Clinical Trainee: Erica Gruber, Resident in Clinical Pathology
Collaborator: James Catalfamo
Contact Information: Email: firstname.lastname@example.org; Phone: 607/253-3255
Sponsor: Clinical Research Grants Program
Grant Number: N/A
Title: Procoagulant Properties of Canine Hemangiosarcoma
Annual Direct Cost: $8,000
Project Period: 02/01/11-01/31/12
DESCRIPTION (provided by applicant): Dogs with hemangiosarcoma frequently suffer from disseminated intravascular coagulation (DIC), a hemostatic disorder that contributes to patient morbidity and mortality. DIC results from systemic uncontrolled activation of the coagulation cascade. The underlying mechanism by which DIC is initiated in dogs with this neoplasm is unknown. In this study, we hypothesize that hemangiosarcoma cells aberrantly express tissue factor (TF) and release procoagulant membrane-derived microparticles into circulation. These procoagulant factors may contribute to the development of DIC in dogs with hemangiosarcoma. TF is the main activator of the coagulation cascade. Microparticles accelerate and disseminate the coagulative process by virtue of their small size and expression of the anionic phospholipid, phosphatidylserine, which is the surface scaffold on which coagulation proceeds. We will test this hypothesis by using immunological- and functional-based assays to measure TF and microparticle release in different hemangiosarcoma cell lines compared to non-neoplastic canine endothelial cells (EC). In Aim 1, we will assess TF mRNA expression with semi-quantitative RT-PCR and TF protein expression with immunofluorescent microscopy and flow cytometric assays. We will also measure TF activity on cell surfaces with a procoagulant assay. In Aim 2, we will semi-quantify microparticle release using flow cytometry and evaluate the procoagulant properties of the microparticles through measurement of TF activity and thrombin generation assays.
We expect to find that canine hemangiosarcoma cells express high concentrations of functionally active TF and shed procoagulant microparticles into the culture supernatant whereas non-neoplastic ECs will not express TF or release microparticles. Since these procoagulant factors can influence tumor cell behavior by directly stimulating cancer growth, survival, invasion, and metastasis, their existence in canine hemangiosarcoma has implications beyond that of hemostatic dysfunction. TF, in particular, could prove to be a novel target for decreasing metastasis and directing delivery of chemotherapeutic agents to the neoplasm. This project can be readily completed in the 1-year funding period because all the proposed assays are well established in Dr. Stokol’s laboratory or in the laboratory of our collaborator, Dr. Catalfamo.
Dr. Gruber, a resident in Clinical Pathology, will perform all assays under the direct supervision of Dr. Stokol, with the assistance of Dr. Catalfamo for the thrombin generation assays. Dr. Gruber will also be the primary person responsible for data analysis and manuscript preparation, under the guidance of Dr. Stokol. Dr. Catalfamo has read this proposal, provided input on study design and will assist with data interpretation of the thrombin generation assays and manuscript preparation.