ChREBP-mediated choline deprivation and chemokine secretion shape TAMs to promote immune evasion
Ontology highlight
ABSTRACT: Tumor metabolic reprogramming has been recognized as a critical determinant in tumor development and cancer immunotherapy. Aberrant choline metabolism is emerging as a defining hallmark of cancer. However, its impact on antitumor immunity remains largely unclear. Carbohydrate responsive element binding protein (ChREBP)-mediated choline deprivation impels tumor-associated macrophages (TAMs) reprogramming and maintains an immunosuppressive tumor microenvironment (TME). Mechanistically, ChREBP interacts with SP1 to increase the expression of immunosuppressive chemokines CCL2 and CXCL1, as well as choline transporter SLC44A1. As such, high expression of CCL2 and CXCL1 expression promotes recruitment of TAMs and MDSCs in the TME. Tumor cells with high SLC44A1 expression compete consuming choline with M1-like TAMs, inhibiting cGAS-STING signaling and promoting the polarization of M1 to M2 macrophages. Clinically, ChREBP-SP1-choline metabolism axis expression is associated with poor clinical outcome in CRC. Inhibiting ChREBP reduces M2-like TAMs and MDSCs to enhance anti-tumor immunity, suggesting ChREBP as a potential immunotherapy target in cancer.
Project description:Tumor Associated Macrophages (TAMs) represent a critical immunological barrier to effective anti-tumor mechanisms of developing carcinomas of the oropharynx. Tumor infiltrating monocytes become activated and differentiate into TAMs which contribute to the immunological landscape of tumors as either containing or devoid of effector T-cells. We first compared transcriptional responses of normal and OPC derived monocytes from single individuals, at the single cell level, after exposure to media conditioned by SCC-25 and SCC-154 OPC cell lines. Since media conditioned by both SCC-154 and SCC-25 contain secreted IL1α, stimulation of these monocytes with recombinant IL1α was included as a control. We showed that to these conditioned media, CXCL1, CXCL5 and CCL2 transcripts reached higher levels in a greater proportion of OPC-patient monocytes compared to control monocytes. These early monocyte responses were validated in a cohort of isolated monocytes exposed to the same media. These findings represent that monocytes may be secreting TME influencing cytokines, prior to their own differentiation, which in turn recruit detrimental cell populations including T-regs, MDSCs and other monocytes.
Project description:Tumor-associated macrophages (TAMs) are key components of the tumor microenvironment (TME) which can either promote tumor progression (M2) or induce antitumor immunity (M1). The hypothesis of our study is that the expression of FOLR2 is associated with an M2-like macrophage profile. The main goal of this study is to compare the transcriptomic profile of FOLR2 positive and FOLR2 negative TAMs obtained from the ascites of C57BL/6 mice bearing ovarian ID8 intraperitoneal tumors. Abstract: The immunosuppressive tumor microenvironment (TME) represents a major barrier for effective immunotherapy. Tumor-associated macrophages (TAMs) are highly heterogeneous and plastic cell components of the TME which can either promote tumor progression (M2-like) or boost antitumor immunity (M1-like). Selective targeting of the pro-tumorigenic subset of TAMs represents an attractive therapeutic strategy. Here, we demonstrate that a subset of TAMs that expressing folate receptor β (FRβ) possess an immunosuppressive, tumor-promoting M2-like profile, while FRβ negative TAMs feature pro-inflammatory M1 macrophage properties. In syngeneic tumor mouse models, the administration of FRβ-targeted chimeric antigen receptor (CAR) T-cells mediated elimination of FRβ+ TAMs in the TME, which resulted in an enrichment of pro-inflammatory monocytes, an influx of endogenous tumor-specific CD8+ T-cells, delayed tumor progression, and prolonged survival. Preconditioning of the TME with FRβ-specific CAR T-cells also improved the effectiveness of tumor-directed anti-mesothelin CAR T-cells, while simultaneous co-administration of both CAR products did not. Thus, CAR T-cell-mediated depletion of immunosuppressive M2-like TAMs incites a pro-inflammatory TME that broadens endogenous antitumor immunity and limits tumor progression, highlighting the pro-tumor role of FRβ+ TAMs in the TME and the therapeutic implications of TAM-depleting agents as preparative adjuncts to conventional immunotherapies that directly target tumor antigens.
