Tyrosine Kinases and Thrombosis

项目摘要 酪氨酸激酶抑制剂（TKI）是治疗多种癌症的重要药物。但任何 药剂在功效与靶向或非靶向有害作用之间具有折衷。这一观点在以下方面变得明显： 治疗慢性粒细胞白血病（CML）时，有效和广泛抑制酪氨酸激酶 抑制剂泊那替尼（Iclusig，Ariad Pharmaceuticals，现为Takeda）被认为具有31%的 心血管（CV）事件，其中21%为显著不良事件（SAE）。在第二阶段试验中 4年时，动脉闭塞事件的发生率为26%（心肌梗死14%，卒中11%， 和肢体缺血11% -一些患者具有多于1个器官事件）。波纳替尼（波尼）是5种TKI之一 获批用于治疗CML 我们建立了一个小鼠模型，以检查TKI对凝血、血管和血小板的影响。 功能在稳态条件下接受各种TKI治疗的老年小鼠中，与伊马替尼不同， 显示动脉和静脉血栓形成的风险增加。波尼治疗导致动脉 阻塞时间，更大的静脉凝块，并产生过度活跃的血小板-有助于 血栓形成加剧我们的实验室已经确定了血栓形成前的关键机制， 波尼的表型。首先，poni治疗的小鼠血管壁活性氧（ROS）增加， 细胞凋亡和表达凝血因子V和VIII的炎性血管淋巴细胞浸润。 第二，poni处理的小鼠的血小板对胶原蛋白反应过度。此外，我们还有 发现吡格列酮（pio），一种过氧化物酶体增殖体激活物受体激动剂，当与波尼一起使用时，可以使血管壁正常化 炎症和血小板过度活化以纠正小鼠血栓形成风险 本申请的总体假设是poni相关血栓形成是由免疫细胞血管生成引起的。 炎症表达促血栓基因和改变的血小板信号传导导致血小板高反应性。 波尼治疗已经确定了血栓前血管功能障碍的一种新机制，通过这种机制， 浸润性淋巴细胞表达凝血酶FV和FVIII，可能有助于血栓形成。在 波尼在人的治疗剂量下抑制p-LynY 507，p-LynY 507是激活的GPVI的负调节剂，在两种未刺激的 而活化血小板对p-LynY 396和p-SykY 352几乎没有影响，这表明这些血小板可能是 更有反应性。事实上，poni治疗的小鼠的血小板对较低浓度的CRP有反应。这些 缺陷通过Pio的基因组和非基因组PPAR激动作用在遗传和功能上得到纠正。的 建议的具体目标如下： 该提案的具体目的如下：1）确定泊那替尼-和其他TKI-的作用机制。 诱导的血管炎症2）确定poni诱导的血小板过度活化的机制。 这些研究将确定波尼和其他TKI对血管壁和血小板的作用机制， 导致心血管事件。他们提出了poni相关血栓形成和纠正的临床前模型 一种过氧化物酶体增殖物激活物受体激动剂最后，它们将作为一般TKI CVD评估的范例。

Project Summary Tyrosine kinase inhibitors (TKIs) are important therapeutic agents to treat various cancers. However, any agent has a tradeoff between efficacy and on or off target deleterious effects. This notion became evident in the treatment of chronic myelogenous leukemia (CML) when a potent and broadly inhibitory tyrosine kinase inhibitor, ponatinib (Iclusig, Ariad Pharmaceuticals, now Takeda) was recognized to have a 31% incidence of cardiovascular (CV) events of which 21% overall were significant adverse events (SAEs). In a Phase II trial (PACE) at 4 yrs. the incidence of arterial occlusive events was 26% (myocardial infarction 14%, stroke 11%, and limb ischemia 11% - some patients have more than 1 organ event). Ponatinib (poni) is one of 5 TKIs approved for the treatment of CML We have created a murine model to examine the effects of TKIs on blood coagulation, vascular, and platelet function. In aged mice treated with the various TKIs under steady-state conditions, ponatinib, unlike imatinib, demonstrated an increased risk of arterial and venous thrombosis. Poni treatment leads to decreased arterial occlusion times, larger venous clots and generates hyperactive platelets - features that contribute to heightened thrombosis. Our laboratory has identified key mechanisms underlying the prothrombotic phenotype of poni. First, poni-treated mice have increased vessel wall reactive oxygen species (ROS), apoptosis, and inflammatory vascular lymphocyte infiltrates that expresses coagulation factors V and VIII. Second, platelets from poni-treated mice are hyperactive to in response to collagen. Additionally, we have determined that pioglitazone (pio), a PPAR agonist, when given with poni normalizes the vessel wall inflammation and platelet hyperactivity to correct murine thrombosis risk The overall hypothesis of this application is that poni-associated thrombosis results from immune cell vascular inflammation expressing prothrombotic genes and altered platelet signaling resulting in platelet hyperreactivity. Poni treatment has identified a novel mechanism of prothrombotic vascular dysfunction by which vascular infiltrating lymphocytes express coagulation enzymes FV and FVIII potentially to contribute to thrombosis. At therapeutic dosing in man, poni inhibits p-LynY507, a negative regulator of activated GPVI, in both unstimulated and activated platelets with little effect on p-LynY396 and p-SykY352, suggesting that these platelets may be more reactive. In fact, poni-treated mice have platelets that react to lower concentrations of CRP. These defects are genetically and functionally corrected by pio’s genomic and non-genomic PPAR agonism. The specific aims of the proposal are as follows: The specific aims of the proposal are as follows: 1) Determine the mechanism of ponatinib- and other TKI- induced vascular inflammation 2) Identify the mechanisms of poni-induced platelet hyperactivation. These studies will determine the mechanisms of poni and other TKI effects on vessel wall and platelets that lead to cardiovascular events. They present a pre-clinical model for poni-associated thrombosis and correction with pio, a PPAR agonist. Last, they will serve as a paradigm for CVD assessment for TKIs in general.