Project description:Checkpoint inhibitors have revolutionized cancer treatment, but resistance remains a significant clinical challenge. Myeloid cells within the tumor microenvironment can modulate checkpoint resistance by either supporting or suppressing adaptive immune responses. Using an anti-PD-1 resistant mouse melanoma model, we show that targeting the myeloid compartment via CD40 activation and CSF1R blockade in combination with anti-PD-1 results in complete tumor regression in a majority of mice. This triple therapy combination is primarily CD40 agonist-driven in the first 24 hours post-therapy and shows a similar systemic cytokine profile in human patients as in mice. Functional single-cell cytokine secretion profiling of dendritic cells (DCs) using a novel microwell assay identified a CCL22+CCL5+ IL-12-secreting DC subset as important early-stage effectors of triple therapy. CD4+ and CD8+ T cells are both critical effectors of treatment, and systems analysis of single-cell RNA-sequencing data supports a role for DC-secreted IL-12 in priming T cell activation and recruitment. Finally, we show that treatment with a novel IL-12 mRNA therapeutic alone is sufficient to overcome PD-1 resistance and cause tumor regression. Overall, we conclude that combining myeloid-based innate immune activation and enhancement of adaptive immunity is a viable strategy to overcome anti-PD-1 resistance.
Project description:Checkpoint inhibitors have revolutionized cancer treatment, but resistance remains a significant clinical challenge. Myeloid cells within the tumor microenvironment can modulate checkpoint resistance by either supporting or suppressing adaptive immune responses. Using an anti-PD-1 resistant mouse melanoma model, we show that targeting the myeloid compartment via CD40 activation and CSF1R blockade in combination with anti-PD-1 results in complete tumor regression in a majority of mice. This triple therapy combination is primarily CD40 agonist-driven in the first 24 hours post-therapy and shows a similar systemic cytokine profile in human patients as in mice. Functional single-cell cytokine secretion profiling of dendritic cells (DCs) using a novel microwell assay identified a CCL22+CCL5+ IL-12-secreting DC subset as important early-stage effectors of triple therapy. CD4+ and CD8+ T cells are both critical effectors of treatment, and systems analysis of single-cell RNA-sequencing data supports a role for DC-secreted IL-12 in priming T cell activation and recruitment. Finally, we show that treatment with a novel IL-12 mRNA therapeutic alone is sufficient to overcome PD-1 resistance and cause tumor regression. Overall, we conclude that combining myeloid-based innate immune activation and enhancement of adaptive immunity is a viable strategy to overcome anti-PD-1 resistance.
Project description:Therapeutic use of agonistic anti-CD40 antibodies is a potentially powerful approach for activating the immune response to eradicate tumors. However, the translation of this approach to clinical practice has been significantly restricted due to the severe dose-limiting toxicities observed in multiple clinical trials. Here, we demonstrate that conventional type-1 dendritic cells are essential for triggering antitumor immunity but not toxicity by CD40 agonists, while macrophages, platelets, and monocytes lead to the toxic events. Therefore, we designed bispecific antibodies that target CD40 activation preferentially to dendritic cells. These bispecific reagents demonstrate a superior safety profile compared to their parental CD40 monospecific antibody, while triggering potent anti-tumor activity. We suggest such cell-selective bispecific agonistic antibodies as a drug platform to bypass the dose-limiting toxicities of anti-CD40, and of additional types of agonistic antibodies used for cancer immunotherapy.
