Project description:Endocrine therapies targeting the proliferative effect of 17β-estradiol (17βE2) through estrogen receptor α (ERα) are the most effective systemic treatment of ERα-positive breast cancer. However, most breast tumors initially responsive to these therapies develop resistance through a molecular mechanism that is not yet fully understood. The long-term estrogen-deprived (LTED) MCF7 cell model has been proposed to recapitulate acquired resistance to aromatase inhibitors (AIs) in postmenopausal women. To elucidate this resistance, genomic, transcriptomic and molecular data were integrated into the time course of MCF7-LTED adaptation. Dynamic and widespread genomic changes were observed, including amplification of the ESR1 locus consequently linked to an increase in ERα. Dynamic transcriptomic profiles were also observed that correlated significantly with genomic changes and were influenced by transcription factors known to be involved in acquired resistance or cell proliferation (e.g. IRF1 and E2F1, respectively) but, notably, not by canonical ERα transcriptional function. Consistently, at the molecular level, activation of growth factor signaling pathways by EGFR/ERBB/AKT and a switch from phospho-Ser118 (pS118)- to pS167-ERα were observed during MCF7-LTED adaptation. Evaluation of relevant clinical settings identified significant associations between MCF7-LTED and breast tumor transcriptome profiles that characterize ERα-negative status, early response to letrozole and recurrence after tamoxifen treatment. This study proposes a mechanism for acquired resistance to estrogen deprivation that is coordinated across biological levels and independent of canonical ERα function. LTED (long term estrogen deprived) cell line was generated from MCF-7 cells by long-term culture under estrogen deprivated conditions. And RNA samples were obtained after 3, 15, 30, 90, 120, 150 and 180 days.
Project description:Endocrine therapies targeting the proliferative effect of 17β-estradiol (17βE2) through estrogen receptor α (ERα) are the most effective systemic treatment of ERα-positive breast cancer. However, most breast tumors initially responsive to these therapies develop resistance through a molecular mechanism that is not yet fully understood. The long-term estrogen-deprived (LTED) MCF7 cell model has been proposed to recapitulate acquired resistance to aromatase inhibitors (AIs) in postmenopausal women. To elucidate this resistance, genomic, transcriptomic and molecular data were integrated into the time course of MCF7-LTED adaptation. Dynamic and widespread genomic changes were observed, including amplification of the ESR1 locus consequently linked to an increase in ERα. Dynamic transcriptomic profiles were also observed that correlated significantly with genomic changes and were influenced by transcription factors known to be involved in acquired resistance or cell proliferation (e.g. IRF1 and E2F1, respectively) but, notably, not by canonical ERα transcriptional function. Consistently, at the molecular level, activation of growth factor signaling pathways by EGFR/ERBB/AKT and a switch from phospho-Ser118 (pS118)- to pS167-ERα were observed during MCF7-LTED adaptation. Evaluation of relevant clinical settings identified significant associations between MCF7-LTED and breast tumor transcriptome profiles that characterize ERα-negative status, early response to letrozole and recurrence after tamoxifen treatment. This study proposes a mechanism for acquired resistance to estrogen deprivation that is coordinated across biological levels and independent of canonical ERα function.
Project description:The human oestrogen-positive breast cancer cell line MCF7 was cultured in phenol red-free RPMI medium supplemented with 10% fetal bovine serum, 10mg/ml insulin and 1nM estradiol (E2) and was referred to as wild-type MCF7. The wt-MCF7 cells were passaged weekly and medium was replenished every two to three days. To model acquisition of resistance to long term estrogen deprivation (LTED) on an aromatase inhibitor (AI), wt-MCF7 cells were cultured in phenol red-free RPMI medium supplemented with 10% dextran charcoal-stripped bovine serum (DCC) and 10mg/ml insulin. RNA was extracted from the LTED monolayers using RNeasy columns (Qiagen) according to manufacturerメs protocol. RNA amplification, labeling and hybridization on HumanWG-6 v3 Expression BeadChips were performed according to the manufacturer's instructions (http://www.illumina.com) to assess changes in gene expression during adaptation to LTED.
Project description:We performed ChIP-seq on MCF7 cells in an effort to discern differential binding patterns between wild type MCF7s and MCF7s that have acquired resistance to Tamoxifen and Estrogen deprivation. Furthermore, we also performed an HAtag ChIP on a DOX inducible RUNX2 overexpression MCF7 cell line. We also performed RNA-seq on MCF7 cells to determine transciptional changes after acquisition of Tamoxifen resistance, and also transciptional changes in a DOX inducible RUNX2 overexpression model.
Project description:We report the first discovery of naturally occurring ESR1Y537C and ESR1Y537S mutations in MCF7 and MCF7 ESR1-positive cell-lines after acquisition of resistance to long-term-estrogen-deprivation (LTED) and subsequent resistance to fulvestrant (ICIR).
Project description:We report the first discovery of naturally occurring ESR1Y537C and ESR1Y537S mutations in MCF7 and SUM44 ESR1-positive cell-lines after acquisition of resistance to long-term-estrogen-deprivation (LTED) and subsequent resistance to fulvestrant (ICIR).
Project description:Catechol-O-methyl transferase (COMT) is involved in detoxification of catechol estrogens, playing cancer-protective role in cells producing or utilizing estrogen. Moreover, COMT suppressed migration potential of breast cancer cells. To delineate COMT role in metastasis of estrogen receptor dependent BC, we investigated the effect of COMT overexpression on invasion, transcriptome, proteome and interactome of MCF7 cells, a luminal A breast cancer model, stably transduced with lentiviral vector carrying COMT gene (MCF7-COMT). This PRIDE project includes quantitative analysis results for the total proteome LC-DIA-MS/MS experiment evaluating COMT overexpression in MCF7 breast cancer cell line, and results of pulldown analysis of COMT-interacting proteins in MCF7 cells.
Project description:To investigate molecular mechanisms of resistance, we used two different in vivo xenograft models of estrogen receptor-positive (ER+) breast cancer, with or without HER2 over-expression (MCF7/HER2-18 and MCF7 wt, respectively). Mice with established tumors were assigned to the following treatment groups: continued estrogen supplementation (E2), estrogen deprivation (ED), ED plus tamoxifen (Tam), all with or without the EGFR tyrosine kinase inhibitor gefinitinib (G). Another group received ED plus the antiestrogen fulvestrant (MCF7 wt only). Tumors with acquired or de novo resistance to these endocrine therapies were profiled for mRNA expression using Affymetrix Genechip arrays. Keywords: multiple group comparison