Time-resolved DNA methylation profiling of endocrine resistance in the T47D luminal A breast cancer cell line
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE154626 | GEO | 2020/07/17
REPOSITORIES: GEO
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Project description:The ETS transcription factor ELF5 drives mammary alveolar development in preparation for lactation by forcing differentiation within the progenitor cell population. In luminal A breast cancer, early disease progression is predicted by high levels of ELF5, and in preclinical models elevated ELF5 is associated with its two key features, the acquisition of resistance to endocrine therapy and increased metastasis. We first created an MCF7 cell line with doxycycline-inducible ELF5 and then examined with ChIP-seq differences in genomic binding of FOXA1, ER and H3K4me3 upon doxycycline treatment, compared to vehicle. In addition we performed RNA-seq experiments to examine changes in gene expression upon induction of ELF5 expression. Here we demonstrate that ELF5 binding overlaps with FOXA1 and ER at enhancers and promoters, and when elevated causes FOXA1 and ER to bind to new regions of the genome involved in resistance to endocrine therapy. RNA-seq demonstrated that these changes altered gene expression to diminish estrogen influence, and that ELF5 regulated the expression of ER transcription-complex genes. These data show that ELF5 modulated estrogen-driven transcription in breast cancer by directing FOXA1 and ER to new genomic locations, and by interaction with, and regulation of, members of the ER transcriptional complex. This provides a mechanistic basis for the influence of ELF5 on the progression of luminal breast cancer to endocrine insensitivity.
2020-01-06 | E-MTAB-7641 | biostudies-arrayexpress
Project description:Tamoxifen is the treatment of choice in estrogen receptor alpha breast cancer patients. However, ~50% of ERα-positive tumors exhibit intrinsic or rapidly acquire resistance to endocrine treatment, requiring chemotherapy. Ιt has been difficult to predict de novo resistance to endocrine therapy and/or assess the likelihood of early relapse, while no concrete mechanism regulating the acquisition and the maintenance of endocrine resistance has been identified. We have performed a whole transcriptome analysis of an ER-positive (T47D) and a triple-negative (MDA-MBA-231) breast cancer cell line exposed to tamoxifen for a short time frame (hours) in order to study resistance mechanisms that are initiated early after initiation of tamoxifen treatment.
2014-08-29 | GSE60879 | GEO
Project description:Tamoxifen is the treatment of choice in estrogen receptor alpha breast cancer patients. However, ~50% of ERα-positive tumors exhibit intrinsic or rapidly acquire resistance to endocrine treatment, requiring chemotherapy. Ιt has been difficult to predict de novo resistance to endocrine therapy and/or assess the likelihood of early relapse, while no concrete mechanism regulating the acquisition and the maintenance of endocrine resistance has been identified. We have performed a whole transcriptome analysis of an ER-positive (T47D) and a triple-negative (MDA-MBA-231) breast cancer cell line exposed to tamoxifen for a short time frame (hours) in order to study resistance mechanisms that are initiated early after initiation of tamoxifen treatment.
2014-08-29 | GSE60878 | GEO
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.
2023-09-13 | GSE217190 | GEO
Project description:*** This submission includes RNA data, with DNA files available under a different accession number*** Purpose: Endocrine therapy resistance remains the greatest challenge for treating hormone receptor positive breast cancer patients. We aim to identify molecular mechanisms underlying endocrine therapy resistance through in-depth genomic analysis of patient samples. Experimental Design: We collected tumors from 35 estrogen receptor positive breast cancer patients receiving endocrine therapy, of which 3 patients had intrinsic resistance and 19 patients developed acquired resistance. For each patient, multiple tumor specimens were collected during the course of treatment. We performed DNA whole exome sequencing and RNA sequencing on all tumor samples. DNA mutations, copy number alterations and RNA gene expression data were analyzed through supervised analyses comparing paired sensitive and resistant tumor samples to identify molecular features related to endocrine therapy resistance. Results: We identified mutations enriched in resistant tumors including ESR1 and GATA3. ESR1 D538G variant confers endocrine therapy resistance while E380Q variant confers hypersensitivity. We demonstrate that resistant tumors had distinct gene expression profiles and elevated signaling pathways including ER, HER2, GATA3, AKT, RAS and p63 signaling. Integrated analysis for individual patient highlighted the heterogeneity of endocrine therapy resistance mechanisms. Conclusions: Our results suggest that mechanisms underlying endocrine therapy resistance are highly heterogeneous with diverse changes in genomic and transcriptomic levels.
