Activation of caspase‐3 alone is insufficient for apoptotic morphological changes in human neuroblastoma cells

• Published in: Journal of neurochemistry Vol. 80; no. 6; pp. 1039 - 1048
• Main Authors: Racke, Margaret M., Mosior, Marian, Kovacevic, Steve, Chang, Chan Hsin S., Glasebrook, Andrew L., Roehm, Neal W., Na, Songqing
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science, Ltd 01.03.2002; Blackwell
• Subjects: Ageing, cell death; Anti-Bacterial Agents - pharmacology; apoptosis; Apoptosis - drug effects; Apoptosis - physiology; apoptotic morphology; Biological and medical sciences; Blotting, Western; Caspase 3; caspase activity; Caspases - genetics; Caspases - metabolism; Cell physiology; Cell Survival - drug effects; Doxycycline - pharmacology; Enzyme Activation - drug effects; Enzyme Activation - physiology; Enzyme Inhibitors - pharmacology; Fundamental and applied biological sciences. Psychology; Gene Expression; Humans; Molecular and cellular biology; Neuroblastoma - metabolism; Neuroblastoma - pathology; Protein Structure, Tertiary - physiology; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; regulated expression; Staurosporine - pharmacology; Transfection; Tumor Cells, Cultured; Human; Enzyme; Caspase; Neuroblastoma; Gene expression; Caspase-3; Peptidases; Cell line; Neuron; Enzymatic activity; Cell death; Morphology; Hydrolases; Fusion protein; Apoptosis
• DOI: 10.1046/j.0022-3042.2002.00787.x
• ISSN: 0022-3042

Activated caspase‐3 is considered an important enzyme in the cell death pathway. To study the specific role of caspase‐3 activation in neuronal cells, we generated a stable tetracycline‐regulated SK‐N‐MC neuroblastoma cell line, which expressed a highly efficient self‐activating chimeric␣caspase‐3, consisting of the caspase‐1 prodomain fused to the caspase‐3 catalytic domain. Under expression‐inducing conditions, we observed a time‐dependent increase of processed caspase‐3 by immunostaining for the active form of the enzyme, intracellular caspase‐3 enzyme activity, as well as poly(ADP‐ribose) polymerase (PARP) cleavage. Induced expression of the caspase fusion protein showed predominantly caspase‐3 activity without any apoptotic morphological changes. In contrast, staurosporine treatment of the same cells resulted in activation of multiple caspases and profound apoptotic morphology. Our work provides evidence that auto‐activation of caspase‐3 can be efficiently achieved with a longer prodomain and that neuronal cell apoptosis may require another caspase or activation of multiple caspase enzymes.