Down-regulation of interleukin-3/granulocyte-macrophage colony-stimulating factor receptor β-chain in BCR-ABL+human leukemic cells: association with loss of cytokine-mediated Stat-5 activation and protection from apoptosis after BCR-ABL inhibition

Blood ◽  
2001 ◽  
Vol 97 (9) ◽  
pp. 2846-2853 ◽  
Author(s):  
Nicholas J. Donato ◽  
Ji Y. Wu ◽  
Ling Zhang ◽  
Hagop Kantarjian ◽  
Moshe Talpaz

Abstract 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 of bcr-abl–expressing cells were also evaluated. Expression of bcr-abl in interleukin-3 (IL-3)/granulocyte-macrophage colony-stimulating factor (GM-CSF)–dependent Mo7e cells (MBA) resulted in growth factor independence, constitutive activation of Stat-5 phosphorylation, engagement of mitogen-activated protein (MAP) kinase signals, and increased expression of PTP1B and bcl-xL. STI-571 inhibited cell growth and induced apoptosis in bcr-abl–expressing cells (MBA, K562, BV-173, KBM5) but not in bcr-abl− tumor cells (Mo7e, KG-1, ME-180, Daudi). STI-571–mediated apoptosis correlated with the inhibition of Stat-5 and MAP kinase activation and a reduction in overexpressed bcl-xL but not in PTP1B. Inhibitor had no effect on IL-3/GM-CSF–dependent Mo7e cell signaling and did not prevent activation of the other Jak/Stat pathways (interferon α, IL-3/GM-CSF). However, neither IL-3 nor GM-CSF could reactivate Stat-5 after the STI-571–mediated inhibition of bcr-abl. Expression of the common β-chain of the IL-3/GM-CSF receptor was down-regulated in Stat-5–activated myeloid leukemic cells, suppressing IL-3/GM-CSF signal transduction and the ability of these cytokines to provide apoptotic protection. These studies suggest that bcr-abl activates cytokine-independent mechanisms of survival while inactivating intrinsic cytokine signaling cascades, making bcr-abl+myeloid cells vulnerable to apoptosis after bcr-abl inactivation.

Blood ◽  
1998 ◽  
Vol 91 (1) ◽  
pp. 54-63 ◽  
Author(s):  
Rosemary E. Gale ◽  
Robin W. Freeburn ◽  
Asim Khwaja ◽  
Rajesh Chopra ◽  
David C. Linch

We report here a naturally occurring isoform of the human β chain common to the receptors for granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), and IL-5 (GMRβC) with a truncated intracytoplasmic tail caused by deletion of a 104-bp exon in the membrane-proximal region of the chain. This β intracytoplasmic truncated chain (βIT) has a predicted tail of 46 amino acids, instead of 432 for βC, with 23 amino acids in common with βC and then a new sequence of 23 amino acids. In primary myeloid cells, βIT comprised approximately 20% of the total β chain message, but was increased up to 90% of total in blast cells from a significant proportion of patients with acute leukemia. Specific anti-βITantibodies demonstrated its presence in primary myeloid cells and cell lines. Coexpression of βIT converted low-affinity GMRα chains (KD 2.5 nmol/L) to higher-affinity αβ complexes (KD 200 pmol/L). These could bind JAK2 that was tyrosine-phosphorylated by stimulation with GM-CSF. βITdid not support GM-CSF–induced proliferation when cotransfected with GMRα into CTLL-2 cells. Therefore, it may interfere with the signal-transducing properties of the βC chain and play a role in the pathogenesis of leukemia.


Blood ◽  
1988 ◽  
Vol 72 (4) ◽  
pp. 1329-1332 ◽  
Author(s):  
DC Kaufman ◽  
MR Baer ◽  
XZ Gao ◽  
ZQ Wang ◽  
HD Preisler

Expression of the granulocyte-macrophage colony-stimulating factor (GM- CSF) gene in acute myelocytic leukemia (AML) was assayed by Northern blot analysis. GM-CSF messenger RNA (mRNA) was detected in the freshly obtained mononuclear cells of only one of 48 cases of AML, in contrast with recent reports that GM-CSF mRNA might be detected in half of the cases of AML when RNA is prepared from T-cell- and monocyte-depleted leukemic cells. We did find, however, that expression of the GM-CSF gene was detectable in five of ten cases after in vitro T-cell and monocyte depletion steps. Additional studies suggest that expression of GM-CSF in the bone marrow of the one positive case, rather than being autonomous, was under exogenous control, possibly by a paracrine factor secreted by marrow stromal cells. These studies emphasize the potential for altering in vivo patterns of gene expression by in vitro cell manipulation.


