Fatty Acid Cyclooxygenase Metabolism of Arachidonic Acid in Human Tumor Cells

The prostaglandins, leukotrienes and related eicosanoids have been implicated as mediators in human malignant disease, particularly in cellular events related to tumor metastasis, cell proliferation, tumor promotion and host immunoregulation (1–23). There is substantial evidence that human tumor cells may synthesize significant quantities of prostaglandins. Elevated production of prostaglandin E2 (PGE2) has been demonstrated in lung cancer patients in vivo (24,25). Other studies have shown that prostanoid biosynthesis is elevated in human tumor tissues in comparison with production in normal human tissues (26–28) and that cultured human tumor cells synthesize significant quantities of prostanoids (29–32). In the present studies, the profiles of prostanoid biosynthesis from endogenous arachidonic acid in 55 established cell lines derived from human tumors of the colon, lung, prostate, ovary, kidney, and the central nervous system were determined. The objective of these studies was the determination of PGH synthase activity in diverse histological classes of human tumor cells in order to discern whether fatty acid cyclooxygenase metabolism of arachidonic acid may be uniquely characteristic of certain histological classes of human tumors.