Δ5-Cholenoyl-amino acids as selective and orally available antagonists of the Eph–ephrin system

Abstract

The Eph receptor-ephrin system is an emerging target for the development of novel anti-angiogenic therapies. Research programs aimed at developing small-molecule antagonists of the Eph receptors are still in their initial stage as available compounds suffer from pharmacological drawbacks, limiting their application in vitro and in vivo. In the present work, we report the design, synthesis and evaluation of structure-activity relationships of a class of Δ(5)-cholenoyl-amino acid conjugates as Eph-ephrin antagonists. As a major achievement of our exploration, we identified N-(3β-hydroxy-Δ(5)-cholen-24-oyl)-L-tryptophan (UniPR1331) as the first small molecule antagonist of the Eph-ephrin system effective as an anti-angiogenic agent in endothelial cells, bioavailable in mice by the oral route and devoid of biological activity on G protein-coupled and nuclear receptors targeted by bile acid derivatives.

UniPR1331, a small molecule targeting Eph/ephrin interaction, prolongs survival in glioblastoma and potentiates the effect of antiangiogenic therapy in mice

“…These drug discovery expeditions allowed to identify ATP-mimicking agents targeting Eph kinase domain or other pharmacological tools including peptides, proteins, antibodies and small molecules, targeting Eph/ephrin binding interface [ 12 ]. We actively contributed to this field discovering and optimizing several protein-protein interaction (PPI) inhibitors capable of preventing Eph-ephrin interaction [ 13 – 15 ] and including the first orally bioavailable Eph antagonist UniPR1331 [ 16 ]. UniPR1331 targets the ectodomain of EphA2 with a steady-state affinity constant (K D ) of 3.4 μM, dose-dependently blocked EphA2 phosphorylation in human umbilical vein endothelial cells (HUVEC) and reduced their ability to form blood vessels with an IC 50 of 2.9 μM [ 16 ].…”

“…We actively contributed to this field discovering and optimizing several protein-protein interaction (PPI) inhibitors capable of preventing Eph-ephrin interaction [ 13 – 15 ] and including the first orally bioavailable Eph antagonist UniPR1331 [ 16 ]. UniPR1331 targets the ectodomain of EphA2 with a steady-state affinity constant (K D ) of 3.4 μM, dose-dependently blocked EphA2 phosphorylation in human umbilical vein endothelial cells (HUVEC) and reduced their ability to form blood vessels with an IC 50 of 2.9 μM [ 16 ]. The compound inhibited the interaction of ephrin-A1 with all the EphA kinases and ephrin-B1 with all the EphB kinases [ 16 ] acting as a pan-Eph/ephrin inhibitor.…”

Therapeutic potential of targeting the Eph/ephrin signaling complex

“…In addition, UniPR139 shows improved bioavailability and can be detected in the plasma with a t 1/2 of 44 minutes. UniPR1331 was shown to be an anti-angiogenic agent in endothelial cells and orally bioavailable in a mouse model (Castelli et al, 2015). Moreover, UniPR1331 has been reported to possess anti-tumor activities in xenograft and orthotopic models of glioblastoma multiforme (Festuccia et al, 2018).…”

Advancement of Sialyltransferase Inhibitors: Therapeutic Challenges and Opportunities

“…Some examples of Lith derivatives exhibiting ST inhibition are commercially available, such as Lith (CAS: 434‐13‐9), lithocholylglycine (CAS: 474‐74‐8), and lithocholyltaurine (CAS: 516‐90‐5). However, the binding site for the Lith derivative is not clearly defined and could possibly be allosteric; these compounds are shown to exhibit a wide range of off‐target activities including inhibition of the nuclear pregnane X receptor, antagonism of the Eph‐ephrin system, activation of Vitamin D receptor, agonism of thee TGR5 receptor, interaction with acetylcholine receptors and increased invasiveness by upregulating urokinase‐type plasminogen activator receptor in colon cancer …”