Background: Cordycepin is a small molecule from medicinal mushroom Cordyceps,
which has been reported for anticancer properties.
Objective: In this study, we have focused on the investigation of cordycepin effect on cervical cancer
cells with further clarification of possible molecular mechanism.
Method: We have used cell viability and cell counting assay for cytotoxic effect of cordycepin, flow
cytometric assay of apoptosis and cell cycle, and quantitative PCR (qPCR) and Western blotting for
the determination of target gene expression. Molecular docking and Molecular dynamics simulation
were used for in silico analysis of cordycepin affinity to target protein(s).
Results: Treatment of cordycepin controlled SiHa and HeLa cervical cancer cell growth, increased the
rate of their apoptosis, and interfered with cell cycle, specifically elongated S-phase. qPCR results indicated
that there was a downregulation of cell cycle proteins CDK-2, CYCLIN-A2 and CYCLIN-E1 in
mRNA level by cordycepin treatment but no significant change was observed in pro-apoptotic or antiapoptotic
proteins. The intracellular reactive oxygen species (ROS) level in cordycepin treated cells
was increased significantly, implying that apoptosis might be induced by ROS. Western blot analysis
confirmed significant decrease of Cdk-2 and mild decrease of Cyclin-E1 and Cyclin-A2 by cordycepin,
which might be responsible for regulating cell cycle. Molecular docking indicated high binding affinity
of cordycepin against Cdk-2. Molecular dynamics simulation further confirmed that the docked pose of
cordycepin-Cdk-2 complex remained within the binding pocket for 10 ns.
Conclusion: Our study suggests that cordycepin is effective against cervical cancer cells, and regulating
cell cycle via cell cycle proteins, especially downregulating Cdk-2, and inducing apoptosis by
generating ROS are among the mechanisms of anticancer activities of cordycepin.