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Induction of apoptotic cell death in a neuroblastoma cell line by dibucaine
1Department of Neurological Surgery, Loyola University Medical Center, Maywood, Illinois 60153, USA.
Abstract:
Dibucaine, a local anesthetic known to interact with cell membranes, induced apoptosis in SK-N-MC human neuroblastoma cells in a dose-dependent manner. Apoptosis was demonstrated by direct visualization of morphological nuclear changes using a DAPI staining technique and confirmed by the production of characteristic ladder patterns of DNA fragmentation on gel electrophoresis. At concentrations which induced apoptosis, dibucaine significantly altered membrane fluidity, indicating that fluidity may be a major target for the cytotoxic action of dibucaine. Also, dibucaine increased intracellular calcium levels more effectively in calcium-containing Krebs-Ringer buffer than in calcium-free Krebs-Ringer buffer. Removal of extracellular calcium or addition of antioxidants or protein synthesis inhibitor effectively blocked dibucaine-induced apoptosis. These results suggest that membrane damage, intracellular calcium levels, and oxygen free radicals may be involved in the apoptosis induced by dibucaine.
Insights
Dibucaine, a local anesthetic, triggers programmed cell death (apoptosis) in human neuroblastoma cells by altering cell membrane fluidity. This process involves calcium influx and free radicals, but can be blocked by removing extracellular calcium.
Area of Science:
- Neuroscience
- Cell Biology
- Pharmacology
Background:
- Dibucaine is a local anesthetic known to interact with cell membranes.
- Neuroblastoma is a type of cancer that forms in certain types of nerve tissue.
Purpose of the Study:
- To investigate the mechanism by which dibucaine induces apoptosis in SK-N-MC human neuroblastoma cells.
- To explore the role of cell membrane fluidity, intracellular calcium, and oxygen free radicals in dibucaine-induced apoptosis.
Main Methods:
- Cells were treated with varying concentrations of dibucaine.
- Apoptosis was assessed using DAPI staining for nuclear morphology and gel electrophoresis for DNA fragmentation.
- Membrane fluidity was measured.
- Intracellular calcium levels were monitored.
- The effects of extracellular calcium removal, antioxidants, and protein synthesis inhibitors were evaluated.
Main Results:
- Dibucaine induced apoptosis in a dose-dependent manner.
- Dibucaine significantly altered membrane fluidity at cytotoxic concentrations.
- Dibucaine increased intracellular calcium levels, particularly in the presence of extracellular calcium.
- Apoptosis was blocked by removing extracellular calcium, adding antioxidants, or adding a protein synthesis inhibitor.
Conclusions:
- Dibucaine-induced apoptosis in neuroblastoma cells involves alterations in membrane fluidity.
- Intracellular calcium levels and oxygen free radicals play a role in this process.
- Extracellular calcium is crucial for dibucaine-induced apoptosis.