The BCL-2 inhibitor APG-2575 resets tumor-associated macrophages toward the M1 phenotype, promoting a favorable response to anti-PD-1 therapy via NLRP3 activation.

The main challenges in the use of immune checkpoint inhibitors (ICIs) are ascribed to the immunosuppressive tumor microenvironment and the lack of sufficient infiltration of activated CD8+ T cells. Transforming the tumor microenvironment (TME) from "cold" to "hot" and thus more likely to potentiate the effects of ICIs is a promising strategy for cancer treatment. We found that the selective BCL-2 inhibitor APG-2575 can enhance the antitumor efficacy of anti-PD-1 therapy in syngeneic and humanized CD34+ mouse models. Using single-cell RNA sequencing, we found that APG-2575 polarized M2-like immunosuppressive macrophages toward the M1-like immunostimulatory phenotype with increased CCL5 and CXCL10 secretion, restoring T-cell function and promoting a favorable immunotherapy response. Mechanistically, we demonstrated that APG-2575 directly binds to NF-κB p65 to activate NLRP3 signaling, thereby mediating macrophage repolarization and the activation of proinflammatory caspases and subsequently increasing CCL5 and CXCL10 chemokine production. As a result, APG-2575-induced macrophage repolarization could remodel the tumor immune microenvironment, thus improving tumor immunosuppression and further enhancing antitumor T-cell immunity. Multiplex immunohistochemistry confirmed that patients with better immunotherapeutic efficacy had higher CD86, p-NF-κB p65 and NLRP3 levels, accompanied by lower CD206 expression on macrophages. Collectively, these data provide evidence that further study on APG-2575 in combination with immunotherapy for tumor treatment is required.

Blockade of Cycloxygenase-2 ameliorates sepsis induced immune-suppression by regulating myeloid-derived suppressor cells.

BACKGROUND: Myeloid-derived suppressor cells (MDSCs) and cyclooxy-genase-2 (COX-2)/Prostaglandin E2 (PGE2) axis are important contributors to sepsis-induced immune-suppression. The purpose of present study is to explore whether COX-2 inhibitor can improve immunological disorder after sepsis via regulating MDSCs. METHODS: A ''two-hit'' model reflecting clinical sepsis development was performed. Cecal ligation and puncture (CLP) and Legionella pneumophila infection were used as the first and the second hit, respectively. NS398, a selective COX-2 inhibitor, was utilized to treat septic mice. The motality, bacterial counts in the lung, systematic inflammatory reaction and CD4 + T cells response after sepsis were assessed, so as the frequency and function of MDSCs. In some experiments, the number of MDSCs was manipulated by adoptive transfer or neutralizing antibody before induction of secondary infection. RESULTS: Mice surviving CLP showed a marked expansion and activation of MDSCs in spleen, accompanied by suppressed proliferating capability, impaired secreting functionand increased apoptosis of CD4 + T cells. Majority of CLP survivors became succumbed to L. pneumophila invasion, associated with defective bacteria elimination ability. NS398 treatment was found to ameliorate these adverse outcomes significantly. CONCLUSION: MDSCs contribute greatly to the sepsis-induced immune dysfunction. Inhibiting COX-2 may become a promising therapy that targets MDSCs-induced immunosuppression.

NS398 as a potential drug for autosomal-dominant polycystic kidney disease: Analysis using bioinformatics, and zebrafish and mouse models.

