Attenuation of EIF4E Translation Initiation Adversely Affects Multiple Myeloma Cells
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE27897 | GEO | 2011/03/11
SECONDARY ACCESSION(S): PRJNA138205
REPOSITORIES: GEO
Similar Datasets
Project description:This work explores the therapeutic potential for the translation initiation factor eIF4E in multiple myeloma (MM). We show that targeting eIF4E is deleterious to MM cells and causes reduction of targets with established importance to the disease progression. We demonstrate that eIF4E inhibition may be achieved by treating the MM cells with the already clinically employed anti-viral drug Ribavirin. Results indicate that tetraspanin overexpression in MM cell lines increased global protein synthesis; CD81N1/CD82N1 also caused a decrease in peIF4E, its regulators and targets; direct inhibition of eIF4E (siRNA, Ribavirin) deleteriously affected MM cell lines; and Ribavirin attenuated viability and induced death of primary BM MM cells. Multiple Myeloma cell lines RPMI 8226 and CAG were each transiently transfected with purified plasmids of tetraspanins: pEGFP-N1 (N1, control), CD81N1-eGFP (81N1) or CD82N1-eGFP (82N1) (Clontech). Transfected cells were separated by Sorter Flow Cytometer 24 hours after transfection. Total RNA was extracted from sorted transfected cells with the Qiagen kit. Three separate experiments were analyzed by Whole Genome Affymetrix microarray chips (N1, 81N1, 82N1 in each cell line).
2011-03-11 | E-GEOD-27897 | biostudies-arrayexpress
Project description:Accumulating data indicate translation plays a role in cancer biology, particularly its rate limiting stage of initiation. Despite this evolving recognition, the function and importance of specific translation initiation factors is unresolved. The eukaryotic translation initiation complex eIF4F consists of eIF4E and eIF4G at a 1:1 ratio. Although it is expected that they display interdependent functions, several publications suggest independent mechanisms. This study is the first to directly assess the relative contribution of eIF4F components to the expressed cellular proteome, transcription factors, microRNAs, and phenotype in a malignancy known for extensive protein synthesis- multiple myeloma (MM). Previously, we have shown that eIF4E/eIF4GI attenuation (siRNA/ Avastin) deleteriously affected MM cells' fate and reduced levels of eIF4E/eIF4GI established targets. Here, we demonstrated that eIF4E/eIF4GI indeed have individual influences on cell proteome. We used an objective, high throughput assay of mRNA microarrays to examine the significance of eIF4E/eIF4GI silencing to several cellular facets such as transcription factors, microRNAs and phenotype. We showed different imprints for eIF4E and eIF4GI in all assayed aspects. These results promote our understanding of the relative contribution and importance of eIF4E and eIF4GI to the malignant phenotype and shed light on their function in eIF4F translation initiation complex. This study concentrated on a particular cancer model and studied the role of eIF4E and eIF4GI in the design of the cells' proteome. We used an unbiased, high throughput system to evaluate the individual importance of eIF4E and eIF4GI levels in MM. We used models of eIF4E or eIF4GI knocked down (KD) MM cell line RPMI 8226 and profiled their respective translated transcription factors (TF), often tumor suppressors or oncogenes. Furthermore, we assessed the KDs' microRNAs repertoires and cells' phenotype. Significant differences were observed between eIF4E and eIF4GI knockdown imprints.
2015-10-29 | E-GEOD-62821 | biostudies-arrayexpress
Project description:Accumulating data indicate translation plays a role in cancer biology, particularly its rate limiting stage of initiation. Despite this evolving recognition, the function and importance of specific translation initiation factors is unresolved. The eukaryotic translation initiation complex eIF4F consists of eIF4E and eIF4G at a 1:1 ratio. Although it is expected that they display interdependent functions, several publications suggest independent mechanisms. This study is the first to directly assess the relative contribution of eIF4F components to the expressed cellular proteome, transcription factors, microRNAs, and phenotype in a malignancy known for extensive protein synthesis- multiple myeloma (MM). Previously, we have shown that eIF4E/eIF4GI attenuation (siRNA/ Avastin) deleteriously affected MM cells' fate and reduced levels of eIF4E/eIF4GI established targets. Here, we demonstrated that eIF4E/eIF4GI indeed have individual influences on cell proteome. We used an objective, high throughput assay of mRNA microarrays to examine the significance of eIF4E/eIF4GI silencing to several cellular facets such as transcription factors, microRNAs and phenotype. We showed different imprints for eIF4E and eIF4GI in all assayed aspects. These results promote our understanding of the relative contribution and importance of eIF4E and eIF4GI to the malignant phenotype and shed light on their function in eIF4F translation initiation complex.
