Chiral Me-2-arachidonoyl Glycerols: The First Potent Endocannabinoid Glyceride Templates with Stability to COX-2.

2-Arachidonoyl glycerol (2-AG) is the principal endogenously produced ligand for the cannabinoid CB1 and CB2 receptors (CBRs). The lack of potent and efficacious 2-AG ligands with resistance against metabolizing enzymes represents a significant void in the armamentarium of research tools available for studying eCB system molecular constituents and their function. Herein we report the first endocannabinoid glyceride templates with remarkably high potency and efficacy at CBRs. Two of our lead chiral 2-AG analogs, namely, (13S)- and (13R)-Me-2-AGs, potently inhibit excitatory neurotransmission via CB1 while they are endowed with excellent resistance to the oxidizing enzyme COX-2. Our SAR results are supported by docking studies of the key analog and 2-AG on the crystal structures of CB1.

Jedi-1/MEGF12-mediated phagocytosis controls the pro-neurogenic properties of microglia in the ventricular-subventricular zone.

Microglia are the primary phagocytes in the central nervous system and clear dead cells generated during development or disease. The phagocytic process shapes the microglia phenotype, which affects the local environment. A unique population of microglia resides in the ventricular-subventricular zone (V-SVZ) of neonatal mice, but how they influence the neurogenic niche is not well understood. Here, we demonstrate that phagocytosis contributes to a pro-neurogenic microglial phenotype in the V-SVZ and that these microglia phagocytose apoptotic cells via the engulfment receptor Jedi-1. Deletion of Jedi-1 decreases apoptotic cell clearance, triggering a neuroinflammatory microglia phenotype that resembles dysfunctional microglia in neurodegeneration and aging and that reduces neural precursor proliferation via elevated interleukin-1ß signaling; interleukin-1 receptor inhibition rescues precursor proliferation in vivo. Together, these results reveal a critical role for Jedi-1 in connecting microglial phagocytic activity to the maintenance of a pro-neurogenic phenotype in the developing V-SVZ.

Base-Displaced Intercalated Structure of the 3-(2-Deoxy-ß-D-erythropentofuranosyl)-pyrimido[1,2-f]purine-6,10(3H,5H)-dione (6-oxo-M1dG) Lesion in DNA.

The genotoxic 3-(2-deoxy-ß-D-erythro-pentofuranosyl)pyrimido[1,2-α]purin-10(3H)-one (M1dG) DNA lesion arises from endogenous exposures to base propenals generated by oxidative damage and from exposures to malondialdehyde (MDA), produced by lipid peroxidation. Once formed, M1dG may oxidize, in vivo, to 3-(2-deoxy-ß-D-erythropentofuranosyl)-pyrimido[1,2-f]purine-6,10(3H,5H)-dione (6-oxo-M1dG). The latter blocks DNA replication and is a substrate for error-prone mutagenic bypass by the Y-family DNA polymerase hpol η. To examine structural consequences of 6-oxo-M1dG damage in DNA, we conducted NMR studies of 6-oxo-M1dG incorporated site-specifically into 5' -d(C1A2T3X4A5T6G7A8C9G10C11T12)-3':5'-d(A13G14C15G16T17C18A19T20C21A22T23G24)-3' (X = 6-oxo-M1dG). NMR spectra afforded detailed resonance assignments. Chemical shift analyses revealed that nucleobase C21, complementary to 6-oxo-M1dG, was deshielded compared with the unmodified duplex. Sequential NOEs between 6-oxo-M1dG and A5 were disrupted, as well as NOEs between T20 and C21 in the complementary strand. The structure of the 6-oxo-M1dG modified DNA duplex was refined by using molecular dynamics (rMD) calculations restrained by NOE data. It revealed that 6-oxo-M1dG intercalated into the duplex and remained in the anti-conformation about the glycosyl bond. The complementary cytosine C21 extruded into the major groove, accommodating the intercalated 6-oxo-M1dG. The 6-oxo-M1dG H7 and H8 protons faced toward the major groove, while the 6-oxo-M1dG imidazole proton H2 faced into the major groove. Structural perturbations to dsDNA were limited to the 6-oxo-M1dG damaged base pair and the flanking T3:A22 and A5:T20 base pairs. Both neighboring base pairs remained within the Watson-Crick hydrogen bonding contact. The 6-oxo-M1dG did not stack well with the 5'-neighboring base pair T3:A22 but showed improved stacking with the 3'-neighboring base pair A5:T20. Overall, the base-displaced intercalated structure was consistent with thermal destabilization of the 6-oxo-M1dG damaged DNA duplex; thermal melting temperature data showed a 15 °C decrease in Tm compared to the unmodified duplex. The structural consequences of 6-oxo-M1dG formation in DNA are evaluated in the context of the chemical biology of this lesion.

