5-aza-2'-deoxycytidine activates the p53/p21Waf1/Cip1 pathway to inhibit cell proliferation.
In addition to its demethylating function, 5-aza-2'-deoxycytidine (5-aza-CdR) also plays an important role in inducing cell cycle arrest, differentiation, and cell death. However, the mechanism by which 5-aza-CdR induces antineoplastic activity is not clear. In this study, we found that 5-aza-CdR at limited concentrations (0.01-5 microm) induces inhibition of cell proliferation as well as increased p53/p21(Waf1/Cip1) expression in A549 cells (wild-type p53) but not in H1299 (p53-null) and H719 cells (p53 mutant). The p53-dependent p21(Waf1/Cip1) expression induced by 5-aza-CdR was not seen in A549 cells transfected with the wild-type human papilloma virus type-16 E6 gene that induces p53 degradation. Furthermore, deletion analysis and site-directed mutagenesis of the p21 promoter reveals that 5-aza-CdR induces p21(Waf1/Cip1) expression through two p53 binding sites in the p21 promoter. Finally, 5-aza-CdR-induced p21(Waf1/Cip1) expression was dependent on DNA damage but not on DNA demethylation as demonstrated by comet assay and bisulfite sequencing, respectively. Our data provide useful clues for judging the therapeutic efficacy of 5-aza-CdR in the treatment of human cancer cells.
Zhu
Wei-Guo
WG
Department of Biochemistry and Molecular Biology, University of Health Science Center, Beijing, China.
Hileman
Theresa
T
Ke
Yang
Y
Wang
Peichang
P
Lu
Shaoli
S
Duan
Wenrui
W
Dai
Zunyan
Z
Tong
Tanjun
T
Villalona-Calero
Miguel A
MA
Plass
Christoph
C
Otterson
Gregory A
GA
D000975:Antioxidants / Q000494:pharmacology; D001374:Azacitidine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D001665:Binding Sites; D015153:Blotting, Western; D002454:Cell Differentiation; D002455:Cell Division; D045744:Cell Line, Tumor; D002470:Cell Survival; D020552:Comet Assay; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000378:metabolism*; D004249:DNA Damage; D019175:DNA Methylation; D000077209:Decitabine; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D008156:Luciferases / Q000378:metabolism; D008957:Models, Genetic; D016297:Mutagenesis, Site-Directed; D009856:Oncogene Proteins, Viral / Q000235:genetics; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins; D013447:Sulfites / Q000494:pharmacology; D013997:Time Factors; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
D000975:Antioxidants; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; C068651:E6 protein, Human papillomavirus type 16; D004791:Enzyme Inhibitors; D009856:Oncogene Proteins, Viral; D012097:Repressor Proteins; D013447:Sulfites; D016159:Tumor Suppressor Protein p53; D000077209:Decitabine; D008156:Luciferases; D001374:Azacitidine; C009279:sodium bisulfite