Regulation of the differentiation of WEHI-3B D+ leukemia cells by granulocyte colony-stimulating factor receptor.
To investigate the role of the G-CSF receptor (G-CSFR) in mediating the action of G-CSF, WEHI-3B D+ murine myelomonocytic leukemia cells were transfected with a plasmid containing the murine G-CSFR gene. Overexpression of G-CSFR in transfected clones was demonstrated by northern blotting, binding of [125I]rhG-CSF and cross-linking experiments. A high level of expression of the G-CSFR did not promote or suppress cellular proliferation or initiate differentiation; however, exposure of transfected cells to G-CSF in suspension culture caused a large percentage of the population to enter a differentiation pathway, as determined by two markers of the mature state, the ability of cells to reduce nitroblue tetrazolium (NBT) and to express the differentiation antigen Mac-1 (CD11b) on the cell surface. Thus, upon treatment with 10 ng/ml of G-CSF, 60% or more of transfected cells exhibited NBT positivity; whereas, in contrast, nontransfected cells exhibited only 6% NBT positivity in response to G-CSF. An eightfold increase in Mac-1 expression over that of the parental line was also observed in transfected cells exposed to G-CSF. The growth rate of the transfected clones was decreased by exposure to G-CSF, presumably due to terminal differentiation. The findings suggest that the predominant function of G-CSF and its receptor in WEHI-3B D+ cells is to mediate differentiation and that the level of the G-CSFR portion of the signal transduction mechanism in this malignant cell line is important for a response to the maturation inducing function of the cytokine.
Li
J
J
Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06510.
Koay
D C
DC
Xiao
H
H
Sartorelli
A C
AC
D000818:Animals; D015152:Blotting, Northern; D002104:Cadmium / Q000494:pharmacology; D019256:Cadmium Chloride; D002454:Cell Differentiation; D002455:Cell Division / Q000187:drug effects; D002712:Chlorides / Q000494:pharmacology; D003432:Cross-Linking Reagents; D016179:Granulocyte Colony-Stimulating Factor / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D007942:Leukemia, Experimental; D051379:Mice; D010957:Plasmids; D012333:RNA, Messenger / Q000378:metabolism; D016188:Receptors, Granulocyte Colony-Stimulating Factor / Q000235:genetics / Q000502:physiology*; D011994:Recombinant Proteins / Q000378:metabolism / Q000494:pharmacology; D014162:Transfection; D014212:Tretinoin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D002712:Chlorides; D003432:Cross-Linking Reagents; D012333:RNA, Messenger; D016188:Receptors, Granulocyte Colony-Stimulating Factor; D011994:Recombinant Proteins; D002104:Cadmium; D016179:Granulocyte Colony-Stimulating Factor; D014212:Tretinoin; D019256:Cadmium Chloride