Root canal contamination or exposure to lipopolysaccharide differentially modulate prostaglandin E 2 and leukotriene B 4 signaling in apical periodontitis

Abstract Purpose To evaluate the kinetics of apical periodontitis development in vivo , induced either by contamination of the root canals by microorganisms from the oral cavity or by inoculation of bacterial lipopolysaccharide (LPS) and the regulation of major enzymes and receptors involved in the arachidonic acid metabolism. Methodology Apical periodontitis was induced in C57BL6 mice (n=96), by root canal exposure to oral cavity (n=48 teeth) or inoculation of LPS (10 µL of a suspension of 0.1 µg/µL) from E. coli into the root canals (n= 48 teeth). Healthy teeth were used as control (n=48 teeth). After 7, 14, 21 and 28 days the animals were euthanized and tissues removed for histopathological and qRT-PCR analyses. Histological analysis data were analyzed using two-way ANOVA followed by Sidak's test, and qRT-PCR data using two-way ANOVA followed by Tukey's test (α=0.05). Results Contamination by microorganisms led to the development of apical periodontitis, characterized by the recruitment of inflammatory cells and bone tissue resorption, whereas inoculation of LPS induced inflammatory cells recruitment without bone resorption. Both stimuli induced mRNA expression for cyclooxygenase-2 and 5-lipoxygenase enzymes. Expression of prostaglandin E 2 and leukotriene B 4 cell surface receptors were more stimulated by LPS. Regarding nuclear peroxisome proliferator-activated receptors (PPAR), oral contamination induced the synthesis of mRNA for PPARδ, differently from inoculation of LPS, that induced PPARα and PPARγ expression. Conclusions Contamination of the root canals by microorganisms from oral cavity induced the development of apical periodontitis differently than by inoculation with LPS, characterized by less bone loss than the first model. Regardless of the model used, it was found a local increase in the synthesis of mRNA for the enzymes 5-lipoxygenase and cyclooxygenase-2 of the arachidonic acid metabolism, as well as in the surface and nuclear receptors for the lipid mediators prostaglandin E2 and leukotriene B4.

Immunoexpression of TS, p53, COX2, EGFR, MSH6 and MLH1 biomarkers and its correlation with degree of differentiation, tumor staging and prognostic factors in colorectal adenocarcinoma: a retrospective longitudinal study

ABSTRACT BACKGROUND: There are cases of colorectal tumors that, although small, show more aggressive evolution than large tumors. This motivated us to study whether there are any proteins capable of alerting about these changes. The aim here was to correlate the immunoexpression of the TS, p53, COX2, EGFR, MSH6 and MLH1 biomarkers in tumors in patients with colorectal adenocarcinoma, with the degree of cell differentiation, tumor staging and clinical-pathological prognostic factors. DESIGN AND SETTING: Retrospective observational study at a public tertiary-level hospital. METHODS: We analyzed tissue-microarray paraffin blocks of tumor tissues that had been resected from 107 patients. We used Fisher's exact test to study associations between tumor differentiation/staging and the immunoexpression of biomarkers. We also used Kaplan-Meier estimation, the log-rank test and the adjusted Cox regression model to investigate the patients' overall survival (in months) according to biomarkers and disease-free interval. RESULTS: The degree of tumor differentiation and tumor staging were not associated with the biomarkers, except in cases of patients in stages III or IV, in which there was a correlation with MLH1 expression (P=0.021). Patient survival and disease-free interval were not associated with the biomarkers. CONCLUSION: There were no associations between the degree of tumor differentiation, staging, length of survival or disease-free interval and the immunoexpression of the TS, p53, COX2, EGFR or MSH6 tumor markers. In advanced cases of colorectal adenocarcinoma (stages III and IV), there was a higher percentage of MLH1-negative results.

Periapical bone response to bacterial lipopolysaccharide is shifted upon cyclooxygenase blockage

