Dabrafenib alters MDSC differentiation and function by activation of GCN2
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PROVIDER: PRJNA999590 | ENA |
REPOSITORIES: ENA
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Project description:The BRAF inhibitor dabrafenib has been reported to activate the integrated stress response (ISR) kinase GCN2, and the therapeutic effect has been partially attributed to GCN2 activation. Since ISR signaling is a key component of myeloid-derived suppressor cell (MDSC) development and function, we measured the effect of dabrafenib on MDSC differentiation and suppressive activity. Our data showed that dabrafenib attenuated MDSC ability to suppress T cell activity, which was associated with a GCN2-dependent block of the transition from monocytic progenitor to polymorphonuclear (PMN)-MDSCs and proliferative arrest resulting in PMN-MDSC loss. Transcriptional profiling revealed that dabrafenib-driven GCN2 activation altered metabolic features in MDSCs enhancing oxidative respiration, and attenuated transcriptional programs required for PMN development. Thus, ourdata reveals transcriptional networks that govern MDSC developmental programs, and the impact of GCN2 stress signaling on the innate immune landscape in tumors, providing novel insight into potentially beneficial off target effects of dabrafenib.
2024-03-20 | GSE239496 | GEO
Project description:The effect of targeted therapeutics on anticancer immune responses is poorly understood. The BRAF inhibitor dabrafenib has been reported to activate the integrated stress response (ISR) kinase GCN2, and the therapeutic effect has been partially attributed to GCN2 activation. Because ISR signaling is a key component of myeloid-derived suppressor cell (MDSC) development and function, we measured the effect of dabrafenib on MDSC differentiation and suppressive activity. Our data showed that dabrafenib attenuated MDSC ability to suppress T-cell activity, which was associated with a GCN2-dependent block of the transition from monocytic progenitor to polymorphonuclear (PMN)-MDSCs and proliferative arrest resulting in PMN-MDSC loss. Transcriptional profiling revealed that dabrafenib-driven GCN2 activation altered metabolic features in MDSCs enhancing oxidative respiration, and attenuated transcriptional programs required for PMN development. Moreover, we observed a broad downregulation of transcriptional networks associated with PMN developmental pathways, and increased activity of transcriptional regulons driven by Atf5, Mafg, and Zbtb7a. This transcriptional program alteration underlies the basis for PMN-MDSC developmental arrest, skewing immature MDSC development toward monocytic lineage cells. In vivo, we observed a pronounced reduction in PMN-MDSCs in dabrafenib-treated tumor-bearing mice suggesting that dabrafenib impacts MDSC populations systemically and locally, in the tumor immune infiltrate. Thus, our data reveal transcriptional networks that govern MDSC developmental programs, and the impact of GCN2 stress signaling on the innate immune landscape in tumors, providing novel insight into potentially beneficial off-target effects of dabrafenib.SignificanceAn important, but poorly understood, aspect of targeted therapeutics for cancer is the effect on antitumor immune responses. This article shows that off-target effects of dabrafenib activating the kinase GCN2 impact MDSC development and function reducing PMN-MDSCs in vitro and in vivo. This has important implications for our understanding of how this BRAF inhibitor impacts tumor growth and provides novel therapeutic target and combination possibilities.
| S-EPMC10936428 | biostudies-literature
Project description:GCN2 drives macrophage and MDSC function and immunosuppression in the tumor microenvironment
| PRJNA588058 | ENA
Project description:The purpose of our study was to examine the role of GCN2 in the function of immunosuppressive cells such as tumor associated macrophages and MDSCs. We show that a myeloid lineage specific deletion of GCN2 results in a shift towards a more proinflammatory phenotype of tumor associated macrophages and MDSCs, thereby promoting anti-tumor immunity.
2020-03-10 | GSE140028 | GEO
Project description:The purpose of our study was to examine the role of GCN2 in the function of immunosuppressive cells such as tumor associated macrophages and MDSCs. We show that a myeloid lineage specific deletion of GCN2 results in a shift towards a more proinflammatory phenotype of tumor associated macrophages and MDSCs, thereby promoting anti-tumor immunity.
