The role of senescent cells in ageing

Cellular senescence has recently been shown to have roles in complex biological processes other than protection against cancer, and to represent a series of progressive and diverse cellular states after initial growth arrest; better understanding of mechanisms underlying its progression and of acute and chronic senescent cells may lead to new therapeutic strategies for age-related pathologies. Relatively little is known about the basic biology of senescent cells, particularly in vivo, but mounting evidence that cell senescence plays a role in ageing and age-related disease has stimulated interest in the topic. Here Jan van Deursen reviews recent work on the role of senescent cells in ageing. New findings suggest that senescence is not a static cellular endpoint. Rather, it is a dynamic series of cellular states linked to tissue repair and cancer as well as to ageing. van Deursen goes on to discuss how the new information that is emerging could be exploited to clear detrimental senescent cell populations selectively to improve healthy lifespan. Cellular senescence has historically been viewed as an irreversible cell-cycle arrest mechanism that acts to protect against cancer, but recent discoveries have extended its known role to complex biological processes such as development, tissue repair, ageing and age-related disorders. New insights indicate that, unlike a static endpoint, senescence represents a series of progressive and phenotypically diverse cellular states acquired after the initial growth arrest. A deeper understanding of the molecular mechanisms underlying the multi-step progression of senescence and the development and function of acute versus chronic senescent cells may lead to new therapeutic strategies for age-related pathologies and extend healthy lifespan.