Effects of targeting endothelial mTORC1 on metastatic tumor cells
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE256508 | GEO | 2024/04/01
REPOSITORIES: GEO
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Project description:Tumor metastasis, the main cause of death in cancer patients, requires outgrowth of tumor cells after their dissemination and residence in microscopic niches. Nutrient sufficiency is a determinant of such outgrowth. Fatty acids (FA) can be metabolized by cancer cells for their energetic and anabolic needs, thereby supporting metastatic progression. The vascular endothelium serves as a barrier to access of molecules into tissues, but it is unclear how fatty acid delivery to early metastatic tumors is regulated. Using a mouse model of metastatic outgrowth in the lung, we show that tumor endothelium actively promotes tumor growth by transferring FA into developing metastatic tumors. Tumor burden was significantly reduced upon endothelial-specific targeted deletion of Raptor, a unique component of the mTORC1 complex (RptorECKO). The goal of this study was to investigate how targeting Raptor/mTORC1 impacts endothelial cells.
2024-04-01 | GSE256509 | GEO
Project description:Naïve T cells respond to antigen stimulation by exiting from quiescence into clonal expansion and functional differentiation, but the control mechanism is elusive. Here we describe that Raptor/mTORC1-dependent metabolic reprogramming is a central determinant of this transitional process. Loss of Raptor abrogates T cell priming and Th2 cell differentiation, although Raptor function is less important for continuous proliferation of actively cycling cells. mTORC1 coordinates multiple metabolic programs in T cells including glycolysis, lipid synthesis and oxidative phosphorylation to mediate antigen-triggered exit from quiescence. mTORC1 further links glucose metabolism to the initiation of Th2 differentiation by orchestrating cytokine receptor expression and cytokine responsiveness. Activation of Raptor/mTORC1 integrates T cell receptor (TCR) and CD28 co-stimulatory signals in antigen-stimulated T cells. Our studies identify a Raptor/mTORC1-dependent pathway linking signal-dependent metabolic reprogramming to quiescence exit, and this in turn coordinates lymphocyte activation and fate decisions in adaptive immunity. We used microarrays to explore the gene expression profiles differentially expressed in CD4+ T-cells from wild-type (WT) and CD4(cre) x Raptor(fl/fl) mice before and after stimulation with anti CD3/CD28 antibodies.
2014-01-27 | E-GEOD-51668 | biostudies-arrayexpress
Project description:The mechanistic target of rapamycin mTORC1 is a key regulator of cell metabolism and autophagy. Despite widespread clinical use of mTOR inhibitors, the role of mTORC1 in renal tubular function and kidney homeostasis remains elusive. By utilizing constitutive and inducible deletion of conditional Raptor alleles in renal tubular epithelial cells, we discovered that mTORC1 deficiency caused a marked concentrating defect, loss of tubular cells and slowly progressive renal fibrosis. Transcriptional profiling revealed that mTORC1 maintains renal tubular homeostasis by controlling mitochondrial metabolism and biogenesis as well as transcellular transport processes involved in counter-current multiplication and urine concentration. Although mTORC2 partially compensated the loss of mTORC1, exposure to ischemia and reperfusion injury exaggerated the tubular damage in mTORC1-deficient mice, and caused pronounced apoptosis, diminished proliferation rates and delayed recovery. These findings identify mTORC1 as an essential regulator of tubular energy metabolism and as a crucial component of ischemic stress responses. Pharmacological inhibition of mTORC1 likely affects tubular homeostasis, and may be particularly deleterious if the kidney is exposed to acute injury. Furthermore, the combined inhibition of mTORC1 and mTORC2 may increase the susceptibility to renal damage. Raptor fl/fl*KspCre and Raptor fl/fl animals were sacrificed at P14 before the development of an overt functional phenotype. Kidneys were split in half and immediately snap frozen in liquid nitrogen.
