Expression profiling of genes induced by atovaquone treatment
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE46575 | GEO | 2018/12/21
REPOSITORIES: GEO
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Project description:Eukaryotic translation initiation factor 4E (eIF4E)–binding protein 1 (4E-BP1) inhibits cap-dependent translation in eukaryotes by competing with eIF4G for an interaction with eIF4E. Phos-phorylation at Ser-83 of 4E-BP1 occurs during mitosis through the activity of cyclin-dependent kinase 1 (CDK1)/cyclin B rather than through canonical mTOR kinase activity. Here, we investi-gated the interaction of eIF4E with 4E-BP1 or eIF4G during interphase and mitosis. We observed that 4E-BP1 and eIF4G bind eIF4E at similar levels during interphase and mitosis. The most highly phosphorylated mitotic 4E-BP1 isoform (δ) did not interact with eIF4E, whereas a distinct 4E-BP1 phospho-isoform, EB-γ—phosphorylated at Thr-70, Ser-83, and Ser-101—bound to eIF4E during mitosis. Two-dimensional gel electropho-retic analysis corroborated the identity of the phosphorylation marks on the eIF4E-bound 4E-BP1 isoforms and uncovered a population of phosphorylated 4E-BP1 molecules lacking Thr-37/Thr-46–priming phosphorylation. Moreover, proximity ligation assays for phospho–4E-BP1 and eIF4E revealed different in situ interactions during interphase and mitosis. The eIF4E:eIF4G interaction was not inhibited, but rather increased in mitotic cells, consistent with active translation initiation during mitosis. Phospho-defective substitution of 4E-BP1 at Ser-83 did not change global translation or individual mRNA translation profiles as measured by single-cell nascent protein synthesis and eIF4G RNA-immunoprecipitation sequencing. Mitotic 5’-terminal oligopyrimidine RNA translation was active and, unlike interphase translation, resistant to mTOR inhibition. Our findings reveal the phosphorylation profiles of 4E-BP1 isoforms and their interactions with eIF4E throughout the cell cycle and indicate that 4E-BP1 does not specifically inhibit translation initiation during mitosis.
2019-06-14 | GSE131668 | GEO
Project description:Evidence has long suggested that epidermal growth factor receptor (EGFR) may play a prominent role in triple-negative breast cancer (TNBC) pathogenesis, but clinical trials of EGFR inhibitors have yielded disappointing results. Using a candidate drug screen, we discovered that inhibition of cyclin-dependent kinases 12 and 13 (CDK12/13) dramatically sensitizes diverse models of TNBC to EGFR blockade. This combination therapy drives cell death through the 4E-BP1-dependent suppression of the translation and translation-linked turnover of driver oncoproteins, including MYC. A genome-wide CRISPR/Cas9 screen identified the CCR4-NOT complex as a major determinant of sensitivity to the combination therapy whose loss renders 4E-BP1 unresponsive to drug-induced dephosphorylation, thereby rescuing MYC translational suppression and promoting MYC stability. The central roles of CCR4-NOT and 4E-BP1 in response to the combination therapy were further underscored by the observation of CNOT1 loss and rescue of 4E-BP1 phosphorylation in TNBC cells that naturally evolved therapy resistance. Thus, pharmacological inhibition of CDK12/13 reveals a long proposed EGFR dependence in TNBC that functions through the cooperative regulation of translation-coupled oncoprotein stability.
2023-09-27 | GSE221475 | GEO
Project description:Although the mTOR-4E-BP1 signaling pathway is implicated in aging and aging-related disorders, the role of 4E-BP1 in regulating human stem cell homeostasis remains largely unknown. Here, we report that the expression of 4E-BP1 decreases along with the senescence of human mesenchymal stem cells (hMSCs). Genetic inactivation of 4E-BP1 in hMSCs accelerates cellular senescence, compromises mitochondrial respiration and increases mitochondrial ROS production. Mechanistically, the absence of 4E-BP1 destabilizes proteins in mitochondrial respiration complexes, especially several key subunits of the complex III including UQCRC2. Ectopic expression of 4E-BP1 attenuates mitochondrial abnormalities and alleviates cellular senescence in 4E-BP1-deficient hMSCs as well as in physiologically aged hMSCs. These findings together demonstrate that 4E-BP1 functions as a geroprotector to alleviate human stem cell senescence and maintain mitochondrial homeostasis, particularly for the mitochondrial respiration complex III and provide a new potential target to counteract human stem cell senescence.
2023-05-10 | PXD033301 | Pride
Project description:Activation of the mechanistic target of rapamycin complex 1 (mTORC1) contributes to the development of chronic pain. However, the specific mechanisms by which mTORC1 causes hypersensitivity remain elusive. The eukaryotic initiation factor 4E-binding protein 1 (4E-BP1) is a key mTORC1 downstream effector that represses translation initiation. Here we show that nociceptor-specific deletion of 4E-BP1, mimicking activation of mTORC1-dependent translation, is sufficient to cause mechanical hypersensitivity.
2023-03-27 | GSE227978 | GEO
Project description:Discodermolide treatment of A549 results in senescence. We compared cells resistant to disco-induced senescence to those that are sensitive to senescence induction. We also examined the gene expression of resistant (AD32) cells overexpressing 4E-BP1, a protein known to restore sensitivity to discodermolide in these cells. Total RNA was collected from A549, A549 disco, AD32, and AD32 4E-BP1 cells and gene expression profiles were examined.
