Cyclooxygenase-2 expression during carcinogenesis in the human stomach

Serum metabolomics profiling of improved metabolic syndrome is characterized by decreased pro-inflammatory biomarkers: A longitudinal study in Chinese male adults

Metabolic syndrome (MetS) is a serious global health concern. The objective of this study is to dynamically investigate the changes of metabolic profiles and metabolites in Chinese male MetS subjects after an 18 months diet and exercise intervention. Fifty male MetS patients defined according to International Diabetes Federation 2005 guidelines were subjected to diet and exercise counseling for 18 months. Serum samples were taken at baseline, 12 months, and 18 months, respectively, for clinical evaluation and metabolomics analyses. Diet and exercise intervention for 18 months achieved significant improvements in the metabolic profiles of all participants. Nineteen subjects (38.0%) exhibited MetS remission at the end of the study. A total of 812 relative features were characterized and 61 were successfully identified. Furthermore, 17 differential metabolites were of significance at both time points (baseline-12 months, baseline-18 months) and presented nonlinear trends through time. Eight metabolites (47.1%) were predominantly converged to inflammation and oxidative stress. Pro-inflammatory biomarkers were remarkably decreased after 18 months of intervention, and prostaglandin E2, neuroprotectin D1, and taxiphyllin in combination were firstly found to demonstrate a fair discriminative power (area under curve = 0.911) to predict the improvement of MetS undergone diet and exercise intervention. The significant shift of metabolomic profiling after 18 months of lifestyle counseling provide a novel insight and reveal that earlier inflammation control may be of potential benefit in MetS management.

Linking dysbiosis to precancerous stomach through inflammation: Deeper than and beyond imaging

Upper gastrointestinal endoscopy is considered the gold standard for gastric lesions detection and surveillance, but it is still associated with a non-negligible rate of missing conditions. In the Era of Personalized Medicine, biomarkers could be the key to overcome missed lesions or to better predict recurrence, pushing the frontier of endoscopy to functional endoscopy. In the last decade, microbiota in gastric cancer has been extensively explored, with gastric carcinogenesis being associated with progressive dysbiosis. Helicobacter pylori infection has been considered the main causative agent of gastritis due to its interference in disrupting the acidic environment of the stomach through inflammatory mediators. Thus, does inflammation bridge the gap between gastric dysbiosis and the gastric carcinogenesis cascade and could the microbiota-inflammation axis-derived biomarkers be the answer to the unmet challenge of functional upper endoscopy? To address this question, in this review, the available evidence on the role of gastric dysbiosis and chronic inflammation in precancerous conditions of the stomach is summarized, particularly targeting the nuclear factor-κB (NF-κB), toll-like receptors (TLRs) and cyclooxygenase-2 (COX-2) pathways. Additionally, the potential of liquid biopsies as a non-invasive source and the clinical utility of studied biomarkers is also explored. Overall, and although most studies offer a mechanistic perspective linking a strong proinflammatory Th1 cell response associated with, but not limited to, chronic infection with Helicobacter pylori, promising data recently published highlights not only the diagnostic value of microbial biomarkers but also the potential of gastric juice as a liquid biopsy pushing forward the concept of functional endoscopy and personalized care in gastric cancer early diagnosis and surveillance.

Acetyl-11-keto-β-boswellic acid inhibits proliferation and induces apoptosis of gastric cancer cells through the phosphatase and tensin homolog /Akt/ cyclooxygenase-2 signaling pathway

BACKGROUND

Gastric cancer is one of the most common malignant tumors of the digestive system worldwide, posing a serious danger to human health. Cyclooxygenase (COX)-2 plays an important role in the carcinogenesis and progression of gastric cancer. Acetyl-11-keto-β-boswellic acid (AKBA) is a promising drug for cancer therapy, but its effects and mechanism of action on human gastric cancer remain unclear.

AIM

To evaluate whether the phosphatase and tensin homolog (PTEN)/Akt/COX-2 signaling pathway is involved in the anti-tumor effect of AKBA in gastric cancer.

METHODS

Human poorly differentiated BGC823 and moderately differentiated SGC7901 gastric cancer cells were routinely cultured in Roswell Park Memorial Institute 1640 medium supplemented with 10% fetal bovine serum and 1% penicillin/streptomycin. Gastric cancer cell proliferation was determined by methyl thiazolyl tetrazolium colorimetric assay. Apoptosis was measured by flow cytometry. Cell migration was assessed using the wound-healing assay. Expression of Bcl-2, Bax, proliferating cell nuclear antigen, PTEN, p-Akt, and COX-2 were detected by Western blot analysis. A xenograft nude mouse model of human gastric cancer was established to evaluate the anti-cancer effect of AKBA in vivo.

RESULTS

AKBA significantly inhibited the proliferation of gastric cancer cells in a dose- and time-dependent manner, inhibited migration in a time-dependent manner, and induced apoptosis in a dose-dependent manner in vitro; it also inhibited tumor growth in vivo. AKBA up-regulated the expression of PTEN and Bax, and down-regulated the expression of proliferating cell nuclear antigen, Bcl-2, p-Akt, and COX-2 in a dose-dependent manner. The PTEN inhibitor bpv (Hopic) reversed the high expression of PTEN and low expression of p-Akt and COX-2 that were induced by AKBA. The Akt inhibitor MK2206 combined with AKBA down- regulated the expression of p-Akt and COX-2, and the combined effect was better than that of AKBA alone.

CONCLUSION

AKBA inhibits the proliferation and migration and promotes the apoptosis of gastric cancer cells through the PTEN/Akt/COX-2 signaling pathway.

Myrrh induces the apoptosis and inhibits the proliferation and migration of gastric cancer cells through down-regulating cyclooxygenase-2 expression

OBJECTIVE

The present study is designed to evaluate the anti-tumor effects of myrrh on human gastric cancer both in vitro and in vivo.

METHODS

The gastric cancer cell proliferation was determined by MTT assay. Apoptosis was measured by flow cytometry and Hoechst 33342 staining. Wound healing was performed to evaluate the effects of myrrh on the migration. COX-2, PCNA, Bcl-2, and Bax expressions were detected by Western blot analysis. A xenograft nude mice model of human gastric cancer was established to evaluate the anti-cancer effect of myrrh in vivo.

RESULTS

Myrrh significantly inhibited cellular proliferation, migration, and induced apoptosis in vitro as well as inhibited tumor growth in vivo. In addition, myrrh inhibited the expression of PCNA, COX-2, and Bcl-2 as well as increased Bax expression in gastric cancer cells.

CONCLUSION

Myrrh may inhibit the proliferation and migration of gastric cancer cells, as well as induced their apoptosis by down-regulating the expression of COX-2.

Gene expression patterns of COX-1, COX-2 and iNOS in H. Pylori infected histopathological conditions

BACKGROUND

Research indicates that Helicobacter pylori can inflict severe histological damage through the modulation of host-related genes. The current study investigated the effect of H. pylori genotypes in the outcome of disease, and the expression of anti-apoptotic related genes, COX-1, COX-2, and iNOS genes in benign, pre-malignant, and malignant lesions of gastric carcinogenesis.

MATERIALS AND METHODS

Tissue samples from H. pylori positive patients were graded based on the genotype of the infected H. pylori strain. Expression of COX-1, COX-2 and iNOS was assessed using a combination of real-time PCR and immunohistochemistry.

RESULTS

Gene expression studies confirmed that COX-2 and iNOS expression was highly and selectively induced in epithelium with premalignant changes such as atrophic conditions, metaplasia and dysplasia, suggesting an important role of these genes in the sequence to gastric carcinoma of the intestinal type. Furthermore, the expression of COX-2 and iNOS was also dependent on the genotype of H. pylori and subjects with genotype-1 exhibited significantly higher expressions of COX-2 and iNOS compared to other genotypes. Comparison of the expression levels among infected and uninfected individuals demonstrated significant difference in the expression pattern of COX-2 gene whereas iNOS expression was found only in subjects infected H. pylori (p < 0.001). Immunohistochemical staining showed 1.5619 folds higher propensity of COX-2 and 3.2941 folds higher intensity of iNOS expression in subjects infected with H. pylori genotype 1.

