The structure of the human cell cycle

Stallaert, Wayne; Kedziora, Katarzyna M.; Taylor, Colin D.; Zikry, Tarek M.; Sobon, Holly K.; Taylor, Sovanny R.; Young, Catherine L.; Limas, Juanita C.; Cook, Jeanette Gowen; Purvis, Jeremy E.

doi:10.1101/2021.02.11.430845

Cited by 8 publications

(7 citation statements)

References 56 publications

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“…We experimentally validated our methodology in nine lung adenocarcinoma cell lines. There was a remarkably good correlation between our predicted quiescence levels and the fraction of quiescent cells, estimated using quantitative, single-cell imaging of phospho-Ser807/811-Rb (PRb, which labels proliferative cells 38 ) and 24 hour EdU proliferation assays (Figure 1e-h). Cells that were negative for either PRb or EdU were defined as quiescent (see Methods, Figure 1e-f).…”

Section: Evaluating Tumour Dormancy From Transcriptomic Datamentioning

confidence: 53%

Genomic hallmarks and therapeutic implications of G0 cell cycle arrest in cancer

Wiecek

Cutty

Kornai

et al. 2021

Preprint

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Therapy resistance in cancer is often driven by a subpopulation of cells that are temporarily arrested in a non-proliferative, quiescent or ‘dormant’ state, which is difficult to capture and whose mutational drivers remain largely unknown. We developed methodology to uniquely identify this state from transcriptomic signals and characterised its prevalence and genomic constraints in solid primary tumours. We show dormancy preferentially emerges in the context of more stable, less mutated genomes which maintain TP53 integrity and lack the hallmarks of DNA damage repair deficiency, while presenting increased APOBEC mutagenesis. We uncover novel genomic dependencies of this process, including the amplification of the centrosomal gene CEP89 as a driver of dormancy impairment. Lastly, we demonstrate that dormancy underlies unfavourable responses to various therapies exploiting cell cycle, kinase signalling and epigenetic mechanisms in single cell data, and propose a signature of dormancy-linked therapeutic resistance to further study and clinically track this state.

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Section: Evaluating Tumour Dormancy From Transcriptomic Datamentioning

confidence: 53%

Genomic hallmarks and therapeutic implications of G0 cell cycle arrest in cancer

Wiecek

Cutty

Kornai

et al. 2021

Preprint

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“…To determine whether endogenous Cdt1 is degraded over a similar time window in early S phase, we utilized a combined quantitative image-based cytometry (QIBC) (Toledo et al, 2013) and live-cell imaging approach (Cappell et al, 2016; Spencer et al, 2013). In this method, we identified the S phase entry time for each cell using automated live-cell imaging of fluorescent cell cycle reporters prior to cell fixation, and identified the same cells in QIBC analysis (Cappell et al, 2016, 2018; Gookin et al, 2017; Stallaert et al, 2021). This method allowed us to retrospectively synchronize fixed-cell measurements of thousands of cells based on the elapsed time from S phase start with high temporal resolution (Figure 1C).…”

Section: Resultsmentioning

confidence: 99%

Cdt1 inhibits CMG helicase in early S phase to separate origin licensing from DNA synthesis

Ratnayeke

Chung

Meyer

2021

Preprint

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A fundamental concept in eukaryotic DNA replication is the temporal separation of G1 origin licensing from S phase origin firing. Re-replication and genome instability ensue if licensing occurs after DNA synthesis has started. In humans and other vertebrates, the E3 ubiquitin ligase CRL4Cdt2 starts to degrade the licensing factor Cdt1 after origins fire, raising the question of how cells prevent re-replication in early S phase. Here, using quantitative microscopy, we show that Cdt1 inhibits DNA synthesis during an overlap period when cells fire origins while Cdt1 is still present. Cdt1 inhibits DNA synthesis by suppressing CMG helicase progression at replication forks through the MCM-binding domain of Cdt1, and DNA synthesis commences once Cdt1 is degraded. Thus, instead of separating licensing from firing to prevent re-replication in early S phase, cells separate licensing from DNA synthesis through Cdt1-mediated inhibition of CMG helicase after firing.

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“…Quantification of DNA content by Hoechst sum intensity allows the gating of cells into G1, S and G2/M phases (electronic supplementary material, figure S2b) [15]. P-Rb is bimodally distributed in a population of asynchronously cycling cells, reflecting the proliferation status of the population with G0 cells (and palbociclib-arrested cells) displaying hypophosphorylated Rb [52][53][54] (electronic supplementary material, figure S2c).…”

Section: P21 and P27 Are Not Required For Entry Into G1 Arrest With Palbociclib In Rpe1 Cellsmentioning

confidence: 99%

Palbociclib-mediated cell cycle arrest can occur in the absence of the CDK inhibitors p21 and p27

Pennycook

Barr

2021

Open Biol.

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The use of CDK4/6 inhibitors in the treatment of a wide range of cancers is an area of ongoing investigation. Despite their increasing clinical use, there is limited understanding of the determinants of sensitivity and resistance to these drugs. Recent data have cast doubt on how CDK4/6 inhibitors arrest proliferation, provoking renewed interest in the role(s) of CDK4/6 in driving cell proliferation. As the use of CDK4/6 inhibitors in cancer therapies becomes more prominent, an understanding of their effect on the cell cycle becomes more urgent. Here, we investigate the mechanism of action of CDK4/6 inhibitors in promoting cell cycle arrest. Two main models explain how CDK4/6 inhibitors cause G1 cell cycle arrest, which differ in their dependence on the CDK inhibitor proteins p21 and p27. We have used live and fixed single-cell quantitative imaging, with inducible degradation systems, to address the roles of p21 and p27 in the mechanism of action of CDK4/6 inhibitors. We find that CDK4/6 inhibitors can initiate and maintain a cell cycle arrest without p21 or p27. This work clarifies our current understanding of the mechanism of action of CDK4/6 inhibitors and has implications for cancer treatment and patient stratification.

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The structure of the human cell cycle

Cited by 8 publications

References 56 publications

Genomic hallmarks and therapeutic implications of G0 cell cycle arrest in cancer

Genomic hallmarks and therapeutic implications of G0 cell cycle arrest in cancer

Cdt1 inhibits CMG helicase in early S phase to separate origin licensing from DNA synthesis

Palbociclib-mediated cell cycle arrest can occur in the absence of the CDK inhibitors p21 and p27

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