Autosomal-dominant polycystic kidney disease (ADPKD) is characterized by uncontrolled renal cyst formation, and few treatment options are available. There are many parallels between ADPKD and clear-cell renal cell carcinoma (ccRCC); however, few studies have addressed the mechanisms linking them. In this study, we aimed to investigate their convergences and divergences based on bioinformatics and explore the potential of compounds commonly used in cancer research to be repurposed for ADPKD. We analysed gene expression datasets of ADPKD and ccRCC to identify the common and disease-specific differentially expressed genes (DEGs). We then mapped them to the Connectivity Map database to identify small molecular compounds with therapeutic potential. A total of 117 significant DEGs were identified, and enrichment analyses results revealed that they are mainly enriched in arachidonic acid metabolism, p53 signalling pathway and metabolic pathways. In addition, 127 ccRCC-specific up-regulated genes were identified as related to the survival of patients with cancer. We focused on the compound NS398 as it targeted DEGs and found that it inhibited the proliferation of Pkd1-/- and 786-0 cells. Furthermore, its administration curbed cystogenesis in Pkd2 zebrafish and early-onset Pkd1-deficient mouse models. In conclusion, NS398 is a potential therapeutic agent for ADPKD.

Simultaneous CK2/TNIK/DYRK1 inhibition by 108600 suppresses triple negative breast cancer stem cells and chemotherapy-resistant disease.

Triple negative breast cancer (TNBC) remains challenging because of heterogeneous responses to chemotherapy. Incomplete response is associated with a greater risk of metastatic progression. Therefore, treatments that target chemotherapy-resistant TNBC and enhance chemosensitivity would improve outcomes for these high-risk patients. Breast cancer stem cell-like cells (BCSCs) have been proposed to represent a chemotherapy-resistant subpopulation responsible for tumor initiation, progression and metastases. Targeting this population could lead to improved TNBC disease control. Here, we describe a novel multi-kinase inhibitor, 108600, that targets the TNBC BCSC population. 108600 treatment suppresses growth, colony and mammosphere forming capacity of BCSCs and induces G2M arrest and apoptosis of TNBC cells. In vivo, 108600 treatment of mice bearing triple negative tumors results in the induction of apoptosis and overcomes chemotherapy resistance. Finally, treatment with 108600 and chemotherapy suppresses growth of pre-established TNBC metastases, providing additional support for the clinical translation of this agent to clinical trials.

Design, Synthesis, and Evaluation of o-(Biphenyl-3-ylmethoxy)nitrophenyl Derivatives as PD-1/PD-L1 Inhibitors with Potent Anticancer Efficacy In Vivo.

Two series of novel o-(biphenyl-3-ylmethoxy)nitrophenyl compounds (A1-31 and B1-17) were designed as programmed cell death protein 1 (PD-1)/PD-ligand 1 (PD-L1) inhibitors. All compounds showed significant inhibitory activity with IC50 values ranging from 2.7 to 87.4 nM except compound A17, and compound B2 displayed the best activity. Further experiments showed that B2 bound to the PD-L1 protein without obvious toxicity in Lewis lung carcinoma (LLC) cells. Furthermore, B2 significantly promoted interferon-gamma secretion in a dose-dependent manner in vitro and in vivo. Especially, B2 exhibited potent in vivo anticancer efficacy in an LLC-bearing allograft mouse model at a low dose of 5 mg/kg, which was more active than BMS-1018 (tumor growth inhibition rate: 48.5% vs 17.8%). A panel of immunohistochemistry and flow cytometry assays demonstrated that B2 effectively counteracted PD-1-induced immunosuppression in the tumor microenvironment, thereby triggering antitumor immunity. These results indicate that B2 is a promising PD-1/PD-L1 inhibitor worthy of further development.

Activation of alpha7 nicotinic acetylcholine receptor protects bovine endometrial tissue against LPS-induced inflammatory injury via JAK2/STAT3 pathway and COX-2 derived prostaglandin E2.

