BUB1 mediation of caspase-independent mitotic death determines cell fate

Authors:
Niikura Y, Dixit A, Scott R, Perkins G, Kitagawa K
In:
Source: J Cell Biol
Publication Date: (2007)
Issue: 178(2): 283-96
Research Area:
Cancer Research/Cell Biology
Cells used in publication:
Caco-2
Species: human
Tissue Origin: colon
HT-29
Species: human
Tissue Origin: colon
SW480
Species: human
Tissue Origin: colon
Platform:
Nucleofectorâ„¢ I/II/2b
Abstract
The spindle checkpoint that monitors kinetochore-microtubule attachment has been implicated in tumorigenesis; however, the relation between the spindle checkpoint and cell death remains obscure. In BUB1-deficient (but not MAD2-deficient) cells, conditions that activate the spindle checkpoint (i.e., cold shock or treatment with nocodazole, paclitaxel, or 17-AAG) induced DNA fragmentation during early mitosis. This mitotic cell death was independent of caspase activation; therefore, we named it caspase-independent mitotic death (CIMD). CIMD depends on p73, a homologue of p53, but not on p53. CIMD also depends on apoptosis-inducing factor and endonuclease G, which are effectors of caspase-independent cell death. Treatment with nocodazole, paclitaxel, or 17-AAG induced CIMD in cell lines derived from colon tumors with chromosome instability, but not in cells from colon tumors with microsatellite instability. This result was due to low BUB1 expression in the former cell lines. When BUB1 is completely depleted, aneuploidy rather than CIMD occurs. These results suggest that cells prone to substantial chromosome missegregation might be eliminated via CIMD.