A dynamic mutational landscape associated to an inter-regionally diverse immune response in malignant rhabdoid tumour.
- 作者列表："Yasui H","Valind A","Karlsson J","Pietras C","Jansson C","Wille J","Romerius P","Backman T","Gisselsson D
:Malignant rhabdoid tumour (MRT) is a childhood neoplasm of high malignancy characterised by biallelic mutation and/or loss of the epigenetic master regulator SMARCB1, accompanied by no or few other oncogenic drivers. In spite of their generally low mutational burden, an intratumoural T cell response has been reported in a subset of MRTs, indicating that immune checkpoint inhibition may be considered a viable therapy option for some patients. We here assess the evolution over time and space of predicted neoantigens and indicators of immune checkpoint status in two MRT patients who progressed under treatment. Both patients showed an accumulation of novel clonal and subclonal mutations, including predicted neoantigens, in metastases compared to their inferred ancestral clones in the primary tumours. The first patient had peritoneal metastases from an MRT of the liver. Clonal deconvolution revealed polyclonal seeding from the primary tumour to a single metastatic site, followed by a local subclonal burst of mutations. The second patient had a renal MRT with multiple pulmonary metastases, each of which could be traced back to a single genetically unique founder cell, with formation of novel subclones in two metastases. Both patients showed a regionally heterogeneous landscape of predicted neoantigens and of tumour infiltrating lymphocytes expressing CD8 and PD1. In both patients, some tumour regions fulfilled established criteria for PD-L1 positivity (> 1% of tumour cells), while others did not. This suggest that even in a tumour type like MRT, with a single driver mutation, there can be heterogeneity in neoantigen repertoire, immune response and biomarkers for checkpoint blockade among sampled locations. This must be taken into account when assessing progressed MRT patients for checkpoint inhibition therapy. This article is protected by copyright. All rights reserved.
: 恶性横纹肌样瘤 (MRT) 是一种高度恶性的儿童肿瘤，以双等位基因突变和/或表观遗传主调控因子 SMARCB1 缺失为特征，伴有无或少数其他致癌驱动因子。尽管它们的突变负荷普遍较低，但在 mrt 的一个子集中报告了瘤内 T 细胞反应，表明免疫检查点抑制可能被认为是一些患者的可行治疗选择。我们在此评估了 2 例治疗进展的 MRT 患者预测的新抗原和免疫检查点状态指标随时间和空间的演变。与原发肿瘤中推断的祖先克隆相比，两例患者在转移中表现出新的克隆和亚克隆突变的积累，包括预测的新抗原。第一例患者从肝脏的 MRT 腹膜转移。克隆去卷积揭示了从原发肿瘤到单个转移部位的多克隆种植，随后是局部亚克隆突变爆发。第二例患者有一个肾脏 MRT，伴有多发性肺转移，每个病灶都可以追溯到一个单一的遗传独特的创始细胞，在两个转移瘤中形成新的亚克隆。两名患者都显示了预测的新抗原和表达 CD8 和 pd1 的肿瘤浸润淋巴细胞的区域异质性景观。在这两个患者中，一些肿瘤区域符合 PD-L1 阳性的既定标准 (> 1% 的肿瘤细胞)，而另一些则不符合。这表明，即使在像 MRT 这样的肿瘤类型中，在单个驱动突变的情况下，采样位置之间的新抗原库、免疫反应和检查点阻断的生物标志物也可能存在异质性。在评估进展的 MRT 患者进行检查点抑制治疗时，必须考虑到这一点。本文受版权保护。保留所有权利。
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.