Upregulation Of Cyclooxygenase-2 Expression Research Articles

Immunohistochemical Investigation of Cyclooxygenase-2 Expression in Rabbit Uterine Adenocarcinoma and the Potential Use of COX-2 Inhibitors in Cancer Therapy.

Cyclooxygenase-2 (COX-2) is overexpressed in many human and animal cancers. Selective COX-2 inhibitors have shown antitumoral effects in tumors with a high expression of COX-2. This study evaluates (1) the expression of COX-2 in rabbit uterine adenocarcinomas, (2) the correlation between immunophenotypic expression and histopathological changes, and (3) the post-surgery response to therapy with COX-2 inhibitors. Forty rabbit uteri were divided into three groups: neoplastic, hyperplastic, and normal endometrium. A histological and immunohistochemical score was applied to investigate the tumor's grade and the COX-2 expression. By histological evaluation, 30 cases of endometrial adenocarcinoma, 5 cases of endometrial hyperplasia and 5 normal endometria were found. Of the six cases of endometrial adenocarcinoma with follow-up available, four received a post-surgical treatment with meloxicam and two were treated by surgery alone. The survival time of the animals treated with meloxicam was longer than that observed in the untreated animals. A statistically significant difference in COX-2 IHS was observed between non-neoplastic endometrium and adenocarcinoma. The progressive increase in COX-2 expression from normal epithelium to carcinoma suggests that upregulation of COX-2 expression may play a role in tumor initiation and progression. Our findings suggest the possible use of COX-2 inhibitors in treating uterine adenocarcinoma in rabbits. Further study will be needed to confirm this hypothesis.

Targeting MEK/COX-2 axis improve immunotherapy efficacy in dMMR colorectal cancer with PIK3CA overexpression.

PIK3CA mutation or overexpression is associated with immunotherapy resistance in multiple cancer types, but is also paradoxically associated with benefit of COX-2 inhibition on patient survival of colorectal cancer (CRC) with mismatch repair deficiency (dMMR). This study examined whether and how PIK3CA status affected COX-2-mediated tumor inflammation and immunotherapy response of dMMR CRC. Murine colon cancer cells MC38, CT26, and CT26-Mlh1-KO were used to construct PIK3CA knockdown and overexpression models to mimic dMMR CRC with PIK3CA dysregulation, and xenograft models were used to evaluate how PIK3CA regulate COX-2 expression, CD8+ T cells infiltration, tumor growth, and therapy response to anti-PD-L1 treatment using immunocompetent mice. Western blot was carried out to delineate the signaling pathways in human and mouse cancer cells, and immunohistochemical analysis together with bioinformatics analysis using human patient samples. PIK3CA upregulates COX-2 expression through MEK/ERK signaling pathway independent of AKT signaling to promote tumor inflammation and immunosuppression. PIK3CA knockdown profoundly reduced CT26 tumor growth in a CD8+ T cell-dependent manner, while PIK3CA overexpression significantly inhibited CD8+ T cells infiltration and promoted tumor growth. Furthermore, MEK or COX-2 inhibition augmented the anti-tumor activity of anti-PD-L1 immunotherapy on dMMR CRC mouse models, accompanied with increased CD8+ T cells infiltration and activated tumor microenvironment. Our results identified that the PIK3CA hyperactivation in dMMR CRC upregulated COX-2 through MEK signaling, which inhibited CD8+ T cells infiltration and promoted tumor growth, together led to immunotherapy resistance. COX-2 or MEK inhibition may relieve therapy resistance and promote therapy efficacy of anti-PD-1/PD-L1 immunotherapy for treating dMMR CRC with PIK3CA overexpression or activating mutation.

Regulatory action of PGRMC1 on cyclic AMP-mediated COX2 expression in human endometrial cells