The peroxidation-derived DNA adduct, 6-oxo-M1dG, is a strong block to replication by human DNA polymerase η.

The DNA adduct 6-oxo-M1dG, (3-(2'-deoxy-ß-D-erythro-pentofuranosyl)-6-oxo-pyrimido(1,2alpha)purin-10(3H)-one) is formed in the genome via oxidation of the peroxidation-derived adduct M1dG. However, the effect of 6-oxo-M1dG adducts on subsequent DNA replication is unclear. Here we investigated the ability of the human Y-family polymerase hPol η to bypass 6-oxo-M1dG. Using steady-state kinetics and analysis of DNA extension products by liquid chromatography-tandem mass spectrometry, we found hPol η preferentially inserts a dAMP or dGMP nucleotide into primer-templates across from the 6-oxo-M1dG adduct, with dGMP being slightly preferred. We also show primer-templates with a 3'-terminal dGMP or dAMP across from 6-oxo-M1dG were extended to a greater degree than primers with a dCMP or dTMP across from the adduct. In addition, we explored the structural basis for bypass of 6-oxo-M1dG by hPol η using X-ray crystallography of both an insertion-stage and an extension-stage complex. In the insertion-stage complex, we observed that the incoming dCTP opposite 6-oxo-M1dG, although present during crystallization, was not present in the active site. We found the adduct does not interact with residues in the hPol η active site but rather forms stacking interactions with the base pair immediately 3' to the adduct. In the extension-stage complex, we observed the 3' hydroxyl group of the primer strand dGMP across from 6-oxo-M1dG is not positioned correctly to form a phosphodiester bond with the incoming dCTP. Taken together, these results indicate 6-oxo-M1dG forms a strong block to DNA replication by hPol η and provide a structural basis for its blocking ability.

Development of Pluoronic nanoparticles of fluorocoxib A for endoscopic fluorescence imaging of colonic adenomas.

Significance: Current white light colonoscopy suffers from many limitations that allow 22% to 32% of preneoplastic lesions to remain undetected. This high number of false negatives contributes to the appearance of interval malignancies, defined as neoplasms diagnosed between screening colonoscopies at a rate of 2% to 6%. Aim: The shortcomings of today's white light-based colorectal cancer screening are addressed by colonoscopic fluorescence imaging of preneoplastic lesions using targeted fluorescent agents to enhance contrast between the lesion and the surrounding normal colonic epithelium. Approach: We describe the development of Pluronic® nanoparticles of fluorocoxib A (FA), a fluorescent cyclooxygenase-2 (COX-2) inhibitor that enables targeted imaging of inflammation and cancer in numerous animal models, for endoscopic florescence imaging of colonic adenomas. Results: We formulated FA, a fluorescent COX-2 inhibitor, or fluorocoxib negative control (FNC), a nontargeted fluorophore and a negative control for FA, in micellar nanoparticles of FDA approved Pluronic tri-block co-polymer using a bulk solvent evaporation method. This afforded FA-loaded micellar nanoparticles (FA-NPs) or FNC-loaded micellar nanoparticles (FNC-NPs) with the hydrodynamic diameters ( D h ) of 45.7 ± 2.5 nm and 44.9 ± 3.8 nm and the zeta potentials ( ζ ) of - 1.47 ± 0.3 mV and - 1.64 ± 0.5 mV , respectively. We intravenously injected B6;129 mice bearing colonic adenomas induced by azoxymethane and dextran-sodium sulfate with FA-loaded Pluronic nanoparticles (FA-NPs). The diffusion-mediated local FA release and its binding to COX-2 enzyme allowed for clear detection of adenomas with high signal-to-noise ratios. The COX-2 targeted delivery and tumor retention were validated by negligible tumor fluorescence detected upon colonoscopic imaging of adenoma-bearing mice injected with Pluronic nanoparticles of FNC or of animals predosed with the COX-2 inhibitor, celecoxib, followed by intravenous dosing of FA-NPs. Conclusions: These results demonstrate that the formulation of FA in Pluronic nanoparticles overcomes a significant hurdle to its clinical development for early detection of colorectal neoplasms by fluorescence endoscopy.