Bovine endometritis is one of the major postpartum diseases associated with infertility and subfertility, decreasing the benefit of dairy industry. It is important to develop alternate therapies for endometritis in the context of drug residues in the milk and hormone disorder in the estrous cycle. α7 nicotine acetylcholine receptor has been identified as the core of 'cholinergic anti-inflammatory pathway (CAP)', which is a potential drug target to inflammatory diseases. However, there has been still no study on its anti-inflammatory effects and mechanism on lipopolysaccharide (LPS)-induced bovine endometritis. This study aimed to demonstrate the underlying anti-inflammatory effects and mechanism of α7-nACh receptor on LPS-induced inflammation in bovine endometrial tissues cultured in vitro. The results suggested that activation of α7-nACh receptor significantly suppressed the mRNA expression levels of interleukin 1ß (IL-1ß), IL-6, IL-8, and tumor necrosis factor alpha (TNF-α) in bovine endometrial tissues. Western blot and enzyme-linked immunosorbent assay (ELISA) detection results showed that activation of α7-nACh receptor inhibited LPS-induced phosphorylation of Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3). Moreover, α7-nACh receptor agonist decreased the expression of cyclooxygenase 2 (COX-2) and microsomal prostaglandin E synthase-1(mPGES-1), as well as prostaglandin E2 (PGE2) secretion. Interestingly, in COX-2 inhibition experiment, activation of α7-nACh receptor increased COX-2 expression and PGE2 production, compared with COX-2 inhibitor treatment. In conclusion, activation of the cholinergic system through α7-nACh receptor agonist has suppressed inflammation of bovine endometrial tissues via JAK2/STAT3 pathway and potential COX-2-derived PGE2.

Naoxintong restores ischemia injury and inhibits thrombosis via COX2-VEGF/ NFκB signaling.

ETHNOPHARMACOLOGICAL RELEVANCE: Naoxintong (NXT) is a traditional Chinese medicine preparation that is often used in combination with aspirin in the treatment of cardiovascular diseases (CVD). One of the main symptoms of CVD is hypoxic-ischemia (HI). The purpose of this study is to find out the molecular nodes targeted by NXT and its related molecular pathways in vascular repair. MATERIALS AND METHODS: First, human vein umbilical endothelial cells (EA.hy926) were utilized to set up the Oxygen-Glucose Deprivation-Reoxygenation (OGD/R) model and treated with NXT. Cell proliferation, damage and apoptosis were detected by MTT, LDH, and flow cytometry assays. Second, transcriptional responses of OGD/R cells to NXT treatment were investigated. qRT-PCR, western blotting and inhibitor assays were performed. Third, the anti-thrombotic effect of NXT was evaluated by the zebrafish thrombosis model. Morphological observation, histological staining and qRT-PCR assays were implemented on zebrafish model to further observe in vivo the therapeutic effects of NXT on ischemia and thrombosis. RESULTS: In OGD/R EA.hy926 cells, NXT treatment could reduce ischemic vascular injury, increase cell viability and decrease the proportion of apoptosis. Through RNA-seq analysis, 183 differentially expressed genes (DEGs) were screened with 110 up-regulated genes and 73 down-regulated genes between OGD/R and OGD/R + NXT treated EA.hy926 cells. VEGF and NFκB pathways were enriched. Among these genes, COX2 was identified as one of important targets via which NXT could restore vascular injury. COX2 inhibitor (NS-398), and aspirin, a drug that prevents the development of CVD by targeting COX2, exhibited similar effects to NXT in the treatment of OGD/R EA.hy926 cells. In zebrafish thrombosis model, NXT could attenuate tail venous thrombus and recover the quantity of heart red blood cells. Furthermore, NXT could prevent the formulation of thrombosis and eliminate inflammation in zebrafish by COX2-VEGF/NFκB signaling. CONCLUSION: Our studies implicated that NXT could restore HI injury and inhibit thrombosis through COX2-VEGF/NFκB signaling, which is consistent with the molecular target of aspirin. This finding might explain the principle of NXT combined with aspirin in the treatment of cardiovascular diseases.

Combined Poziotinib with Manidipine Treatment Suppresses Ovarian Cancer Stem-Cell Proliferation and Stemness.

