title: Inhibition of NAD(P)H:quinone oxidoreductase 1 activity and induction of p53 degradation by the natural phenolic compound curcumin.
abstract: NAD(P)H:quinone oxidoreductase 1 (NQO1) regulates the stability of the tumor suppressor WT p53. NQO1 binds and stabilizes WT p53, whereas NQO1 inhibitors including dicoumarol and various other coumarins and flavones induce ubiquitin-independent proteasomal p53 degradation and thus inhibit p53-induced apoptosis. Here, we show that curcumin, a natural phenolic compound found in the spice turmeric, induced ubiquitin-independent degradation of WT p53 and inhibited p53-induced apoptosis in normal thymocytes and myeloid leukemic cells. Like dicoumarol, curcumin inhibited the activity of recombinant NQO1 in vitro, inhibited the activity of endogenous cellular NQO1 in vivo, and dissociated NQO1-WT p53 complexes. Neither dicoumarol nor curcumin dissociated the complexes of NQO1 and the human cancer hot-spot p53 R273H mutant and therefore did not induce degradation of this mutant. NQO1 knockdown by small-interfering RNA induced degradation of both WT p53 and the p53 R273H mutant. The results indicate that curcumin induces p53 degradation and inhibits p53-induced apoptosis by an NQO1-dependent pathway.
authors.affiliation: Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Peter
authors.initials: P
authors.lastname: Tsvetkov
authors.forename: Gad
authors.initials: G
authors.lastname: Asher
authors.forename: Veronica
authors.initials: V
authors.lastname: Reiss
authors.forename: Yosef
authors.initials: Y
authors.lastname: Shaul
authors.forename: Leo
authors.initials: L
authors.lastname: Sachs
authors.forename: Joseph
authors.initials: J
authors.lastname: Lotem
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D003474:Curcumin / Q000494:pharmacology*; D006801:Humans; D051379:Mice; D020125:Mutation, Missense / Q000235:genetics; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000037:antagonists & inhibitors* / Q000378:metabolism; D009369:Neoplasms / Q000235:genetics; D013950:Thymus Gland / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D025801:Ubiquitin / Q000378:metabolism
chemical_list: D016159:Tumor Suppressor Protein p53; D025801:Ubiquitin; D016660:NAD(P)H Dehydrogenase (Quinone); C447479:NQO1 protein, human; D003474:Curcumin