Cleaved high molecular weight kininogen and its domain 5 inhibit migration and invasion of human prostate cancer cells via the epidermal growth factor receptor pathway

Up-regulation and activation of epidermal growth factor receptor and/or urokinase-type plasminogen activator receptor in a variety of cancers have been shown to be associated with poor prognosis. High molecular weight kininogen can be hydrolyzed by plasma kallikrein to bradykinin and HKa. HKa and its domain 5 (D5) both have been demonstrated to have potent anti-angiogenic activity. We now show that HKa blocks human prostate cancer cell (DU145) migration by 76.0±2.4% at 300nM and invasion by 78.0±12.9% at 11.1nM. D5 inhibits tumor migration and invasion in a concentration-dependent manner. Stimulation by bFGF or VEGF results in clustering of uPAR and EGFR on the surface of DU145 cells. The co-localization of uPAR and EGFR is prevented by HKa. Immunoprecipitation suggests that uPAR, EGFR and α5β1 integrin formed a ternary complex. Immunoblotting demonstrates that HKa significantly decreases the bFGF-transactivated phosphorylation of EGFR at Tyr 1173 between 30min and 4hr. The phosphorylation of ERK and AKT, which are downstream effectors of EGFR, is also inhibited by HKa. These novel data indicate that HKa and D5 inhibit migration and invasion of human prostate cancer cells via a EGFR/uPAR pathway, suggesting the therapeutic potential of HKa and D5 to decrease metastasis of human prostate cancer.