Search results for "Caspase Inhibitor"
showing 10 items of 26 documents
Potassium regulates IL-1 beta processing via calcium-independent phospholipase A2.
2000
Abstract We report that potassium leakage from cells leads to activation of the Ca2+-independent phospholipase A2 (iPLA2), and the latter plays a pivotal role in regulating the cleavage of pro-IL-1β by the IL-converting enzyme caspase-1 in human monocytes. K+ efflux led to increases of cellular levels of glycerophosphocholine, an unambiguous indicator of phospholipase A2 activation. Both maturation of IL-1β and formation of glycerophosphocholine were blocked by bromoenol lactone, the specific iPLA2 inhibitor. Bromoenol lactone-dependent inhibition of IL-1β processing was not due to perturbation of the export machinery for pro-IL-1β and IL-1β or to caspase-1 suppression. Conspicuously, activ…
Dinitrosyl-iron triggers apoptosis in Jurkat cells despite overexpression of Bcl-2
2004
Cells expressing the cytokine-inducible NO synthase are known to trigger apoptosis in neighboring cells. Paramagnetic dinitrosyl nonheme iron complexes (DNIC) were found in tumor tissue about 40 years ago; however, the role of these NO(+)-bearing species is not completely understood. In the human Jurkat leukemia cell line, the application of the model complex DNIC-thiosulfate (50-200 microM) induced apoptosis (defined by phosphatidylserine externalization) in a concentration- and time-dependent manner. In Jurkat cells, the pan-caspase inhibitor, zVADfmk (50 microM), and/or stable transfection of antiapoptotic protein, Bcl-2, was unable to afford protection against DNIC-induced apoptosis. Th…
Early mitochondrial dysfunction, superoxide anion production, and DNA degradation are associated with non-apoptotic death of human airway epithelial …
2002
It has been shown that bacterial exoproducts may induce airway epithelium injury. During the epithelial repair process, the respiratory epithelial cells no more establish tight junctional intercellular complexes and may be particularly susceptible to bacterial virulence factors. In this study, we analyzed the effect of Pseudomonas aeruginosa exotoxin A (ETA) at different periods of time and concentrations on 16 HBE 14o(-) human bronchial epithelial cells in culture conditions inducing a phenotype of repairing cells. ETA treatment for 24 and 48 h led to the killing of 40.0 +/- 5.7% and 79.0 +/- 1.4% of the cells, respectively, as determined by the dimethylthiazole 2,5 diphenyl tetrazolium br…
Up-regulation of c-FLIPshort and reduction of activation-induced cell death in T-cells from patients with Type 1 diabetes
2004
AICD of T-cells is an efficient way of removing activated T-lymphocytes. In this study we investigated the molecular basis of AICD upon reactivation in peripheral T-lymphocytes from newly diagnosed T1DM patients and age-matched healthy controls. In an in vitro model system, PHA-stimulated T-cells, upon prolonged culture in IL-2, acquire a sensitive phenotype to Fas-mediated apoptosis. This phenomenon is less pronounced in T1DM T-cells. Moreover, the restimulation of activated T-cells via TCR/CD3 and/or via CD28 inhibits Fas-mediated apoptosis in T1DM in comparison to control T-cells. After Fas triggering, the generation of the active sub-units of caspase-8 is significantly reduced in T1DM T…
Effects of small interfering RNAs targeting fascin on human esophageal squamous cell carcinoma cell lines
2010
Abstract Background Fascin induces membrane protrusions and cell motility. Fascin overexpression was associated with poor prognosis, and its downregulation reduces cell motility and invasiveness in esophageal squamous cell carcinoma (ESCC). Using a stable knockdown cell line, we revealed the effect of fascin on cell growth, cell adhesion and tumor formation. Methods We examined whether fascin is a potential target in ESCC using in vitro and in vivo studies utilizing a specific siRNA. We established a stable transfectant with downregulated fascin from KYSE170 cell line. Results The fascin downregulated cell lines showed a slower growth pattern by 40.3% (p In vivo, the tumor size was signific…
Benfotiamine accelerates the healing of ischaemic diabetic limbs in mice through protein kinase B/Akt-mediated potentiation of angiogenesis and inhib…
2006
Benfotiamine, a vitamin B1 analogue, reportedly prevents diabetic microangiopathy. The aim of this study was to evaluate whether benfotiamine is of benefit in reparative neovascularisation using a type I diabetes model of hindlimb ischaemia. We also investigated the involvement of protein kinase B (PKB)/Akt in the therapeutic effects of benfotiamine. Streptozotocin-induced diabetic mice, given oral benfotiamine or vehicle, were subjected to unilateral limb ischaemia. Reparative neovascularisation was analysed by histology. The expression of Nos3 and Casp3 was evaluated by real-time PCR, and the activation state of PKB/Akt was assessed by western blot analysis and immunohistochemistry. The f…
Caspase-mediated apoptosis in sponges: cloning and function of the phylogenetic oldest apoptotic proteases from Metazoa
2003
AbstractSponges (phylum Porifera) represent the phylogenetically oldest metazoan phylum. These animals have complex cell adhesion and powerful immune systems which allow the formation of a distinct body plan. Consequently, an apoptotic machinery has to be predicted that allows sponges to eliminate unwanted cells accumulating during development. With the marine sponge Geodia cydonium, it is shown that allografts of these animals undergo apoptosis as demonstrated by apoptotic DNA fragmentation. Extracts from allografts contain an enzymic activity characteristic for caspases; as substrate to determine the cleavage activity, Ac-DEVD-AMC was applied. cDNAs encoding predicted caspase-3-related pr…
Small molecule inhibitors of Apaf-1-related caspase- 3/-9 activation that control mitochondrial-dependent apoptosis
2006
10 pages, 5 figures.-- PMID: 16341125 [PubMed].-- Available online Dec 9, 2005.
Caspase-dependent apoptosis during infection with Cryptosporidium parvum
1999
The protozoan parasite Cryptosporidium parvum causes persistent diarrhea and malnutrition in children and the diarrhea-wasting syndrome in AIDS. No therapy exists for eliminating the parasite in the absence of a healthy immune response. Although it had been reported that infection of intestinal cell lines with C. parvum leads to host cell death, the mechanisms of cytolysis have not been characterized. We show here that infection with C. parvum leads to typical apoptotic nuclear condensation and DNA fragmentation in host cells. Both nuclear condensation and DNA fragmentation are inhibited by a caspase inhibitor, showing that caspases are involved in this type of apoptosis. Finally, blocking …
Parthenolide induces caspase-independent and AIF-mediated cell death in human osteosarcoma and melanoma cells
2013
The mechanism of the cytotoxic effect exerted by parthenolide on tumor cells is not clearly defined today. This article shows that parthenolide stimulates in human osteosarcoma MG63 and melanoma SK-MEL-28 cells a mechanism of cell death, which is not prevented by z-VAD-fmk and other caspase inhibitors. In particular treatment with parthenolide rapidly stimulated (1-2 h) reactive oxygen species (ROS) generation by inducing activation of extracellular signal-regulated kinase 1/2 (ERK 1/2) and NADPH oxidase. This event caused depletion of thiol groups and glutathione, NF-κB inhibition, c-Jun N-terminal kinase (JNK) activation, cell detachment from the matrix, and cellular shrinkage. The increa…