MiRNA expression profiling of fulvestrant-treated MCF7 breast cancer cells
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE335697 | GEO | 2026/08/19
REPOSITORIES: GEO
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Project description:Multiple gene expression studies have demonstrated that breast cancer biological diversity is associated with distinct transcriptional programs. Transcription factors, because of their unique ability to coordinate the expression of multiple genes, are speculated to play a role in generating phenotypic plasticity associated with cancer progression including acquired drug resistance. Combinatorial libraries of artificial zinc-finger transcription factors (ZF-TFs) provide a robust means for inducing and understanding various functional components of the cancer phenotype. Herein, we utilized combinatorial ZF-TF library technology to better understand how breast cancer cells acquire resistance to a fulvestrant, a clinically important anti-endocrine therapeutic agent. We isolated six ZF-TF library members capable of inducing stable, long-term anti-endocrine drug-resistance in two independent estrogen receptor positive breast cancer cell lines. Comparative gene expression profile analysis of the ZF-TF-transduced breast cancer cell lines revealed a 72-gene cluster that constituted a common signature for the fulvestrant-resistance phenotype. Pathway enrichment-analysis of gene expression data revealed that the ZF-TF-induced fulvestrant resistance is associated with an estrogen receptor negative-like gene set and four unique myb-regulated gene sets. Furthermore, we identified a set of genes strongly expressed in the ZF-TF-induced fulvestrant-resistant cells that was correlated with a lower probability of distant metastasis-free or death-from-relapse-free survival of breast cancer patients. MCF7-R73 cells, a monoclonal MCF7 subline that is highly sensitive to fulvestrant-induced cytocidal activity, underwent retroviral transduction with the zinc finger transcription factor (ZF-TF) activator library or with a control plasmid encoding only the NF-kB p65 activation domain. Both populations of cells were enriched for transduced cells by selecting for growth in puromycin and for fulvestrant-resistant cells by selecting with 100 nM fulvestrant. After 6 weeks of continuous treatment with fulvestrant, hundreds of drug-resistant colonies emerged from the population of cells infected with the ZF-TF activator library. By contrast, as expected, the control MCF7cell line transduced by NF-kB p65-only underwent massive cell death resulting in the complete absence of resistant colonies. DNA encoding the zinc-finger arrays was rescued by PCR from genomic DNA of pooled fulvestrant-resistant cells. The sequences of the ZF-TFs were determined and 46 unique ZF-TF clones identified. These 46 unique ZF-TFs were re-cloned into the retroviral vector and converted into clonal virus stocks that were used to transduce MCF7-R73 cells. These 46 retrovirally transduced cell populations were then challenged with fulvestrant. As compared with the control MCF-238 cells, MCF7-R73 cells transduced with six unique ZF-TFs demonstrated survival and growth in the presence of 100nM fulvestrant.
2011-07-17 | E-GEOD-27444 | biostudies-arrayexpress
Project description:Estrogen receptor alpha (ERα) and hypoxia-inducible factors (HIFs) are key regulators of transcriptional programmes in breast cancer. To investigate their interplay, we performed RNA sequencing on ERα-positive breast cancer cell lines (MCF-7 and T-47D) following treatment with the selective estrogen receptor degrader fulvestrant and/or exposure to hypoxic conditions (1% O₂). Cells were cultured for 96 hours in the presence or absence of 100 nM fulvestrant, with the final 48 hours spent under normoxia or hypoxia. RNA was extracted from biological triplicates and sequenced using Illumina short-read technology (≥20 million reads/sample). Differential gene expression analysis revealed distinct transcriptional programmes regulated by ERα and hypoxia, as well as a large set of overlapping genes modulated by both conditions. Fulvestrant-induced ERα degradation suppressed canonical estrogen-responsive genes (e.g. GREB1, TFF1) and upregulated EPAS1 (HIF-2α). Hypoxia induced well-characterised HIF targets (e.g. CA9, VEGFA).
2025-07-21 | E-MTAB-15331 | biostudies-arrayexpress
Project description:Oral selective estrogen receptor degraders (SERDs) could become the backbone endocrine therapy (ET) for estrogen receptor-positive (ER+) breast cancer, as they achieve greater inhibition of ER-driven cancers than current ETs and overcome key resistance mechanisms. This dataset was aimed at exploring the preclinical effects of the next-generation oral SERD camizestrant (AZD9833) on MCF7 and CAMA1 cell lines. Cells were treated with 1 nM estradiol and 100 nM fulvestrant, AZD9496, or camizestrant for 24 hours, with three replicates per condition and non-estradiol-treated controls.
2023-09-11 | E-MTAB-13113 | biostudies-arrayexpress
Project description:Multiple gene expression studies have demonstrated that breast cancer biological diversity is associated with distinct transcriptional programs. Transcription factors, because of their unique ability to coordinate the expression of multiple genes, are speculated to play a role in generating phenotypic plasticity associated with cancer progression including acquired drug resistance. Combinatorial libraries of artificial zinc-finger transcription factors (ZF-TFs) provide a robust means for inducing and understanding various functional components of the cancer phenotype. Herein, we utilized combinatorial ZF-TF library technology to better understand how breast cancer cells acquire resistance to a fulvestrant, a clinically important anti-endocrine therapeutic agent. We isolated six ZF-TF library members capable of inducing stable, long-term anti-endocrine drug-resistance in two independent estrogen receptor positive breast cancer cell lines. Comparative gene expression profile analysis of the ZF-TF-transduced breast cancer cell lines revealed a 72-gene cluster that constituted a common signature for the fulvestrant-resistance phenotype. Pathway enrichment-analysis of gene expression data revealed that the ZF-TF-induced fulvestrant resistance is associated with an estrogen receptor negative-like gene set and four unique myb-regulated gene sets. Furthermore, we identified a set of genes strongly expressed in the ZF-TF-induced fulvestrant-resistant cells that was correlated with a lower probability of distant metastasis-free or death-from-relapse-free survival of breast cancer patients.
2011-07-18 | GSE27444 | GEO
Project description:To investigate molecular mechanisms of resistance, we used two different in vivo xenograft models of estrogen receptor-positive (ER+) breast cancer, with or without HER2 over-expression (MCF7/HER2-18 and MCF7 wt, respectively). Mice with established tumors were assigned to the following treatment groups: continued estrogen supplementation (E2), estrogen deprivation (ED), ED plus tamoxifen (Tam), all with or without the EGFR tyrosine kinase inhibitor gefinitinib (G). Another group received ED plus the antiestrogen fulvestrant (MCF7 wt only). Tumors with acquired or de novo resistance to these endocrine therapies were profiled for mRNA expression using Affymetrix Genechip arrays. This SuperSeries is composed of the SubSeries listed below.
2008-12-01 | GSE8141 | GEO
Project description:To investigate molecular mechanisms of resistance, we used two different in vivo xenograft models of estrogen receptor-positive (ER+) breast cancer, with or without HER2 over-expression (MCF7/HER2-18 and MCF7 wt, respectively). Mice with established tumors were assigned to the following treatment groups: continued estrogen supplementation (E2), estrogen deprivation (ED), ED plus tamoxifen (Tam), all with or without the EGFR tyrosine kinase inhibitor gefinitinib (G). Another group received ED plus the antiestrogen fulvestrant (MCF7 wt only). Tumors with acquired or de novo resistance to these endocrine therapies were profiled for mRNA expression using Affymetrix Genechip arrays. Keywords: multiple group comparison
2008-12-01 | GSE8140 | GEO
Project description:To investigate molecular mechanisms of resistance, we used two different in vivo xenograft models of estrogen receptor-positive (ER+) breast cancer, with or without HER2 over-expression (MCF7/HER2-18 and MCF7 wt, respectively). Mice with established tumors were assigned to the following treatment groups: continued estrogen supplementation (E2), estrogen deprivation (ED), ED plus tamoxifen (Tam), all with or without the EGFR tyrosine kinase inhibitor gefinitinib (G). Another group received ED plus the antiestrogen fulvestrant (MCF7 wt only). Tumors with acquired or de novo resistance to these endocrine therapies were profiled for mRNA expression using Affymetrix Genechip arrays. Keywords: multiple group comparison
2008-12-01 | GSE8139 | GEO
