Ixolaris, a tissue factor inhibitor, blocks primary tumor growth and angiogenesis in a glioblastoma model

T. C. Carneiro-Lobo, S. Konig, D. E. Machado, L. E. Nasciutti, M. F. Forni, I. M.B. Francischetti, M. C. Sogayar, R. Q. Monteiro

Research output: Contribution to journalArticle

59 Citations (Scopus)


Background: The expression levels of the clotting initiator protein Tissue Factor (TF) correlate with vessel density and the histological malignancy grade of glioma patients. Increased procoagulant tonus in high grade tumors (glioblastomas) also indicates a potential role for TF in progression of this disease, and suggests that anticoagulants could be used as adjuvants for its treatment. Objectives: We hypothesized that blocking of TF activity with the tick anticoagulant Ixolaris might interfere with glioblastoma progression. Methods and results: TF was identified in U87-MG cells by flow-cytometric and functional assays (extrinsic tenase). In addition, flow-cytometric analysis demonstrated the exposure of phosphatidylserine in the surface of U87-MG cells, which supported the assembly of intrinsic tenase (FIXa/FVIIIa/FX) and prothrombinase (FVa/FXa/prothrombin) complexes, accounting for the production of FXa and thrombin, respectively. Ixolaris effectively blocked the in vitro TF-dependent procoagulant activity of the U87-MG human glioblastoma cell line and attenuated multimolecular coagulation complexes assembly. Notably, Ixolaris inhibited the in vivo tumorigenic potential of U87-MG cells in nude mice, without observable bleeding. This inhibitory effect of Ixolaris on tumor growth was associated with downregulation of VEGF and reduced tumor vascularization. Conclusion: Our results suggest that Ixolaris might be a promising agent for anti-tumor therapy in humans.

Original languageEnglish
Pages (from-to)1855-1864
Number of pages10
JournalJournal of Thrombosis and Haemostasis
Issue number11
Publication statusPublished - Nov 2009



  • Angiogenesis
  • Anticoagulant therapy
  • Glioblastoma
  • Ixolaris
  • Primary tumor growth
  • Tissue factor

ASJC Scopus subject areas

  • Hematology

Cite this

Carneiro-Lobo, T. C., Konig, S., Machado, D. E., Nasciutti, L. E., Forni, M. F., Francischetti, I. M. B., Sogayar, M. C., & Monteiro, R. Q. (2009). Ixolaris, a tissue factor inhibitor, blocks primary tumor growth and angiogenesis in a glioblastoma model. Journal of Thrombosis and Haemostasis, 7(11), 1855-1864. https://doi.org/10.1111/j.1538-7836.2009.03553.x