Cyclooxygenase-2 (COX-2) mRNA expression levels in normal lung tissues and non-small cell lung cancers

Bellidifolin Inhibits Proliferation of A549 Cells by Regulating STAT3/COX-2 Expression and Protein Activity

Objectives

Bellidifolin (BEL) is one type of tetraoxygenated xanthone that is particularly found in Swertia and Gentiana (Gentianaceae). Despite its broad range of pharmacological activities, it is still unclear whether BEL could be used for lung cancer treatment. Hence, we presently demonstrate the roles of BEL towards the proliferative inhibition of the prototypical A549 lung cancer cells.

Materials and Methods

The antiproliferative activity of BEL was initially verified by cellular experiments. A network pharmacology method was then pursued to assess BEL potential molecular targets from the platform for pharmacological analysis of Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP). Disease enrichment of potential targets and construction of compound-target-disease network maps were performed based on a total of 20 diseases. Two core targets related to the BEL-mediated effect in A549 cells were obtained by importing potential targets into a protein-protein interaction database (STRING) and also analyzing respective data of related targets into this database. Last, these core targets were examined by in vitro analysis and molecular docking.

Results

CCK8 assays indicated that treatment with 50-100 μm BEL had an inhibitory effect on the proliferation of human A549 lung cancer cells, whereas this effect was time- and concentration-dependent. As control, treatment with 50-100 μm BEL did not inhibit the proliferation of normal lung epithelial cells (BEAS-2b cell line). H&E staining of BEL-treated A549 cells showed that, upon an increase of drug concentration, nuclear condensation and fragmentation were largely observed. Cell cycle analysis showed that in vitro treatment with 75-100 μm BEL could block A549 cells in S and G2 phases. Western blot analyses showed that after 72 hours of BEL treatment, the level of caspase-8/3 in A549 cells increased, and the level of PARP1 decreased in a dose-dependent manner. Network pharmacology analysis also indicated that lung cancer was the major disease susceptible to BEL treatment. At the same time, STAT3 and COX-2 were identified as two core targets of BEL in lung cancer treatment. Functional analyses further revealed that the cytotoxicity effect of BEL in A549 cells potentially involved the STAT3/COX-2 pathway. Moreover, molecular docking analysis indicated that BEL structure properly matches with COX-2 and STAT3 in space shape, thus illustrating the putative molecular mechanism of BEL's anticancer effect.

Conclusions

Based on a series of in vitro analyses, network pharmacology, and molecular docking, the potential mechanism involving the antiproliferative and cytotoxic effects of BEL in lung cancer cells was investigated. Our study may help providing some theoretical basis for the discovery of novel phytotherapy drugs applicable for the treatment of lung cancer.

Prostaglandin E-Major Urinary Metabolite (PGE-MUM) as a Tumor Marker for Lung Adenocarcinoma

Background: Prostaglandin E2 (PGE2) is metabolized to prostaglandin E-major urinary metabolite (PGE-MUM). Enhanced cyclooxygenase-2 (COX-2) expression demonstrated in lung adenocarcinoma indicates increased PGE-MUM levels in patients with lung adenocarcinoma. Objectives: We aimed to elucidate the clinical usefulness of measuring PGE-MUM as an indicator of tumor burden in patients with lung adenocarcinoma. Methods: PGE-MUM was measured by a radioimmunoassay in control healthy volunteers (n = 124) and patients with lung adenocarcinoma (n = 54). Associations between PGE-MUM levels and clinical characteristics of the patients (including lung cancer stage and TNM factors (T: Tumor, N: Node, M: Metastasis) were examined. Results: PGE-MUM levels were significantly elevated in patients with lung adenocarcinoma. A PGE-MUM level of 14.9 μg/g∙Cr showed 70.4% sensitivity and 67.7% specificity for the diagnosis of lung adenocarcinoma. PGE-MUM levels tended to be positively correlated with cancer progression as determined by the TNM staging system. Advanced stage (stage III, stage IV, and recurrence) was significantly associated with high PGE-MUM levels by logistic regression analysis. No apparent correlation was demonstrated between PGE-MUM and carcinoma embryonic antigen (CEA) levels. Conclusions: PGE-MUM can be a promising biomarker reflecting the systemic tumor burden of lung adenocarcinoma.

Systematic review and meta-analysis of the benefit of celecoxib in treating advanced non-small-cell lung cancer

Background

The clinical benefit of a selective cyclooxygenase-2 inhibitor, celecoxib, combined with anticancer therapy in advanced non-small-cell lung cancer (NSCLC) remains unclear. A meta-analysis was performed to address the efficacy and safety of celecoxib in patients with advanced NSCLC.

