We performed a polysomal RNA-Seq screen in non-malignant breast epithelial (MCF10A) and TNBC (MDA-MB-231) cells exposed to normoxic or hypoxic conditions and/or treated with an mTOR pathway inhibitor. Analysis of both the transcriptome and the translatome identified mRNA transcripts translationally activated or repressed by hypoxia in an mTOR-dependent or -independent manner. The mRNA populations of each sample were converted to cDNA libraries using the TruSeq protocol and then sequenced using a HiSeq 2000 machine. Paired-end reads were mapped against the reference human genome (GRCh38) with STAR v2.5.1b (ENCODE parameters for long RNA) and GENCODE v24 annotation. Gene quantification was performed using RSEM v1.2.28 with default parameters. Only protein-coding genes were included in the analysis. Normalization of the count matrix was performed with the TMM method of the edgeR R package. Polysomal RNA (P) and RNA total (T) fold changes across conditions were calculated with edgeR. Significant genes (FDR < 5% for MCF10A cells and FDR < 10% for MDA-MB-231 cells) in polysomes were selected for translational efficiency calculation (log2FC RNA polysomes/log2FC RNA total). Genes with a z-score > 1.5 were considered to have an increased translational efficiency and genes with a z-score < –1.5 were considered to have a decreased translational efficiency. GO enrichment analysis of significant genes was performed with the DAVID database. Overall design: RNA-Seq profiles in polysomes vs total in Normoxia, Hypoxia, Hypoxia + PP242, Normoxia + PP242 in MCF10A and MDA-MB-231 cell lines
Hypoxia-mediated translational activation of ITGB3 in breast cancer cells enhances TGF-β signaling and malignant features <i>in vitro</i> and <i>in vivo</i>.
Cell line, Treatment, Subject
View SamplesHER2 is a tyrosine kinase receptor causally involved in cancer. A subgroup of breast cancer patients with particularly poor clinical outcome expresses a heterogeneous collection of HER2 carboxy-terminal fragments (CTFs). However, since the CTFs lack the extracellular domain that drives dimerization and subsequent activation of full-length HER2, they are in principle expected to be inactive. Here we present evidence that at low expression levels one of these fragments, 611-CTF, activated multiple signaling pathways because of its unanticipated ability to constitutively homodimerize. A transcriptomic analysis revealed that 611-CTF specifically controlled the expression of genes that we found correlated with poor prognosis in breast cancer. Among the 611-CTF-regulated genes were several that previously have been linked to metastasis, including MET, EPHA2, MMP1, IL11, ANGPTL4 and different Integrins. Transgenic mice overexpressing HER2 in the mammary gland develop tumors only after acquisition of activating mutations in the transgene. In contrast, we show that expression of 611-CTF led to development of aggressive and invasive mammary tumors without the need for mutations. These results demonstrate that 611-CTF is a potent oncogene capable of promoting mammary tumor progression and metastasis.
A naturally occurring HER2 carboxy-terminal fragment promotes mammary tumor growth and metastasis.
Cell line, Time
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
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>.
No sample metadata fields
View SamplesCocoa protein content is a very interesting source for isolation of antioxidant bio-peptides, which can be used for the prevention of age-related diseases. We use microarrays to study the global genome expression of C. elegans fed with a peptide (13L) isolated from cocoa.
A cocoa peptide protects Caenorhabditis elegans from oxidative stress and β-amyloid peptide toxicity.
No sample metadata fields
View SamplesZXDC1 augments the expression of various markers of monocyte/macrophage differentiation when over-expressed in the U937 cell line treated with the phorbol ester PMA. Likewise, knockdown of ZXDC1 restricts the induced expression of these markers. We sought to identify specfic gene targets of ZXDC1 during the process of monocyte/macrophage differentiation in U937 by performing gene expression profiling in cells exhibiting reduced expression of ZXDC1 compared to controls.
The zinc finger transcription factor ZXDC activates CCL2 gene expression by opposing BCL6-mediated repression.
Specimen part, Cell line
View SamplesNumerous studies have shown that resistance to oxidative stress is crucial to stay healthy and to reduce the adverse effects of aging. Accordingly, nutritional interventions using antioxidant food-grade compounds or food products are currently an interesting option to help improve health and quality of life in the elderly. Live lactic acid bacteria (LAB) administered in food, such as probiotics, may be good antioxidant candidates. Nevertheless, information about LAB-induced oxidative stress protection is scarce. To identify and characterize new potential antioxidant probiotic strains, we have developed a new functional screening method using the nematode Caenorhabditis elegans as host. C. elegans were fed on different LAB strains (78 in total) and nematode viability was assessed after oxidative stress (3mM and 5mM H2O2). One strain, identified as Lactobacillus rhamnosus CNCM I-3690, protected worms by increasing their viability by 30% and, also, increased average worm lifespan by 20%. We performed a transcriptomic analysis of C. elegans fed with this strain and showed that increased lifespan is correlated with differential expression of the DAF-16/insulin-like pathway, which is highly conserved in humans.
Anti-inflammatory Lactobacillus rhamnosus CNCM I-3690 strain protects against oxidative stress and increases lifespan in Caenorhabditis elegans.
Time
View SamplesPerinatal nutritional imbalances may have long-lasting consequences on health and disease, increasing risk of obesity, insulin resistance, type 2 diabetes or cardiovascular disease. This idea has been conceptualized in the Developmental Origins of Health and Disease Hypothesis (DOHaD). In addition, there is evidence that such early-programmed phenotypes can be transmitted to the following generation(s). It is proposed that, environmentally induced, transmission of disease risk is mediated by epigenetic mechanisms.
In utero undernutrition in male mice programs liver lipid metabolism in the second-generation offspring involving altered Lxra DNA methylation.
Specimen part, Treatment
View SamplesIn the diploid genome, genes come in two copies, which can have different DNA sequence and where one is maternal and one is paternal. In a particular cell, a gene could potentially be expressed from both copies (biallelic expression) or only one (monoallelic). We performed RNA-Sequencing on individual cells, from zygote to the cells of the late blastocyst, and also individual cells from the adult liver. Using first generation crosses between two distantly related mouse strains, CAST/Ei and C57BL/6, we determined the expression separately from the maternal and paternal alleles. We found that half of the genes were expressed by only one allele, randomly so that some cells would express the paternal allele, some the maternal and a few cell both alleles. We also observed the spread of the progressive inactivation of the paternal X chromosome. Overall design: First generation mouse strain crosses were used to study monoallelic expression on the single cell level
Single-cell RNA-seq reveals dynamic, random monoallelic gene expression in mammalian cells.
No sample metadata fields
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