Inhibition of 5-lipoxygenase by MK886 augments the antitumor activity of celecoxib in human colon cancer cells

Transcriptomic Analysis of Arachidonic Acid Pathway Genes Provides Mechanistic Insight into Multi-Organ Inflammatory and Vascular Diseases

Arachidonic acid (AA) metabolites have been associated with several diseases across various organ systems, including the cardiovascular, pulmonary, and renal systems. Lipid mediators generated from AA oxidation have been studied to control macrophages, T-cells, cytokines, and fibroblasts, and regulate inflammatory mediators that induce vascular remodeling and dysfunction. AA is metabolized by cyclooxygenase (COX), lipoxygenase (LOX), and cytochrome P450 (CYP) to generate anti-inflammatory, pro-inflammatory, and pro-resolutory oxidized lipids. As comorbid states such as diabetes, hypertension, and obesity become more prevalent in cardiovascular disease, studying the expression of AA pathway genes and their association with these diseases can provide unique pathophysiological insights. In addition, the AA pathway of oxidized lipids exhibits diverse functions across different organ systems, where a lipid can be both anti-inflammatory and pro-inflammatory depending on the location of metabolic activity. Therefore, we aimed to characterize the gene expression of these lipid enzymes and receptors throughout multi-organ diseases via a transcriptomic meta-analysis using the Gene Expression Omnibus (GEO) Database. In our study, we found that distinct AA pathways were expressed in various comorbid conditions, especially those with prominent inflammatory risk factors. Comorbidities, such as hypertension, diabetes, and obesity appeared to contribute to elevated expression of pro-inflammatory lipid mediator genes. Our results demonstrate that expression of inflammatory AA pathway genes may potentiate and attenuate disease; therefore, we suggest further exploration of these pathways as therapeutic targets to improve outcomes.

A Method for the Synthesis of Thioindoles through Copper-Catalyzed C-S Bond Coupling Reaction

We herein report the copper-catalyzed C-S bond coupling reaction of indoles with N-thiosuccinimides, resulting in moderate to excellent yields of mono- and bis-sulfenylated compounds such as arylthioindoles, alkylthioindoles, selenylated indoles, and cysteine-substituted indoles. Thioarylation and thioglycosylation at the C2 position of indole alkaloids in the Radix Isatidis were achieved via structural modification. The first total syntheses of isatindigotindolosides III and IV have been successfully carried out. The electrophilic sulfenyl bromides generated in situ can play an important role in the catalytic cycle.

Arachidonic acid metabolism in health and disease

Arachidonic acid (AA), an n-6 essential fatty acid, is a major component of mammalian cells and can be released by phospholipase A2. Accumulating evidence indicates that AA plays essential biochemical roles, as it is the direct precursor of bioactive lipid metabolites of eicosanoids such as prostaglandins, leukotrienes, and epoxyeicosatrienoic acid obtained from three distinct enzymatic metabolic pathways: the cyclooxygenase pathway, lipoxygenase pathway, and cytochrome P450 pathway. AA metabolism is involved not only in cell differentiation, tissue development, and organ function but also in the progression of diseases, such as hepatic fibrosis, neurodegeneration, obesity, diabetes, and cancers. These eicosanoids are generally considered proinflammatory molecules, as they can trigger oxidative stress and stimulate the immune response. Therefore, interventions in AA metabolic pathways are effective ways to manage inflammatory-related diseases in the clinic. Currently, inhibitors targeting enzymes related to AA metabolic pathways are an important area of drug discovery. Moreover, many advances have also been made in clinical studies of AA metabolic inhibitors in combination with chemotherapy and immunotherapy. Herein, we review the discovery of AA and focus on AA metabolism in relation to health and diseases. Furthermore, inhibitors targeting AA metabolism are summarized, and potential clinical applications are discussed.

Prognostic, Immunological, and Mutational Analysis of MTA2 in Pan-Cancer and Drug Screening for Hepatocellular Carcinoma

BACKGROUND

Metastasis-associated protein 2 (MTA2) is a member of the metastasis-associated transcriptional regulator family and is a core component of the nucleosome remodeling and histone deacetylation complex. Despite growing evidence that MTA2 plays a crucial role in the tumorigenesis of certain cancers, no systematic pan-cancer analysis of MTA2 is available to date. Therefore, the aim of our study is to explore the prognostic value of MTA2 in 33 cancer types and to investigate its potential immune function.

METHODS

by comprehensive use of databases from TCGA, GTEx, GEO, UCSC xena, cBioPortal, comPPI, GeneMANIA, TCIA, MSigDB, and PDB, we applied various bioinformatics approaches to investigate the potential role of MTA2, including analyzing the association of MTA2 with MSI, prognosis, gene mutation, and immune cell infiltration in different tumors. We constructed a nomogram in TCGA-LIHC, performed single-cell sequencing (scRNA-seq) analysis of MTA2 in hepatocellular carcinoma (HCC), and screened drugs for the treatment of HCC. Finally, immunohistochemical experiments were performed to verify the expression and prognostic value of MTA2 in HCC. In vitro experiments were employed to observe the growth inhibition effects of MK-886 on the HCC cell line HepG2.

RESULTS

The results suggested that MTA2 was highly expressed in most cancers, and MTA2 expression was associated with the prognosis of different cancers. In addition, MTA2 expression was associated with Tumor Mutation Burden (TMB) in 12 cancer types and MSI in 8 cancer types. Immunoassays indicated that MTA2 positively correlated with activated memory CD4 T cells and M0 macrophage infiltration levels in HCC. ScRNA-seq analysis based on the GEO dataset discovered that MTA2 was significantly expressed in T cells in HCC. Finally, the eXtreme Sum (Xsum) algorithm was used to screen the antitumor drug MK-886, and the molecular docking technique was utilized to reveal the binding capacity between MK-886 and the MTA2 protein. The results demonstrated excellent binding sites between them, which bind to each other through Π-alkyl and alkyl interaction forces. An immunohistochemistry experiment showed that MTA2 protein was highly expressed in HCC, and high MTA2 expression was associated with poor survival in HCC patients. MK-886 significantly inhibited the proliferation and induced cell death of HepG2 cells in a dose-dependent manner.