Materials and methods

Three databases, including PubMed, EMBASE, and the Cochrane Library, were systematically searched for available literature until March 1, 2018. Data on tumor response rates, one-year survival, overall survival, progression-free survival, and toxicities were extracted from the included randomized clinical trials. Subgroup analysis was carried out according to the line of treatment. Review Manager 5.3 software was applied to conduct the meta-analysis.

Results

A total of 7 randomized controlled trials involving 1,559 patients with advanced NSCLC were enrolled for analysis. The pooled overall response rate (ORR) of celecoxib added to systemic therapy was not significantly improved (risk ratio [RR] =1.14, 95% CI =0.96–1.35, P=0.13). Additionally, no differences were observed between the celecoxib and placebo groups regarding 1-year survival (RR =0.99, 95% CI =0.88–1.12, P=0.91). Subgroup analysis showed that adding celecoxib to the first-line treatment significantly improved the ORR (RR =1.21, 95% CI =1.01–1.44, P=0.04) and partial response rate (RR =1.26, 95% CI =1.01–1.58, P=0.04). The aggregated Kaplan–Meier analysis found no significant difference between celecoxib and placebo regarding the 5-year overall survival (median, 12.9 vs 12.5 months, P=0.553) and 5-year progression-free survival (median, 7.4 vs 7.2 months, P=0.641). The increased RR of leukopenia (RR =1.25, 95% CI =1.03–1.50) and thrombocytopenia (RR =1.39, 95% CI =1.11–1.75) indicated that celecoxib increased hematologic toxicities (grade ≥III). However, celecoxib did not increase the related risks of thrombosis or embolism (RR =1.26, 95% CI =0.66–2.39) and cardiac ischemia (RR =1.16, 95% CI =0.39–3.44).

Conclusion

Celecoxib had no benefit on survival indices for advanced NSCLC but improved the ORR of first-line treatment. Additionally, celecoxib increased the rate of hematologic toxicities without increasing the risk of cardiovascular events.

Hepatic cyclooxygenase-2 overexpression induced spontaneous hepatocellular carcinoma formation in mice

Cyclooxygenase (COX)-2 is upregulated in hepatocellular carcinoma (HCC). However, the direct causative effect of COX-2 in spontaneous HCC formation remains unknown. We thus investigate the role and molecular pathogenesis of COX-2 in HCC by using liver-specific COX-2 transgenic (TG) mice. We found spontaneous HCC formation with elevated inflammatory infiltrates and neovessels in male TG mice (3/21, 14.3%), but not in any of male WT mice (0/19). Reduced representation bisulfite sequencing (RRBS) and gene expression microarrays were performed in the HCC tumor and non-HCC liver tissues to investigate the molecular mechanisms of COX-2-driven HCC. By RRBS, DNA promoter hypermethylation was identified in HCC from TG mice. Induction of promoter hypermethylation was associated with reduced tet methylcytosine dioxygenase 1 (TET1) expression by COX-2. TET1 could catalyze the conversion of 5-methylcytosine into 5-hydroxymethylcytosine (5hmC) and prevents DNA hypermethylation. In keeping with this, loss of 5hmC was demonstrated in COX-2-induced HCC. Consistently, COX-2 overexpression in human HCC cell lines could reduce both TET1 expression and 5hmc levels. Integrative analyses of DNA methylation and gene expression profiles further identified significantly downregulated genes including LTBP1, ADCY5 and PRKCZ by promoter methylation in COX-2-induced HCC. Reduced expression of LTBP1, ADCY5 and PRKCZ by promoter hypermethylation was further validated in human HCCs. Bio-functional investigation revealed that LTBP1 inhibited cell proliferation in HCC cell lines, suggesting its potential role as a tumor suppressor in HCC. Gene expression microarrays revealed that signaling cascades (AKT (protein kinase B), STK33 (Serine/Threonine kinase 33) and MTOR (mechanistic target of rapamycin) pathways) were enriched in COX-2-induced HCC. In conclusion, this study demonstrated for the first time that enhanced COX-2 expression in hepatocytes is sufficient to induce HCC through inducing promoter hypermethylation by reducing TET1, silencing tumor-suppressive genes and activating key oncogenic pathways. Inhibition of COX-2 represents a mechanism-based target for HCC prevention.