2022-09-01 | E-MTAB-9917 | biostudies-arrayexpress
Project description:One of the greatest advances in therapy of estrogen receptor positive breast cancer has been the development of endocrine therapy. More than two thirds of primary breast tumors express estrogen receptor alpha (ERα) and their growth is mainly dependent on estrogen receptor activity. Several therapeutic approaches have thus been designed to inhibit ER activity in breast tissue. Tamoxifen, a selective ER modulator, is one of the main treatment options for premenopausal women with advanced ER positive breast cancer, and has also become well established as adjuvant therapy in the early breast cancer setting (Davies et al., 2011; Group, 1998; Jaiyesimi et al., 1995). In contrast to tamoxifen, which in other tissues such as bone and endometrium, can exert partial agonistic activity (Braithwaite et al., 2003; Fisher et al., 1994; Pietras, 2006), the selective ER downregulator, fulvestrant, is a potent ER antagonist. Binding of fulvestrant to ER inhibits receptor dimerization and nuclear uptake, prevents estrogen-response element binding and accelerates ER degradation (Dauvois et al., 1993; Dowsett et al., 2005; Fawell et al., 1990; Wakeling et al., 1991). Fulvestrant is approved for treatment of postmenopausal women with advanced breast cancer who have relapsed or progressed on first-line endocrine therapy (Howell et al., 2002; Osborne et al., 2002; Robertson et al., 2003). Estrogen deprivation by treatment with aromatase inhibitors (such as letrozole, anastrozole or exemestane) which block synthesis of estrogens is another effective therapy option in postmenopausal women (Bonneterre et al., 2000; Cuzick et al., 2010; Dowsett et al., 2010; Mouridsen et al., 2001; Nabholtz et al., 2000). The large majority of patients with ER+ breast cancer experience an initial response to endocrine therapy, however, in many of these patients, the disease subsequently progresses and eventually anti-estrogen therapy ceases to have effect. Biomarkers predicting response to estrogen deprivation and new alternative treatments targeting the pathways supporting estrogen independent growth are therefore urgently needed (Patani and Martin, 2014; Patani et al., 2013). In order to understand how tumors respond to withdrawal of their main growth signal, a comparison of molecular features of tumor before and during endocrine therapy is necessary, and the fate of individual cancer cell sub-clones should be monitored. Since studies of cellular dynamics are very difficult to perform with clinical material, we made use of a patient derived, estrogen dependent, orthotopically growing luminal-like primary breast cancer xenograft model (PDX) (Bergamaschi et al., 2009; Huuse et al., 2012). This PDX model is a representative model for luminal breast cancers as the molecular characteristics, cellular heterogeneity and estrogen dependency of the primary tumor are retained over many passages. Functionally different subpopulations of cancer cells were previously defined by expression of the markers CD24 and SSEA-4 in this model (Skrbo et al., 2014), and it is therefore a suitable model for comparison of cellular and molecular effects of estrogen deprivation and ER-signaling inhibition. In this study, a quantitative MS-based proteomic analysis using SILAC and a label-free approach were performed, aiming to map changes in protein expression induced by endocrine therapy. Inhibition of ER-signaling seemed to induce CD24 and SSEA-4 expression on residual tumor cells. Proteomic analysis revealed overexpression of enzymes involved in TCA cycle, oxidative phosphorylation and fatty acid beta-oxidation following endocrine treatment when compared to untreated tumors. These results indicated possible reprogramming of cell metabolism and utilization of aerobic respiration, i.e. oxidative phosphorylation, in response to endocrine therapy.
2022-02-28 | PXD002352 | Pride
Project description:Postmenopausal breast cancer patients benefit from aromatase inhibitors (AIs) that reduce the levels of estrogens critical for the growth of estrogen receptor (ER)-positive tumors. Unfortunately, many tumors are resistant to AI, and we are only beginning to understand the complex mechanisms underlying treatment resistance. Here we set out to determine whether epigenetic changes could contribute to therapy resistance. For AI-resistance models, we used previously established MCF-7 cell clones, termed C4-12 and long-term estrogen deprivation (LTED), that were isolated after being cultured in estrogen-free media for 9 months and 18M-bM-^@M-^S24 months, respectively. Methyl CpG Binding Domain (MBD) - pull down followed by affymetrix promoter array was used to detect promoter methylation patterns in these cell lines. These studies identified widespread genomic hyper- and hypomethylation events, with a significant enrichment of promoter hypermethylation of development-associated genes in both cell lines. A developmentally regulated gene that was heavily methylated and lost expression in both cell-line systems was HOXC10. Moreover, we found that HOXC10 is an estrogen-regulated gene and lack of ER regulation is associated with progressive epigenetic silencing through EZH2/H3K27me3 and DNA hypermethylation. Stable knockdown of HOXC10 in MCF-7 cells resulted in increased cell growth, reduced cell apoptosis, and increased cell motility. A preliminary study using AI-treated breast tumors did not show significant associations, however, the numbers were small. We identified HOXC10 methylation as a novel determinant of endocrine resistance. Also, we revealed that epigenetic reprogramming of genes involved in development may be a fundamental phenomenon in hormone resistance. Therefore, our study might provide the basis for the expansion of clinical markers for endocrine resistance and future clinical trials such as combination of endocrine and epigenetic therapies. Long-term estrogen deprived previously established MCF-7 cell clones termed C4-12 and LTED genomic DNA subjected to Methyl CpG Binding Domain (MBD) - pull down followed by affymetrix promoter array to detect promoter methylation patterns
2014-05-01 | E-GEOD-39783 | biostudies-arrayexpress
Project description:Tamoxifen is the treatment of choice in estrogen receptor alpha breast cancer patients. However, ~50% of ERM-NM-1-positive tumors exhibit intrinsic or rapidly acquire resistance to endocrine treatment, requiring chemotherapy. M-NM-^Yt has been difficult to predict de novo resistance to endocrine therapy and/or assess the likelihood of early relapse, while no concrete mechanism regulating the acquisition and the maintenance of endocrine resistance has been identified. We have performed a whole transcriptome analysis of an ER-positive (T47D) and a triple-negative (MDA-MBA-231) breast cancer cell line exposed to tamoxifen for a short time frame (hours) in order to study resistance mechanisms that are initiated early after initiation of tamoxifen treatment. Cells after a 4h incubation with medium containing 10% charcoal stripped FBS were incubated with vehicle,E2 (10-6M) or tamoxifen (10-6M) in RPMI 1640 supplemented with 10% charcoal stripped FBS, for 3 hours. Total RNA was isolated using Nucleospin II columns (Macheray-Nagel, Dttren, Germany), according to the manufacturerM-bM-^@M-^Ys instructions. RNA was labeled and hybridized according to the Affymetrix protocol (Affymetrix Gene-Chip Expression Analysis Technical Manual), using the HGU133A plus 2 chip, analyzing a total of 54675 transcripts. Signals were detected by an Affymetrix microarray chip reader.
