Interleukin-1 induces c-fos protooncogene expression in cultured human endothelial cells

In the present study we have evaluated the expression of c-fos protooncogene in normal human endothelial cells (HEC) by Northern blot analysis. HEC do not show neither constitutive nor cycloheximide-induced expression of c-fos protooncogene. When HEC were treated with cytokines known to modulate a number of specialized functions of these cells, we observed that, unlike interferon-γ, interleukin-1 (IL-1) and tumor necrosis factor (TNF) were able to induce appreciable levels of c-fos in HEC. Both IL-1α and IL-1β induced c-fos transcripts in HEC. Maximal levels of c-fos mRNA induced by IL-1 were found after 1 hour of treatment, with undetectable levels at 4 and 7 hours. c-fos induction in HEC by IL-1 and TNF may play a role in the acquisition of functional properties induced in HEC by these cytokines.