The role of p16 methylation in the aging of human fetal lung diploid fibroblasts / 中华老年医学杂志

ABSTRACT

Objective　The relationship between DNA methylation and the overexpression of cell cycle negative regulator p16MTS1/INK4a in senescent cells was studied. 　Methods　PCR amplification of p16 exon I following digestion with Sma I , a methylation sensitive DNA endonuclease, was adapted to determine the methylation status at specific site. 　Results　 T-he increased expression of p16 in the aging process of human fetal lung diploid fibroblasts (2BS) was observed. In middle-aged and old cells, the p16 level was about 3 folds and 10 folds respectively as that in young cells. The methylation level of the Sma I site in p16 exon I tended to decline with aging, being about 64% and 41% in young and middle-aged cells respectively, but still maintain relatively as high as about 24% in senescent cells. 　Conclusions　 The overexpression of p16 in senescent human fibroblasts might be related to the alteration of methylation level of exon I, its mechanisms need to be defined further.