Gene expression profiling of HepG2 cell response to bortezomib in combination with nelfinavir or ISRIB, compounds targeting the eIF2a-ATF4 pathway
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PROVIDER: PRJNA702297 | ENA |
REPOSITORIES: ENA
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Project description:We investigate how modulation of the eIF2alpha-ATF4 stress pathway affects hepatoma cell response to bortezomib. Transcriptome profiling revealed that many ATF4 transcriptional target genes are among the highest upregulated genes in bortezomib-treated HepG2 human hepatoma cells. While pharmacological enhancement of the eIF2alpha-ATF4 pathway activity results in the elevation of the activities of all branches of the unfolded protein response (UPR) and sensitizes cells to bortezomib toxicity, the suppression of ATF4 induction delays bortezomib-induced cell death. The pseudokinase TRIB3, an inhibitor of ATF4, is expressed at a high basal level in hepatoma cells and is strongly upregulated in response to bortezomib. Bortezomib treatment leads to a robust enrichment of TRIB3 binding near genes induced by bortezomib and involved in the ER stress response and cell death. Disruption of TRIB3 increases C/EBP-ATF-driven transcription, augments ER stress and cell death in cells exposed to bortezomib, while TRIB3 overexpression enhances the cell survival. Thus, TRIB3, colocalizing with ATF4 and limiting its transcriptional activity, functions as a factor increasing resistance to bortezomib, while pharmacological over-activation of eIF2alpha-ATF4 can overcome the endogenous restraint mechanisms and sensitize cells to bortezomib.
2021-05-24 | GSE166923 | GEO
Project description:The proteasome is an appealing anti-cancer drug target and the proteasome inhibitor bortezomib has been approved for the treatment of certain types of malignancies. However, the molecular mechanisms underlying cancer cell resistance to bortezomib remain poorly understood. The pseudokinase TRIB3, an inhibitor of ATF4, is expressed at a high basal level in hepatoma cells and is strongly upregulated in response to bortezomib. To map genome-wide chromatin binding loci of TRIB3 protein, we fused a Flag tag to endogenous TRIB3 in HepG2 cells and performed ChIP-Seq. The results demonstrate that TRIB3 predominantly colocalizes with ATF4 on chromatin and the proteins reside in genomic regions containing the C/EBP-ATF motif. Bortezomib treatment leads to a robust enrichment of TRIB3 binding near genes induced by bortezomib and involved in the ER stress response and cell death. Disruption of TRIB3 increases C/EBP-ATF-driven transcription, augments ER stress and cell death in cells exposed to bortezomib, while TRIB3 overexpression enhances the cell survival. Thus, TRIB3, colocalizing with ATF4 and limiting its transcriptional activity, functions as a factor increasing resistance to bortezomib, while pharmacological over-activation of eIF2alpha-ATF4 can overcome the endogenous restraint mechanisms and sensitize cells to bortezomib.
2021-05-24 | GSE166958 | GEO
Project description:ChIP-Seq of TRIB3 and ATF4 in HepG2 cells treated with bortezomib
| PRJNA702470 | ENA
Project description:To identify the target genes of integrated stress reponse (ISR), we have employed whole genome microarray expression in MEF cells. ISR gene setimation under ER stress condition using Perk -/-, Atf4 -/-, eIF2a S51A mutant, Fv2E-PERK MEF cells
2015-09-01 | E-GEOD-49598 | biostudies-arrayexpress
Project description:The integrated stress response (ISR) is a conserved pathway which is activated by cells that are exposed to stress. In lung adenocarcinoma (LUAD), activation of the ATF4 branch of the ISR by particular oncogenic mutations has been linked to the regulation of amino acid metabolism. In the present study, we provide evidence for ATF4 activation across multiple stages and molecular subtypes of human LUAD. In response to extracellular amino acid limitation, LUAD cells with diverse genotypes broadly induce ATF4 in an eIF2α dependent manner, which can be blocked pharmacologically using the integrated stress response inhibitor (ISRIB). Although suppressing eIF2α or ATF4 can trigger different biological consequences, adaptive cell cycle progression and cell migration are particularly sensitive to inhibition of the ISR. These phenotypes specifically require the ATF4 target gene asparagine synthetase (ASNS), which maintains protein translation independently of the mTOR/PI3K pathway. Moreover, NRF2 protein levels and oxidative stress can be modulated by the ISR downstream of ASNS. Finally, we demonstrate that the ISR via ASNS controls the biosynthesis of select proteins, including the cell cycle regulator cyclin B1, which are associated with poor LUAD patient prognosis. Our findings uncover new regulatory layers of the ISR pathway and its control of proteostasis in lung cancer cells as they adapt to metabolic barriers during tumor progression.