CONCLUSIONS

Our study demonstrated that MTA2 plays crucial roles in tumor progression and tumor immunity, and it could be used as a prognostic marker for various malignancies. MK-886 might be a powerful drug for HCC.

Combining gamma-tocopherol and aspirin synergistically suppresses colitis-associated colon tumorigenesis and modulates the gut microbiota in mice, and inhibits the growth of human colon cancer cells

Despite being shown to be effective for chemoprevention of colorectal cancer, aspirin has limitations including adverse effects and inability to block colitis-associated colon cancer (CAC). γ-Tocopherol (γT), a vitamin E form, has been reported to mitigate experimental colitis and CAC, prolong the anti-inflammatory activity of aspirin and alleviate aspirin-induced adverse effect. We therefore hypothesize that combining γT and aspirin is better than either compound singly for suppressing CAC. This hypothesis was tested in the murine azoxymethane (AOM)/dextran sodium sulfate (DSS)-induced CAC model and with human HCT116 colon cancer cells. Compared to the control, combining aspirin (250 ppm) and γT (500 ppm) but not either compound alone significantly reduced AOM/DSS-induced tumor area and multiplicity of large-size tumors by 60% and 50%, respectively. Meanwhile, γT mitigated aspirin-promoted inflammation and stomach lesions in mice. Moreover, the combination appeared to cause favorable changes of gut microbiota compared to the control and synergistically suppressed the growth of HCT116 cells. Our study demonstrates that combining aspirin and γT improves anticancer effects and counteracts side effects compared to aspirin and may therefore be a novel combinatory chemopreventive agent against CAC.

Synthesis of 3-Haloindoles via Cascade Oxidative Cyclization/Halogenation of 2-Alkenylanilines Mediated by PIDA and LiBr/KI

The treatment of 2-alkenylanilines with phenyliodine(III) diacetate (PIDA) and LiBr or KI in HFIP was found to afford the corresponding 3-haloindoles via cascade oxidative cyclization/halogenation encompassing oxidative C-N/C-X (X = Br, I) bond formations. A plausible mechanism involving the in situ formation of the reactive AcO-X (X = Br, I) from the reaction of PIDA and LiBr/KI was postulated.

MDACT: A New Principle of Adjunctive Cancer Treatment Using Combinations of Multiple Repurposed Drugs, with an Example Regimen

In part one of this two-part paper, we present eight principles that we believe must be considered for more effective treatment of the currently incurable cancers. These are addressed by multidrug adjunctive cancer treatment (MDACT), which uses multiple repurposed non-oncology drugs, not primarily to kill malignant cells, but rather to reduce the malignant cells' growth drives. Previous multidrug regimens have used MDACT principles, e.g., the CUSP9v3 glioblastoma treatment. MDACT is an amalgam of (1) the principle that to be effective in stopping a chain of events leading to an undesired outcome, one must break more than one link; (2) the principle of Palmer et al. of achieving fractional cancer cell killing via multiple drugs with independent mechanisms of action; (3) the principle of shaping versus decisive operations, both being required for successful cancer treatment; (4) an idea adapted from Chow et al., of using multiple cytotoxic medicines at low doses; (5) the idea behind CUSP9v3, using many non-oncology CNS-penetrant drugs from general medical practice, repurposed to block tumor survival paths; (6) the concept from chess that every move creates weaknesses and strengths; (7) the principle of mass-by adding force to a given effort, the chances of achieving the goal increase; and (8) the principle of blocking parallel signaling pathways. Part two gives an example MDACT regimen, gMDACT, which uses six repurposed drugs-celecoxib, dapsone, disulfiram, itraconazole, pyrimethamine, and telmisartan-to interfere with growth-driving elements common to cholangiocarcinoma, colon adenocarcinoma, glioblastoma, and non-small-cell lung cancer. gMDACT is another example of-not a replacement for-previous multidrug regimens already in clinical use, such as CUSP9v3. MDACT regimens are designed as adjuvants to be used with cytotoxic drugs.

Urinary 8-iso PGF2α and 2,3-dinor-8-iso PGF2α can be indexes of colitis-associated colorectal cancer in mice

Early diagnosis of colorectal cancer is needed to reduce the mortal consequence by cancer. Lipid mediators play critical role in progression of colitis and colitis-associated colon cancer (CAC) and some of their metabolites are excreted in urine. Here, we attempted to find novel biomarkers in urinary lipid metabolite of a murine model of CAC. Mice were received single administration of azoxymethane (AOM) and repeated administration of dextran sulfate sodium (DSS). Lipid metabolites in their urine was measured by liquid chromatography mass spectrometry and their colon was collected to perform morphological study. AOM and DSS caused inflammation and tumor formation in mouse colon. Liquid chromatography mass spectrometry-based comprehensive analysis of lipid metabolites showed that cyclooxygenase-mediated arachidonic acid (AA) metabolites, prostaglandins, and reactive oxygen species (ROS)-mediated AA metabolites, isoprostanes, were predominantly increased in the urine of tumor-bearing mice. Among that, urinary prostaglandin (PG)E2 metabolite tetranor-PGEM and PGD2 metabolite tetranor-PGDM were significantly increased in both of urine collected at the acute phase of colitis and the carcinogenesis phase. On the other hand, two F2 isoprostanes (F2-IsoPs), 8-iso PGF2α and 2,3-dinor-8-iso PGF2α, were significantly increased only in the carcinogenesis phase. Morphological study showed that infiltrated monocytes into tumor mass strongly expressed ROS generator NADPH (p22phox). These observations suggest that urinary 8-iso PGF2α and 2,3-dinor-8-iso PGF2α can be indexes of CAC.