Human endometrial stromal cells (ESCs) undergo differentiation, known as decidualization, and endometrial epithelial cells mature around the embryo implantation stage. In the uterus, cyclooxygenase 2 (COX2), the rate-limiting enzyme that produces prostaglandin E2, is expressed in endometrial stromal and epithelial cells, and promotes decidualization of the former cells. Our recent study demonstrated that progesterone receptor membrane component 1 (PGRMC1) is downregulated during decidualization and may be involved in cellular senescence associated with decidualization via the transcription factor forkhead box protein O1 (FOXO1). Therefore, we investigated the role of PGRMC1 in COX2 expression during differentiation and maturation of endometrial stromal and epithelial cells. Inhibition or knockdown of PGRMC1 significantly enhanced differentiation stimuli-induced COX2 expression in both cell types. However, this COX2 expression was suppressed by FOXO1 knockdown or nuclear factor-kappa B (NF-κB) inhibition. Silencing of COX2 expression inhibited PGRMC1 knockdown-induced expression of decidual markers in ESCs. Thus, PGRMC1 may be linked to FOXO1- and NF-κB-mediated COX2 expression in endometrial cells. Taken together, our data suggest that downregulation of PGRMC1 expression facilitates differentiation of endometrial cells, i.e., decidualization and glandular maturation, via upregulation of COX2 expression.

Interleukin-1 increases cyclooxygenase-2 expression and prostaglandin E2 production in human granulosa-lutein cell via nuclear factor kappa B/P65 and extracellular signal-regulated kinase 1/2 signaling pathways

A multitude of cytokines have been reported to participate in the folliculogenesis process in female. Interleukin-1 (IL-1), belonging to interleukin family, is originally identified as an important immune factor involved in inflammation response. Besides the immunity system, IL-1 is also expressed in reproductive system. However, the role of IL-1 in regulating ovarian follicle function remains to be elucidated. In the current study, using the primary human granulosa-lutein (hGL) and immortalized human granulosa-like tumor cell line (KGN) models, we demonstrated that both IL-1α and IL-1β increased prostaglandin E2 (PGE2) production via upregulating its cyclooxygenase (COX) enzyme COX-2 expression in human granulosa cells. Mechanistically, IL-1α and IL-1β treatment activated nuclear factor kappa B (NF-κB) signaling pathway. Using the specific siRNA to knock down endogenous gene expression, we found that the inhibition of p65 expression abolished IL-1α and IL-1β-induced upregulation of COX-2 expression whereas knockdown of p50 and p52 had no effect. Moreover, our results also showed that IL-1α and IL-1β promoted the nuclear translocation of p65. ChIP assay demonstrated the transcriptional regulation of p65 on COX-2 expression. Additionally, we also found that IL-1α and IL-1β could activate the extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway. The inhibition of ERK1/2 signaling pathway activation reversed IL-1α and IL-1β-induced upregulation of COX-2 expression. Our findings shed light on the cellular and molecular mechanisms by which IL-1 modulates the COX-2 expression through NF-κB/P65 and ERK1/2 signaling pathways in human granulosa cells.

TNF-α/IL-1β-licensed hADSCs alleviate cholestatic liver injury and fibrosis in mice via COX-2/PGE2 pathway

BackgroundAdipose tissue-derived stem cell (ADSC) transplantation has been shown to be effective for the management of severe liver disorders. Preactivation of ADSCs enhanced their therapeutic efficacy. However, these effects have not yet been examined in relation to cholestatic liver injury.MethodsIn the present study, a cholestatic liver injury model was established by bile duct ligation (BDL) in male C57BL/6 mice. Human ADSCs (hADSCs) with or without tumor necrosis factor-alpha (TNF-α) and interleukin-1beta (IL-1β) pretreatment were administrated into the mice via tail vein injections. The efficacy of hADSCs on BDL-induced liver injury was assessed by histological staining, real-time quantitative PCR (RT-qPCR), Western blot, and enzyme-linked immune sorbent assay (ELISA). In vitro, the effects of hADSC conditioned medium on the activation of hepatic stellate cells (HSCs) were investigated. Small interfering RNA (siRNA) was used to knock down cyclooxygenase-2 (COX-2) in hADSCs.ResultsTNF-α/IL-1β preconditioning could downregulate immunogenic gene expression and enhance the engraftment efficiency of hADSCs. Compared to control hADSCs (C-hADSCs), TNF-α/IL-1β-pretreated hADSCs (P-hADSCs) significantly alleviated BDL-induced liver injury, as demonstrated by reduced hepatic cell death, attenuated infiltration of Ly6G + neutrophils, and decreased expression of pro-inflammatory cytokines TNF-α, IL-1β, C-X-C motif chemokine ligand 1 (CXCL1), and C-X-C motif chemokine ligand 2 (CXCL2). Moreover, P-hADSCs significantly delayed the development of BDL-induced liver fibrosis. In vitro, conditioned medium from P-hADSCs significantly inhibited HSC activation compared to that from C-hADSCs. Mechanistically, TNF-α/IL-1β upregulated COX-2 expression and increased prostaglandin E2 (PGE2) secretion. The blockage of COX-2 by siRNA transfection reversed the benefits of P-hADSCs for PGE2 production, HSC activation, and liver fibrosis progression.ConclusionIn conclusion, our results suggest that TNF-α/IL-1β pretreatment enhances the efficacy of hADSCs in mice with cholestatic liver injury, partially through the COX-2/PGE2 pathway.

