OC-04 - Tissue factor positive microvesicles activate platelets in vitro and in vivo and enhance thrombosis in mice.

Autor: Hisada Y; Division of Hematology/Oncology, Thrombosis and Hemostasis Program, UNC McAllister Heart Institute., Geddings JE; Department of Pathology and Laboratory Medicine., Boulaftali Y; Department of Biochemistry and Biophysics., Getz TM; Department of Biochemistry and Biophysics., Whelihan M; Department of Medicine, University of North Carolina; Chapel Hill, North Carolina, USA., Fuentes R; Department of Pathology and Laboratory Medicine., Dee R; Department of Pathology and Laboratory Medicine., Cooley BC; Department of Pathology and Laboratory Medicine., Key NS; Division of Hematology/Oncology, Thrombosis and Hemostasis Program, UNC McAllister Heart Institute; Department of Pathology and Laboratory Medicine; Department of Medicine, University of North Carolina; Chapel Hill, North Carolina, USA., Wolberg AS; Department of Pathology and Laboratory Medicine., Bergmeier W; Department of Biochemistry and Biophysics., Mackman N; Division of Hematology/Oncology, Thrombosis and Hemostasis Program, UNC McAllister Heart Institute; Department of Pathology and Laboratory Medicine; Department of Biochemistry and Biophysics; Department of Medicine, University of North Carolina; Chapel Hill, North Carolina, USA.
Jazyk: angličtina
Zdroj: Thrombosis research [Thromb Res] 2016 Apr; Vol. 140 Suppl 1, pp. S169-70. Date of Electronic Publication: 2016 Apr 08.
DOI: 10.1016/S0049-3848(16)30121-9
Abstrakt: Introduction: Cancer patients have a 4- to 7- fold increased risk of venous thromboembolism (VTE) compared with general population. Most tumor cells express tissue factor (TF) and constitutively release small membrane microvesicles called tumor microvesicles (TMVs). Clinical studies have shown that circulating MP-TF activity is associated with VTE in pancreatic cancer but not in other types of cancer. Thrombin is a potent platelet agonist and activates platelets via protease activated receptors (PARs).
Aim: To determine the contribution of the TF+ TMV-thrombin-platelet pathway to cancer-associated thrombosis.
Materials and Methods: A human pancreatic adenocarcinoma cell line expressing high levels of TF (BxPc-3) was selected to study the effect of TF+ TMVs on platelet activation and thrombosis.
Results: TF+ TMVs induced platelet activation in vitro in a thrombin-dependent manner. The presence of orthotopically grown BxPc-3 tumors in mice was associated with increased levels of thrombin-antithrombin III complexes (TATc) and larger thrombi in an inferior vena cava stenosis model compared with control mice. Furthermore, injection of BxPc-3 TF+ TMVs into mice triggered platelet activation and enhanced venous thrombosis in a TF-dependent manner. Importantly, BxPc-3 TF+ TMV-enhanced thrombosis was reduced in Par4-deficient mice and wild-type mice treated with the platelet inhibitor clopidogrel, suggesting that platelet activation was required for the enhanced thrombosis.
Conclusions: These studies suggest that platelet inhibitors may reduce thrombosis in cancer patients with elevated levels of TF+ TMVs.
(© 2016 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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