Non-Steroidal Anti-Inflammatory Drugs Increase Cisplatin, Paclitaxel, and Doxorubicin Efficacy against Human Cervix Cancer Cells

This study shows that the non-steroidal anti-inflammatory drug (NSAID) celecoxib and its non-cyclooxygenase-2 (COX2) analogue dimethylcelecoxib (DMC) exert a potent inhibitory effect on the growth of human cervix HeLa multi-cellular tumor spheroids (MCTS) when added either at the beginning (“preventive protocol”; IC₅₀ = 1 ± 0.3 nM for celecoxib and 10 ± 2 nM for DMC) or after spheroid formation (“curative protocol”; IC₅₀ = 7.5 ± 2 µM for celecoxib and 32 ± 10 µM for DMC). These NSAID IC₅₀ values were significantly lower than those attained in bidimensional HeLa cells (IC₅₀ = 55 ± 9 µM celecoxib and 48 ± 2 µM DMC) and bidimensional non-cancer cell cultures (3T3 fibroblasts and MCF-10A mammary gland cells with IC₅₀ from 69 to >100 µM, after 24 h). The copper-based drug casiopeina II-gly showed similar potency against HeLa MCTS. Synergism analysis showed that celecoxib, DMC, and casiopeinaII-gly at sub-IC₅₀ doses increased the potency of cisplatin, paclitaxel, and doxorubicin to hinder HeLa cell proliferation through a significant abolishment of oxidative phosphorylation in bidimensional cultures, with no apparent effect on non-cancer cells (therapeutic index >3.6). Similar results were attained with bidimensional human cervix cancer SiHa and human glioblastoma U373 cell cultures. In HeLa MCTS, celecoxib, DMC and casiopeina II-gly increased cisplatin toxicity by 41–85%. These observations indicated that celecoxib and DMC used as adjuvant therapy in combination with canonical anti-cancer drugs may provide more effective alternatives for cancer treatment.

A site-moiety map and virtual screening approach for discovery of novel 5-LOX inhibitors

The immune system works in conjunction with inflammation. Excessive inflammation underlies various human diseases, such as asthma, diabetes and heart disease. Previous studies found that 5-lipoxygenase (5-LOX) plays a crucial role in metabolizing arachidonic acid into inflammatory mediators and is a potential therapeutic target. In this study, we performed an in silico approach to establish a site-moiety map (SiMMap) to screen for new 5-LOX inhibitors. The map is composed of several anchors that contain key residues, moiety preferences, and their interaction types (i.e., electrostatic (E), hydrogen-bonding (H), and van der Waals (V) interactions) within the catalytic site. In total, we identified one EH, one H, and five V anchors, within the 5-LOX catalytic site. Based on the SiMMap, three 5-LOX inhibitors (YS1, YS2, and YS3) were identified. An enzyme-based assay validated inhibitory activity of YS1, YS2, and YS3 against 5-LOX with an IC50 value of 2.7, 4.2, and 5.3 μM, respectively. All three inhibitors significantly decrease LPS-induced TNF-α and IL-6 production, which suggests its potential use an anti-inflammatory agent. In addition, the identified 5-LOX inhibitors contain a novel scaffold. The discovery of these inhibitors presents an opportunity for designing specific anti-inflammatory drugs.

Inhibition of 5-Lipoxygenase-Derived Leukotrienes and Hemiketals as a Novel Anti-Inflammatory Mechanism of Urolithins

SCOPE

Urolithins (Uro), gut microbial metabolites derived from ellagic acid (EA), reach significant concentrations in the human colon. Uro-A exerts anti-inflammatory activity in animal models of inflammatory bowel diseases (IBDs). It is hypothesized that Uro can modulate the biosynthesis of leukocyte-derived inflammatory eicosanoids from the 5-lipoxygenase (5-LOX), cyclooxygenase-2 (COX-2), and 5-LOX/COX-2 pathways, relevant in the onset and progression of IBDs, including 5-hydroxyeicosatetraenoic acids (5-HETEs), leukotriene-B₄ (LTB₄ ), prostaglandin E₂ (PGE₂ ), and hemiketals (HKE₂ and HKD₂ ).

METHODS AND RESULTS

Leukocytes, obtained from six healthy donors, are stimulated with lipopolysaccharide and calcium ionophore A23187. Uro, at concentrations found in the human colon (1-15 µm), decrease eicosanoid biosynthesis and COX-2 levels in the activated leukocytes. In contrast, EA and conjugated Uro (glucuronides and sulfates) are inactive. Uro-A and isourolithin-A reduce the formation of the 5-LOX/COX-2 products HKE₂ and HKD₂ through the COX-2 pathway (down-regulation of COX-2 and PGE2), whereas Uro-C reduces 5-HETE and LTB₄ via inhibition of 5-LOX.

CONCLUSIONS

The results show that physiologically relevant colonic Uro target eicosanoid biosynthetic pathways. The effect on HKs and LTB₄ formation is unprecedented and expands the knowledge on anti-inflammatory mechanisms of Uro against IBDs.

Druggable Sphingolipid Pathways: Experimental Models and Clinical Opportunities

Intensive research in the field of sphingolipids has revealed diverse roles in cell biological responses and human health and disease. This immense molecular family is primarily represented by the bioactive molecules ceramide, sphingosine, and sphingosine 1-phosphate (S1P). The flux of sphingolipid metabolism at both the subcellular and extracellular levels provides multiple opportunities for pharmacological intervention. The caveat is that perturbation of any single node of this highly regulated flux may have effects that propagate throughout the metabolic network in a dramatic and sometimes unexpected manner. Beginning with S1P, the receptors for which have thus far been the most clinically tractable pharmacological targets, this review will describe recent advances in therapeutic modulators targeting sphingolipids, their chaperones, transporters, and metabolic enzymes.

Human cytomegalovirus infection is correlated with enhanced cyclooxygenase-2 and 5-lipoxygenase protein expression in breast cancer

Purpose

While enhanced expression of cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LO) and their derived metabolites is associated with breast cancer (BC) risk, the precise link between BC carcinogenesis and enhanced inflammatory activity remains to be clarified. Human Cytomegalovirus (HCMV) may induce expression of COX-2 and 5-LO and is frequently found in breast cancer biopsies. Thus, we investigated whether there is an association between HCMV proteins and expression of COX-2 and 5-LO in human BC tissue and BC cell lines.