CONCLUSION

The up-regulation of COX-2 and iNOS was associated with the genotype of the H. pylori strain and the presence of certain genotype may greatly affect early events during carcinogenesis.

A comprehensive evaluation of clinical efficacy and safety of celecoxib in combination with chemotherapy in metastatic or postoperative recurrent gastric cancer patients: A preliminary, three-center, clinical trial study

AIM

To evaluate the efficacy and safety of celecoxib combined with chemotherapy in the treatment of metastatic or postoperative recurrent gastric cancer.

METHODS

This preliminary, three-center, clinical trial study was conducted between September 2010 and December 2016. In the experimental group (n = 100), patients were treated with celecoxib combined with chemotherapy, and chemotherapy alone was used in the control group. Progression-free survival (PFS) was considered as the primary efficacy parameter. Overall survival (OS), remission rate (RR), quality of life (QOL) and drug safety were considered as the secondary efficacy parameters.

RESULTS

The PFS of the experimental group was 6 months, which was not significantly longer than that of the control group (5 months, P = .73). The average OS was not significantly different between the experimental group (12 months) and the control group (10 months, P = .59). The average OS of the COX-2 positive patients in the experimental group was 14 months and it was significantly longer than the 10-month OS in the control group (P = .01). The PFS of the COX-2 positive patients in the experimental group was 7.5 months, significantly longer than the 5-month PFS of patients in the control group (P < .001). No statistical significance was identified in the incidence of nausea, neutropenia, anorexia, peripheral neurotoxicity, diarrhea, vomiting, asthenia and thrombocytopenia. The EORTC QLQ-C30 questionnaire revealed that the overall QOL of the experimental group was significantly higher than that of the control group (P < .05). No statistical significance was found in the scores of functioning scale between the 2 groups. However, the scores of the symptom scale, especially for pain and fatigue in the experimental group was remarkably higher than that in the control group (P < .05). The overall score of EORTC QLQ-STO22 for the experimental group was considerably higher compared to that for the control group (P < .05). No statistical significance was identified in term of the domains of restrictions on feeding, dysphagia, anxiety, reflux, sense of taste, dry mouth, hair loss and body shape between the 2 groups (P > .05 for all mentioned outcomes).

CONCLUSION

Celecoxib combined with chemotherapy offers more clinical benefits for COX-2 positive advanced gastric cancer patients.

In Vitro, In Silico Elucidation of Antiurease Activity, Kinetic Mechanism and COX-2 Inhibitory Efficacy of Coagulansin A of Withania coagulans

Urease enzyme plays a crucial role in the survival of Helicobacter pylori that contributes to different diseases, including peptic ulcer (gastric and duodenal ulcers). Coagulansin A is the steroidal lactone (withanolide) found in plants of solanaceae family such Withania coagulans. The current study was carried out to examine the in vitro urease, COX-2 inhibitory activity and effect on type II collagen expression of coagulansin A. Moreover, we investigated cytotoxic effects on rabbit articular chondrocytes through MTT assay. COX-2 and type II collagen expressions were determined through a Western blot method. Molecular docking and simulation studies of urease (PDBID 4H9M) and COX-2 (PDBID 5F1A) proteins were also performed as an in silico approach. Results showed that COX-2 expression was decreased dose dependably, significantly higher expression of type II collagen was observed at higher doses. In the current study, coagulansin A was found as non-toxic, and showed notable urease inhibitory activity in non-competitive manner with IC50 23.14 μm in comparison to reference drug thiourea 17.81 μm. Significant decrease in COX-2 expression (40%) and increase in type II collagen (20%) were observed as compared to control. In silico results unveiled the strong binding affinities of coagulansin A with both of these urease and COX-2 proteins. Therefore, herein we proposed the significant antiurease potential of this compound that could be used in treating different diseases such as ulcers. Moreover, detailed in vivo studies and molecular mechanism based studies are suggested.

Cyclooxygenase-2 (COX-2) gene polymorphism in patients with differentiated thyroid carcinomas in the Turkish population

Background/aim: The most common thyroid malignancies are papillary and follicular thyroid carcinomas. They account for approximately 85%-90% of all thyroid cancers. Recent studies have reported the relevance of cyclooxygenase-2 (COX-2) gene polymorphism in human carcinogenesis. The aim of this study was to investigate the relationship between thyroid carcinoma and COX-2 gene polymorphism in the Turkish population.Materials and methods: We included a total of 96 differentiated thyroid cancer patients (mean age: 46.9 ± 10.3 years; 14 males, 82 females) and 83 healthy control subjects (mean age: 46.0 ± 10.6 years; 39 males, 44 females). The frequency of -765G>C, -8473T>C, and 1195A>G gene polymorphisms in the COX-2 promoter region was investigated in thyroid cancer patients and the control group using the high-resolution melting method. Results: COX-2-765G>C and COX-2-1195A>G gene polymorphisms were similar between thyroid cancer patients and the control group. There was a statistically significant difference between COX-2-8473T>C gene polymorphism in the thyroid cancer group and the control group (P = 0.012).Conclusion: The single nucleotide gene polymorphism COX-2-8473T>C might contribute to genetic susceptibility to differentiated thyroid cancer in the Turkish population.

Mouse models for gastric cancer: Matching models to biological questions

Gastric cancer is the third leading cause of cancer-related mortality worldwide. This is in part due to the asymptomatic nature of the disease, which often results in late-stage diagnosis, at which point there are limited treatment options. Even when treated successfully, gastric cancer patients have a high risk of tumor recurrence and acquired drug resistance. It is vital to gain a better understanding of the molecular mechanisms underlying gastric cancer pathogenesis to facilitate the design of new-targeted therapies that may improve patient survival. A number of chemically and genetically engineered mouse models of gastric cancer have provided significant insight into the contribution of genetic and environmental factors to disease onset and progression. This review outlines the strengths and limitations of current mouse models of gastric cancer and their relevance to the pre-clinical development of new therapeutics.

Resveratrol Treatment Inhibits Proliferation of and Induces Apoptosis in Human Colon Cancer Cells

Background

Resveratrol, a natural isolate from plant sources, has a long and important history in traditional Chinese medicine. In the present study we investigated the effect of resveratrol on human colon cancer cell lines.

Material/Methods

We used the Cell Counting kit-8 (CCK-8) for determination of colon cancer cell viability. Apoptosis induction was analyzed using the DeadEnd™ Colorimetric TUNEL System (Promega, Madison, WI, USA). The siRNA Transfection Reagent kit (Santa Cruz Biotechnology, Inc.) was used for the administration of COX-2 silencer RNA (siRNA) into the colon cancer cells. Primer Express^® software for Real-Time PCR ver. 3.0 (Applied Biosystems, Foster City, CA, USA) was used to prepare the primers for RT-PCR.

Results

The results revealed that exposure of colon cancer cells to resveratrol inhibited cell viability. Resveratrol exhibited a significant inhibitory effect on cell viability at 30 μM concentration after 48 h of exposure. We observed that 30-μM doses of resveratrol for 72 h led to 18, 29, and 34% reduction in the viability of HCA-17, SW480, and HT29 cells, respectively. It also significantly induced apoptosis in both of the tested carcinoma cell lines. The population of apoptotic cells in HCA-17 and SW480 cell lines after 48 h of resveratrol treatment was 59.8±4 and 67.2±4%, respectively, compared to 2.3±1% in the control cells. The colon cancer cells exposed to resveratrol showed significantly lower cyclooxygenase-2 and prostaglandin receptor expression. Treatment of colon cancer cells with the inhibitor of cyclooxygenase-2, indomethacin, and administration of silencer RNA for cyclooxygenase-2 also produced similar results.

Conclusions

These findings suggest that resveratrol treatment can be a promising strategy for the treatment of colon cancer.