Jedi-1/MEGF12-mediated phagocytosis controls the pro-neurogenic properties of microglia in the ventricular-subventricular zone.

Microglia are the primary phagocytes in the central nervous system and are responsible for clearing dead cells generated during development or disease. The phagocytic process shapes the phenotype of the microglia, which affects the local environment. A unique population of microglia reside in the ventricular-subventricular zone (V-SVZ) of neonatal mice, but how they influence this neurogenic niche is not well-understood. Here, we demonstrate that phagocytosis creates a pro-neurogenic microglial phenotype in the V-SVZ and that these microglia phagocytose apoptotic cells via the engulfment receptor Jedi-1. Deletion of Jedi-1 decreases apoptotic cell clearance, triggering the development of a neuroinflammatory phenotype, reminiscent of neurodegenerative and-age-associated microglia, that reduces neural precursor proliferation via elevated interleukin (IL)-1ß signaling; inhibition of IL-1 receptor rescues precursor proliferation in vivo. Together, these results reveal a critical role for Jedi-1 in connecting microglial phagocytic activity to a phenotype that promotes neurogenesis in the developing V-SVZ.

Ferroptosis Inhibitors Suppress Prostaglandin Synthesis in Lipopolysaccharide-Stimulated Macrophages.

Necrostatin-1 blocks ferroptosis via an unknown mechanism and necroptosis through inhibition of receptor-interacting protein kinase-1 (RIP1). We report that necrostatin-1 suppresses cyclooxygenase-2-dependent prostaglandin biosynthesis in lipopolysaccharide-treated RAW264.7 macrophages (IC50 ∼ 100 µM). This activity is shared by necrostatin-1i (IC50 ∼ 50 µM), which lacks RIP1 inhibitory activity, but not the RIP1 inhibitors necrostatin-1s or deschloronecrostatin-1s. Furthermore, we show that the potent ferroptosis inhibitors and related compounds ferrostatin-1, phenoxazine, phenothiazine, and 10-methylphenothiazine strongly inhibit cellular prostaglandin biosynthesis with IC50's in the range of 30 nM to 3.5 µM. None of the compounds inhibit lipopolysaccharide-mediated cyclooxygenase-2 protein induction. In the presence of activating hydroperoxides, the necrostatins and ferroptosis inhibitors range from low potency inhibition to stimulation of in vitro cyclooxygenase-2 activity; however, inhibitory potency is increased under conditions of low peroxide tone. The ferroptosis inhibitors are highly effective reducing substrates for cyclooxygenase-2's peroxidase activity, suggesting that they act by suppressing hydroperoxide-mediated activation of the cyclooxygenase active site. In contrast, for the necrostatins, cellular prostaglandin synthesis inhibition does not correlate with peroxidase-reducing activity but rather with the presence of a thiohydantoin substituent, which conveys the ability to reduce the endoperoxide intermediate prostaglandin H2 to prostaglandin F2α in vitro. This finding suggests that necrostatin-1 blocks cellular prostaglandin synthesis and ferroptosis via a redox mechanism distinct from action as a one-electron donor. The results indicate that a wide range of compounds derived from redox-active chemical scaffolds can block cellular prostaglandin biosynthesis.

The Endocannabinoid 2-Arachidonoylglycerol Bidirectionally Modulates Acute and Protracted Effects of Predator Odor Exposure.

