Tissue Factor as a Key Determinant of IDH1 Mutant versus IDH1 Wild-type Glioma Thrombosis and Malignancy

项目摘要/摘要 浸润性胶质瘤是成人最常见的原发脑肿瘤，导致超过17,000人死亡。 美国每年都有。大约20%-30%的浸润性胶质瘤含有异柠檬酸突变 脱氢酶1(IDH1mut)。IDH1mut导致全球DNA高甲基化，这有助于胶质瘤的形成。 然而，IDH1突变的胶质瘤比没有这种突变的胶质瘤侵袭性要低得多。目前还不清楚 DNA超甲基化如何导致这种独特的表型。胶质瘤通常会在体内形成血栓。 肿瘤和整个血液循环。这些血栓很早就被认为是贫血症的预测指标。 结果。我们最近报道，IDH1突变的胶质瘤产生的血栓要少得多；我们的数据有力地表明 甲基化诱导的抑制F3，编码组织因子(TF)的基因，是原因。Tf是一种 强大的促凝剂，当癌症产生和释放时，会导致静脉血栓栓子(VTE)。这 约25%的胶质瘤患者会出现衰弱现象，但当IDH1mut存在时则不会。除了……之外 Tf结合并激活跨膜受体PAR2，从而触发血栓形成 由癌细胞表达，通过多种细胞内途径传递信号，促进肿瘤恶性进展。我们的 数据显示：(I)在所有直接参与凝血的基因中，F3mRNA的水平最强 (2)IDH1mut胶质瘤中F3甲基化水平显著高于IDH1wt胶质瘤； (Iii)IDH1mut胶质瘤的Tf蛋白水平始终低于IDH1wt胶质瘤；(Iv)IDH1mut胶质瘤的循环Tf低于IDH1wt胶质瘤 IDH1胶质瘤患者比IDH1wt胶质瘤患者少；(V)高循环Tf与VTE风险增加相关；(Vi) 含有内源性IDH1mut的患者来源的胶质瘤细胞产生的静脉血栓比IDH1wt更小、更少 异种移植小鼠模型中的胶质瘤；(Vii)抑制IDH1wt胶质瘤的转铁蛋白显著降低其体外和 体内恶性；()胶质瘤表达低转铁蛋白的患者的中位生存期是 胶质瘤患者表达高转铁蛋白，不依赖于IDH1mut。因此，我们假设甲基化- 诱导抑制转铁蛋白是较少血栓形成和较少恶性的IDH1突变的关键决定因素 表型。在目标1中，我们将最终确定F3超甲基化是IDH1突变的机制 取消显示TF表达式。在目标2中，我们将在一系列患者来源的IDH1wt中调节转铁蛋白的表达 和IDH1突变胶质瘤细胞，观察其对肿瘤诱导的血栓形成和恶性程度的影响。 在移植的小鼠身上。在目标3中，我们将使用分子和药理学方法来研究治疗 胶质瘤中阻断Tf-PAR2信号的可能性。此外，我们将前瞻性地评估 测定循环转铁蛋白水平，以及其他临床、血液和组织生物标记物，以创建 首个预测脑胶质瘤患者静脉血栓栓塞症风险的模型。总的来说，这项研究将极大地推动我们的 对IDH1突变肿瘤生物学的理解，并将提供有关新的治疗和诊断策略的信息 改善脑胶质瘤患者的护理。

PROJECT SUMMARY/ABSTRACT Infiltrative glioma is the most common type of primary brain tumor in adults, causing over 17,000 deaths in the United States every year. Approximately 20-30% of infiltrative gliomas contain mutations in isocitrate dehydrogenase 1 (IDH1mut). IDH1mut causes global DNA hypermethylation, which contributes to gliomagenesis. Yet, IDH1mut gliomas are significantly less aggressive than gliomas lacking this mutation. It has remained unclear how DNA hypermethylation leads to this unique phenotype. Gliomas often produce blood clots (thrombi) within the tumor and throughout the bloodstream. These thrombi have long been known to be predictors of poor outcome. We recently reported that IDH1mut gliomas produce far fewer thrombi; our data strongly indicate that methylation-induced suppression of F3, the gene encoding Tissue Factor (TF), is the reason why. TF is a powerful procoagulant that, when produced and released by cancers, causes venous thromboemboli (VTE). This debilitating phenomenon occurs in ~25% of glioma patients, but never when IDH1mut is present. In addition to triggering thrombosis, TF binds and activates protease-activated receptor 2 (PAR2), a transmembrane receptor expressed by cancer cells that signals through multiple intracellular pathways to promote tumor malignancy. Our data show that: (i) among all genes that directly participate in blood clotting, F3 mRNA levels have the strongest inverse relationship with IDH1mut; (ii) F3 methylation is significantly higher in IDH1mut gliomas than IDH1wt gliomas; (iii) TF protein levels are consistently lower in IDH1mut gliomas than IDH1wt gliomas; (iv) circulating TF is lower in patients with IDH1mut gliomas than IDH1wt gliomas; (v) high circulating TF correlates with increased VTE risk; (vi) patient-derived glioma cells with endogenous IDH1mut produce smaller and fewer venous thrombi than IDH1wt gliomas in xenograft mouse models; (vii) suppression of TF in IDH1wt gliomas greatly reduces their in vitro and in vivo malignancy; (viii) patients whose gliomas express low TF have more than double the median survival of patients whose gliomas express high TF, independent of IDH1mut. Thus, we hypothesize that methylation- induced suppression of TF is a critical determinant of the less thrombogenic, and less malignant, IDH1mut phenotype. In Aim 1, we will conclusively establish that F3 hypermethylation is the mechanism by which IDH1mut suppresses TF expression. In Aim 2, we will modulate the expression of TF in a series of patient-derived IDH1wt and IDH1mut glioma cells, observing the effects on tumor-induced thrombosis and malignancy in cell cultures and in engrafted mice. In Aim 3, we will use molecular and pharmacologic approaches to investigate the therapeutic potential of blocking TF-PAR2 signaling in gliomas. Further, we will prospectively evaluate the utility of determining circulating TF levels, along with other clinical, blood-based, and tissue-based biomarkers, to create the first predictive model of VTE risk in glioma patients. In total, this research will greatly advance our understanding of IDH1mut tumor biology, and it will inform regarding novel treatment and diagnostic strategies for improving glioma patient care.