Optimization of EphA2 antagonists based on a lithocholic acid core led to the identification of UniPR505, a new 3α-carbamoyloxy derivative with antiangiogenetic properties

The EphA2 receptor has been validated in animal models as new target for treating tumors depending on angiogenesis and vasculogenic mimicry. In the present work, we extended our current knowledge on structure-activity relationship (SAR) data of two related classes of antagonists of the EphA2 receptor, namely 5β-cholan-24-oic acids and 5β-cholan-24-oyl L-β-homotryptophan conjugates, with the aim to develop new antiangiogenic compounds able to efficiently prevent the formation of blood vessels. As a result of our exploration, we identified UniPR505, N-[3α-(Ethylcarbamoyl)oxy-5β-cholan-24-oyl]-L-β-homo-tryptophan (compound 14), as a submicromolar antagonist of the EphA2 receptor capable to block EphA2 phosphorylation and to inhibit neovascularization in a chorioallantoic membrane (CAM) assay.