Senescent Cells

Cellular aging is a complex process that results from changes and factors acting at the cellular level, as well as at the level of tissues and the organism as a whole (Lopez-Otin et al. 2013). Cell aging can be characterized as a process characterized by an irreversible form of proliferation arrest. It is considered that cell senescence, together with programmed cell death, represents a protective mechanism involved in the maintenance of tissue homeostasis. Cell senescence has long been viewed as a protective mechanism against neoplasia. However, this view is now changing as it has been found that senescent cells stimulate the development and progression of cancer by various mechanisms. For example, tumor cells themselves may undergo a transient reversible stage of senescence which is associated with, for example, increased resistance to anticancer therapy. Aging may also affect nontumor cells in the tumor microenvironment, such as fibroblasts or endothelial cells, which then act to stimulate the tumor process (Hanahan 2022). The nervous system influences aging processes at both the cellular and systemic level (Kim and Choe 2019).