benzyloxycarbonylvalyl-alanyl-aspartyl-fluoromethyl-ketone and Acute-Disease

Topics: Acute Disease; Amino Acid Chloromethyl Ketones; Antineoplastic Agents; Apoptosis; Benzamides; Caspases; Cell Death; Cell Line, Tumor; Diphtheria Toxin; Drug Delivery Systems; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; Drug Synergism; Enzyme Activation; Humans; Interleukin-3; Leukemia, Myeloid; Neoplasm Proteins; Pyridines; Receptors, Granulocyte-Macrophage Colony-Stimulating Factor; Receptors, Interleukin-3; Recombinant Fusion Proteins; TNF-Related Apoptosis-Inducing Ligand; U937 Cells

The mechanisms of As(2)O(3)-induced apoptosis are very complex. In the present study, we investigated the molecular mechanism of As(2)O(3) in vitro at low concentration (0.25-2.0 micro M) on three human leukemia/lymphoma cell lines: HL-60, RL and K562. As(2)O(3) inhibited the growth of these cell lines significantly. During As(2)O(3) treatment, two forms of cell death, apoptosis in HL-60 and RL and oncosis in K562, were found by morphological study. In HL-60 and RL, cell cycle analysis showed, at a distinct SubG1 region, that CD95 and CD95 ligand (CD95L) expression was upregulated, caspase 8 and caspase 3 were activated, and Bcl-2 protein expression was downregulated. On the other hand, in K562, the cell cycle was arrested at the G2+M phase, CD95/CD95L expression was upregulated, caspase 8 and caspase 3 were activated, but Bcl-2 expression was not changed as compared with untreated cells. These findings suggest that the CD95/CD95L pathway is involved in cell killing by As(2)O(3). Using anti-CD95 IgG monoclonal antibody (anti-CD95 MoAb) or specific caspase inhibitor ZVAD-fmk to block the CD95 pathway, the cell death induced by As(2)O(3) was partially blocked in each cell line. These results suggest that As(2)O(3) inhibits the growth of these leukemia/lymphoma cell lines by inducing apoptosis or oncosis that is partially mediated by the CD95/CD95L pathway.

Topics: Acute Disease; Amino Acid Chloromethyl Ketones; Antibodies, Monoclonal; Antineoplastic Agents; Apoptosis; Arsenic Trioxide; Arsenicals; Caspase 3; Caspase 8; Caspase 9; Caspases; Cell Division; Cysteine Proteinase Inhibitors; Down-Regulation; Fas Ligand Protein; fas Receptor; HL-60 Cells; Humans; K562 Cells; Leukemia, Myeloid; Membrane Glycoproteins; Oxides; Proto-Oncogene Proteins c-bcl-2; Tumor Cells, Cultured; Up-Regulation

Topics: Acute Disease; Amino Acid Chloromethyl Ketones; Animals; Apoptosis; Cartilage, Articular; Caspase Inhibitors; Chondrocytes; Cysteine Proteinase Inhibitors; Hindlimb; In Situ Nick-End Labeling; Injections, Intra-Articular; Leg Injuries; Rabbits

LPS (lipopolysaccharide) is one of the major factors that induce acute lung injury. Recently, it was reported that LPS induced disseminated endothelial apoptosis, preceding nonendothelial tissue damage. Caspases play important roles in apoptosis, including tumor necrosis factor-alpha-induced apoptosis, in several systems. We therefore investigated whether the injection of a caspase inhibitor prevents LPS-induced apoptosis and acute lung injury in mice. LPS (30 mg/kg) was administered intravenously to Institute for Cancer Research mice. Electron microscopic findings demonstrated characteristic features of apoptosis in endothelial cells and alveolar epithelial cells. The caspase-3 activity and the number of terminal dUTP nick-end labeling-positive cells in lung tissues were significantly increased after LPS administration. Benzyloxycarbonil-Val-Ala-Asp fluoromethylketone (Z-VAD.fmk), which is a broad-spectrum caspase inhibitor, was injected before and after the administration of LPS. The injection of Z-VAD.fmk suppressed the caspase-3 activity in lung tissues, and significantly decreased the number of terminal dUTP nick-end labeling-positive cells. Furthermore, the survival rate of mice was prolonged significantly by the injection of Z-VAD.fmk. These results indicate that apoptosis may play an important role in acute lung injury, and thus that inhibition of caspase activity may constitute a new therapeutic approach for treatment of this disease.

Topics: Acute Disease; Amino Acid Chloromethyl Ketones; Animals; Apoptosis; Caspase 1; Caspase 3; Caspase Inhibitors; Caspases; Cysteine Proteinase Inhibitors; Interleukin-1; Lipopolysaccharides; Lung; Lung Diseases; Mice; Mice, Inbred ICR; Survival Analysis

P39/Tsugane is a myelomonocytoid cell line derived from a patient with myelodysplastic syndrome (MDS). The cells readily undergo apoptosis in response to various agents, and the cell line has been suggested as a useful model to study apoptosis in MDS. The aims of the present study were to assess differentiation and apoptosis induced with all-trans retinoic acid (ATRA) and etoposide, to characterize the mode of apoptosis in these two model systems, and to assess the influence of granulocyte colony-stimulating factor (G-CSF), which in combination with erythropoietin has been shown to inhibit apoptosis in MDS. ATRA induced differentiation and apoptosis in a concentration- and time-dependent manner. Differentiated cells were partially rescued (by 50%) from apoptosis with G-CSF. Etoposide induced apoptosis in a concentration- and time-dependent manner, but no signs of preceding maturation or G-CSF rescue were detected. ATRA- and etoposide-induced apoptosis were both mediated through the caspase pathway and were partially blocked with the general caspase inhibitor zVAD-fmk. Simultaneous treatment with G-CSF and zVAD-fmk additively blocked ATRA-induced apoptosis. However, the two pathways differed in terms of substrate cleavage during apoptosis. ATRA-induced apoptosis caused actin cleavage, which was not affected by G-CSF, and Bcl-2 downregulation. Etoposide induced a caspase-dependent cleavage of Bcl-2, while actin remained intact. The Fas system did not seem to play a major role in any of these apoptotic pathways. Our results may provide new tools to study the mechanisms of apoptosis in MDS.

Topics: Actins; Acute Disease; Amino Acid Chloromethyl Ketones; Antibodies, Monoclonal; Apoptosis; Blast Crisis; Caspase Inhibitors; Caspases; Cell Differentiation; Cysteine Proteinase Inhibitors; Cytoskeleton; Erythropoietin; Etoposide; fas Receptor; Granulocyte Colony-Stimulating Factor; Humans; Leukemia, Myeloid; Myelodysplastic Syndromes; Neoplasm Proteins; Proto-Oncogene Proteins c-bcl-2; Signal Transduction; Tretinoin; Tumor Cells, Cultured