Search results for "FAS"
showing 10 items of 2015 documents
Cleavage of CD95 by matrix metalloproteinase-7 induces apoptosis resistance in tumour cells
2004
The ability of tumour cells to resist apoptosis-inducing signals by cytotoxic T cells may decide the success or failure of tumour elimination. An important effector of apoptosis is the CD95/CD95 ligand system (APO-1/Fas) that mediates perforin-independent cytotoxic T-cell killing of tumour cells. We propose a new strategy by which tumour cells can resist CD95-induced apoptosis. We identified matrix metalloproteinase-7, MMP-7 (Martilysin), as the first physiologically relevant protease that can specifically cleave CD95. MMP-7 is of unique importance because it is produced by the tumour cells themselves at early stages of tumour development. Microsequencing of the positions in CD95 cleaved by…
Apoptotic effects of thiazolobenzimidazole derivatives on sensitive and multidrug resistant leukaemic cells
2001
We investigated the cytotoxic activity of eight thiazolobenzimidazole derivatives on sensitive HL60 and multidrug-resistant (MDR) (HL60R) leukaemia cell lines. The antitumour effects of these compounds were compared with those of RS-TBZ, a thiazolobenzimidazole derivative, previously described in our reports, that was able to induce apoptosis more markedly in MDR cells than in the parental sensitive cell lines. Only two compounds in this study proved to have interesting effects: (a) the S-enantiomer of TBZ, that was able to induce apoptosis in MDR cells in a slightly more selective manner than TBZ (racemic form); and (b) TBZ-4-OCH3 (TBZ-4-OCH3), that showed cytotoxic and apoptotic effects o…
Redistribution of CD95, DR4 and DR5 in rafts accounts for the synergistic toxicity of resveratrol and death receptor ligands in colon carcinoma cells.
2004
The natural phytoalexin resveratrol (3, 5, 4'-trihydroxystilbene) exhibits both chemopreventive and antitumor activities through a variety of mechanisms. We have shown previously that resveratrol-induced apoptosis of a human colon cancer cell line involved the redistribution of CD95 (Fas/Apo-1) into lipid rafts. Here, we show that, in colon cancer cells that resist to resveratrol-induced apoptosis, the polyphenol also induces a redistribution of death receptors into lipid rafts. This effect sensitizes these tumor cells to death receptor-mediated apoptosis. In resveratrol-treated cells, tumor necrosis factor (TNF), anti-CD95 antibodies and TNF-related apoptosis-inducing ligand (TRAIL) activa…
Fascin upregulation in primary head and neck squamous cell carcinoma is associated with lymphatic metastasis
2014
Fascin is an actin-bundling protein that is associated with cellular motility and cancer-cell invasion. The present study aimed to examine the expression of fascin in head and neck squamous cell carcinoma (HNSCC) and its potential use as a biomarker. In a prospective study with a median follow-up time of 48.8 months, tumor tissues, adjacent healthy tissues and cervical lymph node metastases were collected from 25 patients and analyzed by immunohistochemistry. The specimens were scored according to the intensity of fascin staining and the percentage of tumor cells stained using a semi-quantitative scoring approach; the data were analyzed and correlated with clinical follow-up observations. A…
Spontaneous and Fas-induced apoptosis of low-grade MDS erythroid precursors involves the endoplasmic reticulum
2008
Spontaneous apoptosis of bone marrow erythroid precursors accounts for the anemia that characterizes most low-grade myelodysplastic syndromes (MDS). We have shown that death of these precursors involved the Fas-dependent activation of caspase-8. To explore the pathway leading from caspase-8 activation to apoptosis, we transduced MDS bone marrow CD34(+) cells with a lentivirus encoding wild-type (WT) or endoplasmic reticulum (ER)-targeted Bcl-2 protein before inducing their erythroid differentiation. Both WT-Bcl-2 and ER-targeted Bcl-2 prevented spontaneous and Fas-dependent apoptosis in MDS erythroid precursors. ER-targeted Bcl-2 inhibited mitochondrial membrane depolarization and cytochrom…
