FIGURE 1.

Stressors inducing cellular senescence and hallmarkers of senescent cells. Cellular senescence can be induced by multiple internal and external stressors, such as telomere attrition, DNA damage, oxidative stress, oncogene activation, ultraviolet (UV) radiation, chronic inflammation, and abnormal mechanical stress. These senescent cells (SnCs) exhibit a variety of typical hallmarkers, including irreversible growth arrest, altered cell size and morphology, macromolecular damage, increased expression of p21^CIP1 and p16^INK4A, enhanced senescence-associated-β-galactosidase (SA-β-Gal) activity, senescence-associated heterochromatic foci (SAHFs) formation, senescence-associated secretory phenotype (SASP) and extracellular vesicles (EVs) associated with senescence.