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Background Both p16~(INK4) and p21~(Waf1) are tumor suppressors with similar biological functions in the regulation ofcellular senescence.Previous reports showed that p16~(INK4) could be activated by p21~(Waf1) through transcriptional factorSpl in HeLa cells.This study was undertaken to determine the effects of p16~(INK4) on the expression and functions ofp21~(Waf1).Methods Human diploid fibroblast 2BS cells were stably transfected with sense (2BS/p16~(INK4)),antisense p16~(INK4)(2BS/asp16~(INK4)) 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/p16~(INK4) cells exhibited cell cycle arrest in both G1 and G2/M phases.Endogenous p21~(Waf1) protein levelsincreased twofold in the 2BS/p16~(INK4) cells,but not decreased in the 2BS/asp16~(INK4) cells,p21~(Waf1) mRNA levels were notaffected in neither 2BS/p16~(INK4) nor 2BS/asp16~(INK4) cells.Conclusion p16~(INK4) may play an important role in the regulation of cellular senescence by modulating the p21~(Waf1)protein level via the posttranscriptional mechanism.Chin Med J 2007;120(5):405-409
Background Both p16 ~ (INK4) and p21 ~ (Waf1) are tumor suppressors with similar biological functions in the regulation ofcellular senescence. Previously reported showed that p16 ~ (INK4) could be activated by p21 ~ (Waf1) through transcriptional factor Sp1 in HeLa cells . This study was undertaken to determine the effects of p16 ~ (INK4) on the expression and functions of p21 ~ (Waf1). Methods Human diploid fibroblast 2BS cells were stably transfected with sense (2BS / p16 ~ (INK4)), antisense p16 ~ (INK4) or empty vector (2BS / neo) .Then they were assayed by reverse-transcription polymerase chain reaction (RT-PCR), fluorescence activated cell sorting (FACS) and Western blot. Results 2BS / p16 ~ (INK4) cells showed cell cycle arrest in both G1 and G2 / M phases. Endogenous p21 ~ (Waf1) protein levels increased in twofold in the 2BS / p16 ~ (INK4) cells, but not decreased in the 2BS / asp16 ~ INK4) cells, p21 ~ (Waf1) mRNA levels were not affected in neither 2BS / p16 ~ (INK4) nor 2BS / asp16 ~ (INK4) cells.Conclusion p16 ~ may play an important role in the regulation of cellular senescence by modulating the p21 ~ (Waf1) protein level via the posttranscriptional mechanism. Chin Med J 2007; 120 (5): 405-409