Cyclooxygenase 2 polymorphism and colorectal cancer:-765G>C variant modifies risk associated with smoking and body mass index

AIM： To explore whether cyclooxygenase 2 （COX-2） -765G〉C polymorphism is associated with susceptibility of colorectal cancer （CRC） and to evaluate the risk of colorectal cancer in relation to environmental exposures and polymorphism. METHODS： We conducted a case-control study of 137 patients with colorectal cancer and 199 cancerfree controls in northeast China. Multivariate logistic regression analysis was performed to calculate the adjusted odds ratio （OR） and 95% confidence interval （95% CI）. RESULTS： The -765G〉C polymorphism was not independently associated with CRC risk. However, risk associated with the polymorphism differed by smoking and body mass index （BMI）. Smoking and BMI associated risks were stronger among those with -765GG genotype, showing that smokers had a 2.682-fold greater risk of CRC than nonsmokers （51/43 vs 68/126, P = 0.006）. Compared to those with a normal body mass index （BMI 18.5-22.9）, those with overweight （BMI 23-24.9） had a 3.909-fold higher risk of CRC （OR = 3.909, 95% CI = 2.081-7.344; P 〈 0.001）, while those with obesity （BMI 〉 25） had a 2.031- fold higher risk of CRC （OR = 1.107, 95% CI = 1.107-3.726; P = 0.022）. is not associated with an increased risk of CRC, -765GG genotype appears to be related to an increased risk in the presence of smoking and higher BMI.

Spatiotemporal expression of inducible nitric oxide synthase and cyclooxygenase 2 in the spinal cord during early stage sciatic nerve crush injury

BACKGROUND： Previous studies have shown that inducible nitric oxide synthase （iNOS） and cyclooxygenase 2 （COX-2） participate in inflammatory immune responses and neuropathic pain following peripheral nerve injury. However, few reports have addressed time-dependent expression of iNOS and COX-2 following peripheral nerve injury. OBJECTIVE： To investigate spatiotemporal expression of iNOS and COX-2 during early stage sciatic nerve crush injury.DESIGN, TIME AND SETTING： The randomized, controlled, animal experiment was performed at the Laboratory of Applied Anatomy, Department of Human Anatomy and Neurobiology, Central South University, China from September 2006 to September 2007.MATERIALS： Mouse anti-rat iNOS monoclonal antibody and goat anti-rat COX-2 monoclonal antibody （Transduction Laboratory, USA）, as well as biotinylated rabbit anti-mouse lgG and biotinylated rabbit anti-goat IgG （Santa Cruz Biotechnology, USA） were used in the present study.METHODS： A total of 48 healthy, adult, Sprague Dawley rats were randomly assigned to three groups. In the model group （n = 32）, crush injury to the right sciatic nerve was established using an artery clamp. The model group was further assigned to four subgroups according to survival time （6,12, 24, and 72 hours）, respectively （n = 8）. Sham surgery （n = 8） and normal control （n = 8） groups were also established.MAIN OUTCOME MEASURES： iNOS and COX-2 expression was detected in the L4-6 spinal cord with immunohistochemistry. Gray values of iNOS- and COX-2-postive cells in the anterior horn and posterior horn of spinal cord, as well as quantification of iNOS- and COX-2-positive cells in the anterior horn of spinal cord, were measured.RESULTS： iNOS and COX-2 expression gradually increased in the anterior horn and posterior horn of the spinal cord on the damaged side over time from 6 hours following sciatic nerve injury （P〈0.05） and peaked at 72 hours. Simultaneously, the number of iNOS- and COX-2-positive cells similarly increased in the anterior horn of spinal cord on the damaged side （P〈 0.05）.CONCLUSION： iNOS and COX-2 expression increased in the spinal cord during early stage sciatic nerve crush, which suggested that iNOS and COX-2 participate in occurrence and development of inflammatory immune responses following peripheral nerve injury.

