Phenotypic Differentiation without Permanent Cell-Cycle Arrest by Skeletal Myocytes with Deregulated E2F-1

Senescence is the end point of a complex cellular response that proceeds through a set of highly regulated steps. Initially, the permanent cell-cycle arrest that characterizes senescence is a pro-survival response to irreparable DNA damage. The maintenance of this prolonged condition requires the adaptation of the cells to an unfavorable, demanding and stressful microenvironment. This adaptation is orchestrated through a deep epigenetic resetting. A first wave of epigenetic changes builds a dam on irreparable DNA damage and sustains the pro-survival response and the cell-cycle arrest. Later on, a second wave of epigenetic modifications allows the genomic reorganization to sustain the transcription of pro-inflammatory genes. The balanced epigenetic dynamism of senescent cells influences physiological processes, such as differentiation, embryogenesis and aging, while its alteration leads to cancer, neurodegeneration and premature aging. Here we provide an overview of the most relevant histone modifications, which characterize senescence, aging and the activation of a prolonged DNA damage response.

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What Lies in between Telomere and Organismal Ageing: Comparison between Replicative Senescence and Stress-Induced Premature Senescence

E3S Web of Conferences ◽

10.1051/e3sconf/202124503051 ◽

2021 ◽

Vol 245 ◽

pp. 03051

Author(s):

Hanyi Jia

Keyword(s):

Cell Cycle ◽

Dna Damage ◽

Cell Cycle Arrest ◽

Dna Damage Response ◽

Replicative Senescence ◽

Premature Senescence ◽

Cycle Arrest ◽

Damage Response ◽

Permanent Cell ◽

Stress Induced Premature Senescence

A mitotic cell that rests in permanent cell cycle arrest without the ability to divide is considered as a senescent cell. Cellular senescence is essential to limit the function of cells with heavy DNA damages. The lack of senescence is in favour of tumorigenesis, whereas the accumulation of senescent cells in tissues is likely to induce ageing and age-related pathologies on the organismal level. Understanding of cellular senescence is thus critical to both cancer and ageing studies. Senescence, essentially permanent cell cycle arrest, is one of the results of DNA damage response, such as the ataxia telangiectasia mutated and the ataxia telangiectasia and Rad3-related signaling pathways. In other cases, mild DNA damages can usually be repaired after DNA damage response, while the cells with heavy damages on DNA end in apoptosis. The damage to the special structure of telomere, however, prone to result in permanent cell cycle arrest after activation of DNA damage response. In fact, a few previous pieces of research on ageing have largely focused on telomere and considered it a primary contributor to different types of senescence. For instance, its reduction in length after each replication turns on a timer for replicative senescence, and its tandem repeats specific to binding proteins makes it susceptible to DNA damage from oxidative stress, and thus stress-induced premature senescence. In most of the senescent cells, the accumulation of biomarkers is found around the telomere which has either its tail structure disassembled or damage foci exposed on the tandem repeats. In this review, among several types of senescence, I will investigate two of the most common and widely discussed types in eukaryotic cells -replicative senescence and stress-induced premature senescence - in terms of their mechanism, relationship with telomere, and implication to organismal ageing.

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Cellular Senescence and Anti-Cancer Therapy

Current Drug Targets ◽

10.2174/1389450120666181217100833 ◽

2019 ◽

Vol 20 (7) ◽

pp. 705-715 ◽

Cited By ~ 1

Author(s):

Jieqiong You ◽

Rong Dong ◽

Meidan Ying ◽

Qiaojun He ◽

Ji Cao ◽

...