Materials and methods

Paraffin embedded biopsies obtained from 49 patients with breast cancer and 26 tissue samples from adjacent, benign breast tissues were retrospectively examined for HCMV-immediate early (IE), HCMV-Late (LA), COX-2, and 5-LO proteins by immunohistochemistry. In vitro, uninfected and HCMV-infected BC cell lines were examined for COX-2 and 5-LO transcripts and proteins by PCR and flow cytometry.

Results

Extensive expression of COX-2, 5-LO and HCMV-IE proteins were preferentially detected in BC samples. We found a statistically significant concordant correlation between extensive HCMV-IE and COX-2 (P < 0.0001) as well as with HCMV-IE and 5-LO (P = 0.0003) in infiltrating BC. In vitro, HCMV infection induced COX-2 and 5-LO transcripts and COX-2 proteins in MCF-7 cells (P =0.008, P =0.018, respectively). In MDA-MB-231 cells that already had high base line levels of COX-2 expression, HCMV induced both COX-2 and 5-LO proteins but not transcripts.

Conclusion

Our findings demonstrate a significant correlation between extensive HCMV-IE protein expression and overexpression of COX-2 and 5-LO in human breast cancer.

Electronic supplementary material

The online version of this article (10.1007/s00432-019-02946-8) contains supplementary material, which is available to authorized users.

Aspirin alone and combined with a statin suppresses eicosanoid formation in human colon tissue

Eicosanoids, including prostaglandins (PGs) and thromboxanes, are broadly bioactive lipid mediators and increase colon tumorigenesis possibly through chronic inflammatory mechanisms. Epidemiological and experimental data suggest that acetylsalicylic acid (ASA) helps prevent colorectal cancer (CRC), possibly through cyclooxygenase (COX)-mediated suppression of eicosanoid, particularly PGE2, formation. Recent studies suggest that statins prevent CRC and improve survival after diagnosis. We identified patients on ASA and/or statin treatment undergoing routine colonoscopy and measured eicosanoid levels in colonic mucosa with targeted metabolomics technology (LC-MS/MS). ASA-treated individuals (n = 27) had significantly lower tissue eicosanoid levels of most COX-derived metabolites than untreated individuals (n = 31). In contrast, COX-derived lipid metabolites tended to be higher in patients with statin treatment (n = 7) as compared with those not receiving statins (n = 24). This effect was not discernible in subjects treated with ASA and statins (n = 11): Individuals treated with both drugs showed a pronounced suppression of COX-derived eicosanoids in colon tissue, even compared with subjects treated with ASA alone. Our data from a routine clinical setting support the hypothesis that ASA and statins could inhibit CRC development via lipid mediator modification. Further studies should directly investigate the effect of dual ASA and statin treatment on colon tumorigenesis in humans.

Natural Forms of Vitamin E as Effective Agents for Cancer Prevention and Therapy

Initial research on vitamin E and cancer has focused on α-tocopherol (αT), but recent clinical studies on cancer-preventive effects of αT supplementation have shown disappointing results, which has led to doubts about the role of vitamin E, including different vitamin E forms, in cancer prevention. However, accumulating mechanistic and preclinical animal studies show that other forms of vitamin E, such as γ-tocopherol (γT), δ-tocopherol (δT), γ-tocotrienol (γTE), and δ-tocotrienol (δTE), have far superior cancer-preventive activities than does αT. These vitamin E forms are much stronger than αT in inhibiting multiple cancer-promoting pathways, including cyclo-oxygenase (COX)- and 5-lipoxygenase (5-LOX)-catalyzed eicosanoids, and transcription factors such as nuclear transcription factor κB (NF-κB) and signal transducer and activator of transcription factor 3 (STAT3). These vitamin E forms, but not αT, cause pro-death or antiproliferation effects in cancer cells via modulating various signaling pathways, including sphingolipid metabolism. Unlike αT, these vitamin E forms are quickly metabolized to various carboxychromanols including 13'-carboxychromanols, which have even stronger anti-inflammatory and anticancer effects than some vitamin precursors. Consistent with mechanistic findings, γT, δT, γTE, and δTE, but not αT, have been shown to be effective for preventing the progression of various types of cancer in preclinical animal models. This review focuses on cancer-preventive effects and mechanisms of γT, δT, γTE, and δTE in cells and preclinical models and discusses current progress in clinical trials. The existing evidence strongly indicates that these lesser-known vitamin E forms are effective agents for cancer prevention or as adjuvants for improving prevention, therapy, and control of cancer.

Role of the route of leukotrienes in an experimental model of oral mucositis induced by 5-fluorouracil 1

PURPOSE

To investigate the participation of cysteinyl leukotrienes in the pathophysiology of oral mucositis.

METHODS

Oral mucositis was induced in hamsters using 5-fluorouracil (5-FU; 60 and 40 mg/kg; i.p., on days 1 and 2, respectively, and with excoriations in jugal mucosa on day 4). Montelukast (10, 20, or 40 mg/kg/d; gavage), MK886 (3 mg/kg/d, i.p.), or saline or celecoxib (7.5 mg/kg/d; i.p.) was administered 1 h prior to 5-FU and daily, until the fourth (MK886) or tenth day, when the animals were euthanized and their jugal mucosa was collected for macroscopic, histopathological, and immunohistochemical evaluation.

RESULTS

Neither montelukast nor MK-886 prevented the oral mucositis induced by 5-FU, as observed by histopathological evaluation. In addition, we did not find significant differences in the expression of inducible nitric oxide synthase-2, cyclooxygenase-2, or interleukin (IL)-1β between the experimental and control groups. However, we did observe a significant decrease in tumor necrosis factor (TNF)-α expression for all doses of montelukast; we also observed a significant decrease in IL-10 with 40 mg/kg/d and MK 886.