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Project description:Blood vessels are continually exposed to circulating lipids and elevations of ApoB containing lipoproteins cause atherosclerosis. Lipoprotein metabolism is highly regulated by lipolysis, largely at the level of the capillary endothelium lining metabolically active tissues. How large blood vessels, the site of atherosclerotic vascular disease, regulate the flux of fatty acids (FA) into triglyceride (TG) rich lipid droplets (LD) is not known. Here, we show that deletion of the enzyme, adipose triglyceride lipase (ATGL) in the endothelium, leads to neutral lipid accumulation in vessels and impairs endothelial dependent vascular tone and nitric oxide synthesis to promote endothelial dysfunction. Mechanistically, the loss of ATGL leads to endoplasmic reticulum stress-induced inflammation, thereby promoting EC dysfunction. Consistent with this mechanism, deletion of endothelial ATGL markedly increases lesion size in a model of atherosclerosis. Together, these data demonstrate that the dynamics of FA flux through LD impacts EC homeostasis and consequently large vessel function during normal physiology and in a chronic disease state
2023-10-31 | GSE246138 | GEO
Project description:Blood vessels are continually exposed to circulating lipids and elevations of ApoB containing lipoproteins cause atherosclerosis. Lipoprotein metabolism is highly regulated by lipolysis, largely at the level of the capillary endothelium lining metabolically active tissues. How large blood vessels, the site of atherosclerotic vascular disease, regulate the flux of fatty acids (FA) into triglyceride (TG) rich lipid droplets (LD) is not known. Here, we show that deletion of the enzyme, adipose triglyceride lipase (ATGL) in the endothelium, leads to neutral lipid accumulation in vessels and impairs endothelial dependent vascular tone and nitric oxide synthesis to promote endothelial dysfunction. Mechanistically, the loss of ATGL leads to endoplasmic reticulum stress-induced inflammation, thereby promoting EC dysfunction. Consistent with this mechanism, deletion of endothelial ATGL markedly increases lesion size in a model of atherosclerosis. Together, these data demonstrate that the dynamics of FA flux through LD impacts EC homeostasis and consequently large vessel function during normal physiology and in a chronic disease state
2023-12-07 | GSE246083 | GEO
Project description:We investigated the role of mTORC1 in murine hematopoiesis by conditionally deleting the Raptor gene in murine hematopoietic stem cells. We observed mutliple alterations evoked by Raptor loss in hematopoiesis and profiled gene-expression alterations induced by raptor loss in Flt3-Lin-Sca1+cKit+ hematopoietic stem and progenitor enriched cell populations, 5 weeks post Raptor deletion. Flt3-Lin-Sca1+cKit+ cells were flow sorted from mice containing homozygous floxed alleles for exon 6 of the Raptor gene in the presence (MT group) or absence (WT group) of the MxCre transgene, which was induced with injections of mice with pIpC 5 weeks before cell isolation.
2012-09-19 | E-GEOD-32265 | biostudies-arrayexpress
Project description:Naïve T cells respond to antigen stimulation by exiting from quiescence into clonal expansion and functional differentiation, but the control mechanism is elusive. Here we describe that Raptor/mTORC1-dependent metabolic reprogramming is a central determinant of this transitional process. Loss of Raptor abrogates T cell priming and Th2 cell differentiation, although Raptor function is less important for continuous proliferation of actively cycling cells. mTORC1 coordinates multiple metabolic programs in T cells including glycolysis, lipid synthesis and oxidative phosphorylation to mediate antigen-triggered exit from quiescence. mTORC1 further links glucose metabolism to the initiation of Th2 differentiation by orchestrating cytokine receptor expression and cytokine responsiveness. Activation of Raptor/mTORC1 integrates T cell receptor (TCR) and CD28 co-stimulatory signals in antigen-stimulated T cells. Our studies identify a Raptor/mTORC1-dependent pathway linking signal-dependent metabolic reprogramming to quiescence exit, and this in turn coordinates lymphocyte activation and fate decisions in adaptive immunity.
