The Co-Ordinate Regulation of Lipocortin 1, Cox 2 and CPLA2 by IL-1β in A549 Cells
In the A549 human lung adenocarcinoma cell line, generation of prostaglandin E2 (PGE2) is an important regulator of cell proliferation in vitro (1). Both epidermal growth factor (EGF) and the pro-inflammatory cytokine IL-1β up regulate cell proliferation by inducing PGE2 release. The PGE2 mediated increase in cell proliferation can be inhibited by dexamethasone. The inhibition of PGE2 release by the dexamethasone is mediated via the induction of lipocortin 1 on the surface of A549 cells (1). Furthermore, we have shown the EGF simulated arachidonic acid release, PGE2 release and subsequent cell proliferation can all be repressed by the addition of fragments of lipocortin-1 to the cells (2). These results imply that cell surface lipocortin 1 can regulate arachidonic acid release, and when EGF simulated cells are treated with dexamethasone the increase in cell surface lipocortin 1 is responsible for down-regulating arachidonic acid release, PGE2 release and cell proliferation.
KeywordsA549 Cell A549 Cell Line Arachidonic Acid Release PGE2 Release High Molecular Weight Species
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