Project description:Compare the expression pattern of 17b-estradiol responsive genes in parent, OHT-resistant and ICI-resistant breast cancer cells. Keywords: 17b-estradiol responsive genes, OHT resistance, Fulvestrand resistance
Project description:MCF7 breast cancer cell lines: drug-resistant (OHT and ICI) cell lines vs. drug-sensitive (wild type) cell lines. Assessment of association between gene expression and methylation. Two comparisons: OHT-resistant vs. wild type, and ICI-resistant vs. wild type. OHT: 4-hydroxytamoxifen ICI: fulvestrant ((ICI 182780) This submission represents the methylation component of the study.
Project description:MCF7 breast cancer cell lines: drug-resistant (OHT and ICI) cell lines vs. drug-sensitive (wild type) cell lines. Assessment of association between gene expression and methylation.
Project description:RNA-seq: Gene expression profiling in MCF-7 cells treated with vehicle (0), estradiol (E2), the Selective ER Modulator 4-hydroxytamoxifen (OHT), or the pure antiestrogen fulvestrant (ICI). ChIP-seq: Genome-wide DNA binding profile of ERα and SUMO2/3 in MCF-7 cells treated with vehicle, E2 or ICI.
Project description:Estrogen receptor positive (ER+) breast cancer is the most common type of breast cancer. Despite the great efficacy of endocrine therapies, resistance remains a problem. Therefore, there is an immediate need for new, effective therapies in ER+ BC. In this study, we have explored the role of a potent CDK4/6 inhibitor called palbociclib. In order to identify alterations in protein abundance between the responsive and resistant setting, we generated a panel of palbociclib-sensitive and resistant cell lines and did quantitative, shotgun proteomics using dimethyl labelling. Palbociclib sensitive cell lines (wt-MCF7 or MCF7-LTED) were cultured in phenol red-free RPMI supplemented with 10% FBS and 1nM estradiol or 10% dextran-coated charcoal (DCC) respectively. Thereafter, palbociclib resistant cell lines were generated using 1μΜ palbociclib concentration. Samples were harvested at baseline and at the point of resistance.
Project description:Estrogen-responsive genes were identified by transcript profiling of estrogen-treated MCF-7 breast cancer cells. The gene expression profile generated after estrogen treatment was compared with that following inducible expression of c-Myc or c-Zip (a deletion mutant of c-Myc that lacks the N-terminal transactivation domains) in clonal MCF-7 cell lines. Experiment Overall Design: RNA was collected in three independent experiments, each including parental MCF-7 cells treated with 17b-estradiol (E2) or ethanol (EtOH), zinc-treated p-delta-MT-c-Myc cells, zinc-treated p-delta-MT-c-Zip cells and zinc-treated empty vector (p-delta-MT) cells. Cells were arrested for 48 h with 10 nM ICI 182780 and then treated for 6 h with either 100 nM E2 or ethanol vehicle, or 75 mM zinc for the stably transfected cell lines.
Project description:To further study gene expression regulated by 17b-estradiol in uteri, we have employed whole gene microarray profiling to identify genes specifically regulated by this site of methylation of ERa (Arg260). Control littermates were used named WT.
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.
