A Novel Peptide Derived From Tissue‐Type Plasminogen Activator Potently Inhibits Angiogenesis and Corneal Neovascularization

Abstract

The recombinant protein TK1-2, which consists of two kringle domains of tissue-type plasminogen activator (t-PA), inhibits angiogenesis and tumor growth. ɪn this study, we examined the anti-angiogenic activities of peptides derived from kringle 2 domain of t-PA to identify the functional core sequence. Seven peptides were constructed from the kringle 2 sequence, based on the structure and characteristics of amino acid residues, and were analyzed for their inhibitory effects on endothelial cells (ECs). Among them, TP-7 (derived from a β-sheet motif) potently inhibited proliferation, tube formation, and migration of ECs in a dose-dependent manner, whereas truncation of 3-9 amino acid residues from either N or C terminus of TP-7 abrogated its inhibitory effects on ECs. TP-7 also potently inhibited angiogenesis in a Matrigel plug assay in vivo. Moreover, TP-7 dose-dependently suppressed corneal neovascularization induced by an acute chemical burn in a rat model. At the molecular level, TP-7 inhibited VEGF- or bFGF-induced phosphorylation of FAK and ERK1/2 and drastically disrupted VEGF- or bFGF-induced formation of stress fibers and focal adhesion complexes. In addition, TP-7 markedly suppressed attachment and spreading of ECs on a collagen type I or fibronectin matrix. Adhesion of ECs to immobilized TP-7 increased dose-dependently, which was disrupted strongly by pretreatment with soluble TP-7 and slightly by an integrin α2β1-blocking antibody. These results suggest that TP-7 is a potent anti-angiogenic peptide in part affecting the integrin α2β1-dependent pathway and that it can be used for treatment of corneal neovascularization by targeting VEGF and non-VEGF pathways. J. Cell. Biochem. 118: 1132-1143, 2017. © 2016 Wiley Periodicals, Inc.

Naringenin Eye Drops Inhibit Corneal Neovascularization by Anti-Inflammatory and Antioxidant Mechanisms

“…28,29 Therefore, great effort has been devoted to finding therapeutic alternatives for this condition. [30][31][32][33] Clinical studies have shown a beneficial effect of anti-VEGF treatment (Bevacizumab) for patients with corneal neovascularization. 34 Interestingly, polysaccharide extract from the naturally occurring Spirulina platensis was shown to be more cost effective in the treatment of corneal neovascularization induced by alkali in rats when compared with Bevacizumab.…”

Urokinase-derived peptide UP-7 suppresses tumor angiogenesis and metastasis through inhibition of FAK activation

“…In a modified Boyden chamber assay, treatment of HUVECs with UP-7 significantly inhibited bFGF- or VEGF-induced HUVEC migration dose-dependently (IC 50 = 16 µM and IC 50 = 15 µM, respectively), whereas Scr (100 µM) showed no inhibitory effect (Figure 1B ). Unexpectedly, UP-7 was not able to inhibit tube formation on Matrigel-coated plates differently from TP-7, the antiparallel β sheet-derived peptide of tissue type-plasminogen activator ( Supplementary Figure 2 ) [ 22 ].…”

“…It is notable that UP-7 which has the most potent anti-angiogenic activity is derived from the extended antiparallel β-sheet structure of UK1, because the most potent anti-angiogenic activity has been also shown in the antiparallel β-sheet structure-derived peptide (TP-7) among the peptides derived from the tissue type plasminogen activator kringle 2 domain [ 22 ]. The 33 mer peptide anginex that has been designed by using basic folding principles and incorporating short sequences from the β-sheet domains of anti-angiogenic proteins also demonstrates a potent anti-angiogenic activity [ 29 ].…”

Inhibition of Pathological Retinal Neovascularization by a Small Peptide Derived from Human Tissue-Type Plasminogen Kringle 2

“…TKII-12 was derived from the extended antiparallel b-sheet within the t-PA kringle 2 domain which also demonstrated antiangiogenic activity (Byeon et al, 1991;Carroll et al, 2005). Another peptide, TP-7, derived from t-PA kringle 2 inhibited VEGF or FGF-induced phosphorylation of ERK1/2 and FAK (Kim et al, 2017). Future studies are needed to identify the exact antiangiogenic mechanism of TKII-12.…”

“…In previous studies, Kim et al reported the recombinant protein TK1-2 and the t-PA kringle 2 domain alone inhibited angiogenesis in vitro and in vivo (Kim et al,2003;Carroll et al, 2005;Kang et al, 2006;Kim et al, 2008). Kim also reported a peptide derived from t-PA kringle 2 (named TP-7) that inhibited angiogenesis and corneal neovascularization (Kim et al, 2017). TP-7 was derived from an extended antiparallel b-sheet motif of t-PA kringle 2.…”