Project description:Tumor immunotherapy has been convincingly demonstrated as a feasible approach for treating cancers. Although promising, however, the immunosuppressive tumor microenvironment (TME) has been recognized as a major obstacle in tumor immunotherapy. It is highly desirable to release an immunosuppressive “brake” for improving cancer immunotherapy. Among tumor-infiltrated immune cells, tumor-associated macrophages (TAMs) play an important role in the growth, invasion and metastasis of tumors. The polarization of TAMs (M2) into the M1 type can alleviate the immunosuppression of the TME and enhance the effect of immunotherapy. Inspired by this, we constructed a therapeutic exosomal vaccine from antigen-stimulated M1-type macrophages (M1OVA-Exos). M1OVA-Exos are capable of polarizing TAMs into M1 type through downregulation of the Wnt signaling pathway. Mediating the TME further activates the immune response and inhibits tumor growth and metastasis via the exosomal vaccine. Our study provides a new strategy for the polarization of TAMs, which augments cancer vaccine therapy efficacy.
Project description:Tumor-associated macrophages (TAMs), including anti-tumor M1-like TAMs and pro-tumor M2-like TAMs, are transcriptionally dynamic innate immune cells with diverse roles in lung cancer development. Epigenetic regulators are key controllers of macrophage fate in the spatially heterogeneous tumor microenvironment. Here, we demonstrate that the spatial proximity of histone deacetylase 2 (HDAC2) – overexpressing M2-like macrophages to tumor cells significantly correlates with poor overall survival of lung cancer patients. Suppression of HDAC2 in TAMs altered macrophage polarization, migration, and associated signaling pathways related to interleukin, chemokine, cytokine, and T cell activation. In various co-culture systems of TAMs and cancer cells, suppressing HDAC2 in TAMs results in reduced proliferation and migration and increased apoptosis of cancer cell lines and primary lung cancer cells, as well as attenuated endothelial cell tube length. HDAC2 regulates the pro-tumor macrophage phenotype via acetylation of histone H3 and transcription factor SP1. Myeloidcell–specificc deletion of Hdac2 (Hdac2f/fLysmCre) and pharmacological inhibition of class I HDACs in four different murine lung cancer models (intravenous, intratracheal, tumor relapse, and KrasLA2-driven) induced M2-like to M1-like macrophage phenotypic switching, altered infiltration of CD4 and CD8 T cells and retarded tumor growth and tumor microenvironmental angiogenesis. ThuTAM-specific HDAC2 expression may provide a novel strategy for lung cancer stratification and therapy.
Project description:The main challenge for immune checkpoint blockade (ICB) therapy lies in immunosuppressive tumor microenvironment (TME). Repolarizing M2-like tumor-associated macrophages (TAMs) into inflammatory M1 phenotype is a promising strategy for cancer immunotherapy. Here, we found that the transmembrane protein SHISA3 is induced by DAMPs/PAMPs in macrophages via nuclear factor-κB (NF-κB) transcription factors, and SHISA3 forms complex with HSPA8 to reciprocally activates NF-κB signaling thus maintains M1 polarization of macrophages. Enforced expression of Shisa3 in TAMs increases their phagocytosis and antigen presentation abilities and promotes CD8+ T cell-mediated antitumor immunity. Local delivery of mRNA encoding Shisa3 enables therapy of cancer by dual effects on tumor cells and TAMs, and enhance the efficacy of PD-1 antibody. Taken together, our findings describe the role of SHISA3 in reprogramming TAMs that ameliorates cancer immunotherapy To find new molecules that regulate macrophage polarization, we performed transcriptomic analysis on early macrophages polarization induced by LPS for 0, 2, 4 hours.
Project description:Myeloid Derived Suppressor Cells (MDSCs) promote immunosuppressive activities in the tumor microenvironment (TME), resulting in increased tumor burden and diminishing the anti-tumor response of immunotherapies. While primary and metastatic tumors are typically the focal points of therapeutic development, the immune cells of the TME are uniquely programmed by the tissue of the metastatic site. In particular, MDSCs are programmed uniquely within different organs in the context of tumor progression. Given that MDSC plasticity is shaped by the surrounding environment, the proteome of MDSCs from different metastatic sites are hypothesized to be unique. A bottom-up proteomics approach using Sequential Window Acquisition of All Theoretical Mass Spectra (SWATH-MS) was used to quantify the proteome of CD11b+ cells derived from murine liver metastases (LM) and lung metastases (LuM). A comparative proteomics workflow was employed to compare MDSC proteins from LuM (LuM-MDSC) and LM (LM-MDSC) while also elucidating common signaling pathways, protein function, and possible drug-protein interactions.