Phase III Randomized, Placebo-Controlled, Double-Blind Trial of Celecoxib in Addition to Standard Chemotherapy for Advanced Non-Small-Cell Lung Cancer With Cyclooxygenase-2 Overexpression: CALGB 30801 (Alliance)

Purpose Tumor overexpression of cyclooxygenase-2 (COX-2) has been associated with worse outcome in non-small-cell lung cancer (NSCLC). In Cancer and Leukemia Group B (CALGB) 30203, we found that the selective COX-2 inhibitor celecoxib in addition to chemotherapy in advanced NSCLC improved progression-free and overall survival in patients with moderate to high COX-2 expression by immunohistochemistry (IHC). CALGB 30801 (Alliance) was designed to prospectively confirm that finding. Patients and Methods Patients with NSCLC (stage IIIB with pleural effusion or stage IV according to American Joint Committee on Cancer [sixth edition] criteria) were preregistered, and biopsy specimens were analyzed for COX-2 by IHC. Patients with COX-2 expression ≥ 2, performance status of 0 to 2, and normal organ function were eligible. Chemotherapy was determined by histology: carboplatin plus pemetrexed for nonsquamous NSCLC and carboplatin plus gemcitabine for squamous histology. Patients were randomly assigned to celecoxib (400 mg twice per day; arm A) or placebo (arm B). The primary objective was to demonstrate improvement in progression-free survival in patients with COX-2 index ≥ 4 with hazard ratio of 0.645 with approximately 85% power at two-sided significance level of .05. Results The study was halted for futility after 312 of the planned 322 patients with COX-2 index ≥ 2 were randomly assigned. There were no significant differences between the groups (hazard ratio, 1.046 for COX-2 ≥ 4). Subset analyses evaluating histology, chemotherapy regimen, and incremental COX-2 expression did not demonstrate any advantage for COX-2 inhibition. Elevation of baseline urinary metabolite of prostaglandin E2, indicating activation of the COX-2 pathway, was a negative prognostic factor. Values above the third quartile may have been a predictive factor. Conclusion COX-2 expression by IHC failed to select patients who could benefit from selective COX-2 inhibition. Urinary metabolite of prostaglandin E2 may be able to identify patients who could benefit from COX-2 inhibition.

Prognostic value of cyclooxygenase-2 gene polymorphisms in advanced non-small cell lung cancer patients treated with first-line platinum-based chemotherapy

AIM

Cyclooxygenase-2 (COX-2) plays an important role in cell apoptosis, angiogenesis and tumor invasion, and over-expression of COX-2 is associated with tumor development and occurrence. The aim of this study is to investigate the association between COX-2 polymorphisms and clinical outcomes in advanced non-small cell lung cancer (NSCLC) patients treated with first-line platinum-based chemotherapy.

METHODS

A total of 190 patients with IIIB or IV NSCLC who received platinum-based chemotherapy were recruited in this study. Four functional COX-2 polymorphisms, including rs689465, rs689466, rs3218625 and rs20417, were genotyped by PCR-based restriction fragment length polymorphism methods. Kaplan-Meier methods were used to compare survival by different genotypes. Cox proportional hazard models were used to identify independently significant variables.

RESULTS

The rs689465 AA genotype was significantly associated with longer overall survival (OS) (13.0 months vs 8.8 months, P = 0.019 for log-rank test; hazard ratio [HR] 0.624; 95% confidence internal [CI] 0.418-0.931) and progression-free survival (5.3 months vs 4.0 months, P = 0.018 for log-rank test; HR 0.627; 95% CI 0.421-0.934) compared with AG or GG genotype, especially in patients with adenocarcinoma (P = 0.002), performance status of 1 (P = 0.009) and stage IV disease (P = 0.012), and treated with gemcitabine-based chemotherapy (P = 0.012). Multivariate regression analysis showed that COX-2 rs689465 polymorphism had a significantly independent prognostic value for OS (P = 0.017, HR = 1.637, 95% CI = 1.093-2.453).

CONCLUSION

Our study suggested that rs689465 polymorphism could be a prognostic biomarker for advanced NSCLC patients treated with first-line platinum-based chemotherapy.

