For this study we selected a gene, -synuclein (SNCA), that is consistently under-expressed in MCF7 cells and breast tumors. Following transfection with an SNCA expression construct, two stable MCF7 clones (named MCF7-SNCA #1 and 2) were selected and examined for expression differences relative to the parental MCF7 cells.
Cancer develops, progresses and responds to therapies through restricted perturbation of the protein-protein interaction network.
Specimen part, Cell line
View SamplesEndocrine therapies targeting the proliferative effect of 17-estradiol (17E2) through estrogen receptor (ER) are the most effective systemic treatment of ER-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 ER. 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 ER 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-ER were observed during MCF7-LTED adaptation. Evaluation of relevant clinical settings identified significant associations between MCF7-LTED and breast tumor transcriptome profiles that characterize ER-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 ER function.
Biological reprogramming in acquired resistance to endocrine therapy of breast cancer.
Specimen part, Cell line
View SamplesLactoferrin is a highly multifunctional protein. Indeed, it is involved in many physiological functions, including regulation of iron absorption and immune responses.
A nutritional supplement containing lactoferrin stimulates the immune system, extends lifespan, and reduces amyloid <i>β</i> peptide toxicity in <i>Caenorhabditis elegans</i>.
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View SamplesThe ability to regenerate or recover from injuries varies greatly not only between species but also between tissues and organs or developmental stages of the same species. The mechanisms behind these different regenerative capabilities are ultimately dependent on the control of genome activity, determined by a complex interplay of regulatory elements functioning at the level of chromatin. Resetting of gene expression patterns during injury responses is, thus, shaped by the coordinated action of genomic regions (enhancers, silencers) that integrate the activity of multiple sequence-specific DNA binding proteins (transcription factors and cofactors). Using genome- wide approaches to interrogate chromatin function here we identify the regulatory elements governing tissue recovery in Drosophila wing imaginal discs, which show a high regenerative capacity after genetically induced cell death. Our findings point to a global co-regulation of gene expression and provide evidence for Damage Responding Regulatory Elements (DRRE), some of which are novel whereas others are also used in other tissues or developmental stages. Overall design: We collected data at different time points (0, 15 and 25h) after apoptosis induction. These time periods were selected because they included the most important transcriptional responses to apoptosis, ranging from the earliest gene expression up to complete re-patterning. Discs kept at the same conditions without inducing cell death were used as controls.
Damage-responsive elements in <i>Drosophila</i> regeneration.
Specimen part, Subject
View SamplesAnalysis of the expression profiles of MCF7 cells transduced with a control shRNA and an TSC2-targeted shRNA (leading to tuberin depletion).
Lymphangioleiomyomatosis Biomarkers Linked to Lung Metastatic Potential and Cell Stemness.
Cell line
View SamplesWe describe a function of focal adhesion kinase (FAK) in driving anti-tumor immune evasion. The kinase activity of nuclear-targeted FAK in squamous cancer cells drives exhaustion of CD8+ T-cells and recruitment of regulatory T-cells by transcriptionally regulating chemokine/cytokine and ligand-receptor networks, including transcription of Ccl5 that is crucial. These changes inhibit antigen-primed cytotoxic CD8+ T-cell activity, permitting growth of FAK-expressing tumors.
Nuclear FAK controls chemokine transcription, Tregs, and evasion of anti-tumor immunity.
Specimen part
View SamplesProliferative zone chondrocytes were microdissected from control and Ift88-deleted growth plates to determine gene expression profiles regulated by primary cilia.
Ift88 regulates Hedgehog signaling, Sfrp5 expression, and β-catenin activity in post-natal growth plate.
Specimen part
View SamplesTo identify novel therapeutic opportunities for patients with acquired resistance to endocrine treatments in breast cancer, we applied a high-throughput drug screen. The IC50 values were determined for MCF7 and MCF7-LTED cells.
VAV3 mediates resistance to breast cancer endocrine therapy.
Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Stem cell-like transcriptional reprogramming mediates metastatic resistance to mTOR inhibition.
Specimen part, Cell line
View SamplesInhibitors of the mechanistic target of rapamycin (mTOR) are currently used to treat advanced metastatic breast cancer. However, whether an aggressive phenotype is sustained through adaptation or resistance to mTOR inhibition remains unknown. Here, complementary studies in human tumors, cancer models and cell lines reveal transcriptional reprogramming that supports metastasis in response to mTOR inhibition. This cancer feature is driven by EVI1 and SOX9. EVI1 functionally cooperates with and positively regulates SOX9, and promotes the transcriptional upregulation of key mTOR pathway components (REHB and RAPTOR) and of lung metastasis mediators (FSCN1 and SPARC). The expression of EVI1 and SOX9 is associated with stem cell-like and metastasis signatures, and their depletion impairs the metastatic potential of breast cancer cells. These results establish the mechanistic link between resistance to mTOR inhibition and cancer metastatic potential, thus enhancing our understanding of mTOR targeting failure.
Stem cell-like transcriptional reprogramming mediates metastatic resistance to mTOR inhibition.
Specimen part
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