CONCLUSIONS

Cysteinyl leukotrienes do not play an important role in experimental oral mucositis induced by 5-FU. There is a modulating action specifically on TNF-α.

Modulating effect of inositol hexaphosphate on arachidonic acid-dependent pathways in colon cancer cells

Cyclooxygenase (COX) and lipoxygenase (LOX) are key enzymes of arachidonic acid metabolism. Their products, prostaglandins and leukotrienes, are involved in the pathogenesis of inflammatory bowel diseases and colorectal cancer. The aim of the study was to examine the influence of inositol hexaphosphate (IP6), a naturally occurring phytochemical, on the expression of genes encoding COX and LOX isoforms and synthesis of their products (PGE₂ and LTB₄) in colon cancer cell line Caco-2 stimulated with pro-inflammatory agents (IL-1β/TNFα). Real-time RT-qPCR was used to validate mRNAs level of examined genes. The concentrations of COX-2 and 5-LOX proteins as well as PGE2 and LTB4 were determined by the ELISA method. Based on these studies it may be concluded that IP6 may limit inflammatory events in the colonic epithelium and prevent colon carcinomas by modulating the expression of genes encoding COX and LOX isoforms at both mRNA and protein levels as well as by affecting the synthesis and secretion of prostaglandins and leukotrienes.

The anti-inflammatory effects of Yunnan Baiyao are involved in regulation of the phospholipase A2/arachidonic acid metabolites pathways in acute inflammation rat model

The traditional Chinese medicine Yunnan Baiyao (YNB) has been reported to possess anti-inflammatory properties, however its mechanism of action remains unclear. It was previously reported that YNB ameliorated depression of arachidonic acid (AA) levels in a rat model of collagen-induced arthritis. In the current study, the capacity of YNB to ameliorate inflammation was compared in carrageenan-induced and AA-induced acute inflammation of the rat paw with celecoxib and mizolastine, respectively (n=24 per group). The capacity of YNB to affect the phospholipase A2 (PLA2)/AA pathway (using reverse transcription-quantitative polymerase chain reaction) and release of inflammatory lipid mediators (by ELISA) were investigated. Celecoxib ameliorated carrageenan-induced paw edema, and mizolastine ameliorated AA-induced rat paw edema. YNB alleviated paw edema and inhibited inflammatory cell infiltration in the two models. YNB inhibited production of 5-LOX AA metabolite leukotriene B4 (LTB4), and suppressed expression of 5-LOX, cytosolic PLA2 (cPLA2), 5-LOX-activating protein, and LTB4 receptor mRNA in the AA-induced inflammation model (P<0.05). YNB Inhibited the production of the COX-2 AA metabolite prostaglandin E2 (PGE2) and suppressed expression of COX-2, cPLA2, PGE2 mRNA in the carrageenan-induced inflammation mode (P<0.05). Taken together, the data suggest that modulation of COX and LOX pathways in AA metabolism represent a novel anti-inflammatory mechanism of YNB.

Synthesis of N-alkyl-3-sulfonylindoles and N-alkyl-3-sulfanylindoles by cascade annulation of 2-alkynyl-N,N-dialkylanilines

Divergent synthesis of N-alkyl-3-sulfonylindoles and N-alkyl-3-sulfanylindoles from 2-alkynyl-N,N-dialkylanilines and sulfonyl hydrazides has been described.

Evaluation of Cysteinyl Leukotriene Signaling as a Therapeutic Target for Colorectal Cancer

Colorectal cancer is the third most common cancer worldwide and is associated with significant morbidity and mortality. Current pharmacotherapy options include cytotoxic chemotherapy, anti-VEGF, and anti-EGFR targeting drugs, but these are limited by toxic side effects, limited responses and ultimately resistance. Cysteinyl leukotriene (CysLT) signaling regulates intestinal homeostasis with mounting evidence suggesting that CysLT signaling also plays a role in the pathogenesis of colorectal cancer. Therefore, CysLT signaling represents a novel target for this malignancy. This review evaluates reported links between CysLT signaling and established hallmarks of cancer in addition to its pharmacological potential as a new therapeutic target.

Synthesis, in vitro anticancer and antibacterial activities and in silico studies of new 4-substituted 1,2,3-triazole-coumarin hybrids

The 4-substituted 1,2,3-triazole core in designed coumarin hybrids (4-35) with diverse physicochemical properties was introduced by eco-friendly copper(I)-catalyzed Huisgen 1,3-dipolar cycloaddition under microwave irradiation. Coumarin-1,2,3-triazole-benzofused heterocycle hybrids emerged as the class of compounds exhibiting the highest antiproliferative activity. The strong relationship between lipophilicity and antiproliferative activities was observed indicating that lipophilic 1,2,3-triazole-coumarin hybrids containing phenylethyl (13), 3,5-difluorophenyl (14), 5-iodoindole (30) and benzimidazole (33 and 35) subunits showed the most potent cytostatic effects. The 7-methylcoumarin-1,2,3-triazole-2-methylbenzimidazole hybrid 33 can be highlighted as a lead that exerted the highest cytotoxicity against hepatocellular carcinoma HepG2 cells with IC₅₀ value of 0.9 μM and high selectivity (SI = 50). This compound induced cell death, mainly due to early apoptosis. Strong antiproliferative effect of 33 could be associated with its inhibition of 5-lipoxygenase (5-LO) activity and perturbation of sphingolipid signaling by interfering with intracellular acid ceramidase (ASAH) activity. Outlined considerable effect of lipophilicity on antiproliferative activity was not observed for antibacterial activity. The compounds with p-pentylphenyl (17), 2-chloro-4-fluorobenzenesulfonamide (23) and dithiocarbamate (27) moiety were endowed with high selectivity against Enterococcus species. Moreover, these compounds were found to be superior in inhibiting the growth of clinically isolated vancomycin-resistant Enterococcus faecium, while the reference antibiotics exhibited the lack of activity. Our findings indicate that coumarin-1,2,3-triazole could be used as the scaffold for structural optimization to develop more potent and selective anticancer agents and encourage further development of novel structurally related analogs of 33 as more effective 5-LO inhibitors.

