Vascular endothelial growth factor (VEGF)

Vascular endothelial growth factor (VEGF) is an important signalling molecule and an established target for anticancer therapies. As a result, the development and approval of RTKIs (receptor tyrosine kinase inhibitors) targeting VEGFR-2 have provided an important therapeutic strategy in the oncology field. However, an impaired cardiovascular function has been associated with these novel targeted therapies. Among the cardiovascular dysfunctions associated with these antiangiogenic drugs, hypertension represents the most common adverse effect. From the clinical evaluation of RTKI targeting VEGR-2, the incidence of hypertension appears to be associated with the potency of these therapeutics against VEGFR-2, such that agents with higher potency are associated with a higher incidence of hypertension ¹. During the first part of my PhD, I quantitatively measured the potency of these drugs, using the NFAT reporter gene assay. The binding between VEGFR-2 and its ligands initiates a signalling cascade, leading to activation of calcineurin and consequent dephosphorylation of the transcription factor NFAT. Next, NFAT translocates to the nucleus where it promotes the transcription of pro-angiogenic and pro-inflammatory genes ². By using HEK293T cells transfected with a luciferase gene, the NFAT reporter gene assay permits the quantification of the inhibitory effects of RTKIs on NFAT transcriptional activity ³. Indeed, RTKIs targeting VEGFR-2, by blocking VEGFR-2 signalling, determine a reduction of the NFAT-luciferase activity, thus producing a decrease of luminescence. The resulting pIC₅₀ values provided information about their potency, which will be essential for the subsequent in vivo characterisation of the cardiovascular consequences of these drugs.

References: 

1. León-Mateos, L., Mosquera, J. & Antón Aparicio, L. Treatment of sunitinib-induced hypertension in solid tumor by nitric oxide donors. Redox Biol 6, 421-425 (2015).
2. Simons, M., Gordon, E. & Claesson-Welsh, L. Mechanisms and regulation of endothelial VEGF receptor signalling. Nat Rev Mol Cell Biol 17, 611-625 (2016).
3. Hill, S.J., Baker, J.G. & Rees, S. Reporter-gene systems for the study of G-protein-coupled receptors. Curr Opin Pharmacol 1, 526-532 (2001).