Blood ◽  
1998 ◽  
Vol 91 (1) ◽  
pp. 54-63 ◽  
Author(s):  
Rosemary E. Gale ◽  
Robin W. Freeburn ◽  
Asim Khwaja ◽  
Rajesh Chopra ◽  
David C. Linch

Abstract We report here a naturally occurring isoform of the human β chain common to the receptors for granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), and IL-5 (GMRβC) with a truncated intracytoplasmic tail caused by deletion of a 104-bp exon in the membrane-proximal region of the chain. This β intracytoplasmic truncated chain (βIT) has a predicted tail of 46 amino acids, instead of 432 for βC, with 23 amino acids in common with βC and then a new sequence of 23 amino acids. In primary myeloid cells, βIT comprised approximately 20% of the total β chain message, but was increased up to 90% of total in blast cells from a significant proportion of patients with acute leukemia. Specific anti-βITantibodies demonstrated its presence in primary myeloid cells and cell lines. Coexpression of βIT converted low-affinity GMRα chains (KD 2.5 nmol/L) to higher-affinity αβ complexes (KD 200 pmol/L). These could bind JAK2 that was tyrosine-phosphorylated by stimulation with GM-CSF. βITdid not support GM-CSF–induced proliferation when cotransfected with GMRα into CTLL-2 cells. Therefore, it may interfere with the signal-transducing properties of the βC chain and play a role in the pathogenesis of leukemia.


Blood ◽  
1997 ◽  
Vol 89 (3) ◽  
pp. 863-872 ◽  
Author(s):  
Raffaella Soldi ◽  
Luca Primo ◽  
Maria Felice Brizzi ◽  
Fiorella Sanavio ◽  
Massimo Aglietta ◽  
...  

Abstract Besides the regulation of hematopoiesis, granulocyte-macrophage colony-stimulating factor (GM-CSF) induces the expression of a functional program in endothelial cells (ECs) related to angiogenesis and to their survival in the bone marrow microenvironment. ECs express specific GM-CSF high-affinity binding sites, which mediate the proliferative and migratory response. We now report that ECs express the α and β subunits of GM-CSF receptor (GM-CSFR), and that GM-CSF is able to activate the Janus kinase (JAK)2, a member of the cytosolic tyrosine kinase family, which is known to mediate signals of several non–tyrosine kinase receptors. JAK2 tyrosine phoshorylation, as well as activation of its catalytic activity, is induced by subnanomolar concentrations of GM-CSF and occurs within 3 minutes of stimulation and persists at least for 10 minutes. The effect is specific as inferred by the lack of effect of heat-inactivated GM-CSF or neutralized by specific antibodies and by the finding that interleukin-5, which utilizes a specific α chain and the same β chain of GM-CSFR, does not phosphorylate JAK2. Furthermore, we show that the amount of JAK2 physically associated with GM-CSFR β chain is increased after GM-CSF stimulation and that GM-CSF triggers both β chain and JAK2 tyrosine phosphorylation. Taken together, these results suggest that biologic activities of GM-CSF in vascular endothelium may, in part, be elicited by GM-CSFR–mediated JAK2 activation.


Blood ◽  
1992 ◽  
Vol 79 (11) ◽  
pp. 2880-2887 ◽  
Author(s):  
K Okuda ◽  
JS Sanghera ◽  
SL Pelech ◽  
Y Kanakura ◽  
M Hallek ◽  
...  