BACKGROUND: Stress-related disorders are among the most prevalent psychiatric disorders, characterized by excess fear and enhanced avoidance of trauma triggers. Elucidating the mechanisms regulating temporally distinct aspects of innate and conditioned fear responses could facilitate novel therapeutic development for stress-related disorders. One potential target that has recently emerged is the endocannabinoid system, which has been reported to mediate the physiological response to stress and represents an important substrate underlying individual differences in stress susceptibility. METHODS: Here, we exposed male and female CD-1 mice to an innate predator stressor, 2MT (2-methyl-2-thiazoline), to investigate the ability of endocannabinoid signaling to modulate temporally distinct innate and conditioned fear behaviors. RESULTS: We found that 2MT exposure increased amygdala 2-AG (2-arachidonoylglycerol) content and selectively increased excitability in central, but not basolateral, amygdala neurons. We also found that pharmacological 2-AG augmentation during stress exposure exacerbated both acute freezing responses and central amygdala hyperexcitability via cannabinoid receptor type 1- and type 2-dependent mechanisms. Finally, 2-AG augmentation during stress exposure reduced long-term contextual conditioned freezing, and 2-AG augmentation 24 hours after stress exposure reduced conditioned avoidance behavior. CONCLUSIONS: Our findings demonstrate a bidirectional effect of 2-AG augmentation on innate and conditioned fear behavior, with enhancement of 2-AG levels during stress promoting innate fear responses but ultimately resulting in long-term conditioned fear reduction. These data could reconcile contradictory data on the role of 2-AG in the regulation of innate and conditioned fear-related behavioral responses.

Discovery of a Redox-Activatable Chemical Probe for Detection of Cyclooxygenase-2 in Cells and Animals.

Cyclooxygenase-2 (COX-2) expression is up-regulated in inflammatory tissues and many premalignant and malignant tumors. Assessment of COX-2 protein in vivo, therefore, promises to be a powerful strategy to distinguish pathologic cells from normal cells in a complex disease setting. Herein, we report the first redox-activatable COX-2 probe, fluorocoxib Q (FQ), for in vivo molecular imaging of pathogenesis. FQ inhibits COX-2 selectively in purified enzyme and cell-based assays. FQ exhibits extremely low fluorescence and displays time- and concentration-dependent fluorescence enhancement upon exposure to a redox environment. FQ enters the cells freely and binds to the COX-2 enzyme. FQ exhibits high circulation half-life and metabolic stability sufficient for target site accumulation and demonstrates COX-2-targeted uptake and retention in cancer cells and pathologic tissues. Once taken up, it undergoes redox-mediated transformation into a fluorescent compound fluorocoxib Q-H that results in high signal-to-noise contrast and differentiates pathologic tissues from non-pathologic tissues for real-time in vivo imaging.

Impact of cyclooxygenase-2 inhibition on cannabis withdrawal and circulating endocannabinoids in daily cannabis smokers.

Attenuating enzymatic degradation of endocannabinoids (eCBs) by fatty acid amide hydrolase (FAAH) reduces cannabis withdrawal symptoms in preclinical and clinical studies. In mice, blocking cyclooxygenase-2 (COX-2) activity increases central eCB levels by inhibiting fatty acid degradation. This placebo-controlled study examined the effects of the FDA-approved COX-2 selective inhibitor, celecoxib, on cannabis withdrawal, 'relapse', and circulating eCBs in a human laboratory model of cannabis use disorder. Daily, nontreatment-seeking cannabis smokers (12M, 3F) completed a crossover study comprising two 11-day study phases (separated by >14 days for medication clearance). In each phase, the effects of daily BID placebo (0 mg) or celecoxib (200 mg) on cannabis (5.3% THC) intoxication, withdrawal symptoms (4 days of inactive cannabis self-administration) and 'relapse' (3 days of active cannabis self-administration following abstinence) were assessed. Outcome measures included mood, cannabis self-administration, sleep, food intake, cognitive performance, tobacco cigarette use and circulating eCBs and related lipids. Under placebo maintenance, cannabis abstinence produced characteristic withdrawal symptoms (negative mood, anorexia and dreaming) relative to cannabis administration and was associated with increased OEA (a substrate of FAAH) and oleic acid (metabolite of OEA), with no change in eCB levels. Compared to placebo, celecoxib improved subjective (but not objective) measures of sleep and did not affect mood or plasma levels of eCBs or associated lipids and increased cannabis craving. The overall absence of effects on cannabis withdrawal symptoms, self-administration or circulating eCBs relative to placebo, combined with an increase in cannabis craving, suggests celecoxib does not show promise as a potential pharmacotherapy for CUD.

Enhancing endocannabinoid signalling in astrocytes promotes recovery from traumatic brain injury.

