[The role of mitochondria in apoptosis in U937 and Molt-4 cells: difference in order of mitochondrial membrane potential (delta psi m) reduction and interleukin-1 beta-converting enzyme (ICE) on signal transduction pathway in each cell type].
Time-course-analysis of two apoptotic events of DNA fragmentation and delta psi m reduction revealed that delta psi m reduction preceded DNA fragmentation in U937 and Molt-4 cells treated with etoposide (ETP). DNA fragmentation and delta psi m reduction were inhibited by N-acetylcysteine (NAC) in both cell lines treated with ETP. These findings suggest that DNA fragmentation was inhibited through maintenance of delta psi m. Z-Asp-CH2-DCB, interleukin-1 beta-converting enzyme (ICE) specific inhibitor, inhibited ETP-induced DNA fragmentation and delta psi m reduction in U937 cells. This suggests that activation of ICE is an earlier event than delta psi m reduction. On the other hand, in Molt-4 cells, Z-Asp-CH2-DCB inhibited ETP-induced DNA fragmentation but not delta psi m reduction, suggesting that delta psi m reduction occurs earlier than activation of ICE.
Kawaguchi
M
M
Dept. of Pediatrics, Aichi Medical University.
Nakamura
A
A
Tsurusawa
M
M
D017209:Apoptosis; D020170:Caspase 1 / Q000502:physiology*; D053938:DNA Fragmentation; D005047:Etoposide / Q000494:pharmacology; D006801:Humans; D007951:Leukemia, Myeloid / Q000473:pathology; D015458:Leukemia, T-Cell / Q000473:pathology; D008564:Membrane Potentials; D008928:Mitochondria / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D014407:Tumor Cells, Cultured; D020298:U937 Cells
D005047:Etoposide; D020170:Caspase 1