Molecular alterations in gastric cancer with special reference to the early-onset subtype

Currently, gastric cancer (GC) is one of the most frequently diagnosed neoplasms, with a global burden of 723000 deaths in 2012. It is the third leading cause of cancer-related death worldwide. There are numerous possible factors that stimulate the pro-carcinogenic activity of important genes. These factors include genetic susceptibility expressed in a single-nucleotide polymorphism, various acquired mutations (chromosomal instability, microsatellite instability, somatic gene mutations, epigenetic alterations) and environmental circumstances (e.g., Helicobcter pylori infection, EBV infection, diet, and smoking). Most of the aforementioned pathways overlap, and authors agree that a clear-cut pathway for GC may not exist. Thus, the categorization of carcinogenic events is complicated. Lately, it has been claimed that research on early-onset gastric carcinoma (EOGC) and hereditary GC may contribute towards unravelling some part of the mystery of the GC molecular pattern because young patients are less exposed to environmental carcinogens and because carcinogenesis in this setting may be more dependent on genetic factors. The comparison of various aspects that differ and coexist in EOGCs and conventional GCs might enable scientists to: distinguish which features in the pathway of gastric carcinogenesis are modifiable, discover specific GC markers and identify a specific target. This review provides a summary of the data published thus far concerning the molecular characteristics of GC and highlights the outstanding features of EOGC.

Drug repositioning for gynecologic tumors: a new therapeutic strategy for cancer

The goals of drug repositioning are to find a new pharmacological effect of a drug for which human safety and pharmacokinetics are established and to expand the therapeutic range of the drug to another disease. Such drug discovery can be performed at low cost and in the short term based on the results of previous clinical trials. New drugs for gynecologic tumors may be found by drug repositioning. For example, PPAR ligands may be effective against ovarian cancer, since PPAR activation eliminates COX-2 expression, arrests the cell cycle, and induces apoptosis. Metformin, an antidiabetic drug, is effective for endometrial cancer through inhibition of the PI3K-Akt-mTOR pathway by activating LKB1-AMPK and reduction of insulin and insulin-like growth factor-1 due to AMPK activation. COX-2 inhibitors for cervical cancer may also be examples of drug repositioning. PGE2 is induced in the arachidonate cascade by COX-2. PGE2 maintains high expression of COX-2 and induces angiogenic factors including VEGF and bFGF, causing carcinogenesis. COX-2 inhibitors suppress these actions and inhibit carcinogenesis. Combination therapy using drugs found by drug repositioning and current anticancer drugs may increase efficacy and reduce adverse drug reactions. Thus, drug repositioning may become a key approach for gynecologic cancer in drug discovery.

Nimesulide inhibits the growth of human esophageal carcinoma cells by inactivating the JAK2/STAT3 pathway

Although selective COX-2 inhibitors have cancer-preventive effects and induce apoptosis, the mechanisms underlying these effects are not fully understood. This study investigated the effects of nimesulide, a selective COX-2 inhibitor, on apoptosis and on the JAK/STAT signaling pathway in Eca-109 human esophageal squamous carcinoma cells. The effects and mechanisms of nimesulide on Eca-109 cell growth were studied in culture and in nude mice with Eca-109 xenografts. Cells were cultured with or without nimesulide and/or the JAK2 inhibitor AG490. Cell proliferation was evaluated using the MTT assay, and apoptosis was investigated. COX-2 mRNA expression was measured using reverse transcription polymerase chain reaction, and protein expression was detected by Western blot analysis, immunohistochemistry, and flow cytometry. Nimesulide significantly inhibited Eca-109 cell viability in vitro in a dose- and time-dependent manner (P<0.05). Nimesulide also induced apoptosis, which was accompanied by a significant decrease in the expression of COX-2 and survivin and an increase in caspase-3 expression. Nimesulide downregulated the phosphorylation levels of JAK2 and STAT3, and JAK2 inhibition by AG490 significantly augmented both nimesulide-induced apoptosis and the downregulation of COX-2 and survivin (P<0.05). In vivo, nimesulide inhibited the growth of Eca-109 tumors and the expression of p-JAK2 and p-STAT3. Thus, nimesulide downregulates COX-2 and survivin expression and upregulates caspase-3 expression in Eca-109 cells, by inactivating the JAK2/STAT3 pathway. These effects may mediate nimesulide-induced apoptosis and growth inhibition in Eca-109 cells in vitro and in vivo.

Harmine induces apoptosis and inhibits tumor cell proliferation, migration and invasion through down-regulation of cyclooxygenase-2 expression in gastric cancer

Cyclooxygenase-2 (COX-2) plays an important role in the carcinogenesis and progression of gastric cancer. Harmine is reported as a promising drug candidate for cancer therapy; however, effects and action mechanism of harmine on the human gastric cancer cells remain unclear. This study evaluated the anti-tumor effects of harmine on human gastric cancer both in vitro and in vivo. The cell proliferation was determined using MTT colorimetric assay. Apoptosis was measured by DAPI staining and flow cytometry analysis. The wound healing and transwell invasion assays were performed to evaluate the effects of harmine on the migration and invasion of gastric cancer cells. The expression of COX-2, proliferating cell nuclear antigen (PCNA), Bcl-2, Bax and matrix metalloproteinase-2 (MMP-2) was detected by Western blot analysis. Our results showed that harmine significantly inhibited cellular proliferation, migration, invasion and induced apoptosis in vitro, as well as inhibited tumor growth in vivo. In addition, harmine significantly inhibited the expression of COX-2, PCNA, Bcl-2 and MMP-2 as well as increased Bax expression in gastric cancer cells. These results collectively indicate that harmine induces apoptosis and inhibits proliferation, migration and invasion of human gastric cancer cells, which may be mediated by down-regulation of COX-2 expression.

In vivo pharmacokinetics, biodistribution and antitumor effect of amphiphilic poly(L-amino acids) micelles loaded with a novel all-trans retinoic acid derivative

Poly(amino acid)s are well-known as biodegradable and environmentally acceptable materials. In this study, a series of poly(L-aspartic acid)-b-poly(L-phenylalanine) (PAA-PPA) compounds with different degrees of polymerization were used to prepare copolymer micelles for a poorly water-soluble drug 4-amino-2-trifluoromethyl-phenyl retinate (ATPR, a novel all-trans retinoic acid derivative) and in vivo pharmacokinetics, biodistribution and antitumor efficacy of ATPR delivered by PAA-PPA micelles were evaluated. The area under the plasma concentration time curve AUC0→∞ of ATPR-loaded PAA20PPA20 micelles was 2.23 and 1.97 times higher than that of ATPR solution and ATPR CrmEL solution, respectively; In addition, the mean residence time (MRT) was increased 1.67 and 1.97-fold, respectively and the total body clearance (CL) was reduced 2.25 and 1.98-fold, respectively. The biodistribution study indicated that most of the ATPR in the ATPR-M group was distributed in the liver and there was delayed liver aggregation compared with the ATPR solution and ATPR CrmEL solution groups. Furthermore, the antitumor efficacy of ATPR-loaded PAA20PPA20 micelles was demonstrated in in vivo antitumor models involving mice inoculated with the human gastric cancer cell line SGC-7901. At the same dose of 7mg/kg, the ATPR-loaded micelles group demonstrated a better tumor growth inhibition and induced differentiation than the groups given ATPR solution and ATPR CrmEL solution. Therefore, the ATPR-loaded PAA-PPA micelles appear to be a potentially useful drug delivery system for ATPR and suitable for the chemotherapy of gastric cancer.

