Cleaved High Molecular Weight Kininogen (HKa) and Kininostatin (D5) Induce Apoptosis and Inhibit Migration and Invasion of Human Prostate Cancer Cells by Preventing AKT Phosphorylation and Cyclin D1 Synthesis and Disrupting the Interaction of UPAR and EGFR.

Tumor metastasis is a major factor in the mortality rate in human prostate cancer. Upregulation and activation of EGFR and/or uPAR in a variety of cancers have been shown to be associated with poor prognosis. HK, a component of the plasma kallikrein-kinin system, can be hydrolyzed by plasma kallikrein to bradykinin and HKa. HKa and D5 both have been demonstrated to have potent anti-angiogenic activity in vitro and in vivo. We previously published that D5 directly inhibits human colon carcinoma cell (HCT-116) proliferation in vitro by blocking the G1/S transition in the cell cycle. We now show that HKa [100 nM] inhibits the migration of human prostate tumor cell (DU145) about 50%. Cyclin D1 can activate p21 and p27 with concomitant cell migration. DU145 cells rapidly increase cyclin D1 synthesis in response to bFGF [1.2 nM]. HKa suppresses cyclin D1 expression as shown by Western blotting as well as cell immunoflourescence. Stimulation by bFGF or VEGF results in clustering of uPAR and EGFR on the surface of DU145 cells. Immunoflourescence shows that the addition of HKa disrupts the co-localization of uPAR and EGFR. HKa or a monoclonal antibody against uPAR decreases the phosphorylation of EGFR at Tyr 1173. The phosphorylation of ERK and AKT, which are downstream effectors of EGFR, is also inhibited by HKa. Kininostatin [300nM] induced apoptosis of human prostate cancer cells challenged with uPA [50 nM] or EGF [6.7 nM]. Matrigel invasion assay reveals that HKa [100 nM] decreases the invading cell number by 90%. These novel data indicate that HKa and kininostatin induce apoptosis and inhibit migration and invasion of human prostate cancer cells, indicating the therapeutic potential of kininostatin in metastasis human prostate cancer.