ER ChIP-seq of Androstenedione treated Letrozole Resistant Breast Cancer Cell line
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE54592 | GEO | 2016/03/21
SECONDARY ACCESSION(S): PRJNA237102
REPOSITORIES: GEO
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Project description:Since differential miRNA expression patterns associated with acquired AI resistance have been poorly investigated, the aim of this study was to delineate the deregulation of miRNA expression associated with aromatase inhibitor (AI) response failure in new cellular models of AI resistance. For this purpose, we generated and characterized novel cellular models of acquired resistance to letrozole (Res-Let cells) and to anastrozole (Res-Ana cells) and performed microarray experiments to identify miRNAs whose expression was either deregulated between control (MCF-7aro) and resistant cells (Res-Let or Res-Ana). With the aim to select relevant miRNAs, two independent cell culture replicates were performed for each experimental condition.
2013-01-30 | GSE43766 | GEO
Project description:Resistance to endocrine therapy agents has presented a clinical obstacle in the treatment of hormone-dependent breast cancer. Our laboratory has initiated a study of microRNA regulation of signaling pathways that may result in breast cancer progression on aromatase inhibitors (AI). Microarray analysis of microRNA expression identified 115 significantly regulated microRNAs, of which 49 microRNAs were believed to be hormone-responsive. Within the AI-resistant cells, microRNAs were differentially expressed between the steroidal and non-steroidal AI-resistant lines. Also, a group of microRNAs were inversely expressed in the AI-resistant lines versus LTEDaro and tamoxifen-resistant. We focused our work on hsa-miR-128a which was hormone-responsive and up-regulated in the letrozole-resistant cell lines. Human miR-128a was shown to negatively target TGFBRI protein expression by binding to the 3âUTR region of the gene. Loss of TGFBRI resulted in compromised sensitivity to the growth inhibitory effects of TGFB in the letrozole-resistant lines. Inhibition of endogenous miR-128a resulted in re-sensitization of the letrozole-resistant lines to TGFB growth inhibitory effects. This data suggests that the hormone-responsive miR-128a can modulate TGFB signaling and survival of the letrozole-resistant cell lines. To our knowledge, this is the first study to address the role of microRNA regulation as well as TGFB signaling in AI-resistant breast cancer cell lines. We believe that in addition to estrogen-modulation of gene expression, hormone-regulated microRNAs may provide an additional level of post-transcriptional regulation of signaling pathways critically involved in breast cancer progression and AI-resistance. To look at microRNA expression profiles of breast cancer cell lines derived from MCF-7 cells that are resistant to endocrine therapy agents. MCF-7 cells that overexpress aromatase (MCF-7aro) were cultured long-term in the presence of endocrine therapy agents until cells acquired resistance. Three different aromatase inhibitors (letrozole, anastrozole or exemestane) were used, as well as the ER antagonist tamoxifen, or the hormone-free long-term estrogen deprived cells (LTED). Three replicates of the control cells (MCF-7aro) and all resistant cells were used for microarray experiments. Total of 23 samples were analyzed by microarray.
2010-05-16 | E-GEOD-17775 | biostudies-arrayexpress
Project description:MCF-7aro cells were used to generate a cell culture model system that is resistant to 3 aromatase inhibitors (AIs), letrozole, anastrozole and exemestane. For comparison, the MCF-7aro cells were also used to generate the tamoxifen-resistant cells as well as long-term estrogen deprived, LTEDaro. Affymetrix microarray analysis was performed to determine changes in gene expression that are unique to AI-resistance. Keywords: cell lines, aromatase inhibitor resistance, tamoxifen resistance
2008-03-22 | GSE10911 | GEO
Project description:Anti-estrogens and aromatase inhibitors are important drugs in the treatment of estrogen-dependent breast cancer. In order to investigate the effects of these drugs on gene expression in breast cancer cells, we treated estrogen receptor-positive MCF-7 cells, stably transfected with the aromatase gene (known as MCF-7aro cells), with testosterone, 17β-estradiol, two aromatase inhibitors (letrozole and anastrozole), and an anti-estrogen (tamoxifen). Microarray analyses using Affymetrix Human Genome U133A GeneChips were carried out using total RNA isolated from the control and treated cells. When comparing the effect of each inhibitor on gene expression we observe that letrozole and anastrozole are more similar in terms of the genes they affect, compared to treatment with tamoxifen. The results of this study provide us with a better understanding of the actions of both aromatase inhibitors and anti-estrogens at the molecular level. We believe that the results of this study serve as the first step in identifying unique expression patterns following drug treatment, and that this will ultimately be useful in customizing patient treatment strategies for estrogen-dependent breast cancer. The data presented here have been processed using the R-Project Bioconductor statistical tools package using the affy library. The following were applied: RMA background correction, pmonly probe-level correction, quantile normalization, avgdiff summary method. Raw data is provided in the form of .CEL files. Keywords = estrogen-dependent breast cancer Keywords = aromatase Keywords: other
2006-02-02 | GSE2225 | GEO
Project description:Since differential miRNA expression patterns associated with acquired AI resistance have been poorly investigated, the aim of this study was to delineate the deregulation of miRNA expression associated with letrozole response failure in a new model of letrozole resistance. For this purpose, we generated and characterized a novel cellular model of acquired resistance to letrozole (Res-Let cells) and performed microarray experiments to identify miRNAs whose expression was either deregulated between control (MCF-7aro) and resistant cells (Res-Let) or differentially expressed between the two cell lines under letrozole exposure. With the aim to select relevant miRNAs, two independent cell culture replicates were performed for each experimental condition. MCF-7aro and Res-Let cells were grown in the presence of androstenedione (AD) combined or not with letrozole. Two independent cell culture replicates for each experimental condition were used to generate total RNA. Total RNA was extracted from cell culture using a Qiagen RNA extraction kit and RNA quality was assessed using the BioAnalyzer 2100M-bM-^DM-" (Agilent Technologies). Complex probes were produced from these RNA, then hybridized to GeneChipM-BM-. miRNA 3.0 array according to the manufacturer's recommendations (Affymetrix).