A PRECLINICAL MODEL OF STENOTIC CROHN’S DISEASE FOR THE STUDY OF MECHANISMS OF MOTILITY DYSFUNCTION IN IBD

Abstract BACKGROUND AND AIMS Motility dysfunction is present in patients with stenotic Crohn’s disease (CD) and contributes to cramps, diarrhea and constipation. However, mechanisms for motility dysfunction in CD are incompletely understood. Mechanical stress, i.e. inflammatory infiltration, edema, stenosis, and distention, is commonly encountered in CD. We tested the hypothesis in a rat model of stenotic CD that mechanical stress-induced expression of mechano-sensitive genes such as cyclo-oxygenase-2 (COX-2) may account for motility dysfunction in the inflammation site and the mechanically distended site prior to inflammation. ANIMAL MODEL AND METHODS Rat model of CD-like colitis was induced by intracolonic instillation of TNBS 65 mg/kg in 250 µL of 40% ethanol. Control rats were treated with intracolonic saline instillation. When rats were fed with regular pellet food, instillation of TNBS led to localized transmural inflammation with stenosis in the instillation site (site I) and lumen distention in the colon segment proximal to inflammation (site P). However, when rats were fed exclusively with liquid diet, inflammation-associated stenosis and mechanical distention was eliminated. Rats were euthanized by 7 days. RESULTS 1) Compared to controls, COX-2 mRNA expression was increased by 13.1(± 2.5)-fold in site I and 16.6(±4.3)-fold in the mechanically distended site P, but not in the non-distended site D. This data indicates a mechanosensitive mechanism in COX-2 expression. If mechanical distention in CD was prevented by feeding rats exclusively with clear liquid diet, the increase of COX-2 mRNA expression was attenuated in sites I and P. Further investigation showed that increased expression of COX-2 occurs mainly in the colonic smooth muscle cells (SMC) of the distended colon. 2) We found that COX-2 expression was robustly induced by mechanical stretch (18% static stretch) in vitro in rat colonic smooth muscle cells (SMC). 3) Inflammation led to significant suppression of colon circular muscle contractility not only in site I but also in distended site P of CD-like rats. Muscle contractility in site D was not significantly affected by inflammation. Moreover, clear liquid diet treatment significantly improved muscle contractility in sites P and I. 4) To determine the role of COX-2 in smooth muscle dysfunction in the CD model, COX-2 inhibitor NS-398 (5 mg/kg, i.p. daily) was administered in control and CD rats. We found that NS-398 significantly improved muscle contractility in CD rats in sites P and I. CONCLUSIONS Our study found that up-regulation of COX-2 expression in stenotic CD-like colitis is dependent on mechanical stress. COX-2 inhibitor improved colon smooth muscle contractility in colitis. Thus, mechanosensitive expression of COX-2 may play a critical role in smooth muscle dysfunction and dysmotility in CD.

Clozapine Suppresses the Gene Expression and the Production of Cytokines and Up-Regulates Cyclooxygenase 2 mRNA in Human Astroglial Cells.

