Viola plant cyclotide vigno 5 induces mitochondria-mediated apoptosis via cytochrome C release and caspases activation in cervical cancer cells

Cyclotides describe a unique cyclic peptide family that displays a broad range of biological activities including uterotonic, anti -bacteria, anti -cancer and anti -HIV. The vigno cyclotides consist of vigno 1-10 were reported recently from Viola ignobilis. In the present study, we examined the effects of vigno 5, a natural cyclopeptide from V. ignobilis, on cervical cancer cells and the underlying mechanisms. We found that vigno 5 -treated Hela cells were killed off by apoptosis in a dose -dependent manner within 24 h, and were characterized by the appearance of nuclear shrinkage, cleavage of poly (ADP -ribose) polymerase (PARP) and DNA fragmentation. The mitochondrial pathway of apoptosis revealed that cytochrome C is released from mitochondria to cytosol, associated with the activation of caspase-9 and -3, and the cleavage of poly (ADP -ribose) polymerase (PARP). Overall, the results indicate that vigno 5 induces apoptosis in part via the mitochondrial pathway, which is associated with a release of cytochrome C and elevated activity of caspase-9 and -3 in Hela cells. (C) 2016 Elsevier B.V. All rights reserved