Expression and Significance of Cyclooxygenase 2 Gene in Lung Cancer

To study the expression of cyclooxygenase 2 (COX-2) gene and its relationship with clinicopathological characteristics of lung cancer, expression of the COX-2 mRNA was evaluated by reverse transcription polymerase chain reaction (RT-PCR) in cancerous tissues and paired adjacent non-cancerous tissues from 56 patients and benign lesions from 12 patients. Our results showed that expression of COX-2 gene was detected in a significantly greater proportion of cancerous tissues (60.7 %) than adjacent noncancerous tissues (10.7 %, P<0.01) and benign lesions (3/12, P<0.05). Expression of COX-2 gene was higher in adenocarcinoma than in squamous carcinoma (P<0.01). There was no significant relationship between COX-2 gene expression and patients' age, sex, histological type of tumors, differentiation degree and TNM stages (P>0.05). The up-regulation of COX-2 gene in lung cancer tissues especially in adenocarcinoma suggested that COX-2 may play a role in the lung carcinogenesis and COX-2 gene may serve as a potential therapeutic target in lung cancer.

Expression of inducible nitric oxide synthase and cyclooxygenase-2 in pancreatic adenocarcinoma:Correlation with microvessel density

AIM:Cydooxygenases (COX) are key enzymes for conversion of arachidonic acid to prostaglandins.Nitric oxide synthase (NOS) is the enzyme responsible for formation of nitric oxide. Both have constitutive and inducible isoforms.The inducible isoforms (iNOS and COX-2) are of great interest as regulators of tumor angiogenesis,tumorigenesis and inflammatory processes.This study was to clarify their role in pancreatic adenocarcinomas. METHODS:We investigated the immunohistochemical iNOS and COX-2 expression in 40 pancreatic ductal adenocardnomas of different grade and stage.The results were compared with microvessel density and dinicopathological data. RESULTS:Twenty-one (52.5%) of the cases showed iNOS expression,15 (37.5%) of the cases were positive for COX-2. The immunoreaction was heterogeneously distributed within the tumors.Staining intensity was different between the tumors.No correlation between iNOS and COX-2 expression was seen.There was no relationship with microvessel density. However,iNOS positive tumors developed more often distant metastases and the more malignant tumors showed a higher COX-2 expression.There was no correlation with other clinicopathological data. CONCLUSION:Approximately half of the cases expressed iNOS and COX-2.These two enzymes do not seem to be the key step in angiogenesis or carcinogenesis of pancreatic adenocarcinomas.Due to a low prevalence of COX-2 expression,chemoprevention of pancreatic carcinomas by COX-2 inhibitors can only achieve a limited success.

Aspirin inhibits the proliferation of tobacco-related esophageal squamous carcinomas cell lines through cyclooxygenase 2 pathway

Background Cigarette smoking has been verified as the risk factor of esophageal squamous cell carcinoma （ESCC）. Overexpression of cyclooxygenase 2 （COX-2） is shown in ESCC. The objective of this study was to investigate the effects of cigarette smoking ethanol extract （EE） on the proliferation of the human ESCC cell lines, and to explore the correlation between the proliferation rate of human ESCC cell lines and the expression pattern of COX-2. Whether aspirin can inhibit the proliferation of the ESCC cell lines pretreated with EE, and regulate the mRNA expression levels of COX-2 are also examined. Methods Two human ESCC cell lines were selected. EC109 was poorly differentiated and EC9706 was highly differentiated. EC109 and EC9706 were treated with EE and aspirin for different time course. The cell growth of ESCC was measured by MTT reduction assay and the expression of COX-2 was measured by RT-PCR and Western blot analysis. Results EE promoted the proliferation of EC109 and EC9706 in dose- and time-dependent manners. In the concentration range （10-100 pg/ml for EE） and in the time range （24-72 hours） after addition of EE, the cell proliferation was prominent in an up-scaled manner respectively. Aspirin could inhibit the proliferation of cell lines EC109 and EC9706 pretreated with EE for 5 hours, in a dose-dependent manner. In the concentration range （0.5-8.0 mmot/L for aspirin）, the cell growth inhibition was prominent in an up-scaled manner accordingly （P〈0.05）. The effect of EE on cell proliferation was correlated with the up-regulation of COX-2 gene. However, the cell growth inhibition of aspirin was correlated with the down-regulation of COX-2 gene. Conclusions EE can stimulate the proliferation of human ESCC cell lines EC109 and EC9706, most likely through up-regulating the expression of COX-2. Aspirin can inhibit the proliferation of ESCC cell lines induced by EE, which suggests it may be advantageous in the chemoprevention and therapy of human tobacco-related ESCC. And its effect is likely to be related with modulating COX-2 activity.