Schizophrenia (SCZ) is a chronic neurodevelopmental psychotic disorder. The immune system and neuroinflammation seem to play a central role in the pathophysiology of SCZ. Clozapine is an effective atypical antipsychotic used for treatment-resistant SCZ. Life-threatening side effects, such as myocarditis, limit its use. We investigated the immunomodulatory effects of clozapine in an astroglial model of neuroinflammation. We thus assessed the effect of clozapine on the production of inflammatory mediators in human-derived astroglial (A172) cells, stimulated with a cytokine mix (TNFα, IL-1β, IFNγ). RT-PCR and ELISA analyses demonstrated that clozapine suppressed gene expression and production of TNFα, IL-1β and IL-8 and increased COX2 mRNA 24 h after stimulation. Clozapine inhibited Akt phosphorylation induced by the cytokine mix at 10 min and 40 min, as assessed by Western blot analysis with anti-pT308Akt antibody. Pretreatment with the Akt inhibitor MK-2206 increased COX2 gene expression in cytokine-stimulated cells, suggesting that Akt inhibition may be involved in COX2 gene expression upregulation. Clozapine may possess dual beneficial effects: inhibiting astroglial production of proinflammatory cytokines, thus attenuating neuroinflammation, and upregulating COX2 expression that may be relevant to improvement of neural functioning while accounting for some of its detrimental effects. Patients with TRS and neuroinflammatory markers may benefit particularly from clozapine treatment.

Contribution of cyclooxygenase-2 overexpression to enhancement in tonically active glutamatergic inputs to the rostral ventrolateral medulla in hypertension.

Cyclooxygenase (COX) is critical in regulating cardiovascular function, but its role involved in the central control of blood pressure (BP) is uncovered. The tonic glutamatergic inputs to the rostral ventrolateral medulla (RVLM) are enhanced in hypertension. Here, the present study was designed to investigate the effect and mechanism of central COX on tonic glutamatergic inputs to the RVLM and BP regulation. Wistar-Kyoto (WKY) rats and spontaneous hypertensive rats (SHRs) received RVLM microinjection of adeno-associated viral vectors to promote or inhibit the COX2 expression were subjected to subsequent experiments. Glutamate level and glutaminase expression were detected by ELISA and western blot, respectively. The function of tonic glutamatergic inputs was assessed by BP response to microinjection of the glutamate receptor antagonist into the RVLM. PC12 cells were used to detect the underlying signal pathway. The RVLM COX2 expression and prostaglandin E2 level were significant higher in SHRs than in WKY rats. Overexpression of COX2 in the RVLM produced an increase in basal BP, RVLM glutamate level, and glutaminase expression in WKY rats, while they were significantly reduced by interfering with COX2 expression in SHRs. Microinjections of the glutamate receptor antagonist into the RVLM produced a significant BP decrease in WKY rats with COX2 overexpression pretreatment. Furthermore, the increased levels of BP, glutamate content, and glutaminase activity in the RVLM evoked by central infusion of angiotensin II were attenuated in COX2 knockout mice. It was also found that prostaglandin E2 increased supernatant glutamate level and phosphorylation of signal transducer and activator of transcription 3 in PC12 cells. Our findings suggest that upregulated COX2 expression enhances the tonically active glutamatergic inputs to the RVLM, which is associated with cardiovascular regulation in hypertension.

COX-2 upregulation by tumour cells post-chemotherapy fuels the immune evasive dark side of cancer inflammation.

Cytotoxic therapies, such as chemotherapy and radiotherapy, are mainstays of cancer treatment for both early and unresectable, advanced disease. In addition to debulking the tumour mass through direct killing of proliferating tumour cells, these treatments can promote tumour control via immune-stimulating effects. Nonetheless, chemoresistance and tumour relapse remain huge clinical problems, suggesting that induction of anti-cancer immunity post-cytotoxic therapy is often weak, not durable and/or overcome by immune evasive mechanisms. In our recent study (Nat Commun 13:2063), we demonstrate that cancer cell-intrinsic activation of the cyclooxygenase (COX)-2/prostaglandin E2 (PGE2) pathway post-chemotherapy treatment is a prevalent phenomenon which profoundly alters the inflammatory properties of the treated cancer cells. Of particular translational relevance, our findings support a model whereby upregulation of COX-2 expression and activity post-chemotherapy impairs the efficacy of the combination of PD-1 blockade and chemotherapy. Accordingly, pharmacological inhibition of COX-2 with celecoxib, an anti-inflammatory drug already used clinically, unleashed tumour control in preclinical models when given alongside chemoimmunotherapy combinations.

353P Loss of CDX2 and high COX2 (PTGS2) expression in stage IV colorectal cancer

Lack of expression of the tumor suppressor CDX2 is associated with stage II/III colorectal cancer (CRC) poor outcomes. Its potential prognostic and predictive values in metastatic CRC (mCRC), and correlation with other potential biomarkers are of great interest. Overexpression of the PTGS2 gene encoding cyclooxygenase 2 (COX2) has shown a significantly direct association with advanced CRC stages. Reduced CDX2 in CRC has been suggested to enhance NF-κB-mediated inflammatory response, upregulating COX2 expression.