2010-12-08 | E-GEOD-25904 | biostudies-arrayexpress
Project description:Spinal microglia play a pivotal role in the development of neuropathic pain. Peripheral nerve injury induces changes in the transcriptional profile of microglia, including increased expression of components of translational machinery. Whether microglial protein synthesis is stimulated following nerve injury and has a functional role in mediating pain hypersensitivity is unknown. Here, we show that nascent protein synthesis is upregulated in spinal microglia following peripheral nerve injury. Stimulating mRNA translation in microglia, via selective ablation of the translational repressor, eukaryotic initiation factor 4E-binding protein 1 (4E-BP1), promoted the transition of microglia to a reactive state and induced mechanical hypersensitivity. Conversely, inhibiting microglial translation by expressing mutant 4E-BP1 in microglia attenuated their peripheral nerve injury-induced activation and alleviated neuropathic pain. Thus, the stimulation of 4E-BP1-dependent translation promotes microglia reactivity and mechanical hypersensitivity, whereas its inhibition alleviates neuropathic pain.
2024-01-31 | GSE254472 | GEO
Project description:Pancreatic ductal adenocarcinoma (PDAC) relies on hyper-activated protein synthesis. Consistently, human and mouse PDAC lose expression of the translational repressor and mTOR target 4E-BP1. Using genome-wide polysome-profiling, we here explore mRNAs whose translational efficiencies depend on the mTOR/4E-BP1 axis in Miapaca-2 cells. This was performed by isolating cytoplasmic and efficiently translated (heavy polysome-associated) mRNAs from MiaPaca-2 cells upon PP242-mediated mTOR inhibition
2019-09-18 | GSE137553 | GEO
Project description:Cyclin-dependent kinases 13 (CDK13) has been suggested to phosphorylate RNA polymerase II and is involved in transcriptional activation. However, whether CDK13 catalyzes other protein substrates and how CDK13 contributes to tumorigenesis remain largely unclear. Herein, we identify key translation machinery components 4E-BP1 and eIF4B as novel CDK13 substrates. CDK13 directly phosphorylates 4E-BP1 at Thr46 and eIF4B at Ser422 such that genetic or pharmacological inhibition of CDK13 perturbs RNA translation. Polysome profiling analysis shows that MYC oncoprotein synthesis depends on the CDK13-regulated translation in colorectal cancer (CRC), and CDK13 is required for CRC cell proliferation. As mTORC1 has been shown to phosphorylate the 4E-BP1 and eIF4B, knockdown or inhibition of CDK13 in combination with mTORC1 inhibitor rapamycin further dephosphorylates 4E-BP1 and eIF4B and blocks protein synthesis. As a result, dual inhibition of CDK13 and mTORC1 accelerated CRC cell death and again MYC were significantly downregulated upon combination treatment. These findings demonstrate a pro-tumorigenic role of CDK13 in CRC and shed light on the role of CDK13 in protein synthesis by direct phosphorylation of translation initiation factors. Therefore, therapeutic targeting of CDK13 alone or in combination with rapamycin may pave a new way for CRC treatment.
2023-03-09 | GSE224287 | GEO
Project description:Background: Interval breast cancers can occur through failure to detect an abnormality at the time of screening (missed interval cancer), or as a new event after a negative screen (true interval cancer). The development and progression of true interval tumors (TIBC) is known to be different than screen-detected tumors (SDBC). However, much work still needs to be done to understand the biological characteristics and clinical behaviour of these TIBC. Objectives: To characterize the gene expression profile in TIBC and SDBC aimed to identify biological markers that may be associated with the emergence of symptomatic breast cancer in the screening interval. Material and Methods: An unsupervised exploratory gene expression profile analysis was performed among 10 samples (discovery set, TIBC=5 and SDBC=5) using Affymetrix Human Gene 1.0 ST arrays and interpreted by Ingenuity Pathway Analysis. Differential expression of selected genes was confirmed in validation series of 91 patients (TIBC=12 and SDBC=79) by immunohistochemistry and 24 patients (TIBC=8 and SDBC=16) by RT-qPCR, expanding the analysis to other genes in same pathway (mTOR, 4E-BP1, eIF-4G and S6). Results: Exploratory gene expression analysis identified 1060 transcripts with a p value <0.05 and 132 transcripts with an adjusted p value <0.01 difference between TIBC and SDBC samples. Based on biological implications in breast cancer, four genes were selected for further validation: CP (ceruloplasmin) and RPS6KB2 (ribosomal protein S6 kinase, 70kDa, polypeptide 2) both up-regulated in TIBC vs SDBC and PTEN (phosphatase and tensin homolog) and TGFBR3 (transforming growth factor beta receptor III), down-regulated in TIBC vs SDBC. Their differential expression was confirmed by RT-qPCR and immunohistochemistry, suggesting mTOR pathway overexpression in TIBC at both mRNA and protein level. Further expanded analysis by immunohistochemistry for mTOR pathway activation, including expression of phosphorylated forms of mTOR, 4E-BP1, eIF-4G, RPS6KB2 and S6, confirmed the upregulation of this pathway in TIBC. Conclusions: TIBC and SDBC shows differential expression profile both at the gene and protein levels. The mTOR signaling is significantly upregulated in TIBC compared with SDBC, suggesting an enhanced aggressiveness of TIBC. Besides, CP may also represent novel immunohistochemical marker helpful in distinguishing between TIBC and SDBC. Further studies with larger sets of patients are guaranteed to verify these findings associated with TIBC. 5 TIBC samples where compared with 5 SDBC
2013-12-23 | E-GEOD-47108 | biostudies-arrayexpress
Project description:Discodermolide treatment of A549 results in senescence. We compared cells resistant to disco-induced senescence to those that are sensitive to senescence induction. We also examined the gene expression of resistant (AD32) cells overexpressing 4E-BP1, a protein known to restore sensitivity to discodermolide in these cells.
2010-12-08 | GSE25904 | GEO