Cantharidin induces G2/M phase arrest by inhibition of Cdc25c and cyclin A and triggers apoptosis through reactive oxygen species and the mitochondria-dependent pathways of A375-S2 human melanoma cells

Cantharidin (CT D), a component of natural mylabris (Mylabris phalerata Pallas) was reported to have high cytotoxicity in many human cancer cell lines. However, it was not reported to affect human melanoma A375-S2 cells. In the present study, we found that CT D induced cell morphological changes and decreased the percentage of viable cells and induced G2/M phase arrest and induction of apoptosis in A375-S2 cells. Results also showed that CT D induced the generation of reactive oxygen species (RO S) and Ca2+ and decreased mitochondria membrane potential and lead to the release of cytochrome c, AIF and Endo G. Further investigation revealed that CT D induced A375-S2 cells with an increase of caspase activation and caspase-dependent apoptotic proteins to trigger correlated pathway mechanisms according to western blotting results. Western blotting was used for examining the changes of G2/M phase arrest and apoptosis-associated protein expression and confocal laser microscopy was used to examine the translocation apoptosis-associated protein. Results showed that CT D increased the protein expression of caspase.3,.8 and.9, cytochrome c, Bax, Bid, Endo G and AIF but inhibited the levels of Bcl-2 and Bcl-x. CT D induced ER stress-associated protein expression such as GR P78, IRE 1β, ATF 6α and caspase-12. Based on those observations, we suggest that CT D may have potential as a novel anti-cancer agent for the treatment of skin cancer.