Abstract Granulocyte-macrophage colony-stimulating factor (GM-CSF), Interleukin- 3 (IL-3), and Steel Factor (SF) induce proliferation of hematopoietic cells through binding to specific, high-affinity, cell surface receptors. However, little is known about postreceptor signal transduction pathways. In previous studies, we noted that each of these three factors could independently support proliferation of the human MO7 cell line, and also that each factor induced a rapid increase in protein-tyrosyl phosphorylation. Although the proteins phosphorylated on tyrosine by GM-CSF and IL-3 are similar or identical in MO7 cells, many of the proteins that are phosphorylated on tyrosine after SF are different. However, two proteins, p42 and p44, were prominently phosphorylated in response to all three of the factors. In MO7 cells, the tyrosyl phosphorylation of p42 and p44 was transient, peaking at 5 to 15 minutes. In contrast to many of the other proteins which are tyrosyl phosphorylated in response to these factors, phosphorylation of p42 and p44 was temperature-dependent, occurring at 37 degrees C, but not at 4 degrees C. We identified the p42 protein as p42 Mitogen- Activated Protein Kinase (p42mapk, ERK-2) and the p44 as a p42mapk- related protein using monospecific antisera to MAP kinase. GM-CSF, IL- 3, and SF were each found to induce MAP kinase activity when assayed in vitro using myelin basic protein (MBP) as a substrate. Remarkably, we found that GM-CSF-induced tyrosyl phosphorylation of p42 and p44 even in nonproliferative cells (neutrophils) that respond to this CSF, and that p42 and p44 were two of the most prominently tyrosyl phosphorylated proteins following GM-CSF stimulation of these cells. These results implicate p42mapk and p44 as important signal transducing molecules in myeloid cells, and it is likely that these kinases play a role as part of a sequential “kinase cascade” linking growth factor receptors to mitogenesis and other cellular responses.


Blood ◽  
1999 ◽  
Vol 94 (6) ◽  
pp. 1933-1942 ◽  
Author(s):  
F.C. Stomski ◽  
M. Dottore ◽  
W. Winnall ◽  
M.A. Guthridge ◽  
J. Woodcock ◽  
...  

Abstract The common β chain (βc) of the granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), and IL-5 receptors is the major signaling subunit of these receptors coupling ligand binding to multiple biological activities. It is thought that these multiple functions arise as a consequence of the recruitment of specific signaling molecules to tyrosine-phosphorylated residues in the cytoplasmic domain of βc. However, the contribution of serine phosphorylation in βc to the recruitment of signaling molecules is not known. We show here the identification of a phosphoserine motif in the cytoplasmic domain of βc that interacts with the adaptor protein 14-3-3ζ. Coimmunoprecipitation and pull-down experiments with a glutathione S-transferase (GST):14-3-3ζ fusion protein showed that 14-3-3 directly associates with βc but not the GM-CSF receptor  chain. C-terminal truncation mutants of βcfurther showed that a region between amino acids 544 and 626 in βc was required for its association with 14-3-3ζ. This region contains the sequence 582HSRSLP587, which closely resembles the RSXSXP (where S is phosphorylated) consensus 14-3-3 binding site identified in a number of signaling molecules, including Raf-1. Significantly, substitution of582HSRSLP587 for EFAAAA completely abolished interaction of βc with GST–14-3-3ζ. Furthermore, the interaction of βc with GST–14-3-3 was greatly reduced in the presence of a peptide containing the 14-3-3 binding site, but only when 585Ser was phosphorylated. Direct binding experiments showed that the peptide containing phosphorylated 585Ser bound 14-3-3ζ with an affinity of 150 nmol/L. To study the regulation of 585S phosphorylation in vivo, we raised antibodies that specifically recognized 585Ser-phosphorylated βc. Using these antibodies, we showed that GM-CSF stimulation strongly upregulated 585Ser phosphorylation in M1 myeloid leukemic cells. The proximity of the SHC-binding site (577Tyr) to the 14-3-3–binding site (582HSRSLP587) and their conservation between mouse, rat, and human βc but not in other cytokine receptors suggest that they form a distinct motif that may subserve specialized functions associated with the GM-CSF, IL-3, and IL-5 receptors.


1989 ◽  
Vol 9 (9) ◽  
pp. 4109-4112
Author(s):  
Y Shabo ◽  
J Lotem ◽  
L Sachs

Induction of differentiation in one type of clone of mouse myeloid leukemic cells by mouse or human interleukin 6 (IL-6) and in another type of clone by mouse granulocyte-macrophage colony-stimulating factor (GM-CSF) was found to be associated with induction of IL-6 and GM-CSF mRNA and protein. The results indicated that IL-6 and GM-CSF could positively autoregulate their own gene expression during myeloid cell differentiation. It is suggested that this autoregulation may serve to enhance and prolong the signal induced by these proteins in cells transiently exposed to IL-6 or GM-CSF.