Effects of electroacupuncture on uterine prostaglandin F2α,cyclooxygenase 2 and nuclear factorκB in rats with primary dysmenorrhea

Objective:To observe the effects of electroacupuncture(EA)on uterine prostaglandin F2α(PGF2α),cyclooxygenase 2(COX-2)and nuclear factorκB(NF-κB)in rats with primary dysmenorrhea(PD)and to discuss the possible mechanism in EA intervening PD.Methods:Forty Sprague-Dawley female rats were randomly divided into a blank group,a model group,an EA group and an ibuprofen group,with 10 rats in each group.The PD model was established using estradiol benzoate combined with oxytocin in the model group,EA group and ibuprofen group.At the same time of modeling,rats in the EA group were given EA at Guanyuan(CV 4)and Sanyinjiao(SP 6)once a day for 20 min each time for 10 consecutive days.Ibuprofen was intragastrically administered once a day for 10 consecutive days in the ibuprofen group.The same amount of normal saline was intragastrically administered once a day for 10 consecutive days in the blank group and model group.The number of writhing of rats in each group within 30 min was compared on the 11th day just after the interventions.The uterine homogenate supernatant was separated and the PGF2αlevel was detected by enzyme-linked immunosorbent assay.Western blot was applied for the detection of the expression levels of COX-2,phospho-NF-κB p65 and NF-κB p65 proteins in uterine tissues.Results:Compared with the blank group,the number of writhing in the model group increased significantly(P<0.01),and the expression levels of PGF2α,COX-2,phospho-NF-κB p65 and NF-κB p65 proteins in uterine tissues were significantly increased(all P<0.01).Compared with the model group,the number of writhing in the EA group and ibuprofen group were significantly reduced(both P<0.01),and the expression levels of PGF2αand COX-2 protein in uterine tissues were significantly reduced(both P<0.01).Compared with the model group,the phospho-NF-κB p65 level in uterine tissues in the EA group was significantly reduced(P<0.01).Compared with the ibuprofen group,the phospho-NF-κB p65 level in the EA group was significantly reduced(P<0.01).Conclusion:The mechanism of EA for PD rats may be related to inhibiting the phosphorylation of NF-κB and reducing the levels of COX-2 and PGF2αin uterine tissues.

Effect of Propyl Gallate on Activity of Cyclooxygenase 1 and 2 in Mice's Peritoneal Macrophages*

Objective: To investigate the effect of Red Peony 801 (propyl gallate,PrG) on cyclooxygenase (COX) activity in murine peritoneal macrophages. Methods: A screening model for COX inhibitors in vitro based on murine peritoneal macrophages was used. COX-1 activity was reflected by the level of 6-ketoprostaglandin F1α(6-keto-PGF1α) in supernatants of cultured macrophages which were stimulated with calcium ionophore A23187 for a short-term, while COX-2 activity was reflected by the level of prostaglandin E2 (PGE2) in supernatants of cultured macrophages which were stimulated with lipopolysaccharide (LPS) for a long-term. Results: PrG did not affect A23187-induced, COX-1-derived 6-keto-PGF1α synthesis at the concentrations of 1×10-5, 5×10-6 mol/L (P>0.05), but enhanced 6-keto-PGF1α synthesis at the concentrations of 1×10-6, 5×10-7, 1×10-7 mol/L (P<0.01) in vitro, and showed a good dose-dependent manner. It inhibited LPS-induced, COX-2-derived PGE2 synthesis at the concentrations of 1×10-5,1×10-6 mol/L (P< 0. 05). Conclusion: Within the range of 1×10-5 to 1×10-7 mol/L, PrG activated COX-1 at lower concentrations and inhibited COX-2 at higher concentrations in murine peritoneal macrophages.