Epithelial ovarian cancer (EOC) is the most lethal gynecological malignancy in women worldwide, with an overall 5 year survival rate below 30%. The low survival rate is associated with the persistence of cancer stem cells (CSCs) after chemotherapy. Therefore, CSC-targeting strategies are required for successful EOC treatment. Pan-human epidermal growth factor receptor 4 (HER4) and L-type calcium channels are highly expressed in ovarian CSCs, and treatment with the pan-HER inhibitor poziotinib or calcium channel blockers (CCBs) selectively inhibits the growth of ovarian CSCs via distinct molecular mechanisms. In this study, we tested the hypothesis that combination treatment with poziotinib and CCBs can synergistically inhibit the growth of ovarian CSCs. Combined treatment with poziotinib and manidipine (an L-type CCB) synergistically suppressed ovarian CSC sphere formation and viability compared with either drug alone. Moreover, combination treatment synergistically reduced the expression of stemness markers, including CD133, KLF4, and NANOG, and stemness-related signaling molecules, such as phospho-STAT5, phospho-AKT, phospho-ERK, and Wnt/ß-catenin. Moreover, poziotinib with manidipine dramatically induced apoptosis in ovarian CSCs. Our results suggest that the combinatorial use of poziotinib with a CCB can effectively inhibit ovarian CSC survival and function.

NS398, a cyclooxygenase-2 inhibitor, reverses memory performance disrupted by imipramine in C57Bl/6J mice.

Imipramine has been widely used as an antidepressant in the clinic over the years. Unfortunately, it produces a detrimental effect on memory. At the same time, COX-2 inhibitors engagement in the mechanisms of memory formation, and synapse plastic changes has been well documented. Our previous studies have demonstrated the contribution of cyclooxygenase-2 (COX-2) inhibition to the parameters of the mGluR5 pathway in memory formation. Because chronic administration of imipramine has been shown to affect mGluR5, the purpose of this study was to verify the hypothesis of COX-2 pathway engagement in disrupting effects of imipramine. Imipramine is currently used as a reference compound, and therefore it seems important to decipher and understand mood-related pathways, as well as cognitive changes activated during its use. This study covers the examination of spatial, and motor parameters. To this end, C57Bl/6J mice received imipramine, and NS398 (a COX-2 inhibitor) alone, or in combination for 7 or 14 days. We performed the modified Barnes maze (MBM), modified rotarod (MR) tests, and electrophysiological studies. The harmful effect of imipramine on MBM learning was improved by NS398 use. The same modulatory role of the COX-2 inhibitor in procedural learning in the MR test was found. In conclusion, our data show the involvement of the COX-2 pathway in changes in the long-term memory, and procedural memory of C57Bl/6J mice after chronic imipramine treatment.

OSU-A9 induced-reactive oxygen species cause cytotoxicity in duodenal and gastric cancer cells by decreasing phosphorylated nuclear pyruvate kinase M2 protein levels.

Pyruvate kinase M2 (PKM2) is a key enzyme responsible for the final step of glycolysis. It is still unclear whether PKM2 is involved in reactive oxygen species (ROS)-mediated cytotoxicity in gastrointestinal cancer, and what mechanisms are involved. One duodenal (AZ521) and two gastric (NUGC and SCM-1) cancer cell lines were treated with an indole-3-carbinol derivative OSU-A9, which caused cytotoxicity in acute myeloid leukemia through ROS generation. OSU-A9 caused a dose- and time-dependent cytotoxicity and induced apoptosis in duodenal and gastric cancer cells through ROS generation. Pretreatment with ROS scavengers rescued cancer cells from apoptosis and concomitant poly (ADP-ribose) polymerase cleavage, implying a key role of ROS in OSU-A9-induced cell death. Moreover, OSU-A9-induced ROS generation decreased protein levels of pTyr105-PKM2, and this effect was rescued by pretreatment with ROS scavengers. Interestingly, pTyr105-PKM2 protein levels decreased in the cell nucleus rather than in the cytoplasm. PKM2 overexpression partially rescued the survival of duodenal and gastric cancer cells treated with OSU-A9. Furthermore, the anticancer activity of OSU-A9 extended in vivo, as OSU-A9 administered by oral gavage suppressed the growth of AZ521 xenograft tumors in nude mice without obvious toxicity. In conclusion, OSU-A9 inhibited duodenal and gastric cancer cell proliferation through ROS generation and caused a subsequent decrease in nuclear pTyr105-PKM2 protein. These findings provide evidence for the non-canonical activity of PKM2 in cancer cell survival. Furthermore, they highlight the potential role of PKM2 as a future therapeutic target for duodenal and gastric cancer.

