Published in:
01-12-2011
Prostaglandin E2 EP receptors as therapeutic targets in breast cancer
Authors:
Jocelyn Reader, Dawn Holt, Amy Fulton
Published in:
Cancer and Metastasis Reviews
|
Issue 3-4/2011
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Abstract
Prostaglandins are lipid compounds that mediate many physiological effects. Prostaglandin E2 (PGE2) is the most abundant prostanoid in the human body, and synthesis of PGE2 is driven by cyclooxygenase enzymes including COX-2. Both elevated expression of COX-2 and increased PGE2 levels have been associated with many cancers including breast cancer. PGE2 exerts its effect by binding to the E series of prostaglandin receptors (EP) which are G protein-coupled receptors. Four EP receptor subtypes exist, EP1–4, and each is coupled to different intracellular signaling pathways. As downstream effectors of the COX-2 pathway, EP receptors have been shown to play a role in breast and other malignancies and in cancer metastasis. The role of each EP receptor in malignant behavior is complex and involves the interplay of EP receptor signaling on the tumor cell, on stromal cells, and on host immune effector cells. While preclinical and epidemiological data support the use of nonsteroidal anti-inflammatory drugs and selective COX-2 inhibitors (COXibs) for the prevention and treatment of malignancy, toxicities due to COXibs as well as less than promising results from clinical trials have laboratories seeking alternative targets. As knowledge concerning the role of EP receptors in cancer grows, so does the potential for exploiting EP receptors as therapeutic targets for the treatment or prevention of cancer and cancer metastasis.