Role of p53 methylation in manganese-induced cyclooxygenase-2 expression in BV2 microglial cells

Manganese (Mn) is an essential cofactor for many enzymes and plays an important role in normal growth and development. However, excess exposure to manganese (Mn) may be an important environmental factor leading to neurodegeneration. The overexpression of microglial cyclooxygenase-2 (COX-2) plays a key role in neuroinflammation in neurodegenerative diseases. The existing data suggest that Mn can induce neuroinflammation by up-regulating COX-2 expression. However, the mechanisms involved in Mn-induced microglial COX-2 up-regulation remain to be determined. The aim of this study was to investigate the role of p53 in Mn-induced COX-2 expression in microglial cells. The results showed that Mn exposure induced the up-regulation of COX-2 and inhibited the expression of p53 in BV2 microglial cells. The addition of p53 activator and the over-expression of p53 blocked the expression of COX-2 and prostaglandin E2 (PGE2), a COX-2 downstream effector, induced by Mn. Further, Mn increased the methylation of p53 DNA in microglia, while the addition of demethylation reagent 5-Aza-dC enhanced the expression of p53 but decreased the expression of COX-2. These results suggested that Mn may inhibit p53 expression through induction of DNA methylation, which can further induce the expression of COX-2 in microglial cells.

Modulatory Effects of Estradiol and Its Mixtures with Ligands of GPER and PPAR on MAPK and PI3K/Akt Signaling Pathways and Tumorigenic Factors in Mouse Testis Explants and Mouse Tumor Leydig Cells.

The present study was designed to evaluate how estradiol alone or in combination with G protein-coupled estrogen receptor (GPER) agonists and GPER and peroxisome proliferator-activated receptor (PPAR) antagonists alter the expression of tumor growth factor β (TGF-β), cyclooxygenase-2 (COX-2), hypoxia inducible factor 1-alpha (HIF-1α), and vascular endothelial growth factor (VEGF) in mouse testis explants and MA-10 mouse tumor Leydig cells. In order to define the hormone-associated signaling pathway, the expression of MAPK and PI3K/Akt was also examined. Tissue explants and cells were treated with estradiol as well as GPER agonist (ICI 182,780), GPER antagonist (G-15), PPARα antagonist (GW6471), and PPARγ antagonist (T00709072) in various combinations. First, we showed that in testis explants GPER and PPARα expressions were activated by the GPER agonist and estradiol (either alone or in mixtures), whereas PPARγ expression was activated only by GPER agonist. Second, increased TGF-β expression and decreased COX-2 expression were found in all experimental groups of testicular explants and MA-10 cells, except for up-regulated COX-2 expression in estradiol-treated cells, compared to respective controls. Third, estradiol treatment led to elevated expression of HIF-1α and VEGF, while their lower levels versus control were noted in the remaining groups of explants. Finally, we demonstrated the up-regulation of MAPK and PI3Kp85/Akt expressions in estradiol-treated groups of both ex vivo and in vitro models, whereas estradiol in mixtures with compounds of agonistic or antagonistic properties either up-regulated or down-regulated signaling kinase expression levels. Our results suggest that a balanced estrogen level and its action together with proper GPER and PPAR signaling play a key role in the maintenance of testis homeostasis. Moreover, changes in TGF-β and COX-2 expressions (that disrupted estrogen pathway) as well as disturbed GPER-PPAR signaling observed after estradiol treatment may be involved in testicular tumorigenesis.

Vitamin D stimulates miR-26b-5p to inhibit placental COX-2 expression in preeclampsia

