Oridonin induces apoptosis of HeLa cells via altering expression of Bcl-2 ／ Bax and activating caspase-3 ／ ICAD pathway

INTRODUCTIONHerbal medicine, Donglingcao (rabdosiarubescens), has been traditionally used in China for thetreatment of various diseases such as leukemia.Oridonin (Fig 1) is a diterpenoid compound isolated fromRabdosia rubescens (hemsl). It has various pharmaco-logical and physiological effects such as anti-inflammation, anti-bacteria, anti-tumor1-3] and has beenused for the treatment of human cancers, especiallyFig 1. Chemical structure of oridonin.esophageal carcinoma4]. This comp…

Oridonin induces apoptosis of HeLa cells via altering expression of Bcl-2/Bax and activating caspase-3/ICAD pathway

To study the mechanisms by which oridonin inhibited HeLa cell growth in vitro. METHODS: Viability of oridonin-induced HeLa cells was measured by MTT assay. Apoptotic cells with condensed nuclei were visualized by phase contrast microscopy. Nucleosomal DNA fragmentation was assayed by agarose gel electrophoresis.Caspase activity was assayed using fluorometric protease assay. ICAD, Bcl-2, and Bax proteins expression were detected by Western blot analysis. RESULTS: Oridonin induced oligonucleosomal fragmentation of DNA and increased caspase-3 activity, on the other hand, reduced the expression of inhibitor of caspase-3-activated DNase (ICAD), a caspase-3 substrate, at 12 h in HeLa cells. Oridonin-induced DNA fragmentation, caspase-3 activation and down-regulation of ICAD expression were effectively inlfibited by a caspase-3 inhibitor, z-DEVD-fmk (z-Asp-Glu-Val-Asp-fmk). However, pretreatment with an inhibitor ofpoly (ADP-ribose) polymerase (PARP), 3, 4-dihydro-5-4-(1-piperidinyl)butoxy]-l(2H)-isoquinolinone (DPQ), did not suppress oridonin-induced HeLa cell death. In addition, oridonin-induced apoptosis was associated with an increase in the expression of the apoptosis inducer Bax, and a significant reduction in expression of the apoptosis suppressor Bcl-2 in mitochondria. CONCLUSION:Oridonin induces HeLa cells apoptosis by altering balance of Bcl-2 and Bax protein expression and activation of caspase-3/ICAD pathway.