2019-10-23 | GSE126232 | GEO
Project description:We recently identified ISRIB as a potent inhibitor of the integrated stress response (ISR). ISRIB renders cells resistant to the effects of eIF2α phosphorylation and enhances long-term memory in rodents (10.7554/eLife.00498). Here we show by genome-wide in vivo ribosome profiling that translation of a restricted subset of mRNAs is induced upon ISR activation. ISRIB substantially reversed the translational effects elicited by phosphorylation of eIF2α and induced no major changes in translation or mRNA levels in unstressed cells. eIF2α phosphorylation-induced stress granule (SG) formation was blocked by ISRIB. Strikingly, ISRIB addition to stressed cells with pre-formed SGs induced their rapid disassembly, liberating mRNAs into the actively translating pool. Restoration of mRNA translation and modulation of SG dynamics may be an effective treatment of neurodegenerative diseases characterized by eIF2α phosphorylation, SG formation and cognitive loss. Ribosome profiling with paired RNA-seq
2015-02-27 | E-GEOD-65778 | biostudies-arrayexpress
Project description:The ubiquitin-proteasome system (UPS) has recently emerged as a major target for drug development in cancer therapy. The proteasome inhibitor bortezomib has clinical activity in multiple myeloma and mantle cell lymphoma. Here we report that Eeyarestatin I (EerI), a chemical inhibitor that blocks ER-associated protein degradation (ERAD), has anti-tumor and biologic activities similar to bortezomib, and can synergize with bortezomib. Like bortezomib, EerI-induced cytotoxicity requires the upregulation of the BH3 only pro-apoptotic protein NOXA. We further demonstrate that both EerI and bortezomib activate NOXA via an unanticipated mechanism that requires cooperation between two processes: First, these agents elicit an integrated stress response program at the ER to activate the CREB/ATF transcription factors ATF3 and ATF4. We show that ATF3 and ATF4 form a complex capable of binding to the NOXA promoter, which is required for NOXA activation. Second, EerI and bortezomib also block ubiquitination of histone H2A to relieve its inhibition on NOXA transcription. Our results identify a class of anti-cancer agents that integrate ER stress response with an epigenetic mechanism to induce cell death. Experiment Overall Design: 1. EerI 10 vs 0 Experiment Overall Design: 2. EerI 10 vs 0 Experiment Overall Design: 3. Bzm 10 vs 0 Experiment Overall Design: 4. Bzm 10 vs 0
2009-02-28 | E-GEOD-14003 | biostudies-arrayexpress
Project description:This experiment is designed to evaluate gene expression alterations following treatment with gambogic acid and bortezomib in human HepG2 cells. We find gambogic acid yielded a similar gene expression profile as did bortezomib. Total RNA were extracted from human HepG2 cancer cells treated with gambogic acid (0.25μM, 0.5μM, 0.75μM) or bortezomib (50nM) for 9hr. HepG2 cells treated with vehicle alone was used as a control.
2012-06-14 | E-GEOD-38730 | biostudies-arrayexpress
Project description:We recently identified ISRIB as a potent inhibitor of the integrated stress response (ISR). ISRIB renders cells resistant to the effects of eIF2α phosphorylation and enhances long-term memory in rodents (10.7554/eLife.00498). Here we show by genome-wide in vivo ribosome profiling that translation of a restricted subset of mRNAs is induced upon ISR activation. ISRIB substantially reversed the translational effects elicited by phosphorylation of eIF2α and induced no major changes in translation or mRNA levels in unstressed cells. eIF2α phosphorylation-induced stress granule (SG) formation was blocked by ISRIB. Strikingly, ISRIB addition to stressed cells with pre-formed SGs induced their rapid disassembly, liberating mRNAs into the actively translating pool. Restoration of mRNA translation and modulation of SG dynamics may be an effective treatment of neurodegenerative diseases characterized by eIF2α phosphorylation, SG formation and cognitive loss.
2015-02-27 | GSE65778 | GEO
Project description:This experiment is designed to evaluate gene expression alterations following treatment with gambogic acid and bortezomib in human HepG2 cells. We find gambogic acid yielded a similar gene expression profile as did bortezomib.
2012-06-15 | GSE38730 | GEO