Exploring the pharmacological mechanisms of resibufogenin in castration-resistant prostate cancer via network pharmacology and experimental validation

Background: Resibufogenin (RBG) has shown anti-tumor effects in many cancers, but its role and mechanism in castration-resistant prostate cancer (CRPC) are still unclear. Methods: We screened a library of reactive oxygen species (ROS)-related compounds and selected RBG for further study. We evaluated its anti-proliferative effects in PC3 and RM1 cells by CCK-8 assay, colony formation assay, ROS detection, and Western blot. We explored the possible targets and pathways of RBG in PCa by network pharmacology and clinical data analysis. We then studied the key candidate targets by molecular docking and molecular dynamics (MD) simulation. Results: experiments showed that RBG inhibited the proliferation and colony formation of PC3 and RM1 cells in a dose-dependent and time-dependent manner. RBG also increased intracellular ROS levels and changed the expression of apoptosis-related proteins. Network pharmacology and KEGG analysis showed that the MAPK signaling pathway may play an important role in the action of RBG in prostate cancer. Clinical data analysis further narrowed the possible targets to BRAF and SRC. Molecular docking showed that RBG had stronger predicted binding to BRAF than to SRC. MD simulation supported the structural stability of the BRAF-RBG complex, and free energy landscape analysis further suggested the presence of a relatively stable conformational state during the simulation. Conclusions: This study suggests that RBG inhibits malignant phenotypes of CRPC cells and may exert its anti-tumor effects in part through interaction with BRAF and modulation of the MAPK signaling pathway. These findings support RBG as a promising candidate for further study in prostate cancer treatment.