Evaluation of WO 2012/177618 A1 and US-2014/0179750 A1: novel small molecule antagonists of prostaglandin-E2 receptor EP2

Eicosanoids in prostate cancer

Many epidemiological studies revealed an association of dietary consumption of fatty acids and prostate cancer. Linoleic acid and alpha-linolenic acid and their derivatives such as arachidonic acid and eicosapentanoic acid are important polyunsaturated fatty acids in animal fats and in many vegetable oils. Their metabolism at the cellular level by enzymes such as lipoxygenases and cycloxygenases produces the group of eicosanoids molecules with many biological roles and activities in a variety of human diseases including cancer. In this review, we describe the biological activities of lipids with focus in eicosanoids and prostate cancer.

Lipopolysaccharide (LPS)-mediated priming of toll-like receptor 4 enhances oxidant-induced prostaglandin E2 biosynthesis in primary murine macrophages

Agonists and pseudo-agonists for toll-like receptor 4 (TLR4) are common in our environment. Thus, human exposure to these agents may result in "priming or sensitization" of TLR4. A body of evidence suggests that LPS-mediated sensitization of TLR4 can increase the magnitude of responses to exogenous agents in multiple tissues. We have previously shown that reactive oxygen and nitrogen species (RONS) stimulate TLR4. There is no evidence that LPS-primed TLR4 can influence the magnitude of responses to oxidants from either endogenous or exogenous sources. In the present study, we directly tested the hypothesis that LPS-primed TLR4 will sensitize primary murine peritoneal macrophages (pM) to oxidant-mediated prostaglandin E2 (PGE₂) production. We used potassium peroxychromate (PPC) and potassium peroxynitrite (PPN) as direct in vitro sources of exogenous RONS. Our results showed that a direct treatment with PPC or PPN alone as sources of exogenous oxidants had a limited effect on PGE₂ biosynthesis. In contrast, pM sensitized by prior incubation with LPS-EK, a TLR4-specific agonist, followed by oxidant stimulation exhibited increased transcriptional and translational expression of cyclooxygenase-2 (COX-2) with enhanced PGE₂ biosynthesis/production only in pM derived from TLR4-WT mice but not in TLR4-KO mice. Thus, we have shown a critical role for LPS-primed TLR4 in oxidant-induced inflammatory phenotypes that have the potential to initiate, propagate and maintain many human diseases.