Development of Dynamic Structure‐Based Pharmacophore Models to Target OX40–OX40L Interaction With Potential Small Molecule Therapeutics: Targeting Tumor Microenvironment

ABSTRACT OX40, primarily expressed on activated T cells, engages with its ligand, OX40L, expressed on antigen‐presenting cells, creating a co‐stimulatory signal that amplifies T cell activation. This interaction enhances T‐cell survival, proliferation, and the production of effector cytokines. The OX40–OX40L axis plays a crucial role in modulating immune responses, maintaining a delicate equilibrium between robust immune reactions and preventing excessive inflammation. Dysregulation of this interaction has been associated with autoimmune diseases and cancer. In the current study, we developed a virtual screening pipeline to screen small molecule libraries targeting the OX40–OX40L interaction. We developed dynamic target‐based pharmacophore models and employed them to screen the small molecule libraries, identifying well‐aligned molecules with these pharmacophore features. Physics‐based molecular simulations were conducted on these molecules. Post‐processing molecular dynamics (MD) trajectory analyses, including binding free energy analyses, fragment‐based drug design, as well as steered MD (sMD) simulations, led to the identification of 19 hit candidate compounds exhibiting highly promising results. To assess their potential, these hit compounds were compared to positive control compounds (DB36, CVN) known for their impact on the OX40–OX40L interaction. This comparative analysis underscores the potential effects of the identified potential hit compounds.