Computational Discovery of Selective Carbonic Anhydrase IX (CA IX) Inhibitors via Pharmacophore Modeling and Molecular Simulations for Cancer Therapy

Carbonic anhydrase IX (CA IX) is a transmembrane metalloenzyme that is increased in tumor cells under hypoxia and plays an important role in solid tumor acidification. It is a marker of tumor hypoxia and a prognostic factor in human malignancies. Given the critical role of CA IX and their over expression in many cancer tissues, they have emerged as a promising target for developing novel anticancer therapeutics. In this study we designed a pharmacophore model based on known inhibitors to screen small compound libraries to discover potential inhibitors of CA IX. Molecular docking experiments discovered that four compounds ZINC613262012, ZINC427910039, ZINC616453231, and DB00482 exhibited a strong binding affinity towards CA IX, mimicking the interaction pattern similar to native inhibitors. Molecular dynamics simulations and an MM-PBSA analysis revealed ZINC613262012, ZINC427910039, and DB00482 as the most potential and stable inhibitors with the binding free energies -10.92, -18.77, and -12.29 kcal/mol, respectively. In addition, DFT-based analyses supported their favorable electronic properties, further validating their potential as CA IX inhibitors. These three hits demonstrated a greater stability and compactness relative to the known inhibitors, suggesting these might be used CA IX inhibitors to treat tumors.