Prolonged activation of the mitogen-activated protein kinase pathway is required for macrophage-like differentiation of a human myeloid leukemic cell line

• Published in: Cell growth & differentiation Vol. 11; no. 4; pp. 191 - 200
• Main Authors: XIAOTANG HU, MOSCINSKI, L. C, VALKOV, N. I, FISHER, A. B, HILL, B. J, ZUCKERMAN, K. S
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA American Association for Cancer Research 01-04-2000
• Subjects: Biological and medical sciences; Blotting, Western; Cell Differentiation - drug effects; Cell Differentiation - physiology; Cell differentiation, maturation, development, hematopoiesis; Cell Nucleus - metabolism; Cell physiology; DNA, Antisense - pharmacology; DNA, Complementary - genetics; DNA-Binding Proteins; Dose-Response Relationship, Drug; Enzyme Activation - drug effects; ets-Domain Protein Elk-1; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Enzymologic; Granulocyte-Macrophage Colony-Stimulating Factor - pharmacology; Humans; Immunohistochemistry; Leukemia, Myeloid - pathology; Leukemia, Myeloid - physiopathology; Macrophages - cytology; Macrophages - drug effects; MAP Kinase Kinase 1; MAP Kinase Signaling System - drug effects; MAP Kinase Signaling System - physiology; Mitogen-Activated Protein Kinase 1 - metabolism; Mitogen-Activated Protein Kinase Kinases - genetics; Mitogen-Activated Protein Kinase Kinases - metabolism; Mitogen-Activated Protein Kinases - genetics; Mitogen-Activated Protein Kinases - metabolism; Molecular and cellular biology; Phosphorylation - drug effects; Protein-Serine-Threonine Kinases - genetics; Protein-Serine-Threonine Kinases - metabolism; Proto-Oncogene Proteins - metabolism; Tetradecanoylphorbol Acetate - pharmacology; Time Factors; Transcription Factors; Transfection; Tumor Cells, Cultured; Human; Enzyme; Transferases; Malignant hemopathy; Activation; Cell differentiation; Myeloid cell; Myeloproliferative syndrome; Signal transduction; Regulation(control); Cell line; Protein kinase; Chronic myelocytic leukemia; Macrophage
• ISSN: 1044-9523; 2377-0732

The role of the mitogen-activated protein kinase (MAPK) signal transduction pathway in the proliferation of mammalian cells has been well established. However, there are relatively few reports concerning cell differentiation being mediated by MAPK. The effect of phorbol 12-myristate 13-acetate (PMA) on cell differentiation and signal transduction in a human myeloid leukemia cell line, TF-1a, was investigated. When TF-1a cells were treated with 10(-6), 10(-7), 10(-8), and 10(-9) M PMA for 24 h, they underwent 98, 93, 91, and 51% macrophage-like differentiation, respectively. PMA treatment rapidly (10 min) induced phosphorylation of MAPK kinase (MEK and p44/42 MAPK), which persisted for at least 24 h. p44/42 MAPK immunoprecipitates from lysates of PMA-treated cells had increased ability to phosphorylate the transcription factor Elk-1. This is important because phosphorylated Elk-1 can be considered an "end-product" of the MAPK pathway. In contrast, treatment of TF-1a cells with granulocyte/macrophage-colony stimulating factor induced only transient activation of MEK and p44/42 MAPK (10-20 min) and an increase (approximately 50%) in cell proliferation, without any change in cellular differentiation. These results suggest that macrophage-like differentiation may be dependent on prolonged activation of the MAPK pathway. Additional support for this conclusion was obtained from experiments showing that treatment of TF-1a cells with antisense oligonucleotides for MEK1 coding sequences prior to adding PMA inhibited macrophage-like differentiation. Furthermore, transient transfection with an inactive, dominant-negative MEK mutant also inhibited PMA-induced differentiation, whereas transient transfection with a plasmid coding for constitutively activated MEK led to macrophage-like differentiation in the absence of PMA.