benzyloxycarbonylvalyl-alanyl-aspartyl-fluoromethyl-ketone and Lymphoproliferative-Disorders

Polyamines are involved in the regulation of cellular growth and survival by interacting with processes like translation, transcription or ion transport. The aim of our study was to analyze whether polyamines induce apoptosis in hematopoetic cells and to investigate the molecular mechanisms involved. We found an induction of apoptosis by spermine in primary human cells and malignant tumor cell lines. Spermine-treatment resulted in an intracellular increase of reactive oxygen species. Apoptosis was mediated by a collapse of mitochondrial membrane potential, a decrease in Bcl-2 expression and a release of apoptosis mediating molecules from mitochondrial intermembrane space (cytochrome C, Smac/DIABLO). Spermine-mediated apoptosis was caspase-dependent. To test whether spermine mediates apoptosis through metabolites we analyzed the effects of several molecules that interfere with its catabolism. Aminoguanidine, an inhibitor of serum amine oxidase, aldehyde-dehydrogenase, which degrades aldehydes to less reactive molecules or N-acetyl-cysteine, a glutathion precursor, significantly inhibited spermine-mediated apoptosis. From these data we conclude that spermine-derived aldehydes and intracellular accumulation of reactive oxygen species result in mitochondria mediated apoptosis.

Topics: Acetylcysteine; Amine Oxidase (Copper-Containing); Amino Acid Chloromethyl Ketones; Apoptosis; Apoptosis Regulatory Proteins; Caspase Inhibitors; Cell Line, Tumor; Cytochromes c; Dexamethasone; fas Receptor; Humans; Hydrogen Peroxide; Intracellular Signaling Peptides and Proteins; Leukocytes, Mononuclear; Lymphoproliferative Disorders; Membrane Potentials; Mitochondria; Mitochondrial Proteins; Polyamines; Proto-Oncogene Proteins c-bcl-2; Putrescine; Reactive Oxygen Species; Spermidine; Spermine

Epstein-Barr virus (EBV) transforms B lymphocytes into lymphoblastoid cell lines usurping the Notch and tumor necrosis factor receptor pathways to effect transcription including NF-kappaB activation. To determine whether NF-kappaB activity is essential in the growth and survival of EBV-transformed lymphoblastoid cell lines, a nondegradable IkappaBalpha mutant was expressed under tetracycline regulation. Despite continued Bcl-2 and Bcl-x/L expression, NF-kappaB inhibition induced apoptosis as evidenced by poly(ADP-ribose) polymerase cleavage, nuclear condensation and fragmentation, and hypodiploid DNA content. Both caspase 3 and 8 activation and loss of mitochondrial membrane potential were observed in apoptotic cells. However, caspase inhibition failed to block apoptosis. These experiments indicate that NF-kappaB inhibitors may be useful in the therapy of EBV-induced cellular proliferation.

Topics: Amino Acid Chloromethyl Ketones; Apoptosis; B-Lymphocytes; Caspase 3; Caspase 8; Caspase 9; Caspase Inhibitors; Caspases; Cell Cycle; Cell Line, Transformed; Cell Transformation, Viral; Cysteine Proteinase Inhibitors; DNA-Binding Proteins; Drug Design; Flow Cytometry; Gene Expression Regulation; Herpesvirus 4, Human; Humans; I-kappa B Proteins; Intracellular Membranes; Lymphoproliferative Disorders; Membrane Potentials; Microscopy, Confocal; Minor Histocompatibility Antigens; Mitochondria; NF-kappa B; NF-KappaB Inhibitor alpha; Protein Biosynthesis; Proteins; Proto-Oncogene Proteins c-bcl-2; Recombinant Fusion Proteins; Transfection