title: Constitutive activation of Stat1 and Stat3 in primary erythroleukemia cells.
abstract: Signal transducers and activators of transcription (Stat) proteins play important roles in the regulation of hematopoiesis as downstream molecules of cytokine signal transduction. Previously, we demonstrated that Stat1 and Stat3 are activated by erythropoietin (EPO) in a human EPO-dependent erythroleukemia cell line UT-7/EPO. We report here that Stat1 and Stat3 are constitutively activated in freshly isolated erythroleukemia cells. In addition, EPO promoted cell growth of these cells, accompanied by enhanced activities of Stat1 and Stat3. Furthermore, mutation in the Statl/Stat3-binding sites of the c-myc gene promoter clearly blocked its promoter activity in EPO-stimulated primary erythroleukemia cells. Thus, Stat1 and Stat3 may support cell growth in part via c-myc gene activation in primary erythroleukemia cells.
authors.affiliation: Department of Medicine, Jichi Medical School, Tochigi, Japan.
authors.forename: Keita
authors.initials: K
authors.lastname: Kirito
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Nagashima
authors.forename: Keiya
authors.initials: K
authors.lastname: Ozawa
authors.forename: Norio
authors.initials: N
authors.lastname: Komatsu
mesh_terms: D000328:Adult; D001665:Binding Sites; D002455:Cell Division / Q000187:drug effects; D004268:DNA-Binding Proteins / Q000502:physiology*; D004921:Erythropoietin / Q000494:pharmacology; D017809:Fatal Outcome; D005260:Female; D015973:Gene Expression Regulation, Leukemic / Q000187:drug effects; D016259:Genes, myc; D006801:Humans; D004915:Leukemia, Erythroblastic, Acute / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D008894:Milk Proteins; D009363:Neoplasm Proteins / Q000502:physiology*; D011401:Promoter Regions, Genetic / Q000235:genetics; D050794:STAT1 Transcription Factor; D050796:STAT3 Transcription Factor; D050799:STAT5 Transcription Factor; D017384:Sequence Deletion; D015534:Trans-Activators / Q000502:physiology*; D015533:Transcriptional Activation / Q000187:drug effects; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D008894:Milk Proteins; D009363:Neoplasm Proteins; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D050799:STAT5 Transcription Factor; D015534:Trans-Activators; D004921:Erythropoietin