title: The N-terminal CEBPA mutant in acute myeloid leukemia impairs CXCR4 expression.
abstract: CXC chemokine receptor 4 (CXCR4) is an essential regulator for homing and maintenance of hematopoietic stem cells within the bone marrow niches. Analysis of clinical implications of bone marrow CXCR4 expression in patients with acute myeloid leukemia showed not only higher CXCR4 expression was an independent poor prognostic factor, irrespective of age, white blood cell counts, cytogenetics, and mutation status of NPM1/FLT3-ITD and CEBPA, but also showed CXCR4 expression was inversely associated with mutations of CEBPA, a gene encoding transcription factor C/EBPα. Patients with wild-type CEBPA had significantly higher CXCR4 expression than those with mutated CEBPA. We hypothesized that CEBPA might influence the expression of CXCR4. To test this hypothesis, we first examined endogenous CXCR4 expression in 293T and K562 cells over-expressing wild-type C/EBPα p42 and demonstrated that CXCR4 levels were increased in these cells, whilst the expression of the N-terminal mutant, C/EBPα p30, diminished CXCR4 transcription. We further showed p42 was bound to the CXCR4 promoter by the chromatin immunoprecipitation assays. Induction of p42 in the inducible K562-C/EBPα cell lines increased the chemotactic migration. Moreover, decreased expression of C/EBPα by RNA interference decreased levels of CXCR4 protein expression in U937 cells, thereby abrogating CXCR4-mediated chemotaxis. Our results provide, for the first time, evidence that C/EBPα indeed regulates the activation of CXCR4, which is critical for the homing and engraftment of acute myeloid leukemia cells, while p30 mutant impairs CXCR4 expression.
authors.affiliation: Graduate Institute of Oncology, College of Medicine, National Taiwan University, Taipei; yykuo@ntu.edu.tw.
authors.forename: Yuan-Yeh
authors.initials: YY
authors.lastname: Kuo
authors.affiliation: Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei; Division of Hematology, Department of Internal Medicine, National Taiwan University Hospital, Taipei;
authors.forename: Hsin-An
authors.initials: HA
authors.lastname: Hou
authors.affiliation: Division of Hematology, Department of Internal Medicine, National Taiwan University Hospital, Taipei;
authors.forename: Yin-Kai
authors.initials: YK
authors.lastname: Chen
authors.affiliation: Graduate Institute of Oncology, College of Medicine, National Taiwan University, Taipei;
authors.forename: Li-Yu
authors.initials: LY
authors.lastname: Li
authors.affiliation: Graduate Institute of Oncology, College of Medicine, National Taiwan University, Taipei;
authors.forename: Po-Hsuen
authors.initials: PH
authors.lastname: Chen
authors.affiliation: Division of Hematology, Department of Internal Medicine, National Taiwan University Hospital, Taipei;
authors.forename: Mei-Hsuan
authors.initials: MH
authors.lastname: Tseng
authors.affiliation: Division of Hematology, Department of Internal Medicine, National Taiwan University Hospital, Taipei;
authors.forename: Chi-Fei
authors.initials: CF
authors.lastname: Huang
authors.affiliation: Department of Pathology, National Taiwan University Hospital, Taipei;
authors.forename: Fen-Yu
authors.initials: FY
authors.lastname: Lee
authors.affiliation: Department of Pathology, National Taiwan University Hospital, Taipei;
authors.forename: Ming-Chih
authors.initials: MC
authors.lastname: Liu
authors.affiliation: Department of Pathology, National Taiwan University Hospital, Taipei;
authors.forename: Chia-Wen
authors.initials: CW
authors.lastname: Liu
authors.affiliation: Division of Hematology, Department of Internal Medicine, National Taiwan University Hospital, Taipei; Department of Laboratory Medicine, National Taiwan University Hospital, Taipei;
authors.forename: Wen-Chien
authors.initials: WC
authors.lastname: Chou
authors.affiliation: Biostatistics Consulting Laboratory, Department of Nursing, National Taipei College of Nursing, Taiwan.
authors.forename: Chieh-Yu
authors.initials: CY
authors.lastname: Liu
authors.affiliation: Division of Hematology, Department of Internal Medicine, National Taiwan University Hospital, Taipei;
authors.forename: Jih-Luh
authors.initials: JL
authors.lastname: Tang
authors.affiliation: Division of Hematology, Department of Internal Medicine, National Taiwan University Hospital, Taipei;
authors.forename: Ming
authors.initials: M
authors.lastname: Yao
authors.affiliation: Division of Hematology, Department of Internal Medicine, National Taiwan University Hospital, Taipei;
authors.forename: Hwei-Fang
authors.initials: HF
authors.lastname: Tien
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015153:Blotting, Western; D001853:Bone Marrow / Q000378:metabolism / Q000473:pathology; D022762:CCAAT-Enhancer-Binding Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D016022:Case-Control Studies; D002633:Chemotaxis; D015331:Cohort Studies; D005260:Female; D005434:Flow Cytometry; D005500:Follow-Up Studies; D015972:Gene Expression Regulation, Neoplastic; D006412:Hematopoietic Stem Cells / Q000378:metabolism / Q000473:pathology; D006801:Humans; D020014:K562 Cells; D015470:Leukemia, Myeloid, Acute / Q000235:genetics* / Q000378:metabolism / Q000401:mortality / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy / Q000473:pathology; D009367:Neoplasm Staging; D000090243:Nucleophosmin; D011379:Prognosis; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D019718:Receptors, CXCR4 / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015996:Survival Rate; D020298:U937 Cells; D055815:Young Adult
chemical_list: D022762:CCAAT-Enhancer-Binding Proteins; C515848:CEBPA protein, human; C527276:CXCR4 protein, human; C000716967:NPM1 protein, human; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D019718:Receptors, CXCR4; D000090243:Nucleophosmin