First total synthesis,antitumor evaluation and target identification of mornaphthoate E:A new tubulin inhibitor template acting on PI3K/Akt signaling pathway

Mornaphthoate E(MPE)is a prenylated naphthoic acid methyl ester isolated from the roots of a famous Chinese medicinal plant Morinda officinalis and shows remarkable cytotoxicity against several human tumor cell lines.In the current project,the first total synthesis of(±)-MPE was achieved in seven steps and 5.6%overall yield.Then the in vitro anti-tumor activity of MPE was first assessed for both enantiomers in two breast cancer cells,with the levoisomer exerting slightly better potency.The in vivo anti-tumor effect was further verified by applying the racemate in an orthotopic autograft mouse model.Notably,MPE exerted promising anti-metastasis activity both in vitro and in vivo and showed no obvious toxicity on mice at the therapeutic dosage.Mechanistic investigations demonstrated that MPE acted as a tubulin polymerization stabilizer and disturbed the dynamic equilibrium of microtubules via regulating PI3K/Akt signaling.In conclusion,our work has provided a new chemical template for the future design and development of next-generation tubulin-targeting chemotherapies.