REPLICATIVE SENESCENCE - IMPLICATIONS FOR IN-VIVO AGING AND TUMOR SUPPRESSION

Normal cells have limited proliferative potential in culture, a fact t hat has been the basis of their use as a model for replicative senesce nce for many years. Recent molecular analyses have identified numerous changes in gene expression that occur as cells become senescent, and the results indicate that multiple levels of control contribute to the irreversible growth arrest. These include repression of growth stimul atory genes, overexpression of growth inhibitory genes, and interferen ce with downstream pathways. Studies with cell types other than fibrob lasts will better define the role of cell senescence in the aging proc ess and in tumorigenesis.