements in ESR1-positive breast cancer cells. Its chromatin occupancy is unaffected by estrogen stimulation, supporting a stable three-dimensional genomic architecture within the early response to estrogen. Its loss abrogates the estrogen-induced transcriptional response and growth of breast cancer cells. When taking into account CTCF, ZNF143 and cohesin complex subunits, we show that chromatin-looping factors are genetically altered in over 20% of ESR1-positive primary breast tumors. Furthermore, the overexpression of ZNF143, CTCF and RAD21, a cohesin complex subunit, in ESR1-positive breast tumors associates with a worse clinical outcome. Overall, our results suggest that ZNF143 is a new critical effector of the estrogen response and highlights the contribution of the chromatin looping machinery to ESR1-positive breast cancer development. mRNA profiles of MCF-7 cells (siCtl or siZNF143) under vehicle (EtOH) or E2 (10 uM 17-beta oestradiol) stimulation
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:Estrogen signaling in breast cancer cells relies on long-range chromatin interactions connecting distal regulatory elements bound by the estrogen receptor 1 (ESR1) to target gene promoters. This ensures stimulus and subtype-specific transcriptional responses. Expanding on the function of CTCF and the cohesin complex in breast cancer, we demonstrate that the chromatin-looping factor ZNF143 binds the promoter of most early-response estrogen target genes connected to distal regulatory elements in ESR1-positive breast cancer cells. Its chromatin occupancy is unaffected by estrogen stimulation, supporting a stable three-dimensional genomic architecture within the early response to estrogen. Its loss abrogates the estrogen-induced transcriptional response and growth of breast cancer cells. When taking into account CTCF, ZNF143 and cohesin complex subunits, we show that chromatin-looping factors are genetically altered in over 20% of ESR1-positive primary breast tumors. Furthermore, the overexpression of ZNF143, CTCF and RAD21, a cohesin complex subunit, in ESR1-positive breast tumors associates with a worse clinical outcome. Overall, our results suggest that ZNF143 is a new critical effector of the estrogen response and highlights the contribution of the chromatin looping machinery to ESR1-positive breast cancer development.
Project description:Estrogen signaling in breast cancer cells relies on long-range chromatin interactions connecting distal regulatory elements bound by the estrogen receptor 1 (ESR1) to target gene promoters. This ensures stimulus and subtype-specific transcriptional responses. Expanding on the function of CTCF and the cohesin complex in breast cancer, we demonstrate that the chromatin-looping factor ZNF143 binds the promoter of most early-response estrogen target genes connected to distal regulatory elements in ESR1-positive breast cancer cells. Its chromatin occupancy is unaffected by estrogen stimulation, supporting a stable three-dimensional genomic architecture within the early response to estrogen. Its loss abrogates the estrogen-induced transcriptional response and growth of breast cancer cells. When taking into account CTCF, ZNF143 and cohesin complex subunits, we show that chromatin-looping factors are genetically altered in over 20% of ESR1-positive primary breast tumors. Furthermore, the overexpression of ZNF143, CTCF and RAD21, a cohesin complex subunit, in ESR1-positive breast tumors associates with a worse clinical outcome. Overall, our results suggest that ZNF143 is a new critical effector of the estrogen response and highlights the contribution of the chromatin looping machinery to ESR1-positive breast cancer development.
Project description:RNA sequencing (RNA-seq) detects estrogen receptor alpha gene (ESR1) fusion transcripts in estrogen receptor positive (ER+) breast cancer but their role in disease pathogenesis remains unclear. Herein we examined multiple in-frame and out-of-frame ESR1 fusions and found that two, both identified in advanced endocrine treatment resistant disease, encoded stable and functional in-frame fusion proteins. In both examples, ESR1-e6>YAP1 and ESR1-e6>PCDH11X, the N-terminal, DNA binding and dimerization motifs encoded by exons 2-6 were fused to C terminal sequences from the partner gene. Functional properties included estrogen-independent growth, constitutive expression of ER target genes, anti-estrogen resistance, induction of cellular motility in vitro and the development of lung metastasis in vivo. Chromatin immunoprecipitation and RNA sequencing experiments showed both fusions uniquely activated a metastasis-associated transcriptional program. ESR1-e6>YAP1 and ESR1-e6>PCDH11X-induced growth remained sensitive to a CDK4/6 inhibitor, palbociclib, and a patient-derived xenograft (PDX) naturally expressing the ESR1-e6>YAP1 fusion was also responsive. Transcriptionally active ESR1 fusions therefore trigger both endocrine therapy resistance and metastatic progression explaining the association with fatal disease progression, although CDK4/6 inhibitor treatment is predicted to be effective.
