Cellular Senescence

Abstract

This chapter discusses cellular senescence, which is a new branch of cell biology. The studies of senescence have a more general significance beyond their immediate biological impact. Senescence in organisms has long been regarded as a manifestation of a system tending toward equilibrium, disordering until it dies. Cellular senescence is a wide-spread phenomenon in cell populations and cell clones. This is true whether it turns out to have any direct or causal relation to whole-organism senescence. It raises many fundamental questions about the expression of genetic programs, the manner in which intracellular programs manifest themselves in population phenotypes, and the ways in which such programs may be overridden by random perturbations. At present, there is no real understanding of senescent phenomena, either at the cellular or the population level. In any case, it should be clear that the field of cellular senescence impacts in an important way on all other aspects of cell biology and on the role played by cell biology in the understanding of developmental and physiological processes in multicellular organisms.