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Updated: Jun 20, 2026
Visualizing and Quantifying Endonuclease-Based Site-Specific DNA Damage
Published on: August 21, 2021
DNA damage-induced cell death is enhanced by progression through mitosis
Hanne Varmark1, Cynthia A Sparks, Joshua J Nordberg
1Program in Cell and Developmental Dynamics and Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA.
Abstract:
Progression through the G(2)/M transition following DNA damage is linked to cytokinesis failure and mitotic death. In four different transformed cell lines and two human embryonic stem cell lines, we find that DNA damage triggers mitotic chromatin decondensation and global phosphorylation of histone H2AX, which has been associated with apoptosis. However, extended time-lapse studies in HCT116 colorectal cancer cells indicate that death does not take place during mitosis, but 72% of cells die within 3 days of mitotic exit. By contrast, only 11% of cells in the same cultures that remained in interphase died, suggesting that progression through mitosis enhances cell death following DNA damage. These time-lapse studies also confirmed that DNA damage leads to high rates of cytokinesis failure, but showed that cells that completed cytokinesis following damage died at higher rates than cells that failed to complete division. Therefore, post-mitotic cell death is not a response to cytokinesis failure or polyploidy. We also show that post-mitotic cell death is largely independent of p53 and is only partially suppressed by the apical caspase inhibitor Z-VAD-FMK. These findings suggest that progression through mitosis following DNA damage initiates a p53- and caspase-independent cell death response that prevents propagation of genetic lesions.
Insights
DNA damage triggers cell death after mitosis, not during, and this process is independent of p53 and caspases, preventing genetic lesion propagation.
Area of Science:
- Cell Biology
- Genetics
- Molecular Biology
Background:
- DNA damage response pathways are critical for maintaining genomic stability.
- Mitotic progression after DNA damage can lead to cell death, but the precise mechanisms and timing remain unclear.
Purpose of the Study:
- To investigate the timing and mechanisms of cell death following DNA damage and mitotic progression.
- To determine if post-mitotic cell death is linked to cytokinesis failure or polyploidy.
- To elucidate the roles of p53 and caspases in DNA damage-induced post-mitotic cell death.
Main Methods:
- Extended time-lapse microscopy of HCT116 colorectal cancer cells and other cell lines.
- Analysis of DNA damage markers, including histone H2AX phosphorylation.
- Assessment of cytokinesis, polyploidy, p53, and caspase activity.
Main Results:
- DNA damage induces mitotic chromatin decondensation and histone H2AX phosphorylation.
- Cell death predominantly occurs within 3 days after mitotic exit, not during mitosis.
- Post-mitotic cell death is independent of cytokinesis failure, polyploidy, p53, and largely caspase activity.
Conclusions:
- Progression through mitosis following DNA damage initiates a p53- and caspase-independent cell death pathway.
- This post-mitotic cell death mechanism prevents the propagation of genetic lesions.
- Understanding this pathway offers insights into cancer therapy and genomic integrity maintenance.
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