Abstract Objectives: Infection, inflammation and bone resorption are closely related events in apical periodontitis development. Therefore, we sought to investigate the role of cyclooxygenase (COX) in osteoclastogenesis and bone metabolism signaling in periapical bone tissue after bacterial lipopolysaccharide (LPS) inoculation into root canals. Methodology: Seventy two C57BL/6 mice had the root canals of the first molars inoculated with a solution containing LPS from E. coli (1.0 mg/mL) and received selective (celecoxib) or non-selective (indomethacin) COX-2 inhibitor. After 7, 14, 21 and 28 days the animals were euthanized and the tissues removed for total RNA extraction. Evaluation of gene expression was performed by qRT-PCR. Statistical analysis was performed using analysis of variance (ANOVA) followed by post-tests (α=0.05). Results: LPS induced expression of mRNA for COX-2 (Ptgs2) and PGE2 receptors (Ptger1, Ptger3 and Ptger4), indicating that cyclooxygenase is involved in periapical response to LPS. A signaling that favours bone resorption was observed because Tnfsf11 (RANKL), Vegfa, Ctsk, Mmp9, Cd36, Icam, Vcam1, Nfkb1 and Sox9 were upregulated in response to LPS. Indomethacin and celecoxib differentially modulated expression of osteoclastogenic and other bone metabolism genes: celecoxib downregulated Igf1r, Ctsk, Mmp9, Cd36, Icam1, Nfkb1, Smad3, Sox9, Csf3, Vcam1 and Itga3 whereas indomethacin inhibited Tgfbr1, Igf1r, Ctsk, Mmp9, Sox9, Cd36 and Icam1. Conclusions: We demonstrated that gene expression for COX-2 and PGE2 receptors was upregulated after LPS inoculation into the root canals. Additionally, early administration of indomethacin and celecoxib (NSAIDs) inhibited osteoclastogenic signaling. The relevance of the cyclooxygenase pathway in apical periodontitis was shown by a wide modulation in the expression of genes involved in both bone catabolism and anabolism.

Wnt-5a-regulated miR-101b controls COX2 expression in hippocampal neurons

BACKGROUND: Wnt-5a is a member of the WNT family of secreted lipoglycoproteins, whose expression increases during development; moreover, Wnt-5a plays a key role in synaptic structure and function in the adult nervous system. However, the mechanism underlying these effects is still elusive. MicroRNAs (miRNAs) are a family of small non-coding RNAs that control the gene expression of their targets through hybridization with complementary sequences in the 3' UTR, thereby inhibiting the translation of the target proteins. Several evidences indicate that the miRNAs are actively involved in the regulation of neuronal function. RESULTS: In the present study, we examined whether Wnt-5a modulates the levels of miRNAs in hippocampal neurons. Using PCR arrays, we identified a set of miRNAs that respond to Wnt-5a treatment. One of the most affected miRNAs was miR-101b, which targets cyclooxygenase-2 (COX2), an inducible enzyme that converts arachidonic acid to prostanoids, and has been involved in the injury/inflammatory response, and more recently in neuronal plasticity. Consistent with the Wnt-5a regulation of miR-101b, this Wnt ligand regulates COX2 expression in a time-dependent manner in cultured hippocampal neurons. CONCLUSION: The biological processes induced by Wnt-5a in hippocampal neurons, involve the regulation of several miRNAs including miR-101b, which has the capacity to regulate several targets, including COX-2 in the central nervous system

Preventive effect of Ligularia fischeri on inhibition of nitric oxide in lipopolysaccharide-stimulated RAW 264. 7 macrophages depending on cooking method

BACKGROUND: Ligularia fischeri (common name Gomchwi) is known for its pharmaceutical properties and used in the treatment of jaundice, scarlet-fever, rheumatoidal arthritis, and hepatic diseases; however, little is known about its anti-inflammatory effect. In this study the influence of blanching and pan-frying on the anti-inflammatory activity of Ligularia fischeri (LF) was evaluated. RESULTS: Fresh LF and cooked LF showed no significant effect on the viability of macrophages after 24 h incubation. Fresh LF was found to be the most potent inhibitor of nitric oxide (NO) production at 100 µg/ml, while pan-fried LF showed little inhibitory effect on lipoloysaccharide (LPS) stimulated murine machrophage RAW264.7 cells. In contrast with its effect on NO production, pan-fried LF showed significant attenuation of the expression of inducible nitiric oxide synthase (iNOS) compared with fresh LF. In the cooking method of LF, PGE2 production was not affected in the LPS-induced RAW 264.7 cells. In LPS-induced RAW 264.7 cells, pretreatment by fresh and cooked LF increased COX2 mRNA expression. The 3-O-caffeoylquinic acid content of blanching and pan-frying LF increased by 4.92 and 9.7 fold with blanching and pan-frying respectively in comparison with uncooked LF. CONCLUSIONS: Regardless of the cooking method, Ligularia fischeri exhibited potent inhibition of NO production through expression of iNOS in LPS-induced RAW264.7 cells.