Traumatic brain injury is an important risk factor for development of Alzheimer's disease and dementia. Unfortunately, no effective therapies are currently available for prevention and treatment of the traumatic brain injury-induced Alzheimer's disease-like neurodegenerative disease. This is largely due to our limited understanding of the mechanisms underlying traumatic brain injury-induced neuropathology. Previous studies showed that pharmacological inhibition of monoacylglycerol lipase, a key enzyme degrading the endocannabinoid 2-arachidonoylglycerol, attenuates traumatic brain injury-induced neuropathology. However, the mechanism responsible for the neuroprotective effects produced by inhibition of monoacylglycerol lipase in traumatic brain injury remains unclear. Here we first show that genetic deletion of monoacylglycerol lipase reduces neuropathology and averts synaptic and cognitive declines in mice exposed to repeated mild closed head injury. Surprisingly, these neuroprotective effects result primarily from inhibition of 2-arachidonoylglycerol metabolism in astrocytes, rather than in neurons. Single-cell RNA-sequencing data reveal that astrocytic monoacylglycerol lipase knockout mice display greater resilience to traumatic brain injury-induced changes in expression of genes associated with inflammation or maintenance of brain homeostasis in astrocytes and microglia. The monoacylglycerol lipase inactivation-produced neuroprotection is abrogated by deletion of the cannabinoid receptor-1 or by adeno-associated virus vector-mediated silencing of astrocytic peroxisome proliferator-activated receptor-γ. This is further supported by the fact that overexpression of peroxisome proliferator-activated receptor-γ in astrocytes prevents traumatic brain injury-induced neuropathology and impairments in spatial learning and memory. Our results reveal a previously undefined cell type-specific role of 2-arachidonoylglycerol metabolism and signalling pathways in traumatic brain injury-induced neuropathology, suggesting that enhanced 2-arachidonoylglycerol signalling in astrocytes is responsible for the monoacylglycerol lipase inactivation-produced alleviation of neuropathology and deficits in synaptic and cognitive functions in traumatic brain injury.

Mapping the Binding Sites of UDP and Prostaglandin E2 Glyceryl Ester in the Nucleotide Receptor P2Y6.

Cyclooxygenase-2 catalyzes the biosynthesis of prostaglandins from arachidonic acid and the biosynthesis of prostaglandin glycerol esters (PG-Gs) from 2-arachidonoylglycerol. PG-Gs are mediators of several biological actions such as macrophage activation, hyperalgesia, synaptic plasticity, and intraocular pressure. Recently, the human UDP receptor P2Y6 was identified as a target for the prostaglandin E2 glycerol ester (PGE2 -G). Here, we show that UDP and PGE2 -G are evolutionary conserved endogenous agonists at vertebrate P2Y6 orthologs. Using sequence comparison of P2Y6 orthologs, homology modeling, and ligand docking studies, we proposed several receptor positions participating in agonist binding. Site-directed mutagenesis and functional analysis of these P2Y6 mutants revealed that both UDP and PGE2 -G share in parts one ligand-binding site. Thus, the convergent signaling of these two chemically very different agonists has already been manifested in the evolutionary design of the ligand-binding pocket.

Aminopyridine analogs selectively target metastatic pancreatic cancer.

Metastatic outgrowth is supported by metabolic adaptations that may differ from the primary tumor of origin. However, it is unknown if such adaptations are therapeutically actionable. Here we report a novel aminopyridine compound that targets a unique Phosphogluconate Dehydrogenase (PGD)-dependent metabolic adaptation in distant metastases from pancreatic cancer patients. Compared to structurally similar analogs, 6-aminopicolamine (6AP) potently and selectively reversed PGD-dependent metastatic properties, including intrinsic tumorigenic capacity, excess glucose consumption, and global histone hyperacetylation. 6AP acted as a water-soluble prodrug that was converted into intracellular bioactive metabolites that inhibited PGD in vitro, and 6AP monotherapy demonstrated anti-metastatic efficacy with minimal toxicity in vivo. Collectively, these studies identify 6AP and possibly other 6-aminopyridines as well-tolerated prodrugs with selectivity for metastatic pancreatic cancers. If unique metabolic adaptations are a common feature of metastatic or otherwise aggressive human malignancies, then such dependencies could provide a largely untapped pool of druggable targets for patients with advanced cancers.

