Effects of tumor necrosis factor on cell growth and expression of transferrin receptors in human fibroblasts.
Human recombinant tumor necrosis factor (TNF) stimulated the growth of confluent human fibroblasts (FS-4) in the presence of fetal calf serum. Epidermal growth factor (EGF) similarly stimulated cellular growth; however other mitogenic factors such as insulin, fibroblast growth factor, 12-O-tetradecanoyl-phorbol-12-acetate and Ca2+ ionophore A23187 did not. The growth-stimulating action of TNF was not synergistic with the activity of EGF in the presence of serum. TNF induced a rapid increase in the binding of transferrin to the cell surface, followed by a return to the basal level within 5 min. A similar increase in transferrin binding was observed in FS-4 cells exposed to EGF. In contrast, insulin caused a prolonged stimulation of transferrin binding. These results suggest that TNF and EGF generate similar or identical intracellular signals for cellular growth and the regulation of transferrin receptor expression.
Hori
T
T
Department of Biochemistry, Faculty of Pharmaceutical Sciences, Setsunan University, Osaka, Japan.
Kashiyama
S
S
Oku
N
N
Hayakawa
M
M
Shibamoto
S
S
Tsujimoto
M
M
Nishihara
T
T
Ito
F
F
D002455:Cell Division / Q000187:drug effects; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure*; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D008934:Mitogens / Q000494:pharmacology; D011990:Receptors, Transferrin / Q000187:drug effects / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D007328:Insulin; D008934:Mitogens; D011990:Receptors, Transferrin; D014409:Tumor Necrosis Factor-alpha; D004815:Epidermal Growth Factor