Vitamin D insufficiency or deficiency during pregnancy has been associated with an increased risk of preeclampsia. Increased placental cyclooxygenase-2 (COX-2) activity was proposed to contribute to the inflammatory response in preeclampsia. This study was to investigate if vitamin D can benefit preeclampsia by inhibiting placental COX-2 expression. Placenta tissues were obtained from 40 pregnant women (23 normotensive and 17 preeclampsia). miR-26b-5p expression was assessed by quantitative PCR. Vitamin D receptor (VDR) expression and COX-2 expression were determined by immunostaining and Western blot. HTR-8/SVneo trophoblastic cells were cultured in vitro to test anti-inflammatory effects of vitamin D in placental trophoblasts treated with oxidative stress inducer CoCl2. 1,25(OH)2D3 was used as bioactive vitamin D. Our results showed that reduced VDR and miR-26b-5p expression, but increased COX-2 expression, was observed in the placentas from women with preeclampsia compared to those from normotensive pregnant women. Transient overexpression of miR-26b-5p attenuated the upregulation of COX-2 expression and prostaglandin E2 (PGE2) production induced by CoCl2 in placental trophoblasts. 1,25(OH)2D3 treatment inhibited CoCl2-induced upregulation of COX-2 in placental trophoblasts. Moreover, miR-26b-5p expression were significantly upregulated in cells treated with 1,25(OH)2D3, but not in cells transfected with VDR siRNA. Conclusively, downregulation of VDR and miR-26b-5p expression was associated with upregulation of COX-2 expression in the placentas from women with preeclampsia. 1,25(OH)2D3 could promote miR-26b-5p expression which in turn inhibited COX-2 expression and PGE2 formation in placental trophoblasts. The finding of anti-inflammatory property by vitamin D through promotion of VDR/miR-26b-5p expression provides significant evidence that downregulation of vitamin D/VDR signaling could contribute to increased inflammatory response in preeclampsia.

NSP2 Is Important for Highly Pathogenic Porcine Reproductive and Respiratory Syndrome Virus to Trigger High Fever-Related COX-2-PGE2 Pathway in Pigs.

In 2006, atypical porcine reproductive and respiratory syndrome (PRRS) caused by a highly pathogenic PRRSV (HP-PRRSV) strain broke out in China. Atypical PRRS is characterized by extremely high fever and high mortality in pigs of all ages. Prostaglandin E2 (PGE2) derived from arachidonic acid through the activation of the rate-limiting enzyme cyclooxygenase type 1/2 (COX-1/2) plays an important role in fever. Here, we showed that HP-PRRSV infection increased PGE2 production in microglia via COX-2 up-regulation depending on the activation of MEK1-ERK1/2-C/EBPβ signaling pathways. Then, we screened HP-PRRSV proteins and demonstrated that HP-PRRSV nonstructural protein 2 (NSP2) activated MEK1-ERK1/2-C/EBPβ signaling pathways by interacting with 14-3-3ζ to promote COX-2 expression, leading to PGE2 production. Furthermore, we identified that the amino acid residues 500-596 and 658-777 in HP-PRRSV NSP2 were essential to up-regulate COX-2 expression and PGE2 production. Finally, we made mutant HP-PRRS viruses with the deletion of residues 500-596 and/or 658-777, and found out that these viruses had impaired ability to up-regulate COX-2 and PGE2 production in vitro and in vivo. Importantly, pigs infected with the mutant viruses had relieved fever, clinical symptoms, and mortality. These data might help us understand the molecular mechanisms underlying the high fever and provide clues for the development of HP-PRRSV attenuated vaccines.

Composition and Acute Inflammatory Response from Tetraponera rufonigra Venom on RAW 264.7 Macrophage Cells.

Tetraponera rufonigra (Arboreal Bicoloured Ant) venom induces pain, inflammation, and anaphylaxis in people and has an increased incident in Southeast Asia regions. The bioactive components and mechanism of action of the ant venom are still limited. The aim of this research was to identify the protein composition and inflammatory process of the ant venom by using RAW 264.7 macrophage cells. The major venom proteins are composed of 5’ nucleotidase, prolyl endopeptidase-like, aminopeptidase N, trypsin-3, venom protein, and phospholipase A2 (PLA2). The venom showed PLA2 activity and represented 0.46 μg of PLA2 bee venom equivalent/μg crude venom protein. The venom induced cytotoxic in a dose- and time-dependent manner with IC20 approximately at 4.01 µg/mL. The increased levels of COX-2 and PGE2 were observed after 1 h of treatment correlating with an upregulation of COX-2 expression. Moreover, the level of mPGES-1 expression was obviously increased after 12 h of venom induction. Hence, our results suggested that the induction of COX-2/mPGEs-1 pathway could be a direct pathway for the ant venom-induced inflammation.

Impact of zinc oxide nanoparticles and thymoquinone in Ehrlich ascites carcinoma induced in mice.

