Design, synthesis, and antitumor activity of novel Flavokawain A derivatives by suppressing LRPPRC-YBX1-RPN1 cascade

Natural Flavokawain A (FKA) demonstrates notable anti-tumor activity. In this study, a novel sulfonamide derivative, designated as FKA-9i, was meticulously designed and synthesized. This compound effectively inhibits cancer cell proliferation and tumor growth by inducing cancer cell cycle arrest, apoptosis, and mitochondrial dysfunction, manifested as the inhibition of oxidative phosphorylation and the accumulation of reactive oxygen species, without discernible toxicity. Mechanistic studies integrating small molecule pull-down coupled with proteomics and surface plasmon resonance techniques initially verified that FKA-9i directly binds to the target proteins leucine-rich PPR motif-containing protein (LRPPRC), Y-box binding protein 1 (YBX1), and ribophorin I (RPN1), reducing their interactions and stability. Further experiments confirmed that these are FKA-9i direct targets, as the anti-tumor activity of FKA-9i was significantly attenuated following LRPPRC, YBX1, and RPN1 knockdown. RNA sequencing and pathway analysis revealed that FKA-9i impede cancer progression via LRPPRC-YBX1-RPN1 mediated MAPK signaling pathway. Moreover, FKA-9i exhibits a synergistic enhancement effect when combined with chemotherapeutic drugs, YBX1 and RPN1 inhibitors, as well as drugs targeting the glycolysis pathway. This study firmly establishes FKA-9i as an anti-tumor leading compound by targeting the LRPPRC-YBX1-RPN1 mediated MAPK regulatory network, offering a novel strategy to surmount the clinical translation hurdles of natural flavonoids.