Mus musculus
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ABSTRACT:
PROVIDER: PRJNA269273 | ENA |
REPOSITORIES: ENA
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Project description:The overarching goal of this study was to explore the antitumor activity of Z-endoxifen, a tamoxifen metabolite, with first-line endocrine therapies tamoxifen and letrozole in the letrozole-sensitive MCF7 aromatase expressing model (MCF7AC1), and with second-line endocrine therapies including tamoxifen, fulvestrant, exemestane, and exemestane plus everolimus, in letrozole-resistant MCF7 model (MCF7LR) in vivo. We used microarray to identify genes that are commonly and differently reguated by Z-endoxifen and tamoxifen treatments in the letrozole-resistant MCF7LR tumors.
2020-03-13 | GSE146911 | GEO
Project description:To investigate response or resistance to endocrine therapy, mice with targeted over-expression of Esr1 or CYP19A1 to mammary epithelial cells were employed, representing two direct pathophysiological interventions in estrogen pathway signaling. Both Esr1 and CYP19A1 over-expressing mice responded to letrozole with reduced HAN prevalence and decreased mammary epithelial cell proliferation. CYP19A1 over-expressing mice were tamoxifen-sensitive but Esr1 over-expressing mice were tamoxifen-resistant. Increased ER expression occurred with tamoxifen resistance but no consistent changes in progesterone receptor, pSTAT3, pSTAT5, cyclin D1 or cyclin E levels in association with response or resistance was found. RNA-seq was employed to seek a transcriptome predictive of tamoxifen resistance using these models and a second tamoxifen-resistant model, BRCA1 deficient/Trp53 haploinsufficient mice. Sixty-eight genes associated with immune system processing were upregulated in tamoxifen-resistant Esr1 and Brca1 deficient mice whereas genes related to aromatic compound metabolic process were upregulated in tamoxifen-sensitive CYP19A1 mice. Interferon Regulatory Factor 7 was identified as a key transcription factor regulating these 68 immune processing genes. Two loci encoding novel transcripts with high homology to human IGLL1 were uniquely upregulated in the tamoxifen-resistant models. Letrozole proved to be a successful alternative to tamoxifen. Further study of transcriptional changes associated with tamoxifen resistance including immune-related genes could expand our mechanistic understanding and lead to biomarkers predictive of escape or response to endocrine therapies. Single- and paired-end mRNA-seq with WT, Esr1 over-expressing (CERM, tetracycline-operator(tet-op)-Esr1MMTV-rtTA), CYP19A1 over-expressing (AROM, tet-op-CYP19A1MMTV-rtTA) and Brca1 KO (BRCA, Brca1fl11/fl11/MMTV-Cre/p53+/- ) mice
2014-12-04 | E-GEOD-63857 | biostudies-arrayexpress
Project description:To investigate response or resistance to endocrine therapy, mice with targeted over-expression of Esr1 or CYP19A1 to mammary epithelial cells were employed, representing two direct pathophysiological interventions in estrogen pathway signaling. Both Esr1 and CYP19A1 over-expressing mice responded to letrozole with reduced HAN prevalence and decreased mammary epithelial cell proliferation. CYP19A1 over-expressing mice were tamoxifen-sensitive but Esr1 over-expressing mice were tamoxifen-resistant. Increased ER expression occurred with tamoxifen resistance but no consistent changes in progesterone receptor, pSTAT3, pSTAT5, cyclin D1 or cyclin E levels in association with response or resistance was found. RNA-seq was employed to seek a transcriptome predictive of tamoxifen resistance using these models and a second tamoxifen-resistant model, BRCA1 deficient/Trp53 haploinsufficient mice. Sixty-eight genes associated with immune system processing were upregulated in tamoxifen-resistant Esr1 and Brca1 deficient mice whereas genes related to aromatic compound metabolic process were upregulated in tamoxifen-sensitive CYP19A1 mice. Interferon Regulatory Factor 7 was identified as a key transcription factor regulating these 68 immune processing genes. Two loci encoding novel transcripts with high homology to human IGLL1 were uniquely upregulated in the tamoxifen-resistant models. Letrozole proved to be a successful alternative to tamoxifen. Further study of transcriptional changes associated with tamoxifen resistance including immune-related genes could expand our mechanistic understanding and lead to biomarkers predictive of escape or response to endocrine therapies.
2014-12-04 | GSE63857 | 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: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:Reproductive senescence is an age-associated process in which reproductive capacity is reduced. In female mice this is associated with loss of oocytes and a corresponding reduction in ovarian estrogen production. Normal mammary gland development and function is linked to estrogen stimulation. In this study we utilize two genetically engineered mouse models of breast cancer risk, one with mammary-targeted conditional expression of Esr1, the RNA that encodes Estrogen Receptor alpha, and one with mammary-targeted conditional expression of CYP19A1, the RNA that encodes Aromatase, the enzyme that is responsible for estrogen synthesis from androgens to determine how reproductive senescence impacts the transcriptional response to commonly used anti-hormonals employed for breast cancer prevention, tamoxifen and letrozole. The goals of the study are, first, to test the extent to which each of these anti-hormonals alter the mammary gland transcriptome in mice undergoing reproductive senescence and, second, determine if the response is the same or different in the presence of Esr1 as compared to CYP19A1 transgene expression targeted to mammary epithelial cells. The objectives are to identify specific genes that are significantly differentially expressed genes within each model between treatment conditions control, tamoxifen and letrozole as well as between models under each of these conditions. Transcriptome comparisons between 18- and 20-month-old mice are used to identify differences between the two models as ovarian function diminishes during reproductive senescence. Transcriptome comparisons between cohorts of 20-month-old mice that received no anti-hormonal or a two-month-exposure to tamoxifen or letrozole beginning at age 18 months are used to identify similarities and differences between the two anti-hormonal treatments as well as similarities and differences between models.
2022-08-07 | GSE201326 | GEO
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: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: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.
2007-10-27 | E-GEOD-2225 | biostudies-arrayexpress
Project description:Acquired resistance to aromatase inhibitor (AI) therapy is a major clinical problem in the treatment of breast cancer. The detailed mechanisms of how tumour cells develop this resistance remain unclear. Here estrogen receptor ChIPseq analysis identifies adaptations of the ER in response to prolonged letrozole treatment.
2016-03-21 | GSE54592 | GEO