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)

The present study demonstrates that 3,5,3'-tri-iodothyronine (T3) in physiological dose range inhibits tumor necrosis factor alpha(TNFalpha)/Fas-induced apoptosis in mouse hepatocytes. T3 pretreatment prevented Fas-induced early stage of apoptosis signs assessed by flow cytometry analysis of the annexin V positive cell population. T3 attenuated TNFalpha/Fas-induced cleavage of caspase-8 and DNA fragmentation. We found that T3 exerted its anti-apoptotic effects by mobilization of several non-genomic mechanisms independent of transcriptional activity. Inhibition of protein kinase A (PKA), extracellular signal-regulated kinase (ERK), and Na+/H+ exchanger blocked T3-dependent anti-apoptotic effects indicating an involvement of these intracellular targets into T3-induced signaling cascade. Furthermore, physiological concentrations of T3, but not reverse T3, caused increases in intracellular cAMP content and activated PKA. T3 markedly induced phosphorylation of ERK. We also detected T3-dependent intracellular alkalinization that abolished TNFalpha-induced acidification. PKA inhibitor KT-5720 blocked T3-induced activation of ERK and intracellular alkalinization confirming the upstream position of PKA signaling. We further detected that hepatocytes from hypothyroid mice are more sensitive to TNFalpha/Fas-induced apoptosis than euthyroid animals in vivo. Together, these findings imply that T3 triggers PKA- and ERK-regulated intracellular pathways capable of driving and ensuring hepatocytes survival in the presence of death receptor ligand-induced damage under chronic inflammatory conditions.
 ...
PMID:Anti-apoptotic effects of 3,5,3'-tri-iodothyronine in mouse hepatocytes. 1708 14

Nitric oxide (NO) is associated with many pathophysiology of the central nervous system including brain ischemia, neurodegeneration and inflammation. Epigallocatechin gallate (EGCG) is a major compound of green tea polyphenol that has shown the protective activity against neuronal diseases. This study examined the effect of EGCG on NO-induced cell death in PC12 cells. The administration of sodium nitroprusside (SNP), a NO donor, decreased the cell viability and induced apoptosis showing characterization such as cell shrinkage and chromatin condensation as well as subG1 fraction of cell cycles. EGCG inhibited the cytotoxicity and apoptotic morphogenic changes induced by SNP. EGCG attenuated the production of reactive oxygen species (ROS) by SNP, and ameliorated the SNP-induced Bax to Bcl-2 expression ratio leading to apoptosis. In addition, EGCG prevented the release of cytochrome c from the mitochondria into the cytosol as well as the upregulation of the voltage-dependent anion channel (VDAC), a cytochrome c releasing channel, in the mitochondria of SNP-treated cells. EGCG abrogated the activation of caspase-9, caspase-8 and caspase-3 induced by SNP. These results demonstrate that EGCG has a protective effect against SNP-induced apoptosis in PC12 cells by scavenging ROS and modulating the signal molecules associated with cytochrome c, caspases, VDAC and the Bcl-2 family. These findings suggest that EGCG might be a natural neuroprotective substance.
 ...
PMID:Epigallocatechin gallate inhibits nitric oxide-induced apoptosis in rat PC12 cells. 1711 66

Indole-3-acetic acid (IAA) activation by horseradish peroxidase (HRP) has been suggested as a new cancer therapy. Interestingly, we found that ultraviolet B UVB radiation also can activate IAA and produce free radicals in a dose-dependent manner. In this study, we attempted to identify the free radicals generated by UVB-irradiated IAA (IAAUVB), and to determine whether IAAUVB can induce the apoptosis of G361 human melanoma cells. Since IAA/HRP produces reactive oxygen species (ROS), we examined whether IAAUVB-generated radicals include ROS. Our results show that IAAUVB-induced free radical production is not inhibited by catalase, superoxide dismutase, or sodium formate, indicating that ROS are not generated by IAAUVB. On the other hand, IAAUVB caused lipid peroxidation, and this was blocked by Trolox, a water-soluble vitamin E derivative. Moreover, we found that IAAUVB caused apoptotic cell death and that this was inhibited by a low temperature. We further investigated IAAUVB-mediated apoptotic pathways, and found that IAAUVB causes caspase-8, Bid, caspase-3 activation, and poly (ADP-ribose) polymerase (PARP) cleavage. In addition, these apoptotic pathways were also blocked by low temperature. From these results, we propose that IAAUVB-induced free radicals cause human melanoma cell apoptosis via a death receptor-mediated apoptotic pathway.
 ...
PMID:Light-activated indole-3-acetic acid induces apoptosis in g361 human melanoma cells. 1714 72

