Cellular senescence

Abstract

The ageing of cells, cellular senescence, is an event that is encountered in all normal cells. Cells grown in vitro have a limited life span and do not grow well after a certain number of divisions. They cease to divide and eventually die. In accordance with this, the life expectancy of an established cell culture depends on the age of the donor. Cells that have undergone immortalization via a crisis period of transformation by chemicals or viruses, as well as malignant cell lines in general, have an ability to divide indefinitely. A distinct form of cell death, apoptosis or programmed cell death, is encountered in many physiological situations like in keratinocyte differentiation.