2020-03-10 | GSE140026 | GEO
Project description:GCN2 drives macrophage and MDSC function and immunosuppression in the tumor microenvironment [ChIP-Seq]
| PRJNA588059 | ENA
Project description:GCN2 drives macrophage and MDSC function and immunosuppression in the tumor microenvironment [RNA-Seq]
| PRJNA588060 | ENA
Project description:Myeloid-derived suppressor cells (MDSC) represent a heterogeneous population of immature myeloid cells that accumulate in blood, liver, spleen and tumors upon chronic inflammation and tumor development in patients and mice. Acute hepatitis is characterized by a fast infiltration of inflammatory cells in the liver and increased enzymatic activity at this organ that could lead into liver fibrosis and cirrhosis. We have studied the biology of hepatic MDSC in acute hepatitis. Unexpectedly, hepatic MDSC, which accumulate in the liver of mice bearing subcutaneous tumors, failed to suppress inflammatory responses upon Con A injection, but instead were responsible for exacerbating acute liver damage. Phenotypic, genetic and functional studies demonstrated rapid changes of hepatic MDSC from a suppressor phenotype into a pro-inflammatory subset as early as 3 hours after Con A injection. An increase in the expression of pro-inflammatory cytokines, costimulatory molecules such as CD80, CD86 and CD40 along with a loss of suppressor function was noticed in mice upon Con A treatment. These changes were CD40-dependent and not found in CD40-/- MDSC. Interestingly, CD40 ligation of human MDSC in vitro resulted in down-regulation of arginase I expression and suppressor function. Finally, blockade of ROS production in hepatic MDSC ameliorated hepatocyte damage suggesting that MDSC mediated toxicity was ROS dependent. We believe that these findings reflect how MDSC plasticity can be modulated to promote inflammation, opening a new path for therapies targeting innate suppressive cells in cancer patients. EL4 tumors were established in C57BL/6 mice, then mice were injected either with PBS (n=3) or 12.5mg/kg Con A (n=3). Three hours later mice were sacrificed, liver CD11b+Gr-1+ cells were sorted and samples were processed for gene expression analysis.
2015-09-01 | E-GEOD-50949 | biostudies-arrayexpress
Project description:In response to different cellular stressors, the ISR kinases, PERK, PKR, HRI and GCN2, activate downstream transcriptional programs. While the core ISR transcription program is well characterized, markers that are specific to each individual ISR kinase activation pathway are not known. To identify markers that are induced by PERK or GCN2, but not the other ISR kinases, we subjected WT, GCN2-/-, and PERK-/- MEFs to amino acid starvation (RPMI 1640 SILAC -Lys -Arg) or Thapsigargin (200nM) treatment for 6 hours to activate the GCN2 and PERK pathways, respectively and performed RNA sequencing.
2022-07-01 | GSE179559 | GEO
Project description:Myeloid derived suppressor cells (MDSC) playing the immune suppressive roles in tumor bearing host consists of two major subsets of granulocytic and monocytic cells. Granulocytic MDSC (G-MDSC) express CD11b+ Gr-1high Ly6G+ Ly6Clow and produce high level of reactive oxygen species (ROS). Interestingly, neutrophils are well known ROS producing cells during immune defensive process and share same surface markers with G-MDSC. These similar features always brought the fundamental questions what’s the difference between G-MDSC and neutrophils but it’s not yet proven clearly. In this study, we examined the gene expression of G-MDSC and neutrophils using Affymetrix microarray G-MDSC (CD11b+Ly6G+Ly6Clow) were purifed from splenocytes in EL4 lymphoma tumor bearing mice by positive selection of Ly6G using microbeads isolation. Neutrophils were purified from ascitic fluids induced after injection of milk protein, casein by negative selection of F4/80 and positive selection of Ly6G using microbeads isolation. Their RNA was extracted and gene expression was analyzed using Affymetrix microarray.
2011-03-10 | E-GEOD-24102 | biostudies-arrayexpress