Characterization of interactions and pharmacophore development for DFG-out inhibitors to RET tyrosine kinase

Area of Science:

• Biochemistry
• Molecular Biology
• Medicinal Chemistry

Background:

• Rearranged during transfection (RET) tyrosine kinase is a key target in human cancers.
• DFG-out multi-kinase inhibitors like Abt-348, Birb-796, Motesanib, and Sorafenib show RET inhibitory activity.
• Understanding structural requirements for DFG-out RET binding is crucial for type II inhibitor design.

Purpose of the Study:

• To elucidate the structural basis of RET inhibition by DFG-out multi-kinase inhibitors.
• To investigate the binding modes and interactions of specific RET inhibitors.
• To provide insights for the rational design of novel DFG-out RET inhibitors.

Main Methods:

• Homology modeling to determine the RET DFG-out conformation.
• Molecular docking and dynamics simulations to analyze inhibitor binding modes.
• Molecular mechanics/Poisson-Boltzmann surface area (MM/PBSA) for binding free energy calculations.
• Per-residue energy decomposition and e-pharmacophore modeling.

Main Results:

• Predicted binding affinities correlated well with experimental data, explaining activity differences.
• Detailed analysis of specific interactions between RET and inhibitors.
• Identification of common and distinct pharmacophore features across different RET-inhibitor complexes.

Conclusions:

• The study provides a structural understanding of DFG-out RET inhibition.
• The findings support the rational design of more effective RET-targeted cancer therapies.
• Computational methods successfully predicted and explained inhibitor efficacy.