p53 induces senescence in the unstable progeny of aneuploid cells

Abstract

Aneuploidy is the condition of having an imbalanced karyotype, which is strongly associated with tumor initiation, evolution, and acquisition of drug-resistant features, possibly by generating heterogeneous populations of cells with distinct genotypes and phenotypes. Multicellular eukaryotes have therefore evolved a range of extrinsic and cell-autonomous mechanisms for restraining proliferation of aneuploid cells, including activation of the tumor suppressor protein p53. However, accumulating evidence indicates that a subset of aneuploid cells can escape p53mediated growth restriction and continue proliferating in vitro. Here we show that such aneuploid cell lines display a robust modal karyotype and low frequency of chromosomal aberrations despite ongoing chromosome instability. Indeed, while these aneuploid cells are able to survive for extended periods in vitro, their chromosomally unstable progeny remain subject to p53-induced senescence and growth restriction, leading to subsequent elimination from the aneuploid pool. This mechanism helps maintain low levels of heterogeneity in aneuploid populations and may prevent detrimental evolutionary processes such as cancer progression and development of drug resistance.

On the role of p53 in the cellular response to aneuploidy

“…Studies in recent years have further suggested roles for p53 in limiting the proliferation of aneuploid cells. However, these studies were limited to established human cell lines that were chromosomally stable and near diploid, such as RPE1, an hTERT-immortalized retinal pigmented epithelial cell line; HCT116, a colon carcinoma cell line; and a few other cell lines ( Cianchi et al, 1999 ; Giam et al, 2019 ; Hinchcliffe et al, 2016 ; Janssen et al, 2011 ; Kurinna et al, 2013 ; Li et al, 2010 ; Potapova et al, 2016 ; Santaguida et al, 2017 ; Soto et al, 2017 ; Thompson and Compton, 2010 ). Recent studies also revealed complex interplay between p53 and several other genome-protective proteins, such as p38, H3.3, and BCL9L ( Hinchcliffe et al, 2016 ; López-García et al, 2017 ; Simões-Sousa et al, 2018 ).…”

Extensive protein dosage compensation in aneuploid human cancers

“…Despite these findings, aneuploidy itself has also been observed to induce substantial tumor suppressive stresses 10,22,23 . Aneuploid cells have increased metabolic requirements [24][25][26][27][28][29] , display high levels of senescence 23,[30][31][32][33] , exhibit significant genomic instability 34,35 , and are sensitive to compounds that interfere with protein folding and turnover 28,[36][37][38] . Aneuploidy-associated stresses may be caused by the deregulation of gene expression, which leads to the imbalanced production of key cellular proteins.…”

Non‐genetic and genetic rewiring underlie adaptation to hypomorphic alleles of an essential gene

“…Cells grown to ∼ 80% confluency were treated with 100 ng/ml Colcemid solution (Gibco) for 3 h, collected by trypsinization, and centrifuged at 1,000 rpm for 10 min (Giam et al , 2020). Cell pellets were resuspended in 75 mM potassium chloride solution and incubated for 15 min in a 37°C waterbath.…”

“…Metaphase preparations (described above and in Giam et al , 2020) or interphase cells were dropped onto glass slides and co‐denatured with XA 13/18/21 AneuScore probe mix (MetaSystems) for chromosome copy number, or with NUP58‐20‐GR/NUP58‐20‐OR (Empire Genomics) for focal amplification detection. Slides were incubated at 75°C for 2 min before being placed in a humidified slide incubator (Eppendorf) at 37°C for 24 h. Following hybridization, slides were washed first in 0.4X SSC (pH 7.0) at 72°C for 2 min, then in 2× SSC/0.05% Tween 20 (pH 7.0) at room temperature for 30 s, rinsed briefly in distilled water, and mounted on microscope slides with fluorescence mounting media (Dako) together with DAPI.…”