PGE2 Biosynthesis Research Articles

Biological characterization of new inhibitors of microsomal PGE synthase-1 in preclinical models of inflammation and vascular tone.

Microsomal PGE synthase-1 (mPGES-1), the inducible synthase that catalyses the terminal step in PGE2 biosynthesis, is of high interest as therapeutic target to treat inflammation. Inhibition of mPGES-1 is suggested to be safer than traditional NSAIDs, and recent data demonstrate anti-constrictive effects on vascular tone, indicating new therapeutic opportunities. However, there is a lack of potent mPGES-1 inhibitors lacking interspecies differences for conducting in vivo studies in relevant preclinical disease models. Potency was determined based on the reduction of PGE2 formation in recombinant enzyme assays, cellular assay, human whole blood assay, and air pouch mouse model. Anti-inflammatory properties were assessed by acute paw swelling in a paw oedema rat model. Effect on vascular tone was determined with human ex vivo wire myography. We report five new mPGES-1 inhibitors (named 934, 117, 118, 322, and 323) that selectively inhibit recombinant human and rat mPGES-1 with IC50 values of 10-29 and 67-250 nM respectively. The compounds inhibited PGE2 production in a cellular assay (IC50 values 0.15-0.82 μM) and in a human whole blood assay (IC50 values 3.3-8.7 μM). Moreover, the compounds blocked PGE2 formation in an air pouch mouse model and reduced acute paw swelling in a paw oedema rat model. Human ex vivo wire myography analysis showed reduced adrenergic vasoconstriction after incubation with the compounds. These mPGES-1 inhibitors can be used as refined tools in further investigations of the role of mPGES-1 in inflammation and microvascular disease.

Tumor cells hijack enteric glia to activate colon cancer stem cells and stimulate tumorigenesis.

BackgroundColon cancer stem cells (CSCs), considered responsible for tumor initiation and cancer relapse, are constantly exposed to regulatory cues emanating from neighboring cells present in the tumor microenvironment. Among these cells are enteric glial cells (EGCs) that are potent regulators of the epithelium functions in a healthy intestine. However, whether EGCs impact CSC-driven tumorigenesis remains unknown.MethodsImpact of human EGC primary cultures or a non-transformed EGC line on CSCs isolated from human primary colon adenocarcinomas or colon cancer cell lines with different p53, MMR system and stemness status was determined using murine xenograft models and 3D co-culture systems. Supernatants of patient-matched human primary colon adenocarcinomas and non-adjacent healthy mucosa were used to mimic tumor versus healthy mucosa secretomes and compare their effects on EGCs.FindingsOur data show that EGCs stimulate CSC expansion and ability to give rise to tumors via paracrine signaling. Importantly, only EGCs that were pre-activated by tumor epithelial cell-derived soluble factors increased CSC tumorigenicity. Pharmacological inhibition of PGE2 biosynthesis in EGCs or IL-1 knockdown in tumor epithelial cells prevented EGC acquisition of a pro-tumorigenic phenotype. Inhibition of PGE2 receptor EP4 and EGFR in CSCs inhibited the effects of tumor-activated EGCs.InterpretationAltogether, our results show that EGCs, once activated by the tumor, acquire a pro-tumorigenic phenotype and stimulate CSC-driven tumorigenesis via a PGE2/EP4/EGFR-dependent pathway.FundingThis work was supported by grants from the French National Cancer Institute, La Ligue contre le Cancer, the ‘Région des Pays de la Loire’ and the UNC Lineberger Comprehensive Cancer Center.

Microsomal Prostaglandin E2 Synthase-1 as a New Macromolecular Drug Target in the Prevention of Inflammation and Cancer.