Role of cyclooxygenase-2 in gastric cancer development and progression

Although the incidence of gastric cancer has been declining in recent decades, it remains a major public health issue as the second leading cause of cancer death worldwide. In China, gastric cancer is still the main cause of death in patients with malignant tumors. Most patients are diagnosed at an advanced stage and mortality is high. Cyclooxygenase-2 (COX-2) is a rate-limiting enzyme in prostanoid synthesis and plays an important role in the development and progression of gastric cancer. The expression of COX-2 in gastric cancer is upregulated and its molecular mechanisms have been investigated. Helicobacter pylori infection, tumor suppressor gene mutation and the activation of nuclear factor-kappa B may be responsible for the elevated expression of COX-2 in gastric cancer. The mechanisms of COX-2 in the development and progression of gastric cancer are probably through promoting the proliferation of gastric cancer cells, while inhibiting apoptosis, assisting angiogenesis and lymphatic metastasis, and participating in cancer invasion and immunosuppression. This review is intended to discuss, comment and summarize recent research progress on the role of COX-2 in gastric cancer development and progression, and elucidate the molecular mechanisms which might be involved in the carcinogenesis.

COX-2, TFF1, and Src define better prognosis in young patients with gastric cancer

BACKGROUND AND OBJECTIVES

Despite its dwindling occurrence, gastric cancer remains a leading cause of cancer related mortality worldwide. Molecular determinants of prognosis that impact survival are being sought out as a means to facilitate rational clinical decision-making and enhance patient management. In this study, we evaluated three molecules implicated in gastric carcinogenesis and demonstrated that the differential expression of cyclooxygenase-2 (COX-2) and the viral oncogene homolog Src proteins could explain the differences in survival observed in patients older and younger than 50 years of age.

METHODS

We evaluated 5-year survival in a cohort of 423 gastric cancer patients using chronological age as a variable. Additionally, we assessed the protein expression of three molecules (COX-2, TFF1, Src) implicated in the pathogenesis of gastric cancer using immunohistochemistry.

RESULTS

We found that patients younger than 50 years of age had a better 5-year survival rate in all tumor stages. We found that the expression of COX-2 and Src correlated significantly with survival in this group without any significant impact attributable to TFF1.

CONCLUSIONS

Our study demonstrates that young gastric cancer patients have a better prognostic outlook that could in part be explained by the differential expression of COX-2 and Src.

Induction of COX-2 expression by Helicobacter pylori is mediated by activation of epidermal growth factor receptor in gastric epithelial cells

Chronic infection of the gastric mucosa by Helicobacter pylori is associated with an increased risk of developing gastric cancer; however, the vast majority of infected individuals never develop this disease. One H. pylori virulence factor that increases gastric cancer risk is the cag pathogenicity island, which encodes a bacterial type IV secretion system. Cyclooxygenase-2 (COX-2) expression is induced by proinflammatory stimuli, leading to increased prostaglandin E₂ (PGE₂) secretion by gastric epithelial cells. COX-2 expression is increased in gastric tissue from H. pylori-infected persons. H. pylori also activates the epidermal growth factor receptor (EGFR) in gastric epithelial cells. We now demonstrate that H. pylori-induced activation of COX-2 in gastric cells is dependent upon EGFR activation, and that a functional cag type IV secretion system and direct bacterial contact are necessary for full induction of COX-2 by gastric epithelial cells. PGE₂ secretion is increased in cells infected with H. pylori, and this induction is dependent on a functional EGFR. Increased apoptosis in response to H. pylori occurs in cells treated with a COX-2 inhibitor, as well as COX-2-/- cells, indicating that COX-2 expression promotes cell survival. In vivo, COX-2 induction by H. pylori is significantly reduced in mice deficient for EGFR activation compared with wild-type mice with a fully functional receptor. Collectively, these findings indicate that aberrant activation of the EGFR-COX-2 axis may lower the threshold for carcinogenesis associated with chronic H. pylori infection.

Spontaneous clearance of Helicobacter pylori after pylorus-preserving gastrectomy for gastric cancer

Residual mucosa in the gastric stump after pylorus-preserving gastrectomy (PPG) is considered a risk factor for the development of gastric stump carcinoma (GSC). Duodenogastric reflux (DGR) and Helicobacter pylori (H. pylori) infection are suspected to contribute to the development of GSC. The aim of this study was to investigate the prevalence of H. pylori in the residual stomach after PPG for gastric cancer and to assess factors associated with the presence of H. pylori. We investigated 72 patients who had undergone PPG at least 1 year prior to the study and were confirmed to be positive for H. pylori infection on presurgical endoscopic biopsy. The extent of DGR, the prevalence of H. pylori infection based on H. pylori stool antigen (HpSA) tests and the severity of gastritis were analyzed in these post-PPG patients. None of the patients had DGR, as shown by (99m)Tc-PMT. Of the 72 post-PPG patients, 33 (46%) were positive for HpSA. The prevalence of H. pylori infection was significantly lower after surgery than before surgery. The endoscopic severity of remnant gastritis, as well as histological inflammation and activity, were higher in H. pylori-positive patients than in H. pylori-negative patients. In conclusion, some patients who undergo PPG and are negative for DGR experience spontaneous clearance of H. pylori infection.

Delivery of ursolic acid (UA) in polymeric nanoparticles effectively promotes the apoptosis of gastric cancer cells through enhanced inhibition of cyclooxygenase 2 (COX-2)

It has been demonstrated that ursolic acid (UA) could effectively induces apoptosis of cancer cells by inhibiting the expression of cyclooxygenase 2 (COX-2), which constitutively expresses in gastric cancer. However, the hydrophobicity of UA increases the difficulty in its potential clinical application, which raises the possibility for its application as a novel model drug in nanoparticle-based delivery system. UA-loaded nanoparticles (UA-NPs) were prepared by a nano-precipitation method using amphilic methoxy poly(ethylene glycol)-polycaprolactone (mPEG-PCL) block copolymers as drug carriers. UA was effectively transported into SGC7901 cells by nanoparticles and localized around the nuclei in the cytoplasms. The in vitro cytotoxicity and apoptosis test indicated that UA-NPs significantly elicited more cell death at almost equivalent dose and corresponding incubation time. Moreover, UA-NPs led to more cell apoptosis through stronger inhibition of COX-2 and activation of caspase 3. The most powerful evidence from this report is that the significant differences between the cytotoxicity of free UA and UA-NPs are closely related to the expression levels of COX-2 and caspase-3, which demonstrates the superiority of UA-NPs over free UA through penetrating cell membrane. Therefore, the study offer an effective way to improve the anticancer efficiency of UA through nano-drug delivery system.

Gastrin acting on the cholecystokinin2 receptor induces cyclooxygenase-2 expression through JAK2/STAT3/PI3K/Akt pathway in human gastric cancer cells

Gastrin, cholecystokinin2 receptor (CCK2R), and cyclooxygenase-2 (COX-2) have been implicated in the carcinogenesis and progression of gastric cancer. Our study demonstrated that antagonist or siRNA against CCK2R blocked amidated gastrin (G17)-induced activation of STAT3 and Akt in gastric cancer cell lines. G17-increased COX-2 expression and cell proliferation were effectively blocked by CCK2R antagonist and inhibitors of JAK2 and PI3K. In addition, knockdown of STAT3 expression significantly attenuated G17-induced PI3K/Akt activation, COX-2 expression, and cell proliferation. These results suggest that CCK2R-mediated COX-2 up-regulation via JAK2/STAT3/PI3K/Akt pathway is involved in the proliferative effect of G17 on human gastric cancer cells.

Downregulation of miR-101 in gastric cancer correlates with cyclooxygenase-2 overexpression and tumor growth

Cyclooxygenase-2 (COX-2) plays an important role in the carcinogenesis and progression of gastric cancer. It has been demonstrated that COX-2 overexpression depends on different cellular pathways, involving both transcriptional and post-transcriptional regulation. MicroRNAs (miRNAs) are small, noncoding RNAs that function as post-transcriptional regulators. Here, we characterize miR-101 expression and its role in the regulation of COX-2 expression, which in turn, will provide us with additional insights into the potential therapeutic benefits of exogenous miR-101 for treatment of gastric cancer. Our results showed that miR-101 levels in gastric cancer tissues were significantly lower than those in the matched normal tissue (P < 0.01). Furthermore, lower levels of miR-101 were associated with increased tumor invasion and lymph node metastasis (P < 0.05). We also found an inverse correlation between miR-101 and COX-2 expression in both gastric cancer specimens and cell lines. Significant decreases in COX-2 mRNA and COX-2 levels were observed in the pre-miR-101-infected gastric cancer cells. One possible mechanism of interaction is that miR-101 inhibited COX-2 expression by directly binding to the 3'-UTR of COX-2 mRNA. Overexpression of miR-101 in gastric cancer cell lines also inhibited cell proliferation and induced apoptosis in vitro, as well as inhibiting tumor growth in vivo. These results collectively indicate that miR-101 may function as a tumor suppressor in gastric cancer, with COX-2 as a direct target.

