Project description:Immune checkpoint inhibition (ICI) has revolutionized treatment in cancers that are naturally immunogenic by enabling infiltration of T cells into the tumor microenvironment (TME) and promoting cytotoxic signaling pathways. Tumors possessing complex immunosuppressive TME’s such as breast and pancreatic cancers present unique therapeutic obstacles as response rates to ICI remain low. Such tumors often recruit myeloid-derived suppressor cells (MDSCs) whose functioning prohibits both T-cell activation and infiltration. We attempted to sensitize these tumors to ICI using epigenetic modulation to target MDSC trafficking and function to foster a less immunosuppressive TME. We showed that combining a histone deacetylase inhibitor, entinostat (ENT), with anti–PD-1, anti–CTLA-4, [A1] [A2] or both, significantly improved tumor-free survival in both the HER2/neu transgenic breast cancer and the Panc02 metastatic pancreatic cancer mouse models. Using flow cytometry, gene expression profiling, and ex vivo functional assays, we characterized populations of tumor-infiltrating lymphocytes (TILs) and MDSCs, as well as their functional capabilities. We showed that addition of ENT to checkpoint inhibition led to significantly decreased suppression by granulocytic-MDSCs in the TME of both tumor types. We also demonstrated an increase in activated granzyme-B–producing CD8+ T effector cells in mice treated with combination therapy. Gene expression profiling of both MDSCs and TILs identified significant changes in immune-related pathways. In summary, addition of ENT to ICI significantly altered infiltration and function of innate immune cells, allowing for a more robust adaptive immune response. These findings provide a rationale for combination therapy in patients with immune-resistant tumors, including breast and pancreatic cancers.
Project description:Murine MDSCs isolated from the spleens of Lewis lung carcinoma mice were treated with or without WGP, and then miRNA array was used to analyze the differentailly expressed miRNAs. Murine MDSCs were isolated from the spleens of Lewis lung carcinoma tumor-bearing mice, and the sorted MDSCs were stimulated with or without 100 µg/ml WGP for 24 h. Then, the total RNA was extracted to perform miRNA array to analyze the differentially expressed miRNAs in MDSCs treated with or without WGP
Project description:The macrolide rapamycin is known for its immunosuppressive properties since it inhibits mTOR (mammalian target of rapamycin), which activity affects differentiation and functions of various innate and adaptive immune cells involved in graft-versus-host disease development. Since rapamycin procures immunosuppressive effects on the immune response, rapamycin is an attractive candidate for graft-versus-host disease prevention after allogeneic bone marrow transplantation. Recently, an activating effect of rapamycin on the function of myeloid-derived suppressor cells (MDSCs), a subset of immune suppressive cells of myeloid origin was reported. However, the effect of rapamycin treatment on MDSCs induction and function in the management of graft-versus-host disease is largely unknown. We used an MHC class I and II mismatched parent into F1 bone marrow transplantation mouse model to elucidate the mechanisms of rapamycin on MDSCs in the context of graft-versus-host disease prevention. To define the impact of rapamycin therapy on MDSCs gene expression profile, we performed mircoarray analysis and compared gene expression profiles of ex vivo isolated MDSCs from rapamycin and PBS treated mice
Project description:The Aurora-A inhibitor alisertib shows encouraging activities in clinical trials against multiple malignances including advanced breast cancer. However, its mechanism of action remains unclear, especially regarding how the inflammatory microenvironment is involved in the efficacy of alisertib. Here, we demonstrated that Aurora-A inhibition directly reshapes the immune microenvironment through removal of tumor-promoting myeloid cells and enrichment of anti-cancer T lymphocytes, which restores a tumor-suppressive microenvironment and significantly contributes to the regression of murine mammary tumors. Mechanistically, the Aurora-A inhibitor effectively eliminated myeloid cells including myeloid-derived suppressor cells (MDSCs) and macrophages in tumors by triggering apoptosis of these cells. Further, Aurora-A inhibition could disrupt the immunosuppressive functions of MDSCs through inhibiting Stat3 mediated ROS production. These alterations led to significant increases in the proportion and the number of CD8+ and CD4+ T lymphocytes, which efficiently inhibited the proliferation of tumor cells. In summary, these data revealed that in addition to suppressing the proliferation of tumor cells, Aurora-A inhibitor directly modulates and restores an anti-tumor immune-microenvironment in breast cancer. Intriguingly, Aurora-A inactivation combined with PD-L1 blockade showed synergistic efficacy in the treatment of mammary tumors, providing an effective strategy for clinical trials of chemo-immunotherapy in breast cancer.