Cancer is one of the most life-threatening diseases worldwide. Since inflammation is considered to be one of the known characteristics of cancer, the activity of PGE2 has been paired with different tumorigenic steps such as increased tumor cell proliferation, resistance to apoptosis, increased invasiveness, angiogenesis and immunosuppression. It has been successfully demonstrated that inhibition of mPGES-1 prevented inflammation in preclinical studies. However, despite the crucial roles of mPGEs-1 and PGE2 in tumorigenesis, there is not much in vivo study on mPGES-1 inhibition in cancer therapy. The specificity of mPGEs-1 enzyme and its low expression level under normal conditions makes it a promising drug target with a low risk of side effects. A comprehensive literature search was performed for writing this review. An updated view on PGE2 biosynthesis, PGES isoenzyme family and its pharmacology and the latest information about inhibitors of mPGES-1 have been discussed. In this study, it was aimed to highlight the importance of mPGES-1 and its inhibition in inflammationrelated cancer and other inflammatory conditions. Information about PGE2 biosynthesis, its role in inflammationrelated pathologies were also provided. We kept the noncancer-related inflammatory part short and tried to bring together promising molecules or scaffolds. The information provided in this review might be useful to researchers in designing novel and potent mPGES-1 inhibitors for the treatment of cancer and inflammation.

15‐Hydroperoxy‐PGE2: Intermediate in Mammalian and Algal Prostaglandin Biosynthesis

AbstractArachidonic‐acid‐derived prostaglandins (PGs), specifically PGE2, play a central role in inflammation and numerous immunological reactions. The enzymes of PGE2 biosynthesis are important pharmacological targets for anti‐inflammatory drugs. Besides mammals, certain edible marine algae possess a comprehensive repertoire of bioactive arachidonic‐acid‐derived oxylipins including PGs that may account for food poisoning. Described here is the analysis of PGE2 biosynthesis in the red macroalga Gracilaria vermiculophylla that led to the identification of 15‐hydroperoxy‐PGE2, a novel precursor of PGE2 and 15‐keto‐PGE2. Interestingly, this novel precursor is also produced in human macrophages where it represents a key metabolite in an alternative biosynthetic PGE2 pathway in addition to the well‐established arachidonic acid‐PGG2‐PGH2‐PGE2 route. This alternative pathway of mammalian PGE2 biosynthesis may open novel opportunities to intervene with inflammation‐related diseases.

15-Hydroperoxy-PGE2 : Intermediate in Mammalian and Algal Prostaglandin Biosynthesis.

Arachidonic‐acid‐derived prostaglandins (PGs), specifically PGE2, play a central role in inflammation and numerous immunological reactions. The enzymes of PGE2 biosynthesis are important pharmacological targets for anti‐inflammatory drugs. Besides mammals, certain edible marine algae possess a comprehensive repertoire of bioactive arachidonic‐acid‐derived oxylipins including PGs that may account for food poisoning. Described here is the analysis of PGE2 biosynthesis in the red macroalga Gracilaria vermiculophylla that led to the identification of 15‐hydroperoxy‐PGE2, a novel precursor of PGE2 and 15‐keto‐PGE2. Interestingly, this novel precursor is also produced in human macrophages where it represents a key metabolite in an alternative biosynthetic PGE2 pathway in addition to the well‐established arachidonic acid‐PGG2‐PGH2‐PGE2 route. This alternative pathway of mammalian PGE2 biosynthesis may open novel opportunities to intervene with inflammation‐related diseases.

EP2 Receptor Blockade Attenuates COX-2 Upregulation During Intestinal Inflammation.

High levels of PGE2 have been implicated in the pathogenesis of intestinal inflammatory disorders such as necrotizing enterocolitis (NEC) and peritonitis. However, PGE2 has a paradoxical effect: its low levels promote intestinal homeostasis, whereas high levels may contribute to pathology. These concentration-dependent effects are mediated by four receptors, EP1-EP4. In this study, we evaluate the effect of blockade of the low affinity pro-inflammatory receptors EP1 and EP2 on expression of COX-2, the rate-limiting enzyme in PGE2 biosynthesis, and on gut barrier permeability using cultured enterocytes and three different models of intestinal injury. PGE2 upregulated COX-2 in IEC-6 enterocytes, and this response was blocked by the EP2 antagonist PF-04418948, but not by the EP1 antagonist ONO-8711 or EP4 antagonist E7046. In the neonatal rat model of NEC, EP2 antagonist and low dose of COX-2 inhibitor Celecoxib, but not EP1 antagonist, reduced NEC pathology as well as COX-2 mRNA and protein expression. In the adult mouse endotoxemia and cecal ligation/puncture models, EP2, but not EP1 genetic deficiency decreased COX-2 expression in the intestine. Our results indicate that the EP2 receptor plays a critical role in the positive feedback regulation of intestinal COX-2 by its end-product PGE2 during inflammation and may be a novel therapeutic target in the treatment of NEC.

