The Cyclooxygenase-2 Essay -- Health, Diseases

The cyclooxygenase-2 (cyclooxygenase-2) is a key enzyme in the changeover of arachidonic acid to prostaglandins, which promote cell proliferation, angiogenesis and metastasis, and inhibit apoptosis. Unlike COX-1, which is constitutively expressed isoform, cyclooxygenase-2 is an inducible isoform of cyclooxygenase and which may participate in inflammatory responses and contribute to ardor and malignant neoplastic diseasesthe development of colorectal cancer as thoroughly as new(prenominal) human cancers (1). cyclooxygenase-2 is not detectable detected in nearly normal tissues. However, it but is rapidly induced when stimulated by in response to mitogens, cytokines and tumor promoters, which leads to the leading to increased accumulation of prostanoids in neoplastic and inflamed tissues (2). COX-2 is highly expressed at high levels in intestinal tumors in rodents and humans (1). For example, Mmore than 80% of all colorectal tumors were shown to overexpress COX-2 (3-5). Epidemiolo gic studies have shown that taking aspirin or other nonsteroidal anti-inflammatory drugs on a regular basis could reduce mortality rate from colorectal cancer by 40-50% compared with those who not taking these drugs (1). One feature shared by all of these drugs is their ability to inhibit COX natural action and/or expression (1).Although COX-2 is expressed in 80-90% of human colon carcinoma specimens, not all colorectal cancer cell lines constitutively expressed COX-2. constitutional expression of COX-2 was only detected in a relatively small number of established colorectal carcinoma cell lines (6). For example, human colon adenocarcinoma cell lines, HCT116 and SW480, have been described as COX-2 negative, since they did not express COX-2, neither at mRNA nor at protein level (7). COX-2-derived prostaglandin E2 (PGE2) ... ...t as well as when the conditioned medium will be collected, with doubled parameters in which not only COX-2 mRNA and protein as well as PGE2 levels will be observed, but in addition other relevant molecular markers or factors like those mentioned above.Not only paradoxical observations of COX-2 expression and the functional natural process in human colon cancer cell line have been documented, the role of PGE2 on inflammation seems in like manner paradoxical. Although PGE2 is a potent mediator of inflammation (55), it was suggested that PGE2, endogenous COX products, also inhibit acute allergic inflammation (56). Thus, PGE2 may produce two pro- and anti-inflammatory effects (57). More extensive well-designed experiments are needed to answer us to unveil the secret of COX-2 expression and the functional activity as well as their roles in physiological and pathophysiological conditions.