Cyclooxygenase-2 and gastric cancer

Gastric cancer remains a leading cause of cancer-related deaths worldwide, although its incidence has been steadily declining during recent decades. Expression of cyclooxygenase-2 (COX-2) is elevated in gastric carcinomas and in their precursor lesions. COX-2 expression associates with reduced survival in gastric cancer patients, and it has also been shown to be an independent factor of poor prognosis. Several molecular mechanisms are involved in the regulation of COX-2 expression in gastric cancer cell lines, including signal transduction pathways activated by Helicobacter pylori. In gastric tumor models in vivo the role of COX-2 seems to be predominantly to facilitate tumor promotion and growth.

Expression of cyclooxygenase-2 (COX-2) in pituitary tumours

BACKGROUND

Microvessel density in angiogenesis is regarded as a prognostic factor of tumour invasiveness, independent of cell proliferation. In recent studies of pituitary tumours, correlation between the expression of cyclooxygenase-2 (COX-2) and micro-vascularization density and microvessel surface density has been established. We studied the expression of COX-2 in different types of pituitary adenomas to determine the usefulness of COX-2 expression as a prognostic factor of tumour progression or recurrence in patients with hypophyseal tumours.

MATERIAL/METHODS

We retrospectively studied a group of 60 patients of mean age 46.7±17.6 (range, 18 to 85) years who underwent pituitary tumour surgery. Expression of COX-2, as determined by immunohistochemistry, was analyzed in relation to histopathology features of tumour, clinical symptoms, MR imaging and post-operative recurrence/progression of disease.

RESULTS

COX-2 was expressed in adenomas of 87% of patients, with a median index value of 57.5% [IQR=60.5]. Highest COX-2 expression was observed in hormonally inactive adenomas and gonadotropinomas and lowest in prolactinomas. We found no differences in COX-2 expression with respect to patient age, gender, tumour size, degree of tumour invasiveness, or whether tumours were immunopositive or immunonegative for pituitary hormones, nor have we found any relation between COX-2 expression and recurrence or progression of tumour size.

CONCLUSIONS

COX-2 does not appear to be a predictive factor for recurrence or progression of tumour size. Nevertheless, due to the observed relatively high expression of COX-2 in pituitary adenomas, further studies with COX-2 inhibitors are justified in these tumours.

Immunoexpression of cyclooxygenase-2 in primary gastric carcinomas and lymph node metastases

AIM

To evaluate immunoexpression of cyclooxygenase-2 (COX-2) in primary gastric carcinomas and respective lymph node metastases.

METHODS

Immunohistochemistry to analyze COX-2 expression was performed on tissue microarray slices obtained from 36 specimens of gastrectomy and satellite lymph nodes from patients with gastric carcinoma.

RESULTS

Immunostaining was seen in most cases, and COX-2 expression was higher in lymph node metastases than in corresponding primary gastric tumors of intestinal, diffuse and mixed carcinomas, with a statistically significant difference in the diffuse histotype (P = 0.0108).

CONCLUSION

COX-2 immunoexpression occurs frequently in primary gastric carcinomas, but higher expression of this enzyme is observed in lymph node metastases of the diffuse histotype.

1-Bromopropane up-regulates cyclooxygenase-2 expression via NF-κB and C/EBP activation in murine macrophages

1-Bromopropane (1-BP) has been used in industry as an alternative to ozone-depleting solvents. In the present study, we examined the effect of 1-BP on cyclooxygenase-2 (COX-2) gene expression and analyzed the molecular mechanism of its activity in murine RAW 264.7 macrophages. 1-BP dose-dependently increased COX-2 protein and mRNA levels, as well as COX-2 promoter-driven luciferase activity in macrophages. Additionally, exposure to 1-BP markedly enhanced the production of prostaglandin E(2) (PGE(2)), a major COX-2 metabolite, in macrophages. Transfection experiments with several human COX-2 promoter constructs revealed that 1-BP activated the transcription factors nuclear factor-κB (NF-κB) and CCAAT/enhancer-binding protein (C/EBP), but not AP-1 or the cyclic AMP response element binding protein. Furthermore, Akt and mitogen-activated protein (MAP) kinases were significantly activated by 1-BP. These results demonstrated that 1-BP induced COX-2 expression via NF-κB and C/EBP activation through the Akt/ERK and p38 MAP kinase pathways. These findings provide further insight into the signal transduction pathways involved in the inflammatory effects of 1-BP.

Expression of COX2 and p53 in Rat Esophageal Cancer Induced by Reflux of Duodenal Contents

Aim. Reflux of duodenal contents can induce mucosal injury, stimulate cell proliferation, and promote tumorigenesis. We examined the expression of COX2 and p53 in rat esophageal lesions induced by duodenal content reflux. Methods. Thirty 8-week-old male Wistar rats were exposed to duodenal content esophageal reflux. All animals underwent an esophagoduodenal anastomosis (EDA) with total gastrectomy in order to produce chronic esophagitis. Ten rats were the sham. Control. They were sacrificed at the 40th week. Their esophagi were examined for HE, COX2, p53, and proliferating cell nuclear antigen (PCNA). Results. After 40 weeks of reflux, dysplasia, squamous cell carcinoma (SCC), and adenocarcinoma (ADC) were found. PCNA labeling index was higher in dysplastic and cancer tissue than that in normal. Overexpression of COX2 was shown in ADC and SCC. Wild-type p53 accumulation was found in ADC, and not in SCC. Conclusion. Reflux of duodenal contents into the esophagus led to ADC and SCC in rats. COX2 may play an important role in esophageal cancer by duodenal content reflux. Our present results suggest an association between wild-type p53 accumulation and COX2 expression in ADC, with no such relation seen in SCC.

Inhibition of cyclooxygenase-2 causes regression of gastric adenomas in trefoil factor 1 deficient mice

Cyclooxygenase-2 (Cox-2) expression is a marker of reduced survival in gastric cancer patients, and inhibition of Cox-2 suppresses gastrointestinal carcinogenesis in experimental animal models. To investigate the role of Cox-2 in gastric carcinogenesis in vivo, we utilized trefoil factor 1 (Tff1) deficient mice, which model the neoplastic process of the stomach by developing gastric adenomas with full penetrance. These tumors express Cox-2 protein and mRNA, and we have now investigated the effects of genetic deletion of the mouse Cox-2 gene [also known as prostaglandin-endoperoxide synthase 2 (Ptgs2)] and a Cox-2 selective drug celecoxib. Our results show that genetic deletion of Cox-2 in the Tff1 deleted background resulted in reduced adenoma size and ulceration with a chronic inflammatory reaction at the site of the adenoma. To characterize the effect of Cox-2 inhibition in more detail, mice that had already developed an adenoma were fed with celecoxib for 8-14 weeks, which resulted in disruption of the adenoma that ranged from superficial erosion to deep ulcerated destruction accompanied with chronic inflammation. Importantly, mice fed with celecoxib for 16 weeks, followed by control food for 9 weeks, redeveloped a complete adenoma with no detectable inflammatory process. Finally, we determined the identity of the Cox-2 expressing cells and found them to be fibroblasts. Our results show that inhibition of Cox-2 is sufficient to reversibly disrupt gastric adenomas in mice.

Effects of cyclooxygenase-2 on human esophageal squamous cell carcinoma

AIM

To study the relationship between the cyclooxygenase (COX)-2 gene and the proliferation and apoptosis of esophageal squamous carcinoma EC109 cells.

