title: Preclinical evaluation of antineoplastic activity of inhibitors of DNA methylation (5-aza-2'-deoxycytidine) and histone deacetylation (trichostatin A, depsipeptide) in combination against myeloid leukemic cells.
abstract: During the development of leukemia, genes that suppress growth and induce differentiation can be silenced by aberrant DNA methylation and by changes in chromatin structure that involve histone deacetylation. It has been reported that a positive interaction between DNA methylation and histone deacetylation takes place to inhibit transcription. Based on this observation, our working hypothesis was that a combination of inhibitors of these processes should produce an enhancement of their antineoplastic activity on leukemic cells. The cytosine nucleoside analog, 5-aza-2'-deoxycytidine (5AZA), is a potent inhibitor of DNA methylation, which can activate tumor suppressor genes in leukemic cells that have been silenced by aberrant methylation. In clinical trials, 5AZA was demonstrated to be an active antileukemic agent. Histone deacetylase inhibitors (HDI) can also activate gene expression in leukemic cell lines by producing changes in chromatin configuration, and show antineoplastic activity in preclinical studies. In this report, we investigated the in vitro antineoplastic activity of 5AZA, alone and in combination with the HDI, trichostatin A (TSA) and depsipeptide (FR901228, depsi), on the human myeloid leukemic cell lines, HL-60 and KG1a. The results showed that the combination of 5AZA with TSA or depsi produced a greater inhibition of growth and DNA synthesis and a greater loss of clonogenicity than either agent alone. These results suggest that 5AZA used in combination with HDI may be an interesting chemotherapeutic regimen to investigate in patients with acute myeloid leukemia that is resistant to conventional chemotherapy.
authors.affiliation: Centre de Recherche Pédiatrique, Hôpital Sainte-Justine, 3175 Côte Ste-Catherine, Montréal, Quebec, Canada H3T 1C5.
authors.forename: Sepideh
authors.initials: S
authors.lastname: Shaker
authors.forename: Mark
authors.initials: M
authors.lastname: Bernstein
authors.forename: Louise F
authors.initials: LF
authors.lastname: Momparler
authors.forename: Richard L
authors.initials: RL
authors.lastname: Momparler
mesh_terms: D000107:Acetylation / Q000187:drug effects; D000208:Acute Disease; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology*; D001374:Azacitidine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects; D019175:DNA Methylation / Q000187:drug effects*; D004261:DNA Replication / Q000187:drug effects; D004273:DNA, Neoplasm / Q000378:metabolism; D000077209:Decitabine; D047630:Depsipeptides; D004354:Drug Screening Assays, Antitumor; D004357:Drug Synergism; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D018922:HL-60 Cells / Q000187:drug effects; D056572:Histone Deacetylase Inhibitors; D006657:Histones / Q000378:metabolism*; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology*; D007951:Leukemia, Myeloid / Q000473:pathology*; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors*; D010456:Peptides, Cyclic; D011499:Protein Processing, Post-Translational / Q000187:drug effects*; D014407:Tumor Cells, Cultured / Q000187:drug effects; D014410:Tumor Stem Cell Assay
chemical_list: D000900:Anti-Bacterial Agents; D000903:Antibiotics, Antineoplastic; D004273:DNA, Neoplasm; D047630:Depsipeptides; D004791:Enzyme Inhibitors; D056572:Histone Deacetylase Inhibitors; D006657:Histones; D006877:Hydroxamic Acids; D009363:Neoplasm Proteins; D010456:Peptides, Cyclic; C012589:trichostatin A; D000077209:Decitabine; C087123:romidepsin; D001374:Azacitidine