Proinflammatory cytokines and eicosanoids are central players in intestinal inflammation. IL-1,a key cytokine associated with intestinal mucosal inflammation induces COX-2 expression in human colonic myofibroblasts (CMF) and increased prostaglandin E₂ secretion is associated with inflammatory bowel disease (IBD) and colorectal cancer (CRC). We have previously demonstrated that IL-1- induced COX-2 expression is the result of NF-B and ERK mediated transcription, as well as COX-2 message stabilization which depends on p38, MAPKAPK-2 (MK-2) and human antigen R (HuR) RNA binding protein activation. Lipoxygenase (LOX)-derived hydroxyeicosatetraenoic acids (HETEs) are elevated in inflammatory bowel disease (IBD) and colonic adenomas and "crosstalk" has been observed between the Cox and LOX pathways. Since COX-2 expression is primarily in CMFs in colonic adenomas, we examined the impact of lipoxygenase metabolites, particularly HETEs, on IL-1-induced COX-2 expression in human CMFs. While 5(S), 12(R) and 15(S)-HETEs alone had little to no effect on COX-2 expression, they enhanced IL-1-mediated COX-2 expression 3.6 ± 0.5 fold. Studies utilizing hnRNA amplification and DRB treatment were undertaken to measure COX-2 transcription and message stabilization, respectively. We found that HETEs enhanced IL-1-induced COX-2 mRNA levels in CMF as the result of increased p38, MK-2 and HuR activity, increasing message stability greater than that observed with IL-1 alone. Thus, HETEs can act synergistically with IL-1 to induce COX-2 expression in human CMFs. HETEs may play a role in both colonic inflammation and in increasing the risk of CRC in IBD independently and via induction of COX-2-mediated prostaglandin secretion.