Abstract
The interaction between molecular targeted therapy drugs and target proteins is crucial with regard to the drugs' anti-tumor effects. Electric fields can change the structure of proteins, which determines the interaction between drugs and proteins. However, the regulation of the interaction between drugs and target proteins and the anti-tumor effects of electric fields have not been studied thoroughly. Here, we explored how electric fields enhance the inhibition of regorafenib with regard to the activity, invasion, and metastasis of hepatocellular carcinoma cells. We found that electric fields lead to an increase in the normal (adhesion) and transverse (friction) interaction forces between regorafenib and VEGFR2. In single molecule pair interactions, there are changes in specific and nonspecific forces. Hydrogen bonds, hydrophobic interactions, and van der Waals forces are the main influencing factors. Importantly, the increase in the adhesion force and friction force between regorafenib and VEGFR2 caused by electric fields is related to the activity and migration ability of hepatocellular carcinoma cells. The morphological changes in VEGFR2 prove that electric fields regulate protein conformation. Overall, our work proves the drug-protein mechanical mechanism by which electric fields enhance the anti-tumor effect of regorafenib and provides insights into the application of electric fields in clinical tumor treatment.