Endogenous production of IL-8 by human colorectal cancer cells and its regulation by cytokines

This study investigated the endogenous production of the pro-inflammatory a nd angiogenic cytokine IL-8 by human colorectal cancer cells. We describe s ubstantial (>0.5 ng/ml) constitutive production of IL-X by certain human co lorectal cancer cell lines without the requirement for exogenous stimulatio n. Tumour cell-derived IL-8;production was upregulated by the addition of t he pro-inflammatory type 1 cytokines TNF alpha, IL-1 beta and IFN gamma. Ad dition of the regulatory type 2 cytokines IL-4 and IL-10 produced paradoxic al stimulation of IL-8 production in certain cell lines and downregulation of IL-8 production in others. These results suggest that tumour-derived cyt okine production may have an important role in patients with colorectal can cer. Furthermore, they demonstrate the complexity of tumour cell cytokine p roduction and highlight the difficulties in developing effective therapeuti c biological response strategies.