Defective Apoptotic Signal Transduction Pathway Downstream of Caspase-3 in Human B-Lymphoma Cells: A Novel Mechanism of Nuclear Apoptosis Resistance

• Published in: Blood Vol. 94; no. 10; pp. 3523 - 3530
• Main Authors: Kawabata, Yoshinari, Hirokawa, Makoto, Kitabayashi, Atsushi, Horiuchi, Takahiro, Kuroki, Jun, Miura, Akira B.
• Format: Journal Article
• Language: English
• Published: Washington, DC Elsevier Inc 15.11.1999; The Americain Society of Hematology
• Subjects: Alkylating Agents - pharmacology; Apoptosis; Biological and medical sciences; Caspase 3; Caspases - metabolism; Ceramides - pharmacology; Cytosol - metabolism; DNA - metabolism; DNA Fragmentation; Enzyme Activation; Hematologic and hematopoietic diseases; HL-60 Cells; Humans; K562 Cells; Leukemias. Malignant lymphomas. Malignant reticulosis. Myelofibrosis; Lymphoma, B-Cell - enzymology; Lymphoma, B-Cell - metabolism; Lymphoma, B-Cell - pathology; Medical sciences; Membrane Potentials - drug effects; Mitochondria - drug effects; Mitochondria - physiology; Protein Biosynthesis; Proteins; Signal Transduction; tert-Butylhydroperoxide - pharmacology; U937 Cells; Human; Enzyme; Cysteine endopeptidases; Cell nucleus; Burkitt lymphoma; Malignant hemopathy; B-Lymphocyte; Non Hodgkin lymphoma; Infection; Resistance; Peptidases; Signal transduction; Interleukin 1-β converting enzyme; Cell death; Lymphoproliferative syndrome; Viral disease; Established cell line; Hydrolases; Apoptosis
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V94.10.3523.422k07_3523_3530

Mitochondria play a central role in controlling apoptosis, and activation of the caspase cascade appears to be crucial event during the apoptotic process. Human B lymphoma Raji cells are resistant to nuclear apoptosis induced by various stimuli. Using this cell line, we have asked whether reduction of the mitochondrial transmembrane potential and activation of caspase-3 are sufficient to induce DNA fragmentation during the apoptotic process. After stimulation with cell-permeable C2-ceramide or mitochondrial permeability transition (PT) inducers, not only apoptosis-sensitive cell lines (HL-60, Jurkat, and Daudi cells), but also Raji cells showed reduction of the mitochondrial transmembrane potential (▵ψm), activation of caspase-3, and loss of clonogenic potential. However, Raji cells did not show detectable levels of nuclear apoptosis (DNA degradation). In a cell-free system, cell lysates from tetra-butylhydroperoxide (t-BHP)–treated HL-60 cells induced DNA degradation of Raji nuclei, whereas cell lysates from t-BHP–treated Raji cells failed to induce DNA degradation in either apoptosis-sensitive cell lines or apoptosis-resistant Raji cells. Cleavage of DFF-45, which is a downstream target molecule for caspase-3, was observed in Raji cells as well as in apoptosis-sensitive Daudi cells. These results indicate that there is a defective apoptotic pathway in the cytoplasm downstream of caspase-3 in Raji cells.