Cutaneous delivery of [1-(4-chloro-3-nitrobenzenesulfonyl)-1H-indol-3-yl]-methanol, an indole-3-carbinol derivative, mitigates psoriasiform lesion by blocking MAPK/NF-κB/AP-1 activation.

[1-(4-chloro-3-nitrobenzenesulfonyl)-1H-indol-3-yl]-methanol (CIM) has been used as a bioactive agent for inhibiting tumor growth and angiogenesis via mitogen-activated protein kinase (MAPK) and NF-κB blocking. The present work was undertaken to investigate the potential of CIM against psoriasis using imiquimod (IMQ)-stimulated psoriasis-like mouse and in vitro HaCaT keratinocytes as the models. We demonstrated that topical CIM treatment reduced IMQ-activated scaling, erythema, and barrier dysfunction. This compound also restrained the recruitment of neutrophils. The cytokines, including TNF-α, IL-1ß, IL-6, and IL-17 in psoriasiform skin, can be attenuated to normal baseline by CIM. Topically applied CIM can be easily delivered into skin based on the affinity with stratum corneum (SC) ceramides. IMQ intervention increased the permeability by 3-fold as compared to healthy skin. CIM ameliorated psoriatic lesion without incurring overt signs of irritation. Both TNF-α and IMQ were employed as the stimulators to activate HaCaT for reciprocal elucidation of the mechanism of action. CIM inhibited the overexpression of IL-1ß, IL-6, and IL-24 in HaCaT. CIM exerted anti-inflammatory activity by suppressing the phosphorylation of NF-κB and activator protein-1 (AP-1) through MAPK pathways. Our results indicate that CIM has potential as the antipsoriatic molecule. The detailed signaling pathways still need further investigation.

6-(7-nitro-2,1,3-benzoxadiazol-4-ylthio) hexanol: a promising new anticancer compound.

The 7-nitro-2,1,3-nitrobenzoxadiazole (NBD) derivatives are a series of compounds containing the NBD scaffold that are not glutathione (GSH) peptidomimetics, and result in a strong inhibition of glutathione S-transferases (GSTs). Growing evidences highlight their pivotal roles and outstanding anticancer activity in different tumor models. In particular, 6-(7-nitro-2,1,3-benzoxadiazol-4-ylthio) hexanol (NBDHEX) is extensively studied, which is a very efficient inhibitor of GSTP1-1. It triggers apoptosis in several tumor cell lines and this cytotoxic activity is observed at micro and submicromolar concentrations. Importantly, studies have shown that NBDHEX acts as an anticancer drug by inhibiting GSTs catalytic activity, avoiding inconvenience of the inhibitor extrusion from the cell by specific pumps and disrupting the interaction between the GSTP1-1 and key signaling effectors. Additionally, some researchers also have discovered that NBDHEX can act as late-phase autophagy inhibitor, which opens new opportunities to fully exploit its therapeutic potential. In this review, we summarize the advantages, anticancer mechanisms, and analogs of this compound, which will establish the basis on the usage of NBDHEX in clinical applications in future.

Selective cyclooxygenase-2 inhibitor NS-398 attenuates myocardial fibrosis in mice after myocardial infarction via Snail signaling pathway.

