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Proliferation of aneuploid human cells is limited by a p53-dependent mechanism.

Thompson SL, Compton DA - J. Cell Biol. (2010)

Bottom Line: However, the relationship of aneuploidy and CIN is unclear because the proliferation of cultured diploid cells is compromised by chromosome missegregation.The mechanism for this intolerance of nondiploid genomes is unknown.These data fit with the concordance of aneuploidy and disruption of the p53 pathway in many tumors, but the presence of aneuploid cells in some normal human and mouse tissues indicates that there are known exceptions to the involvement of p53 in aneuploid cells and that tissue context may be important in how cells respond to aneuploidy.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biochemistry, Dartmouth Medical School, Hanover, NH 03755, USA.

ABSTRACT
Most solid tumors are aneuploid, and it has been proposed that aneuploidy is the consequence of an elevated rate of chromosome missegregation in a process called chromosomal instability (CIN). However, the relationship of aneuploidy and CIN is unclear because the proliferation of cultured diploid cells is compromised by chromosome missegregation. The mechanism for this intolerance of nondiploid genomes is unknown. In this study, we show that in otherwise diploid human cells, chromosome missegregation causes a cell cycle delay with nuclear accumulation of the tumor suppressor p53 and the cyclin kinase inhibitor p21. Deletion of the p53 gene permits the accumulation of nondiploid cells such that CIN generates cells with aneuploid genomes that resemble many human tumors. Thus, the p53 pathway plays an important role in limiting the propagation of aneuploid human cells in culture to preserve the diploid karyotype of the population. These data fit with the concordance of aneuploidy and disruption of the p53 pathway in many tumors, but the presence of aneuploid cells in some normal human and mouse tissues indicates that there are known exceptions to the involvement of p53 in aneuploid cells and that tissue context may be important in how cells respond to aneuploidy.

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p53- HCT116 cells continue to proliferate after missegregation of chromosomes. p53 wild-type (left) and  (right) cells were treated with or without (control) monastrol, and mitotic cells were collected by shake-off, plated, and allowed to proliferate with no further treatment. At 4 h, 2 d, and 6 d, cells were harvested, and FISH was performed using probes specific for chromosomes 3, 7, and 15. For each time point/condition, 600 nuclei were counted per chromosome. Bars represent the mean percent deviation from the modal chromosome number, and error bars show SEM. *, P < 0.05; χ2 test.
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fig5: p53- HCT116 cells continue to proliferate after missegregation of chromosomes. p53 wild-type (left) and (right) cells were treated with or without (control) monastrol, and mitotic cells were collected by shake-off, plated, and allowed to proliferate with no further treatment. At 4 h, 2 d, and 6 d, cells were harvested, and FISH was performed using probes specific for chromosomes 3, 7, and 15. For each time point/condition, 600 nuclei were counted per chromosome. Bars represent the mean percent deviation from the modal chromosome number, and error bars show SEM. *, P < 0.05; χ2 test.

Mentions: If the stabilization of p53 contributes to the prolonged cell cycle delay after chromosome missegregation, loss of p53 would permit the growth of aneuploid cells. To test this idea, we induced chromosome missegregation using a single monastrol washout in HCT116 cells lacking both alleles of the p53 gene (Bunz et al., 2002). We then determined the chromosome content of these cells as they propagated without further treatment using FISH with chromosome-specific probes (Fig. 5). The percentage of untreated p53- cells that were aneuploid in the population was low and equivalent to wild-type HCT116 cells. Immediately after washout of monastrol, there was an equivalent increase in the percentage of aneuploid cells in both populations. The percentage of aneuploid cells in HCT116 wild-type populations returned to basal levels by 6 d after treatment (Fig. 5), as previously shown (Thompson and Compton, 2008), indicating a failure of aneuploid cells to propagate efficiently. In contrast, the percentage of aneuploid cells in the population of HCT116 cells lacking p53 remained high 6 d after treatment, indicating that aneuploid cells in this population propagate and compete efficiently with diploid cells. This demonstrates that p53 is a key component of a pathway that provides intolerance to aneuploidy in somatic cultured human cells.


