Blue period - features of senescence 30 years after beta-galactosidase

Cellular senescence is a multi-phenotypic stress or damage response characterized by a stable cell cycle arrest and the secretion of a myriad of biologically active molecules, commonly known as the senescence-associated secretory phenotype (SASP). Thirty years ago, the identification of activated beta-galactosidase during senescence led to one of the first characterizations of senescent cell accumulation during biological aging. Since then, interventions that either selectively eliminate senescent cells or suppress the SASP have demonstrated that they are a major etiological agent for several degenerative pathologies associated with aging. As interest in the development of targeted therapeutics for senescence has grown, so too has the interest in the study of these cells. This has resulted in discovery of new features and phenotypes that often associate with senescence. Here, we review several of these key features of senescence, highlighting the strengths and caveats associated with each.