Comparative in silico Survey of Retinoic Acids as Putative Biomolecules Against VEGF Receptors: A Glycomics-based Approach

In this study, putative interactions between all of the retinoic acid (RA) ligands (all-trans (At), 9-cis (9c), and 13-cis (13c)), and VEGF receptors (VEGFR-1, -2 and -3) were investigated. It was performed considering the glycosylation status of the receptors to achieve a more reliable mode of interactions based on glycomics. We found that RAs may have a higher affinity for ligand-binding domains in VEGFRs. Furthermore, all RA isomers can strongly attach to VEGFR-3 receptor in comparison to other ones. It was also demonstrated that receptor dimerization of RAs may be less targeted. Moreover, regarding post-translational modifications, glycosylated structures showed conflicting binding energies. RAs may target the human vasculature, specifically lymph vessels, through VEGFR-3. In addition, the ligand binding-mediated activation of VEGFRs may be affected by these agents. Also, the glycosylation status of the receptors can interfere with these manners. Furthermore, our results confirmed that the consideration of carbohydrates in crystal structures is essential for a better interpretation of ligand/receptor interactions during drug discovery studies. Even though these observations improved our understanding of the binding patterns of RAs to VEGFRs, validation of these results needs further analysis to introduce these biomolecules as anti-VEGF remedies.