OBJECTIVE: The role of NS-398 in Snail pathway of myocardial cells in mice after myocardial infarction and its effect on myocardial fibrosis were investigated in this study. MATERIALS AND METHODS: C57BL/6 mice were selected to establish mouse models of myocardial infarction with permanent ligation of anterior descending branch and sham-operation models without ligation. After successful establishment of models, 30 mice were randomly divided into sham-operation group, myocardial infarction group and drug intervention group. The drug intervention group was treated with intraperitoneal injection of NS-398 (5 mg/kg) at 1 week after modeling for 3 weeks. The survival status of mice after operation was monitored, the cardiac function was detected via echocardiography, the collagen levels in heart tissue pathological sections were detected via Masson staining and Sirius red staining. Moreover, the expressions of Snail and type I collagen levels were detected via immunohistochemistry, and the Snail protein expression level and the activity and expression level of E-cadherin protein were detected via Western blotting. RESULTS: At 4 weeks after establishment of myocardial infarction model, the fibrosis reaction was obvious, and the cardiac function was decreased, accompanied with Snail activation. The administration of NS-398 for 3 weeks inhibited the Snail activity expression and significantly improved the fibrosis degree after infarction. However, it did not improve the cardiac function. Inhibiting Snail improved the fibrosis reaction after infarction, in which Snail/E-cadherin signaling pathway was involved. CONCLUSIONS: NS-398 improves the myocardial fibrosis in mice after myocardial infarction through inhibiting the Snail signaling pathway.

Tumor Cell Invasion Induced by Radiation in Balb/C Mouse is Prevented by the Cox-2 Inhibitor NS-398.

Radiation stimulates the expression of inflammatory mediators known to increase cancer cell invasion. Therefore, it is important to determine whether anti-inflammatory drugs can prevent this adverse effect of radiation. Since cyclooxygenase-2 (COX-2) is a central player in the inflammatory response, we performed studies to determine whether the COX-2 inhibitor NS-398 can reduce the radiation enhancement of cancer cell invasion. Thighs of Balb/c mice treated with NS-398 were irradiated with either daily fractions of 7.5 Gy for five consecutive days or a single 30 Gy dose prior to subcutaneous injection of nonirradiated MC7-L1 mammary cancer cells. Five weeks later, tumor invasion, blood vessel permeability and interstitial volumes were assessed using magnetic resonance imaging (MRI). Matrix metalloproteinase-2 (MMP-2) was measured in tissues by zymography at 21 days postirradiation. Cancer cell invasion in the mouse thighs was increased by 12-fold after fractionated irradiations (5 × 7.5 Gy) and by 17-fold after a single 30 Gy dose of radiation. This stimulation of cancer cell invasion was accompanied by a significant increase in the interstitial volume and a higher level of the protease MMP-2. NS-398 treatment largely prevented the stimulation of cancer cell invasion, which was associated with a reduction in interstitial volume in the irradiated thighs and a complete suppression of MMP-2 stimulation. In conclusion, this animal model using MC7-L1 cells demonstrates that radiation-induced cancer cell invasion can be largely prevented with the COX-2 inhibitor NS-398.

Cyclooxygenase-2 facilitates dengue virus replication and serves as a potential target for developing antiviral agents.

Cyclooxygenase-2 (COX-2) is one of the important mediators of inflammation in response to viral infection, and it contributes to viral replication, for example, cytomegalovirus or hepatitis C virus replication. The role of COX-2 in dengue virus (DENV) replication remains unclear. In the present study, we observed an increased level of COX-2 in patients with dengue fever compared with healthy donors. Consistent with the clinical data, an elevated level of COX-2 expression was also observed in DENV-infected ICR suckling mice. Using cell-based experiments, we revealed that DENV-2 infection significantly induced COX-2 expression and prostaglandin E2 (PGE2) production in human hepatoma Huh-7 cells. The exogenous expression of COX-2 or PGE2 treatment dose-dependently enhanced DENV-2 replication. In contrast, COX-2 gene silencing and catalytic inhibition sufficiently suppressed DENV-2 replication. In an ICR suckling mouse model, we identified that the COX-2 inhibitor NS398 protected mice from succumbing to life-threatening DENV-2 infection. By using COX-2 promoter-based analysis and specific inhibitors against signaling molecules, we identified that NF-κB and MAPK/JNK are critical factors for DENV-2-induced COX-2 expression and viral replication. Altogether, our results reveal that COX-2 is an important factor for DENV replication and can serve as a potential target for developing therapeutic agents against DENV infection.

