Refining Potent STAT3 Inhibitor Structure Through Molecular Docking

Refining Potent STAT3 Inhibitor Structure Through Molecular Docking

Alvin Sherman Library

Signal Transducer and Activator of Transcription 3 (STAT3) plays a central role in signaling regulation in many cancers including glioblastoma. Normally, STAT3 is activated by the presence of ligand. In cancer cells, STAT3 is constitutively activated, making it a therapeutic target. STAT3 inhibitors currently used in clinical trials act by targeting upstream activators of STAT3. However, cancer cells bypass these pathways, activating STAT3 through receptor-pathway independent mechanism. Therefore, there is a need for inhibitors to directly target and inhibit STAT3, therefore blocking its function. Nitro groups (-NO₂) are being investigated as potential anti-cancer compounds. In cellular studies, IX-11 has been found to be the most effective molecule in inhibiting glioblastoma cell growth. Here we present an investigation of several STAT3 inhibitor variants derived from the parent compound IX-11. Using SwissDock with standardized AutoDock Vina parameters, each new potential inhibitor was docked with a modified STAT3 protein (PDBID: 1BG1). Systematic modification of meta nitro groups, central cyclohexanone core, and halogen substituents resulted in a variety of molecules. Replacement of nitro groups with N-rich heteroaromatic rings improved predicted binding affinity through enhanced hydrogen ponding and π-stacking interactions. Addition of an N-acetyl group to the cyclohexanone ring further stabilized the complex, whereas full ring removal reduced predicted affinity. Fluorine proved consistently superior to chlorine or bromine as a halogen substituent. The top-performing IX-11 derivate featured both oxadiazole substitution and an acetamide group on the central ring. Together, these findings illustrate how collaborative docking studies can general meaningful structure-activity insights for STAT3 SH2 inhibition.