title: Comparative analysis of genes regulated by PML/RAR alpha and PLZF/RAR alpha in response to retinoic acid using oligonucleotide arrays.
abstract: Acute promyelocytic leukemia (APL) is associated with chromosomal translocations involving retinoic acid receptor alpha (RAR alpha) and its fusion partners including promyelocytic leukemia (PML) and promyelocytic leukemia zinc finger (PLZF). Using oligonucleotide arrays, we examined changes in global gene expression mediated by the ectopic expression of either PML/RAR alpha (retinoid-sensitive) or PLZF/RAR alpha (retinoid-resistant) in U937 cells. Of more than 5000 genes analyzed, 16 genes were commonly up-regulated, and 57 genes were down-regulated by both fusion proteins suggesting their role in the APL phenotype. In our APL model, for example, TNFAIP2, TNFR2, ELF4, RAR gamma, and HoxA1 were down-regulated by both fusion proteins in the absence of retinoic acid (RA). RA strongly up-regulated these genes in PML/RAR alpha, but not in PLZF/RAR alpha expressing U937 cells. Expression studies in NB4, retinoid-resistant NB4-R2, normal human CD34+ cells, and APL patient samples strongly suggest their role in the regulation of granulocytic differentiation. Furthermore, combined treatment with tumor necrosis factor alpha (TNF alpha) and RA synergistically enhanced granulocytic differentiation in NB4 cells but not in NB4-R2 cells. Our data indicate that APL pathogenesis and retinoid-induced granulocytic differentiation of APL cells involve genes in the cell death pathway, and that cooperation between the RA and TNFalpha signaling pathways exists. Targeting both the retinoid-dependent differentiation and the cell death pathways may improve leukemic therapy, especially in retinoid-resistant acute myeloid leukemia.
authors.affiliation: Division of Hematology/Oncology, Cedars-Sinai Medical Center, University of California, Los Angeles School of Medicine, 8700 Beverly Blvd, Rm 5433, Los Angeles, CA 90048, USA. parkd@cshs.org
authors.forename: Dorothy J
authors.initials: DJ
authors.lastname: Park
authors.forename: Peter T
authors.initials: PT
authors.lastname: Vuong
authors.forename: Sven
authors.initials: S
authors.lastname: de Vos
authors.forename: Dan
authors.initials: D
authors.lastname: Douer
authors.forename: H Phillip
authors.initials: HP
authors.lastname: Koeffler
mesh_terms: D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D019008:Drug Resistance, Neoplasm; D004357:Drug Synergism; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006098:Granulocytes / Q000473:pathology; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute / Q000209:etiology / Q000235:genetics / Q000473:pathology; D009363:Neoplasm Proteins / Q000502:physiology*; D020411:Oligonucleotide Array Sequence Analysis; D015514:Oncogene Proteins, Fusion / Q000502:physiology*; D014212:Tretinoin / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D020298:U937 Cells
chemical_list: D009363:Neoplasm Proteins; D015514:Oncogene Proteins, Fusion; C118318:PLZF-RARalpha fusion protein, human; D014409:Tumor Necrosis Factor-alpha; C093476:promyelocytic leukemia-retinoic acid receptor alpha fusion oncoprotein; D014212:Tretinoin