NEOPLASIA STAT 5 Activation by BCR - Abl Contributes to Transformation of K 562 Leukemia Cells
نویسندگان
چکیده
Signal transducers and activators of transcription (STATs) belong to a family of transcription factors that were originally identified as mediators of cytokine-induced gene expression. Recent evidence, however, has shown that certain members of the STAT family, including STAT3, are also involved in cellular transformation. Here we show that STAT5 also plays a role in cellular transformation by the BCR-Abl oncogene. In BCR-Abl transformed K562 cells, STAT5A and 5B are constitutively phosphorylated on tyrosine and are transcriptionally active. Moreover, expression of a dominant negative form of STAT5 shows that active STAT5 is necessary for the growth in soft agar of these cells. These results show that besides STAT3, STAT5 can also be involved in cellular transformation. r 1999 by The American Society of Hematology.
منابع مشابه
Tyrosyl phosphorylation and DNA binding activity of signal transducers and activators of transcription (STAT) proteins in hematopoietic cell lines transformed by Bcr/Abl
Bcr/Abl is a chimeric oncogene that can cause both acute and chronic human leukemias. Bcr/Abl-encoded proteins exhibit elevated kinase activity compared to c-Abl, but the mechanisms of transformation are largely unknown. Some of the biological effects of Bcr/Abl overlap with those of hematopoietic cytokines, particularly interleukin 3 (IL-3). Such effects include mitogenesis, enhanced survival,...
متن کاملDown-regulation of interleukin-3/granulocyte-macrophage colony-stimulating factor receptor b-chain in BCR-ABL1 human leukemic cells: association with loss of cytokine-mediated Stat-5 activation and protection from apoptosis after BCR-ABL inhibition
Several signaling cascades are engaged by expression of the p210 bcr-abl tyrosine kinase, and evidence suggests that these signals drive leukemogenesis. In this report, signaling pathways were examined and compared between cells derived from leukemic patients and cells expressing a bcr-abl construct (MBA). The effects of acute inhibition of bcr-abl with STI-571 on these signals and the survival...
متن کاملBcr-abl Silencing by Specific Small-Interference RNA Expression Vector as a Potential Treatment for Chronic Myeloid Leukemia
Background: RNA interference (RNAi) is the mechanism of gene silencing-mediated messenger RNA degradation by small interference RNA (siRNA), which becomes a powerful tool for in vivo research, especially in the areas of cancer. In this research, the potential use of an expression vector as a specific siRNA producing tool for silencing of Bcr-abl in K562 cell line has been investigated. Methods:...
متن کاملSignal Transducer and Activator of Transcription (STAT)5 Activation by BCR/ABL Is Dependent on Intact Src Homology (SH)3 and SH2 Domains of BCR/ABL and Is Required for Leukemogenesis
Signal transducer and activator of transcription (STAT)5 is constitutively activated in BCR/ ABL-expressing cells, but the mechanisms and functional consequences of such activation are unknown. We show here that BCR/ABL induces phosphorylation and activation of STAT5 by a mechanism that requires the BCR/ABL Src homology (SH)2 domain and the proline-rich binding site of the SH3 domain. Upon expr...
متن کاملPrimitive interleukin 3 null hematopoietic cells transduced with BCR-ABL show accelerated loss after culture of factor-independence in vitro and leukemogenic activity in vivo.
Primitive chronic myeloid leukemia cells display a unique autocrine interleukin 3 (IL-3)/granulocyte-colony-stimluating factor (G-CSF) mechanism that may explain their abnormal proliferation and differentiation control. Here we show that BCR-ABL transduction of primitive Sca-1(+) lin(-) mouse bone marrow (BM) cells causes immediate activation of IL-3, G-CSF, and granulocyte macrophage-colony-st...
متن کامل