title: Histone deacetylase inhibitors induce remission in transgenic models of therapy-resistant acute promyelocytic leukemia.
abstract: Acute promyelocytic leukemia (APL) is associated with chromosomal translocations, invariably involving the retinoic acid receptor alpha (RAR alpha) gene fused to one of several distinct loci, including the PML or PLZF genes, involved in t(15;17) or t(11;17), respectively. Patients with t(15;17) APL respond well to retinoic acid (RA) and other treatments, whereas those with t(11;17) APL do not. The PML-RAR alpha and PLZF-RAR alpha fusion oncoproteins function as aberrant transcriptional repressors, in part by recruiting nuclear receptor-transcriptional corepressors and histone deacetylases (HDACs). Transgenic mice harboring the RAR alpha fusion genes develop forms of leukemia that faithfully recapitulate both the clinical features and the response to RA observed in humans with the corresponding translocations. Here, we investigated the effects of HDAC inhibitors (HDACIs) in vitro and in these animal models. In cells from PLZF-RAR alpha/RAR alpha-PLZF transgenic mice and cells harboring t(15;17), HDACIs induced apoptosis and dramatic growth inhibition, effects that could be potentiated by RA. HDACIs also increased RA-induced differentiation. HDACIs, but not RA, induced accumulation of acetylated histones. Using microarray analysis, we identified genes induced by RA, HDACIs, or both together. In combination with RA, all HDACIs tested overcame the transcriptional repression exerted by the RAR alpha fusion oncoproteins. In vivo, HDACIs induced accumulation of acetylated histones in target organs. Strikingly, this combination of agents induced leukemia remission and prolonged survival, without apparent toxic side effects.
authors.affiliation: Molecular Biology Program and Department of Pathology, Memorial Sloan-Kettering Cancer Center, Sloan-Kettering Division, Graduate School of Medical Sciences, Cornell University, New York, New York 10021, USA.
authors.forename: L Z
authors.initials: LZ
authors.lastname: He
authors.forename: T
authors.initials: T
authors.lastname: Tolentino
authors.forename: P
authors.initials: P
authors.lastname: Grayson
authors.forename: S
authors.initials: S
authors.lastname: Zhong
authors.forename: R P
authors.initials: RP
authors.lastname: Warrell
authors.forename: R A
authors.initials: RA
authors.lastname: Rifkind
authors.forename: P A
authors.initials: PA
authors.lastname: Marks
authors.forename: V M
authors.initials: VM
authors.lastname: Richon
authors.forename: P P
authors.initials: PP
authors.lastname: Pandolfi
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis; D015152:Blotting, Northern; D015153:Blotting, Western; D002453:Cell Cycle; D002454:Cell Differentiation; D002455:Cell Division; D018076:DNA, Complementary / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D056572:Histone Deacetylase Inhibitors; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D020287:In Situ Nick-End Labeling; D015473:Leukemia, Promyelocytic, Acute / Q000188:drug therapy* / Q000235:genetics*; D051379:Mice; D008822:Mice, Transgenic; D008856:Microscopy, Fluorescence; D008956:Models, Chemical; D020411:Oligonucleotide Array Sequence Analysis; D010654:Phenylbutyrates / Q000494:pharmacology; D011485:Protein Binding; D018168:Receptors, Retinoic Acid / Q000235:genetics; D012074:Remission Induction; D000072482:Retinoic Acid Receptor alpha; D013997:Time Factors; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured; D015854:Up-Regulation; D000077337:Vorinostat
chemical_list: D000970:Antineoplastic Agents; D018076:DNA, Complementary; D004791:Enzyme Inhibitors; D056572:Histone Deacetylase Inhibitors; D006877:Hydroxamic Acids; D010654:Phenylbutyrates; C000607071:RARA protein, human; C000607072:Rara protein, mouse; D018168:Receptors, Retinoic Acid; D000072482:Retinoic Acid Receptor alpha; C012589:trichostatin A; D000077337:Vorinostat