Tolerance of neurite outgrowth to Rho kinase inhibitors decreased by cyclooxygenase-2 inhibitor

In this study, PC12 Adh cells and Neuro-2a cells were treated with Rho-associated kinase inhibitors （Y27632 and Fasudil）, a cyclooxygenase-1 selective inhibitor （SC560）, and a cyclooxygenase-2 inhibitor （NS398）. We found that these cells became tolerant to Rho-associated kinase inhibitors, as neurite outgrowth induced by these inhibitors diminished following more than 3 days of exposure in either cell line. The proteins cyclooxygenase-2 and cytosolic prostaglandin E synthetase were upregulated at day 3. NS398 decreased the tolerance to neurite outgrowth induction in both cell lines, whereas SC560 had almost no effect. These findings indicate that cells become tolerant to neurite outgrowth induced by Rho-associated kinase inhibitors, this is at least partly associated with upregulation of proteins involved in the cyclooxygenase-2 pathway, and cyclooxygenases-2 inhibition prevents this tolerance.

Quantitative analysis of cyclooxygenase 2 in the posterior longitudinal ligament of cervical spondylotic myelopathy

Background Cervical spondylotic myelopathy （CSM）, in part, results from degeneration of the posterior longitudinal ligament （PLL）, which mechanically compresses the spinal cord. Much research was done on the ossification of PLL, but not concerning the non-ossifying degeneration of cervical PLL. The degeneration of cervical PLL may be related to inflammation. The aim of this study was to elucidate the pathological features of the PLL and the role of cyclooxygenase 2 （COX-2） in the degeneration of the PLL in CSM. Methods A total of 23 PLL specimens were collected during surgery from patients with CSM for the histological and immunohistochemical （type II collagen and Ki-67） study. For the control group 14 cervical PLL autopsy specimens were investigated in the same manner, mRNA expression of COX-2 was quantitatively measured by real-time reverse transcription-polymerase chain reaction （RT-PCR） from 18 PLL specimens of patients with CSM and 18 PLL specimens of autopsy cases. Immunohistochemistry was used to evaluate the cellular location of COX-2 in PLL. Results A distinct amount of fibrotic area, chondrometaplastic tissue and calcification were found in the PLL of the patient group, compared with the control group. Type II collagen was apparent around chondrometaplastic cells. Ki-67 positive reaction was less than 5%. A COX-2 positive reaction was found in 9 of the patient specimens （39.1%） in which the COX-2 was released from vascular endothelial cells in the PLL. However, such reactions were not found in the control group. Real-time PCR showed that the mRNA expression level of COX-2 in the patient group was significantly higher than that in the control group （P〈0.01）. Conclusions Chondrometaplastic tissue producing type II collagen was identified as the most predominant pathological feature in the degenerative PLL. The higher expression of COX-2 might be related to degeneration of the PLL in CSM.

Effects of Electroacupuncture Intervention on Expression of Cyclooxygenase 2 and Microglia in Spinal Cord in Rat Model of Neuropathic Pain

Objective： To investigate the effect of electroacupuncture（EA） treatment on the expression of cyclooxygenase（COX） 2 and microglia in spinal cord by using rat model of neuropathic pain, and to probe into the relationship between COX 2 and microglia. Methods： The rats were randomly divided into 6 groups, including normal control group, model group, sham group, EA 1 group（distant acupoints ＋ local acupoints）, EA 2 group（local acupoints）, and EA 3 group（distant acupoints）. Thermal withdrawal latencies were evaluated at 1 day preoperatively and 3, 5 and 7 days postoperatively. At 7 days postoperatively, the spinal COX 2 m RNA was detected by reverse-transcription polymerase chain reaction. Double immunofluorescent staining technology was applied to screen and verify the relationship between altered COX 2 and microglia. Results： Compared with the model group, thermal withdrawal latencies increased after EA treatment（P〈0.01）. The expressions of COX 2 m RNA were up-regulated in spinal cord of rat on day 7 after surgery（P〈0.05）. Compared with the model group, EA stimulation（EA 1 and EA 2 groups） reversed the up-regulation of COX 2 m RNA expression（P〈0.05）. EA 1 and EA 2 groups might have better treatment effect compared with the EA 3 group. Fluorescent images displayed COX 2 and microglia expressed at common areas. Conclusions： EA was effective in analgesic and anti-inflammatory. EA has decreased the expression of spinal COX 2 m RNA in the trend of the therapeutic effect of ＂distant acupoints ＋ local acupoints＂, and ＂local acupoints＂ intervention may be superior to that of ＂distant acupoints＂ intervention. Microglia may be related to the formation of COX 2.

