Project description:Immune-responsive gene 1 (IRG1) is a mitochondrial aconitate decarboxylase and can produce the immunomodulatory metabolite itaconic acid (ITA). However, its role in modulating the function of tumor-associated macrophages (TAMs) remains elusive. Here, we show that IRG1 is expressed in TAMs in human tumors and mouse models of cancer. Tumor cells induce Irg1 expression in macrophages which dampens the inflammatory response and restricts M1-like TAM polarization. In contrast, Irg1-deficent macrophages acquire more proinflammatory M1-like features, promote immunogenic antigen presentation, and enhance cytotoxic T cell infiltration into tumor sites. Consequently, Irg1 deficiency suppresses the growth of mouse syngeneic tumors, including melanoma, colorectal cancer, breast cancer, and pancreatic cancer. Irg1-deficient macrophages not only dictate the tumoricidal effect but enhance the efficacy of anti-PD(L)1 immunotherapy. In conclusion, our data identify IRG1 as a myeloid immune check point gene and foster the development of genetic or pharmacologic targeting of IRG1 for skewing macrophages toward an anti-tumor phenotype to treat a broad spectrum of cancer.
Project description:The presence of tumor-associated macrophages (TAMs) in the tumor microenvironment (TME) affects cancer progression and immunotherapy response. The RNA m6A methylation, an epigenetic modification, has recently been found to play a pivotal role in shaping the TME. However, the role and underlying mechanisms by which RNA m6A methylation regulates TAMs function and anti-tumor immunity remain elusive. Here we show that depletion of YTHDF2, a well-known m6A reader, in TAMs suppresses tumor growth and metastasis. Myeloid YTHDF2 deficiency reprograms TAMs to anti-tumorigenic type and increases their cross-presentation ability, thereby enhancing CD8+T cell-mediated anti-tumor immunity. Transcriptome-wide screening identifies YTHDF2 deficiency facilitates anti-tumorigenic TAMs reprogramming through targeting IFN-γSTAT1 signaling. Selectively targeting YTHDF2 in TAMs using toll-like receptor 9 agonist - conjugated small interfering RNA against YTHDF2 effectively promotes anti-tumor immunity, restrains tumor growth, and enhances the efficacy of anti-PD-L1 therapy. Together, our findings suggest that YTHDF2 in TAMs might be a promising therapeutic target for cancer immunotherapy.
Project description:Despite objective responses to PARP inhibition and improvements in progression-free survival compared to standard chemotherapy in patients with BRCA-associated triple-negative breast cancer (TNBC), benefits are transitory. Using high dimensional single-cell profiling of human TNBC, here we demonstrate that macrophages are the predominant infiltrating immune cell type in BRCA-associated TNBC. Through multi-omics profiling we show that PARP inhibitors enhance both anti- and pro-tumor features of macrophages through glucose and lipid metabolic reprogramming driven by the sterol regulatory element-binding protein 1 (SREBP-1) pathway. Combined PARP inhibitor therapy with CSF-1R blocking antibodies significantly enhanced innate and adaptive anti-tumor immunity and extends survival in BRCA-deficient tumors in vivo and is mediated by CD8+ T-cells. Collectively, our results uncover macrophage-mediated immune suppression as a liability of PARP inhibitor treatment and demonstrate combined PARP inhibition and macrophage targeting therapy induces a durable reprogramming of the tumor microenvironment, thus constituting a promising therapeutic strategy for TNBC.
Project description:The efficacy of immune checkpoint inhibitors (ICI) in hepatocellular carcinoma (HCC) treatment remains limited, warranting further investigation into the underlying mechanisms. Accumulating evidence indicates that myeloid cells within the tumor microenvironment (TME) play a role in immune evasion and treatment resistance. In this study, we aimed to explore the contribution of tumor-associated macrophages (TAMs) in the HCC TME. Our findings unveil the critical involvement of CX3C motif chemokine receptor 1 (CX3CR1)-positive TAMs in inducing T cell exhaustion through interleukin-27 (IL-27) secretion, providing valuable insights into the mechanisms underlying the suboptimal efficacy of anti-PD-1 therapy in HCC. Additionally, we identified prostaglandin E2 (PGE2) released by immune-attacked tumor cells as a key driver of CX3CR1+ TAM recruitment. To enhance the therapeutic response to current anti-PD-1 therapy, we propose a novel treatment strategy that combines targeted depletion of CX3CR1+ TAMs with anti-PD-1 therapy. Overall, our study contributes to the understanding of TAMs' role in cancer immunotherapy and presents potential clinical implications for HCC treatment. By targeting CX3CR1+ TAMs in conjunction with anti-PD-1 therapy, we have the potential to enhance the effectiveness of immunotherapeutic interventions in HCC patients.
Project description:The presence of tumor-associated macrophages (TAMs) in the tumor microenvironment (TME) affects cancer progression and immunotherapy response. The RNA m6A methylation, an epigenetic modification, has recently been found to play a pivotal role in shaping the TME. However, the role and underlying mechanisms by which RNA m6A methylation regulates TAMs function and anti-tumor immunity remain elusive. Here we show that depletion of YTHDF2, a well-known m6A reader, in TAMs suppresses tumor growth and metastasis. Myeloid YTHDF2 deficiency reprograms TAMs to anti-tumorigenic type and increases their cross-presentation ability, thereby enhancing CD8+T cell-mediated anti-tumor immunity. Transcriptome-wide screening identifies YTHDF2 deficiency facilitates anti-tumorigenic TAMs reprogramming through targeting IFN-γ-STAT1 signaling. Selectively targeting YTHDF2 in TAMs using toll-like receptor 9 agonist - conjugated small interfering RNA against YTHDF2 effectively promotes anti-tumor immunity, restrains tumor growth, and enhances the efficacy of anti-PD-L1 therapy. Together, our findings suggest that YTHDF2 in TAMs might be a promising therapeutic target for cancer immunotherapy.
Project description:Macrophages and neutrophils are almost invariably the most abundant intratumoral immune cells, and recent studies have revealed a sinister role for these cells in limiting chemotherapy efficacy. However, how these tumor-educated myeloid cells influence chemotherapy response is incompletely understood. Targeting tumor-associated macrophages by CSF-1 receptor (CSF-1R) blockade in a pre-clinical transgenic mouse model for breast cancer improved the anti-cancer efficacy of cisplatin. Importantly, our findings reveal that macrophage blockade in combination with cisplatin treatment evokes a compensatory neutrophil response limiting the therapeutic synergy of this therapy combination. Here we characterize neutrophils and macrophages gene expression profile from the tumor of mice treated with anti-CSF-1R, Control antibody, Cisplatin/anti-CSF-1R or cisplatin/control ab.