Genome-wide copy number profiling of MCF-7 and fulvestrant-resistant MCF-7/FR cells by SNP microarray.
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PROVIDER: PRJNA497897 | ENA |
REPOSITORIES: ENA
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Project description:Fulvestrant withdrawal from fulvestrant-resistant MCF-7/FR cells
| PRJNA497213 | ENA
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 As another means to reactivate ER, the anti-estrogen fulvestrant was withdrawn from fulvestrant-resistant MCF-7 cells.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 | GSE121631 | 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 generate a dormancy state in vivo, ovariectomized female BALB/c athymic mice (simulating the post-menopausal state) with ER+MC cell (MCF7) derived xenografts were treated with Fulvestrant (FUL). Throughout the treatment period, no significant differences in the body weight of the FUL-treated groups (FD and FR) compared to the vehicle-treated groups (FC) were observed. Whereas xenografts in the vehicle-treated group (as control group: FC) continued to increase in volume, the xenograft volumes of the FUL-treated group regressed 20%-30% in the first week and then remained stable during the four-week administration of FUL. Thereafter, half of the xenografts in FUL-treated mice were resected at random and designated as a dormancy-like group (FD). For the remaining FUL treated xenografts, treatment was discontinued and xenograft volume was observed to gradually increase. This group was defined as the relapse group (FR) and would mimic relapses observed after discontinuation of anti-estrogen therapy in patients.
2024-11-08 | GSE280970 | GEO
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
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.
2011-01-29 | GSE19777 | GEO
Project description:High levels of Tissue Inhibitor of Metalloproteinases-1 (TIMP1) are associated with poor prognosis, reduced response to chemotherapy, and, potentially, also poor response to endocrine therapy in breast cancer patients. Our objective was to further investigate the hypothesis that TIMP1 is associated with endocrine sensitivity. We established a panel of 11 MCF-7 subclones with a wide range of TIMP1 mRNA and protein expression levels. Cells with high expression of TIMP1 versus low TIMP1 displayed significantly reduced sensitivity to the antiestrogen fulvestrant (ICI 182,780, Faslodex®), while TIMP1 levels did not influence the sensitivity to 4-hydroxytamoxifen. An inverse correlation between expression of the progesterone receptor and TIMP1 was found, but TIMP1 levels did not correlate with estrogen receptor levels or growth-promoting effects of estrogen (estradiol, E2). Additionally, the effects of fulvestrant, 4-hydroxytamoxifen, or estrogen on estrogen receptor expression were not associated with TIMP1 levels. Gene expression analyses revealed associations between expression of TIMP1 and genes involved in metabolic pathways, epidermal growth factor receptor 1/cancer signaling pathways, and cell cycle. Gene and protein expression analyses showed no general defects in estrogen receptor signaling except from lack of progesterone receptor expression and estrogen inducibility in clones with high TIMP1. The present study suggests a relation between high expression level of TIMP1 and loss of progesterone receptor expression combined with fulvestrant resistance. Our findings in vitro may have clinical implications as the data suggest that high tumor levels of TIMP1 may be a predictive biomarker for reduced response to fulvestrant. Microarray analysis of total RNA from 10 subclones of MCF-7 breast cancer cells with various expression levels of TIMP1.
2013-08-22 | E-GEOD-35535 | biostudies-arrayexpress
Project description:We treated steroid-deprived MCF7 cells with DMSO (Vehicle), 1 nM 17b-estradiol (E2), 100 nM fulvestrant (Fulv), or a combination of fulvestrant and estradiol for 24 hours
2024-06-05 | GSE231397 | GEO
Project description:Gene expression of Fulvestrant induced control (FC), dormancy-like (FD) or relapse (FR) cell samples
| PRJNA1181568 | ENA
Project description:High levels of Tissue Inhibitor of Metalloproteinases-1 (TIMP1) are associated with poor prognosis, reduced response to chemotherapy, and, potentially, also poor response to endocrine therapy in breast cancer patients. Our objective was to further investigate the hypothesis that TIMP1 is associated with endocrine sensitivity. We established a panel of 11 MCF-7 subclones with a wide range of TIMP1 mRNA and protein expression levels. Cells with high expression of TIMP1 versus low TIMP1 displayed significantly reduced sensitivity to the antiestrogen fulvestrant (ICI 182,780, Faslodex®), while TIMP1 levels did not influence the sensitivity to 4-hydroxytamoxifen. An inverse correlation between expression of the progesterone receptor and TIMP1 was found, but TIMP1 levels did not correlate with estrogen receptor levels or growth-promoting effects of estrogen (estradiol, E2). Additionally, the effects of fulvestrant, 4-hydroxytamoxifen, or estrogen on estrogen receptor expression were not associated with TIMP1 levels. Gene expression analyses revealed associations between expression of TIMP1 and genes involved in metabolic pathways, epidermal growth factor receptor 1/cancer signaling pathways, and cell cycle. Gene and protein expression analyses showed no general defects in estrogen receptor signaling except from lack of progesterone receptor expression and estrogen inducibility in clones with high TIMP1. The present study suggests a relation between high expression level of TIMP1 and loss of progesterone receptor expression combined with fulvestrant resistance. Our findings in vitro may have clinical implications as the data suggest that high tumor levels of TIMP1 may be a predictive biomarker for reduced response to fulvestrant.
2013-08-22 | GSE35535 | GEO