The field of nanotechnology offers great opportunities for cancer therapy. This study aimed to compare the therapeutic impact of Zn oxide nanoparticles (ZnO NPs) and thymoquinone (TQ) alone or as cotherapy in Ehrlich ascites carcinoma (EAC) induced in mice. This study was performed on 75 female albino mice divided intoGroup I: EAC-bearing control group, Group II: EAC treated with TQ, Group III: EAC treated with low-dose ZnO NPs, Group IV: EAC treated with high-dose ZnO NPs, Group V: EAC treated with TQ and low-dose ZnO NPs. All groups were subjected to measurement of cell viability, ascites fluid volume, Bcl2 protein expression by Western blot analysis, cyclooxygenase 2 (COX2) gene expression by a real-time polymerase chain reaction, enzyme-linked immunosorbent assay levels of Beclin 1, interferon γ (INFγ), interleukin 13 (IL-13), and estimation of Zn concentrations in EAC cells and liver homogenate to evaluate its toxicity. Cotherapy has an efficient anticancer effect by enhancing apoptosis and autophagy, resulting in reducing tumor cell viability and ascites fluid volume together with downregulation of Bcl2 protein expression. This cotherapy increases Beclin 1 and INFγ and decreases IL-13. ZnO NPs upregulate COX2 expression, whereas TQ downregulates its expression. High-dose ZnO NPs have more toxic effects on liver enzymes. Using TQ together with ZnO NPs can eliminate ZnO NPs liver toxicity. The cotherapy has an efficient anticancer effect by enhancing apoptosis and autophagy. High-dose ZnO NPs have more toxic effects on liver enzymes. Using TQ together with ZnO NPs can eliminate ZnO NP liver toxicity.

Ferritinophagy-Mediated Ferroptosis Involved in Paraquat-Induced Neurotoxicity of Dopaminergic Neurons: Implication for Neurotoxicity in PD.

Parkinson's disease (PD) is a progressive nervous system disorder. Until now, the molecular mechanism of its occurrence is not fully understood. Paraquat (PQ) was identified as a neurotoxicant and is linked to increased PD risk and PD-like neuropathology. Ferroptosis is recognized as a new form of regulated cell death. Here, we revealed a new underlying mechanism by which ferritinophagy-mediated ferroptosis is involved in PD induced by PQ. The effect of PQ on movement injury in mice was investigated by the bar fatigue and pole-climbing test. SH-SY5Y human neuroblastoma cells were used to evaluate the mechanism of ferroptosis. Our results showed that PQ induced movement injury by causing the decrease in tyrosine hydroxylase in mice. In vitro, PQ significantly caused the iron accumulation in cytoplasm and mitochondria through ferritinophagy pathway induced by NCOA4. Iron overload initiated lipid peroxidation through 12Lox, further inducing ferroptosis by producing lipid ROS. PQ downregulated SLC7A11 and GPX4 expression and upregulated Cox2 expression significantly, which were important markers in ferroptosis. Fer-1, an inhibitor of ferroptosis, could significantly ameliorate the ferroptosis induced by PQ. Meanwhile, Bcl2, Bax, and p-38 were involved in apoptosis induced by PQ. In conclusion, ferritinophagy-mediated ferroptosis pathway played an important role in PD occurrence. Bcl2/Bax and P-p38/p38 pathways mediated the cross-talk between ferroptosis and apoptosis induced by PQ. These data further demonstrated the complexity of PD occurrence. The inhibition of the ferroptosis and apoptosis together may be a new strategy for the prevention of neurotoxicity or PD in the future.

MicroRNA-30a-3p acts as a tumor suppressor in MHCC-97H hepatocellular carcinoma cells by targeting COX-2.

