Granulocyte-macrophage colony-stimulating factor and erythropoietin act competitively to induce two different programs of differentiation in the human pluripotent cell line UT-7.
The UT-7 cell line was established from a patient with a megakaryoblastic leukemia (Komatsu et al, Cancer Res 51: 341, 1991). Its proliferation is strictly dependent on the presence of hematopoietic growth factors including erythropoietin (Epo), granulocyte-macrophage colony-stimulating factor (GM-CSF), and interleukin-3 (IL-3). We investigated the differentiation capacities of this cell line under the action of several growth factors, using immunomarkers, flow cytometry, and ultrastructural techniques. In the presence of GM-CSF and IL-3, eosinophil and basophil promyelocytes were detected, as well as a few cells with erythroid and megakaryocytic (MK) differentiation features. In contrast, Epo induced a marked erythroid differentiation with an increase of glycophorin A expression, accompanied by a few hemoglobinized cells. Differentiation induced by the growth factors took 24 to 48 hours to begin, and increased with cell passages to a plateau at 2 weeks of culture. However, this was not only due to a cell selection because the differential effects of Epo and GM-CSF were observed from a single cell clone and the phenotype could be reversed by opposite growth factors, even after a long period of culture. We subsequently investigated the phenotype of UT-7 in the presence of combinations of Epo, IL-3, and GM-CSF, and showed that GM-CSF and IL-3 act predominantly over Epo. This effect was mediated by a rapid downmodulation of Epo receptors by GM-CSF at messenger RNA and binding sites levels, without a change in receptor affinities. On the other hand, Epo had no effect on number and affinity of GM-CSF receptors. This study shows that UT-7 is a growth factor-dependent pluripotent cell line in which commitment may be directed by a hierarchical action of growth factors through an early and rapid transmodulation of growth factor receptors.
Hermine
O
O
INSERM U.91, Hôpital Henri Mondor, Créteil, France.
Mayeux
P
P
Titeux
M
M
Mitjavila
M T
MT
Casadevall
N
N
Guichard
J
J
Komatsu
N
N
Suda
T
T
Miura
Y
Y
Vainchenker
W
W
D001491:Basophils / Q000166:cytology* / Q000187:drug effects / Q000648:ultrastructure; D002454:Cell Differentiation / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004804:Eosinophils / Q000166:cytology* / Q000187:drug effects / Q000648:ultrastructure; D004900:Erythroblasts / Q000166:cytology* / Q000187:drug effects / Q000648:ultrastructure; D004921:Erythropoietin / Q000494:pharmacology*; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology*; D006801:Humans; D007377:Interleukin-3 / Q000494:pharmacology; D007947:Leukemia, Megakaryoblastic, Acute; D017467:Receptors, Erythropoietin / Q000378:metabolism; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D007377:Interleukin-3; D017467:Receptors, Erythropoietin; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor; D011994:Recombinant Proteins; D004921:Erythropoietin; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D013755:Tetradecanoylphorbol Acetate