The Expression of Multiple Proteins as Prognostic Factors in Colorectal Cancer: Cathepsin D, p53, COX-2, Epidermal Growth Factor Receptor, C-erbB-2, and Ki-67

BACKGROUND/AIMS: A single gene mutation alone cannot explain the poor prognosis of colorectal cancer. This study aimed to establish a correlation between the expression of six proteins and the prognosis of colorectal cancer patients. METHODS: Tissue samples were collected from 266 patients who underwent surgery for colorectal cancer at our institution from January 2006 to December 2007. The expression of six proteins were determined using immunohistochemical staining of specimens. RESULTS: Cathepsin D, p53, COX-2, epidermal growth factor receptor, c-erbB-2, and Ki-67 expression were detected in 38.7%, 60.9%, 37.6%, 35.7%, 30.1%, and 74.4% of the samples, respectively. The expression of cathepsin D was significantly correlated with reduced cancer-free survival (p=0.036) and colorectal cancer-specific survival (p=0.003), but the other expression levels were not. In a multivariate analysis, cathepsin D expression was found to be an independent prognostic factor for poorer colorectal cancer-specific survival (hazard ratio, 8.55; 95% confidence interval, 1.07 to 68.49). Furthermore, patients with tumors expressing four or more of the proteins had a significantly decreased cancer-free survival rate (p=0.006) and colorectal cancer-specific survival rate (p=0.002). CONCLUSIONS: Patients with cathepsin D positivity had a poorer outcome than patients who were cathepsin D-negative. Thus, cathepsin D may provide an indicator for appropriate intensive follow-up and adjuvant chemotherapy.

Increased Expression of Cyclooxygenase-2 is Associated with the Progression to Cirrhosis

BACKGROUND/AIMS: To investigate the degree of cyclooxygenase-2 (COX-2) protein expression in chronic hepatitis and cirrhosis. METHODS: COX-2 protein expression was evaluated in 43 cases of chronic hepatitis and 24 cases of cirrhosis using immunohistochemical techniques. The COX-2 immunohistochemical staining score was assessed using the scoring systems of Pazirandeh et al and Qiu et al. and each scoring system was based on a sum of the parameters of staining intensity and distribution. RESULTS: The mean COX-2 expression scores in chronic hepatitis and cirrhosis were 2.5 +/- 1.3 vs. 3.3 +/- 1.1 (p = 0.008), and 3.2 +/- 2.0 vs. 4.5 +/- 1.7 (p = 0.006), respectively, based on the Pazirandeh et al. and Qiu et al. scoring systems. The percentage samples of high COX-2 expression score (4 to 5) in chronic hepatitis and cirrhosis were 16.3% vs. 45.8% (p = 0.022), and 23.3% vs. 50% (p = 0.021), respectively, based on the two scoring systems. The mean COX-2 expression scores based on the severity of hepatic fibrosis scored using Ishak's modified staging system (fibrosis score 0 to 3 vs. 4 to 6) were 2.4 +/- 1.3 vs. 3.2 +/- 1.1 (p = 0.009), and 3.1 +/- 2.0 vs. 4.3 +/- 1.8 (p = 0.009), respectively, based on the two scoring systems. CONCLUSIONS: COX-2 expression was significantly higher in liver cirrhosis group than in chronic hepatitis. COX-2 expression scores according to Ishak's staging was significantly higher in the advanced fibrosis group. COX-2 may play a role in the progression of hepatic fibrosis.

ERK-1/-2 and p38 Kinase Oppositely Regulate 15-deoxy-delta(12,14)-prostaglandinJ2-Induced PPAR-gamma Activation That Mediates Dedifferentiation But Not Cyclooxygenase-2 Expression in Articular Chondrocytes

Peroxisome proliferator-activated receptor gamma (PPAR-gamma) is a ligand-activated transcription factor and plays an important role in growth, differentiation, and inflammation in different tissues. In this study, we investigated the effects of 15d-PGJ2, a high-affinity ligand of PPAR-gamma, on dedifferentiation and on inflammatory responses such as COX-2 expression and PGE2 production in rabbit articular chondrocytes with a focus on ERK-1/-2, p38 kinase, and PPAR-gamma activation. We report here that 15d-PGJ2 induced dedifferentiation and/or COX-2 expression and subsequent PGE2 production. 15d-PGJ2 treatment stimulated activation of ERK-1/-2, p38 kinase, and PPAR-gamma. Inhibition of ERK-1/-2 with PD98059 recovered 15d-PGJ2-induced dedifferentiation and enhanced PPAR-gamma activation, whereas inhibition of p38 kinase with SB203580 potentiated dedifferentiation and partially blocked PPAR-gamma activation. Inhibition of ERK-1/-2 and p38 kinase abolished 15d-PGJ2-induced COX-2 expression and subsequent PGE2 production. Our findings collectively suggest that ERK-1/-2 and p38 kinase oppositely regulate 15d-PGJ2-induced dedifferentiation through a PPAR-gamma-dependent mechanism, whereas COX-2 expression and PGE2 production is regulated by ERK-1/-2 through a PPAR-gamma-independent mechanism but not p38 kinase in articular chondrocytes. Additionally, these data suggest that targeted modulation of the PPAR-gamma and mitogen-activated protein kinase pathway may offer a novel approach for therapeutic inhibition of joint tissue degradation.

