ABSTRACT: TIMP1 overexpression mediates resistance of MCF-7 human breast cancer cells to fulvestrant and down-regulates progesterone receptor expression
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.
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.
Project description:A significant fraction of breast cancers exhibit de novo or acquired resistance to estrogen deprivation. To model resistance to aromatase inhibitor (AI) therapy, long-term estrogen-deprived (LTED) derivatives of MCF-7 and HCC-1428 cells were generated through culture for 3 and 7 months under hormone-depleted conditions, respectively. These LTED cells showed sensitivity to the ER downregulator fulvestrant under hormone-depleted conditions, suggesting continued dependence upon ER signaling for hormone-independent growth. To evaluate the role of ER in hormone-independent growth, LTED cells were treated +/- 1 uM fulvestrant x 48 h before RNA was harvested for gene expression analysis. MCF-7/LTED and HCC-1428/LTED cells were treated with 10% DCC-FBS with or without the estrogen receptor antagonist drug fulvestrant for 48 hrs prior to RNA harvest for array analysis. Three replicates per condition.
Project description:Goal: study the impact of estrogen receptor (ER) ligands on ER binding to chromatin in MCF-7 cells Methods: ER Chromatin Immunoprecipitation and Sequencing (ChIP-seq) Results: All tested ligands increase binding of ER onto DNA in MCF-7 breast cells. These ligands thus promote an association between ER and DNA, irrespective of their mode of action: selective ER modulator (SERM) 4-OH tamoxifen, and selective ER degraders (SERD) fulvestrant and GDC-0927.
Project description:Goal: study the impact of estrogen receptor ligands on chromatin accessibility in MCF-7 cells Methods: Assay for Transposase-Accessible Chromatin using Sequencing (ATAC-Seq) Results: Ligand 4-OH tamoxifen, a selective ER modulator (SERM), significantly alters chromatin accessibility and partially mimics the effect of natural ligand E2 on chromatin accessibility in MCF-7 breast cells. Selective ER degraders (SERD) fulvestrant and GDC-0927 on the other hand have very little impact on chromatin accessibility.
Project description:Analysis of tumor suppression by cell cycle-related genes which are regulated by SCTR(Secretin receptor) at gene expression level. The hypothesis tested in the present study was that SCTR regulates cell cycle-related genes toward tumor suppression in normal breast cells. Results suggest that normal breast cells have tumor suppressor activity when SCTR was knocked down by siRNA. Total RNA obtained from MCF-10A where SCTR was knocked down by siRNA
Project description:Transducin-like enhancer protein 1 mediates estrogen receptor binding and transcriptional activity in breast cancer cells TLE1 silenced breast cancer MCF-7 cell lines or control siRNA in the presence of Estrogen or a vehicle. MCF-7 cells were hormone-depleted for 3 d and treated with 100 nM estrogen (or vehicle) for 6 h. There were six biological replicates for each of the four different groups.
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.
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.
Project description:Analysis of MCF-7 cells following miR-9 stable overexpression or not. MiR-9 regulates various mRNA expression in MCF-7 cells.Results provide insight into the role of miR-9-involved mechanisms underlying miR-9-mediated effects on breast cancer stemness.