2014-08-29 | E-GEOD-60879 | biostudies-arrayexpress
Project description:Tamoxifen is the treatment of choice in estrogen receptor alpha breast cancer patients. However, ~50% of ERM-NM-1-positive tumors exhibit intrinsic or rapidly acquire resistance to endocrine treatment, requiring chemotherapy. M-NM-^Yt has been difficult to predict de novo resistance to endocrine therapy and/or assess the likelihood of early relapse, while no concrete mechanism regulating the acquisition and the maintenance of endocrine resistance has been identified. We have performed a whole transcriptome analysis of an ER-positive (T47D) and a triple-negative (MDA-MBA-231) breast cancer cell line exposed to tamoxifen for a short time frame (hours) in order to study resistance mechanisms that are initiated early after initiation of tamoxifen treatment. Cells after a 4h incubation with medium containing 10% charcoal stripped FBS were incubated with vehicle, E2 (10-6M) or tamoxifen (10-6M) in RPMI 1640 supplemented with 10% charcoal stripped FBS, for 3 hours. Total RNA was isolated using Nucleospin II columns (Macheray-Nagel, Dttren, Germany), according to the manufacturerM-bM-^@M-^Ys instructions. RNA was labeled and hybridized according to the Affymetrix protocol (Affymetrix Gene-Chip Expression Analysis Technical Manual), using the HGU133A plus 2 chip, analyzing a total of 54675 transcripts. Signals were detected by an Affymetrix microarray chip reader.
2014-08-29 | E-GEOD-60878 | biostudies-arrayexpress
Project description:MCM3 is one of several genes whose expression profile is markedly altered in tamoxifen-resistant breast cancer cell lines. We observed that increased MCM3 expression is associated with tamoxifen resistance. Knockdown of MCM3 resulted in increased susceptibility of tamoxifen-resistant breast cancer cell lines. Moreover, MCM3 expression is significantly associated with clinical outcome of endocrine treated receptor positive breast cancer. To understand the effect of MCM3 on the mechanism of endocrine resistance, we performed gene expression array on tamoxifen-resistant breast cancer cell lines. Here we show that MCM3 knockdown affects the expression of hundreds of genes. Resistance to endocrine therapy in estrogen receptor-positive (ER+) breast cancer is a major clinical problem with poorly understood mechanisms. There is an unmet need for prognostic and predictive biomarkers to allow appropriate therapeutic targeting. We evaluated the mechanism by which minichromosome maintenance protein 3 (MCM3) influences endocrine resistance and its predictive/prognostic potential in ER+ breast cancer. We discovered that ER+ breast cancer cells survive tamoxifen and letrozole treatments through upregulation of minichromosome maintenance proteins (MCMs), including MCM3, which are key molecules in cell cycle and DNA replication. Lowering MCM3 expression in endocrine-resistant cells restored drug sensitivity and altered phosphorylation of cell cycle regulators, including p53(Ser315,33), CHK1(Ser317) and cdc25b(Ser323), suggesting that the interaction of MCM3 with cell cycle proteins is an important mechanism of overcoming replicative stress and anti-proliferative effects of endocrine treatments. Evaluation of MCM3 levels in primary tumors from four independent cohorts of breast cancer patients receiving adjuvant tamoxifen mono-therapy or no adjuvant treatment, including the Stockholm tamoxifen (STO-3) trial, showed MCM3 to be an independent prognostic adding information beyond Ki67. In addition, MCM3 was shown to be a predictive marker of response to endocrine treatment. Our study reveals a coordinated signaling network centered around MCM3 that limits response to endocrine therapy in ER+ breast cancer and identifies MCM3 as a clinically useful prognostic and predictive biomarker that allows personalized treatment of ER+ breast cancer patients.
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