Jun N-terminal kinase pathway enhances signaling of monocytic differentiation of human leukemia cells induced by 1,25-dihydroxyvitamin D3

• Published in: Journal of cellular biochemistry Vol. 89; no. 6; pp. 1087 - 1101
• Main Authors: Wang, Qing, Wang, Xuening, Studzinski, George P.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 15.08.2003
• Subjects: Anthracenes - pharmacology; AP-1 transcription factor; Blotting, Western; Cell Differentiation - drug effects; differentiation; Dose-Response Relationship, Drug; Electrophoretic Mobility Shift Assay; Enzyme Activation; Enzyme Inhibitors - pharmacology; Ergocalciferols - pharmacology; HL-60 Cells; Humans; JNK Mitogen-Activated Protein Kinases; jun N-terminal kinase; Leukemia - metabolism; leukemia cells; Mitogen-Activated Protein Kinases - metabolism; Monocytes - cytology; Monocytes - drug effects; Phosphorylation - drug effects; Proto-Oncogene Proteins c-jun - drug effects; Proto-Oncogene Proteins c-jun - metabolism; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction - drug effects; Signal Transduction - physiology; Transcription Factor AP-1 - drug effects; Transcription Factor AP-1 - metabolism; U937 Cells; vitamin D
• ISSN: 0730-2312; 1097-4644
• DOI: 10.1002/jcb.10595

Recent studies revealed that the MEK/ERK module of the mitogen‐activated protein kinase (MAPK) signaling cascades is up‐regulated in the early stages of 1α,25‐dihydroxyvitamin D3 (1,25D3)‐induced monocytic differentiation of human leukemia cells HL60. In the present study, we investigated whether another MAPK module, the JNK pathway, also participates in this form of differentiation. We found that the dependence on the concentration of the inducer, the vitamin‐hormone 1,25D3, in two types of human leukemia cells, HL60 and U937, and the kinetics of monocytic differentiation in HL60 cells, parallel the degree of the activation of the JNK pathway. A blockade of JNK signaling by a stable expression of dominant negative (dn) JNK1 mutant in U937 cells resulted in reduced c‐jun phosphorylation, and the differentiation of these cells was markedly decreased. Similarly, inhibition of JNK1 and JNK2 activities by the selective inhibitor SP600125 led to both dose‐dependent reduction of c‐jun and ATF‐2 phosphorylation, and of the differentiation of HL60 cells. In addition, we found that JNK activity is essential for the AP‐1 DNA binding induced by 1,25D3 in HL60 and U937 cells. The results indicate that in cultured human leukemia cells, the JNK pathway participates in the induction of monocytic differentiation by 1,25D3, probably by activating the AP‐1 transcription factor. © 2003 Wiley‐Liss, Inc.