Antiangiogenic Effect of (±)-Haloperidol Metabolite II Valproate Ester [(±)-MRJF22] in Human Microvascular Retinal Endothelial Cells

(±)-MRJF22 [(±)-2], a novel prodrug of haloperidol metabolite II (sigma-1 receptor antagonist/sigma-2 receptor agonist ligand) obtained by conjugation to valproic acid (histone deacetylase inhibitor) via an ester bond, exhibits antiangiogenic activity, being able to reduce human retinal endothelial cell (HREC) viability in a comparable manner to bevacizumab. Moreover, (±)-2 was able to significantly reduce viable cells count, endothelial cell migration, and tube formation in vascular endothelial growth factor A (VEGF-A) stimulated HREC cultures.