Cytochrome c release from oridonin-treated apoptotic A375-S2 cells is dependent on p53 and extracellular signal-regulated kinase activation.
We have reported that oridonin isolated from Rabdosia rubescens induces apoptosis of human melanoma A375-S2 cells within 12 h. In this study, TUNEL assay and flow cytometric analysis also indicate that one of the causes of A375-S2 cell death induced by oridonin was apoptosis. The cell death was preceded by the release of cytochrome c from the mitochondria. Twelve hours after treatment with oridonin, the ratio of Bax/Bcl-xL protein expression was increased and release of cytochrome c was decreased by an extracellular signal-regulated kinase (ERK) MAPK inhibitor (PD98059) and a phosphoinositide 3-kinases (PI3-K) inhibitor (wortmannin). A mitochondrial permeability transition (MPT) inhibitor, decylubiquinone, suppressed the release of cytochrome c without affecting Bax expression. The activation of p53 by oridonin was also blocked by wortmannin. In addtion, PD98059 and wortmannin significantly decreased oridonin-induced DNA fragmentation, but the p38 MAPK inhibitor (SB203580) did not after DNA fragmentation. Oridonin induced A375-S2 cell apoptosis by activating parallel p53 and ERK pathways, increasing the ratio of Bax/Bcl-xL protein expression, and promoting the release of cytochrome c into the cytosol, resulting in apoptotic cell death.
Zhang
Chun-Ling
CL
China-Japan Research Institute of Medical and Pharmaceutical Sciences, Shenyang Pharmaceutical University, Shenyang 110016, China.
Wu
Li-Jun
LJ
Zuo
Hai-Jun
HJ
Tashiro
Shin-ichi
S
Onodera
Satoshi
S
Ikejima
Takashi
T
D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology; D045744:Cell Line, Tumor; D045304:Cytochromes c / Q000378:metabolism*; D053938:DNA Fragmentation / Q000187:drug effects / Q000502:physiology; D004224:Diterpenes / Q000737:chemistry / Q000494:pharmacology*; D045786:Diterpenes, Kaurane; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D006801:Humans; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
D004224:Diterpenes; D045786:Diterpenes, Kaurane; D016159:Tumor Suppressor Protein p53; C011959:oridonin; D045304:Cytochromes c; D048049:Extracellular Signal-Regulated MAP Kinases