hirudin and Pancreatic-Neoplasms

The risk of thrombotic complications such as deep vein thrombosis (DVT) during tumor development is well known. Tumors release into the circulation procoagulant microparticles (MPs) that can participate in thrombus formation following vessel injury. The importance of this MP tissue factor (TF) in the initiation of cancer-associated DVT remains uncertain.. To investigate how pancreatic cancer MPs promote DVT in vivo.. We combined a DVT mouse model in which thrombosis is induced by flow restriction in the inferior vena cava with one of subcutaneous pancreatic cancer in C57BL/6J mice. We infused high-TF and low-TF tumor MPs to determine the importance of TF in experimental cancer-associated DVT.. Both tumor-bearing mice and mice infused with tumor MPs subjected to 3 h of partial flow restriction developed an occlusive thrombus; fewer than one-third of the control mice did. We observed that MPs adhered to neutrophil extracellular traps (NETs), which are functionally important players during DVT, whereas neither P-selectin nor glycoprotein Ib were required for MP recruitment in DVT. The thrombotic phenotype induced by MP infusion was suppressed by hirudin, suggesting the importance of thrombin generation. TF carried by tumor MPs was essential to promote DVT, as mice infused with low-TF tumor MPs had less thrombosis than mice infused with high-TF tumor MPs.. TF expressed on tumor MPs contributes to the increased incidence of cancer-associated venous thrombosis in mice in vivo. These MPs may adhere to NETs formed at the site of thrombosis.

Topics: Animals; Antithrombins; Carcinoma, Pancreatic Ductal; Cell Line, Tumor; Cell-Derived Microparticles; Disease Models, Animal; Extracellular Traps; Hirudins; Ligation; Male; Mice, Inbred C57BL; Mice, Knockout; P-Selectin; Pancreatic Neoplasms; Platelet Glycoprotein GPIb-IX Complex; Regional Blood Flow; Thromboplastin; Vena Cava, Inferior; Venous Thrombosis

Using a chemoinvasion assay, we show that platelets promote invasiveness of 5 pancreatic adenocarcinoma cell lines.. Gelatin zymography and Western blot analysis were performed to detect metalloproteinase-9 (MMP-9) secreted from tumor cells in the presence or absence of platelets. The effects of antiplatelet agents on the invasiveness of tumor cells and the secretion level of MMP-9 were evaluated.. The number of traversed tumor cells significantly increased when incubated with platelets compared without platelets in all cell lines. The MMP-9 band was detected in all tumor cell lines, and the intensity was obviously greater in conditions of incubation with platelets than without. In the experiment of antiplatelet agents effects, it was confirmed that invasiveness of tumor cells significantly decreased following incubation with cilostazol depending on the concentration in spite of the presence of platelets. The level of MMP-9 also significantly decreased in the ELISA analysis.. These data mean platelets activate invasiveness of tumor cells because of enhanced MMP-9 secretion. Furthermore, anti-platelet drugs may inhibit invasiveness of tumor cells due to decreased MMP-9 secretion, and this inhibition may lead to the suppression of tumor cell invasion. We propose that antiplatelet agents are applicable in clinical treatment to inhibit metastasis of malignant tumor cells.

Topics: Adenocarcinoma; Adenosine Diphosphate; Adult; Blood Platelets; Cell Line, Tumor; Cilostazol; Collagen; Drug Combinations; Drug Screening Assays, Antitumor; Eicosapentaenoic Acid; Epoprostenol; Hirudins; Humans; Laminin; Matrix Metalloproteinase 9; Neoplasm Invasiveness; Neoplasm Proteins; Pancreatic Neoplasms; Platelet Activation; Platelet Aggregation Inhibitors; Proteoglycans; Tetrazoles; Thrombin

Tumor cell-induced platelet aggregation (TCIPA) is considered to be a critical step in hematogenous metastasis.. TCIPA was studied in vitro in six human pancreatic carcinoma cell lines (PC 3, PC 44, AsPC1, BxPC3, Capan2, Panc1).. Whereas all cell lines induced aggregation of washed platelets in the presence of minimal amounts of platelet-poor plasma, five cell lines also induced aggregation of platelets in platelet-rich plasma. The thrombin-antagonist hirudin inhibited TCIPA in all cell lines indicating that TCIPA is thrombin-dependent. Since pretreatment of tumor cells with phospholipase A2 or C inhibited TCIPA, the thrombin-generating activity might be confined to the tumor cell surface. Further support for a prothrombinase activity was provided by the observation that all cell lines were able to induce the aggregation of washed platelets after addition of purified coagulation factors II and V.. Pancreatic carcinoma cells are able to induce platelet aggregation via activation of thrombin. This might support metastasis in pancreatic cancer and possibly explain the incidence of thrombosis in this tumor.

Topics: Antithrombins; Hirudins; Humans; Neoplasm Metastasis; Pancreatic Neoplasms; Platelet Aggregation; Platelet Aggregation Inhibitors; Thrombin; Tumor Cells, Cultured