Induction of macrophage colony-stimulating factor receptor up-regulation in THP-1 human leukemia cells is dependent on the activation of c-fyn protein tyrosine kinase.
We investigated the role of fyn kinase on the expression of macrophage colony-stimulating factor (M-CSF) receptors (M-CSFR) and macrophage differentiation using a human myelomonocytic leukemic cell line THP-1. Treatment of THP-1 cells with Bryostatin 1 (bryo 1), a potent protein kinase C (PKC) activator, caused a major fraction of them to become adherent (AD) with distinct monocyte/macrophage characteristics. The differentiation was associated with an enhanced expression of M-CSFR and fyn tyrosine kinase activity, occurring primarily on cells in the AD fraction. Scatchard plot analysis showed that the enhanced expression of M-CSFR binding activity was due to an increase in total receptor number per AD cell, rather than an increase in the binding affinity. Fyn antisense (AS) phosphorothioate oligonucleotides (s-oligos) inhibited the up-regulation of both M-CSFR and c-fms transcripts in bryo 1-treated THP-1 cells. In contrast, fyn sense s-oligos did not affect the up-regulation of either M-CSFR or c-fms mRNA in bryo 1-treated cells. In addition, fyn AS s-oligos blocked the expression of AD capacity in bryo 1-treated THP-1 cells. The efficacy of fyn AS s-oligos as macromolecular inhibitors was verified by their ability to lower fyn-associated tyrosine kinase and in vitro autophosphorylation activity in bryo 1-treated THP-1 cells. Taken together, our results show a strong correlation between M-CSFR expression and monocytic differentiation in THP-1 cells, and suggest a possible role of c-fyn tyrosine kinase in mediating these processes.
Li
Y
Y
Department of Immunology, Institute of Basic Medical Sciences, Beijing, China.
Chen
B
B
D054713:Bryostatins; D002454:Cell Differentiation; D004789:Enzyme Activation; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007783:Lactones / Q000494:pharmacology; D018942:Macrolides; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D010587:Phagocytosis; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051076:Proto-Oncogene Proteins c-fyn; D016186:Receptor, Macrophage Colony-Stimulating Factor / Q000235:genetics*; D014407:Tumor Cells, Cultured; D015854:Up-Regulation
D054713:Bryostatins; D007783:Lactones; D018942:Macrolides; D016376:Oligonucleotides, Antisense; D011518:Proto-Oncogene Proteins; C046785:bryostatin 1; D011505:Protein-Tyrosine Kinases; D016186:Receptor, Macrophage Colony-Stimulating Factor; C494957:FYN protein, human; D051076:Proto-Oncogene Proteins c-fyn