Intratumoral immunotherapy with anti-PD-1 and TLR9 agonist induces systemic antitumor immunity without accelerating rejection of cardiac allografts.
Anti-PD-1 和 TLR9 激动剂的瘤内免疫治疗诱导全身抗肿瘤免疫，而不加速心脏同种异体移植物的排斥反应。
- 作者列表："Dang N","Waer M","Sprangers B","Lin Y
:Immune checkpoint inhibitors, such as PD-1 blockades, have revolutionized the field of cancer immunotherapy. However, there is a growing concern whether PD-1 inhibitors can be safely administered to transplant recipients with advanced cancer as the T cells activated by checkpoint inhibitors may become reactive not only towards tumor antigens but also towards donor alloantigen resulting in allograft rejection. Here, immunotherapy with anti-PD-1/TLR9 agonist was administered to C57BL/6 mice bearing a cardiac allograft receiving maintenance immunosuppression or a PI4KIIIβ inhibitors-based tolerogenic regimen. Intratumoral (i.t.), but not systemic, immunotherapy promoted potent anti-tumor responses, but did not accelerated allograft rejection. This effect was associated with a pro-immunogenic effect induced by i.t. immunotherapy resulting in systemic cellular and humoral immune anti-tumor responses. Furthermore, when the tumor and cardiac allograft shared MHC antigens, i.t. immunotherapy promoted immune responses directed against tumor and the cardiac allograft resulting in allograft rejection. The anti-tumor effect was compromised by maintenance immunosuppression with cyclosporine A, indicating that an optimal balance between enhanced anti-tumor immunity and decreased transplant immunoreactivity is critical. A clinically relevant approach could be to temporary withdrawal maintenance immunosuppression and/or replace it by a PI4KIIIβ inhibitors-based tolerance inducing regimen to allow for effective immunotherapy to take place.
: 免疫检查点抑制剂，如 PD-1 封锁，彻底改变了癌症免疫治疗领域。然而,由于检查点抑制剂激活的 T 细胞不仅对肿瘤抗原具有反应性，而且对供体同种抗原也具有反应性，因此人们越来越担心 PD-1 抑制剂是否可以安全地用于晚期癌症的移植受者。在同种异体移植排斥反应中。这里，将 anti-PD-1/TLR9 激动剂免疫治疗给予 C57BL/6 小鼠移植心脏，接受维持免疫抑制或基于 pi4kiii β 抑制剂的耐受性方案。瘤内 (i.t.)，但不是全身的，免疫治疗促进了强效的抗肿瘤反应，但没有加速同种异体排斥反应。该效应与 i.t.诱导的促免疫原性效应相关。免疫治疗导致全身细胞和体液免疫抗肿瘤反应。此外，当肿瘤和心脏移植物共享 MHC 抗原时，i.t.免疫治疗促进了针对肿瘤和心脏同种异体移植物的免疫反应，导致同种异体移植物排斥。环孢素a 维持免疫抑制降低了抗肿瘤作用，表明增强抗肿瘤免疫和降低移植免疫反应性之间的最佳平衡至关重要。临床相关的方法可以是暂时停药维持免疫抑制和/或用基于 pi4kiii β 抑制剂的耐受诱导方案替代，以允许进行有效的免疫治疗。
METHODS::Macrophages (MΦ) play a critical role in tumor growth, immunosuppression and inhibition of adaptive immune responses in cancer. Hence, targeting signaling pathways in MΦs that promote tumor immunosuppression will provide therapeutic benefit. PI3Kγ has been recently established by our group and others as a novel immuno-oncology target. Herein, we report that a macrophage Syk-PI3K axis drives polarization of immunosuppressive MΦs which establish an immunosuppressive tumor microenvironment in in vivo syngeneic tumor models. Genetic or pharmacological inhibition of Syk and/or PI3Kγ in MΦs promotes a pro-inflammatory MΦphenotype, restores CD8+ T cell activity, destabilizes HIF under hypoxia, and stimulates an antitumor immune response. Assay for Transposase-accessible Chromatin using Sequencing (ATAC-seq) analyses on the bone marrow derived macrophages (BMDMs) show that inhibition of Syk kinase promotes activation and binding of NF-κB motif in SykMC-KO BMDMs, thus stimulating immunostimulatory transcriptional programming in MΦs to suppress tumor growth. Finally, we have developed in silico the "first in class" dual Syk/PI3K inhibitor, SRX3207, for the combinatorial inhibition of Syk and PI3K in one small molecule. This chemotype demonstrates efficacy in multiple tumor models and represents a novel combinatorial approach to activate antitumor immunity.
METHODS::Dysfunction of invariant natural killer T (iNKT) cells in tumor microenvironment hinders their anti-tumor efficacy, and the underlying mechanisms remain unclear. Here we report that iNKT cells increase lipid biosynthesis after activation, and that is promoted by PPARγ and PLZF synergically through enhancing transcription of Srebf1. Among those lipids, cholesterol is required for the optimal IFN-γ production from iNKT cells. Lactic acid in tumor microenvironment reduces expression of PPARγ in intratumoral iNKT cells and consequently diminishes their cholesterol synthesis and IFN-γ production. Importantly, PPARγ agonist pioglitazone, a thiazolidinedione drug for type 2 diabetes, successfully restores IFN-γ production in tumor-infiltrating iNKT cells from both human patients and mouse models. Combination of pioglitazone and alpha-galactosylceramide treatments significantly enhances iNKT cell-mediated anti-tumor immune responses and prolongs survival of tumor-bearing mice. Our studies provide a strategy to augment the anti-tumor efficacy of iNKT cell-based immunotherapies via promoting their lipid biosynthesis.
METHODS::Near-infrared photoimmunotherapy (NIR-PIT) is a newly developed and selective cancer treatment that induces necrotic and immunogenic cell death and utilizes a monoclonal antibody conjugated to a photo-absorber dye, IR700DX, activated by NIR light. Although CD44 is surface cancer marker associated with drug resistance, anti-CD44-IR700 NIR-PIT results in inhibited cell growth and prolonged survival in multiple tumor types. Meanwhile, anti-CD25-IR700-targeted NIR-PIT has been reported to achieve selective and local depletion of FOXP3+CD25+CD4+ regulatory T cells (Tregs), which are primary immunosuppressive cells in the tumor microenvironment (TME), resulting in activation of local antitumor immunity. Combined NIR-PIT with CD44- and CD25-targeted agents has the potential to directly eliminate tumor cells and also amplify the immune response by removing FOXP3+CD25+CD4+ Tregs from the TME. We investigated the difference in therapeutic effects of CD44-targeted NIR-PIT alone, CD25-targeted NIR-PIT alone, and the combination of CD44- and CD25-targeted NIR-PIT in several syngeneic tumor models, including MC38-luc, LL/2, and MOC1. The combined NIR-PIT showed significant tumor growth inhibition and prolonged survival compared with CD44-targeted NIR-PIT alone in all tumor models and showed prolonged survival compared with CD25-targeted NIR-PIT alone in MC38-luc and LL/2 tumors. Combined CD44/CD25 NIR-PIT also resulted in some complete remissions, whereas this was not achieved with either type of NIR-PIT alone. Therefore, combined NIR-PIT simultaneously targeting cancer antigens and immunosuppressive cells in the TME may be more effective than either type of NIR-PIT alone and may have potential to induce prolonged immune responses in treated tumors.