Keyword(s):

Cell Cycle ◽

Tumor Progression ◽

Cell Cycle Arrest ◽

Cancer Progression ◽

Cellular Senescence ◽

Cancer Disease ◽

Cycle Arrest ◽

Permanent Cell ◽

Cellular Stresses

Background: Cellular senescence is generally understood as a permanent cell cycle arrest stemming from different causes. The mechanism of cellular senescence-induced cell cycle arrest is complex, involving interactions between telomere shortening, inflammations and cellular stresses. In recent years, a growing number of studies have revealed that cellular senescence could mediate the cancer progression of neighboring cells, but this idea is controversial and contradictory evidence argues that cellular senescence also contributes to tumor suppression. Objective: Given that the complicated role of senescence in various physiological and pathological scenarios, we try to clarify the precise contribution role of cellular senescence to tumor progression. Methods: Search for the information in a large array of relevant articles to support our opinion. Results: We discuss the relatively widespread occurrence of cellular senescence in cancer treatment and identify the positive and negative side of senescence contributed to tumor progression. Conclusion: We argue that the availability of pro-senescence therapy could represent as a promising regimen for managing cancer disease, particularly with regard to the poor clinical outcome obtained with other anticancer therapies.

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Yeast replicative aging leads to permanent cell cycle arrest in G1 effectuated by the start repressor Whi5

10.1101/353664 ◽

2018 ◽

Cited By ~ 1

Author(s):

Jing Yang ◽

Ziwei Wang ◽

Xili Liu ◽

Hao Li ◽

Qi Ouyang

Keyword(s):

Cell Cycle ◽

Cell Cycle Arrest ◽

Microfluidic Devices ◽

Replicative Aging ◽

Cycle Arrest ◽

Permanent Cell ◽

Response To Stress ◽

Stress Signals ◽

Mother Cells ◽

Major Mediator

AbstractYeast replicative aging has been a canonical model for aging research. Since replicative aging eventually leads to permanent cell cycle arrest, a fundamental question is how cells sense the signals from aging and communicate that to the cell cycle control machineries. Using microfluidic devices to track individual mother cells labeled by two different cell cycle markers Whi5-tdTomato and Myo1-EGFP, we measured the length of different cell cycle phases as a function of age and the distribution of cell death in different cell cycle phases. We found that the majority of the cells died in the G1 phase, and their G1 cell cycle length increased drastically in the last few cell divisions. This increase of G1 length correlates with the increase of the nuclear concentration of Whi5, which is a major transcriptional suppressor of the cell cycle start check point. Interestingly, this correlation is apparent only above a threshold concentration of Whi5. We show that in response to external stress, Whi5 concentration increases and cell growth slows down in a Whi5 dependent manner, and that Whi5 deletion significantly extends the lifespan. Together these data suggest the existence of a programmed control to arrest cell cycle in G1 in response to stress signals due to aging, and that Whi5 is a major mediator of this process. Our findings may have important implications in understanding senescence and cancer in mammalian cells, which have a parallel G1/S control system with Rb (a well known tumor suppressor) as the analog of Whi5.Significance statementIn this work, we used microfluidic devices to track individual mother cells labeled by two cell cycle markers Whi5-tdTomato and Myo1-EGFP. We found that aging leads to significant lengthening of G1 phase in old cells and the eventual permanent cell cycle arrest in G1, and Whi5 plays an important role in implementing such a program. We show that oxidative stress can lead to the increase of Whi5 expression and the slow-down of cell division. Furthermore, Whi5 deletion significantly extends the lifespan. The result suggest the existence of a programmed control to arrest cell cycle in G1 in response to stress signals due to aging, and that Whi5 is a major mediator of this process.

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Effects of bioactive compounds on senescence and components of senescence associated secretory phenotypes in vitro

Food & Function ◽

10.1039/c7fo00161d ◽

2017 ◽

Vol 8 (7) ◽

pp. 2394-2418 ◽

Cited By ~ 30

Author(s):

Janubová Mária ◽

Žitňanová Ingrid

Keyword(s):

Cell Cycle ◽

Cell Cycle Arrest ◽

Bioactive Compounds ◽

Cell Morphology ◽

Cycle Arrest ◽

Permanent Cell

Senescence is a permanent cell cycle arrest that is accompanied by changes in cell morphology and physiology occurringin vitroandin vivo.

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