2014-01-27 | GSE51668 | GEO
Project description:Metastasis is the primary cause of cancer-related mortality and the mechanistically least well understood step of the tumor progression cascade. Employing surgical preclinical metastasis models, we show here that small primary tumors reprogram the body’s vascular endothelium to alter systemic homeostasis and to condition the premetastatic niche for metastatic colonization. Endothelial cells thereby serve as an amplifier of tumor-induced instructive signals. The combined endothelial transcriptomic and serum proteomic screen identified the TGFß pathway signaling specifier LRG1 as an early vascular niche instructor of metastatic colonization. Adjuvant LRG1 inhibition to primary tumor-resected mice delayed metastatic growth and increased overall survival. The study has thereby established the premetastatic systems map of primary tumor-induced vascular changes and identified LRG1 as a therapeutic target for metastasis
2022-05-16 | PXD013978 | Pride
Project description:The mechanistic target of rapamycin (mTOR) pathway integrates diverse environmental inputs, including immune signals and metabolic cues, to direct T cell fate decisions1. Activation of mTOR, comprised of mTORC1 and mTORC2 complexes, delivers an obligatory signal for proper activation and differentiation of effector CD4+ T cells2,3, whereas in the regulatory T cell (Treg) compartment, the Akt-mTOR axis is widely acknowledged as a crucial negative regulator of Treg de novo differentiation4-8 and population expansion9. However, whether mTOR signaling affects the homeostasis and function of Tregs remains largely unexplored. Here we show that mTORC1 signaling is a pivotal positive determinant of Treg function. Tregs have elevated steady-state mTORC1 activity compared to naïve T cells. Signals via T cell receptor (TCR) and IL-2 provide major inputs for mTORC1 activation, which in turn programs suppressive function of Tregs. Disruption of mTORC1 through Treg-specific deletion of the essential component Raptor leads to a profound loss of Treg suppressive activity in vivo and development of a fatal early-onset inflammatory disorder. Mechanistically, Raptor/mTORC1 signaling in Tregs promotes cholesterol/lipid metabolism, with the mevalonate pathway particularly important for coordinating Treg proliferation and upregulation of suppressive molecules CTLA-4 and ICOS to establish Treg functional competency. In contrast, mTORC1 does not directly impact the expression of Foxp3 or anti- and pro-inflammatory cytokines in Tregs, suggesting a non-conventional mechanism for Treg functional regulation. Lastly, we provide evidence that mTORC1 maintains Treg function partly through inhibiting the mTORC2 pathway. Our results demonstrate that mTORC1 acts as a fundamental ‘rheostat’ in Tregs to link immunological signals from TCR and IL-2 to lipogenic pathways and functional fitness, and highlight a central role of metabolic programming of Treg suppressive activity in immune homeostasis and tolerance. We used microarrays to explore the gene expression profiles differentially expressed in regulatory T-cells from wild-type and CD4(cre) x Raptor(fl/fl) mice
2013-06-24 | E-GEOD-46693 | biostudies-arrayexpress
Project description:Metastasis is a major cause of mortality, and remains a final frontier in the search for a cure for cancer. While there has been much research on the ‘seed’ (metastatic tumor cells) and the ‘soil’ (colonized host tissue), interactions between metastatic cancer cells and stromal endothelial cells, which occur at multiple stages during metastasis, are less well understood. Here we report a dynamic regulation of the endothelium by cancer cells through the formation of nanoscale intercellular membrane bridges, which act as physical conduits for intercellular communication in vitro and in vivo, including horizontal transfer of microRNAs (miRNA). The communication between the tumor cell and the endothelium upregulates markers associated with pathological endothelium, which is reversed by pharmacological inhibition of these nanoscale conduits. These results lead us to define the notion of “metastatic hijack”: cancer cell-induced transformation of healthy endothelium into pathological endothelium via horizontal communication through the nanoscale conduits. Pharmacological perturbation of these nanoscale membrane bridges decreases metastatic foci in syngeneic- and human xenograft-breast cancer models. Targeting the formation of these nanoscale membrane bridges may potentially emerge as a new therapeutic opportunity in the management of metastatic cancer. A miRNA microarray was used to evaluate the transport of endogenous microRNAs. The intercellular transfer-ve and intercellular transfer+ve samples were sorted from the same endothelial cell population with the only difference being the occurrence of intercellular transport. The heat map shows potential miRNA candidates for exogenous transfer on two independent biological replicates. These miRNA candidates were significantly up-regulated in the cells receiving transfer of intercellular contents. HUVECs that were not exposed to cancer cells were used as a baseline control.
2015-09-04 | E-GEOD-72679 | biostudies-arrayexpress