COX2 converts arachidonate to prostaglandin H2 (PGH2), a committed step in prostanoid synthesis, including production of inflammatory prostaglandins. The conversion of arachidonate to prostaglandin H2 is a 2 step reaction: a cyclooxygenase (COX) reaction which converts arachidonate to prostaglandin G2 (PGG2) and a peroxidase reaction in which PGG2 is reduced to prostaglandin H2 (PGH2). It is constitutively expressed in some tissues in physiological conditions, such as the endothelium, kidney and brain, and is up-regulated under pathological conditions, such as in cancer and inflammation (in contrast to the iso-enzyme PTGS1, which is expressed ubiquitously). Up-regulation of COX2 is also associated with increased cell adhesion, phenotypic changes, resistance to apoptosis and tumor angiogenesis. In cancer cells, COX2 is a key step in the production of prostaglandin E2 (PGE2), which plays important roles in modulating motility, proliferation and resistance to apoptosis. COX2 is naturally inhibited by calcitriol (the active form of Vitamin D). Glucocorticoids chronically trans-repress PTGS2 gene activity in vivo in part by interfering with transcription initiation and elongation. COX2 is a target of NSAID such as aspirin, which can reduce pain and swelling from inflammation driven by COX2.
COX-2; cyclooxygenase; cyclooxygenase 2; cyclooxygenase 2b; Cyclooxygenase-2; Cytochrome c oxidase polypeptide II; Cytochrome c oxidase subunit 2; PGH synthase 2; PGHS-2; PHS II; Prostaglandin G/H synthase 2; Prostaglandin H2 synthase 2; Prostaglandin-endoperoxide synthase 2; prostaglandin-endoperoxide synthase 2 (prostaglandin G/H synthase and cyclooxygenase)