The NEET proteins mitoNEET (mNT) and nutrient-deprivation autophagy factor-1 (NAF-1) are required for cancer cell proliferation and resistance to oxidative stress. MitoNEET and NAF-1 are also implicated in a number of other human pathologies including diabetes, neurodegeneration and heart disease, as well as in development, differentiation and aging. Previous studies suggested that mNT and NAF-1 could function in the same pathway in cancer cells, preventing the over-accumulation of iron and reactive oxygen species (ROS) in mitochondria. Nevertheless, it is unknown whether these two proteins interact in cells, and how they mediate their function. Here we demonstrate, using yeast two-hybrid, in vivo bimolecular fluorescence complementation (BiFC), direct coupling analysis (DCA), RNA- sequencing, ROS and iron imaging, and single and double shRNA lines with suppressed mNT, NAF-1 and mNT/NAF-1 expression, that mNT and NAF-1 interact in cancer cells and function in the same cellular pathway. We further show using an in vitro cluster transfer assay that mNT can transfer its clusters to NAF-1. Our study suggests that mNT and NAF-1 could function as part of an iron-sulfur (2Fe-2S) cluster relay to maintain the levels of iron and Fe-S clusters under control in the mitochondria of cancer cells, thereby preventing the activation of apoptosis and/or autophagy and thus promoting rapid cellular proliferation. Overall design: Examination of the effect of suppression of mNT in the breast cancer cell line MCF-7. Two sample types were analyzed, MCF-7 suppressed for mNT and MCF-7 Empty vector control, three replicates for each.
Interactions between mitoNEET and NAF-1 in cells.
Specimen part, Cell line, Subject
View SamplesNutrient autophagy factor 1 (NAF-1) is an iron-sulfur protein found on the outer mitochondrial membrane and the ER. Recent studies highlighted an important role for NAF-1 in regulating autophagy via interaction with BCL-2. We recently reported that the level of NAF-1 is elevated in cancer cells and that NAF-1 is required for tumor growth. Here we report that shRNA suppression of NAF-1 results in the activation of apoptosis in xenograft tumors and cancer cells grown in culture. Suppression of NAF-1 resulted in a depletion in the cytosolic iron pool, facilitated uptake of iron, and accumulation of iron and ROS in mitochondria, a shift to glycolysis and glutaminolysis, and the activation of cellular stress pathways associated with HIF1a, AMPK and mTOR. Suppression of NAF-1 in breast cancer cells appears therefore to reduce their tumorigenicity by interfering with cellular iron distribution and energy metabolism resulting in the activation of apoptosis. Overall design: Examination of the effect of suppression of NAF-1 in the breast cancer cell line MCF-7. Two sample types were analyzed, MCF-7 suppressed for NAF-1 and MCF-7 Empty vector control, three replicates for each.
Activation of apoptosis in NAF-1-deficient human epithelial breast cancer cells.
No sample metadata fields
View SamplesHepatitis C virus (HCV) is widely used to investigate host-virus interactions and cellular responses to infection have been extensively studied in vitro. In human liver, interferon (IFN) stimulated gene expression can mask direct transcriptional responses to virus infection. To better characterize the direct effects of HCV infection in vivo, we analyze the transcriptomes of HCV-infected patients lacking an activated endogenous IFN system. We show that the expression changes observed in these patients predominantly reflect immune cell infiltrates rather than changes in cell-intrinsic metabolic pathways. We also investigate the transcriptomes of patients with endogenous IFN activation, which paradoxically cannot eradicate viral infection. We find that most IFN-stimulated genes (ISGs) are induced by both the endogenous IFN system and by recombinant IFN therapy, but with significantly higher induction levels in the latter. We conclude that the innate host immune response in chronic hepatitis C is too weak to clear the virus. Overall design: In this study, we aimed to disentangle the direct and indirect effects of HCV infection on cellular transcriptional profiles, by performing a detailed characterization of the gene expression changes associated with HCV infection, endogenous IFN system activation and pegIFNa treatment in the human liver. With this objective, we generated and analyzed high-throughput transcriptome sequencing profiles from liver biopsies derived from different categories of HCV-infected and non-infected patients, prior to and during treatment. First, to unveil HCV-induced cell-autonomous effects and to separate them from IFN-induced changes in the transcriptome, we selected liver biopsies from patients with chronic hepatitis C (CHC) without hepatic ISG induction, and compared them with un-infected control biopsies. Second, we examined the transcriptomic changes associated with the endogenous activation of the IFN system. Finally, we analyzed the gene expression changes resulting from pegIFNa/ribavirin treatment, by comparing transcriptome data from liver biopsies obtained before treatment and at different time points during the first week of therapy.
Transcriptional response to hepatitis C virus infection and interferon-alpha treatment in the human liver.