Chemotherapy-induced apoptosis in hepatocellular carcinoma involves the p53 family and is mediatedviathe extrinsic and the intrinsic pathway
2010
We investigated the downstream mechanisms by which chemotherapeutic drugs elicit apoptosis in hepatocellular carcinoma (HCC). Genomic signatures of HCC cell lines treated with different chemotherapeutic drugs were obtained. Analyses of apoptosis pathways were performed and RNA interference was used to evaluate the role of the p53 family. Endogenous p53, p63 and p73 were upregulated in response to DNA damage by chemotherapeutic drugs. Blocking p53 family function led to chemoresistance in HCC. Stimulation and blocking experiments of the CD95-, the TNF- and the TRAIL-receptor systems revealed that cytotoxic drugs, via the p53 family members as transactivators, can trigger expression of each o…
Histone deacetylase inhibition by valproic acid down-regulates c-FLIP/CASH and sensitizes hepatoma cells towards CD95-and TRAIL receptor-mediated apo…
2005
Hepatocellular carcinoma (HCC) is highly resistant to chemotherapy, leading to a poor prognosis of advanced disease. Inhibitors of histone deacetylase (HDACi) induce re-differentiation in tumor cells and thereby re-establish sensitivity towards apoptotic stimuli. HDACi are entering the clinical stage of tumor treatment, and several substances are currently being tested in clinical trials to prove their efficacy in the treatment of leukemias and solid tumors. In this study, we investigated the impact of the HDACi valproic acid (VA) on TRAIL- and CD95-mediated apoptosis in hepatoma cells, as well as its sensitizing effect on a chemotherapeutic agent. Treatment of HepG2 cells with VA increased…
Apoptosis and the liver
2000
Regulation of the homeostatic balance between cell proliferation and programmed cell death, apoptosis, is essential for development and maintenance of multicellular organisms. Apoptosis is a genetically and evolutionarily highly conserved process. Analysis of the molecular mechanisms of apoptosis has led to a better understanding of many human diseases. Notably in cancer, but also in infectious or autoimmune disease, a deficiency in apoptosis is one of the key events in pathophysiology. On the other hand, overefficient apoptosis, as observed in fulminant liver failure, may be equally harmful for the organism indicating that a tight regulation of the apoptotic machinery is essential for surv…
Targeting apoptosis proteins in hematological malignancies
2010
The apoptotic machinery plays a key role in hematopoietic cell homeostasis. Terminally differentiated cells are eliminated, at least in part, by apoptosis, whereas part of the apoptotic machinery, including one or several caspases, is required to go through very specific steps of the differentiation pathways. A number of hematological diseases involve a deregulation of this machinery, which in most cases is a decrease in cell sensitivity to pro-apoptotic signals through over-expression of anti-apoptotic molecules. In some situations however, e.g. in the erythroid lineage of low grade myelodysplastic syndromes, cell sensitivity to apoptosis is increased in a death receptor-dependent manner a…
JNK and AP-1 mediate apoptosis induced by bortezomib in HepG2 cells via FasL/caspase-8 and mitochondria-dependent pathways
2006
The proteasome inhibitor bortezomib is an efficacious apoptotic agent in many tumor cells. This paper shows that bortezomib induced apoptosis in human hepatoma HepG2 cells associated with many modifications in the expression of survival or death factors. Although bortezomib increased the level of the protective factors HSP70 and HSP27, the effects of the drug that favour cell death were predominant. These events include accumulation of c-Jun, phospho-c-Jun and p53; increase in FasL level with activation of caspase-8; changes related to members of Bcl-2 family with increase in the level of pro-apoptotic members and decrease in that of anti-apoptotic ones; dissipation of mitochondrial potenti…