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Induction of apoptosis by a dominant negative H-RAS mutant (116Y) in K562 cells
1Laboratory of Molecular Genetics, Hokkaido University School of Medicine, Japan.
Abstract:
Recent extensive work on apoptosis has begun to reveal its molecular mechanisms. Several genes that regulate apoptosis have been identified. Among them, the BCL2 gene is considered to be an important gene that inhibits apoptosis. However, there must be other genes, yet to be identified, which suppress apoptosis. It has been suggested that the activation of RAS function by BCR-ABL fusion protein in chronic myelogenous leukemia may be an important mechanism in the BCR-ABL mediated transformation. Therefore, in this study we have investigated whether the suppression of endogenous H-RAS function inhibits the BCR-ABL mediated transforming activity in a K562 human chronic myelogenous leukemia cell line. The induced expression of a dominant negative v-H-RAS mutant (116Y) in K562 cells has resulted in cell death. The morphological characteristics and the detection of fragmented DNA by gel electrophoresis in the dead cells have revealed that this cell death is apoptosis. These results directly indicate that the RAS gene as well as the BCL2 gene has an ability to suppress apoptosis.
Insights
The RAS gene, like BCL2, can suppress apoptosis. Inhibiting RAS function in chronic myelogenous leukemia cells induced programmed cell death, indicating its role in cancer cell survival.
Area of Science:
- Molecular Biology
- Cancer Research
- Cell Death Pathways
Background:
- Extensive research has elucidated molecular mechanisms of apoptosis.
- BCL2 is a known inhibitor of apoptosis, but other suppressors likely exist.
- BCR-ABL fusion protein's RAS activation is implicated in chronic myelogenous leukemia transformation.
Purpose of the Study:
- Investigate if suppressing endogenous H-RAS function affects BCR-ABL mediated transformation.
- Determine the role of RAS in apoptosis within chronic myelogenous leukemia.
Main Methods:
- Utilized K562 human chronic myelogenous leukemia cell line.
- Induced expression of a dominant-negative v-H-RAS mutant (116Y).
- Assessed cell death via morphology and DNA fragmentation (gel electrophoresis).
Main Results:
- Induced expression of v-H-RAS mutant led to significant cell death in K562 cells.
- Morphological and DNA fragmentation analyses confirmed apoptosis.
- RAS gene demonstrated an ability to suppress apoptosis, similar to BCL2.
Conclusions:
- RAS gene functions as an apoptosis suppressor.
- RAS pathway is crucial for BCR-ABL mediated transformation in chronic myelogenous leukemia.
- Findings identify RAS as a potential therapeutic target in leukemia.