PhD Scientific Days 2026

Poster Session 1.I - Theoretical and Translational Medicine

Photoactivable tyrosine kinase inhibitors reduce VEGFR2 signaling in vitro in a structure-dependent manner

Name of the presenter

Antal, Réka

Institute/workplace of the presenter

Institute of Clinical Pathophysiology, Semmelweis University

Authors

Réka Antal¹, Balázs Besztercei¹, Attila Szappanos¹, Krisztián A. Kovács¹
1: Institute of Clinical Pathophysiology, Semmelweis University

Text of the abstract

Introduction: The hallmark of diseases with ocular neovascularization, such as wet age-related macular degeneration, is angiogenesis in the retina. This process is driven by excessive secretion of and signaling by vascular endothelial growth factor (VEGF), particularly through vascular endothelial growth factor receptor 2 (VEGFR2). A novel emerging approach to treat these conditions is the inhibition of growth factor receptors by small-molecule tyrosine kinase inhibitors (TKIs).
Aims: We studied three novel, structurally similar TKIs—EYE1090, EYE1091, and EYE1093—which are azidated, contain chlorine, fluorine, or bromine, respectively, and are otherwise identical. We hypothesized that a light-based approach could enable targeting of these molecules to specific tissues by permanently binding them to VEGFR2, thereby enhancing their inhibitory effect on angiogenesis. Our objective was to examine the effect of the TKIs on VEGFR2 signaling.
Methods: In this study, the TKIs were tested on VEGFR2 signal transduction using an ADP-Glo kinase assay, followed by Western blot. To determine the efficacy of the inhibitors in vitro, VEGFR2/NFAT reporter HEK293 cells were treated with the compounds, then with VEGF, and a luciferase reporter assay was performed. A flow cytometric analysis was carried out to assess the MDR1 efflux of the inhibitors from MDR1-HEK293 cells.
Results: Our findings indicate that all the compounds are strong inhibitors of VEGFR2 signaling in the absence of light, and their inhibitory effect increased substantially upon illumination in the assays performed. However, EYE1090 and EYE1093 were more potent, while EYE1091 was the least effective. These results align with the MDR1 efflux data, where EYE1091 exhibited the highest binding affinity to the transporter, which is assumed to decrease the intracellular concentration of the inhibitors.
Conclusion: Our new, chemically modified TKIs demonstrate strong inhibition of VEGFR2 signaling in vitro, although their potency is structure-dependent. Furthermore, it was confirmed that photoactivation enables targeted, permanent binding to VEGFR2; thus, the inhibitory potential of these molecules can be increased upon light exposure thanks to the azidation.
Funding: Supported by the European Commission via an EIC Pathfinder grant (101047120), and by the SE 250+ PhD Excellence Grant by Semmelweis University.