Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.22.61 (caspase-8)
 6,833 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Various human colon cancer cell lines tested in vitro differed significantly in susceptibility to growth inhibition of recombinant human interferon-beta (rHuIFN-beta). Two p53-mutant lines, COH and CC-M2, derived from high-grade colon adenocarcinoma, showed signs of apoptosis after treatment with 250 IU/ml of HuIFN- beta in the culture medium. The similarly p53-mutated HT-29 line from a grade I adenocarcinoma showed no apoptosis, however, and only cell cycle G1/G0 or S phase retardation with 1000 IU/ml HuIFN-beta. After HuIFN-beta exposure, COH and CC-M2 cells showed increased levels of Fas and FasL proteins, alteration of mitochondrial membrane potential, and activation of caspase-9, caspase-8, and caspase-3 in a time-dependent manner. Treatment of COH and CC-M2 cells with anti-FasL antibodies or rFas/Fc fusion protein, however, could not prevent the apoptosis induced by HuIFN-beta. In contrast, cell-permeable specific inhibitors of the three caspases could inhibit the DNA fragmentation and cell death but not the mitochondrial membrane potential changes. Treatment with mitochondria-stabilizing reagents could significantly abrogate the apoptosis and caspase activation induced by HuIFN-beta. These results suggest that in COH and CC-M2 colon cancer cell lines, HuIFN-beta induces apoptosis mainly through mitochondrial membrane alteration and subsequent activation of the caspase cascade pathway, but not by the Fas/FasL interaction or the p53-dependent apoptotic mechanism.
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PMID:IFN-beta induces caspase-mediated apoptosis by disrupting mitochondria in human advanced stage colon cancer cell lines. 1514 69

The cytokine interleukin (IL)-1beta is a key mediator of the inflammatory response and has been implicated in the pathophysiology of acute and chronic inflammation. IL-1beta is synthesized in response to many stimuli as an inactive pro-IL-1beta precursor protein that is further processed by caspase-1 into mature IL-1beta, which is the secreted biologically active form of the cytokine. Although stimulation of membrane-bound Toll-like receptors (TLRs) up-regulates pro-IL-1beta expression, activation of caspase-1 is believed to be mainly initiated by cytosolic Nod-like receptors. In this study, we show that polyinosinic:polycytidylic acid (poly[I:C]) and lipopolysaccharide stimulation of macrophages induces pro-IL-1beta processing via a Toll/IL-1R domain-containing adaptor-inducing interferon-beta-dependent signaling pathway that is initiated by TLR3 and TLR4, respectively. Ribonucleic acid interference (RNAi)-mediated knockdown of the intracellular receptors NALP3 or MDA5 did not affect poly(I:C)-induced pro-IL-1beta processing. Surprisingly, poly(I:C)- and LPS-induced pro-IL-1beta processing still occurred in caspase-1-deficient cells. In contrast, pro-IL-1beta processing was inhibited by caspase-8 peptide inhibitors, CrmA or vFLIP expression, and caspase-8 knockdown via RNAi, indicating an essential role for caspase-8. Moreover, recombinant caspase-8 was able to cleave pro-IL-1beta in vitro at exactly the same site as caspase-1. These results implicate a novel role for caspase-8 in the production of biologically active IL-1beta in response to TLR3 and TLR4 stimulation.
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PMID:Stimulation of Toll-like receptor 3 and 4 induces interleukin-1beta maturation by caspase-8. 1872 21

Detachment of adherent epithelial cells from the extracellular matrix induces apoptosis, a process known as anoikis. We have shown that DAP3 is critical for anoikis induction. However, the mechanism for anoikis induction mediated by DAP3 is still unclear. Here, we show that interferon-beta promoter stimulator 1 (IPS-1) binds DAP3 and induces anoikis by caspase activation. Recently, IPS-1 has been shown to be critical for antiviral immune responses, although there has been no report of its function in apoptosis induction. We show that overexpression of IPS-1 induces apoptosis by activation of caspase-3, -8, and -9. In addition, IPS-1 knockout mouse embryonic fibroblasts were shown to be resistant to anoikis. Interestingly, IPS-1 expression, recruitment of caspase-8 to IPS-1, and caspase-8 activation were induced after cell detachment. Furthermore, DAP3-mediated anoikis induction was inhibited by knockdown of IPS-1 expression. Therefore, we elucidated a novel function of IPS-1 for anoikis induction by caspase-8 activation.
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PMID:IPS-1 is crucial for DAP3-mediated anoikis induction by caspase-8 activation. 1964 11