Targeting FGFR2 with natural products: Discovery and experimental validation of torosanin as a potent and selective therapeutic candidate for gallbladder cancer.

Gallbladder cancer (GBC) is a highly aggressive malignancy of the biliary tract with limited treatment options and poor prognosis. Fibroblast Growth Factor Receptor 2 (FGFR2) alterations play a crucial role in GBC progression, driving oncogenic signaling pathways and tumor aggressiveness, making it a promising therapeutic target. This study aims to identify potent natural product-derived inhibitors of FGFR2 by screening African natural product databases (EANPDB, NANPDB, SANCDB) using virtual drug screening, molecular dynamics simulation and binding free energy calculation. Molecular screening identified the top six lead compounds Knipholone (-8.3801 kcal/mol), Torosanin (-8.3014 kcal/mol), Myricetin (-10.477 kcal/mol), Quercetin (-10.228 kcal/mol), 3-O-Methylquercetin (-9.827 kcal/mol), and Rubrolide E (-8.320 kcal/mol) based on specificity and high docking scores. Furthermore, MD simulations confirmed the stability of all lead compounds in the FGFR2 binding pocket, with Torosanin showing the most stable binding (RMSD: 1.3 Å). Additionally, The binding free energy calculations further supported the strong interactions, with values recorded as -29.3823 kcal/mol for the control, -38.3712 kcal/mol for Knipholone, -46.6771 kcal/mol for Torosanin, -30.9168 kcal/mol for Myricetin, -37.6727 kcal/mol for Quercetin, -29.7134 kcal/mol for Methylquercetin, and - 21.3565 kcal/mol for Rubrolide E. Moreover, ADMET evaluation showed all compounds met Lipinski's drug-likeness criteria, with favorable solubility, permeability, and minimal toxicity. The in vitro validation revealed that Torosanin selectively inhibits FGFR2-driven gallbladder cancer cell proliferation by inducing apoptosis and suppressing the FGFR2-ERK/AKT signaling pathway. Its additional anti-migratory effects highlight its potential as a targeted therapeutic agent for FGFR2-positive GBC. In conclusion, this study identified promising FGFR2 inhibitors from natural products, with Torosanin emerging as the most potent candidate. These findings provide a foundation for further clinical validation, potentially leading to novel FGFR2-targeted therapies for GBC.