Project description:Therapeutic combinations to alter solid tumor microenvironments (TME) in immunosuppressive tumors such as breast cancer are essential to improve their responses to immune checkpoint inhibitors (ICIs). Entinostat, an oral histone deacetylase inhibitor (HDACi), has been shown to improve responses to ICIs in various tumor models with immunosuppressive TMEs. The precise and comprehensive alterations to the TME induced by entinostat remain unknown. Here, we employ single-cell RNA-sequencing on HER2 overexpressing breast tumors from mice treated with entinostat and ICIs to characterize for the first time changes across all cell types within the TME. This analysis demonstrates that treatment with entinostat induces a shift from a pro-tumor to an anti-tumor TME signature characterized predominantly by changes in the myeloid cells. We confirm myeloid-derived suppressor cells (MDSCs) within entinostat-treated tumors are associated with a less suppressive G-MDSC phenotype and now demonstrate altered suppressive signaling involves the NFkB and STAT3 pathways. In addition to MDSCs, tumor-associated macrophages are epigenetically reprogrammed toward an anti-tumor M1-like phenotype likely contributing to a more sensitized TME. Overall, our in-depth analysis suggests entinostat-induced changes on multiple myeloid cell types reduce immunosuppression and increase mechanisms of an anti-tumor response that improve sensitivity to ICI. Sensitization of the TME by entinostat could ultimately broaden the population of patients with breast cancer who could derive benefit from ICIs.
Project description:The tumor microenvironment (TME) contains various immune-suppressive cells such as regulatory T cells (Tregs) and M2-like tumor associated macrophages (TAMs) that express the enzyme arginase I (Arg1). T helper 1-polarized Treg (Th1-Treg) is a Treg subset that markedly accumulate in tumor tissues, suppressing anti-tumor immunity. However, little is known about the mechanism behind the abundant presence of Th1-Tregs in TME. Here we show that Arg1-expressing TAMs (Arg1+ TAMs) play critical roles for the high Th1-Treg ratio in TME. Selective depletion of Arg1+ TAMs using the VeDTR system inhibited tumor growth and concurrently reduced the Th1-Treg ratio in TME. Notably, Arg1+ TAMs secreted platelet factor 4 (PF4) that polarized Tregs to Th1-Tregs in a CXCR3-dependent manner. Both genetic PF4 inactivation and PF4 neutralization hindered Th1-Treg accumulation in TME, consequently suppressing tumor growth. Collectively, our study highlights the importance of M2-like TAM-produced PF4 for high Th1-Treg levels in TME to suppress anti-tumor immunity, and demonstrates PF4 neutralization as a potential cancer immunotherapeutic strategy by intervening the M2-like TAM/Th1-Treg axis.
Project description:Immune checkpoint blockade therapy has been successfully applied in clinical settings as a standard therapy for many cancer types, but its clinical efficacy is restricted to patients with immunologically hot tumors. Various strategies to modify the tumor microenvironment (TME), such as Toll-like receptor (TLR) agonists, have been explored but have not been successful. Here, we identified a mechanism of acquired resistance to combination treatment consisting of an agonist for multiple TLRs, OK-432 (Picibanil), and PD-1 blockade. Adding the TLR agonist failed to convert the TME from immunogenically cold to hot. The combination treatment did not augment antitumor immunity, particularly CD8+ T cell responses, in multiple animal models. The failure was attributed to the coactivation of innate suppressive cells, such as CD11b+ Gr1+ Ly6C- Ly6G+ myeloid-derived suppressor cells (MDSCs) expressing CXCR2, through high CXCL1 production by macrophages in the TME upon OK-432 treatment. Thus, a triple combination treatment with OK-432, PD-1 blockade, and a CXCR2 neutralizing antibody overcame the resistance induced by MDSCs, resulting in a far stronger antitumor effect than that of any dual combination or single treatment. The accumulation of MDSCs was similarly observed in the pleural effusion of lung cancer patients after OK-432 administration. We propose that successful combination cancer immunotherapy stimulating innate immunity against immunologically cold tumors requires modulation of unwanted activation of innate immune suppressive cells, including MDSCs.