title: DNA methylation-independent loss of RARA gene expression in acute myeloid leukemia.
abstract: The retinoic acid receptor (RAR) alpha gene (RARA) encodes 2 major isoforms and mediates positive effects of all-trans retinoic acid (ATRA) on myelomonocytic differentiation. Expression of the ATRA-inducible (RARalpha2) isoform increases with myelomonocytic differentiation and appears to be down-regulated in many acute myeloid leukemia (AML) cell lines. Here, we demonstrate that relative to normal myeloid stem/progenitor cells, RARalpha2 expression is dramatically reduced in primary AML blasts. Expression of the RARalpha1 isoform is also significantly reduced in primary AML cells, but not in AML cell lines. Although the promoters directing expression of RARalpha1 and RARalpha2 are respectively unmethylated and methylated in AML cell lines, these regulatory regions are unmethylated in all the AML patient cell samples analyzed. Moreover, in primary AML cells, histones associated with the RARalpha2 promoter possessed diminished levels of H3 acetylation and lysine 4 methylation. These results underscore the complexities of the mechanisms responsible for deregulation of gene expression in AML and support the notion that diminished RARA expression contributes to leukemogenesis.
authors.affiliation: Section of Haemato-Oncology, Institute of Cancer Research, Sutton, United Kingdom.
authors.forename: Annegret
authors.initials: A
authors.lastname: Glasow
authors.forename: Angela
authors.initials: A
authors.lastname: Barrett
authors.forename: Kevin
authors.initials: K
authors.lastname: Petrie
authors.forename: Rajeev
authors.initials: R
authors.lastname: Gupta
authors.forename: Manuel
authors.initials: M
authors.lastname: Boix-Chornet
authors.forename: Da-Cheng
authors.initials: DC
authors.lastname: Zhou
authors.forename: David
authors.initials: D
authors.lastname: Grimwade
authors.forename: Robert
authors.initials: R
authors.lastname: Gallagher
authors.forename: Marieke
authors.initials: M
authors.lastname: von Lindern
authors.forename: Samuel
authors.initials: S
authors.lastname: Waxman
authors.forename: Tariq
authors.initials: T
authors.lastname: Enver
authors.forename: Guido
authors.initials: G
authors.lastname: Hildebrandt
authors.forename: Arthur
authors.initials: A
authors.lastname: Zelent
mesh_terms: D001854:Bone Marrow Cells / Q000187:drug effects / Q000473:pathology; D002454:Cell Differentiation / Q000187:drug effects; D019175:DNA Methylation; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000235:genetics* / Q000473:pathology; D011401:Promoter Regions, Genetic; D018168:Receptors, Retinoic Acid / Q000235:genetics*; D000072482:Retinoic Acid Receptor alpha; D014212:Tretinoin / Q000494:pharmacology
chemical_list: C000607071:RARA protein, human; D018168:Receptors, Retinoic Acid; D000072482:Retinoic Acid Receptor alpha; D014212:Tretinoin