Triazolopeptides Inhibiting the Interaction between Neuropilin-1 and Vascular Endothelial Growth Factor-165.

Bartlomiej Fedorczyk,Dagmara Tymecka,Piotr F J Lipiński,Gerard Y Perret,Beata Wilenska,Wioleta Dudka,Rafal Wieczorek,Aleksandra Misicka,Anna K Puszko

doi:10.3390/molecules24091756

Abstract

Inhibiting the interaction of neuropilin-1 (NRP-1) with vascular endothelial growth factor (VEGF) has become an interesting mechanism for potential anticancer therapies. In our previous works, we have obtained several submicromolar inhibitors of this interaction, including branched pentapeptides of general structure Lys(Har)-Xxx-Xxx-Arg. With the intent to improve the proteolytic stability of our inhibitors, we turned our attention to 1,4-disubstituted 1,2,3-triazoles as peptide bond isosteres. In the present contribution, we report the synthesis of 23 novel triazolopeptides along with their inhibitory activity. The compounds were synthesized using typical peptide chemistry methods, but with a conversion of amine into azide completely on solid support. The inhibitory activity of the synthesized derivatives spans from 9.2% to 58.1% at 10 μM concentration (the best compound Lys(Har)-GlyΨ[Trl]GlyΨ[Trl]Arg, 3, IC50 = 8.39 μM). Synthesized peptidotriazoles were tested for stability in human plasma and showed remarkable resistance toward proteolysis, with half-life times far exceeding 48 h. In vitro cell survival test resulted in no significant impact on bone marrow derived murine cells 32D viability. By means of molecular dynamics, we were able to propose a binding mode for compound 3 and discuss the observed structure–activity relationships.

Highlights

Neuropilin-1 (NRP-1), vascular endothelial growth factor receptor type-2 (VEGFR-2) and vascular endothelial growth factor 165 (VEGF165 ) form a complex (VEGFR-2/NRP-1/VEGF165 ), which modulates the process of angiogenesis [1]
Previous works have shown that strong inhibition of the NRP-1/VEGF165 interaction is obtained when the structure contains a C-terminal arginine (“anchor”) and a certain positively charged residue at the N-terminus (“arm”), spaced by two residues in the middle part (“linker”) [28,29,30,32]
We describe follow-up research whose intent was to see whether the introduction of 1,4-disubstituted 1,2,3-triazole rings as peptide bond isosteres could give derivatives with improved proteolytic stability that still retain the inhibitory activity

Summary

Introduction

Neuropilin-1 (NRP-1), vascular endothelial growth factor receptor type-2 (VEGFR-2) and vascular endothelial growth factor 165 (VEGF165 ) form a complex (VEGFR-2/NRP-1/VEGF165 ), which modulates the process of angiogenesis [1]. The interaction of VEGF165 with NRP-1 significantly increases. NRP-1 is expressed by endothelial cells of blood vessels, and by several immune system cell types such as plasmacytoid dendritic cells [4] or regulatory T cells (Tregs) [5]. It is believed that this phenomenon is caused by an autocrine pathway through the VEGF165 /NRP-1 axis, which favors cancer cells’ migration, proliferation, and growth [10], and increases their survivability [11]. Tregs tend to express large amounts of NRP-1 on their surface. Thanks to this, they migrate toward the source of the chemoattractant, tumor originated VEGF165 , and are recruited into the tumor microenvironment, causing cancer-associated immunosuppression [12]

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Results

Conclusion