Design and synthesis of a novel mPGES-1 lead inhibitor guided by 3D-QSAR CoMFA

The search of novel mPGES-1 inhibitors has recently intensified probably due to the superior safety in comparison to existing anti-inflammatory drugs. Although two mPGES-1 inhibitors have entered clinical trials, none has yet reached the market. In this study, we performed modifications guided by 3D-QSAR CoMFA on 2, which is an unsymmetrical curcumin derivative with low binding affinity towards mPGES-1. To counter the PAINS properties predicted for 2, the diketone linker was replaced with a pyrazole ring. On the other hand, both prenyl and carboxylate ester groups were introduced to improve the activity. When tested in vitro, 11 suppressed PGE2 biosynthesis in activated macrophages and showed promising human mPGES-1 inhibition in microsomes of interleukin-1β-stimulated A549 cells. Altogether, 11 has been identified as a potential mPGES-1 inhibitor and could be a promising lead for a novel class of mPGES-1 inhibitors.

Understanding the tumour micro-environment communication network from an NOS2/COX2 perspective.

Recent findings suggest that co-expression of NOS2 and COX2 is a strong prognostic indicator in triple-negative breast cancer patients. These two key inflammation-associated enzymes are responsible for the biosynthesis of NO and PGE2 , respectively, and can exert their effect in both an autocrine and paracrine manner. Impairment of their physiological regulation leads to critical changes in both intra-tumoural and intercellular communication with the immune system and their adaptation to the hypoxic tumour micro-environment. Recent studies have also established a key role of NOS2-COX2 in causing metabolic shift. This review provides an extensive overview of the role of NO and PGE2 in shaping communication between the tumour micro-environment composed of tumour and immune cells that in turn favours tumour progression and metastasis. LINKED ARTICLES: This article is part of a themed section on Nitric Oxide 20 Years from the 1998 Nobel Prize. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.2/issuetoc.

An Insect Prostaglandin E2 Synthase Acts in Immunity and Reproduction.

Eicosanoids, oxygenated metabolites of C20 polyunsaturated fatty acids (PUFAs), mediate fundamental physiological processes, including immune reactions and reproduction, in insects. Prostaglandins (PGs) make up one group of eicosanoids, of which PGE2 is a relatively well-known mediator in various insect taxa. While PG biosynthesis has been reported, the specific biosynthetic pathway for PGE2 is not known in insects. Here, we posed the hypothesis that Se-mPGES2 mediates biosynthesis of physiologically active PGE2 through its cognate protein. To test this hypothesis, we interrogated a transcriptome of the lepidopteran insect, Spodoptera exigua, to identify a candidate PGE2 synthase (Se-mPGES2) and analyzed its sequence and expression. Its predicted amino acid sequence contains a consensus thioredoxin homology sequence (Cys-x-x-Cys) responsible for catalytic activity along with an N-terminal membrane-associated hydrophobic domain and C-terminal cytosolic domain. It also shares sequence homology (36.5%) and shares almost overlapping three dimensional structures with a membrane-bound human PGES2 (mPGES2). Se-mPGES2 was expressed in all developmental stages with high peaks during the late larval instar and adult stages. Immune challenge significantly up-regulated its expression levels in hemocytes and fat body. Injecting double-stranded RNA (dsRNA) specific to Se-mPGES2 significantly impaired two cellular immune responses, hemocyte-spreading behavior and nodule formation following bacterial challenge. Humoral immunity was also significantly suppressed, registered as reduced phenoloxidase activity and antimicrobial peptide expression levels. The suppressed immune responses were reversed following PGE2, but not arachidonic acid (AA), treatments. RNAi treatments also reduced the egg-laying behavior of females. Control females mated with the RNAi-treated males led to substantially reduced egg-laying behavior, which was also reversed following PGE2 injections into females. These results strongly bolster our hypothesis that Se-mPGES2 acts in the biosynthesis of PGE2, a crucial biochemical signal mediating immune and reproductive physiology of S. exigua.