NS-398 promotes pancreatic cancer cell invasion by CD147 and MMP-2 via the activation of P38.

The overexpression or abnormal activation of cyclo­oxygenase­2 (COX­2) has been reported in pancreatic cancer cells. NS­398, a selective inhibitor of COX­2, is unable to inhibit pancreatic cancer cell proliferation, as determined by a Cell Counting Kit 8 assay. However, it does increase cancer cell invasiveness, and therefore the invasiveness of the PANC­1 cells was determined, along with the activation of P38, which was assessed by western blotting. In the present study, to evaluate the mechanisms underlying the action of NS­398 in pancreatic cancer cells, PANC­1 cells were treated with NS­398, and the invasion signaling pathways of cluster of differentiation (CD)147­matrix metalloproteinase (MMP)­2 and mitogen­activated protein kinases were evaluated. The results showed that NS­398­induced the expression of CD147 and MMP­2 via the activation of P38, which was involved in antiproliferative activity and induced pancreatic cancer cell invasiveness. The PANC­1 cells were also co­treated with CD147 small interfering (si)RNA and NS­398, and it was found that the NS­398­induced activation of P38 was not inhibited by CD147 siRNA, however, the expression of MMP­2 was inhibited. CD147 siRNA inhibited the invasiveness of the pancreatic cancer cells induced by NS­398, but also restored NS­398­induced antiproliferative activity. These data indicated that P38 in the pancreatic cancer cells was non­specifically activated by NS­398. This activation induced the expression of CD147­MMP­2, opposed the antiproliferative activity of NS­398 and increased the invasiveness of the PANC­1 cells.

COX-2 inhibition attenuates lung injury induced by skeletal muscle ischemia reperfusion in rats.

BACKGROUND: Skeletal muscle ischemia reperfusion accounts for high morbidity and mortality, and cyclooxygenase (COX)-2 is implicated in causing muscle damage. Downregulation of aquaporin-1 (AQP-1) transmembrane protein is implicated in skeletal muscle ischemia reperfusion induced remote lung injury. The expression of COX-2 in lung tissue and the effect of COX-2 inhibition on AQP-1 expression and lung injury during skeletal muscle ischemia reperfusion are not known. We investigated the role of COX-2 in lung injury induced by skeletal muscle ischemia reperfusion in rats and evaluated the effects of NS-398, a specific COX-2 inhibitor. METHODS: Twenty-four Sprague Dawley rats were randomized into 4 groups: sham group (SM group), sham+NS-398 group (SN group), ischemia reperfusion group (IR group) and ischemia reperfusion+NS-398 group (IN group). Rats in the IR and IN groups were subjected to 3h of bilateral ischemia followed by 6h of reperfusion in hindlimbs, and intravenous NS-398 8 mg/kg was administered in the IN group. In the SM and SN groups, rubber bands were in place without inflation. At the end of reperfusion, myeloperoxidase (MPO) activity, COX-2 and AQP-1 protein expression in lung tissue, PGE2 metabolite (PGEM), tumor necrosis factor (TNF)-α and interleukin (IL)-1ß levels in bronchoalveolar lavage (BAL) fluid were assessed. Histological changes in lung and muscle tissues and wet/dry (W/D) ratio were also evaluated. RESULTS: MPO activity, COX-2 expression, W/D ratio in lung tissue, and PGEM, TNF-α and IL-1ß levels in BAL fluid were significantly increased, while AQP-1 protein expression downregulated in the IR group as compared to that in the SM group (P<0.05). These changes were remarkably mitigated in the IN group (P<0.05). NS-398 treatment also alleviated histological signs of lung and skeletal muscle injury. CONCLUSION: COX-2 protein expression was upregulated in lung tissue in response to skeletal muscle ischemia reperfusion. COX-2 inhibition may modulate pulmonary AQP-1 expression and attenuate lung injury.

