Involvement of mitochondrial permeability transition and caspase-9 activation in dimethyl sulfoxide-induced apoptosis of EL-4 lymphoma cells.
We observed that dimethyl sulfoxide (DMSO) induced apoptotic changes in the EL-4 murine lymphoma cell line and that effect was dependent on the concentration and time period. Incubating cells over a period of 18 h, 2.5% DMSO was found to induce sub-G1 peak in DNA histograms analyzed by flowcytometer and nucleosomal ladder formation in DNA gel electrophoresis. We also found down-regulation of Bcl-2, collapse of mitochondrial membrane potential (delta psi m) occurred following DMSO treatment, and release of cytochrome c from the mitochondria to cytosol. These observations suggest that DMSO converted its pro-apoptotic signal at the mitochondria. In the involvement of caspases, caspase-9 and -3, but not caspase-8, were found to be activated responding to DMSO treatment. Inhibitory experiments demonstrated that caspase cascade of mitochondrial apoptotic pathway was indispensable for DMSO-induced apoptosis. In the caspase cascade, caspase-9 was an upstream initiator and its primary signal could be transduced and amplified by caspase-3, -6 and -7. Kinetic study of these data showed mitochondrial dysfunction and caspase activation occurred at 12 h and apoptotic change of nuclear DNA at 18 h, providing another support for the transduction of DMSO pro-apoptotic signal via the mitochondrial pathway.
Liu
J
J
Department of Parasitology and Immunology, Yamanashi Medical University, Yamanashi 409-3898, Japan.
Yoshikawa
H
H
Nakajima
Y
Y
Tasaka
K
K
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism*; D004121:Dimethyl Sulfoxide / Q000494:pharmacology*; D004789:Enzyme Activation; D016399:Lymphoma, T-Cell / Q000201:enzymology / Q000473:pathology; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D008928:Mitochondria / Q000187:drug effects; D010539:Permeability / Q000187:drug effects; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D012997:Solvents / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D019253:Proto-Oncogene Proteins c-bcl-2; D012997:Solvents; C506434:Casp9 protein, mouse; D053453:Caspase 9; D020169:Caspases; D004121:Dimethyl Sulfoxide