RRC ID 34755
Author Fan J, Kodama E, Koh Y, Nakao M, Matsuoka M.
Title Halogenated thymidine analogues restore the expression of silenced genes without demethylation.
Journal Cancer Res.
Abstract Transcriptional silencing of tumor suppressor genes by aberrant DNA methylation is a characteristic frequently observed in cancer cells. Therefore, reversing this process is a therapeutic target against cancer. In this study, we established a screening system for silencing inhibitors with cell lines transfected by a retroviral vector containing a luciferase gene. More than 100 nucleosides were tested for antisilencing activity with a selected clone in which the silenced expression of luciferase could be recovered by 5-aza-2'-deoxycytidine. A group of halogenated thymidine analogues was found to reactivate transcription of not only the reporter retrovirus vector but also endogenous glutathione-S-transferase 1 gene, without influence to DNA hypermethylation. Gel mobility shift assay showed that 5-bromo-2'-deoxyuridine (BrdUrd) or 5-iodo-2'-deoxyuridine incorporation did not affect the binding of the methyl-CpG binding protein motif to methylated DNA. Finally, in the retroviral promoter, BrdUrd treatment increased the acetylated histone H3 level and decreased methylation of histone H3 Lys9 in accordance with recovered transcription. This study shows that halogenated thymidines have an antisilencing effect without changing DNA methylation status by interfering with step(s) between DNA methylation and histone acetylation.
Volume 65(15)
Pages 6927-33
Published 2005-8-1
DOI 10.1158/0008-5472.CAN-04-3495
PII 65/15/6927
PMID 16061677
MeSH Antimetabolites, Antineoplastic / pharmacology Base Sequence Bromodeoxyuridine / pharmacology Cell Line, Tumor CpG Islands / drug effects CpG Islands / genetics DNA / drug effects DNA / genetics DNA / metabolism DNA Methylation / drug effects Drug Screening Assays, Antitumor / methods Gene Expression Regulation, Neoplastic / drug effects Gene Silencing / drug effects* Genetic Vectors / genetics Histones / drug effects Histones / genetics Humans Hydrocarbons, Halogenated / pharmacology K562 Cells Molecular Sequence Data Moloney murine leukemia virus / drug effects Moloney murine leukemia virus / genetics Thymidine / analogs & derivatives* Thymidine / pharmacology*
IF 8.378
Times Cited 9
DNA material pCMV-VSV-G (RDB04392)