Constitutive activation of Stat1 and Stat3 in primary erythroleukemia cells.
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.
Kirito
Keita
K
Department of Medicine, Jichi Medical School, Tochigi, Japan.
Nagashima
Toshihiro
T
Ozawa
Keiya
K
Komatsu
Norio
N
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
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