Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
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Target Concepts:
Gene/Protein
Disease
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Enzyme
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Query: EC:3.4.22.61 (
caspase-8
)
6,833
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Primary effusion lymphomas (PELs) characterized by infection with the Kaposi's sarcoma herpesvirus (KSHV; also called human herpesvirus 8) depend on the expression of the viral FADD-like interleukin-1-beta-converting enzyme (FLICE)/
caspase-8
-inhibitory protein (vFLIP) for their survival. This effect is achieved by activation of the transcription factor nuclear factor-kappaB (NF-kappaB). Tumour necrosis factor (TNF) receptor-associated factors (TRAFs) are direct mediators of NF-kappaB signalling by TNF family receptors and the Epstein-Barr virus oncoprotein latent membrane protein 1 and so we assessed the role of TRAFs in signalling by vFLIP. Here, we report the identification of a TRAF-interacting motif (PYQLT) in vFLIP, which is not present in other FLIP molecules. We show that vFLIP directly binds to TRAF2 in vitro and in
PEL
cells. TRAF2 and TRAF3 are required for induction of NF-kappaB and associated cell survival, as well as Jun amino-terminal kinase phosphorylation by vFLIP, whereas TRAF1, TRAF5 and TRAF6 are dispensable. Mutations in the P93 or Q95 amino acids within the TRAF-interacting motif of vFLIP abolish its ability to bind to TRAF2 and to signal to NF-kappaB. TRAF2, but not TRAF3, mediates the association of vFLIP with the IkappaB kinase complex. These data indicate that vFLIP uses TRAF2 and TRAF3 for signalling to NF-kappaB, which is crucial for KSHV-associated lymphomagenesis.
...
PMID:The KSHV oncoprotein vFLIP contains a TRAF-interacting motif and requires TRAF2 and TRAF3 for signalling. 1631 16
Primary effusion lymphoma
(
PEL
) is an incurable, aggressive B-cell malignancy that develops rapid resistance to conventional chemotherapy. In efforts to identify novel approaches to block proliferation of
PEL
cells, we found that sanguinarine, a natural compound isolated from the root plant Sanguinaria canadendid, inhibits cell proliferation and induces apoptosis in a dose-dependent manner in several
PEL
cell lines. Our data show that sanguinarine treatment of
PEL
cells results in up-regulation of death receptor 5 (DR5) expression via generation of reactive oxygen species (ROS) and causes activation of
caspase-8
and truncation of Bid (tBid). Subsequently, tBid translocates to the mitochondria causing conformational changes in Bax, leading to loss of mitochondrial membrane potential and release of cytochrome c to the cytosol. Sanguinarine-induced release of cytochrome c results in activation of caspase-9 and caspase-3 and poly(ADP-ribose) polymerase (PARP) cleavage, leading to induction of caspase-dependent apoptosis. In addition, we show that pretreatment of
PEL
cells with carbobenzoxy-Val-Ala-Asp-fluoromethylketone, a universal inhibitor of caspases, abrogates caspase and PARP activation and prevents cell death induced by sanguinarine. Moreover, treatment of
PEL
cells with sanguinarine down-regulates expression of inhibitor of apoptosis proteins (IAP). Finally, N-acetylcysteine, an inhibitor of ROS, inhibits sanguinarine-induced generation of ROS, up-regulation of DR5, Bax conformational changes, activation of caspase-3, and down-regulation of IAPs. Taken together, our findings suggest that sanguinarine is a potent inducer of apoptosis of
PEL
cells via up-regulation of DR5 and raise the possibility that this agent may be of value in the development of novel therapeutic approaches for the treatment of
PEL
.
...
PMID:Sanguinarine-dependent induction of apoptosis in primary effusion lymphoma cells. 1744 Jan 3
