title: Induction of CCAAT/enhancer binding protein-delta by cytokinins, but not by retinoic acid, during granulocytic differentiation of human myeloid leukaemia cells.
abstract: Cytokinins, purine derivatives that act as hormones to control many processes in plants, are very effective at inducing the granulocytic differentiation of human myeloid leukaemia cells. Isopentenyladenine (IPA), a potent cytokinin, significantly induced the expression of CCAAT/enhancer-binding protein (C/EBP)delta, but not C/EBP alpha protein, whereas all-trans retinoic acid, a well-known inducer of granulocytic differentiation, induced C/EBP alpha but not C/EBP delta protein. Antisense oligonucleotide for C/EBP delta, but not C/EBP alpha or C/EBP beta, effectively suppressed IPA-induced differentiation, suggesting that the expression of C/EBP delta protein is necessary for cytokinin-induced differentiation. Although C/EBP alpha is known to be crucial for granulocytic differentiation, the function of C/EBP delta has not been well documented in the regulation of haematopoiesis. The role of C/EBP delta in the granulocytic differentiation of myeloid leukaemia cells is discussed.
authors.affiliation: Division of Cancer Treatment, Research Institute for Clinical Oncology, Saitama Cancer Center, Ina, Saitama, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Ishii
authors.forename: Takashi
authors.initials: T
authors.lastname: Kasukabe
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Honma
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives* / Q000494:pharmacology; D051743:CCAAT-Enhancer-Binding Protein-delta; D022762:CCAAT-Enhancer-Binding Proteins / Q000378:metabolism* / Q000502:physiology; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D003583:Cytokinins / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000187:drug effects; D006098:Granulocytes / Q000378:metabolism* / Q000473:pathology; D018922:HL-60 Cells; D006801:Humans; D007541:Isopentenyladenosine; D015473:Leukemia, Promyelocytic, Acute / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D014157:Transcription Factors / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D014212:Tretinoin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D022762:CCAAT-Enhancer-Binding Proteins; C497252:CEBPD protein, human; D003583:Cytokinins; D016376:Oligonucleotides, Antisense; D014157:Transcription Factors; D051743:CCAAT-Enhancer-Binding Protein-delta; C001478:N(6)-(delta(2)-isopentenyl)adenine; D014212:Tretinoin; D007541:Isopentenyladenosine; D000225:Adenine