Blood ◽  
1998 ◽  
Vol 92 (10) ◽  
pp. 3636-3646 ◽  
Author(s):  
Thamar B. van Dijk ◽  
Belinda Baltus ◽  
Eric Caldenhoven ◽  
Hiroshi Handa ◽  
Jan A.M. Raaijmakers ◽  
...  

High-affinity receptors for interleukin-3 (IL-3), IL-5, and granulocyte-macrophage colony-stimulating factor (GM-CSF) are composed of two distinct subunits, a ligand-specific  chain and a common β chain (βc). Whereas the mouse has two homologous β subunits (βc and βIL-3), in humans, only a single β chain is identified. We describe here the isolation and characterization of the gene encoding the human IL-3/IL-5/GM-CSF receptor β subunit. The gene spans about 25 kb and is divided into 14 exons, a structure very similar to that of the murine βc/βIL-3 genes. Surprisingly, we also found the remnants of a second βc chain gene directly downstream of βc. We identified a functional promoter that is active in the myeloid cell lines U937 and HL-60, but not in HeLa cells. The proximal promoter region, located from −103 to +33 bp, contains two GGAA consensus binding sites for members of the Ets family. Single mutation of those sites reduces promoter activity by 70% to 90%. The 5′ element specifically binds PU.1, whereas the 3′ element binds a yet-unidentified protein. These findings, together with the observation that cotransfection of PU.1 and other Ets family members enhances βc promoter activity in fibroblasts, reinforce the notion that GGAA elements play an important role in myeloid-specific gene regulation.


Blood ◽  
1999 ◽  
Vol 94 (6) ◽  
pp. 1933-1942 ◽  
Author(s):  
F.C. Stomski ◽  
M. Dottore ◽  
W. Winnall ◽  
M.A. Guthridge ◽  
J. Woodcock ◽  
...  

The common β chain (βc) of the granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), and IL-5 receptors is the major signaling subunit of these receptors coupling ligand binding to multiple biological activities. It is thought that these multiple functions arise as a consequence of the recruitment of specific signaling molecules to tyrosine-phosphorylated residues in the cytoplasmic domain of βc. However, the contribution of serine phosphorylation in βc to the recruitment of signaling molecules is not known. We show here the identification of a phosphoserine motif in the cytoplasmic domain of βc that interacts with the adaptor protein 14-3-3ζ. Coimmunoprecipitation and pull-down experiments with a glutathione S-transferase (GST):14-3-3ζ fusion protein showed that 14-3-3 directly associates with βc but not the GM-CSF receptor  chain. C-terminal truncation mutants of βcfurther showed that a region between amino acids 544 and 626 in βc was required for its association with 14-3-3ζ. This region contains the sequence 582HSRSLP587, which closely resembles the RSXSXP (where S is phosphorylated) consensus 14-3-3 binding site identified in a number of signaling molecules, including Raf-1. Significantly, substitution of582HSRSLP587 for EFAAAA completely abolished interaction of βc with GST–14-3-3ζ. Furthermore, the interaction of βc with GST–14-3-3 was greatly reduced in the presence of a peptide containing the 14-3-3 binding site, but only when 585Ser was phosphorylated. Direct binding experiments showed that the peptide containing phosphorylated 585Ser bound 14-3-3ζ with an affinity of 150 nmol/L. To study the regulation of 585S phosphorylation in vivo, we raised antibodies that specifically recognized 585Ser-phosphorylated βc. Using these antibodies, we showed that GM-CSF stimulation strongly upregulated 585Ser phosphorylation in M1 myeloid leukemic cells. The proximity of the SHC-binding site (577Tyr) to the 14-3-3–binding site (582HSRSLP587) and their conservation between mouse, rat, and human βc but not in other cytokine receptors suggest that they form a distinct motif that may subserve specialized functions associated with the GM-CSF, IL-3, and IL-5 receptors.


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