-
[show abstract]
[hide abstract]
ABSTRACT: An increased incidence of thromboembolic events was observed during treatment with cisplatin-gemcitabine plus SU5416 (CG+SU5416), a tyrosine kinase inhibitor targeting the vascular endothelial growth factor (VEGF) receptor-1 and -2. Nine thromboembolic events occurred in eight of 19 patients. We performed an analysis of parameters of the coagulation cascade and vessel wall activation.
Markers for thrombin generation and endothelial cell activation were measured in three patients treated with CG+SU5416, two of whom developed a thromboembolic event. The results were compared with measurements in six patients treated with CG alone, and in 17 patients treated with SU5416 alone.
During cycles 1 and 2 of treatment with CG+SU5416, a significant cycle-dependent activation of both the coagulation cascade and endothelial cells occurred, whereas platelet counts decreased. Change in platelet number had a significant negative predictive effect on soluble (s)-E-selectin levels. Significant activation of the coagulation cascade only was observed in the patients treated with CG alone, whereas in patients treated with SU5416 alone, significant endothelial cell activation was observed.
We hypothesize that endothelial cells deprived of VEGF after exposure to SU5416 became activated and more susceptible to damage during treatment with CG+SU5416, which was aggravated by a transient decrease in platelets, which are, among other things, carriers of VEGF. These results suggests that VEGF, in addition to being a permeability, proliferation, and migration factor, also is a maintenance and protection factor for endothelial cells, and that platelets may have a role in maintaining vascular integrity.
Journal of Clinical Oncology 07/2003; 21(11):2192-8. · 18.37 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The angiogenesis inhibitor SU5416 is a potent inhibitor of vascular endothelial growth factor (VEGF) receptor-1 and -2. VEGF may be involved in hemostasis by altering the hemostatic properties of endothelial cells. We analyzed the effects of SU5416 on the coagulation cascade and the vessel wall in patients with advanced cancer.
Markers for thrombin generation, activation of the protein C pathway, fibrinolysis, and endothelial cell activation were measured in patients with renal cell carcinoma, soft tissue sarcoma, or melanoma on days 0, 14, and 28 of treatment with SU5416. Three of 17 sampled patients developed a thromboembolic event in the fifth week of treatment. Markers for thrombin generation and fibrinolysis did not show significant changes. We observed a significant increase in endogenous thrombin potential and of parameters reflecting endothelial cell activation (von Willebrand antigen, soluble tissue factor, and soluble E-selectin) in all patients (P< or =0.001). In patients experiencing a thromboembolic event, endogenous thrombin potential, soluble tissue factor, and soluble E-selectin increased to a significantly greater extent (P=0.029, P=0.021, and P=0.007, respectively).
VEGF is not only a permeability, proliferation, and migration factor, but it is also a maintenance and protection factor for endothelial cells.
Arteriosclerosis Thrombosis and Vascular Biology 09/2002; 22(9):1500-5. · 6.37 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Angiogenesis and activated blood coagulation are involved in tumor growth and metastasis. Although some have suggested that activation of coagulation in tumors is not linked to activation of platelets, no data exist to either support or refute this concept. However, platelet turnover in cancer patients is often increased, and platelets are carriers of angiogenic growth factors. We hypothesized that platelets are involved in tumor-associated angiogenesis. To obtain evidence supporting this hypothesis, we have studied whether the angiogenic and coagulation pathways and platelets are concomitantly activated in cancer patients with soft tissue sarcomas (STSs) using a novel method to detect activated platelets in tumor specimens. Twelve patients with STS were selected on the basis of having intratumoral accumulation of fluid, which was aspirated. These accumulations demonstrated very high concentrations of vascular endothelial growth factor and coagulation factors (including thrombin-antithrombin-complex). Tumor specimens showed dense vascularization with intense vascular endothelial growth factor expression and the presence of activated platelets. Taken together, these results support the concept that angiogenesis, blood coagulation, and platelets are concomitantly activated in STS and support the hypothesis that platelets contribute to tumor-induced angiogenesis.
Clinical Cancer Research 02/2000; 6(1):166-71. · 7.74 Impact Factor