Interest in TNF-related apoptosis-inducing ligand (TRAIL) as a cancer therapeutic has been high since its first description. Recently, the use of histone deacetylase inhibitors (HDACi) to treat cancer has progressed from the laboratory to the clinic, and the combination of HDACi and TRAIL is very powerful in killing human tumors. Using a panel of prostate tumor cell lines (ALVA-31, DU-145, and LNCaP) with varying TRAIL sensitivity, we examined their sensitization to a recombinant adenovirus encoding TRAIL (Ad5-TRAIL) by sodium butyrate and trichostatin A. HDACi treatment increased coxsackie-adenovirus receptor (CAR) expression, resulting in increased adenoviral infection, and increased TRAIL-mediated killing. In TRAIL-resistant DU-145 cells, HDAC inhibition also decreased protein kinase casein kinase (PKCK) 2 activity, leading to caspase-2 activation. The importance of PKCK2 and caspase-2 in DU-145 sensitization was demonstrated with the PKCK-2-specific inhibitor, which enhanced Ad5-TRAIL-induced death, or the caspase-2-specific inhibitor, zVDVAD, which blocked Ad5-TRAIL-induced death. Thus, our data highlight the connection between HDAC inhibition of PKCK2 activity and tumor cell sensitivity to TRAIL-induced apoptosis. Specifically, HDAC inhibition leads to decreased PCKC2 activity, which is followed by caspase-2 activation and partial cleavage of caspase-8 that sensitizes the tumor cell to TRAIL.
 ...
PMID:Histone deacetylase inhibitors enhance Ad5-TRAIL killing of TRAIL-resistant prostate tumor cells through increased caspase-2 activity. 1719 89

To clarify the protective role of transforming growth factor (TGF)-beta for the intestinal epithelial injury in vivo, the effect of antibodies against TGF-beta on epithelial destruction and apoptosis was assessed in dextran sulfate sodium (DSS)-induced colitis by histological analysis of colonic sections, account of apoptotic epithelial cells. To evaluate the pathways of epithelial apoptosis, we analyzed the activities of caspases, the level of Fas and cellular FLICE-inhibitory protein (cFLIP) expression in epithelial cells. Apoptotic epithelial cells were increased prior to the onset of ulceration in DSS-induced colitis, and the neutralization of TGF-beta exacerbated epithelial apoptosis and histological damage score. The up-regulation of caspase-8 activity and Fas expression and reduced cFLIP expression were observed in intestinal epithelial cells from anti-TGF-beta antibody-treated mice. The present study revealed that suppression of TGF-beta deteriorated epithelial apoptosis, and the increase of apoptotic epithelial cells may amplify the inflammation in gut mucosa.
 ...
PMID:Blockade of TGF-beta accelerates mucosal destruction through epithelial cell apoptosis. 1756 May 53

