Identification of miRNA differential expression patterns in a new model of acquired letrozole resistance
Ontology highlight
ABSTRACT:
ORGANISM(S): synthetic construct Homo sapiens
PROVIDER: GSE43766 | GEO | 2013/01/30
SECONDARY ACCESSION(S): PRJNA187554
REPOSITORIES: GEO
Similar Datasets
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: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. Experiment Overall Design: For control purposes, MCF-7aro cells were cultured without any hormone or inhibitor as well as a hormone-only control (T-only). Resistant cells were grown in the presence of testosterone, T+LET R (letrozole), T+ANA R (anastrozole), T+EXE R (exemestane), T+TAM R (Tamoxifen). In addition, testosterone-free resistant lines were generated, LTEDaro, ANA R and EXE R. 6 replicates were generated for the hormone-containing resistant lines and 3 replicates for the hormone-free resistant lines.
2008-04-04 | E-GEOD-10911 | 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
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:Background: AZD4547 is a potent and selective inhibitor of FGFR-1, 2 and 3 receptor tyrosine kinases. Phase 1 studies both in Europe and Japan have shown that the compound is well tolerated and shows activity in patients with solid tumours. Here, we hypothesised that AZD4547 could reverse resistance to AIs such as anastrozole and letrozole. Methods: After a safety run-in study in which 6 patients had PK and safety assessments on combined AI plus AZD4547, we recruited 52 eligible patients with metastatic breast cancer who had progressed on treatment with anastrozole or letrozole. The primary objective of the phase lla study was to assess the efficacy of AZD4547 based on the change in tumour size when used in combination with either anastrozole or letrozole in ER positive breast cancer patients who have progressed on treatment with either anastrozole or letrozole in any setting. Results:. According to centrally reviewed RECIST criteria, five partial response (PR) and 8 stable disease (SD) patients were observed from a total of 50 assessable cases, giving a Clinical Benefit Rate (PR + SD) of 26% (95% CI: 14.6-40.3%). RNA-Seq was done on a subset of patients’ samples: 6 differentially-expressed-genes could distinguish those who benefited from the addition of AZD4547. Eleven patients had retinal pigment epithelial detachments (RPEDs) either in one or both eyes which was asymptomatic and reversible, although RPED recurred in one patient on re-treatment. Twenty six (50%) and 7(13%) patients had elevated phosphate and calcium, respectively. Conclusions: in a group of unselected ER positive women with aromatase inhibitor-resistant metastatic breast cancer, FGFR pathway inhibition combined with letrozole or anastrozole provided clinical benefit in a significant proportion of patients with manageable toxicity.
2022-03-18 | GSE198650 | 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:Biopsies were collected from post-menopausal women with ER+ HER2- breast cancer who were subsequently treated with either letrozole or letrozole plus bevacizumab.
2019-12-19 | GSE142308 | GEO
Project description:Obesity represents a risk factor for breast cancer development and therapy resistance, but the molecular players underling these links are unclear. Here, we identify a role for the obesity-cytokine leptin in sustaining aromatase inhibitor (AI) resistant growth and progression in breast cancer. Using as a cellular model MCF-7 breast cancer cells surviving long-term to the AI treatment Anastrozole (AnaR) and Ana-sensitive counterparts, we found that AnaR cells expressed higher levels of leptin and its receptors (ObR) along with a constitutive activation of downstream effectors. Accordingly, leptin signaling inhibition reduced only AnaR cell growth and motility, highlighting the existence of an autocrine loop in mechanisms governing drug-resistant phenotype. In agreement with ObR overexpression, increasing doses of leptin were able to stimulate at a greater extent growth and migration in AnaR than sensitive cells. Moreover, leptin contributed to an enhanced crosstalk between AnaR cells and macrophages within tumor microenvironment. Indeed, AnaR through leptin secretion modulated macrophage profiles and increased macrophage motility through CXCR4 signaling, as evidenced by RNA-sequencing, realtime-PCR and immunoblotting. Reciprocally, activated macrophages increased AnaR cell growth and motility in coculture systems.
2022-03-04 | E-MTAB-8843 | biostudies-arrayexpress
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