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Different G2/M accumulation in M059J and M059K cells after exposure to DNA double-strand break-inducing agents
Asa Holgersson1, Thomas Heiden, Juan Castro
1Department of Oncology-Pathology, Unit of Medical Radiation Biology, Karolinska Institutet, SE-171 76 Stockholm, Sweden.
Purpose:
To investigate and compare the cell cycle progression in relation to cell death in the human glioma cell lines, M059J and M059K, after exposure to DNA double-strand break-inducing agents.
Methods And Materials:
The M059J and M059K cells, deficient and proficient in the catalytic subunit of the DNA-dependent protein kinase, respectively, were exposed to 1 and 4 Gy of photons or accelerated nitrogen ions. In addition, M059J and M059K cells were treated with 10 and 40 mug/mL of bleomycin for 30 min, respectively. Cell cycle progression, monitored by DNA flow cytometry, was measured up to 72 h after treatment.
Results:
M059J, but not M059K, cells displayed G(2)/M accumulation after low linear energy transfer irradiation. High linear energy transfer radiation exposure however, resulted in a substantial increase of M059K cells in the G(2)/M phase detected at 48 h. At 72 h, the number of cells in the G(2)/M phase was equivalent to its control. M059J cells accumulated mainly in S phase after high linear energy transfer irradiation. In contrast to M059K, M059J cells were still blocked at 72 h. Bleomycin induced G(2)/M accumulation for both M059J and M059K cells detected 24 h after treatment. At 48 h, the percentage of bleomycin-treated M059J cells in G(2)/M phase remained high, and the number of M059K cells had decreased to control levels. Neither cell line showed cell cycle arrest (< or =10 h) after exposure to these agents.
Conclusion:
Distinct cell cycle block and release is dependent on the complexity of the induced DNA damage and the presence of the DNA-dependent protein kinase catalytic subunit.
Insights
Human glioma cells M059J and M059K showed distinct cell cycle responses to DNA double-strand break agents. Cell cycle arrest and progression depend on DNA damage complexity and DNA-dependent protein kinase presence.
Area of Science:
- Molecular Biology
- Cell Biology
- Radiation Oncology
Background:
- Glioma cell lines M059J (DNA-dependent protein kinase deficient) and M059K (proficient) are valuable models for DNA repair studies.
- Understanding cell cycle regulation is crucial for predicting cellular responses to DNA damage and developing targeted therapies.
Purpose of the Study:
- To compare cell cycle progression and cell death in M059J and M059K human glioma cells.
- To investigate the impact of DNA double-strand break-inducing agents on cell cycle dynamics.
- To elucidate the role of DNA-dependent protein kinase in cellular response to DNA damage.
Main Methods:
- M059J and M059K cells were exposed to varying doses of photon or nitrogen ion radiation (1 and 4 Gy).
- Cells were also treated with bleomycin (10 and 40 µg/mL).
- Cell cycle progression was monitored using DNA flow cytometry up to 72 hours post-treatment.
Main Results:
- M059J cells showed G2/M accumulation after low-LET irradiation, while M059K cells exhibited G2/M increase after high-LET radiation.
- High-LET radiation caused M059J cells to accumulate in S phase, with prolonged arrest compared to M059K.
- Bleomycin induced G2/M accumulation in both cell lines, with M059J showing sustained arrest.
Conclusions:
- Cell cycle arrest and release patterns are distinct between M059J and M059K cells.
- The complexity of DNA damage and the presence of DNA-dependent protein kinase catalytic subunit significantly influence cell cycle outcomes.
- These findings highlight the differential response of glioma cells to DNA-damaging agents based on their DNA repair capacity.
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