Specimen part, Treatment, Subject
View SamplesDespite decades of interest, the mechanisms that control Hox gene expression are not yet fully understood. It was recently proposed that Hotair, a lncRNA transcribed from the HoxC cluster, regulates HoxD gene expression via Polycomb targeting and thus is important for correct skeletal development. However, genetic manipulations of the locus led to conflicting results regarding the roles of Hotair. Here, we analyze the molecular and phenotypic consequences of deleting the Hotair locus in vivo. In contradiction with previous findings, we show that deleting Hotair has no detectable effect on HoxD gene expression in vivo. We could not observe any morphological alteration in mice lacking the Hotair locus. However, we find a significant impact of deleting Hotair on the expression of neighboring genes Hoxc11 and Hoxc12. Our results do not support an RNA-dependent role for Hotair in vivo, but argue in favor of a DNA-dependent effect of Hotair deletion on the transcriptional landscape in cis. Overall design: We micro-dissected wild type and Del(Hotair)-/- E12.5 embryos into 6 segments: forelimbs (FL), hindlimbs (HL), genital tubercle (GT), trunk section corresponding to the lumbar/sacral region (T1); trunk section corresponding to the sacral/caudal region (T2) and trunk section corresponding to the caudal region (T3). We generated strand-specific RNA-seq data for each segment, in two biological replicates and we performed differential expression analyses for each tissue. Furthermore, we analyzed the impact of deleting the Hotair locus on the local transcriptional landscape, in the HoxC cluster.
Hotair Is Dispensible for Mouse Development.
Specimen part, Cell line, Subject
View SamplesIn this work we have analyzed the transcriptomic profiles of E9 mouse embryos. We show that Hoxd1 and Haglr transcripts are absent after targeted deletion of the CpG: 114 island. Overall design: RNA-seq analysis of trunk from the anterior limit of the forelimb bud to the tailbud, aiming to exclude all extra-embryonic, head, cervical and heart tissues. Individuals 443 (wt) and 445 (Del(CpG114) homozygous), were siblings from the same dam, while biological replicates 456 (wt) and 455 (Del(CpG114) homozygous) were siblings from another dam.
Control of growth and gut maturation by <i>HoxD</i> genes and the associated lncRNA <i>Haglr</i>.
Specimen part, Cell line, Subject
View SamplesTo determine the physiological targets of the NELF complex, and provide insight into the mechanism of NELF activity in vivo.
NELF-mediated stalling of Pol II can enhance gene expression by blocking promoter-proximal nucleosome assembly.
No sample metadata fields
View SamplesWe use mice containing a gene trap in the first intron of the Rest gene, which effectively eliminates transcription from all coding exons, to prematurely remove REST from neural progenitors. We find catastrophic DNA damage that occurs during S-phase of the cell cycle and concominant with activation of p53 pro-apoptotic sgnalling, with consequences including abnormal chromosome separation, apoptosis, and smaller brains.
The REST remodeling complex protects genomic integrity during embryonic neurogenesis.
Specimen part
View SamplesWe use mice containing a gene trap in the first intron of the Rest gene, which effectively eliminates transcription from all coding exons, to prematurely remove REST from neural progenitors. We find catastrophic DNA damage that occurs during S-phase of the cell cycle, with consequences including abnormal chromosome separation, apoptosis, and smaller brains. Further support for persistent effects is the latent appearance of proneural glioblastomas in adult mice also lacking the tumor suppressor, p53. A Rest deficient mouse line generated previously, using a conventional gene targeting approach, does not exhibit these phenotypes, likely due to a remaining C terminal peptide that still binds chromatin and recruits REST chromatin modifiers.Our results indicate that REST-mediated chromatin remodeling is required for proper S-phase dynamics, prior to its well-established role in relieving repression of neuronal genes at terminal differentiation.
The REST remodeling complex protects genomic integrity during embryonic neurogenesis.
Specimen part
View SamplesWe have used an agnostic approach to identify drug combinations by using combination high throughput screening (cHTS) technology and make the surprising discovery that adenosine A2A and beta-2 adrenergic receptor agonists are highly synergistic, selective and novel agents that enhance glucocorticoid activity in B-cell malignancies.
Adenosine A2A and beta-2 adrenergic receptor agonists: novel selective and synergistic multiple myeloma targets discovered through systematic combination screening.
Specimen part, Cell line
View SamplesRegulation of gene expression is integral to the development and survival of all organisms. Transcription begins with the assembly of a pre-initiation complex at the gene promoter, followed by initiation of RNA synthesis and the transition to productive elongation. In many cases, recruitment of RNA polymerase II (Pol II) to a promoter is necessary and sufficient for activation of gene. However, there are a few notable exceptions to this paradigm, including heat shock genes and several proto-oncogenes, whose expression is attenuated by regulated stalling of polymerase elongation within the promoter-proximal region. To determine the importance of polymerase stalling for transcription regulation, we performed a genome-wide search for Drosophila genes with promoter-proximally stalled Pol II. Our data reveal that stalling is widespread, occurring at hundreds of genes that respond to stimuli and developmental signals, indicating a role for regulation of polymerase elongation in the transcriptional responses to dynamic environmental and developmental cues.
RNA polymerase is poised for activation across the genome.
No sample metadata fields
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