Regulation of TNF-alpha, IL-1 and IL-6 synthesis in differentiating human monoblastoid leukemic U937 cells.
The human monoblastoid tumor cell line U937 was induced to differentiate along the monocyte/macrophage lineage by treatment with 5 x 10(-9) M 12-O-tetradecanoyl phorbol-13-acetate (TPA). Between 2 h and 4 h following TPA-treatment U937 cells started to release significant amounts of TNF-alpha which remained detectable until 8-10 days. A significant IL-1 beta release was measured 24 h-48 h post stimulation and increased levels of IL-1 beta persisted until 20-22 days of culture. In contrast no release of either IL-1 alpha or IL-6 could be detected with 5 x 10(-9) M TPA during the whole time course of the experiments. The sequential induction of TNF-alpha and IL-1 beta appeared to be independently regulated since TNF-alpha release was not required for the onset of IL-1 beta production. Northern-blot analysis confirmed the sequential induction and the long term expression of TNF-alpha and IL-1 beta mRNAs. Western-blot analysis predominantly showed a high molecular weight IL-1 beta protein of about 35 kD. Further investigations on the regulation of cytokine production and release by TPA-differentiated U937 cells revealed that TNF-alpha and IL-1 beta synthesis was not influenced by exogenously added rhTNF-alpha or PGE2, whereas rh gamma-IFN specifically enhanced the IL-1 beta production. Thus, the regulation and intracellular processing of cytokines generated by differentiating U937 cells shows some differences when compared to mature monocytes/macrophages which may be related to the tumorigenic origin of U937 cells or to an incomplete differentiation.
Hass
R
R
Department of Molecular Pharmacology, Medical School, Hannover, F.R.G.
Lonnemann
G
G
Männel
D
D
Topley
N
N
Hartmann
A
A
Köhler
L
L
Resch
K
K
Goppelt-Strübe
M
M
D015152:Blotting, Northern; D002454:Cell Differentiation / Q000187:drug effects*; D002460:Cell Line; D015232:Dinoprostone / Q000494:pharmacology; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology; D007375:Interleukin-1 / Q000096:biosynthesis* / Q000235:genetics; D015850:Interleukin-6 / Q000096:biosynthesis* / Q000235:genetics; D007700:Kinetics; D007948:Leukemia, Monocytic, Acute; D012333:RNA, Messenger / Q000032:analysis / Q000187:drug effects / Q000235:genetics; D011994:Recombinant Proteins / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis* / Q000235:genetics / Q000494:pharmacology
D007375:Interleukin-1; D015850:Interleukin-6; D012333:RNA, Messenger; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma; D015232:Dinoprostone; D013755:Tetradecanoylphorbol Acetate