Quantitative assessment of chromosome instability induced through chemical disruption of mitotic progression.
Most solid tumors are aneuploid, carrying an abnormal number of chromosomes, and they frequently missegregate whole chromosomes in a phenomenon termed chromosome instability (CIN). While CIN can be provoked through disruption of numerous mitotic pathways, it is not clear which of these mechanisms are most critical, or whether alternative mechanisms could also contribute significantly in vivo. One difficulty in determining the relative importance of candidate CIN regulators has been the lack of a straightforward, quantitative assay for CIN in live human cells: While gross mitotic abnormalities can be detected visually, moderate levels of CIN may not be obvious, and are thus problematic to measure. To address this issue, we have developed the first Human Artificial Chromosome (HAC)-based quantitative live-cell assay for mitotic chromosome segregation in human cells. We have produced U2OS-Phoenix cells carrying the alphoid(tetO)-HAC encoding copies of eGFP fused to the destruction box (DB) of anaphase promoting complex/cyclosome (APC/C) substrate hSecurin 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. U2OS-Phoenix cells show low inherent levels of CIN, which can be enhanced by agents that target mitotic progression through distinct mechanisms. This assay allows direct detection of CIN induced by clinically important agents without conspicuous mitotic defects, allowing us to score increased levels of CIN that fall below the threshold required for discernable morphological disruption.
a Division of Molecular and Cellular Biology, National Institute of Child Health and Human Development , National Institutes of Health , Bethesda , MD , USA.
Sarine
S
Markossian
a Division of Molecular and Cellular Biology, National Institute of Child Health and Human Development , National Institutes of Health , Bethesda , MD , USA.
Alexei
A
Arnaoutov
b Section of Hematology and Medical Oncology, Department of Medicine , Tulane University , New Orleans , LA , USA.
Nakhle S
NS
Saba
c Developmental Therapeutic Branch, National Cancer Institute , National Institutes of Health , Bethesda , MD , USA.
Vladimir
V
Larionov
a Division of Molecular and Cellular Biology, National Institute of Child Health and Human Development , National Institutes of Health , Bethesda , MD , USA.
Mary
M
Dasso
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D016466:CHO Cells; D045744:Cell Line, Tumor; D002469:Cell Separation; D043171:Chromosomal Instability / Q000187:drug effects / Q000235:genetics*; D020090:Chromosome Segregation / Q000187:drug effects; D022222:Chromosomes, Artificial, Human / Q000235:genetics; D006224:Cricetinae; D003412:Cricetulus; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D008938:Mitosis / Q000187:drug effects / Q000235:genetics*
D000970:Antineoplastic Agents; D049452:Green Fluorescent Proteins
aneuploidy; assay development; chromosome instability (CIN); chromosome segregation; human artificial chromosome (HAC)