Posttranscriptionalinductionofp21Waflmediatedbyectopicp16INK4inhumandiploidfibroblast

<正> Background Both p16INK4 and p21Waf1 are tumor suppressors with similar biological functions in the regulation ofcellular senescence.Previous reports showed that p16INK4 could be activated by p21Waf1 through transcriptional factorSpl in HeLa cells.This study was undertaken to determine the effects of p16INK4 on the expression and functions ofp21Waf1.Methods Human diploid fibroblast 2BS cells were stably transfected with sense (2BS/p16INK4),antisense p16INK4(2BS/asp16INK4) or empty vector （2BS/neo）.Then they were assayed by reverse-transcription polymerase chainreaction （RT-PCR）,fluorescence activated cell sorting （FACS） and Western blot.Results 2BS/p16INK4 cells exhibited cell cycle arrest in both G1 and G2/M phases.Endogenous p21Waf1 protein levelsincreased twofold in the 2BS/p16INK4 cells,but not decreased in the 2BS/asp16INK4 cells,p21Waf1 mRNA levels were notaffected in neither 2BS/p16INK4 nor 2BS/asp16INK4 cells.Conclusion p16INK4 may play an important role in the regulation of cellular senescence by modulating the p21Waf1protein level via the posttranscriptional mechanism.Chin Med J 2007;120（5）:405-409