Search

Purpose: Gliomas with isocitrate dehydrogenase 1 mutations (IDH1mut) are less aggressive than IDH1 wild-type (IDH1wt) gliomas and have global genomic hypermethylation. Yet it is unclear how specific hypermethylation events contribute to the IDH1mut phenotype. Previously, we showed that the gene encoding the procoagulant tissue factor (TF), F3, is among the most hypermethylated and downregulated genes in IDH1mut gliomas, correlating with greatly reduced thrombosis in patients with IDH1mut glioma. Because TF also increases the aggressiveness of many cancers, the current study explored the contribution of TF suppression to the reduced malignancy of IDH1mut gliomas. Experimental Design: TF expression was manipulated in patient-derived IDH1mut and IDH1wt glioma cells, followed by evaluation of in vitro and in vivo behavior and analyses of cell signaling pathways. Results: A demethylating agent, decitabine, increased F3 transcription and TF-dependent coagulative activity in IDH1mut cells, but not in IDH1wt cells. TF induction enhanced the proliferation, invasion, and colony formation of IDH1mut cells, and increased the intracranial engraftment of IDH1mut GBM164 from 0% to 100% (P = 0.0001). Conversely, TF knockdown doubled the median survival of mice engrafted with IDH1wt/EGFRvIIIamp GBM6, and caused complete regression of IDH1wt/EGFRamp GBM12 (P = 0.001). In vitro and in vivo effects were linked to activation of receptor tyrosine kinases (RTK) by TF through a Src-dependent intracellular pathway, even when extracellular RTK stimulation was blocked. TF stimulated invasion predominately through upregulation of β-catenin. Conclusions: These data show that TF suppression is a component of IDH1mut glioma behavior, and that it may therefore be an attractive target against IDH1wt gliomas.

BACKGROUND Venous thromboembolism (VTE) is a debilitating and life-threating condition that is common in patients with cancer, especially glioma. Antithrombotic prophylaxis is controversial in glioma patients because of possible intracerebral hemorrhage. Effective VTE prediction models exist for patients with other cancers, but not glioma. Our prior publications suggested a protective role of IDH1 mutations (IDHmut) against VTE, as well as a positive association between elevated circulating Tissue Factor (TF), a procoagulant secreted by cancers, and VTE in glioma patients. Others have recently found a correlation between podoplanin, a platelet activator, and tumor-associated VTE, but this has not been proven in gliomas. Our objective is to develop a multidimensional VTE prediction tool to improve glioma patient care, incorporating clinical, blood-based, histologic, and molecular markers. METHODS The Northwestern University Nervous System Tumor Bank provided preoperative arterial blood, tumor tissue, and clinical-pathologic data from 265 grade II-IV glioma patients over a 3-year interval. Molecular profiling was done by GlioSeq NGS. RESULTS Seventy-seven out of 265 grade II-IV glioma patients (29%) experienced VTE during their disease course. VTE was itself a negative prognostic marker for median overall survival (18 vs. 54 months, P< 0.001). Positive risk factors for VTE included advanced patient age, high body mass index, high tumor grade, prior history of VTE, coronary artery disease, hyperlipidemia, hypertension, and elevated circulating TF activity. While tumor expression of podoplanin positively correlated with VTE, circulating podoplanin did not. Among molecular markers, only IDHmut correlated with VTE risk, and it was associated with greatly reduced risk (OR=0.28; 95% CI=0.12–0.64, P=0.001). CONCLUSIONS This study identified multiple risk factors for glioma-associated VTE. Using these data, we are developing a multivariable prediction calculator that will improve patient care by identifying patients who would benefit most from prophylactic anticoagulation.