METHODS

The techniques of RNA interference (RNAi) and cell transfection, as well as the levels of oncogenicity in nude mice, were used to study the role of COX-2 in the esophageal squamous carcinoma cell (ESCC) line EC109. Following RNAi and transfection, Western blotting analysis was used to determine the expression of the COX-2 protein. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) reduction assay was used to evaluate cell growth, and flow cytometry was used to detect cell apoptosis.

RESULTS

Western blotting analysis demonstrated that COX-2 expression was significantly reduced in EC109 cells treated with COX-2-specific short interfering RNA (siRNA) but was increased in EC109 cells transfected with COX-2. Furthermore, COX-2 siRNA treatment inhibited cell proliferation (P < 0.01) and induced apoptosis in EC109 cells, as determined by an MTT assay and by flow cytometry, respectively. In contrast, transfected COX-2 led to increased cell proliferation (P < 0.05) and decreased apoptosis in EC109 cells. In addition, combination treatment of cells with COX-2 siRNA and aspirin had a synergistic effect (P < 0.01). For experiments measuring tumorigenicity, xenograft tumors of a greater volume and weight were found in the COX-2 group compared with other groups (P < 0.05). A large dose of aspirin inhibited tumor growth in nude mice effectively (P < 0.05), and the rate of tumor suppression was 51.8% in the high-dose aspirin group.

CONCLUSION

COX-2 plays a very critical role in ESCC carcinogenesis, and COX-2 siRNA combined with aspirin has the potential to be an anticancer therapy for the treatment of ESCC.

Gastric carcinogenesis

INTRODUCTION

In most patients, gastric cancer is diagnosed in advanced stage. Curative treatment options are limited and the mortality is high. The process of gastric carcinogenesis is triggered by Helicobacter pylori-driven gastritis and is further characterized by its complexity of interaction with other risk factors. Health care systems are challenged for the improvement of prevention, early diagnosis, and effective treatments.

METHODS

An extensive literature research has been performed to elucidate the interplay between etiological factors involved in gastric carcinogenesis.

RESULTS

H. pylori is the most important carcinogen for gastric adenocarcinoma. Evidence is provided by experiments including animal studies as well as clinical observational and interventional studies in humans. Eradication has the potential to prevent gastric cancer and offers the greatest benefit if performed before premalignant changes of the gastric mucosa have occurred. Bacterial virulence factors are essential players in modulating the immune response involved in the initiation of the carcinogenesis in the stomach. Host genetic factors contribute to the regulation of the inflammatory response and in the aggravation of mucosal damage. The harmful role of environmental factors is restricted to salt intake and smoking of tobacco. The ingestion of fruit and vegetables has some protective effect.

CONCLUSION

Infection with H. pylori is the major risk factor for gastric cancer development, and thus, eradication of the Helicobacter offers a promising best option for prevention of the disease. Bacterial virulence, host genetic factors, and environmental influences are interacting in the multifactorial process of gastric carcinogenesis.

COX-2 expression in papillary thyroid carcinoma (PTC) in cytological material obtained by fine needle aspiration biopsy (FNAB)

Background

COX-2 is an enzyme isoform that catalyses the formation of prostanoids from arachidonic acid. An increased COX-2 gene expression is believed to participate in carcinogenesis. Recent studies have shown that COX-2 up-regulation is associated with the development of numerous neoplasms, including skin, colorectal, breast, lung, stomach, pancreas and liver cancers. COX-2 products stimulate endothelial cell proliferation and their overexpression has been demonstrated to be involved in the mechanism of decreased resistance to apoptosis. Suppressed angiogenesis was found in experimental animal studies as a consequence of null mutation of COX-2 gene in mice. Despite the role of COX-2 expression remains a subject of numerous studies, its participation in carcinogenesis or the thyroid cancer progression remains unclear.

Methods

Twenty three (23) patients with cytological diagnosis of PTC were evaluated. After FNAB examination, the needle was washed out with a lysis buffer and the obtained material was used for COX-2 expression estimation. Total RNA was isolated (RNeasy Micro Kit), and RT reactions were performed. β-actin was used as endogenous control. Relative COX-2 expression was assessed in real-time PCR reactions by an ABI PRISM 7500 Sequence Detection System, using the ΔΔC_T method.

Results

COX-2 gene expression was higher in patients with PTC, when compared to specimens from patients with non-toxic nodular goitre (NTG).

Conclusions

The preliminary results may indicate COX-2 role in thyroid cancer pathogenesis, however the observed variability in results among particular subjects requires additional clinical data and tumor progression analysis.

Short-term therapy with celecoxib and lansoprazole modulates Th1/ Th2 immune response in human gastric mucosa

BACKGROUND

Selective cyclooxygenase-2 (COX-2) inhibitors and proton pump inhibitors may exert immune-mediated effects in human gastric mucosa. T-cell immune response plays a role in Helicobacter pylori-induced pathogenesis. This study evaluated effects of celecoxib and lansoprazole on T-helper (Th) 1 and Th2 immune response in human gastric mucosa.

METHODS

Dyspeptic patients with or without osteoarticular pain were given one of the following 4-week therapies: celecoxib 200 mg, celecoxib 200 mg plus lansoprazole 30 mg, and lansoprazole 30 mg daily. Expression of COX-2, T-bet, and pSTAT6 and production of prostaglandin E₂ (PGE₂), interferon (IFN)-γ, and interleukin (IL)-4 were determined in gastric biopsies before and after therapy. Histology was evaluated.

RESULTS

Cyclooxygenase-2 expression and PGE₂ production was higher, and Th1 signaling pathway was predominant in H. pylori-infected vs. uninfected patients. T-bet expression and IFN-γ production increased, while STAT6 activation and IL-4 production decreased following therapy with celecoxib and celecoxib plus lansoprazole, respectively. Th1 and Th2 signaling pathways down-regulated after therapy with lansoprazole, and this was associated with an improvement of gastritis. Effect of therapy was not affected by H. pylori status.

CONCLUSION

Celecoxib and lansoprazole modulate Th1/Th2 immune response in human gastric mucosa. The use of these drugs may interfere with long-term course of gastritis.

Cyclooxygenase-2 expression and its association with thyroid lesions

Cyclooxygenase (COX), also known as prostaglandin H synthase, catalyses the formation of prostaglandins from arachidonic acid. It can be expressed in response to various stimuli, such as hormones, mitogens, cytokines, other inflammatory mediators and growth factors. The product of COX-2 activity has been implicated in carcinogenesis by promoting angiogenesis, inhibiting apoptosis, increasing cell invasion and stimulating cell proliferation. It has also been proved that the regular intake of non-steroidal anti-inflammatory drugs (NSAIDs) decreases the risk of developing colon and breast cancers. Thus, it speaks for an important role of COX-2 in growth processes of various types of neoplasms. The connection between COX-2 activity and carcinogenesis has also been examined in human thyroid neoplasms. COX-2 overexpression has been reported in thyroid cancers and also in inflammatory conditions. In consequence there is significant interest whether COX-2 could be of importance as a molecular marker of malignancy in the case of thyroid carcinoma.

Anti-cancer activity of anti-p185HER-2 ricin A chain immunotoxin on gastric cancer cells

BACKGROUND AND AIM

Overexpression of the human epidermal growth factor receptor 2 (HER-2) protein has been detected in gastric cancer and has been associated with an unfavorable prognosis. We investigated the anti-cancer effects of anti-p185(HER-2) ricin A chain (RTA) immunotoxin, alone or in combination with 5-flurouracil on SGC7901-HER-2+ cells.