From the Editor’s desk....: July 2018

From the Editor’s desk....: July 2018

Identification of multi-target inhibitors of leukotriene and prostaglandin E2 biosynthesis by structural tuning of the FLAP inhibitor BRP-7

Leukotrienes (LTs) and prostaglandin (PG)E2 are enzymatically produced from arachidonic acid and represent highly bioactive lipid mediators with pro-inflammatory functions. Here, we report on novel multi-target inhibitors that potently and dually interfere with 5-lipoxygenase-activating protein (FLAP) and microsomal prostaglandin E2 synthase (mPGES)-1 in LT and PGE2 biosynthesis, based on the previously identified selective FLAP inhibitor BRP-7 (8, IC50 = 0.31 μM). C (5)-substitution of the benzimidazole ring of BRP-7 by carboxylic acid and its bioisosteres provided compounds, exemplified by 57 that potently suppress LT formation (IC50 = 0.05 μM) by targeting FLAP along with inhibition of mPGES-1 (IC50 = 0.42 μM). Besides FLAP, also 5-lipoxygenase (5-LO) and LTC4 synthase activities were inhibited by 57, albeit with lower potency (IC50 = 0.6 and 6.2 μM) than FLAP. Docking studies and molecular dynamic simulations with FLAP, mPGES-1 and 5-LO provide valuable insights into potential binding interactions of the inhibitors with their targets. Together, these novel benzimidazole derivatives may possess potential as leads for development of effective anti-inflammatory drugs with multi-target properties for dually inhibiting LT and PGE2 production.

Structures and anti-inflammatory properties of 4-halogenated -mofebutazones

The crystal structures of the 4-halogenated (hal: F, Cl, Br)-4-butyl-1-phenyl-1,3-pyrolidine-dione (mofebutazone) are determined, and compared with their solution structures. The racemic 4-halogenated mofebutazone approximants crystallize in a monoclinic space group with four molecules in the unit cell. The 4-hal-mofebutazone molecules reveal strong hydrogen bonding between the hydrogen atom located at the N-2 nitrogen atom and a carbonyl oxygen atom of an adjacent 4-hal-mofebutazone molecule. The hydrogen bond angle for 4-Br-mifebutazone N (2)H (1)⋯O (1) is 173(3) °, so that the hydrogen bond is essentially linear indicating an infinite chain hydrogen bond network. The 3d and 2d structures are stabilized by π-π and σ-π interactions, short intermolecular distances, and apolar forces between adjacently stacked phenyl rings. Small-angle-X-ray scattering (SAXS) experiments and osmometric measurements reveal the presence of dimers for the 4-hal-mofebutazone molecules. Molecular simulations indicate similar solution structure factors for the 4-hal-mofebutazones solutions, S(Q), and in the solid state. There is a strong indication that the [1,1,0], [1,0,0], and [1,0,0] periodicities of the 4-Br, 4-Cl and 4-F-mofebutazone in the crystalline solid state were also present in the solution phase. The biochemical and cellular activities of the different 4-hal-mofebutazones were monitored by the magnitude of their inhibition of the PGE2 biosynthesis through the cyclo-oxygenase (COX-1) in macrophages, and on the inhibition of LTD4 (5-lipoxygenase) in polymorphonuclear leukocytes.

Hypoxia-Induced Downregulation of DUSP-2 Phosphatase Drives Colon Cancer Stemness.

