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Lack of Muc1-regulated beta-catenin stability results in aberrant expansion of CD11b+Gr1+ myeloid-derived suppressor cells from the bone marrow.

ABSTRACT: Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of myeloid cells that inhibit T-cell activity and contribute to the immune suppression characteristic of most tumors. We discovered that bone marrow (BM) progenitor cells from the Muc1 knockout (KO) mice differentiated into CD11b(+)Gr1(+) MDSCs in vitro under granulocyte macrophage colony-stimulating factor and interleukin-4 signaling. MUC1 is a tumor-associated mucin and its cytoplasmic tail (MUC1-CT) can regulate beta-catenin to promote oncogenesis. Given the importance of beta-catenin in hematopoiesis, we hypothesized that the MUC1 regulation of beta-catenin is important for MDSC development. Our current study shows that the aberrant development of BM progenitors into CD11b(+)Gr1(+) MDSCs is dependent on the down-regulation of beta-catenin levels that occurs in the absence of Muc1. In light of this, KO mice showed enhanced EL4 tumor growth and were able to better tolerate allogeneic BM185 tumor growth, with an accumulation of CD11b(+)Gr1(+) cells in the blood and tumor-draining lymph nodes. WT mice were able to similarly tolerate allogeneic tumor growth when they were injected with CD11b(+)Gr1(+) cells from tumor-bearing KO mice, suggesting that tolerance of allogeneic tumors is dependent on MDSC-mediated immune suppression. This further delineates the ability of Muc1 to control MDSC development, which could directly affect tumorigenesis. Knowledge of the biology by which Muc1 regulates the development of myeloid progenitors into MDSCs would also be very useful in enhancing the efficacy of cancer vaccines in the face of tumor immune suppression.

SUBMITTER: Poh TW

PROVIDER: S-EPMC2705196 | biostudies-literature | 2009 Apr

REPOSITORIES: biostudies-literature

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Lack of Muc1-regulated beta-catenin stability results in aberrant expansion of CD11b+Gr1+ myeloid-derived suppressor cells from the bone marrow.

Poh Tze Wei TW Bradley Judy M JM Mukherjee Pinku P Gendler Sandra J SJ

Cancer research 20090407 8

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of myeloid cells that inhibit T-cell activity and contribute to the immune suppression characteristic of most tumors. We discovered that bone marrow (BM) progenitor cells from the Muc1 knockout (KO) mice differentiated into CD11b(+)Gr1(+) MDSCs in vitro under granulocyte macrophage colony-stimulating factor and interleukin-4 signaling. MUC1 is a tumor-associated mucin and its cytoplasmic tail (MUC1-CT) can regulate beta-cate ...[more]

PMID: 19351842

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Project description:ObjectiveImmature CD11b + Gr1+ myeloid cells that acquire immunosuppressive capability, also known as myeloid-derived suppressor cells (MDSCs), are a heterogeneous population of cells that regulate immune responses. Our study's objective was to elucidate the role of ovarian cancer microenvironment in regulating the immunosuppressive function of CD11b+Gr1+ myeloid cells.MethodsAll studies were performed using the intraperitoneal ID8 syngeneic epithelial ovarian cancer mouse model. Myeloid cell depletion and immunotherapy were carried out using anti-Gr1 mAb, gemcitabine treatments, and/or anti-PD1 mAb. The treatment effect was assessed by a survival curve, in situ luciferase-guided imaging, and histopathologic evaluation. Adoptive transfer assays were carried out between congenic CD45.2 and CD45.1 mice. Immune surface and intracellular markers were assessed by flow cytometry. ELISA, western blot, and RT-PCR techniques were employed to assess the protein and RNA expression of various markers. Bone marrow-derived myeloid cells were used for ex-vivo studies.ResultsThe depletion of Gr1+ immunosuppressive myeloid cells alone and in combination with anti-PD1 immunotherapy inhibited ovarian cancer growth. In addition to the adoptive transfer studies, these findings validate the role of immunosuppressive CD11b+Gr1+ myeloid cells in promoting ovarian cancer. Mechanistic investigations showed that ID8 tumor cells and their microenvironments produced recruitment and regulatory factors for immunosuppressive CD11b+Gr1+ myeloid cells. CD11b+Gr1+ myeloid cells primed by ID8 tumors showed increased immunosuppressive marker expression and acquired an energetic metabolic phenotype promoted primarily by increased oxidative phosphorylation fueled by glutamine. Inhibiting the glutamine metabolic pathway reduced the increased oxidative phosphorylation and decreased immunosuppressive markers' expression and function. Dihydrolipoamide succinyl transferase (DLST), a subunit of α-KGDC in the TCA cycle, was found to be the most significantly elevated gene in tumor-primed myeloid cells. The inhibition of DLST reduced oxidative phosphorylation, immunosuppressive marker expression and function in myeloid cells.ConclusionOur study shows that the ovarian cancer microenvironment can regulate the metabolism and function of immunosuppressive CD11b + Gr1+ myeloid cells and modulate its immune microenvironment. Targeting glutamine metabolism via DLST in immunosuppressive myeloid cells decreased their activity, leading to a reduction in the immunosuppressive tumor microenvironment. Thus, targeting glutamine metabolism has the potential to enhance the success of immunotherapy in ovarian cancer.

Dataset Information

Lack of Muc1-regulated beta-catenin stability results in aberrant expansion of CD11b+Gr1+ myeloid-derived suppressor cells from the bone marrow.

Publications

Lack of Muc1-regulated beta-catenin stability results in aberrant expansion of CD11b+Gr1+ myeloid-derived suppressor cells from the bone marrow.

Similar Datasets

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