Girdin silencing enhances mebendazole-mediated anticancer activity: a combinatorial therapeutic strategy for ovarian cancer.

Ovarian cancer is among the deadliest gynecological malignancies due to its aggressive nature and limited treatment options. Mebendazole (MBZ), a known antiparasitic drug, has shown anticancer activity in several cancer types, though its mechanisms, particularly in ovarian cancer, remain unclear. Girdin (CCDC88A), a key regulator of Akt signaling and cancer cell invasion, represents a promising therapeutic target. This study explores the combined effect of MBZ and Girdin knockdown in ovarian cancer cell lines OVCAR3 and OAW42. Cells were treated with MBZ and transfected with Girdin-targeting siRNA, either individually or in combination. Biochemical assays (migration, invasion, and clonogenicity) and immunoblotting were used to assess the molecular mechanism and protein expression. Computational techniques, including homology modeling, molecular docking, structural interaction fingerprinting (SIFt), and density functional theory (DFT), were employed to study MBZ-Girdin binding. In addition, protein-protein interaction (PPI) network analysis and KEGG pathway enrichment (visualized using Cytoscape) were conducted to understand broader molecular effects. Our results showed that both MBZ and Girdin knockdown significantly decreased Girdin levels, with the combination yielding a greater inhibitory effect. This dual approach led to marked suppression of ovarian cancer cell migration, invasion, and colony formation. Docking studies confirmed stable MBZ binding to Girdin's catalytic domain, supported by favorable binding energies and molecular interactions. This is the first study to demonstrate that MBZ's anticancer efficacy is significantly enhanced by Girdin silencing, implicating the modulation of critical oncogenic pathways.