A comparison of the signal pathways between the TNF alpha- and oridonin-induced murine L929 fibrosarcoma cell death.
Oridonin, an active component isolated from Rabdosia rubescences, has been reported to have antitumor effects. In this study, we compared the signal transduction pathways between TNFalpha-and oridonin-induced L929 cell death. Oridonin and TNFalpha initiated apoptotic morphologic changes, but DNA fragmentation was found in TNFalpha-treated L929 cells but not in oridonin-treated ones. The pan-caspase inhibitor (z-VAD-fmk), caspase-8 inhibitor (z-IETD-fmk) and caspase-3 inhibitor (z-DEVD-fmk) augmented oridonin-and TNFalpha-induced cell death. However, the caspase-9 inhibitor (z-LEHD-fmk) only increased oridonin-induced L929 cell death. Moreover, poly (ADPribose) polymerase (PARP) was cleaved in oridonin-treated L929 cells but not in the TNFalpha-treated groups, and the caspase-3 inhibitor (z-DEVD-fmk) failed to inhibit PARP cleavage. These results showed that only oridonin-induced L929 cell death required PARP degradation in a caspase-3 independent manner. In addition, oridonin increased the ratio of Bax/Bcl-2 protein expression, but TNFalpha did not. TNFalpha induced p38 and ERK activation, whereas oridonin triggered only ERK activation. We also investigated the effect of oridonin on intracellular TNFalpha expression, and found that oridonin augmented endogenous pro-TNFalpha expression and its upstream protein IkB phosphorylation. These results indicated that although oridonin promoted endogenous pro-TNFalpha expression, a great difference existed between the signal pathways through which TNFalpha-and oridonin-induced cell death.
Huang
Jian
J
China-Japan Research Institute of Medical and Pharmaceutical Sciences, Shenyang Pharmaceutical University, PR China.
Wu
Lijun
L
Tashiro
Shin-Ichi
S
Onodera
Satoshi
S
Ikejima
Takashi
T
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D045744:Cell Line, Tumor; D004224:Diterpenes / Q000494:pharmacology*; D045786:Diterpenes, Kaurane; D048049:Extracellular Signal-Regulated MAP Kinases / Q000502:physiology; D005354:Fibrosarcoma / Q000473:pathology*; D051379:Mice; D011065:Poly(ADP-ribose) Polymerases / Q000502:physiology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D051028:bcl-2-Associated X Protein / Q000502:physiology; D048051:p38 Mitogen-Activated Protein Kinases / Q000502:physiology
D004224:Diterpenes; D045786:Diterpenes, Kaurane; D019253:Proto-Oncogene Proteins c-bcl-2; D014409:Tumor Necrosis Factor-alpha; D051028:bcl-2-Associated X Protein; C011959:oridonin; D011065:Poly(ADP-ribose) Polymerases; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases