Thrombin Up-regulates Cathepsin D which Enhances Angiogenesis, Growth, and Metastasis

L. Hu, J. M. Roth, P. Brooks, J. Luty, S. Karpatkin
2008 Cancer Research  
Cathepsin D (CD) up-regulation has been associated with human malignancy and poor prognosis. Thrombin upregulated CD mRNA and protein in eight tumor cell lines as well as in human umbilical vascular endothelial cells (HUVEC). Thrombin increased the secretion of CD by 3-to 8-fold and enhanced chemotaxis (f2-fold) in 4T1 murine mammary CA cells, which was completely inhibited with the knockdown of CD. Secreted 4T1 CD induced neoangiogenesis by 2.4-fold on a chick chorioallantoic membrane, which
more » ... c membrane, which was blocked in CD-KD cells. The addition of pure CD (2 ng) to the chick chorioallantoic membrane increased angiogenesis by 2.1-fold, which was completely inhibited by Pepstatin A (Pep A). CD enhanced human HUVEC chemotaxis and Matrigel tube formation by 2-fold, which was then blocked by Pep A. CD enhanced HUVEC matrix metalloproteinase 9 (MMP-9) activity by f2-fold, which was completely inhibited by Pep A as well as a generic MMP inhibitor, GM6001. The injection of CD-KD 4T1 cells into syngeneic mice inhibited tumor growth by 3-to 4-fold compared with empty vector (EV) cells. Hirudin, a specific thrombin inhibitor, inhibited the growth of wild-type and EV cells by 2-to 3-fold, compatible with thrombin up-regulation of CD. CD and thrombin also contributed to spontaneous pulmonary metastasis; 4-fold nodule inhibition with CD versus EV and 4.6-fold inhibition with hirudin versus EV (P < 0.02). Thus, thrombin-induced CD contributes to the malignant phenotype by inducing tumor cell migration, nodule growth, metastasis, and angiogenesis. CD-induced angiogenesis requires the proteolytic activation of MMP-9. [Cancer Res 2008;68(12):4666-73] Requests for reprints: Simon Karpatkin, New
doi:10.1158/0008-5472.can-07-6276 pmid:18559512 fatcat:wxjjmzf5rrco3eknjmixqxgdsy