15-hydroperoxy-5-8-11-13-eicosatetraenoic-acid and Precursor-Cell-Lymphoblastic-Leukemia-Lymphoma

The antiproliferative effects of 15-LOX (15-lipoxygenase) metabolites of arachidonic acid {(15S)-HPETE [(15S)-hydroperoxyeicosatetraenoic acid] and (15S)-HETE [(15S)-hydroxyeicosatetraenoic acid]} and the mechanism(s) involved were studied in the human T-cell leukaemia cell line Jurkat. (15S)-HPETE, the hydroperoxy metabolite of 15-LOX, inhibited the growth of Jurkat cells 3 h after exposure and with an IC(50) value of 10 microM. The hydroxy metabolite of 15-LOX, (15S)-HETE, on the other hand, inhibited the growth of Jurkat cells after 6 h of exposure and with an IC(50) value of 40 microM. The cells exposed to 10 microM (15S)-HPETE for 3 h or to 40 microM (15S)-HETE for 6 h showed increased expression of Fas ligand and FADD (Fas-associated death domain), caspase 8 activation, Bid (BH3-interacting domain death agonist) cleavage, decrease in mitochondrial membrane potential, cytochrome c release, caspase 3 activation, PARP-1 [poly(ADP-ribose) polymerase-1] cleavage and DNA fragmentation, suggesting the involvement of both extrinsic and intrinsic death pathways. Further studies on ROS (reactive oxygen species) generation revealed the involvement of NADPH oxidase. In conclusion, the present study indicates that NADPH oxidase-induced ROS generation activates the Fas-mediated death pathway.

Topics: Animals; Apoptosis; Apoptosis Regulatory Proteins; Arachidonate 15-Lipoxygenase; Caspases; Cell Cycle; Cell Death; Cell Proliferation; Cytochromes c; DNA Fragmentation; Enzyme Activation; Fas Ligand Protein; fas Receptor; Flow Cytometry; Humans; Jurkat Cells; Leukotrienes; Lipid Peroxides; Membrane Potential, Mitochondrial; NADPH Oxidases; Poly(ADP-ribose) Polymerases; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Proto-Oncogene Proteins c-akt; Reactive Oxygen Species; Signal Transduction; Stereoisomerism