Project description:CD40-stimulating immunotherapy elicits potent anti-tumor responses, which are mainly T-cell dependent. Here, we have investigated how tumor endothelial cells respond to CD40-stimulating immunotherapy by isolating endothelial cells from B16.F10 melanoma in anti-CD40 treated or isotype treated mice followed by RNA-sequencing. Gene set enrichment analysis revealed an increase in interferon- related responses in tumor endothelial cells following anti-CD40 therapy. The immunosuppressive enzyme indoleamine 2, 3-dioxygenase 1 (IDO1) was preferentially expressed in endothelial cells, and it was up-regulated upon anti-CD40 treatment. IDO1 expression in tumor endothelium was positively correlated to T-cell infiltration and to increased expression of IFNγ in the tumor microenvironment. In vitro, endothelial cells up-regulated IDO1 in response to T-cell-derived IFNγ, but not in response to CD40-stimulation. Combining agonistic anti-CD40 therapy with the IDO1 inhibitor epacadostat delayed tumor growth and increased survival in B16.F10 tumor-bearing mice, which was associated with increased activation of tumor-infiltrating T-cells. Hereby, we have uncovered an immunosuppressive feedback mechanism, in which tumor vessels limit the efficacy of cancer immunotherapy by up-regulating IDO1 in response to T-cell activation.
Project description:CD40 is expressed on a variety of antigen-presenting cells. Stimulation of CD40 results in inflammation by upregulation of other costimulatory molecules, increased antigen presentation, maturation (licensing) of dendritic cells, and activation of CD8+ T cells. Here we analyzed gene expression data from The Cancer Genome Atlas in melanoma, renal cell carcinoma, and pancreatic adenocarcinoma and found correlations between CD40 and several genes involved in antigen presentation and T cell function, supporting further exploration of CD40 agonists to treat cancer. Agonist CD40 antibodies have induced anti-tumor effects in several tumor models and the effect has been more pronounced when used in combination with other treatments (immune checkpoint inhibition, chemotherapy, and colony-stimulating factor 1 receptor inhibition). The reduction in tumor growth and ability to reprogram the tumor microenvironment in preclinical models lays the foundation for clinical development of agonistic CD40 antibodies (APX005M, ChiLob7/4, ADC-1013, SEA-CD40, selicrelumab, and CDX-1140) that are currently being evaluated in early phase clinical trials. In this article, we focus on CD40 expression and immunity in cancer, agonistic human CD40 antibodies, and their pre-clinical and clinical development. With the broad pro-inflammatory effects of CD40 and its ligand on dendritic cells and macrophages, and downstream B and T cell activation, agonists of this pathway may enhance the anti-tumor activity of other systemic therapies.
Project description:The thymus contains some B cells that are located at the corticomedullary junction. We found that these thymic B cells express and present the water channel protein AQP4 and are necessary and sufficient to mediate the negative selection of AQP4-reactive thymocytes. In order to express and present AQP4, thymic B cells need to be licensed through a CD40 signal. Here, we tested the significance of CD40 signaling in thymic B cells for the expression and presentation of distinct autoantigens (besides AQP4) to orchestrate thymocyte selection for these autoantigens.
Project description:Agonistic αCD40 therapy has been shown to inhibit cancer progression in only a fraction of patients. Understanding the cancer cell-intrinsic and microenvironmental determinants of αCD40 therapy response is therefore crucial to identify responsive patient populations and design efficient combinatorial treatments. Here, we show that the therapeutic efficacy of αCD40 in subcutaneous melanoma relies on pre-existing, type 1 classical dendritic cell (cDC1)-primed CD8+ T cells. However, after administration of αCD40, cDC1s were dispensable for anti-tumour efficacy. Instead, the abundance of activated cDCs, potentially derived from cDC2 cells, increased and further activated antitumour CD8+ T cells. Hence, distinct cDC subsets contributed to the induction of αCD40 responses. By contrast, lung carcinomas, characterized by a high abundance of macrophages, were resistant to αCD40 therapy. Combining αCD40 therapy with macrophage depletion led to tumour growth inhibition only in the presence of strong neoantigens. Accordingly, treatment with immunogenic cell death-inducing chemotherapy sensitized lung tumours to αCD40 therapy in subcutaneous and orthotopic settings. These insights into the microenvironmental regulators of response to αCD40 suggest that different tumour types would benefit from different combinations of therapies to optimize the clinical application of CD40 agonists.