title: Histone deacetylase inhibitor Trichostatin A induces global and gene-specific DNA demethylation in human cancer cell lines.
abstract: DNA methylation and chromatin structure are two modes of epigenetic control of genome function. Although it is now well established that chromatin silencing could lead to DNA methylation, the relation between chromatin activation and DNA demethylation is unclear. It was generally believed that expression of methylated genes could only be restored by demethylating agents, such as 5-aza-deoxycytidine (5-azaCdR), and that inhibition of histone deacetylation by Trichostatin A (TSA) only activates transcription of unmethylated genes. In this report, we show that increase of histone acetylation by TSA was associated with a significant decrease in global methylation. This global demethylation occurs even when DNA replication is blocked by hydroxyurea, supporting a replication-independent-mechanism of demethylation. TSA also induces histone acetylation, demethylation and expression of the methylated E-CADHERIN and RARbeta2 genes. However, the genome-wide demethylation induced by TSA does not affect all methylated tumor suppressor genes equally suggesting that induction of acetylation and demethylation by TSA shows some gene selectivity. Taken together, our data provide evidence for a reversible crosstalk between histone acetylation and DNA demethylation, which has significant implications on the use of HDAC inhibitors as therapeutic agents.
authors.affiliation: Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada.
authors.forename: Jing-Ni
authors.initials: JN
authors.lastname: Ou
authors.forename: Jérôme
authors.initials: J
authors.lastname: Torrisani
authors.forename: Alexander
authors.initials: A
authors.lastname: Unterberger
authors.forename: Nadine
authors.initials: N
authors.lastname: Provençal
authors.forename: Keisuke
authors.initials: K
authors.lastname: Shikimi
authors.forename: Mohsen
authors.initials: M
authors.lastname: Karimi
authors.forename: Tomas J
authors.initials: TJ
authors.lastname: Ekström
authors.forename: Moshe
authors.initials: M
authors.lastname: Szyf
mesh_terms: D024506:5' Flanking Region / Q000187:drug effects; D000107:Acetylation; D001943:Breast Neoplasms / Q000473:pathology; D015820:Cadherins / Q000235:genetics* / Q000378:metabolism; D019175:DNA Methylation / Q000187:drug effects*; D004261:DNA Replication; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D056572:Histone Deacetylase Inhibitors; D006655:Histone Deacetylases / Q000378:metabolism; D006657:Histones / Q000378:metabolism; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology*; D020071:Interspersed Repetitive Sequences / Q000187:drug effects* / Q000502:physiology; D024363:Transcription Initiation Site / Q000187:drug effects; D014407:Tumor Cells, Cultured; D001749:Urinary Bladder Neoplasms / Q000473:pathology
chemical_list: D015820:Cadherins; D004791:Enzyme Inhibitors; D056572:Histone Deacetylase Inhibitors; D006657:Histones; D006877:Hydroxamic Acids; C012589:trichostatin A; D006655:Histone Deacetylases