Expression of the c-fgr and hck protein-tyrosine kinases in acute myeloid leukemic blasts is associated with early commitment and differentiation events in the monocytic and granulocytic lineages.

Department of Cell Biology, University of New Mexico School of Medicine, Albuquerque 87131.
Blood (Impact Factor: 9.78). 03/1991; 77(4):726-34.
Source: PubMed

ABSTRACT Two members of the src proto-oncogene family of intracellular tyrosine kinases, c-fgr and hck, are selectively expressed in differentiated myeloid cells. To study the expression of these genes in acute myeloid leukemia (AML) and to determine the specific myeloid lineages and stages of myeloid differentiation at which the expression of these genes is acquired, we used a series of 79 cases of de novo AML as a differentiation model. The levels of c-fgr, hck, and c-fms (encoding the colony-stimulating factor-1 receptor) mRNA transcripts were correlated with the presence of specific cell surface antigens and the morphologic and cytochemical features in these AML blasts. Relatively undifferentiated leukemic myeloblasts with an HLA-DR, CD34, CD33, CD13+/- cell surface immunophenotype (French-American-British [FAB] M1 or M2) were characterized by a lack of c-fms and c-fgr expression, while low levels of c-fms and c-fgr could be detected in undifferentiated myeloblasts (FAB M1 or M2), which also expressed CD14 at low antigen density. The hck transcripts were either undetectable in these cells or were expressed at low levels. In contrast, only hck mRNA transcripts could be identified in blasts with progranulocytic morphology (FAB M3), while c-fms, c-fgr, and hck were all expressed at high levels in blasts with differentiated myelomonocytic or monocytic features (FAB M4 and M5). No c-fms, c-fgr, or hck transcripts were evident in leukemic cells of the erythroid lineage (FAB M6). When undifferentiated leukemic myeloblasts (HLA-DR, CD34, and CD33) were induced to differentiate in vitro to cells with monocytic characteristics, the expression of c-fms, c-fgr, and the CD14 cell surface antigen were induced to high levels, accompanied by the acquisition of hck and CD13 expression. In contrast, when HLA-DR, CD34, and CD33 blasts were induced to differentiate in vitro to cells with granulocytic characteristics, only hck and CD13 expression were induced. Our data suggest that the acquisition of c-fgr and/or hck expression is associated with early commitment and differentiation events in distinct myeloid lineages. Assessment of the expression of these kinases may provide a molecular tool to assign lineage in AML in conjunction with morphology, cytochemistry, and cell surface antigen expression.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The functional consequences of treating rat neutrophils with the potent tyrosine phosphatase inhibitor vanadyl hydroperoxide (pervanadate) has been investigated. Pervanadate induced rapid increases in cellular protein phosphotyrosine content in a dose-dependent manner. This treatment also resulted in a change in morphology of the cells from a rounded to a polarised morphology, with many cells exhibiting uropods, pseudopodia and increased membrane activity. Pervanadate induced a transient actin polymerisation and reorganisation similar to that in agonist-stimulated cells. The pervanadate-induced increases in tyrosine phosphorylation, shape change and actin polymerisation were inhibited by the tyrosine kinase inhibitors tyrphostin and erbstatin, indicating that these phenomena were mediated by the constitutive activity of cellular tyrosine kinases. Double fluorescence experiments demonstrated that there was a co-localisation of tyrosine phosphorylated proteins with F-actin in both pervanadate- and agonist-stimulated neutrophils. Pervanadate also induced spreading of neutrophils on tissue culture substrata with concurrent changes in F-actin localisation including unusual F-actin-containing structures. These results demonstrate that morphological changes and cytoskeletal reorganisation in neutrophils are regulated by tyrosine phosphorylation, and that inhibition of tyrosine phosphatase activity in neutrophils is sufficient to activate motile machinery of these cells. These results suggest that an alternative pathway involved in neutrophil stimulation might be via inhibition of endogenous tyrosine phosphatases rather than activation of tyrosine kinases.
    Journal of Cell Science 12/1993; 106 ( Pt 3):891-901. · 5.33 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Granulocyte colony-stimulating factor (G-CSF) is a glycoprotein of Mr of about 20,000, which stimulates proliferation and differentiation of progenitor cells of neutrophils. Recent clinical application of G-CSF has proven that this hormone is effective in treatment of patients suffering from neutropenia. In the last few years, the biochemical and molecular nature of the G-CSF receptor has been characterized. The G-CSF receptor is a glycoprotein of Mr 100–130,000, and is expressed on the cell surface of various myeloid cells. A homodimer of this polypeptide can bind G-CSF with a high affinity, and transduce G-CSF-triggered growth signals into cells. Its extracellular domain contains a sequence of about 200 amino acids which can be found in various cytokine receptors. In addition, it contains an immunoglobulin-like domain and three fibronectin type III domains. The overall structure of the β-chain (gp130) of the interleukin 6 receptor was found to be very similar to that of the G-CSF receptor.
    Progress in Growth Factor Research 02/1991; DOI:10.1016/S0955-2235(05)80004-3
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The myelodysplastic syndromes comprise a heterogeneous group of neoplastic disorders characterized by ineffective hematopoiesis with an increased tendency to evolve to acute leukemia. Clinically, the common manifestations include peripheral blood cytopenias of one or more lineages and a normal to hyperplastic marrow. MDS has been defined on the basis of morphological criteria, namely the percentage of blast cells in the bone marrow, by the French-American-British study group. Scoring systems have been developed to include such factors as hemoglobin, leukocyte count and age in the evaluation of MDS prognosis. Although useful in the prediction of clinical course and design of therapy regimens, our understanding of the basis of MDS has come from recent advances in molecular analysis of these disorders. This review describes some of the established and recent contributions to our understanding of the molecular basis of the myelodysplastic syndromes. The authors of the present review have been working in the field of myelodysplastic syndromes for several years and have contributed original papers on the molecular pathogenesis of these disorders. In addition, in the present review they have critically examined articles and abstracts published in journals covered by the Science Citation Index and Medline. Cytogenetic anomalies and proto-oncogene abnormalities point to new understanding of the pathogenesis of MDS as a sequence of DNA lesions leading to the evolution of the pre-malignant clone. The prognostic significance of these factors in predicting leukemic transformation and survival remains controversial. Characterization of MDS cells in vitro in response to combinations of exogenous growth factors have not only provided valuable information regarding ineffective hematopoiesis in MDS but have provided a new insight into treatment of MDS. One major development in our understanding of MDS is the possible explanation for the apparent paradox of a cellular marrow in combination with peripheral cytopenias. Extensive premature programmed cell death or apoptosis has been reported to be at least partly responsible. It will remain to be seen whether this fundamental characteristic of myelodysplastic hematopoiesis will play a central role in the drug or genetic based therapy in the myelodysplastic syndromes.
    Haematologica 01/1997; 82(2):191-204. · 5.87 Impact Factor