Quantitative assessment of chromosome instability induced through chemical disruption of mitotic progression

FARE Award Winner

Authors

• S Markossian
• A Arnaoutov
• V Larionov
• M Dasso

Abstract

Most solid tumors are aneuploid, carrying an abnormal number of chromosomes, and they frequently missegregate whole chromosomes in a phenomenon termed chromosome instability (CIN). Despite its importance in cancer etiology, there are no straightforward, quantitative assays for CIN in cancer. To address this problem, we have developed the first Human Artificial Chromosome (HAC)-based quantitative live-cell assay for mitotic chromosome segregation in human cells, with which we can score the rates of CIN within one cell division. We have produced U2OS-Phoenix cells carrying a HAC encoding copies of eGFP fused to the destruction box (DB) of anaphase promoting complex/cyclosome (APC/C) substrate hSecurin, tet operator (tetO) arrays, and sequences encoding the tetracycline repressor fused to mCherry (TetR-mCherry). Upon HAC missegregation, daughter cells that do not obtain a copy of the HAC are GFP negative in the subsequent interphase. The HAC can also be monitored live following the TetR-mcherry signal. Following the HAC by live cell imaging experiments, we show that U2OS-Phoenix cells have low inherent levels of CIN, but HAC missegregation is markedly increased by treatment with agents that target mitotic progression through distinct mechanisms such as Reversine, an inhibitor of Mps1, and microtubule agents Nocodazole and Taxol. In summary, we have developed new assays to score CIN levels in human cells and have shown that CIN levels increase upon treatment with chemotherapeutic agents, which makes our assays ideal for chemical screens.

Scientific Focus Area: Cell Biology

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