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Cell death by oxidative stress and ascorbic acid regeneration in human neuroectodermal cell lines
V De Laurenzi1, G Melino, I Savini
1Department of Experimental Medicine, University Tor Vergata, Rome, Italy.
Abstract:
In this paper, we show that human neuroectodermal cells exposed to 1-5 mM hydrogen peroxide or 10 nM-1 mM ascorbate die by programmed cell death induced by oxidative stress. The cell death by peroxide occurs within 4 h and involves approximately 80% of B-mel melanoma cells, while ascorbate causes cell death of approximately 86% of B-mel cells within 24 h. SK-N-BE(2) neuroblastoma cells are more resistant, 32% and 43% cell death for peroxide and ascorbate, respectively. In all cases, cell death causes hypodiploic DNA staining, evaluated by flow cytometry. Both cell lines can efficiently metabolise ascorbate due to significant levels of NADH-dependent semidehydroascorbate reductase and glutathione-dependent dehydroascorbate reductase. The cell death observed suggests a pro-oxidant, rather than anti-oxidant, role for ascorbic acid at physiological concentrations under these experimental conditions.
Insights
Oxidative stress from hydrogen peroxide and ascorbate induces programmed cell death in human neuroectodermal cells. Ascorbic acid acts as a pro-oxidant, causing significant cell death in melanoma and neuroblastoma cell lines.
Area of Science:
- Cell Biology
- Biochemistry
- Toxicology
Background:
- Oxidative stress is implicated in various cellular processes and diseases.
- Ascorbic acid (vitamin C) is typically considered an antioxidant, but its role can be context-dependent.
- Understanding the cellular response to oxidative agents is crucial for therapeutic and toxicological insights.
Purpose of the Study:
- To investigate the effects of hydrogen peroxide and ascorbate on human neuroectodermal cell viability.
- To determine the mechanism of cell death induced by these agents.
- To elucidate the role of ascorbic acid in cellular oxidative stress.
Main Methods:
- Exposure of B-mel melanoma and SK-N-BE(2) neuroblastoma cells to varying concentrations of hydrogen peroxide and ascorbate.
- Assessment of cell death using flow cytometry to evaluate DNA content (hypodiploidy).
- Enzymatic assays to measure the metabolic activity of ascorbate in cell lines.
Main Results:
- Hydrogen peroxide (1-5 mM) and ascorbate (10 nM-1 mM) induced programmed cell death in B-mel cells (approx. 80% and 86%, respectively).
- SK-N-BE(2) cells showed increased resistance to both agents (32% and 43% cell death).
- Cell death was characterized by hypodiploid DNA staining, and both cell lines efficiently metabolized ascorbate.
Conclusions:
- Ascorbic acid exhibits a pro-oxidant effect at physiological concentrations under experimental conditions, inducing programmed cell death.
- Oxidative stress from both hydrogen peroxide and ascorbate triggers cell death in human neuroectodermal cells.
- The differential sensitivity of cell lines suggests specific cellular mechanisms influencing response to oxidative agents.