JaLCDOI 10.18926/AMO/31960
FullText URL fulltext.pdf
Author Huang, Jian| Wu, Lijun| Tashiro, Shin-ichi| Onodera, Satoshi| Ikejima, Takashi|
Abstract <p>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.</p>
Keywords oridonin caspase Bax/Bcl-2 MAPK I?B
Amo Type Original Article
Published Date 2005-12
Publication Title Acta Medica Okayama
Volume volume59
Issue issue6
Publisher Okayama University Medical School
Start Page 261
End Page 270
ISSN 0386-300X
NCID AA00508441
Content Type Journal Article
language 英語
File Version publisher
Refereed True
PubMed ID 16418769
Web of Sience KeyUT 000234176600004
JaLCDOI 10.18926/AMO/31959
FullText URL fulltext.pdf
Author Huang, Jian| Wu, Lijun| Tashiro, Shin-ichi| Onodera, Satoshi| Ikejima, Takashi|
Abstract <p>We investigated the mechanism of the pan-caspase inhibitor z-VAD-fmk's augmentation of TNFalpha-induced L929 cell death and found this mechanism differs from that of TNFalpha-induced L929 cell death. In the presence of 20 ng/ml TNFalpha, z-VAD-fmk initiated apoptosis and necrosis in the majority of L929 cells as measured by an agarose gel electrophoresis and lactate dehydrogenase(LDH)activity based assay. Mitochondrial permeability transition (MPT) inhibitor (cyclosporine A) effectively inhibited z-VAD-fmk-augmented cell death. In addition, z-VAD-fmk plus TNFalpha increased Bax expression without affecting Bcl-2 and cytochrome expression. Western-blot analysis showed that z-VAD-fmk plus TNFalpha caused persistent JNK activation and ERK inactivation. Poly(ADP-ribose) polymerase (PARP) inhibitor (DPQ) effectively reversed the cell death which was augmented by z-VAD-fmk, and z-VAD-fmk plus TNFalpha also caused PARP cleavage to an 85 KDa fragment. These results indicate that in the presence of TNFalpha, z-VAD-fmk further augments cell death which requires the mitochondrial permeability transition and the JNK activation. However, we did not detect the changes in cytochrome c expression and the participation of caspase-9 in this process, suggesting that there might exist an unknown signal pathway(s) from the mitochondria to the downstream protein PARP, which is cleaved in a caspase-independent manner.</p>
Keywords TNF? caspase Bax/Bcl-2 MAPK PARP
Amo Type Original Article
Published Date 2005-12
Publication Title Acta Medica Okayama
Volume volume59
Issue issue6
Publisher Okayama University Medical School
Start Page 253
End Page 260
ISSN 0386-300X
NCID AA00508441
Content Type Journal Article
language 英語
File Version publisher
Refereed True
PubMed ID 16418768
Web of Sience KeyUT 000234176600003