2013-01-30 | E-GEOD-43766 | biostudies-arrayexpress
Project description:Endocrine therapy reduces breast cancer mortality by 40%; but resistance remains a major clinical problem. Identification of gene signatures associated with resistance during endocrine treatment should enable rational therapeutic choices to be made to combat this in individual patients. Here we present an in-depth analysis of global gene-expression that was measured on pairs of core-cut biopsies taken at baseline and at surgery from 254 patients with ER-positive primary breast cancer randomised to receive 2-week’s presurgical AI (n=198) or no presurgical treatment (Control n=56) in the POETIC trial, using changes-in and residual-of the proliferation marker, Ki67 as end-points, to investigate the impact of aromatase inhibitor (AI) therapy on gene expression and identify gene modules representing key biological pathways that relate to early AI-therapy resistance. Our study revealed a high degree of heterogeneity in adaptive mechanisms after as little as 2-weeks’ AI-therapy, however, all appear to converge on cell cycle regulation. Our data support the evaluation of whether an E2F signatures after short-term exposure to AI may identify those patients most likely to benefit from the early addition of CDK4/6 inhibitors.
2020-02-24 | GSE126870 | GEO
Project description:Resistance to endocrine therapy agents has presented a clinical obstacle in the treatment of hormone-dependent breast cancer. Our laboratory has initiated a study of microRNA regulation of signaling pathways that may result in breast cancer progression on aromatase inhibitors (AI). Microarray analysis of microRNA expression identified 115 significantly regulated microRNAs, of which 49 microRNAs were believed to be hormone-responsive. Within the AI-resistant cells, microRNAs were differentially expressed between the steroidal and non-steroidal AI-resistant lines. Also, a group of microRNAs were inversely expressed in the AI-resistant lines versus LTEDaro and tamoxifen-resistant. We focused our work on hsa-miR-128a which was hormone-responsive and up-regulated in the letrozole-resistant cell lines. Human miR-128a was shown to negatively target TGFBRI protein expression by binding to the 3’UTR region of the gene. Loss of TGFBRI resulted in compromised sensitivity to the growth inhibitory effects of TGFB in the letrozole-resistant lines. Inhibition of endogenous miR-128a resulted in re-sensitization of the letrozole-resistant lines to TGFB growth inhibitory effects. This data suggests that the hormone-responsive miR-128a can modulate TGFB signaling and survival of the letrozole-resistant cell lines. To our knowledge, this is the first study to address the role of microRNA regulation as well as TGFB signaling in AI-resistant breast cancer cell lines. We believe that in addition to estrogen-modulation of gene expression, hormone-regulated microRNAs may provide an additional level of post-transcriptional regulation of signaling pathways critically involved in breast cancer progression and AI-resistance.
2010-01-01 | GSE17775 | GEO
Project description:breast cancer. Combined IGF and estrogen-targeted therapy may improve the benefit of hormonal therapy alone. We employed a postmenopausal model of estrogen-dependent breast cancer in vitro and in vivo using the aromatase-expressing MCF-7/AC-1cells. Using this model, we investigated the anti-tumor effects of the dual IGF-1R/InsR tyrosine kinase inhibitor, BMS-754807 alone and in combination with letrozole or tamoxifen in vivo. We used microarrays to compare gene expression changes of MCF7 breast xenograft treated with either BMS754807, or Tamoxifen or Letrozole alone; or Tamoxifen or Letrozole in combination with BMS754807 for 28 days
2011-11-02 | GSE33366 | GEO
Project description:breast cancer. Combined IGF and estrogen-targeted therapy may improve the benefit of hormonal therapy alone. We employed a postmenopausal model of estrogen-dependent breast cancer in vitro and in vivo using the aromatase-expressing MCF-7/AC-1cells. Using this model, we investigated the anti-tumor effects of the dual IGF-1R/InsR tyrosine kinase inhibitor, BMS-754807 alone and in combination with letrozole or tamoxifen in vivo. We used microarrays to compare gene expression changes of MCF7 breast xenograft treated with either BMS754807, or Tamoxifen or Letrozole alone; or Tamoxifen or Letrozole in combination with BMS754807 for 28 days Breast xenograft MCF7 bearing mice treated with either BMS754807, or Tamoxifen or Letrozole alone; or Tamoxifen or Letrozole in combination with BMS754807 for 28 days. RNA were extracted from tumors and hybridizedon Affymetrix microarrays to compare gene expression changes
2011-11-02 | E-GEOD-33366 | biostudies-arrayexpress
Project description:<p>These are tumor biopsies and corresponding normal samples from patients with early stage ER+/HER2- breast cancer who had received the aromatase inhibitor letrozole for 10-21 days prior to surgery.</p>
| phs000857 | dbGaP