The nonselective contact herbicide, paraquat (PQ), is a strong pneumotoxicant, especially due to its accumulation in the lung through a polyamine uptake system and to its capacity to induce redox cycling, leading to oxidative stress-related damage. In the present study, we aimed to investigate the occurrence of apoptotic events in the lungs of male Wistar rats, 24, 48, and 96 h after PQ exposure (25 mg/kg ip) as well as the putative healing effects provided by sodium salicylate [(NaSAL), 200 mg/kg ip] when administered 2 h after PQ. PQ exposure resulted in marked lung apoptosis, in a time-dependent manner, characterized by the "ladder-like" pattern of DNA observed through electrophoresis and by the presence of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling (TUNEL)-positive cells (TPC) as revealed by immunohistochemistry. The two main caspase cascades (the extrinsic receptor-mediated and the intrinsic mitochondria-mediated) and the expressions of p53 and activator protein-1 (AP-1) were also evaluated, to obtain an insight into apoptotic cellular signaling. PQ-exposed rats suffered a time-dependent increase of caspase-3 and caspase-8 and a decrease of caspase-1 activities in lungs compared to the control group. A marked mitochondrial dysfunction evidenced by cytochrome c (Cyt c) release was also observed as a consequence of PQ exposure. In addition, fluorescence electrophoretic mobility shift assay (fEMSA) revealed a transcriptional induction of the p53 and AP-1 transcription factors in a time-dependent manner as a consequence of PQ exposure. NaSAL treatment resulted in the remission of the observed apoptotic signaling and consequently of lung apoptosis. Taken together, the present results showed that PQ activates several events involved in the apoptotic pathways, which might contribute to its lung toxicodynamics. NaSAL, a recently implemented antidote for PQ intoxications, proved to protect lungs from PQ-induced apoptosis.
 ...
PMID:Sodium salicylate prevents paraquat-induced apoptosis in the rat lung. 1756 Oct 93

Butyrate, a short chain fatty acid, exhibits a wide variety of biological effects including the inhibition of cell growth, change of cellular morphology and the induction of apoptosis. Sodium butyrate-induced apoptosis has been reported to associate with the up-regulation of pro-apoptotic Bax expression, and the down-regulation of anti-apoptotic Bcl-2 and Bcl-XL expressions. However, in some cases, butyrate has also been shown to cause apoptosis without change in Bcl-2, Bcl-XL and/or Bax. This study investigates the detailed mechanisms of sodium butyrate-induced apoptosis. The effect of sodium butyrate was analyzed in the induction of caspase activities, formation of caspase active forms and mRNA levels in human breast cancer cell line MRK-nu-1. Induction of activities of caspase-3, -10 and, to some extent, -8 and formation of DNA fragmentation were observed with sodium butyrate in a dose- and/or time-dependent manner. The levels of caspase-10 mRNA expression markedly increased in a time-dependent manner by the treatment of sodium butyrate, whereas caspase-8 mRNA expression was not changed. Inhibitors of caspase-8 and caspase-10 reduced caspase-3 activity and subsequent DNA fragmentation induced by sodium butyrate. These caspase inhibitors also inhibited the cleavage of pro-caspase-3 to the active forms indicated by Western blotting analysis. Pyrrolidine dithiocarbamate also inhibited the induction of caspase-10 mRNA expression and caspase-3 activation. Contrary to other reports, levels of Bcl-2, Bcl-XL and Bax mRNA expressions were not distinctly changed by even 5 mM sodium butyrate treatment. Our results suggest that sodium butyrate may trigger apoptosis via the induction of the caspase-10 expression.
 ...
PMID:The important role of caspase-10 in sodium butyrate-induced apoptosis. 1820 3

Although many human melanomas express the death receptors TRAIL-R2/DR5 or TRAIL-R1/DR4 on cell surface, they often exhibit resistance to exogenous TRAIL. One of the main contributors to TRAIL-resistance of melanoma cells is upregulation of transcription factors STAT3 and NF-kappaB that control the expression of antiapoptotic genes, including cFLIP and Bcl-xL. On the other hand, the JNK-cJun pathway is involved in the negative regulation of cFLIP (a caspase-8 inhibitor) expression. Our observations indicated that resveratrol, a polyphenolic phytoalexin, decreased STAT3 and NF-kappaB activation, while activating JNK-cJun that finally suppressed expression of cFLIP and Bcl-xL proteins and increased sensitivity to exogenous TRAIL in DR5-positive melanomas. Interestingly, resveratrol did not increase surface expression of DR5 in human melanomas, while gamma-irradiation or sodium arsenite treatment substantially upregulated DR5 expression. Hence, an initial increase in DR5 surface expression (either by gamma-irradiation or arsenite), and subsequent downregulation of antiapoptotic cFLIP and Bcl-xL (by resveratrol), appear to constitute an efficient approach to reactivate apoptotic death pathways in TRAIL-resistant human melanomas. In spite of partial suppression of mitochondrial function and the mitochondrial death pathway, melanoma cells still retain the potential to undergo the DR5-mediated, caspase-8-dependent death pathway that could be accelerated by either an increase in DR5 surface expression or suppression of cFLIP. Taken together, these results suggest that resveratrol, in combination with TRAIL, may have a significant efficacy in the treatment of human melanomas.
 ...
PMID:Resveratrol sensitizes melanomas to TRAIL through modulation of antiapoptotic gene expression. 1822 23

