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Apoptosis: mode of cell death induced in T cell leukemia lines by dexamethasone and other agents
N Bansal1, A Houle, G Melnykovych
1Department of Veterans Affairs Medical Center, Kansas City, Missouri 64128.
Abstract:
Glucocorticoids can mediate the destruction of thymocytes and T cell-derived leukemia cells through a mechanism known as apoptosis. The characteristic feature of apoptosis is fragmentation of DNA at internucleosomal linkers through the activity of a specific endonuclease. In this study, an attempt was made to compare dexamethasone-induced apoptosis in two T cell-derived human leukemia lines (CEM-C1 and CEM-C7) to the cell killing brought about by selected cytotoxic agents. In the CEM-C7 cell line (dexamethasone-sensitive), apoptosis was induced not only by dexamethasone but by actinomycin D, cycloheximide, and 25-OH cholesterol. In the CEM-C1 cell line (dexamethasone-resistant) cycloheximide, 25-OH cholesterol, or cell starvation could induce apoptosis. It appears that in leukemic cells apoptosis may be induced by a variety of unrelated toxic agents and is not limited to glucocorticoids.
Insights
Glucocorticoids induce apoptosis in leukemia cells. This study shows various toxic agents can trigger apoptosis in T cell leukemia, not just glucocorticoids, highlighting broader cell death mechanisms.
Area of Science:
- Cell Biology
- Molecular Biology
- Cancer Research
Background:
- Glucocorticoids are known to induce apoptosis in thymocytes and T cell leukemia.
- Apoptosis is characterized by DNA fragmentation mediated by specific endonucleases.
- Understanding apoptosis induction in leukemia is crucial for developing targeted therapies.
Purpose of the Study:
- To compare dexamethasone-induced apoptosis in two human leukemia cell lines (CEM-C1 and CEM-C7).
- To investigate the effects of other cytotoxic agents on apoptosis induction in these cell lines.
- To determine if apoptosis induction in leukemia is exclusive to glucocorticoids.
Main Methods:
- Utilized two human T cell-derived leukemia lines: CEM-C1 (dexamethasone-resistant) and CEM-C7 (dexamethasone-sensitive).
- Exposed cells to dexamethasone, actinomycin D, cycloheximide, 25-OH cholesterol, and induced cell starvation.
- Monitored and compared the induction of apoptosis across different treatment groups.
Main Results:
- In dexamethasone-sensitive CEM-C7 cells, apoptosis was induced by dexamethasone, actinomycin D, cycloheximide, and 25-OH cholesterol.
- In dexamethasone-resistant CEM-C1 cells, apoptosis was induced by cycloheximide, 25-OH cholesterol, and cell starvation.
- Demonstrated that multiple unrelated toxic agents can induce apoptosis in leukemia cells.
Conclusions:
- Apoptosis in T cell-derived leukemia can be triggered by a diverse range of unrelated toxic agents.
- The induction of apoptosis in leukemia is not solely limited to glucocorticoids.
- These findings suggest broader therapeutic strategies targeting apoptosis in leukemia are possible.