Comparative analysis of clinicopathological correlations of cyclooxygenase-2 expression in resectable pancreatic cancer

AIM:To perform a comparative analysis of clinicopathological correlations of cyclooxygenase2 (COX2) expression in pancreatic cancer, examined by monoclonal and polyclonal antibodies.METHODS: The COX2 expression in 85 resection specimens of pancreatic ductal adenocarcinoma was immunohistochemically examined using both monoclonal and polyclonal antibodies. The final immunoscores were obtained by multiplying the percentage of positive cells with the numeric score reflecting the staining intensity.COX2 expression levels were classified into three categories (0, 1+, and 2+) and the clinicopathological correlations were statistically evaluated and analyzed.RESULTS: The positive tumor expression rates of COX2 were 80.5% using monoclonal antibody and 69.4% using polyclonal antibody. In the KaplanMeier analysis, no significant correlations were found between levels of COX2 expression and overall survival (OS), but trends to longer OS were found in COX2 negative cases using monoclonal antibody. Significantly longer disease free survival was revealed in COX2 negative cases using monoclonal antibody (P = 0.019). No correlations between COX2 expression levels and grade (G), tumor (T) status and nodal (N) status were demonstrated. Low histological grade showed a strong association with a longer OS (P < 0.001). Correlation of survival and T status revealed a shorter OS in T3 tumors, but the results reached only marginal statistical significance (P = 0.070). In the multivariate Cox proportional hazards regression model, histological grade, T and N status remained valuable predictors of a worse survival with borderline significance for T [hazards ratio (HR) = 4.18 for G (if G = 3, P < 0.001); HR = 1.64 for T (if T = 3, P = 0.065); HR = 2.53 for N (if N = 1, P = 0.006)]. Higher grade, T or N status was associated with a worse OS. CONCLUSION: The immunohistochemically assessed level of COX2 expression does not seem to represent a valuable independent prognostic factor and is not superior to the conventional prognostic factors.

Relationship between expression and distribution of cyclooxygenase-2 and bcl-2 in human gastric adenocarcinoma

AIM: To explore expression and distribution features of COX-2 and bcl-2 in human gastric adenocarcinoma tissues and to study its biological significance.METHODS: Totally 36 human gastric carcinoma samples were enrolled in this study (cardiac adenocarcinoma 16 cases, distal gastric adenocarcinoma 20 cases). The expressions of COX-2 and bcl-2 in cancerous tissues and corresponding para-cancerous tissues were investigated by immunohistochemistry using COX-2 polyclonal antibody and bcl-2 monoclonal antibody. The normal gastric mucosa tissues were used as control.RESULTS: The expressions of COX-2 and bcl-2 in gastric carcinoma were significantly higher than that in the paracancerous tissues (77.8% vs 47.2%, P＜0.01, 80.56% vs 58.33%, P＜0.05). The expression of COX-2 in cardiac adenocarcinoma was remarkably higher than that in the distal gastric carcinoma (93.8% vs 65.0%, P＜0.01). The expression of COX-2 was mainly localized in the cytoplasm of tumor cells and partly in the nucleus. There is a transition of the COX-2 cytoplasmic positivity to nucleic in tumor cells with the increase of gastric carcinoma pathological grade. Interstitial macrophages, fibroblasts and vascular endothelial cells also expressed COX-2. The tissues with higher expression of COX-2 also expressed high level of bcl-2 protein.CONCLUSION: Abnormal expression pattern of COX-2within the tissues of human gastric cancer is correlated with tumor location and lymph node metastasis. COX-2may regulate expression of apoptosis suppressor gene (bcl-2) through interaction of tumor cells and stromal cells and play an important role in the generation and development of tumors, which will be of great help in developing new methods for antitumor therapy.

