Targeting a metalloprotease-PAR1 signaling system with cell-penetrating pepducins inhibits angiogenesis, ascites, and progression of ovarian cancer.

Gene chip and proteomic analyses of tumors and stromal tissue has led to the identification of dozens of candidate tumor and host components potentially involved in tumor-stromal interactions, angiogenesis, and progression of invasive disease. In particular, matrix metalloproteases (MMP) have emerged as important biomarkers and prognostic factors for invasive and metastatic cancers. From an initial screen of benign versus malignant patient fluids, we delineated a metalloprotease cascade comprising MMP-14, MMP-9, and MMP-1 that culminates in activation of PAR1, a G protein-coupled protease-activated receptor up-regulated in diverse cancers. In xenograft models of advanced peritoneal ovarian cancer, PAR1-dependent angiogenesis, ascites formation, and metastasis were effectively inhibited by i.p. administration of cell-penetrating pepducins based on the intracellular loops of PAR1. These data provide an in vivo proof-of-concept that targeting the metalloprotease-PAR1 signaling system may be a novel therapeutic approach in the treatment of ovarian cancer.