Cancer stem-like cells (CSC) evolve to overcome the pressures of reduced oxygen, nutrients or chemically induced cell death, but the mechanisms driving this evolution are incompletely understood. Here, we report that hypoxia-mediated downregulation of the dual specificity phosphatase 2 (DUSP2) is critical for the accumulation of CSC in colorectal cancer. Reduced expression of DUSP2 led to overproduction of COX-2-derived prostaglandin E2, which promoted cancer stemness via the EP2/EP4 signaling pathways. Genetic and pharmacological inhibition of PGE2 biosynthesis or signal transduction ameliorated loss-of-DUSP2-induced tumor growth and cancer stemness. Genome-wide profile analysis revealed that genes regulated by DUSP2 were similar to those controlled by histone deacetylase. Indeed, treatment with novel histone deacetylase inhibitors abolished hypoxia-induced DUSP2 downregulation, COX-2 overexpression, cancer stemness, tumor growth, and drug resistance. Our findings illuminate mechanisms of cancer stemness and suggest new cancer therapy regimens. Cancer Res; 77(16); 4305-16. ©2017 AACR.

Cytosolic Prostaglandin E Synthase Is Involved in c-Fos Expression in Rat Fibroblastic 3Y1 Cells.

Cytosolic prostaglandin (PG) E synthase (cPGES/p23) plays a role in the biosynthesis of PGE2 and in the molecular chaperone machinery. Studies of knockout mice lacking cPGES/p23 have demonstrated that cPGES/p23 is essential in fetal mouse development. A cDNA microarray analysis revealed that a lack of cPGES/p23 decreases the expression of some immediate early genes, such as c-fos and activating transcription factor 3 (ATF3). Here we report the involvement of cPGES/p23 in c-Fos expression. A stable knockdown of cPGES/p23 in cultured fibroblasts not only reduced serum-induced c-Fos expression, but also decreased the phosphorylation of extracellular signal regulated kinase (ERK). These results suggest that cPGES/p23 is involved in the activation of ERK to promote c-Fos expression.

Effects of Geranyloxycinnamic Acids on COX‐2 and iNOS Functionalities in LPS‐Stimulated U937 Mononuclear Cells

AbstractA series of naturally occurring and semisynthetic O‐geranyl cinnamic acids and their conjugates with the iNOS inhibitor Nω‐nitro‐L‐arginine methyl ester have been synthesized and evaluated for their effects on expressions of COX‐2 and iNOS, antioxidant activity, and PGE2 and NO production in LPS‐stimulated U937 mononuclear cells. All adducts showed little or no effect on iNOS functionality in terms of NO release. A much more significant activity has been recorded on PGE2 biosynthesis for which the sample substituted with a ‐NO2 group in position 3 of the aromatic ring revealed an effect in the nM range both for the L‐NAME conjugated product and the parent compound (IC50=0.71 μM and 0.1 μM respectively). Preliminary docking studies have been carried out to clarify the mechanism of COX‐2 inhibition, and they suggest that the geranyloxy side chain is likely to play an important role for the observed activity and that structural modifications are able to tune such effects.

잘피 추출물의 UVB로 손상을 유도한 각질형성세포에 대한 항염 효능

Objectives : In order to confirm whether extracts of different parts of Zostera marina (ZM), a marine flowering plant, can be used as cosmetic ingredients, this study evaluated their cytotoxicity and cytoprotective effects against ultraviolet B (UVB). Inflammatory responses induced by UV stimuli are also associated with the aging of the skin.Methods : We investigated the effects of ZM extracts on cells through the water soluble tetrazolium salt-1(WST-1) assay for cell viability. In order to investigate the anti-inflammatory effects, we evaluated the suppression of Cyclooxygenase-2 (COX-2) expression by ZM extracts in HaCaT cells with UVB-induced damages, and also evaluated the production of Prostaglandin E₂ (PGE₂) in RAW 264.7 cells with LPS-induced damages.Results : High cell viabilities above 90% were observed in all types of ZM extracts, except for whole ZM extract at 0.5 mg/ml; in keratinocytes with UVB-induced damages, the cell viabilities were above 80% when treated with all types of ZM extracts. We confirmed their anti-inflammatory effects by investigating the suppression of inflammatory mediators. In keratinocytes with UVB-induced damages, COX-2 expression decreased in the experimental group treated with ZM extract. Similarly, in RAW 264.7 cells where inflammation was induced with LPS, the biosynthesis of PGE₂ was inhibited.Conclusion : These results suggest that ethanol extracts from Zostera marina may have value as the potential anti-inflammatory medicinal plant. Also based on the abovementioned results, ZM extract protects skin cells from UV-induced damages, and thus can be used in topically applied products for skin protection.