Project description:Estrogens have been shown to elicit anti-cancer effects against estrogen receptor alpha (ER)-positive breast cancer. We sought to determine the underlying mechanism of therapeutic response. Response to 17b-estradiol was assessed in ER+ breast cancer models with resistance to estrogen deprivation: WHIM16 patient-derived xenografts, C7-2-HI and C4-HI murine mammary adenocarcinomas, and long-term estrogen-deprived MCF-7 cells. As another means to reactivate ER, the anti-estrogen fulvestrant was withdrawn from fulvestrant-resistant MCF-7 cells. Transcriptional, growth, apoptosis, and molecular alterations in response to ER reactivation were measured. 17b-estradiol treatment and fulvestrant withdrawal induced transcriptional activation of ER, and cells adapted to estrogen deprivation or fulvestrant were hypersensitive to 17b-estradiol. ER transcriptional response was followed by an unfolded protein response and apoptosis. Such apoptosis was dependent upon the unfolded protein response, p53, and JNK signaling. Anti-cancer effects were most evident in models exhibiting genomic amplification of the gene encoding ER (ESR1), suggesting that engagement of ER at high levels is cytotoxic. These data indicate that long-term adaptation to estrogen deprivation or ER inhibition alters sensitivity to ER reactivation. In such adapted cells, 17b-estradiol treatment and anti-estrogen withdrawal hyperactivate ER, which drives an unfolded protein response activation and subsequent growth inhibition and apoptosis. 17b-estradiol treatment should be considered as an alternative therapy for anti-estrogen-resistant disease, particularly in patients with tumors harboring ESR1 amplification or overexpression. Furthermore, therapeutic strategies that enhance an unfolded protein response may enhance the therapeutic effects of ER reactivation.
2019-08-19 | GSE121379 | GEO
Project description:To investigate molecular mechanisms of resistance, we used two different in vivo xenograft models of estrogen receptor-positive (ER+) breast cancer, with or without HER2 over-expression (MCF7/HER2-18 and MCF7 wt, respectively). Mice with established tumors were assigned to the following treatment groups: continued estrogen supplementation (E2), estrogen deprivation (ED), ED plus tamoxifen (Tam), all with or without the EGFR tyrosine kinase inhibitor gefinitinib (G). Another group received ED plus the antiestrogen fulvestrant (MCF7 wt only). Tumors with acquired or de novo resistance to these endocrine therapies were profiled for mRNA expression using Affymetrix Genechip arrays. This SuperSeries is composed of the following subset Series:; GSE8139: Expression data from MCF7/HER2-18 xenografts; GSE8140: Expression data from MCF7 wt xenografts Experiment Overall Design: MCF7 xenografts were established in ovariectomized five to six week-old nu/nu athymic nude mice supplemented with 0.25 mg 21 day release estrogen pellets by inoculating subcutaneously (s.c.) 5E-6 cells. When tumors reached the size of 150-200 mm3 (3-5 weeks), the animals were randomly allocated to continued estrogen (E2), continued estrogen with gefitinib (E2+G; 100mg/kg, 5 days/week), estrogen withdrawal alone (ED; by removal of the estrogen pellets), and estrogen withdrawal plus tamoxifen citrate (Tam; 500 microg/animal s.c. in peanut oil, 5 days/week), with either gefitinib (Tam+G; 100mg/kg, 5 days/week) or vehicle (1% Tween 80) administered via gavage, as well as estrogen withdrawal plus fulvestrant (ICI 182,780) in the MCF7 wt model (Fulv; 5mg/mouse s.c. once weekly), and estrogen withdrawal with gefitinib (ED+G). Tumors were harvested for molecular studies when they became resistant to treatment and reached the size of 1000 mm3 (n=7). Experiment Overall Design: Refer to individual Series
2008-12-05 | E-GEOD-8141 | biostudies-arrayexpress
Project description:Full title: Expression data from antisense miRNA-221/222 (si221/222) and control inhibitor (GFP) treated fulvestrant-resistant breast cancer cells The expression of miR-221/222 were found to be upregulated in fulvestrant resistant breast cancer cells MCF7-FR compared to its drug-sensitive counterpart MCF7. To investigate the role of miR-221/222 in acquired resistance to fulvestrant, we lowered the level of miR-221/222 in MCF7-FR cells using miRNA inhibitors (antagomirs), and compared gene expression profiles before and after treatment. Fulvestrant-resistant breast cancer cells MCF7-FR (originated from drug-sentitive breast cancer model cell line MCF7) were transient-transfected by antigomirs targeting miR221 or miR222 (i.e. si221, si222). All three cell lines, MCF7-FR, siR221, siRNA222 were subjected to gene expression profiling.
2011-01-29 | E-GEOD-19777 | biostudies-arrayexpress