|M.Sc Student||Ghanem Shorook|
|Subject||Heparanase Procoagulant Domain in Angiogenesis|
and Wound Healing
|Department||Department of Medicine||Supervisor||Dr. Yona Nadir|
|Full Thesis text|
Background: Heparanase, a β-D-endoglucuronidase abundant in platelets that was discovered thirty years ago, is an enzyme that cleaves heparan sulfate side chains on the cell surface and in the extracellular matrix yielding HS fragments of still appreciable size (5-7 kDa). Heparanase, known to be involved in angiogenesis and metastasis and to affect the hemostatic system in a non-enzymatic manner, was shown to form a complex with tissue factor (TF) and to enhance the generation of factor Xa. Our group demonstrated that peptides derived from TF pathway inhibitor (TFPI)-2 impeded the procoagulant effect of heparanase and attenuated inflammation, tumor growth and vascularization. Aims: The present study aimed to reveal potential role of the procoagulant domain of heparanase in angiogenesis and wound healing, in addition, to investigate whether the anticoagulant peptides can neutralize the effects of the heparanase procoagulant domain. Methods: Peptides 14 and 16 derived from the putative procoagulant domain that demonstrated by our group were studied in XTT proliferation assay to evaluate their effect on different tumor cell lines and endothelial cells. The release of heparanase from cells was studied by western blot analysis and immunostaining. Involvement of peptide 14 and 16 in wound healing process was investigated in a mouse model. Results: Peptides derived from the heparanase procoagulant domain induce increased proliferation and migration, release of heparanase and upregulation of heparanase, TF, TFPI and TFPI-2 in endothelial cells. These peptides also induced increased proliferation and release of heparanase from tumor cells. Thrombin had a similar effect on tumor cells proliferation and heparanase release. Effect of thrombin on proliferation was mediated through heparanase procoagulant domain. These results were reversed by peptides that inhibit the procoagulant domain. In the mouse model, heparanase procoagulant peptides enhanced wound healing. Conclusions: We found that the putative procoagulant domain of heparanase has an important role in cancer progression and wound healing. These finding supports the close direct relation between the hemostatic system and cancer progression.