Effect of Nimesulide on proliferation and apoptosis of human hepatoma SMMC-7721 cells

AIM: Cyclooxygenase-2 (COX-2) has been suggested to be associated with carcinogenesis. We sought to investigate the effect of the selective COX-2 inhibitor, Nimesulide on proliferation and apoptosis of SMMC-7721 human hepatoma cells.METHODS: This study was carried out on the culture of hepatic carcinoma SMMC-7721 cell line. Various concentrations of Nimesulide (0, 200 micromol/L, 300 micromol/L, 400 micromol/L) were added and incubated. Cell proliferation was detected with MTT colorimetric assay, cell apoptosis by electron microscopy, flow cytometry and TUNEL.RESULTS: Nimesulide could significantly inhibit SMMC-7721 cells proliferation dose-dependent and in a dependent manner compared with that of the control group. The duration lowest inhibition rate produced by Nimesulide in SMMC-7721 cells was 19.06%, the highest inhibition rate was 58.49%. After incubation with Nimesulide for 72 h, the most highest apoptosis rate and apoptosis index of SMMC-7721 cells comparing with those of the control were 21.20%+/-1.62% vs 2.24%+/-0.26% and 21.23+/-1.78 vs 2.01+/-0.23 (P【0.05). CONCLUSION:The selective COX-2 inhibitor, Nimesulide can inhibit the proliferation of SMMC-7721 cells and increase apoptosis rate and apoptosis index of SMMC-7721 cells. The apoptosis rate and the apoptosis index are dose-dependent. Under electron microscope SMMC-7721 cells incubated with 300 micromol and 400 micromol Nimesulide show apoptotic characteristics. With the clarification of the mechanism of selective COX-2 inhibitors, These COX-2 selective inhibitors can become the choice of prevention and treatment of cancers.

Selective COX-2 inhibitor,NS-398,suppresses cellular proliferation in human hepatocellular carcinoma cell lines via cell cycle arrest

AIM: To investigate the growth inhibitory mechanism of NS-398, a selective cyclooxygenase-2 (COX-2) inhibitor, in two hepatocellular carcinoma (HCC) cell lines (HepG2 and Huh7). METHODS: HepG2 and Huh7 cells were treated with NS-398. Its effects on cell viability, cell proliferation, cell cycles, and gene expression were respectively evaluated by water-soluble tetrazolium salt (WST-1) assay, 4’-6-diamidino-2-phenylindole (DAPI) staining, flow cytometer analysis, and Western blotting, with dimethyl sulfoxide (DMSO) as positive control. RESULTS: NS-398 showed dose- and time-dependent growth-inhibitory effects on the two cell lines. Proliferating cell nuclear antigen (PCNA) expressions in HepG2 and Huh7 cells, particularly in Huh7 cells were inhibited in a time- and dose-independent manner. NS-398 caused cell cycle arrest in the G1 phase with cell accumulation in the sub-G1 phase in HepG2 and Huh7 cell lines. No evidence of apoptosis was observed in two cell lines. CONCLUSION: NS-398 reduces cell proliferation by inducing cell cycle arrest in HepG2 and Huh7 cell lines, and COX-2 inhibitors may have potent chemoprevention effects on human hepatocellular carcinoma.

Extract of buckwheat sprouts scavenges oxidation and inhibits pro-inflammatory mediators in lipopolysaccharide-stimulated macrophages (RAW264.7)

