Integrating computational and chemical biology tools in the discovery of antiangiogenic small molecule ligands of FGF2 derived from endogenous inhibitors.

Chiara Foglieni,Giorgio Colombo,Domenico Ribatti,Marco Rusnati,Elisabetta Moroni,Andrea Resovi,Laura Ragona,Antonella Bugatti,Katiuscia Pagano,Denise Pinessi,Marco Lessi,Giulia Taraboletti,Fabio Bellina,Sabrina Bertini

doi:10.1038/srep23432

Abstract

The FGFs/FGFRs system is a recognized actionable target for therapeutic approaches aimed at inhibiting tumor growth, angiogenesis, metastasis, and resistance to therapy. We previously identified a non-peptidic compound (SM27) that retains the structural and functional properties of the FGF2-binding sequence of thrombospondin-1 (TSP-1), a major endogenous inhibitor of angiogenesis. Here we identified new small molecule inhibitors of FGF2 based on the initial lead. A similarity-based screening of small molecule libraries, followed by docking calculations and experimental studies, allowed selecting 7 bi-naphthalenic compounds that bound FGF2 inhibiting its binding to both heparan sulfate proteoglycans and FGFR-1. The compounds inhibit FGF2 activity in in vitro and ex vivo models of angiogenesis, with improved potency over SM27. Comparative analysis of the selected hits, complemented by NMR and biochemical analysis of 4 newly synthesized functionalized phenylamino-substituted naphthalenes, allowed identifying the minimal stereochemical requirements to improve the design of naphthalene sulfonates as FGF2 inhibitors.

Highlights

The activity of FGFs requires signaling triggered by a ternary complex formed by FGFs, cell surface heparan sulfate proteoglycans (HSPGs) and FGFRs2
We demonstrated that direct binding and sequestration of FGF2, through a sequence located in the type III repeats, is a mechanism of the antiangiogenic activity of TSP-114, indicating that TSP-1 could represent a model for the development of new extracellular FGF2 inhibitors
The great potential of FGF2 inhibitors as antineoplastic therapeutics lies in the fact that a number of tumor types are intrinsically dependent on the FGF/FGFR signaling, that induces angiogenesis, exerts pleiotropic effects on both the tumor cells and the surrounding stroma and mediates resistance to antiangiogenc and targeted therapies[1,2,6,8]

Summary

Introduction

The activity of FGFs requires signaling triggered by a ternary complex formed by FGFs, cell surface heparan sulfate proteoglycans (HSPGs) and FGFRs2. We set out to expand the number of new small molecules targeting FGF2, by investigating the chemical space around SM27 and evaluating the activity of the resulting compounds with the perspective of evolving them into potential drug candidates. To this end, we first used molecular similarity criteria and docking calculations to screen the NCI database in search for molecules sharing with SM27 the structural and physico-chemical determinants necessary for binding to FGF2. Our results show that the use of structural characterization of a starting complex, combined with chemo-informatics approaches can aptly be exploited for the discovery of new leads for further development into effective and more drug-like anticancer compounds

Methods

Results

Conclusion