Novel concepts on the role of prostaglandins on luteal maintenance and maternal recognition and establishment of pregnancy in ruminants

In ruminants, the corpus luteum (CL) of early pregnancy is resistant to luteolysis. Prostaglandin (PG)E2 is considered a luteoprotective mediator. Early studies indicate that during maternal recognition of pregnancy (MRP) in ruminants, a factor(s) from the conceptus or gravid uterus reaches the ovary locally through the utero-ovarian plexus (UOP) and protects the CL from luteolysis. The local nature of the embryonic antiluteolytic or luteoprotective effect precludes any direct effect of a protein transported or acting between the gravid uterus and CL in ruminants. During MRP, interferon tau (IFNT) secreted by the trophoblast of the conceptus inhibits endometrial pulsatile release of PGF2α and increases endometrial PGE2. Our recent studies indicate that (1) luteal PG biosynthesis is selectively directed toward PGF2α at the time of luteolysis and toward PGE2 at the time of establishment of pregnancy (ESP); (2) the ability of the CL of early pregnancy to resist luteolysis is likely due to increased intraluteal biosynthesis and signaling of PGE2; and (3) endometrial PGE2 is transported from the uterus to the CL through the UOP vascular route during ESP in sheep. Intrauterine co-administration of IFNT and prostaglandin E2 synthase 1 (PGES-1) inhibitor reestablishes endometrial PGF2α pulses and regresses the CL. In contrast, intrauterine co-administration of IFNT and PGES-1 inhibitor along with intraovarian administration of PGE2 rescues the CL. Together, the accumulating information provides compelling evidence that PGE2 produced by the CL in response to endometrial PGE2 induced by pregnancy may counteract the luteolytic effect of PGF2α as an additional luteoprotective mechanism during MRP or ESP in ruminants. Targeting PGE2 biosynthesis and signaling selectively in the endometrium or CL may provide luteoprotective therapy to improve reproductive efficiency in ruminants.

Proresolving and cartilage-protective actions of resolvin D1 in inflammatory arthritis.

Rheumatoid arthritis (RA) is a debilitating disease characterized by persistent accumulation of leukocytes within the articular cavity and synovial tissue. Metabololipidomic profiling of arthritic joints from omega-3 supplemented mice identified elevated levels of specialized proresolving lipid mediators (SPM) including resolvin D1 (RvD1). Profiling of human RA synovial fluid revealed physiological levels of RvD1, which — once applied to human neutrophils — attenuated chemotaxis. These results prompted analyses of the antiarthritic properties of RvD1 in a model of murine inflammatory arthritis. The stable epimer 17R-RvD1 (100 ng/day) significantly attenuated arthritis severity, cachexia, hind-paw edema, and paw leukocyte infiltration and shortened the remission interval. Metabololipidomic profiling in arthritic joints revealed 17R-RvD1 significantly reduced PGE2 biosynthesis, while increasing levels of protective SPM. Molecular analyses indicated that 17R-RvD1 enhanced expression of genes associated with cartilage matrix synthesis, and direct intraarticular treatment induced chondroprotection. Joint protective actions of 17R-RvD1 were abolished in RvD1 receptor–deficient mice termed ALX/fpr2/3–/–. These investigations open new therapeutic avenues for inflammatory joint diseases, providing mechanistic substance for the benefits of omega-3 supplementation in RA.

