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Project description:Phosphatidylinositol-3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway activation contributes to mantle cell lymphoma (MCL) pathogenesis and drug resistance. However, the use of mTOR inhibitors as single agents have shown limited clinical efficacy in relation with drug activation of feedback loops. Selective PI3K inhibition or dual PI3K/mTOR catalytic inhibition are different therapeutic approaches developed to achieve effective pathway blockage. Here, we evaluated the antitumor activity of a mTOR inhibitor, a pan-PI3K inhibitor and a dual PI3K/mTOR inhibitor in primary MCL cells. We found that dual PI3K/mTOR inhibitor modulated angiogenesis, tumor invasiveness and cytokine signaling compared to a mTOR inhibitor and a pan-PI3K inhibitor in MCL. We used microarrays to compare the effect of these three compounds in MCL and identified distinct classes of down-regulated genes modulated by each compound. Global RNA expression in primary cells from two MCL patients treated with a mTOR inhibitor, a pan-PI3K inhibitor and a dual PI3K/mTOR inhibitor for 8 hours
2013-12-14 | E-GEOD-53309 | biostudies-arrayexpress
Project description:mTOR and ERRα are key regulators of common metabolic processes. However, the extent of functional overlap between these two factors has not been investigated. ChIP-sequencing analyses on mouse liver reveal mTOR recruitment to regulatory regions of genes on a genome-wide scale including enrichment at genes shared with ERRα that are involved in the TCA cycle and lipogenesis pathway. A total of 9469 and 23226 peaks were identified for mTOR and ERRα ChIP-seq datasets, respectively. mTOR and ERRα mouse liver ChIP-seq datasets obtained from pooling 8 individual ChIPs from a chromatin pool of 26 livers.
2013-04-03 | E-GEOD-43638 | biostudies-arrayexpress
Project description:Emerging data suggest a significant cross-talk between metabolic and epigenetic programs. However, the relationship between the mechanistic target of rapamycin (mTOR) which is a pivotal regulator of cellular metabolism, and epigenetic modifications remains poorly understood. We thus explored the impact of modulating mTOR signaling on histone methylation, a well-known epigenetic modification. Our results show that constitutive mTORC1 activation caused by abrogation of TSC2 increases H3K27me3 but not H3K4me3 or H3K9me3, via 4E-BPs-mediated induction of EZH2 protein levels. Surprisingly, mTOR inhibition also induced H3K27me3 independently of TSC2. This coincided with reduced EZH2 and increased EZH1 protein levels. Notably, the ability of mTOR inhibitors to induce H3K27me3 levels was positively correlated with their anti-proliferative effects. Collectively, our findings demonstrate that both activation and inhibition of mTOR selectively increase H3K27me3 by distinct mechanisms, whereby the ability of mTOR inhibitors to induce H3K27me3 influences their anti-proliferative effects.
2023-11-02 | GSE246887 | GEO
Project description:To investigate the functional and mechanistic roles of mTOR in zebrafish larvae fin regeneration, we firstly examined the spatiotemporal expression of mTOR in larvae fin and established a mTOR knockout (mTOR-KO) transgenic fish line using CRISPER / Cas9 gene editing technology. Moreover, mTOR was essential for the activation of macrophages, which is a key factor in maintaining the regenerative repair process. We also demonstrated that mTOR knockdown attenuated the proliferative capacity of bud embryo cell during the regenerative phase, while cell apoptosis was not affected. RNA-sequence analysis showed changes in mitochondrial function and dnm1l was identified as the main regulatory factor during the fin regeneration stage. We further suggested that mTOR may promote mitochondrial fission to support bud embryo cell regeneration via CaM-mTOR-dnm1l axis.
2023-10-13 | GSE242949 | GEO
Project description:mTOR is an important anti-cancer target that integrates diverse signals to control protein synthesis and cell growth. Numerous studies by using mTOR inhibitors and/or gene deletion of mTOR negative regulators have implicated mTOR targeting in suppressing gene expression and cell proliferation. However, we found that gene targeting of mTOR in mouse hematopoietic stem cells (HSCs) results in a loss of quiescence and increased proliferation. Adaptive to mTOR loss, mTOR-/- HSCs increase chromatin access and activate global gene expression, in contrast to short-term inhibition by mTOR inhibitors. Such genomic changes are due to a compensatory activation of a MAPK/Mnk/eIF4E signaling pathway that enhances the translation of RNA pol-II and consequent c-myc expression. This adaptive mechanism can also be adopted by leukemia stem cells undergone long-term mTOR inhibitor treatment to confer resistant to mTOR targeting. Our studies provide new insights and a foregone strategy for overcoming drug resistance in mTOR targeted therapy.
2020-12-24 | GSE134317 | GEO
Project description:We have used ChIP-seq to profile binding of the estrogen receptor (ER) to chromatin in response to two mTOR inhibitors, i.e. everolimus (RAD001) and vistusertib (AZD2014). Two hours of treatment with these inhibitors significantly affected mTOR signaling, but surprisingly did not affect binding of ER to chromatin. This suggests that these mTOR inhibitors work through largely ER-independent mechanisms.
