The consequences of tetraploidy in mammalian cells


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Kuan-Chung Su1, Mark Petronczki1
1CRUK LRI, Potters Bar, United Kingdom

Background

Cytokinesis is the final step during cell division that ensures the proper partitioning of the segregated genomes into the daughter cells. Cytokinesis failure can lead to aneuploidy and chromosomal instability. In our studies we are focusing on understanding the molecular mechanism of cytokinesis and the cellular consequences of cytokinesis failure

Method

We have established efficient methods to generate tetraploid cells by inhibiting cytokinesis in vitro. We could confirm that tetraploid cells continue to efficiently replicate DNA after cytokinesis failure without arresting in G1.

Results

Using long-term time-lapse microscopy we observed a delay in of the length of the cell cycle in offspring of tetraploid cancer cells. We have established a PCNA-EGFP based cell line that would allow us to identify the cell cycle stage at which the delay occurs. We are now moving now our analysis of cellular responses towards normal or chromosomal stable cancer cells (e.g. HCT-116).

Conclusion

Using siRNA-mediated depletion of essential cytokinetic regulators, we were able to induce tetraploidy in murine NIH3T3 cells. shRNA hairpin constructs are currently being developed to generate a system that can block cytokinesis transiently and allow the analysis of the consequences of tetraploidy inĀ vivo.