Project description:Polymorphonuclear myeloid-derived suppressor cell (PMN-MDSC), also named pathologically activated neutrophil, is a critical component of tumor microenvironment (TME), playing crucial roles in tumor progression and therapy resistance. CD300ld is specifically expressed in normal neutrophils and is upregulated in PMN-MDSCs upon tumor bearing. CD300ld knockout (KO) inhibits the development of multiple tumor types in a PMN-MDSC-dependent manner. Here, we compared the transcriptome of PMN-MDSCs from WT mice and CD300ld KO mice.
Project description:Polymorphonuclear myeloid-derived suppressor cell (PMN-MDSC) accumulate in maternal-fetal interface during pregnancy and play a role in maintenance of immune tolerance. Decreased PMN-MDSC is associated with pregnancy complications such as unexplained recurrent pregnancy loss (URPL). Whether PMN-MDSC function is different between normal pregnancy (NP) and URPL remains unexplored. Here we performed whole genome expression profile of 3 decidual PMN-MDSC from normal early pregnancy and 3 decidual PMN-MDSC from URPL. Total RNA were extracted. Cy5-labeled aRNA was hybridized and scanned on a G2505C Agilent Microarray Scanner with Agilent 0.1 XDR software. The gene expression pattern of the PMN-MDSC was significantly different between the NP group and the URPL group.
Project description:Polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC) inhibit immune responses in cancer, limit the effects of therapies and promote tumor cell metastasis. Here, we have identified a new precursor that differentiates into granulocytes in vitro and in vivo yet belong to the monocytic lineage. We have termed these cells monocyte-like precursors of granulocytes (MLPG). Under steady state conditions MLPG were absent in the spleen and barely detectable in the bone marrow (BM). In contrast, these cells significantly expanded in tumor-bearing mice. Selective depletion of monocytic cells had no effect on the number of granulocytes present in naïve mice but decreased the population of PMN-MDSC in tumor-bearing mice by 50%. The expansion of MLPG was found to be controlled by the down-regulation of the protein Rb1 and not the IRF8 transcription factor that is known to regulate the expansion of PMN-MDSC from classical granulocytes precursors. In cancer patients, putative MLPG were found within the population of CD15 CD14+HLA-DR-/lo M-MDSC. CXCR1+CD15 CD14+HLA-DR-/lo cells lacked immune suppressive activity but had potential to differentiate to neutrophils in contrast to monocytes and CXCR1- suppressive M-MDSC. These findings describe a mechanism of abnormal myelopoiesis in cancer and suggest potential new approaches for selective targeting of MDSC.
Project description:Polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC) inhibit immune responses in cancer, limit the effects of therapies and promote tumor cell metastasis. Here, we have identified a new precursor that differentiates into granulocytes in vitro and in vivo yet belong to the monocytic lineage. We have termed these cells monocyte-like precursors of granulocytes (MLPG). Under steady state conditions MLPG were absent in the spleen and barely detectable in the bone marrow (BM). In contrast, these cells significantly expanded in tumor-bearing mice. Selective depletion of monocytic cells had no effect on the number of granulocytes present in naïve mice but decreased the population of PMN-MDSC in tumor-bearing mice by 50%. The expansion of MLPG was found to be controlled by the down-regulation of the protein Rb1 and not the IRF8 transcription factor that is known to regulate the expansion of PMN-MDSC from classical granulocytes precursors. In cancer patients, putative MLPG were found within the population of CD15 CD14+HLA-DR-/lo M-MDSC. CXCR1+CD15 CD14+HLA-DR-/lo cells lacked immune suppressive activity but had potential to differentiate to neutrophils in contrast to monocytes and CXCR1- suppressive M-MDSC. These findings describe a mechanism of abnormal myelopoiesis in cancer and suggest potential new approaches for selective targeting of MDSC.
Project description:Polymorphonuclear myeloid-derived suppressor cell (PMN-MDSC), also named pathologically activated neutrophil, is a critical component of tumor microenvironment (TME), playing crucial roles in tumor progression and therapy resistance. Here, we compared the transcriptome of PMN-MDSCs from B16 tumor bearing mice and the neutrophils from tumor free mice.
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.
Project description:An immunosuppressive tumor microenvironment is one of the major obstacles to the efficacy of standard chemotherapies, such as doxorubicin, used to treat triple negative breast cancer (TNBC). Combination therapy may be a potential way to overcome this barrier. A nitric oxide (NO) donor such as glyceryl trinitrate (GTN) has shown beneficial effects in combination with standard chemotherapy/radiotherapy in patients with cancer. In this study, we investigated the combination of doxorubicin/GTN in a mouse model of TNBC. The results indicated that GTN significantly improved the anti-tumor efficacy of doxorubicin in mouse models of BC. Flow cytometry and immunohistochemistry analysis revealed that the GTN/doxorubicin combination increases the intra-tumor recruitment and activation of CD8+ lymphocytes that is associated with the ability of doxorubicin and doxorubicin/GTN to recruit and dampen the immunosuppressive function of PMN-MDSCs PD-L1low. Mechanistically, in PMN-MDSC, doxorubicin/GTN combination reduced STAT5 phosphorylation, while GTN +/- doxorubicin induced a ROS-dependent cleavage of STAT5 associated with a decrease of FATP2. Our results identify a new combination enhancing the immune-mediated anticancer therapy in a TNBC mouse model through a ROS-dependent reprograming of PMN-MDSCs towards a less immunosuppressive phenotype. These findings open up a new therapeutic perspective by combining GTN to doxorubicin for patients with TNBC.
Project description:It is suggested that decidual polymorphonuclear myeloid-derived suppressor cell (PMN-MDSCs) are a group of activated suppressive neutrophils. Decidual microenvironment can facilitate circulating neutrophils with phenotypes and functions of PMN-MDSCs. The mechanism of PMN-MDSCs differentiation induced by decidual microenvironment has not been fully understood. Here we performed whole genome expression profile of 3 decidual PMN-MDSCs and autologous neutrophils from normal early pregnancy. Total RNA were extracted. The arrays were scanned by the Agilent Scanner G2505C. There were differences of gene expression pattern between decidual PMN-MDSCs and autologous neutrophils in early normal pregnancy.
Project description:To identify the differences in the MDSC population in the tumor verus pre-metastatic niche site, we performed RNA sequencing of isolated CD11b+ Ly6G+ MDSCs and analyzed the differentially expressed genes in PMN-MDSCs isolated from MOC2 tumors and corresponding lung tissues from the same mice To compare the MDSC RNA-level expression with neutrophil expression, a public mouse neutrophil microarray dataset was used (GSE60336). Our MDSC RNA-seq and the public mouse neutrophil data sets were merged using COMBAT55. DEGs for three groups (MDSC lung, MDSC tumor and neutrophil) were calculated using SAM56 multiple class comparison with false discovery rate smaller than 0.05. A total of 5 samples were generated.
Project description:To comprehensively learn about the mechanisms of METTL3-mediated pro-tumoral functions, we performed RNA-sequencing to identify differentially expressed genes in isolated MDSC in Mettl3fl/fl (WT) and LysM-cre, Mettl3fl/fl (KO) MC38-bearing mice