The role of Ca+2 on rhein-induced apoptosis in human cervical cancer Ca ski cells

Apoptosisinducedbyrhein,anactivecomponentof senna,hasbeenreportedinvarioushumancancercells,however, itsmolecularmechanismsarenotpreciselyknown.Inthisstudy, the mechanisms of apoptosis by which rhein acts on human cervical cancer Ca Ski cells were examined . Flow cytometric analysis demonstrated that rhein induced the abrogation of mitochondrialmembranepotential(MMP)andcleavageofBid protein.RheinalsoinducedanincreaseinthelevelsofFas,p53, p21andBax,butadecreaseinthelevelofBcl-2.Theactivitiesof both caspase-8 and -9 were enhanced by rhein, promoting caspase-3 activation, leading to DNA fragmentation, thus , indicatingthatrhein-inducedapoptosisiscaspase-dependent.In addition, rhein induced an increase in the level of cytoplasmic Ca 2+ , which was inhibited by BAPTA (a calcium chelator).