title: Continuous zebularine treatment effectively sustains demethylation in human bladder cancer cells.
abstract: During tumorigenesis, tumor suppressor and cancer-related genes are commonly silenced by aberrant DNA methylation in their promoter regions. Recently, we reported that zebularine [1-(beta-D-ribofuranosyl)-1,2-dihydropyrimidin-2-one] acts as an inhibitor of DNA methylation and exhibits chemical stability and minimal cytotoxicity both in vitro and in vivo. Here we show that continuous application of zebularine to T24 cells induces and maintains p16 gene expression and sustains demethylation of the 5' region for over 40 days, preventing remethylation. In addition, continuous zebularine treatment effectively and globally demethylated various hypermethylated regions, especially CpG-poor regions. The drug caused a complete depletion of extractable DNA methyltransferase 1 (DNMT1) and partial depletion of DNMT3a and DNMT3b3. Last, sequential treatment with 5-aza-2'-deoxycytidine followed by zebularine hindered the remethylation of the p16 5' region and gene resilencing, suggesting the possible combination use of both drugs as a potential anticancer regimen.
authors.affiliation: Department of Urology, USC/Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California 90089-9181, USA.
authors.forename: Jonathan C
authors.initials: JC
authors.lastname: Cheng
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Weisenberger
authors.forename: Felicidad A
authors.initials: FA
authors.lastname: Gonzales
authors.forename: Gangning
authors.initials: G
authors.lastname: Liang
authors.forename: Guo-Liang
authors.initials: GL
authors.lastname: Xu
authors.forename: Ye-Guang
authors.initials: YG
authors.lastname: Hu
authors.forename: Victor E
authors.initials: VE
authors.lastname: Marquez
authors.forename: Peter A
authors.initials: PA
authors.lastname: Jones
mesh_terms: D001374:Azacitidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D003562:Cytidine / Q000031:analogs & derivatives; D004247:DNA / Q000187:drug effects*; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000037:antagonists & inhibitors / Q000378:metabolism; D019175:DNA Methylation / Q000187:drug effects; D000077209:Decitabine; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D020868:Gene Silencing / Q000187:drug effects; D019942:Genes, p16 / Q000187:drug effects*; D006801:Humans; D011741:Pyrimidine Nucleosides / Q000494:pharmacology*; D001749:Urinary Bladder Neoplasms / Q000188:drug therapy*
chemical_list: D004791:Enzyme Inhibitors; D011741:Pyrimidine Nucleosides; D003562:Cytidine; D000077209:Decitabine; C009131:pyrimidin-2-one beta-ribofuranoside; D004247:DNA; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; C000619380:DNMT1 protein, human; D001374:Azacitidine