Site-Specific Synthesis of Oligonucleotides Containing 6-Oxo-M1dG, the Genomic Metabolite of M1dG, and Liquid Chromatography-Tandem Mass Spectrometry Analysis of Its In Vitro Bypass by Human Polymerase ι.

The lipid peroxidation product malondialdehyde and the DNA peroxidation product base-propenal react with dG to generate the exocyclic adduct, M1dG. This mutagenic lesion has been found in human genomic and mitochondrial DNA. M1dG in genomic DNA is enzymatically oxidized to 6-oxo-M1dG, a lesion of currently unknown mutagenic potential. Here, we report the synthesis of an oligonucleotide containing 6-oxo-M1dG and the results of extension experiments aimed at determining the effect of the 6-oxo-M1dG lesion on the activity of human polymerase iota (hPol ι). For this purpose, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay was developed to obtain reliable quantitative data on the utilization of poorly incorporated nucleotides. Results demonstrate that hPol ι primarily incorporates deoxycytidine triphosphate (dCTP) and thymidine triphosphate (dTTP) across from 6-oxo-M1dG with approximately equal efficiency, whereas deoxyadenosine triphosphate (dATP) and deoxyguanosine triphosphate (dGTP) are poor substrates. Following the incorporation of a single nucleotide opposite the lesion, 6-oxo-M1dG blocks further replication by the enzyme.

In vivo endocannabinoid dynamics at the timescale of physiological and pathological neural activity.

The brain's endocannabinoid system is a powerful controller of neurotransmitter release, shaping synaptic communication under physiological and pathological conditions. However, our understanding of endocannabinoid signaling in vivo is limited by the inability to measure their changes at timescales commensurate with the high lability of lipid signals, leaving fundamental questions of whether, how, and which endocannabinoids fluctuate with neural activity unresolved. Using novel imaging approaches in awake behaving mice, we now demonstrate that the endocannabinoid 2-arachidonoylglycerol, not anandamide, is dynamically coupled to hippocampal neural activity with high spatiotemporal specificity. Furthermore, we show that seizures amplify the physiological endocannabinoid increase by orders of magnitude and drive the downstream synthesis of vasoactive prostaglandins that culminate in a prolonged stroke-like event. These results shed new light on normal and pathological endocannabinoid signaling in vivo.

Targeting diacylglycerol lipase reduces alcohol consumption in preclinical models.

Alcohol use disorder (AUD) is associated with substantial morbidity, mortality, and societal cost, and pharmacological treatment options for AUD are limited. The endogenous cannabinoid (eCB) signaling system is critically involved in reward processing and alcohol intake is positively correlated with release of the eCB ligand 2-Arachidonoylglycerol (2-AG) within reward neurocircuitry. Here we show that genetic and pharmacological inhibition of diacylglycerol lipase (DAGL), the rate limiting enzyme in the synthesis of 2-AG, reduces alcohol consumption in a variety of preclinical models ranging from a voluntary free-access model to aversion resistant-drinking and dependence-like drinking induced via chronic intermittent ethanol vapor exposure in mice. DAGL inhibition during either chronic alcohol consumption or protracted withdrawal was devoid of anxiogenic and depressive-like behavioral effects. Lastly, DAGL inhibition also prevented ethanol-induced suppression of GABAergic transmission onto midbrain dopamine neurons, providing mechanistic insight into how DAGL inhibition could affect alcohol reward. These data suggest reducing 2-AG signaling via inhibition of DAGL could represent an effective approach to reduce alcohol consumption across the spectrum of AUD severity.

Naproxen chemoprevention promotes immune activation in Lynch syndrome colorectal mucosa.

OBJECTIVE: Patients with Lynch syndrome (LS) are at markedly increased risk for colorectal cancer. It is being increasingly recognised that the immune system plays an essential role in LS tumour development, thus making an ideal target for cancer prevention. Our objective was to evaluate the safety, assess the activity and discover novel molecular pathways involved in the activity of naproxen as primary and secondary chemoprevention in patients with LS. DESIGN: We conducted a Phase Ib, placebo-controlled, randomised clinical trial of two dose levels of naproxen sodium (440 and 220 mg) administered daily for 6 months to 80 participants with LS, and a co-clinical trial using a genetically engineered mouse model of LS and patient-derived organoids (PDOs). RESULTS: Overall, the total number of adverse events was not different across treatment arms with excellent tolerance of the intervention. The level of prostaglandin E2 in the colorectal mucosa was significantly decreased after treatment with naproxen when compared with placebo. Naproxen activated different resident immune cell types without any increase in lymphoid cellularity, and changed the expression patterns of the intestinal crypt towards epithelial differentiation and stem cell regulation. Naproxen demonstrated robust chemopreventive activity in a mouse co-clinical trial and gene expression profiles induced by naproxen in humans showed perfect discrimination of mice specimens with LS and PDOs treated with naproxen and control. CONCLUSIONS: Naproxen is a promising strategy for immune interception in LS. We have discovered naproxen-induced gene expression profiles for their potential use as predictive biomarkers of drug activity. TRIAL REGISTRATION NUMBER: gov Identifier: NCT02052908.