Role of histamine H4 receptor ligands in bleomycin-induced pulmonary fibrosis

Fibrosis of lung tissue is a disease where a chronic inflammatory process determines a pathological remodelling of lung parenchyma. The animal model obtained by intra-tracheal administration of bleomycin in C57BL/6 mice is one of the most validated murine model. Bleomycin stimulates oxidative stress and the production of pro-inflammatory mediators. Histamine H4R have recently been implicated in inflammation and immune diseases. This study was focused to investigate the effects of H4R ligands in the modulation of inflammation and in the reduction of lung fibrosis in C57BL/6 mice treated with bleomycin. C57BL/6 mice were treated with vehicle, JNJ7777120 (JNJ, selective H4R antagonist) or ST-1006 (partial H4R agonist), ST-994 (H4R neutral antagonist) and ST-1012 (inverse H4R agonist) at equimolar doses, released by micro-osmotic pumps for 21days. Airway resistance to inflation was assayed and lung samples were processed to measure malondialdehyde (TBARS); 8-hydroxy-2'-deoxyguanosine (8OHdG); myeloperoxidase (MPO); COX-2 expression and activity as markers of oxidative stress and inflammation. Fibrosis and airway remodelling were evaluated throughout transforming growth factor-β (TGF-β), percentage of positive Goblet cells, smooth muscle layer thickness determination. Our results indicated that JNJ, ST-994 and ST-1012 decreased inflammation and oxidative stress markers, i.e. the number of infiltrating leukocytes evaluated as lung tissue MPO, COX-2 expression and activity, TBARS and 8OHdG production. They also reduced the level of TGF-β, a pro-fibrotic cytokine, collagen deposition, thickness of smooth muscle layer, Goblet cells hyperplasia; resulting in a decrease of airway functional impairment. The results here reported clearly demonstrated that H4R ligands have a beneficial effect in a model of lung fibrosis in the mouse, thus indicating that H4R antagonists or inverse agonists could be a novel therapeutic strategy for lung inflammatory diseases.

Catalytic Synthesis of 3-Thioindoles Using Bunte Salts as Sulfur Sources under Metal-Free Conditions

An efficient catalytic method for the synthesis of 3-thioindoles has been successfully developed, which uses odorless, stable, readily available crystalline Bunte salts as the sulfenylating agents, iodine as nonmetallic catalyst, and DMSO as both the oxidant and solvent. This method is practical and environmentally benign in terms of sulfur sources, catalyst, and solvent. The catalytic reaction is selective at the C3 position of indoles and compatible with a wide range of substrates, giving the desired products in good to excellent yields.

Eicosanoid pathway in colorectal cancer: Recent updates

Enzymatic metabolism of the 20C polyunsaturated fatty acid (PUFA) arachidonic acid (AA) occurs via the cyclooxygenase (COX) and lipoxygenase (LOX) pathways, and leads to the production of various bioactive lipids termed eicosanoids. These eicosanoids have a variety of functions, including stimulation of homeostatic responses in the cardiovascular system, induction and resolution of inflammation, and modulation of immune responses against diseases associated with chronic inflammation, such as cancer. Because chronic inflammation is essential for the development of colorectal cancer (CRC), it is not surprising that many eicosanoids are implicated in CRC. Oftentimes, these autacoids work in an antagonistic and highly temporal manner in inflammation; therefore, inhibition of the pro-inflammatory COX-2 or 5-LOX enzymes may subsequently inhibit the formation of their essential products, or shunt substrates from one pathway to another, leading to undesirable side-effects. A better understanding of these different enzymes and their products is essential not only for understanding the importance of eicosanoids, but also for designing more effective drugs that solely target the inflammatory molecules found in both chronic inflammation and cancer. In this review, we have evaluated the cancer promoting and anti-cancer roles of different eicosanoids in CRC, and highlighted the most recent literature which describes how those molecules affect not only tumor tissue, but also the tumor microenvironment. Additionally, we have attempted to delineate the roles that eicosanoids with opposing functions play in neoplastic transformation in CRC through their effects on proliferation, apoptosis, motility, metastasis, and angiogenesis.

Co-expression of COX-2 and 5-LO in primary glioblastoma is associated with poor prognosis

Cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LO) are important factors in tumorigenesis and malignant progression; however, studies of their roles in glioblastoma have produced conflicting results. To define the frequencies of COX-2 and 5-LO expression and their correlation with clinicopathological features and prognosis, tumor tissues from 76 cases of newly diagnosed primary ordinary glioblastoma were examined for COX-2 and 5-LO expression by immunohistochemistry. The expression levels of COX-2 and 5-LO and the relationships between the co-expression of COX-2/5-LO and patient age and gender, edema index (EI), Karnofsky Performance Scale and overall survival (OS) were analyzed. COX-2 and 5-LO were expressed in 73.7 % (56/76) and 92.1 % (70/76) of the samples, respectively. Among the clinicopathological characteristics, only age (>60 years) exhibited a significant association with the high expression of COX-2. No statistically significant correlations were found in the 5-LO cohort. A significant positive correlation was revealed between the COX-2 and 5-LO scores (r = 0.374; p = 0.001). The elevated co-expression of COX-2 and 5-LO was observed primarily in the patients over the age of 60 years. Patients with a high expression of COX-2 had a significantly shorter OS (p < 0.01), whereas the immunoexpression of 5-LO was not associated with the OS of patients with glioblastoma. Survival analysis indicated that simultaneous high levels of COX-2 and 5-LO expression were significantly correlated with poor OS and, conversely, that a low/low expression pattern of these two proteins was significantly associated with better OS (p < 0.05). Moreover, the Cox multivariable proportional hazard model showed that a high expression of COX-2, high co-expression of COX-2 and 5-LO, and a high Ki-67 index were significant predictors of shorter OS in primary glioblastoma, independent of age, gender, EI, 5-LO expression and p53 status. The hazard ratios for OS were 2.347 (95 % CI 1.30-4.25, p = 0.005), 1.900 (95 % CI 1.30-2.78, p = 0.001), and 2.210 (95 % CI 1.19-4.09, p = 0.011), respectively. These results suggest that COX-2 and 5-LO play roles in tumorigenesis and the progression of primary glioblastoma and that the co-expression pattern of COX-2/5-LO may be used as an independent prognostic factor in this disease.

