治疗性纳米疫苗使 EBV 相关肿瘤对检查点阻断治疗敏感。
- 作者列表："Liu H","Chen H","Liu Z","Le Z","Nie T","Qiao D","Su Y","Mai H","Chen Y","Liu L
:For successful treatment of EBV-associated tumors immune tolerance must be broken. While most studies of EBV-associated tumor vaccines have focused on augmenting tumor-specific effector T cells, the effects of these vaccines on the immune-suppressive tumor microenvironment have not been investigated. Here, we describe the manufacture of a nanovaccine using tannic acid (TA) and a newly constructed protein antigen for EBV-associated tumors with interferon-α (IFN-α) or CpG as adjuvants. TA as a biocompatible material from plant self-assembles with antigens and adjuvants via hydrogen bonding to form well-defined nanoparticulate vaccines by flash nanocomplexation, a scalable yet controllable technique. By targeting lymph nodes, the nanovaccine co-loaded with CpG adjuvant induces strong immune activation and exhibits efficient inhibition tumorigenesis. Moreover, the nanovaccine combining with anti-PD-L1 results a marked decrease in tumor size and prolonged survival of tumor-bearing mice by decreasing infiltration of regulatory T cells to the tumor lesion. This suggests that the nanovaccine can reverse immune checkpoint inhibitor resistance by remodeling the tumor microenvironment. Thus, this study shows a promising strategy for treatment of EBV-positive tumors in patients.
: 为了成功治疗 EBV 相关肿瘤，必须打破免疫耐受。虽然大多数 EBV 相关肿瘤疫苗的研究都集中在增强肿瘤特异性效应 T 细胞，但这些疫苗对免疫抑制性肿瘤微环境的影响尚未得到研究。在这里，我们描述了使用单宁酸 (TA) 和一种新构建的用于 EBV 相关肿瘤的蛋白抗原，以干扰素-α (IFN-α) 或 CpG 作为佐剂的纳米疫苗的制造。TA 作为一种生物相容性材料，来自植物通过氢键与抗原和佐剂自组装，通过 flash 纳米络合形成明确的纳米疫苗，这是一种可扩展但可控的技术。通过靶向淋巴结，与 CpG 佐剂共负载的纳米疫苗诱导强烈的免疫激活，并表现出有效的抑制肿瘤发生。此外，纳米疫苗联合 anti-PD-L1 通过减少调节性 T 细胞对肿瘤病灶的浸润，使肿瘤体积明显减小，荷瘤小鼠的生存期延长。这表明纳米疫苗可以通过重塑肿瘤微环境来逆转免疫检查点抑制剂的抵抗。因此，这项研究显示了一个有前途的策略，用于治疗 EBV 阳性肿瘤的患者。
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.