Targeted Detection of Cyclooxygenase-1 in Ovarian Cancer.

Overexpression of cyclooxygenase-1 (COX-1) is associated with the initiation and progression of ovarian cancer, and targeted imaging of COX-1 is a promising strategy for early detection of this disease. We report the discovery of N-[(5-carboxy-X-rhodaminyl)but-4-yl]-3-(1-(4-methoxyphenyl)-5-(p-tolyl)-1H-pyrazol-3-yl)propenamide (CMP) as the first COX-1-targeted optical agent for imaging of ovarian cancer. CMP exhibits light emission at 604 nm (λmax), thereby minimizing tissue autofluorescence interference. In both purified enzyme and COX-1-expressing human ovarian adenocarcinoma (OVCAR-3) cells, CMP inhibits COX-1 at low nanomolar potencies (IC50 = 94 and 44 nM, respectively). CMP's selective binding to COX-1 in OVCAR-3 cells was visualized microscopically as intense intracellular fluorescence. In vivo optical imaging of xenografts in athymic nude mice revealed COX-1-dependent accumulation of CMP in COX-1-expressing mouse ovarian surface epithelial carcinoma (ID8-NGL) and OVCAR-3 cells. These results establish proof-of-principle for the feasibility of targeting COX-1 in the development of new imaging and therapeutic strategies for ovarian cancer.

Molecular Imaging of Inflammation in Osteoarthritis Using a Water-Soluble Fluorocoxib.

Clinical imaging approaches to detect inflammatory biomarkers, such as cyclooxygenase-2 (COX-2), may facilitate the diagnosis and therapy of inflammatory diseases. To this end, we report the discovery of N-[(rhodamin-X-yl)but-4-yl]-2-[1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indol-3-yl]acetamide chloride salt (fluorocoxib D), a hydrophilic analog of fluorocoxib A. Fluorocoxib D inhibits COX-2 selectively in purified enzyme preparations and cells. It exhibits adequate photophysical properties to enable detection of COX-2 in intact cells, in a mouse model of carrageenan-induced acute footpad inflammation and inflammation in a mouse model of osteoarthritis. COX-2-selectivity was verified either by blocking the enzyme's active site with celecoxib or by molecular imaging with nontargeted 5-carboxy-X-rhodamine dye. These data indicate that fluorocoxib D is an ideal candidate for early detection of inflammatory or neoplastic lesions expressing elevated levels of COX-2.

Harmaline Analogs as Substrate-Selective Cyclooxygenase-2 Inhibitors.

We report the design, synthesis, and evaluation of a series of harmaline analogs as selective inhibitors of 2-arachidonylglycerol (2-AG) oxygenation over arachidonic acid (AA) oxygenation by purified cyclooxygenase-2 (COX-2). A fused tricyclic harmaline analog containing a CH3O substituent at C-6 and a CH3 group at the C-1 position of 4,9-dihydro-3H-pyrido[3,4-b]indole (compound 3) was the best substrate-selective COX-2 inhibitor of those evaluated, exhibiting a 2AG-selective COX-2 inhibitory IC50 of 0.022 µM as compared to >1 µM for AA. The 2.66 Å resolution crystal complex of COX-2 with compound 3 revealed that this series of tricyclic indoles binds in the cyclooxygenase channel by flipping the side chain of L531 toward the dimer interface. This novel tricyclic indole series provides the foundation for the development of promising substrate-selective molecules capable of increasing endocannabinoid (EC) levels in the brain to offer new treatments for a variety of diseases, from pain and inflammation to stress and anxiety disorders.