The cytotoxic activity of sodium 5,6-benzylidene-L-ascorbate (SBA) against eight human cancer cell lines and three human normal cells was investigated, SBA showed slightly higher cytotoxicity against human tumor cell lines, as compared with normal cells, with a tumor-specificity index of 2.0. The human myelogenous leukemia cell lines (HL-60, ML-1, KG-1) were the most sensitive to SBA, followed by human oral squamous cell carcinoma (HSC-2, HSC-3, HSC-4) and human glioblastoma (T98G, U87MG). Human oral normal cells (gingival fibroblast, pulp cell, periodontal ligament fibroblast) were the most resistant. In contrast to actinomycin D, SBA induced little or no activation of caspase-3, caspase-8 and caspase-9 in the HSC-2, HSC-4, T98G and HL-60 cells, regardless of incubation time (either 6 or 24 h). SBA induced little or no internucleosomal DNA fragmentation after 6 h in all of these cells. However, prolonged treatment with SBA (24 h) induced a smear pattern of DNA fragmentation in the HSC-2, HSC-4 and T98G cells and a low level of internucleosomal DNA fragmentation in the HL-60 cells. Electron microscopy demonstrated the destruction of mitochondrial structure and autophagocytosis of broken organelles by SBA in the HSC-2, HSC-4 and HL-60 cells. At higher concentrations of SBA, necrotic cell death was observed in the HSC-2 cells, but not in the T98G cells, where the production of acidic organelles (detected by acridine orange staining) was much lower than that attained by nutritional starvation, a well-defined method of inducing autophagy. The present study suggests that SBA induces various degrees of autophagic cell death, followed by either necrosis or apoptosis at laters stage, depending on the cell type.
 ...
PMID:Tumor-specific cytotoxicity and type of cell death induced by sodium 5,6-benzylidene-L-ascorbate. 1903 81

Conventional therapies for the treatment of inflammatory bowel disease (IBD) have demonstrated limited efficacy and potential toxicity; therefore, there is a need for novel therapies that can safely and effectively treat IBD. Recent evidence has indicated that amino acids may play a role in maintaining gut health. L-tryptophan has been shown to reduce oxidative stress and improve neurological states. The objective of this study was to assess the therapeutic effects of L-tryptophan in a porcine model of dextran sodium sulfate (DSS)-induced colitis. DSS was administered to piglets via intragastric catheter for 5 days followed by tryptophan administration at 80% of the daily recommended intake. The severity of colitis was assessed macroscopically and histopathologically, and intestinal permeability was monitored in vivo by D-mannitol analysis. The effect of tryptophan on the local expression of key mediators of inflammation and IBD pathogenesis was examined at the protein and gene expression levels. Supplementation with tryptophan ameliorated clinical symptoms and improved weight gain to feed intake conversion ratios. Histological scores and measurements were also improved, and gut permeability was notably reduced in tryptophan-supplemented animals. Moreover, tryptophan reduced the expression of the pro-inflammatory cytokines tumor necrosis factor-alpha, interleukin (IL)-6, interferon (IFN)-gamma, IL-12p40, IL-1beta and IL-17, as well as IL-8 and intracellular adhesion molecule-1, and resulted in increased expression of apoptosis initiators caspase-8 and Bax. These results demonstrate that L-tryptophan supplementation can reduce inflammation and enhance the rate of recovery in DSS-induced colitis and may be an effective immunomodulating agent for the treatment of IBD.
 ...
PMID:l-Tryptophan exhibits therapeutic function in a porcine model of dextran sodium sulfate (DSS)-induced colitis. 1942 34


<< Previous 1 2 3 4 5 6 7 Next >>