title: FOXO3A as a key molecule for all-trans retinoic acid-induced granulocytic differentiation and apoptosis in acute promyelocytic leukemia.
abstract: All-trans retinoic acid (ATRA) induces granulocytic differentiation and apoptosis in acute promyelocytic leukemia (APL) cells, although the detailed mechanisms are not fully understood. We investigated ATRA-induced cellular responses mediated by the transcription factor FOXO3A in APL cells. FOXO3A was constitutively phosphorylated and localized in the cytoplasm in both APL-derived NB4 cells and primary APL cells. Upon treating the cells with ATRA, FOXO3A phosphorylation was reduced and FOXO3A translocated into the nucleus. In addition, the expression of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), a target molecule for FOXO3A, was increased at the transcriptional and protein levels. As expected, transfection of a short hairpin RNA (shRNA) oligonucleotide specific for FOXO3A significantly inhibited ATRA-induced granulocytic differentiation and apoptosis in NB4 cells. In NB4-derived ATRA-resistant NB4/RA cells, neither FOXO3A nuclear localization nor subsequent TRAIL induction was observed after ATRA treatment. Furthermore, forced expression of active FOXO3A in the nucleus induced TRAIL production and apoptosis in NB4/RA cells. We conclude that activation of FOXO3A is an essential event for ATRA-induced cellular responses in NB4 cells. FOXO3A is a promising target for therapeutic approaches to overcome ATRA resistance in APL.
authors.affiliation: Department of Hematology, Juntendo University School of Medicine, Tokyo 113-8421, Japan.
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Sakoe
authors.forename: Kumi
authors.initials: K
authors.lastname: Sakoe
authors.forename: Keita
authors.initials: K
authors.lastname: Kirito
authors.forename: Keiya
authors.initials: K
authors.lastname: Ozawa
authors.forename: Norio
authors.initials: N
authors.lastname: Komatsu
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D002454:Cell Differentiation / Q000187:drug effects*; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D047369:Chromatin Immunoprecipitation; D005455:Fluorescent Antibody Technique; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors / Q000235:genetics / Q000378:metabolism*; D006098:Granulocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute / Q000378:metabolism / Q000473:pathology*; D010766:Phosphorylation / Q000187:drug effects; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000235:genetics / Q000378:metabolism; D014212:Tretinoin / Q000494:pharmacology*
chemical_list: D000970:Antineoplastic Agents; C499517:FOXO3 protein, human; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; D014212:Tretinoin