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Updated: Jul 5, 2026
05:29
Measuring Caspase Activity Using a Fluorometric Assay or Flow Cytometry
Published on: March 24, 2023
Caspase-independent mitotic death (CIMD).
Katsumi Kitagawa1, Yohei Niikura
1Department of Molecular Pharmacology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA. katsumi.kitagawa@stjude.org
Cell Cycle (Georgetown, Tex.)
|April 17, 2008
Summary
A novel cell death pathway, caspase-independent mitotic death (CIMD), prevents aneuploidy by eliminating cells with faulty spindle checkpoints. This discovery impacts cancer research and understanding of chromosome instability.
Area of Science:
- Cell Biology
- Genetics
- Molecular Biology
Background:
- The spindle checkpoint ensures accurate chromosome transmission, preventing aneuploidy which can lead to cancer.
- The mechanism preventing aneuploidy due to spindle checkpoint failure remains largely unknown.
Purpose of the Study:
- To identify the cell death mechanism that prevents aneuploidy caused by spindle checkpoint failure.
- To characterize a novel form of cell death termed caspase-independent mitotic death (CIMD).
Main Methods:
- Investigated BUB1-deficient and MAD2-deficient cells under spindle checkpoint-activating conditions (cold shock, nocodazole, paclitaxel, 17-AAG).
- Assessed the roles of p73, p53, apoptosis-inducing factor (AIF), and endonuclease G (Endo G) in CIMD.
- Examined the consequences of complete BUB1 depletion on chromosome segregation and cell death.
Main Results:
- Identified CIMD, a novel caspase-independent cell death, induced in BUB1-deficient cells under spindle checkpoint activation.
- CIMD requires p73, AIF, and Endo G, but not p53.
- Complete BUB1 depletion leads to aneuploidy instead of CIMD, suggesting CIMD prevents chromosome missegregation.
- Mitotic index monitoring may be misleading for evaluating spindle checkpoint activity in mutant or cancer cells.
Conclusions:
- CIMD acts as a protective mechanism against aneuploidy by eliminating cells with defective spindle checkpoints and high risk of chromosome missegregation.
- Findings challenge previous methods of assessing spindle checkpoint function and have implications for cancer biology.
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