Determinants of Mitotic Catastrophe on Abrogation of the G2 DNA Damage Checkpoint by UCN-01

On, Kin Fan; Chen, Yue; Tang, Hoi; Chow, Jeremy P.H.; Poon, Randy Y. C.

doi:10.1158/1535-7163.mct-10-0809

Cited by 37 publications

(37 citation statements)

References 38 publications

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“…3E). Furthermore, linearity between the S-G 2 duration and mitotic duration implies a causal connection between the interphase state and subsequent mitotic state, providing an explanation to previous work that implicates CHK1i in activating the spindle assembly checkpoint (16).…”

Section: Delayed S Progression Is a Denominator Of Cytotoxicity Regasupporting

confidence: 64%

CHK1 Inhibition Synergizes with Gemcitabine Initially by Destabilizing the DNA Replication Apparatus

et al. 2015

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Combining cell-cycle checkpoint kinase inhibitors with the DNA-damaging chemotherapeutic agent gemcitabine offers clinical appeal, with a mechanistic rationale based chiefly on abrogation of gemcitabine-induced G 2 -M checkpoint activation. However, evidence supporting this mechanistic rationale from chemosensitization studies has not been consistent. Here we report a systematic definition of how pancreatic cancer cells harboring mutant p53 respond to this combination therapy, by combining mathematical models with large-scale quantitative biologic analyses of single cells and cell populations. Notably, we uncovered a dynamic range of mechanistic effects at different ratios of gemcitabine and CHK1 inhibitors. Remarkably, effective synergy was attained even where cells exhibited an apparently functional G 2 -M surveillance mechanism, as exemplified by a lack of both overt premature CDK1 activation and S-phase mitotic entry. Consistent with these findings, S-G 2 duration was extended in treated cells, leading to a definable set of lineage-dependent catastrophic fates. At synergistic drug concentrations, global replication stress was a distinct indicator of chemosensitization as characterized molecularly by an accumulation of S-phase cells with high levels of hyperphosphorylated RPA-loaded single-stranded DNA. In a fraction of these cells, persistent genomic damage was observed, including chromosomal fragmentation with a loss of centromeric regions that prevented proper kinetochore-microtubule attachment. Together, our results suggested a "foot-in-the-door" mechanism for drug synergy where cells were destroyed not by frank G 2 -M phase abrogation but rather by initiating a cumulative genotoxicity that deregulated DNA synthesis. Cancer Res; 75(17); 3583-95. Ó2015 AACR.

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Section: Delayed S Progression Is a Denominator Of Cytotoxicity Regasupporting

confidence: 64%

CHK1 Inhibition Synergizes with Gemcitabine Initially by Destabilizing the DNA Replication Apparatus

et al. 2015

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“…IR treatment followed by checkpoint abrogation in other cell lines, including H1299, HCT116, U2OS, induced significantly less mitotic catastrophe than HeLa cells (4). However, we found that monastrol was also able to sensitize H1299 cells after checkpoint abrogation (Fig.…”

Section: Discussionmentioning

confidence: 65%

“…Previously, we have used long-term time-lapse microscopy to track the fates of individual cells after the ionizing radiation (IR)-mediated G 2 DNA damage checkpoint is abrogated with the CHK1 inhibitor UCN-01 (4). We found that the extent of mitotic cell death is closely related to the duration of mitosis.…”

Section: Introductionmentioning

confidence: 99%

Inhibition of Eg5 Acts Synergistically with Checkpoint Abrogation in Promoting Mitotic Catastrophe

Chen

Chow

Poon

2012

Molecular Cancer Research

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The G 2 DNA damage checkpoint is activated by genotoxic agents and is particularly important for cancer therapies. Overriding the checkpoint can trigger precocious entry into mitosis, causing cells to undergo mitotic catastrophe. But some checkpoint-abrogated cells can remain viable and progress into G 1 phase, which may contribute to further genome instability. Our previous studies reveal that the effectiveness of the spindle assembly checkpoint and the duration of mitosis are pivotal determinants of mitotic catastrophe after checkpoint abrogation.In this study, we tested the hypothesis whether mitotic catastrophe could be enhanced by combining genotoxic stress, checkpoint abrogation, and the inhibition of the mitotic kinesin protein Eg5. We found that mitotic catastrophe induced by ionizing radiation and a CHK1 inhibitor (UCN-01) was exacerbated after Eg5 was inhibited with either siRNAs or monastrol. The combination of DNA damage, UCN-01, and monastrol sensitized cancer cells that were normally resistant to checkpoint abrogation. Importantly, a relatively low concentration of monastrol, alone not sufficient in causing mitotic arrest, was already effective in promoting mitotic catastrophe. These experiments suggest that it is possible to use sublethal concentrations of Eg5 inhibitors in combination with G 2 DNA damage checkpoint abrogation as an effective therapeutic approach. Mol Cancer Res; 10(5); 626-35. Ó2012 AACR.

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“…Individual colonies were isolated and propagated in the absence of puromycin. HeLa cells (7) or H1299, HCT116, or U2OS cells (19) stably expressing histone H2B-GFP were used for live cell imaging. The same approach was used to generate Hep3B cells expressing histone H2B-GFP.…”

Section: Methodsmentioning

confidence: 99%

Depletion of p31comet Protein Promotes Sensitivity to Antimitotic Drugs

Tang

Chan

Chen³

et al. 2012

Journal of Biological Chemistry

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Determinants of Mitotic Catastrophe on Abrogation of the G2 DNA Damage Checkpoint by UCN-01

Cited by 37 publications

References 38 publications

CHK1 Inhibition Synergizes with Gemcitabine Initially by Destabilizing the DNA Replication Apparatus

CHK1 Inhibition Synergizes with Gemcitabine Initially by Destabilizing the DNA Replication Apparatus

Inhibition of Eg5 Acts Synergistically with Checkpoint Abrogation in Promoting Mitotic Catastrophe

Depletion of p31comet Protein Promotes Sensitivity to Antimitotic Drugs

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