Regorafenib, a multitargeted kinase inhibitor, inhibits enterovirus 71 infection by suppressing the MAPK pathway

Enterovirus 71 (EV71), one of the major pathogens that causes hand, foot, and mouth disease (HFMD), has seriously threatened the health and safety of young children. Vaccines for EV71 C4 are currently available; however, there are no licensed direct antiviral agents for severe cases. In this study, we demonstrate that regorafenib, a clinically approved multitargeted kinase inhibitor with anticancer applications, exhibits potent antiviral activity against EV71 and demonstrates broad-spectrum efficacy against multiple human enteroviruses. In an EV71-infected murine model, oral administration of regorafenib at doses of 1.25 or 2.5 mg/kg/day significantly alleviated infection-associated symptoms and reduced viral loads in key organs. Mechanistic investigations revealed that regorafenib inhibited EV71 by suppressing the phosphorylation of MAPK/ERK kinase (MEK) and extracellular signal-regulated kinase (ERK) in the mitogen-activated protein kinase (MAPK) pathway, a viral-induced signaling cascade critical for viral pathogenesis. Additionally, molecular docking studies predicted regorafenib's binding to the EV71 capsid protein VP1, suggesting a potential structural basis for its antiviral mechanism. In summary, our findings establish that regorafenib exhibits inhibitory activity against EV71 and warrants further preclinical evaluation as a candidate lead compound.