V. Fontaine et al., INTERFERON-GAMMA AND INTERLEUKIN-6 INHIBIT PROLIFERATION IN HUMAN-MELANOMA CELLS BY DIFFERENT SIGNALING PATHWAYS, Melanoma research, 8(1), 1998, pp. 24-30
Interferon regulatory factor-1 (IRF-1) is a cell growth inhibitor, ind
uced by cytokines, which transactivates downstream effector genes. The
role of IRF-1 in the antiproliferative effect of interleukin-6 (IL-6)
was investigated using the A375 human melanoma cell line. IL-6 is a s
tronger inhibitor of A375 proliferation compared with interferon-gamma
(IFN gamma). However, in contrast to IFN gamma, IL-6 triggered lower
IRF-1 DNA binding activity and induced barely detectable IRF-1-depende
nt transactivation activity. Furthermore, although IFN gamma induces o
nly activation of signal transducer and activator of transcription (ST
AT) 1, IL-6 activates mainly STAT3. These data suggest that IRF-1 play
s a minor role in the antiproliferative effect of IL-6, which uses alt
ernative signalling events to induce growth inhibition in A375 melanom
a cells. (C) 1998 Rapid Science Ltd.