OBJECTIVE： Buckwheat has been considered as a potential source of nutraceutical components on the world market of probiotic foodstuffs. The purpose of this study was to evaluate the effects of tartary buckwheat （Fagopyrum tataricum） sprouts on oxidation and pro-inflammatory mediators. METHODS： The anti-oxidant effects of buckwheat extract （BWE） and rutin were evaluated by using 1,1-diphenyl-2-picrylhydrazyl （DPPH）-and nitric oxide （NO）-scavenging activities, serum peroxidation and chelating assays. Lipopolysaccharide （LPS）-stimulated RAW264.7 cells were used to evaluate anti-inflammatory activities of buckwheat and rutin. NO production in LPS- stimulated RAW264.7 cells was determined by using Griess reagent. The expressions of inducible nitric oxide synthase （iNOS）, cyclooxygenase-2 （COX-2）, nuclear factor-kappa B （NF-κB） p65 subunit in cytosolic and nuclear portions were determined by Western blot analysis. Also, the production of inflammatory cytokines interleukin-6 （IL-6） and tumor necrosis factor-α （TNF-α） was determined by enzyme-linked immunosorbent assay. RESULTS： Inhibitory concentration 50 values for DPPH- and NO-scavenging activities of BWE were 24.97 and 72.54 μg/mL respectively. BWE inhibited serum oxidation and possessed chelating activity. Furthermore, BWE inhibited IL-6 and TNF-a production in LPS-stimulated RAW264.7 cells. Also, BWE inhibited iNOS and COX-2 expression and NF-KB p65 translocation. CONCLUSION： Buckwheat sprouts possessed strong antioxidant activity and inhibited production of pro-inflammatory mediators in the applied model systems. Thus, buckwheat can be suggested to be beneficial in inflammatory diseases by inhibiting the free radicals and inflammatory mediators.

COX-2 in liver,from regeneration to hepatocarcinogenesis:What we have learned from animal models?

The use of animals lacking genes or expressing genes under the control of cell-specific promoters has signifi cantly increased our knowledge of the genetic and molecular basis of physiopathology,allowing testing of functional hypotheses and validation of biochemical and pharmacologic approaches in order to understand cell function.However,with unexpected frequency,gene knockout animals and,more commonly,animal models of transgenesis give experimental support to even opposite conclusions on gene function.Here we summarize what we learned on the role of cyclooxygenase 2(COX-2) in liver and revise the results obtained in 3 independent models of mice expressing a COX-2 transgene specifi cally in the hepatocyte.Upon challenge with pro-inflammatory stimuli,the animals behave very differently,some transgenic models having a protective effect but others enhancing the injury.In addition,one transgene exerts differential effects on normal liver physiology depending on the transgenic animal model used.

Thymoquinone suppresses migration of Lo Vo human colon cancer cells by reducing prostaglandin E2 induced COX-2 activation

AIM To identify potential anti-cancer constituents in natural extracts that inhibit cancer cell growth and migration. METHODS Our experiments used high dose thymoquinone (TQ) as an inhibitor to arrest LoVo (a human colon adenocarcinoma cell line) cancer cell growth, which was detected by cell proliferation assay and immunoblotting assay. Low dose TQ did not significantly reduce LoVo cancer cell growth. Cyclooxygenase 2 (COX-2) is an enzyme that is involved in the conversion of arachidonic acid into prostaglandin E2 (PGE2) in humans. PGE2 can promote COX-2 protein expression and tumor cell proliferation and was used as a control. RESULTS Our results showed that 20 mu mol/L TQ significantly reduced human LoVo colon cancer cell proliferation. TQ treatment reduced the levels of p-PI3K, p-Akt, p-GSK3 beta, and beta-catenin and thereby inhibited the downstream COX-2 expression. Results also showed that the reduction in COX-2 expression resulted in a reduction in PGE2 levels and the suppression of EP2 and EP4 activation. Further analysis showed that TG treatment inhibited the nuclear translocation of beta-catenin in LoVo cancer cells. The levels of the cofactors LEF-1 and TCF-4 were also decreased in the nucleus following TQ treatment in a dose-dependent manner. Treatment with low dose TQ inhibited the COX-2 expression at the transcriptional level and the regulation of COX-2 expression efficiently reduced LoVo cell migration. The results were further verified in vivo by confirming the effects of TQ and/or PGE2 using tumor xenografts in nude mice. CONCLUSION TQ inhibits LoVo cancer cell growth and migration, and this result highlights the therapeutic advantage of using TQ in combination therapy against colorectal cancer.

