Targeting homologous recombination (HR) repair mechanism for cancer treatment: discovery of new potential UCHL-3 inhibitorsviavirtual screening, molecular dynamics and binding mode analysis

UCHL3 (ubiquitin C-terminal hydrolase-L3) is a de-ubiquitinating enzyme involved in the homologous recombination repair mechanism of double-strand breaks (DBS) of the DNA. Multiple studies indicated that UCHL3 inhibitors could be used in combination therapy with high therapeutic efficacy against cancer thus highlighting the validity of directing research against UCHL3 as a druggable target in oncology. In this study, a combination of virtual screening methods was utilized to identify new potential UCHL3 inhibitors. A series of UCHL3 ligands were identified by applying a combination of cheminformatics and molecular modeling filtration techniques to a ChemBl database of over two million small moleculesviz.Lipinski's Rule of Five, Veber's rule, pharmacophore model, Hierarchical molecular docking, Pan-assay Interference Compounds (PAINS) alerts, toxicity filter, and single-point Molecular mechanics Poisson/Boltzmann surface area (MM/PBSA) docking pose rescoring. This multi-layer filtration strategy led to the identification of twenty-one compounds as potential UCHL3 inhibitors that were subsequently subjected to a 50 ns molecular dynamics (MD) simulations predict the stability of their ligand-protein complexes. Furthermore, MM/PBSA calculations based on MD trajectories were performed, and the energy contribution per residue to the binding energy was calculated. Three compounds,1,2and3, were finally recognized as having the highest potential of being UCHL3 inhibitors. Therefore, those were used for binding mode analysis to the UCHL3 active site, leading to identification of four residues as key for bindingviz.Pro8, Leu55, Val166, and Leu168. Communicated by Ramaswamy H. Sarma

Automated summary

Virtual screening methods were utilized to identify potential UCHL3 inhibitors, resulting in the identification of 21 compounds. Molecular dynamics simulations were used to predict the stability of these compounds, ultimately identifying three as having the highest potential. Binding mode analysis revealed four key residues for binding at the UCHL3 active site.