Abstract: Objective To identify the target genes mediating anti-tumor effect of sesquiterpenoids from Cryptoporus volvatus and explore the possible mechanism using molecular docking and molecular dynamics simulation. Methods Based on the chemical structure of sesquiterpenes from C. volvatus, we explored the online reverse target finding websites PharmMapper, SEA, Target Hunter and related literature for preliminary prediction of possible anti-tumor targets. Discovery Studio 4.0 (Libdock function) and Maestro 12.3 were used to connect sesquiterpenes with the possible targets, and the potential targets were selected according to the scores. The interaction between the sesquiterpenes and the targets were analyzed using 2D interaction diagram, and the influence of different sesquiterpene skeletons on their activity was inferred based on their activity measurements in experiment. Kinetic simulation was performed for front-end protein sequence (1UNQ) of the Akt (protein kinase B) and for the complex formed by 1UNQ and compound 4 (which had the best cytotoxic activity in vitro) in its optimal conformation, and the root mean square deviation (RMSD) value and root mean square float (RMSF) value of the complex and 1UNQ were measured to evaluate the stability of the binding of compound 4 to the target. Results The sesquiterpenes showed optimal binding with 1UNQ. Analysis of 2D interaction diagram suggested that the hydrogen bonding and electrostatic force were the most important forces mediating the interaction between the sesquiterpenes and 1UNQ. Analysis of the optimal 3D conformation showed that for different sesquiterpenes, a slight change of the molecular framework produced a steric hindrance effect and caused changes in their bioactivity. Kinetic simulation showed that the complex formed by compound 4 and1UNQ had a lower RMSD than the target pure protein sequence, indicating that compound 4 could stably bind to 1UNQ. The anti-tumor effect of the sesquiterpenoids from C. volvatus was associated with their ability to cause Lys-14 acetylation, which blocks Akt binding to the downstream PIP3 and thus affects the proliferation of tumor cells. Conclusion 1UNQ is the target of sesquiterpenoids from C. volvatus, which affects the proliferation of tumor cells by acetylating Lys-14.

Key words: molecular docking; Cryptoporus volvatus; sesquiterpenoids; anti-tumor mechanism