Cyclooxygenase-2 and Inducible Nitric Oxide Synthase Expression in Thyroid Neoplasms and Their Clinicopathological Correlation

To evaluate the expressions of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in thyroid neoplasms in a Korean population, we studied a total of 154 cases: papillary carcinoma of classical type (PTC), 86; follicular adenoma (FA), 21; follicular carcinoma (FC), 35; medullary carcinoma (MC), 3; undifferentiated carcinoma (UC), 5; and Hurthle cell neoplasm (HN), 4. Using immunohistochemical staining, COX-2 expression was detected in 62 (72.1%) PTC specimens, 5 (23.8%) FA specimens, 10 (28.6%) FC specimens, 0 (0.0%) MC specimens, 1 (20.0%) UC specimen, and 3 (75%) HN specimens. iNOS expression was detected in 66 (76.7%) PTC specimens, 4 (19.0%) FA specimens, 13 (37.1%) FC specimens, 0 (0.0%) MC specimens, 3 (60.0%) UC specimens, and 4 (100%) HN specimens. The results showed that COX-2 and iNOS were frequently expressed in the PTC and HN specimens, and iNOS was more frequently overexpressed in the FC specimens than in the FA specimens. In PTC, COX-2 and iNOS were significantly overexpressed in patients over 45 yr of age (p=0.029, p=0.041), and iNOS expression was increased in patients with a large primary tumor (p=0.028). These results suggest that the upregulation of COX-2 and iNOS may contribute to the tumor progression of thyroid gland, particularly in PTC and HN, and iNOS may play an adjuvant role during the tumor progression of FC.

Expression of Cyclooxygenase-2, p53 and Ki-67 in Gastric Cancer

It has been reported that p53 mutation may contribute to upregulate cyclooxygenase (COX)-2 expression that is observed in malignant tissues. These molecules are involved in carcinogenesis by affecting tumor cell proliferation. The aim of this study was to examine the relationship between COX-2 or p53 expression and clinico-pathological characteristics including tumor cell proliferation in gastric cancer. COX-2 and p53 expressions were investigated with immunostaining, in tissue specimens obtained from 119 patients who underwent surgery for gastric cancer. The Ki-67 labeling index (LI) was counted by Ki-67 immunostaining. COX-2 and p53 expressions correlated significantly with depth of tumor invasion. However, there was no association between COX-2 or p53 expression and survival. p53 expression did not correlate with COX-2 expression. There was no significant difference in various clinicopathological variables between Ki-67 LI subgroups. The mean Ki-67 LI value of COX-2 positive tumors was significantly higher than that of negative tumors. The mean Ki-67 LI value of p53 positive tumors was not significantly higher than that of negative tumors. The mean Ki-67 LI value of both COX-2 and p53 positive tumors was significantly higher than that of both negative tumors. These results imply that COX-2 expression is associated with tumor cell proliferation of gastric cancer.

Cyclo-oxygenase-2 and p53 Immunoreactivity in Superficial Early Colorectal Carcinoma / 대한소화기학회지

BACKGROUND/AIMS: De novo colorectal carcinoma shows more aggressive behavior including submucosal invasiveness. Both p53 and cyclo-oxygenase-2 (COX-2) have been shown to be involved in colon carcinogenesis, progression from adenoma to carcinoma, and submucosal invasion by tumor. We performed this study to evaluate the expression of p53 and COX-2 protein in de novo carcinoma, compared with ex-adenoma carcinoma. METHODS: Twenty three flat adenomas, 19 ex-adenoma carcinomas, 6 de novo carcinomas were included in this study. The expression of p53, COX-2 and Ki-67 were examined immunohistochemically. RESULTS: Both ex- adenoma carcinomas and de novo carcinomas showed similar size and shape. Positive staining for p53 was detected in 3 of 23 (13%) flat adenomas, in 11 of 19 (57.8%) ex-adenoma carcinomas (p<0.05), and in 1 of 6 (16.6%) de novo carcinomas. Increased numbers of COX-2 positive tumor cells were observed in 1 of 23 (4.3%) flat adenomas, in 2 of 19 (10.5%) ex-adenoma carcinomas, and in 3 of 6 (50%) de novo carcinomas. COX-2 positive expression showed increased tendency in de novo carcinoma (p=0.073). There was no correlation between COX-2, p53, and Ki-67 expression. CONCLUSION: De novo carcinoma shows increased tendency of COX-2 expression, but decreased p53 expression when compared to ex-adenoma carcinoma. These immunohistochemical findings are in accordance with the fact that de novo carcinoma has no preceding adenoma, with more frequent submucosal invasion despite the small lesion size.