The COX-2-Selective Antagonist (NS-398) Inhibits Choroidal Neovascularization and Subretinal Fibrosis.

Choroidal neovascularization (CNV) is an important pathologic component of neovascular age-related macular degeneration (AMD), and CNV lesions later develop into fibrous scars, which contribute to the loss of central vision. Nowadays, the precise molecular and cellular mechanisms underlying CNV and subretinal fibrosis have yet to be fully elucidated. Cyclooxygenase-2 (COX-2) has previously been implicated in angiogenesis and fibrosis. However, the role of COX-2 in the pathogenesis of CNV and subretinal fibrosis is poorly understood. The present study reveals several important findings concerning the relationship of COX-2 signaling with CNV and subretinal fibrosis. Experimental CNV lesions were attenuated by the administration of NS-398, a COX-2-selective antagonist. NS-398-induced CNV suppression was found to be mediated by the attenuation of macrophage infiltration and down-regulation of VEGF in the retinal pigment epithelium-choroid complex. Additionally, NS-398 attenuated subretinal fibrosis, in an experimental model of subretinal scarring observed in neovascular AMD, by down-regulation of TGF-ß2 in the retinal pigment epithelium-choroid complex. Moreover, we cultured mouse RPE cells and found that NS-398 decreased the secretion of VEGF and TGF-ß2 in mouse RPE cells. The results of the present study provide new findings regarding the molecular basis of CNV and subretinal fibrosis, and provide a proof-of-concept approach for the efficacy of COX-2 inhibition in treating subretinal fibrosis.

Inhibition of NarL of Mycobacterium Tuberculosis: an in silico approach.

Mycobacterium tuberculosis (MTB) consumes nitrate as the alternate mechanism of respiration in the absence of oxygen, thus increasing its survival and virulence during latent stage of tuberculosis infection. NarL is a nitrate/nitrite response transcriptional regulatory protein of two-component signal transduction system which regulates nitrate reductase and formate dehydrogenase for MTB adaptation to anaerobic condition. Phosphorylation by sensor kinase (NarX) is the primary mechanism behind the activation of NarL although many response regulators get activated by small molecule phospho-donors in the absence of sensor kinase. Virtual screening was performed using Autodock suite for the compounds from ZINC database against NarL and potential inhibitors was identified to inhibit the activation of NarL by affecting its phosphorylation. Molecular dynamics simulation studies predicted the stability of 1-{1-[(3-nitrophenyl) methyl] piperidin-2-yl} ethan-1-amine in the active site of NarL over 10 ns simulation. Phosphorylation of NarL by small molecule phospho-donors is also investigated in the present study. Here we suggest that nitro benzene - amine piperidine moiety can be an effective lead candidate for developing novel anti-tuberculosis drugs.

TCDD­induced chick cardiotoxicity is abolished by a selective cyclooxygenase­2 (COX­2) inhibitor NS398.

Halogenated aromatic hydrocarbons, including 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), are known to cause severe heart defects in avian species. However, the mechanism of TCDD-induced chick cardiovascular toxicity is unclear. In this study, we investigated cyclooxygenase-2 (COX-2) as a possible mechanism of TCDD-induced cardiotoxicity. Fertile chicken eggs were injected with TCDD and a COX-2 selective inhibitor, NS398, and we investigated chick heart failure on day 10. We found that the chick heart to body weight ratio and atrial natriuretic factor mRNA expression were increased, but this increase was abolished with treatment of NS398. In addition, the morphological abnormality of an enlarged ventricle resulting from TCDD exposure was also abolished with co-treatment of TCDD and NS398. Our results suggested that TCDD-induced chick heart defects are mediated via the nongenomic pathway and that they do not require the genomic pathway.