MicroRNAs (miRNAs) are small, noncoding RNAs which can bind to target mRNAs and regulate gene expression. Increasing evidences suggest that miRNAs play an important role in driving hepatocellular carcinoma (HCC) progression by regulating tumor cell proliferation, apoptosis, invasion, and migration. In this study, we demonstrated that the expression of microRNA-30a-3p (miR-30a-3p) was reduced in HCC cell lines in comparison to immortalized liver cell line, LO2. Augmented miR-30a-3p level markedly inhibited MHCC-97H cell growth, migration and invasion in vitro. MiR-30a-3p was also found to inhibit tumor growth in vivo using tumor-bearing mice. Mechanismly, COX-2 was discovered to be a direct and functional target of miR-30a-3p in MHCC-97H cells. Raised miR-30a-3p expression reduced the transcriptional level of COX-2 in MHCC-97H cells, while genetically upregulated COX-2 expression was able to reverse the function of miR-30a-3p-mediated suppression of MHCC-97H cells growth, migration and invasion. In addition, we found that using a COX-2 inhibitor, celecoxib, could enhance the anti-metastatic role of miR-30a-3p in MHCC-97H cells. Lastly, we found that decreased COX-2 protein level affected PGE2 production, leading to lower Bcl-2, Caspase-3, MMP2 and MMP9 expression but higher Bax and E-cadherin expression, which in turn culminated in higher rates of cell death and lower rates of cell migration. Taken together, our findings demonstrate that miR-30a-3p could be a target for the treatment of hepatocellular carcinoma cells progression.

KSHV G-protein coupled receptor vGPCR oncogenic signaling upregulation of Cyclooxygenase-2 expression mediates angiogenesis and tumorigenesis in Kaposi's sarcoma.

Kaposi’s sarcoma-associated herpesvirus (KSHV) vGPCR is a constitutively active G protein-coupled receptor that subverts proliferative and inflammatory signaling pathways to induce cell transformation in Kaposi’s sarcoma. Cyclooxygenase-2 (COX-2) is an inflammatory mediator that plays a key regulatory role in the activation of tumor angiogenesis. Using two different transformed mouse models and tumorigenic full KSHV genome-bearing cells, including KSHV-Bac16 based mutant system with a vGPCR deletion, we demostrate that vGPCR upregulates COX-2 expression and activity, signaling through selective MAPK cascades. We show that vGPCR expression triggers signaling pathways that upregulate COX-2 levels due to a dual effect upon both its gene promoter region and, in mature mRNA, the 3’UTR region that control mRNA stability. Both events are mediated by signaling through ERK1/2 MAPK pathway. Inhibition of COX-2 in vGPCR-transformed cells impairs vGPCR-driven angiogenesis and treatment with the COX-2-selective inhibitory drug Celecoxib produces a significant decrease in tumor growth, pointing to COX-2 activity as critical for vGPCR oncogenicity in vivo and indicating that COX-2-mediated angiogenesis could play a role in KS tumorigenesis. These results, along with the overexpression of COX-2 in KS lesions, define COX-2 as a potential target for the prevention and treatment of KSHV-oncogenesis.

Pathophysiology of Intracranial Aneurysms: COX-2 Expression, Iron Deposition in Aneurysm Wall, and Correlation With Magnetic Resonance Imaging.

The pathophysiology of development, growth, and rupture of intracranial aneurysms (IAs) is only partly understood. Cyclooxygenase 2 (COX-2) converts arachidonic acid to prostaglandin H2, which, in turn, is isomerized to prostaglandin E2. In the human body, COX-2 plays an essential role in inflammatory pathways. This explorative study aimed to investigate COX-2 expression in the wall of IAs and its correlation to image features in clinical (1.0T, 1.5T, and 3.0T) magnetic resonance imaging (MRI) and ultra-high-field 7T MRI. The study group comprised 40 patients with partly thrombosed saccular IAs. The cohort included 17 ruptured- and 24 unruptured IAs, which had all been treated microsurgically. Formaldehyde-fixed paraffin-embedded samples were immunohistochemically stained with a monoclonal antibody against COX-2 (Dako, Santa Clara, CA; Clone: CX-294). We correlated Perls Prussian blue staining, MRI, and clinical data with immunohistochemistry, analyzed using the Trainable Weka Segmentation algorithm. Aneurysm dome size ranged between 2 and 67 mm. The proportion of COX-2 positive cells ranged between 3.54% to 85.09%. An upregulated COX-2 expression correlated with increasing IA dome size (P=0.047). Furthermore, there was a tendency of higher COX-2 expression in most ruptured IAs (P=0.064). At all field strengths, MRI shows wall hypointensities due to iron deposition correlating with COX-2 expression (P=0.022). Iron deposition and COX-2 expression in IAs walls correlate with signal hypointensity in MRI, which might, therefore, serve as a biomarker for IA instability. Furthermore, as COX-2 was also expressed in small unruptured IAs, it could be a potential target for specific medical treatment.