Mechanisms of cancer immunotherapy-associated thrombosis

癌症免疫疗法是几十年来癌症治疗中最重要的进展之一，并且已经迅速地发展。 转移到许多癌症的一线治疗。癌症免疫治疗的机制是使正常的 通过施用免疫检查点抑制剂（ICI），其是单克隆的， 针对包括PD-1、PD-L1和CTLA-4在内的关键免疫调节蛋白的抗体。禁用这些 途径增强抗肿瘤免疫力。然而，由于这些反应不是肿瘤特异性的，ICI是 与多种免疫相关不良事件（irAE）相关。我们和其他人最近报道了一个 在接受ICI治疗的患者中，血栓形成的发生率很高，可能超过20%;考虑到越来越多地使用 ICI在癌症治疗和癌症诊断中的频率，很明显ICI-癌症相关 血栓形成（ICI-CAT）已成为一个主要的临床问题， 迫切需要。然而，关于国际刑事法院-《禁止酷刑公约》机制的资料很少， 没有发表的研究解决这个问题。我们推测ICI-CAT是由ICI诱导的 在潜在的肿瘤相关炎症的情况下的细胞活化和促血栓形成活性。我们 小鼠模型表明，ICI-CAT需要存在潜在的肿瘤， ICI治疗后出现肿瘤细胞组织因子（TF）表达。我们的模型还支持以下角色： ICI-CAT中的中性粒细胞胞外陷阱（NET）和血小板活化; 通过我们证明的循环血小板-中性粒细胞聚集体水平升高，证实了ICI治疗的患者。 在细胞水平上，抗PD-1抗体刺激嗜中性粒细胞NET释放和促血栓形成活性，并且可能 在凝血酶浓度低于阈值的情况下也能增强血小板活化。在本申请中，我们 我建议使用细胞和动物模型来促进我们对ICI-CAT的理解，并扩展这些模型。 研究中使用了ICI治疗前后患者的临床样本。在目标1中，我们将确定 不同ICI和ICI组合对荷瘤小鼠血栓形成的影响，并评估 我们的模型使用其他肿瘤类型和小鼠品系。我们将检查血栓的大小和成分， 通过消耗小鼠的T细胞、嗜中性粒细胞、单核细胞或 血小板我们还将进一步确定参与血栓形成前活性表达的细胞机制。 使用来自正常人供体的分离的白细胞、混合的白细胞群和内皮细胞， 用细胞因子和ICI孵育。在目标2中，我们将通过测量 在开始ICI之前和之后，通过比较患者血浆中的炎症和血管活化， 接受ICI治疗的患者的骨髓细胞中促凝血基因的表达， 血栓形成总而言之，这些研究应该提供重要的新信息，从而更好地 了解ICI-CAT的机制，以及预防和治疗ICI-CAT的潜在新方法。

Cancer immunotherapy is one of the most important advances in cancer treatment in decades, and has rapidly moved to front-line therapy for many cancers. The mechanism of cancer immunotherapy is to disable normal immunoregulatory pathways through administration of Immune Checkpoint Inhibitors (ICI), which are monoclonal antibodies directed toward key immune regulatory proteins including PD-1, PD-L1 and CTLA-4. Disabling these pathways enhances anti-tumor immunity. However, since these responses are not tumor-specific, ICIs are associated with a variety of immune-related adverse events (irAEs). We and others have recently reported a high incidence of thrombosis, which may exceed 20%, in patients treated with ICI; given the increasing use of ICIs in cancer treatment and the frequency of cancer diagnoses, it is clear that ICI-Cancer Associated Thrombosis (ICI-CAT) has become a major clinical problem and that better understanding of this disorder is urgently needed. However, there is little information available concerning mechanisms of ICI-CAT, and there are no published studies addressing this issue. We hypothesize that ICI-CAT is an irAE resulting from ICI-induced cellular activation and prothrombotic activity in the setting of underlying tumor-associated inflammation. Our murine model demonstrates that ICI-CAT requires the presence of an underlying tumor, with markedly increased expression of tumor cell tissue factor (TF) occurring after ICI treatment. Our model also supports a role for neutrophil extracellular traps (NETs) and platelet activation in ICI-CAT; platelet activation is also suggested in patients treated with ICI by our demonstration of increased levels of circulating platelet-neutrophil aggregates. On a cellular level, anti-PD-1 antibodies stimulate neutrophil NET release and prothrombotic activity, and may also enhance platelet activation in the presence of subthreshold thrombin concentrations. In this application, we propose to advance our understanding of ICI-CAT using both cellular and animal models, and to extend these studies to clinical samples from patients before and after initiating treatment with ICI. In Aim 1, we will determine the effect of different ICI and ICI combinations on the development of thrombi in tumor-bearing mice, and assess our model using other tumor types and mouse strains. We will examine thrombus size and composition, and identify critical cell types involved in thrombus formation by depleting mice of T cells, neutrophils, monocytes or platelets. We will also further define the cellular mechanisms involved in expression of prothrombotic activity using isolated leukocytes from normal human donors, mixed leukocyte populations, and endothelial cells, incubated with cytokines and ICI. In Aim 2, we will extend these studies by measuring mechanistic markers of inflammation and vascular activation in patient plasma before and after initiating ICI, and by comparing procoagulant gene expression in myeloid cells from patients treated with ICI who did, or did not develop thrombosis. Taken together, these studies should provide important new information leading to better understanding of mechanisms, and potentially new approaches for prevention and treatment of ICI-CAT.