Project description:Myeloid-derived suppressor cells (MDSCs) are increased by tumor-derived factors and suppress anti-tumor immunity. MDSCs obtained at a late time point after tumor injection had stronger suppressive activity than MDSCs obtained at an early time point, as measured by T cell proliferation assays. To find factors in MDSCs that change during tumor growth, we analyzed gene expression profiles from MDSCs at different time points after tumor injection. We found that immune response-related genes were down-regulated, but pro-tumor function-related genes were up-regulated in both Mo-MDSCs and PMN-MDSCs at the late time point. Among differentially expressed genes, FK506 binding protein 51 (FKBP51), which is a member of the immunophilin protein family and plays a role in immunoregulation, was increased in the Mo- and PMN-MDSCs isolated from the late time points. Experiments using siRNA and a chemical inhibitor of FKBP51 revealed that FKBP51 contributes to the regulation of the suppressive function of MDSCs by increasing iNOS, ARG1, and ROS levels and enhancing NF-kappaB activity. Collectively, our data suggest that FKBP51 is a novel molecule that can be targeted to regulate the immunosuppressive function of MDSCs. To identify the factors that licensed MDSCs to be more suppressive as tumors grow, we analyzed gene expression profiles in the two subsets of MDSCs at different time points (3wks, 6wks) during tumor progression. CD11b+Ly-6C(high)Ly-6G(low) Mo-MDSCs and CD11b+Ly-6C(low)Ly-6G(high) PMN-MDSCs were sorted from pooled spleens of naïve mice and Her-2/CT26 tumor-bearing mice. Total RNA was purified and gene expression was analyzed by the Affymetrix GeneChip® Mouse Gene 1.0 ST Array.
Project description:Our data showed that ENT broadly impacted multiple populations of immune cells within the TME. Thus, we performed general immune transcriptome profiling on whole tumors isolated from the neu-N model using a PanCancer immune-profiling gene panel for the NanoString platform.
Project description:Myeloid-derived suppressor cells (MDSCs) as a population of myeloid cells enriched in cancer patients with immunosuppressive function. Further studies have determined that MDSCs are comprised of two groups: polymorphonuclear-MDSCs (G-MDSCs) and monocytic-MDSCs (M-MDSCs). We used a microbeads kit (Miltenyi) to isolate G-MDSCs and M-MDSCs with markers Ly6c2-Ly6g+CD11b+ and Ly6c2+Ly6g-CD11b+, respectively. And then using bulk RNA-seq to anlysis the enrichment gene expression in G-or M-MDSC which from wild type, APCmin mutant adenoma and immune deffiency mice.
Project description:Differentially expressed genes of CD11b+Gr-1+ immature myeloid cells (IMCs) in the bone marrow and colonic tumor setting of histidine decarboxylase (HDC)-KO mice were examined by microarray (Affymetrix Mouse 430.2 array). Myeloid differentiation-related candidate genes were sought to be isolated and functionally studied. Total RNA of HDC-expressing CD11b+Gr-1+ IMCs of bone marrow were extracted from HDC-EGFP and HDC-EGFP/HDC-KO mice (3 mice in each group). CD11b+Gr-1+ myeloid-derived suppressor cells (MDSCs) of colon tumor were sorted from 10-12 colon tumors of WT and HDC-KO mice (5 mice in each group), and pooled to extract total RNA for microarray studies. Two technical replicates for each of the four groups. Four sets of comparisons were performed to screen for upregulated or downregulated genes in the HDC-KO CD11b+Gr-1+ IMCs or MDSCs (experiment group) compared to the WT group: (1) HDC-expressing CD11b+Gr-1+ IMCs of bone marrow of HDC KO mice compared to bone marrow IMCs of WT mice; (2) CD11b+Gr-1+ MDSCs in tumors of HDC-KO mice compared to WT mice; (3) CD11b+Gr-1+ MDSCs of WT colon tumors compared to IMCs in the WT bone marrow; and (4) CD11b+Gr-1+ MDSCs of colon tumors of HDC-KO mice compared to IMCs in the bone marrow of HDC-KO mice.