TNF and CD95 promote IL-8 gene transactivation via independent elements in colon carcinoma cells

Abstract

The pro-inflammatory cytokine interleukin-8 (IL-8) is produced by HT29 colon epithelial cells following engagement of either CD95 or tumour necrosis factor (TNF) receptors. While the IL-8 promotor elements activated by TNF are well characterised, those responsible for induction of IL-8 by CD95 are unknown. We examined the pathway for CD95 induced IL-8 secretion using two luciferase reporter constructs; the first comprising approximately 500 bp of the IL-8 promotor that includes the nuclear factor kappa B (NFκB), C/EBP and AP-1 sites known to be involved in TNF mediated IL-8 induction; the second that encompasses these elements but extends approximately 1.1 kb further upstream. Although IL-8 ..