Prostaglandin (PG)E2 is a potent mediator of pain and inflammation, and high levels of this lipid mediator are observed in numerous disease states. The inhibition of PGE2 production to control pain and to treat diseases such as rheumatoid arthritis to date has depended on nonsteroidal antiinflammatory agents such as aspirin. However, these agents inhibit the synthesis of all prostanoids. To produce biologically active PGE2, PGE synthases catalyze the isomerization of PGH2 into PGE2. Recently, several PGE synthases have been identified and cloned, but their role in inflammation is not clear. To study the physiological role of the individual PGE synthases, we have generated by targeted homologous recombination a mouse line deficient in microsomal PGE synthase 1 (mPGES1) on the inbred DBA͞1lacJ background. mPGES1-deficient (mPGES1 ؊/؊ ) mice are viable and fertile and develop normally compared with wild-type controls. However, mPGES1 ؊/؊ mice displayed a marked reduction in inflammatory responses compared with mPGES1 ؉/؉ mice in multiple assays. Here, we identify mPGES1 as the PGE synthase that contributes to the pathogenesis of collagen-induced arthritis, a disease model of human rheumatoid arthritis. We also show that mPGES1 is responsible for the production of PGE 2 that mediates acute pain during an inflammatory response. These findings suggest that mPGES1 provides a target for the treatment of inflammatory diseases and pain associated with inflammatory states.arthritis ͉ inflammation ͉ macrophage ͉ knockout ͉ PGE2

Telomerase, a ribonucleic acid-protein complex, adds hexameric repeats of 5'-TTAGGG-3' to the ends of mammalian chromosomal DNA (telomeres) to compensate for the progressive loss that occurs with successive rounds of DNA replication. Although somatic cells do not express telomerase, germ cells and immortalized cells, including neoplastic cells, express this activity. To determine whether the phenotypic differentiation of immortalized cells is linked to the regulation of telomerase activity, terminal differentiation was induced in leukemic cell lines by diverse agents. A pronounced downregulation of telomerase activity was produced as a consequence of the differentiated status. The differentiation-inducing agents did not directly inhibit telomerase activity, suggesting that the inhibition of telomerase activity is in response to induction of differentiation. The loss of telomerase activity was not due to the production of an inhibitor, since extracts from differentiated cells did not cause inhibition of telomerase activity. By using additional cell lineages including epithelial and embryonal stem cells, downregulation of telomerase activity was found to be a general response to the induction of differentiation. These findings provide the first direct link between telomerase activity and terminal differentiation and may provide a model to study regulation of telomerase activity.The ends of eukaryotic chromosomes, called telomeres, consist of an array of tandem repeats of the hexanucleotide 5'-TTAGGG-3'. It is currently assumed that telomeres were evolved to protect the ends of chromosomes against exonucleases and ligases, to prevent the activation of DNA-damage checkpoints, and to counter the loss of terminal DNA segments that occurs when linear DNA is replicated (for a review, see refs.

The NF-KB transcription factor, composed of two proteins, p50 and p65, is a pleiotropic activator that participates in the induction of a wide variety of cellular genes.Various cell adhesion molecules have NF-w.B binding sites and may play an important role in inflammatory response, tumorigenicity, and metastasis. In an earlier study, we demonstrated that adhesion of diverse transformed cells was blocked by antisense inhibition of the p65 subunit of NF-cB. Since cell-substratum interactions play an important role in tumorigenicity, we reasoned that antisense p65 could inhibit tumor- Cell-cell and cell-substratum adhesion plays an important role in the regulation of normal and neoplastic cell growth (1). These adhesion events are mediated by diverse cell adhesion molecules (CAMs) and integrins (1,2). Cell transformation is often associated with qualitative alteration in the integrin repertoire (3). The process of tumor progression is complex and requires malignant cells to modulate their adhesion properties at various points of tumor development (4). Inhibition of NF-KB function by antisense technology elicits a strong block in the adhesion of diverse cell types; if the p65 subunit is inhibited this effect can be observed in most cell types, but if the p50 subunit is inhibited the effect is dependent on the differentiative status of the cells (5). The cellular adhesion of differentiated HL-60 cells stimulated by phorbol 12-myristate 13-acetate is significantly altered, an effect associated with a marked reduction in CD llb integrin expression (6). These results suggested to us that antisense inhibition of p65 function could have profound effects on cellular adhesion.Utilizing diverse tumor-derived cell lines, we demonstrate a pronounced inhibition of adhesion and in vitro growth after treatment with p65 antisense oligonucleotides. Expression of dexamethasone (Dex)-inducible antisense RNA to p65 in a fibrosarcoma cell line inhibited tumorigenicity and caused regression of tumors in nude mice in a Dex-dependentThe publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.manner. Based on these results, we have attempted to establish the in vivo therapeutic efficacy of antisense p65 oligonucleotides utilizing nude mouse tumor models. MATERIALS AND METHODSAntisense Oligonucleotides. The antisense and sense phosphorothioate analogs of oligonucleotides to the 5' end of the different subunits of NF-KB, including the ATG initiation codon (18-to 24-mer), were synthesized using an automated synthesizer (model 394, Applied Biosystems) as described (5,6) following the procedure of Matsukura et al. (7).Cell Lines and Growth Assay. The K-BALB, B-16, SW-480, HT-29, and T-47D cell lines were obtained from the American Type Culture Collection; Rat-1 ras (8), HOS-MNNG (9), and Rat-1 p65A (10) have been described. In four independent experiments, cells (3 x 106) were trypsinized ...

Summary Type 2 diabetes (T2D) is a world-wide epidemic with a medical need for additional targeted therapies. Suppression of hepatic glucose production (HGP) effectively ameliorates diabetes and can be exploited for its treatment. We hypothesized that targeting PGC-1α acetylation in liver, a chemical modification known to inhibit hepatic gluconeogenesis, could be potentially used for treatment of T2D. Thus, we designed a high-throughput chemical screen platform to quantify PGC-1α acetylation in cells and identified small molecules that increase PGC-1α acetylation, suppress gluconeogenic gene expression and reduce glucose production in hepatocytes. Based on the potency and bioavailability, we selected a small molecule, SR-18292, that reduces blood glucose, strongly increases hepatic insulin sensitivity and improves glucose homeostasis in dietary and genetic mouse models of T2D. These studies have important implications for understanding the regulatory mechanisms of glucose metabolism and treatment of T2D.