METHODS

SGC7901-HER-2+ cells were obtained by transfecting SGC7901 cells with HER-2-pcDNA3.1. Anti-p185(HER-2)-RTA was prepared by chemical conjugation of anti-HER-2 monoclonal antibody (mAb) and RTA. The SGC7901-HER-2+ cells were incubated with RTA, anti-p185(HER-2)-RTA, and/or 5-flurouracil. The effects of drugs on cells were evaluated by MTT assay and Annexin V-fluorescein isothiocyanate and propidium iodide double staining flow cytometry. The expression of caspase-3, caspase-9, cyclooxygenase-2, and nuclear factor-kappaB/p65 were assayed by western blot. SGC7901-HER-2+ cells were transplanted into BALB/c nude mice to produce solid tumors in an attempt to study the immunotoxin activity in vivo.

RESULTS

In vitro, anti-p185(HER-2)-RTA inhibited cell growth and induced apoptosis in SGC7901-HER-2+ cells. Anti-p185(HER-2)-RTA enhanced caspase-3 and caspase-9 activity, while downregulating the expression of cyclooxygenase-2 and nuclear factor-kappaB/p65. Its combination with 5-flurouracil further inhibited the growth of SGC7901-HER-2+ cells. In vivo, our data showed that anti-p185(HER-2)-RTA significantly inhibited the growth of SGC7901-HER-2+ cells-transplanted tumors.

CONCLUSIONS

Anti-p185(HER-2)-RTA inhibits the growth of SGC7901-HER-2+ cells. The effect may be related to the activation of caspase-3 and caspase-9 and inhibition of cyclooxygenase-2 and nuclear factor-kappaB/p65. Anti-p185(HER-2)-RTA plus 5-FU enhance anti-cancer activity, suggesting useful clues for further study for the treatment of HER-2 positive gastric cancers.

Role of innate immunity in Helicobacter pylori-induced gastric malignancy

Helicobacter pylori colonizes the majority of persons worldwide, and the ensuing gastric inflammatory response is the strongest singular risk factor for peptic ulceration and gastric cancer. However, only a fraction of colonized individuals ever develop clinically significant outcomes. Disease risk is combinatorial and can be modified by bacterial factors, host responses, and/or specific interactions between host and microbe. Several H. pylori constituents that are required for colonization or virulence have been identified, and their ability to manipulate the host innate immune response will be the focus of this review. Identification of bacterial and host mediators that augment disease risk has profound ramifications for both biomedical researchers and clinicians as such findings will not only provide mechanistic insights into inflammatory carcinogenesis but may also serve to identify high-risk populations of H. pylori-infected individuals who can then be targeted for therapeutic intervention.

Molecular targets of [6]-gingerol: Its potential roles in cancer chemoprevention

A wide variety of phenolic compounds derived from spices possess potent antioxidant, anti-inflammatory, antimutagenic, and anticarcinogenic activities. [6]-gingerol (1-[4'-hydroxy-3'-methoxyphenyl]-5-hydroxy-3-decanone) is the major pungent principle of ginger, with numerous pharmacological properties including antioxidant, anti-inflammation, and antitumor promoting properties. It could decrease inducible nitric oxide synthase (iNOS) and tumor necrosis factor alpha (TNF-alpha) expression through suppression of I-kappaB alpha (IkappaBalpha) phosphorylation, nuclear factor kappa B (NF-kappaB) nuclear translocation. Other antiproliferative mechanisms of [6]-gingerol include the release of Cytochrome c, Caspases activation, and increase in apoptotic protease-activating factor-1 (Apaf-1) as mechanism of apoptosis induction. Taken together, the chemopreventive potentials of [6]-gingerol present a promising future alternative to therapeutic agents that are expensive, toxic, and might even be carcinogenic.

COX-2 is associated with proliferation and apoptosis markers and serves as an independent prognostic factor in gastric cancer

Cyclooxygenase-2 (COX-2) is an important factor in gastric carcinogenesis, and COX-2 expression in gastric cancer patients correlates with prognosis. We have now studied the impact of COX-2 in comparison to six other tissue tumor markers, DNA index, and S-phase fraction (SPF) in a large series of gastric cancer specimens. From 342 consecutive patients, 337 archival tissue specimens were available for immunohistochemistry of COX-2, HuR, cyclin A, MMP-2, p53, p21, and Ki-67 and 313 for analysis of DNA index and S-phase fraction by flow cytometry. Associations between factors were assessed by chi-square test and survival analysis by the Kaplan-Meier method and Cox model. A significant association emerged between of COX-2 and p53 (p < 0.0001), Ki-67 (p = 0.013), DNA ploidy (p < 0.0001), and SPF (p < 0.0001). In an extended multivariate analysis, COX-2 and p53 expression were independent prognostic factors for poor survival, in addition to high stage and non-curative surgery. In gastric cancer, COX-2 expression associated with markers for apoptosis and proliferation, and furthermore, it was confirmed that COX-2 and p53 are strong prognostic indicators.

Expression of p-Akt and COX-2 in Gastric Adenocarcinomas and Adenovirus Mediated Akt1 and COX-2 ShRNA Suppresses SGC-7901 Gastric Adenocarcinoma and U251 Glioma Cell Growth In Vitro and In Vivo

Cyclooxygenase-2 (COX-2) and Protein kinase B (PKB/Akt) play a crucial role in the formation of many malignant tumors and have been shown to be the important therapeutic targets. In the present study, we examined immunohistochemical expression of phosphorylated Akt (p-Akt) and COX-2 in 45 gastric adenocarcinomas with different tumor grades. Then, adenovirus-mediated small hairpin RNA (shRNA) expression vectors rAd5-Akt1+COX-2 (rAd5-A+C) that target sequences of human COX-2 and Akt1 were used to examine the inhibitory effects on cell proliferation, invasion and apoptosis in SGC7901 gastric adenocarcinoma and U251 glioma cells. Cell growth was inhibited by over 70%, as indicated by a MTT assay, and was accompanied by G1/G0 phase arrest in the rAd5-A+C treated group, indicating poor cell growth activities. The number of cells invading through the matrigel in the rAd5-A+C treated group was significantly decreased (36.2±3.1) compared with that of the control group SGC7901 (105.0±4.0) and the nonsense sequence group rAd5-HK (102.5±6.4). In addition, the tumor volumes in the SGC7901 subcutaneous nude mouse model treated with rAd5-A+C was significantly smaller than those of the control group and nonsense sequence group rAd5-HK. When COX-2 and Akt1 were dramatically downregulated, Ki-67, CyclinD1, MMP-2, MMP-9 and Bcl-2 were also downregulated. Our results demonstrated that p-Akt and COX-2 were overexpressed in gastric adenocarcinomas and their expression levels were elevated with the ascending order of tumor malignancy; rAd5-A+C targeting COX-2 and Akt1 down-regulated their expression significantly in a sequence-specific manner, exerting inhibitory effects on SGC7901 and U251 cell proliferation, invasion and apoptosis. In conclusion, our data suggest a novel mechanism for the regulation of malignant tumor cell growth and provide evidence for combined gene therapy for malignant tumors.

Nature meets nurture: molecular genetics of gastric cancer

The immensity of genes and molecules implicated in gastric carcinogenesis is overwhelming and the relevant importance of some of these molecules is too often unclear. This review serves to bring us up-to-date with the latest findings as well as to look at the larger picture in terms of how to tackle the problem of solving this multi-piece puzzle. In this review, the environmental nurturing of intestinal cancer is discussed, beginning with epidemiology (known causative factors for inducing molecular change), an update of H. pylori research, including the role of inflammation and stem cells in premalignant lesions. The role of E-cadherin in the nature (genotype) of diffuse gastric cancer is highlighted, and finally the ever growing discipline of SNP analysis (including IL1B) is discussed.

Expression of cyclooxygenase-2 and matrix metalloproteinase-9 in human esophageal squamous cell carcinoma and its correlation with angiogenesis

AIM: To investigate the expression of COX-2 and MMP-9 in human esophageal squamous cell carcinoma and explore its correlation with angiogenesis.

METHODS: Ninety tumor specimens from patients with esophageal squamous cell carcinoma were obtained, and 34 corresponding paracancerous normal tissues were randomly selected as controls. Immunohistochemical staining was used for detecting the expression of COX-2 and MMP-9. Monoclonal antibody against CD34 was used for displaying vascular endothelial cells, and microvascular density (MVD) was determined by counting of CD34-positive vascular endothelial cells.

