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Detection of Activated STAT5 in Neoplastic Mast Cells in Patients with Systemic Mastocytosis: Role of c-kit D816V.
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| Zeitschriftentitel: | Blood |
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| Personen und Körperschaften: | , , , , , , , , |
| In: | Blood, 106, 2005, 11, S. 3515-3515 |
| Format: | E-Article |
| Sprache: | Englisch |
| veröffentlicht: |
American Society of Hematology
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| Schlagwörter: |
| Zusammenfassung: | <jats:title>Abstract</jats:title> <jats:p>Recent data suggest that activated STAT5 contributes to growth and differentiation of mast cells (MC) and that STAT5-knock out mice are MC-deficient. We have recently shown that constitutively activated STAT5 acts as a potent oncogenic signaling molecule in hematopoietic progenitor cells (Cancer Cell2005;7:87–99). In the present study, we examined the expression of activated STAT5 in neoplastic MC in systemic mastocytosis (SM) and asked whether the SM-related oncogene c-kit D816V is involved in STAT5-activation. For the immunohistochemical detection of activated tyrosine phosphorylated STAT5 (P-Y-STAT5), we used the specific monoclonal antibody AX1 (Advantex) which does not react with inactive STAT5. In all patients with SM tested (indolent SM, n=11; smouldering SM, n=2; aggressive SM, n=1; mast cell leukemia, n=1; all exhibiting c-kit D816V), MC were found to display P-Y-STAT5. Expression of activated STAT5 was also demonstrable in the c-kit D816V-positive mast cell leukemia-derived cell line HMC-1. The reactivity of HMC-1 cells with AX1 antibody was abrogated by a STAT5-specific blocking-peptide. To define the role of c-kit D816V in STAT5-activation, Ba/F3 cells with doxycycline-inducible expression of c-kit D816V (Ton.kit) were employed. In these cells, induction of c-kit D816V was followed by a massive increase in phosphorylated STAT5 as determined by a specific DNA-binding assay, whereas the total amounts of STAT5-mRNA and of the STAT5-protein showed only a slight increase or remained unchanged. In summary, these data show that neoplastic MC in SM express activated STAT5 (P-Y-STAT5), and that the transforming c-kit mutation D816V leads to persistent activation of STAT5 in these cells.</jats:p> |
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| Umfang: | 3515-3515 |
| ISSN: |
0006-4971
1528-0020 |
| DOI: | 10.1182/blood.v106.11.3515.3515 |