Effects of melatonin on the expression of iNOS and COX-2 in rat models of colitis

AIM: To investigate the effects of melatonin (MT) on the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in rat models of colitis.METHODS: Healthy adult Sprague-Dawlay (SD) rats of both sexes, weighing 280±30 g, were employed in the present study. The rat models of colitis were induced by either acetic acid or 2,4,6-trinitrobenzene sulfonic acid (TNBS) enemas. The experimental animals were randomly divided into melatonin treatment and model control group that were intracolicly treated daily with melatonin at doses of 2.5, 5.0, 10.0 mg.kg-1 and equal amount of saline respectively from 24 h following induction of colitis in rats inflicted with acetic acid enema and the seventh day in rats with TNBS to the end of study. A normal control group of rats treated with neither acetic acid nor TNBS but saline enema was also included in the study. On the 28th day of the experiment, the rat colon mucosal damage index (CDMI) was calculated, and the colonic prostaglandin E2(PGE2), nitric oxide (NO), as well as the iNOS and COX-2expression were also determined biochemically or immunohistochemically.RESULTS: CDMI increased to 2.87±0.64 and 3.12±1.12respectively in rats treated with acetic acid and TNBS enema,which was in accordance with the significantly elevated colonic NO and PGE2 contents, as well as the up-regulated colonic iNOS and COX-2 expression in both of the two rat models of colitis. With treatment by melatonin at the doses of 5.0 and 10.0 mg@kg-1, CDMI in both models of rat colitis was significantly decreased (P＜0.05-0.01), which accorded synchronously and unanimously with the reduced colonic NO and PGE2 content, as well as the down-regulated expression of colonic iNOS and COX-2.CONCLUSION: Melatonin has a protective effect on colonic injury induced by both acetic acid and TNBS enemas, which is probably via a mechanism of local inhibition of iNOS and COX-2 expression in colonic mucosa.

Value of COX-2 and HER-2 in Judging Condition and Prognosis in Non-Small Cell Lung Cancer Patients

OBJECTIVE To investigate the expressions of cyclooxygenase 2 （COX-2） and human epidermal growth factor receptor-2 （HER-2） in non-small cell lung cancer （NSCLC） and their clinical significance in identifying the progression and prognosis of the NSCLC patients. METHODS Immunohistochemical indirect method was used to detect the expressions of the COX-2 and HER-2 protein in 54 NSCLC specimens, 16 paraneoplastic specimens, and 10 normal tissue specimens. RESULTS The positive rates of COX-2 and HER-2 protein expressions were respectively 75.9% and 40.7% in the NSCLC specimens, 25% and 12.5% in the paraneoplastic specimens, and 0 in the normal tissue. The COX-2 protein expression in lung cancer （LC） was not only related to the smoking habit of the patients and histological grades of LC, but also to the TNM stages, and lymphatic metastasis （P 〈 0.05）. HER-2 protein expression closely correlated to the pathologic types, histological grades, TNM stages, and lymphatic metastasis （P 〈 0.05）. The result of univariate analysis showed that all the histological grades, TNM stages, lymphatic metastasis, and expressions of COX-2/HER-2 correlated to the prognosis of NSCLC patients （mean of P value 〈 0.01）. The multivariate survival analysis indicated that there were signi.cant di.erences in comparison of the survival time between the COX-2 （＋＋/＋＋＋） /HER-2 （＋＋/＋＋＋） and the COX-2 （-/＋）/HER-2 （-/＋） groups （P〈 0.001）, suggesting the COX-2/HER-2 was a negative prognostic factor. CONCLUSION COX-2 and HER-2 are valuable in identifying the progression of NSCLC and predicting the prognosis of NSCLC patients. COX-2 and HER-2 are useful for judging the NSCLC patient＇s condition, and are of great value to the decision of NSCLC prognosis.

环氧化酶-2和血管内皮生长因子C表达与喉癌淋巴管转移

环氧化酶-2(cyclooxygenase-2,COX-2)是前列腺素合成的关键酶,在头颈鳞状细胞癌(简称鳞癌)等多种恶性肿瘤中表达上调,并与肿瘤发生和发展有关。淋巴管转移是喉鳞癌最常见的转移方式,血管内皮生长因子C(vascular endothelial growth factor C,VEGF-C)