Leukotriene D4-induced Caco-2 cell proliferation is mediated by prostaglandin E2 synthesis

Leukotriene D₄ (LTD₄) is a pro-inflammatory mediator formed from arachidonic acid through the action of 5-lipoxygenase (5-LOX). Its biological effects are mediated by at least two G-coupled plasmatic cysteinyl LT receptors (CysLT_1-2R). It has been reported an upregulation of the 5-LOX pathway in tumor tissue unlike in normal colon mucosa. Colon tumors generally have an increased expression of CysLT₁R and colon cancer patients with high expression levels of CysLT₁R have poor prognosis. We previously observed that the cyclooxygenase pathway is involved in the control of intestinal epithelial cancer cell growth through PGE₂ production. The aim of this study was therefore to assess the effect of LTD₄ binding with CysLT₁R on Caco-2 cell growth. We note a number of key findings from this research. We observed that at a concentration similar to that found under inflammatory conditions, LTD₄ was able to induce Caco-2 cell proliferation and DNA synthesis. Moreover, with the use of a specific receptor antagonist this study has demonstrated that the effect of LTD₄ is a result of its interaction with CystLT₁R. We also note the possible participation of the PLC-IP₃-Ca²⁺/DAG-PKC signaling pathways in cytosolic PLA₂ and [³H]AA release induced by LTD₄-CystLT₁R interaction. Finally, we found that the resulting activation of the AA cascade and the production of PGE₂ eicosanoid could be related to the activation of cell signaling pathways such as ERK and CREB. These findings will help facilitate our understanding of how inflammatory mediators can affect the survival and dissemination of intestinal carcinoma cells.

Anti-proliferative and pro-apoptotic effects of lichen-derived compound protolichesterinic acid are not mediated by its lipoxygenase-inhibitory activity

Lipoxygenases (LOXs) and their products are involved in several biological functions and have been associated with carcinogenesis. Protolichesterinic acid (PA), a lichen metabolite, inhibits 5- and 12-LOX and has anti-proliferative effects on various cancer cell lines. Here, PA was shown to inhibit proliferation of multiple myeloma cells, RPMI 8226 and U266, and pancreatic cancer cells AsPC-1. Apoptosis was induced only in multiple myeloma cells. Cell-cycle associated changes in expression and sub-cellular localization of 5- and 12-LOX were not affected by PA but increased cytoplasmic localisation was found to accompany morphological changes at later stages. Assessment by mass spectrometry showed that PA entered the pancreatic cancer cells. However, effects on LOX metabolites were only evident after treatment with concentrations exceeding those having anti-proliferative effects and no effects were measurable in the myeloma cells. We conclude that the anti-proliferative and pro-apoptotic effects of PA are not mediated directly through inhibition of LOX activity.

A phase 2 randomized, double-blind, placebo-controlled study of the effect of VIA-2291, a 5-lipoxygenase inhibitor, on vascular inflammation in patients after an acute coronary syndrome

OBJECTIVE

Arachidonate 5-lipoxygenase (5-LO) is a key enzyme in the synthesis of leukotrienes. VIA-2291 is a potent 5-LO inhibitor, which has been shown to reduce hsCRP and noncalcified coronary plaque volume following an acute coronary syndrome (ACS). We aim to evaluate the effect of VIA-2291 on vascular inflammation compared to placebo using FDG-PET.

METHODS

A Phase II, randomized, double-blind, parallel-group study was conducted in 52 patients with recent ACS assigned 1:1 to either 100 mg VIA-2291 or placebo for 24 weeks. The primary outcome was the effect of VIA-2291 relative to placebo on arterial inflammation detected by (18)fluorodeoxyglucose positron emission tomography (FDG-PET) within the index vessel after 24 weeks of daily treatment, compared to baseline.

RESULTS

VIA-2291 was relatively well tolerated and was associated with a significant inhibition of the potent chemo-attractant LTB4, with a mean inhibition of activity of 92.8% (p<0.0001) at 6 weeks in the VIA-2291 group, without further significant change in inhibition at 24 weeks. However, for VIA-2291 was not associated with significant difference in inflammation (target-to-background ratio) compared to placebo at 24 weeks or 6 weeks of treatment. Further, VIA-2291 was not associated with a significant reduction in hsCRP from baseline after either 6 or 24 weeks of treatment.

CONCLUSIONS

VIA-2291 is well-tolerated and effectively reduces leukotriene production. However, inhibition of 5-LO with VIA-2291 is not associated with significant reductions in vascular inflammation (by FDG-PET) or in blood inflammatory markers. Accordingly, this study does not provide evidence to support a significant anti-inflammatory effect of VIA-2291 in patients with recent ACS.

Potency of non-steroidal anti-inflammatory drugs in chemotherapy

Cancer cell resistance, particularly multidrug resistance (MDR), is the leading cause of chemotherapy failure. A number of mechanisms involved in the development of MDR have been described, including the overexpression of ATP-dependent membrane-bound transport proteins. The enhanced expression of these proteins, referred to as ATP-binding cassette (ABC) transporters, results in an increased cellular efflux of the cytotoxic drug, thereby reducing its intracellular concentration to an ineffective level. Non-steroidal anti-inflammatory drugs (NSAIDs) are the most frequently consumed drugs worldwide. NSAIDs are mainly used to treat pain, fever and inflammation. Numerous studies suggest that NSAIDs also show promise as anticancer drugs. NSAIDs have been shown to reduce cancer cell proliferation, motility, angiogenesis and invasiveness. In addition to these effects, NSAIDs have been shown to induce apoptosis in a wide variety of cancer types. Moreover, several studies have indicated that NSAIDs may sensitise cancer cells to the antiproliferative effects of cytotoxic drugs by modulating ABC transporter activity. Therefore, combining specific NSAIDs with chemotherapeutic drugs may have clinical applications. Such treatments may allow for the use of a lower dose of cytotoxic drugs and may also enhance the effectiveness of therapy. The objective of this review was to discuss the possible role of NSAIDs in the modulation of antitumour drug cytotoxicity. We particularly emphasised on the use of COX-2 inhibitors in combination with chemotherapy and the molecular and cellular mechanisms underlying the alterations in outcome that occur in response to this combination therapy.