2018-04-06 | GSE103023 | GEO
Project description:To identify candidate mTOR-interacting molecules, we performed an anti-Flag immunoprecipitation (IP) followed by mass spectrometry (MS)-based proteomic analysis in 293T cells overexpressing Flag-tagged mTOR. We identified P4HA2 binding proteins with anti-HA IP followed by (MS)-based proteomic analysis in 293T cells overexpressing HA-tagged P4HA2. To speculate that mTOR can be hydroxylated by P4HA2. We used 293T cells overexpressing Flag-mTOR, Flag-mTOR/HA-P4HA2, and Flag-mTOR/HA-P4HA2-overexpressing cells treated with EDHB, we conducted an anti-Flag IP to capture and enrich mTOR protein, and the immunoprecipitates were subjected to MS analysis.
2023-04-14 | PXD041531 |
Project description:The mechanistic target of rapamycin (mTOR) is a central regulator of cell growth and an attractive anti-cancer target that integrates diverse signals to control cell proliferation. Previous studies using mTOR inhibitors have shown that mTOR targeting suppresses gene expression and cell proliferation. To date, however, mTOR targeted therapies in cancer have seen very limited efficacy, and one key issue is related to the development of evasive resistance. In this manuscript, through the use of a gene targeting mouse model, we have found that inducible deletion of mTOR in hematopoietic stem cells (HSCs) results in a loss of quiescence and increased proliferation. Adaptive to the mTOR loss, mTOR-/- HSCs increase chromatin accessibility and activate global gene expression, contrary to the effects of short-term inhibition by mTOR inhibitors. Mechanistically, such genomic changes are due to a rewiring and adaptive activation of the ERK/MNK/eIF4E signaling pathway that enhances the protein translation of RNA polymerase II (RNAP II), which in turn leads to increased c-Myc gene expression, allowing the HSCs to thrive despite loss of a functional mTOR pathway. This adaptive mechanism can also be utilized by leukemia cells undergoing long-term mTOR inhibitor treatment to confer resistance to mTOR drug targeting. The resistance can then be counteracted by MNK, CDK9, or c-Myc inhibition. These results provide new insights into the physiological role of mTOR in mammalian stem cell regulation and implicate a novel mechanism of evasive resistance in the context of mTOR targeting.
2020-12-24 | GSE134316 | GEO
Project description:The TSC/mTOR (tuberous sclerosis complex/mammalian target of rapamycin) pathway has a central role in cell growth and is involved in human tumorigenesis. Here, we demonstrate an unexpected role of TSC2 and mTOR in regulating key inflammatory cytokines in monocytes, macrophages, and dendritic cells after bacterial stimulation. mTOR deficiency promoted IL-12/IL-23 and blocked IL-10 production via the transcription factor NF-kB. Conversely, loss of TSC2, a key negative regulator of mTOR, led to reduced NF-kB activity, limited IL-12 but enhanced IL-10 production. Transcriptional profiling demonstrated that mTOR additionally regulated many mediators important for inflammation and immunoregulation including PD-L1, CCR5, CCL22, and MCP-1. mTOR inhibition in vivo rescued susceptible mice from a lethal Listeria monocytogenes infection by modulating IL-12/IL-10 production. These data identify the TSC2/mTOR pathway as a novel pathway in innate immune responses by controlling NF-kB with profound clinical implications for infectious diseases, cancer, or transplantation. Keywords: inflammatory response of monocytes to LPS and rapamycin 107 CD14+ monocytes from four different donors were stimulated with 100 ng/ml LPS with or without 100 nM rapamycin for 4 hours. Cells were harvested, washed and pelleted and frozen at â80° C. Sample preparation and hybridization to a PIQORTM Immunology Microarray Human Antisense (quadrupled cDNA fragments for 1070 genes) was performed at the Miltenyi Microarray Service Unit. In brief, RNA was extracted with the TRIzol method (Sigma-Aldrich) and 1mg of total RNA was linear amplified by T7 polymerase. Total RNA from the LPS treated cells were Cy3 labeled, LPS and rapamycin treated cells were Cy5 labeled; both samples of a donor were hybridized on a single microarray. Only genes with signal intensities >2-fold above average background in one of the two channels were regarded as expressed.
2010-05-19 | E-GEOD-6002 | biostudies-arrayexpress
Project description:mTOR is a serine/threonine kinase with a crucial role in regulating fundamental cellular processes and is an attractive anticancer target. Multiple clinical trials of mTOR kinase inhibitors such as AZD2014 that suppress both mTORC1 and mTORC2 are ongoing, but their specificity and toxicity features remain a concern. We have developed an inducible kinase-dead D2338A mTOR mouse knock-in model and show that it is useful to study the kinase-independent function of mTOR and for assessing the off-target effects of mTOR kinase inhibitors. We found that while the mTOR KI mice in hematopoietic system displayed similar phenotypes to that of mTOR KO mice, they have significantly prolonged survival time than the KO mice. Whereas AZD2014 was mostly on-target in suppressing mTOR kinase activity, mimicking that seen in KI stem cells in transcriptome analysis, off-target genes in KI cells induced by AZD2014 including Ahnak2, Emp1, Lilrb4, Tpsb2, and Cma1 were detected. Our studies reveal kinase-independent function of mTOR in hematopoiesis and presents a mouse model for precisely assessing specificity of mTOR kinase inhibitors. Stringent test of drugs with such mouse models in the preclinical setting may provide useful information guiding the safety and efficacy of related clinical trials.
2023-08-29 | GSE235097 | GEO