Methylation-dependent Tissue Factor Suppression Contributes to the Reduced Malignancy of IDH1-mutant Gliomas

Abstract

Purpose: Gliomas with isocitrate dehydrogenase 1 mutations (IDH1 mut) are less aggressive than IDH1 wild-type (IDH1 wt) gliomas and have global genomic hypermethylation. Yet it is unclear how specific hypermethylation events contribute to the IDH1 mut phenotype. Previously, we showed that the gene encoding the procoagulant tissue factor (TF), F3, is among the most hypermethylated and downregulated genes in IDH1 mut gliomas, correlating with greatly reduced thrombosis in patients with IDH1 mut glioma. Because TF also increases the aggressiveness of many cancers, the current study explored the contribution of TF suppression to the reduced malignancy of IDH1 mut gliomas. Experimental Design: TF expression was manipulated in patient-derived IDH1 mut and IDH1 wt 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 IDH1 mut cells, but not in IDH1 wt cells. TF induction enhanced the proliferation, invasion, and colony formation of IDH1 mut cells, and increased the intracranial engraftment of IDH1 mut GBM164 from 0% to 100% (P ¼ 0.0001). Conversely, TF knockdown doubled the median survival of mice engrafted with IDH1 wt /EGFRvIII amp GBM6, and caused complete regression of IDH1 wt /EGFR amp GBM12 (P ¼ 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 b-catenin. Conclusions: These data show that TF suppression is a component of IDH1 mut glioma behavior, and that it may therefore be an attractive target against IDH1 wt gliomas.

Primary and recurrent glioma patient-derived orthotopic xenografts (PDOX) represent relevant patient avatars for precision medicine

“…Importantly, our models retain R132H IDH1 heterozygosity and efficient production of 2HG 79 . In vitro cultures derived from these tumors either died or led to depletion of the wildtype IDH1 allele, in line with previous reports 49,80 , suggesting that IDH1mut gliomas require components of the brain microenvironment to maintain their growth. Importantly, our fully annotated cohort displays a wide variety of genetic features not recapitulated in other models (e.g., EGFR and PDGFRA amplification), thus reflecting the wide inter-patient heterogeneity of high-grade gliomas.…”

Beyond thrombosis: the impact of tissue factor signaling in cancer

“…In contrast, we found that gliomas with mutations in isocitrate dehydrogenase 1 or IDH2 (collectively "IDH mut ") hypermethylate the early coding region of F3 and suppress its transcription, correlating with less flTF-MV production, less risk of VTE, and less aggressive behavior [116,117]. This appears to be unique to IDH mut gliomas, as other IDH mut cancers, like cholangiocarcinoma and acute myeloid leukemia, neither hypermethylate F3 nor suppress TF production [51,116].…”

“…However, the response of cancers to TF likely depends on their molecular background. For example, we found that GBM cells with driver mutations in EGFR are far more dependent on endogenous TF for cell proliferation than GBM cells with driver mutations in NF1 [116].…”

“…flTFmediated activation of PAR2 also recruits actin-binding protein to the cytoplasmic domain of flTF, and promotes cytoskeleton reorganization and cell motility by activating MAPK and cofilin pathways [62,63,168]. Activated PAR2 stabilizes and increases β-catenin expression [169], and in glioma, the pro-invasive effects of flTF: FVIIa is dependent in part on β-catenin [116]. However, flTF-β1 integrin interaction promotes cell migration when the flTF cytoplasmic domain is phosphorylated [55], suggesting the requirement of PAR2 activation.…”

Impact of Tumor Genomic Mutations on Thrombotic Risk in Cancer Patients

“…Mutations in KRAS have been associated with increased tumor tissue factor expression in CRC and lung cancer [ 72 , 73 ]. Mutations in IDH1 led to hypermethylation of the F3 promoter of the tissue factor gene leading to decreased expression and may explain the decreased risk of VTE in primary brain cancer patients with mutant IDH1 [ 42 , 74 ]. Inflammation is known to induce a prothrombotic state and might play a role in cancer associated VTE [ 75 , 76 ].…”