Somatic mutations in arachidonic acid metabolism pathway genes enhance oral cancer post-treatment disease-free survival

The arachidonic acid metabolism (AAM) pathway promotes tumour progression. Chemical inhibitors of AAM pathway prolong post-treatment survival of cancer patients. Here we test whether non-synonymous somatic mutations in genes of this pathway, acting as natural inhibitors, increase post-treatment survival. We identify loss-of-function somatic mutations in 15 (18%) of 84 treatment-naïve oral cancer patients by whole-exome sequencing, which we map to genes of AAM pathway. Patients (n = 53) who survived ≥ 12 months after surgery without recurrence have significantly (P = 0.007) higher proportion (26% versus 3%) of mutations than those who did not (n = 31). Patients with mutations have a significantly (P = 0.003) longer median disease-free survival (24 months) than those without (13 months). Compared with the presence of a mutation, absence of any mutation increases the hazard ratio for death (11.3) significantly (P = 0.018). The inferences are strengthened when we pool our data with The Cancer Genome Atlas (TCGA) data. In patients with AAM pathway mutations, some downstream pathways, such as the PI3K-Akt pathway, are downregulated.

A selective antagonist of histamine H₄ receptors prevents antigen-induced airway inflammation and bronchoconstriction in guinea pigs: involvement of lipocortin-1

BACKGROUND AND PURPOSE

Among the pathogenic mechanisms of asthma, a role for oxidative/nitrosative stress has been well documented. Recent evidence suggests that histamine H₄ receptors play a modulatory role in allergic inflammation. Here we report the effects of compound JNJ 7777120 (JNJ), a selective H4 receptor antagonist, on antigen-induced airway inflammation, paying special attention to its effects on lipocortin-1 (LC-1/annexin-A1), a 37 kDA anti-inflammatory protein that plays a key role in the production of inflammatory mediators.

EXPERIMENTAL APPROACH

Ovalbumin (OA)-sensitized guinea pigs placed in a respiratory chamber were challenged with antigen. JNJ (5, 7.5 and 10 mg.kg⁻¹) was given i.p. for 4 days before antigen challenge. Respiratory parameters were recorded. Bronchoalveolar lavage (BAL) fluid was collected and lung specimens taken for further analyses 1 h after antigen challenge. In BAL fluid, levels of LC-1, PGD2 , LTB4 and TNF-α were measured. In lung tissue samples, myeloperoxidase, caspase-3 and Mn-superoxide dismutase activities and 8-hydroxy-2-deoxyguanosine levels were measured.

KEY RESULTS

OA challenge decreased LC-1 levels in BAL fluid, induced cough, dyspnoea and bronchoconstriction and increased PGD2 , LTB4 and TNF-α levels in lung tissue. Treatment with JNJ dose-dependently increased levels of LC-1, reduced respiratory abnormalities and lowered levels of PGD2 , LTB4 and TNF-α in BAL fluid.

CONCLUSIONS AND IMPLICATIONS

Antigen-induced asthma-like reactions in guinea pigs decreased levels of LC-1 and increased TNF-α and eicosanoid production. JNJ pretreatment reduced allergic asthmatic responses and airway inflammation, an effect associated with LC-1 up-regulation.

ω-3 polyunsaturated fatty acids-derived lipid metabolites on angiogenesis, inflammation and cancer

Epidemiological and pre-clinical studies support the anti-tumor effects of ω-3 PUFAs; however, the results from human trials are mixed, making it difficult to provide dietary guidelines or recommendations of ω-3 PUFAs for disease prevention or treatment. Understanding the molecular mechanisms by which ω-3 PUFAs inhibit cancer could lead to better nutritional paradigms and human trials to clarify their health effects. The ω-3 PUFAs exert their biological activities mainly through the formation of bioactive lipid metabolites. Here we discuss the biology of cyclooxygenase, lipoxygenase and cytochrome P450 enzymes-derived ω-3-series lipid metabolites on angiogenesis, inflammation and cancer.

A solvent- and metal-free synthesis of 3-chacogenyl-indoles employing DMSO/I2 as an eco-friendly catalytic oxidation system

Herein, we describe a solvent- and metal-free method for the synthesis of 3-chalcogenyl-indoles from indoles and diorganyl dichalcogenides using an equivalent amount of DMSO as an oxidant, under catalysis by molecular iodine. This mild and eco-friendly approach allowed the preparation of a wide range of 3-selenyl- and 3-sulfenyl-indoles in good to excellent yields.

Cysteinyl leukotrienes and their receptors: Bridging inflammation and colorectal cancer

Long-standing inflammation has emerged as a hallmark of neoplastic transformation of epithelial cells and may be a limiting factor of successful conventional tumor therapies. A complex milieu composed of distinct stromal and immune cells, soluble factors and inflammatory mediators plays a crucial role in supporting and promoting various types of cancers. An augmented inflammatory response can predispose a patient to colorectal cancer (CRC). Common risk factors associated with CRC development include diet and lifestyle, altered intestinal microbiota and commensals, and chronic inflammatory bowel diseases. Cysteinyl leukotrienes are potent inflammatory metabolites synthesized from arachidonic acid and have a broad range of functions involved in the etiology of various pathologies. This review discusses the important role of cysteinyl leukotriene signaling in linking inflammation and CRC.