Aging 2 Animals 2 BHK cell line 2 CDK inhibitor 2 Carcinogenesis 2 Cell Aging 2 Cell Cycle Checkpoints 2 Cellular senescence 2 Cyclin-Dependent Kinase Inhibitor p19 2 DNA Damage 2 DNA damage 2 Gene Expression Regulation 2 HEK293 cell line 2 Heterochromatin 2 Mice 2 aged 2 animal cell 2 animal tissue 2 article 2 beta galactosidase 2 beta-Galactosidase 2 cell aging 2 cell cycle arrest 2 cell nucleus 2 cellular distribution 2 chromatin condensation 2 controlled study 2 cyclin dependent kinase inhibitor 2D 2 heterochromatin 2 human 2