RESULTS: The positive expression rates of COX-2 and MMP-9 and MVD in esophageal squamous cell carcinoma were significantly higher than those in the normal esophageal mucosa (84.8% vs 20.6%, 82.2% vs 14.7% and 29.70 ± 3.82 vs 15.10 ± 2.38, respectively; all P < 0.01).The expression of COX-2 was closely related to UICC-AJCC TMN stage, cellular differentiation and lymph node metastasis (all P < 0.01), while the expression of MMP-9 and MVD was closely related to UICC-AJCC TMN stage and lymph node metastasis (both P < 0.01). COX-2 expression was positively correlated to MVD (r = 0.607, P < 0.01) and MMP-9 expression (r = 0.740, P < 0.01), while MMP-9 expression was also positively correlated to MVD (r = 0.718, P < 0.01).

CONCLUSION: Both COX-2 and MMP-9 play an important role in the angiogenesis of esophageal squamous cell carcinoma. The expression of COX-2 and MMP-9 and tumor neovascularization are closely related to tumor invasion and lymph node metastasis.

Nature meets nurture: molecular genetics of gastric cancer

The immensity of genes and molecules implicated in gastric carcinogenesis is overwhelming and the relevant importance of some of these molecules is too often unclear. This review serves to bring us up-to-date with the latest findings as well as to look at the larger picture in terms of how to tackle the problem of solving this multi-piece puzzle. In this review, the environmental nurturing of intestinal cancer is discussed, beginning with epidemiology (known causative factors for inducing molecular change), an update of H. pylori research, including the role of inflammation and stem cells in premalignant lesions. The role of E-cadherin in the nature (genotype) of diffuse gastric cancer is highlighted, and finally the ever growing discipline of SNP analysis (including IL1B) is discussed.

Molecular aspects in the diagnosis of gastric cancer

BACKGROUND

Gastric cancer (GC) represents the second most common cause of cancer-related death worldwide. The prognosis remains poor, with limited treatment options. A better understanding of the initiation and progression of GC would enable the development of general screening strategies and individualized treatment modalities.

OBJECTIVE

The assessment of tools and molecular markers for the early detection and diagnosis of GC.

METHODS

Human clinical studies published within the past 5 years are reviewed. Also, significant previous data on markers in clinical use or on relevant animal or cell culture experiments are considered.

RESULTS/CONCLUSION

Serum-based screening strategies are not ready for routine application but represent an opportunity for the identification of individuals at high risk with the need for primary gastroscopy and further surveillance, which would ultimately improve survival and prognosis of GC. Infection with Helicobacter pylori represents the principal risk factor for gastric carcinogenesis. Bacterial virulence and host genetic factors contribute to individual susceptibility. Key molecular alterations in gastric carcinogenesis are related to intra- and extracellular cascades that regulate cell proliferation, tumor invasion and metastastic spread. For the development of effective prevention and treatment modalities, it is essential to unravel the basic mechanisms of gastric carcinogenesis.

Anti-Helicobacter pylori therapy followed by celecoxib on progression of gastric precancerous lesions

AIM: To evaluate whether celecoxib, a selective cyclooxygenase 2 (COX-2) inhibitor, could reduce the severity of gastric precancerous lesions following Helicobacter pylori (H pylori) eradication.

METHODS: H pylori-eradicated patients with gastric precancerous lesions randomly received either celecoxib (n = 30) or placebo (n = 30) for up to 3 mo. COX-2 expression and activity was determined by immunostaining and prostaglandin E₂ (PGE₂) assay, cell proliferation by Ki-67 immunostaining, apoptosis by TUNEL staining and angiogenesis by microvascular density (MVD) assay using CD31 staining.

RESULTS: COX-2 protein expression was significantly increased in gastric precancerous lesions (atrophy, intestinal metaplasia and dysplasia, respectively) compared with chronic gastritis, and was concomitant with an increase in cell proliferation and angiogenesis. A significant improvement in precancerous lesions was observed in patients who received celecoxib compared with those who received placebo (P < 0.001). Of these three changes, 84.6% of sites with dysplasia regressed in patients treated with celecoxib (P = 0.002) compared with 60% in the placebo group, suggesting that celecoxib was effective on the regression of dysplasia. COX-2 protein expression (P < 0.001) and COX-2 activity (P < 0.001) in the gastric tissues were consistently lower in celecoxib-treated patients compared with the placebo-treated subjects. Moreover, it was also shown that celecoxib suppressed cell proliferation (P < 0.01), induced cell apoptosis (P < 0.01) and inhibited angiogenesis with decreased MVD (P < 0.001). However, all of these effects were not seen in placebo-treated subjects. Furthermore, COX-2 inhibition resulted in the up-regulation of PPARγ expression, a protective molecule with anti-neoplastic effects.

CONCLUSION: H pylori eradication therapy followed by celecoxib treatment improves gastric precancerous lesions by inhibiting COX-2 activity, inducing apoptosis, and suppressing cell proliferation and angiogenesis.

Epithelial metaplasia: adult stem cell reprogramming and (pre)neoplastic transformation mediated by inflammation?

Throughout adult life, new developmental commitment of adult stem cells causes metaplastic conversions to occur frequently in some organs. These reversible epithelial replacements are almost always observed in association with chronic inflammation and persistent irritation. Although metaplasia is not synonymous with dysplasia, clinical surveillance has demonstrated that these adaptive processes have an increased susceptibility to evolve into cancer. We propose that cytokines and other soluble factors released by both epithelial and inflammatory cells might alter the transcription-factor expression profile of stem cells and lead to the development of metaplasia. Furthermore, inflammatory mediators might also promote the malignant transformation of epithelial metaplasia by inducing genetic and epigenetic changes and by preventing the immune system from mounting an efficient anti-tumour immune response. A better understanding of the molecular mechanisms leading to metaplasia might help in the design of new therapies for neoplastic and degenerative diseases.

Cyclooxygenase-2 is an independent prognostic factor in gastric carcinoma patients receiving adjuvant chemotherapy and is not associated with EBV infection

PURPOSE

Cyclooxygenase-2 (COX-2) is believed to be involved in carcinogenesis in patients with chronic gastritis with Helicobacter pylori infection. EBV is detected in approximately 10% of gastric carcinomas and H. pylori induces EBV reactivation in the gastric epithelium. We aimed to evaluate significance of COX-2 in gastric carcinoma occurred in EBV and H. pylori prevalent area.

EXPERIMENTAL DESIGN

Tissue microarray samples from 457 gastric carcinoma patients who underwent gastrectomy and adjuvant chemotherapy were studied with EBER1 in situ hybridization for EBV and immunohistochemistry for COX-2 and other gastric carcinoma-related proteins (hMLH1, E-cadherin, c-erbB, and cyclin D1).

RESULTS

EBV infection was observed in 10.9% of gastric carcinomas and was associated with proximal tumor location, increased numbers of lymph node, and E-cadherin expression (P < 0.01). COX-2 overexpression was closely associated with intestinal histologic type and lower tumor stage (P = 0.01). Univariate analysis showed that pT, pN, lymph node ratio, American Joint Committee on Cancer stage, numbers of negative lymph nodes, and resection margin <1 cm were significant prognostic factors. The Cox proportional hazards regression analysis indicated that lack of COX-2 expression and resection margin <1 cm were independent prognostic factors for disease-free survival (P = 0.008 and 0.03, respectively) and overall survival (P = 0.01 and 0.007, respectively).

CONCLUSIONS

EBV infection is not associated with COX-2 expression or survival in gastric carcinoma. Lack of COX-2 expression is an independent prognostic factor in both overall and disease-free survival in gastric carcinoma. Our results indicate that COX-2 may play a role in the progression of gastric carcinoma regardless of EBV infection and is closely associated with histologic differentiation and prognosis.