Breast Cancer Research Today is a free monthly online journal that collates and summarizes the latest research about Breast Cancer, including details on symptoms, genetics, screening, treatment, information. | ||||||||
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15-Deoxy-Delta12,14-prostaglandin J2 induces COX-2 expression through Akt-driven AP-1 activation in human breast cancer cells: a potential role of ROS.Kim EH, Na HK, Kim DH, Park SA, Kim HN, Song NY, Surh YJ National Research Laboratory of Molecular Carcinogenesis and Chemoprevention, College of Pharmacy, Seoul National University, Shinlim-Dong, Kwanak-Gu, Seoul 151-742, South Korea. Recent studies suggest that inflammation is causally linked to carcinogenesis. Cyclooxygenase-2 (COX-2), a rate-limiting enzyme in the biosynthesis of prostaglandins, is inappropriately expressed in various cancers and hence recognized as one of the hallmarks of chronic inflammation-associated malignancies. However, the mechanistic role of COX-2 as a link between inflammation and cancer remains undefined. Here, we report that 15-deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)), one of the final products of COX-mediated arachidonic acid metabolism, upregulates the expression of COX-2 in the human breast cancer MCF-7 cell line. 15d-PGJ(2)-induced COX-2 expression was mediated by activation of Akt and subsequently activator protein-1 (AP-1). Furthermore, 15d-PGJ(2) formed reactive oxygen species, which led to increased phosphorylation of Akt, DNA binding of AP-1 and expression of COX-2. In contrast to 15d-PGJ(2), 9,10-dihydro-15d-PGJ(2) did not elicit any of effects induced by 15d-PGJ(2) in this study, suggesting that an electrophilic carbon center present in 15d-PGJ(2) is critical for COX-2 expression as well activation of upstream signal transduction induced by this cyclopentenone prostaglandin. Taken together, these observations suggest that 15d-PGJ(2) produced by COX-2 overexpression may function as a positive regulator of COX-2 in human breast cancer MCF-7 cells. Published 2 April 2008 in Carcinogenesis, 29(4): 688-95.
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