title: p53-, SIRT1-, and PARP-1-independent downregulation of p21WAF1 expression in nicotinamide-treated cells.
abstract: Nicotinamide at mM concentration is a potent inhibitor of certain key molecules involved in cell survival, such as SIRT1 and PARP-1, and affects cell survival in various conditions in vivo and in vitro. However, the effect of an acute treatment of nicotinamide on gene expression has rarely been closely examined. In our study, the treatment of 10mM nicotinamide downregulated p21WAF1 expression in various human cells including p53-negative or SIRT1-knockdown cells indicating gene regulation not mediated by p53 or SIRT1. Meanwhile, in the nicotinamide-treated cells, Sp1 activity and protein level was substantially reduced due to increased proteasome-mediated degradation. Our results indicate that nicotinamide treatment attenuates p21WAF1 expression through Sp1 downregulation, and suggest a possible involvement of nicotinamide metabolism in cellular gene expression.
authors.affiliation: Department of Life Science, University of Seoul, Dongdaemungu, Jeonnongdong 90, Seoul 130-743, Republic of Korea.
authors.forename: Hyung Il
authors.initials: HI
authors.lastname: Lee
authors.forename: So-Young
authors.initials: SY
authors.lastname: Jang
authors.forename: Hyun Tae
authors.initials: HT
authors.lastname: Kang
authors.forename: Eun Seong
authors.initials: ES
authors.lastname: Hwang
mesh_terms: D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism*; D015536:Down-Regulation / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D009536:Niacinamide / Q000008:administration & dosage*; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D056564:Sirtuin 1; D037761:Sirtuins / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
chemical_list: C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016159:Tumor Suppressor Protein p53; D009536:Niacinamide; C499320:PARP1 protein, human; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; C447939:SIRT1 protein, human; D056564:Sirtuin 1; D037761:Sirtuins