Objective: To investigate the effect of cantharidin on proliferation

apoptosis and MAPK signaling in hepatocellular carcinoma HepG2 cells. Method: IncuCyteTM ZOOM-based proliferation assay and clonogenic assay were used to assess the inhibitory effect of cantharidin (CTD) on HepG2 cells. Flow cytometry was used to define the effect of CTD on apoptosis. Western blot was used to monitor the changes in Caspase-3

poly adeno-sine diphosphate ribose polymerase (PARP)

extraeellular-signalregulatedki-nase (ERK1/2) and proteinkinase B (Akt) phosphorylation after CTD treatment. Finally

ERK1/2 inhibitor (PD98059)

and Akt inhibitor (Wortmannin) were used to assess the potential effect of ERK1/2 and Akt on the inhibitory and/or pro-apoptotic effect of CTD. Result: CTD at 2.5 μmol·L-1 significantly inhibited the growth of HepG2

but did not significantly affect cell survival. However

CTD at 5 μmol·L-1 resulted in not only most a complete inhibitory effect on growth

but also a significant apoptosis rate (40.4%). Western blot result showed that 5 μmol·L-1 of CTD decreased pro Caspase-3 expression and increased cleaved PARP expression in HepG2.Besides

CTD promoted the phosphorylation of ERK

but not Akt. Conclusion: CTD exhibited a potent growth inhibitory (cytostatic) effect at 2.5 μmol·L-1

but could show a strong pro-apoptotic (cytotoxic) effect at 5 μmol·L-1 for HepG2 cells. Therefore

the study reveals a potent cytostatic effect of CTD and a certain cytotoxic potency

suggesting that the cytostatic effect is an important anticancer mechanism.