Abstract PR05: Low dose aspirin that reduces mortality from lung adenocarcinoma inhibits both platelet COX-1 and the biosynthesis of PGE2

Abstract Background: Meta-analysis of the trials evaluating the effect of aspirin on cardiovascular outcomes demonstrated that aspirin prevented mortality from adenocarcinomas by 47% and reduced metastasis by 46%. Equivalent benefit was seen with both high and low doses of aspirin. We hypothesize that low dose aspirin blocks metastasis by inhibiting platelet COX-1 and also by inhibiting the biosynthesis of the pro-metastatic PGE2. Methods and Results: The effect of a range of doses of aspirin on PGE2 biosynthesis in three lung adenocarcinoma cell lines was compared with that in washed platelets. PGE2 was measured by GC/MS. In the cancer cell lines, aspirin inhibits COX-2-dependent PGE2 production with IC50s equivalent to or less than that for platelet COX-1. The IC50s were: Platelet = 19.8 ± 1.5 μM; H2122 = 19.5 ± 5 μM; HCC827 = 3.9 ± 2 μM; A549 = 1.6 ± 0.4 μM. To explore the extra-platelet effects of low dose aspirin in vivo, we examined the effect of aspirin 81 mg daily for 2 weeks on the biosynthesis of PGE2 and prostacyclin as reflected by their respective urinary metabolites in 54 healthy humans. The PGE2 metabolite was measured by LC/MS/MS and the prostacyclin metabolite by GC/MS. This dose of aspirin inhibited PGE2 production by 45% (p < 0.0001) and reduced prostacyclin by 37% (p < 0.0001). Adherence of platelets to tumor cells facilitates metastasis. We determined the effect of adherence of ADP-activated washed platelets to lung adenocarcinoma cells (A549) on the PGE2 biosynthetic pathway. COX-2 expression was determined by Western blot, and cytosolic calcium by Fura-2 AM. Activated platelets increased cytosolic calcium in A549 cells by 22% (p < 0.001), increased expression of COX-2 by 8.6 fold (p<0.0001) and increased PGE2 biosynthesis by 8.1 fold (p < 0.0001), indicating that PGE2 production by tumor cells is enhanced by activated platelets. Conclusion: These findings form the basis for a hypothesis that the remarkable effect of low dose aspirin on adenocarcinoma prevention and reduction in metastatic behavior could result from inhibition of platelet activation in concert with inhibition of platelet-induced PGE2 biosynthesis and direct inhibition of the catalytic activity COX-2 in circulating tumor cells. Work funded by the Thoracic Program of the Vanderbilt Ingram Cancer Center Citation Format: John Oates, Pierre Massion, Bjorn Knollmann, James Smith, Elias Haddad, Philip Lammers, Denise Oram, Taneem Amin, Bradford Harris, Megan Hoeksema, Hyun Hwang. Low dose aspirin that reduces mortality from lung adenocarcinoma inhibits both platelet COX-1 and the biosynthesis of PGE2. [abstract]. In: Proceedings of the Thirteenth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2014 Sep 27-Oct 1; New Orleans, LA. Philadelphia (PA): AACR; Can Prev Res 2015;8(10 Suppl): Abstract nr PR05.

Synthesis, biological activity screening and molecular modeling study of acylaminoacetamide derivatives

In this study, non-rigid analogs of thalidomide have been designed in order to develop potentially active, more effective and safer lead molecules for disorders caused or contributed by inflammation. Five different series of acylaminoacetamide compounds were synthesized, and the biological inhibitory potency of the title compounds has been determined by evaluating their effects on COX-2 isoenzyme expression and PGE2 production in A549 (human lung adenocarcinoma) cell lines. Among the studied series, N-[2-(isopropylamino)-2-oxoethyl]isonicotinamide is the most active inhibitory compound on COX-2 isoenzyme expression, and N-[2-oxo-2-(pyrolydine-1-yl)etyl]isonicotinamide is the most active inhibitory compound on the biosynthesis of PGE2. Molecular docking studies and molecular dynamics simulations were also applied to investigate non-covalent interactions of the most active compounds inside the active side of the crystal structure of murine cyclooxygenase 2 (mCOX-2) isoenzyme.