Proliferation of aneuploid human cells is limited by a p53-dependent mechanism.

Thompson SL, Compton DA - J. Cell Biol. (2010)

p53- HCT116 cells continue to proliferate after missegregation of chromosomes. p53 wild-type (left) and  (right) cells were treated with or without (control) monastrol, and mitotic cells were collected by shake-off, plated, and allowed to proliferate with no further treatment. At 4 h, 2 d, and 6 d, cells were harvested, and FISH was performed using probes specific for chromosomes 3, 7, and 15. For each time point/condition, 600 nuclei were counted per chromosome. Bars represent the mean percent deviation from the modal chromosome number, and error bars show SEM. *, P < 0.05; χ2 test.
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2819684&req=5

fig5: p53- HCT116 cells continue to proliferate after missegregation of chromosomes. p53 wild-type (left) and (right) cells were treated with or without (control) monastrol, and mitotic cells were collected by shake-off, plated, and allowed to proliferate with no further treatment. At 4 h, 2 d, and 6 d, cells were harvested, and FISH was performed using probes specific for chromosomes 3, 7, and 15. For each time point/condition, 600 nuclei were counted per chromosome. Bars represent the mean percent deviation from the modal chromosome number, and error bars show SEM. *, P < 0.05; χ2 test.
Mentions: If the stabilization of p53 contributes to the prolonged cell cycle delay after chromosome missegregation, loss of p53 would permit the growth of aneuploid cells. To test this idea, we induced chromosome missegregation using a single monastrol washout in HCT116 cells lacking both alleles of the p53 gene (Bunz et al., 2002). We then determined the chromosome content of these cells as they propagated without further treatment using FISH with chromosome-specific probes (Fig. 5). The percentage of untreated p53- cells that were aneuploid in the population was low and equivalent to wild-type HCT116 cells. Immediately after washout of monastrol, there was an equivalent increase in the percentage of aneuploid cells in both populations. The percentage of aneuploid cells in HCT116 wild-type populations returned to basal levels by 6 d after treatment (Fig. 5), as previously shown (Thompson and Compton, 2008), indicating a failure of aneuploid cells to propagate efficiently. In contrast, the percentage of aneuploid cells in the population of HCT116 cells lacking p53 remained high 6 d after treatment, indicating that aneuploid cells in this population propagate and compete efficiently with diploid cells. This demonstrates that p53 is a key component of a pathway that provides intolerance to aneuploidy in somatic cultured human cells.

Bottom Line: However, the relationship of aneuploidy and CIN is unclear because the proliferation of cultured diploid cells is compromised by chromosome missegregation.The mechanism for this intolerance of nondiploid genomes is unknown.These data fit with the concordance of aneuploidy and disruption of the p53 pathway in many tumors, but the presence of aneuploid cells in some normal human and mouse tissues indicates that there are known exceptions to the involvement of p53 in aneuploid cells and that tissue context may be important in how cells respond to aneuploidy.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biochemistry, Dartmouth Medical School, Hanover, NH 03755, USA.

ABSTRACT
Most solid tumors are aneuploid, and it has been proposed that aneuploidy is the consequence of an elevated rate of chromosome missegregation in a process called chromosomal instability (CIN). However, the relationship of aneuploidy and CIN is unclear because the proliferation of cultured diploid cells is compromised by chromosome missegregation. The mechanism for this intolerance of nondiploid genomes is unknown. In this study, we show that in otherwise diploid human cells, chromosome missegregation causes a cell cycle delay with nuclear accumulation of the tumor suppressor p53 and the cyclin kinase inhibitor p21. Deletion of the p53 gene permits the accumulation of nondiploid cells such that CIN generates cells with aneuploid genomes that resemble many human tumors. Thus, the p53 pathway plays an important role in limiting the propagation of aneuploid human cells in culture to preserve the diploid karyotype of the population. These data fit with the concordance of aneuploidy and disruption of the p53 pathway in many tumors, but the presence of aneuploid cells in some normal human and mouse tissues indicates that there are known exceptions to the involvement of p53 in aneuploid cells and that tissue context may be important in how cells respond to aneuploidy.

Show MeSH
Related in: MedlinePlus