Effect of delta-elemene on Hela cell lines by apoptosis induction

Abstract

This study was designed to investigate the apoptosis-inducing activity of delta-elemene on Hela cells in vitro. MTT assay and Hoechst 33258/PI fluorescence microscopy were used for this investigation. Apoptosis was further confirmed and quantified by DNA fragmentation ELISA, Annexin V (AnV) binding of externalized phosphatidylserine and the mitochondrial probe JC-1 using flow cytometry. Generation of reactive oxygen species (ROS) was detected using CM-H2DCFDA. Western blots analysis was performed using antibodies against the pro-caspase-3, or PRAP (Poly (ADP-ribose) polymerase). The results showed that delta-elemene exhibited a marked antiproliferative effect on Hela cells in dose- and time-dependent manners, and had little inhibition to normal human liver cell line WRL-68. It was demonstrated that delta-elemene was capable of inducing DNA fragmentation in a dose- and time-dependent manner. AnV positivity and the disturbance of the polarized mitochondrial transmembrane potential (Deltapsim) suggested that delta-elemene induced apoptotic death of Hela cells. Western blot analysis demonstrated that delta-elemene activated the caspase-signaling pathway, leading to the proteolysis conversion of pro-caspase-3 to activate caspase-3, and the subsequent cleavage of the caspase substrate PARP. Further, it was noted that the apoptotic effect of delta-elemene could be attenuated by L-Glutathione (GSH) or z-DEVD-fmk. It suggested that the increase in ROS generation might be involved in the mechanism of delta-elemene induced cell apoptosis.