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This work is based on previous evidence showing that chemotactic sequence of the urokinase receptor (uPAR88-92) drives angiogenesis in vitro and in vivo in a protease-independent manner, and that the peptide Ac-Arg-Glu-Arg-Phe-NH2 (RERF) prevents both uPAR88–92- and VEGF-induced angiogenesis. New N-acetylated and C-amidated peptide analogues containing α-methyl α-amino acids were designed and synthesized to optimize the biochemical properties for therapeutic applications. Among these, Ac-L-Arg-Aib-L-Arg-D-Cα(Me)Phe-NH2, named UPARANT, adopts in solution a turned conformation similar to that found for RERF, is stable to sterilization in 3 mg/mL sealed vials in autoclave for 20 minutes at 120°C, is stable in blood, and displays a long-time resistance to enzymatic proteolysis. UPARANT competes with N-formyl-Met-Leu-Phe (fMLF) for binding to the formyl-peptide receptor, inhibits VEGF-directed endothelial cell migration, and prevents cytoskeletal organization and αvβ3 activation in endothelial cells exposed to VEGF. In vitro, UPARANT inhibits VEGF-dependent tube formation of endothelial cells at a 100× lower concentration than RERF. In vivo, UPARANT reduces to the basal level VEGF-dependent capillary sprouts originating from the host vessels that invaded Matrigel sponges implanted in mice, and completely prevents neovascularization induced by subcorneal implantation of pellets containing VEGF in rabbits. Both excellent stability and potency position UPARANT as a promising new therapeutic agent for the control of diseases fueled by excessive angiogenesis, such as cancer and inflammation. Mol Cancer Ther; 13(5); 1092–104. ©2014 AACR.

PDF file - 234K, Table S1 - Stability in physiological solution of UPARANT. Table S2 - Blood Stability of UPARANT. Table S3. Proton Chemical Shifts, 3JNH-alphaCH Coupling Constants of UPARANT at 298 K. Table S4. Average backbone torsion angles of RERF as obtained from RMD simulation in vacuo at 300 K. Figure S1 - 1H NMR spectra and selected regions of the ROESY spectra of UPARANT.

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PDR is characterized by neovascularization and a persistent grade of inflammation. N-formyl peptide receptors (FPRs) belong to a transmembrane G protein-coupled receptor superfamily able to modulate angiogenic and inflammatory responses. However, their involvement in PDR remains to be elucidated. Here, we examined FPR expression in human umbilical vein endothelial cells (HUVECs). We further assessed the capacity of vitreous fluid obtained from PDR patients after pars plana vitrectomy to induce pro-angiogenic/pro-inflammatory responses in endothelium and the contribution of FPR inhibitors to abrogate these responses.

Treatment of retinal neovascular diseases by anti-VEGF based therapies has two major flaws: one third of patients respond poorly, and chronic depletion of VEGF may have neurotoxic effects. We investigated in experimental rodent models of neovascular diseases the anti-angiogenic effects of a new synthetic molecule (UPARANT) designed to inhibit endothelial cells response to a wide variety of angiogenic triggers.

Bioconjugation is a rapidly expanding field because of the numerous potential applications of bioconjugate materials. We explored the usefulness of branched porphyrins as rigid scaffolds, bearing multiple sites for bioconjugation. To this end, we first selected the tetrakis(p-[aminomethyl] phenyl) porphyrin (TAMPP) macrocycle and developed a straightforward synthetic protocol, able to provide the desired tetraphenylporphyrin, carrying four functional amino groups. The partially protection of the amino groups by tert-butoxy-carbonyl allowed the selective and specific decoration of the porphyrin with different peptide sequences. To explore the utility of the macrocycle as molecular scaffold for bioconjugation, we selected peptide sequences able to function as thrombin inhibitors. In particular, two peptide sequences, named CS3 and ES7, able to interact, respectively, with the thrombin catalytic site and the fibrinogen recognition exosite, were joined onto the porphyrin macrocycle, providing the multisite-directed inhibitor CS3-TAMPP-ES7. This multisite inhibitor and its Mn(III) complex are able to inhibit α-thrombin-catalyzed hydrolysis of Tos-Gly-Pro-Arg-nitroanilide with inhibition constants in the micromolar range, as well as the hydrolysis of the natural substrate fibrinogen. The inhibitor is resistant against enzymatic degradation by thrombin and is highly selective. The Mn(III) complex is capable of interacting with clot-bound thrombin and partially inhibits clot growth in the presence of fibrinogen. The results herein reported are very promising, suggesting the potential of the newly developed conjugate as new imaging agents for clot detection.