2015-10-29 | GSE62821 | GEO
Project description:Regulation of translation initiation is accomplished in diverse eukaryotes through proteins which bind to the mRNA cap-binding protein, eIF4E, and either prevent its association with eIF4G or form repressive mRNPs which exclude the translation machinery. Such mechanisms in plants, and even the presence of eIF4E-interacting proteins outside of eIF4G (and the plant-specific isoform eIFiso4G, which binds eIFiso4E) which operate in a gene regulatory manner are not known. Here we describe the Conserved Binding of eIF4E 1 (CBE1), a plant-specific protein with an evolutionarily conserved eIF4E binding motif. This protein binds eIF4E or eIFiso4E in vitro to form cap-binding complexes, and is found as a constituent of cap-binding complexes in vivo in an eIF4E-dependent manner. Mutants lacking CBE1 show dysregulation of cell cycle related transcripts, accumulating higher levels relative to wild-type plants of mRNAs encoding proteins involved in mitotic processes. These findings support CBE1 as a plant protein with the capability to form cap-binding complexes with the potential for gene regulatory activity.
2018-09-26 | GSE114363 | GEO
Project description:Cytoplasmic RNA bound to eIF4E was pulled down from MDA-MB-231 cells to determine the influence of radiation on eIF4E mRNA binding
2012-06-15 | GSE36179 | GEO
Project description:Cytoplasmic RNA bound to eIF4E was pulled down from MDA-MB-231 cells to determine the influence of radiation on eIF4E mRNA binding 4 samples were analyzed with 3 biological replicates
2012-06-14 | E-GEOD-36179 | biostudies-arrayexpress
Project description:Translational regulation plays a critical role in cell growth and proliferation, and its dysregulation results in cancer. Aberrant expression of the mRNA 5’cap-binding protein, eIF4E, has been implicated in cancer development and progression. eIF4E activity is promoted by phosphorylation. Here we show that “knock-in” mice in which eIF4E cannot be phosphorylated are resistant to tumorigenesis in a prostate cancer model. We identify multiple candidate genes involved in the resistance to oncogenic transformation. Importantly, phosphorylation of eIF4E is increased in hormone-refractory prostate cancer, the deadliest stage of the disease. Our results highlight eIF4E phosphorylation as a critical event in tumorigenesis. Comaparison of total RNA and polysomal RNA from mouse embryo fibroblasts derived from WT and eIF4E-KI (non phosphorylatable eIF4E) mice
2010-08-17 | E-GEOD-17451 | biostudies-arrayexpress
Project description:eIF4E, the major cap-binding protein, has long been considered limiting for translating the mammalian genome. However, the requirement for eIF4E dose at an organismal level remains unexplored. By generating an Eif4e haploinsufficient mouse, we surprisingly found that 50% reduction in eIF4E, while compatible with normal development and global protein synthesis, significantly impeded cellular transformation and tumorigenesis. Genome-wide translational profiling uncovered a translational program induced by oncogenic transformation and revealed a critical role for eIF4E dose specifically in translating a network of mRNAs enriched for a unique 5’UTR signature. In particular, we demonstrate that eIF4E dose is essential for translating mRNAs regulating reactive oxygen species (ROS) that fuel transformation and cancer cell survival in vivo. Therefore, mammalian cells have evolved surplus eIF4E levels that cancer cells hijack to drive a translational program supporting tumorigenesis Total cellular RNA and high MW polysome associated RNA were isolated from matched untransformed and transformed WT and Eif4e+/- MEFs for analysis on Affymetrix Mouse Gene 1.0 ST arrays. The difference in log2 RMA intensity between matched polysomal RNA and total RNA was taken to quantify translational efficiency (TE).
2015-07-01 | E-GEOD-68238 | biostudies-arrayexpress
Project description:Combining a genetic and pharmacological approach, we modulated eIF4E activity across its physiological activity range and identified subsets of genes whose translation was either hypo- or hyper- sensitive to eIF4E activity changes. eIF4E hypersensitive genes had longer 5'UTRs with higher GC content; and longer 3'UTRs with lower GC content and a higher density of unique microRNA target sites. Proliferation related genes were enriched among eIF4E hypersensitive genes; and consistent with this, decreasing eIF4E activity inhibited cell cycle transit. Our findings provide genome wide insights into the properties of mRNAs under translational control across the physiological range of eIF4E activity.
2015-12-31 | GSE56072 | GEO
Project description:Combining a genetic and pharmacological approach, we modulated eIF4E activity across its physiological activity range and identified subsets of genes whose translation was either hypo- or hyper- sensitive to eIF4E activity changes. eIF4E hypersensitive genes had longer 5'UTRs with higher GC content; and longer 3'UTRs with lower GC content and a higher density of unique microRNA target sites. Proliferation related genes were enriched among eIF4E hypersensitive genes; and consistent with this, decreasing eIF4E activity inhibited cell cycle transit. Our findings provide genome wide insights into the properties of mRNAs under translational control across the physiological range of eIF4E activity. NIH 3T3 derivatives genetically altered to induce eIF4E when treated with mifepristone and a non-inducible control NIH 3T3 derivative were cultured with or without treatment with mifepristone and varying doses of a pharmacological eIF4E inhibiting agent, 4Ei-1 (0 μM, 10 μM, 50 μM, 100 μM, 200 μM). Total RNA and polyribosome RNA were isolated after 4h of treatment. Three replicates of each experimental group were completed. In addition, three replicates of the inducible cell line treated with less potent analog to the inhibiting agent, 4Ei-4, were completed to probe for non-specific drug effects.
2015-12-31 | E-GEOD-56072 | biostudies-arrayexpress