Project description:Estrogen and estrogen receptor (ER) signaling play critical roles in the development of ER-positive breast cancer, and endocrine therapy is the frontline treatment for ER-positive breast cancer patients. However, the primary and acquired resistance to endocrine therapy including tamoxifen and fulvestrant remains as the major challenge in the clinic. Here, we identified an estrogen-induced lncRNA, LINC02568, through transcriptomic analysis, which is highly expressed in ER-positive breast cancer. LINC02568 is functional important in ER-positive breast cancer cell growth in vitro and tumorigenesis in vivo as well as endocrine therapy resistance. Mechanically, we demonstrated that LINC02568 regulates, in trans, estrogen/ERα-induced gene transcriptional activation by sponging miR-1233-5p to stabilize ESR1 mRNA in the cytoplasm. Meanwhile, LINC02568 contributes to tumor-specific pH homeostasis in breast cancer cells by regulating CA12 in cis in the nucleus. The dual functions of LINC02568 together contribute to breast cancer cell growth and tumorigenesis as well as endocrine therapy resistance. Antisense oligonucleotides (ASO) targeting LINC02568 significantly inhibits ER-positive breast cancer cell growth in vitro and tumorigenesis in vivo as well as resensitize tamoxifen-resistant cells to tamoxifen. Furthermore, combination treatment with ASO targeting LINC02568 and tamoxifen exhibits synergistic effect on tumor growth. Taken together, our findings revealed dual mechanisms of LINC02568 in regulating ERα signaling and pH homeostasis in ER-positive breast cancer, and indicated that targeting LINC02568 might represent a potential therapeutic avenue in clinic.
Project description:Recent analyses have identified heterogeneity in estrogen receptor (ER)-positive breast cancer. There are so-called luminal A and luminal B subtypes, and the characteristics, such as response to endocrine therapy and chemotherapy and prognosis, are different in these two subtypes of breast cancer. In this study, expression profiles of microRNAs (miRNAs) and mRNAs in ER-positive breast cancer tissues were compared between highly and incompletely endocrine responsive tumors by miRNA and mRNA microarrays. Unsupervised hierarchical clustering analyses revealed distinct expression patterns of miRNAs and mRNAs in these two groups. We identified one miRNA that was downregulated in highly endocrine responsive tumors and 8 miRNAs that were downregulated in incompletely endocrine responsive tumors, and target genes of these miRNAs were predicted using TargetScan and MiRanda. Protein expression patterns of the predicted target genes and the genes that were identified by mRNA expression profiling were analyzed in ER-positive breast cancer samples by immunohistochemistry. We identified a novel protein that might be associated with characteristics of ER-positive breast cancer.
Project description:Recent analyses have identified heterogeneity in estrogen receptor (ER)-positive breast cancer. There are so-called luminal A and luminal B subtypes, and the characteristics, such as response to endocrine therapy and chemotherapy and prognosis, are different in these two subtypes of breast cancer. In this study, expression profiles of microRNAs (miRNAs) and mRNAs in ER-positive breast cancer tissues were compared between highly and incompletely endocrine responsive tumors by miRNA and mRNA microarrays. Unsupervised hierarchical clustering analyses revealed distinct expression patterns of miRNAs and mRNAs in these two groups. We identified one miRNA that was downregulated in highly endocrine responsive tumors and 8 miRNAs that were downregulated in incompletely endocrine responsive tumors, and target genes of these miRNAs were predicted using TargetScan and MiRanda. Protein expression patterns of the predicted target genes and the genes that were identified by mRNA expression profiling were analyzed in ER-positive breast cancer samples by immunohistochemistry. We identified a novel protein that might be associated with characteristics of ER-positive breast cancer.