COX-2 overexpression and -8473 T/C polymorphism in 3' UTR in non-small cell lung cancer

A new class of compounds targeting cyclooxygenase 2 (COX-2) together with other different clinically used therapeutic strategies has recently shown a promise for the chemoprevention of several solid tumors including lung cancer. The aim was to study the possible role of COX-2 -8473 T/C NP and its expression in the pathogenesis of non-small cell lung cancer. One hundred ninety non-small cell lung cancer (NSCLC) patients and 200 healthy age-, sex-, and smoking-matched controls were used for polymorphic analysis, and 48 histopathologically confirmed NSCLC patients were analyzed for COX-2 messenger RNA (mRNA) and protein expression. Our results showed that the frequencies of variant genotypes 8473 CT/CC were significantly less common in the cases (30.0%) than in the controls (36%), suggesting that the 8473 C variant allele is related with lower susceptibility in NSCLC (OR = 0.79, 95% CI 0.54-1.4). However, the frequency of COX-2 -8473 TC and CC genotypes were significantly associated with age in NSCLC (P = 0.02). Quantitative real-time expression analysis showed a significant increase in the COX-2 mRNA in tumor tissues as compared to their adjacent normal tissues [delta cycle threshold (ΔCT) = 9.25 ± 4.67 vs 5.63 ± 3.85, P = 0.0001]. Multivariate logistic regression analyses revealed that the COX-2 expression was associated significantly with age (P = 0.044). Also, an increasing trend was observed in stages I and II and in female patients compared to stages III and IV and male patients, respectively, but no statistical significance was observed. However, COX-2 mRNA expression shown no association with the -8473 C variant allele. Our findings indicate that the COX-2 T8473C polymorphism may contribute to NSCLC cancer susceptibility in the Kashmiri population, while our expression analysis revealed a significant increase of COX-2 in tumor tissues as compared to their adjacent normal tissues, suggesting that it could become an important therapeutic marker in NSCLC in the future.

The association between COX-2 polymorphisms and hematologic toxicity in patients with advanced non-small-cell lung cancer treated with platinum-based chemotherapy

Background and Objective

Overexpression of COX-2 is proved to contribute to tumor promotion and carcinogenesis through stimulating cell proliferation, inhibiting apoptosis and enhancing the invasiveness of cancer cells. Apoptosis-related molecules are potential predictive markers for survival and toxicity in platinum treatment. This study aimed at investigating the association between COX-2 polymorphisms and the occurrence of grade 3 or 4 toxicity in advanced non–small cell lung cancer patients treated with platinum-based chemotherapy.

Materials and Methods

Two hundred and twelve patients with inoperable stage IIIB-IV NSCLC received first-line chemotherapy between 2007 and 2009 were recruited in this study. Four functional COX-2 polymorphisms were genotyped by PCR-based restriction fragment length polymorphism (RFLP) methods.

Results

The incidence of grade 3 or 4 hematologic toxicity was significantly higher in G allele carriers of the COX-2 rs689466 (−1195G/A) polymorphism compared with wild-type homozygotes AA (P value = 0.008; odds ratio, 2.47; 95% confidence internal, 1.26–4.84) and the significance still existed after the Bonferroni correction. Statistically significant difference was also found in grade 3 or 4 leukopenia (P value = 0.010; OR = 2.82; 95%CI = 1.28–6.20). No other significant association was observed between genotype and toxicity in the study. The haplotype analysis showed that the haplotype AGG was associated with a reduced risk of grade 3 or 4 hematologic and leukopenia toxicity (P value = 0.009; OR = 0.59; 95%CI = 0.39–0.88 and P value = 0.025; OR = 0.61; 95%CI = 0.39–0.94, respectively) while the haplotype GGG was associated with an increased risk of grade 3 or 4 hematologic and leukopenia toxicity (P value = 0.009; OR = 1.71; 95%CI = 1.14–2.56 and P value = 0.025; OR = 1.65; 95%CI  = 1.06–2.57, respectively).

Conclusion

This investigation for the first time suggested that polymorphism in COX-2 rs689466 may be a potent bio-marker in predicting severe hematologic toxicity in NSCLC patients after platinum-based chemotherapy.

Cyclooxygenase-2 up-regulates vascular endothelial growth factor via a protein kinase C pathway in non-small cell lung cancer

Background

Vascular endothelial growth factor (VEGF) expression is up-regulated via a cyclooxygenase-2 (COX-2)-dependent mechanism in non-small cell lung cancer (NSCLC), but the specific signaling pathway involved is unclear. Our aim was to investigate the signaling pathway that links COX-2 with VEGF up-regulation in NSCLC.

Material and methods

COX-2 expression in NSCLC samples was detected immunohistochemically, and its association with VEGF, microvessel density (MVD), and other clinicopathological characteristics was determined. The effect of COX-2 treatment on the proliferation of NSCLC cells (A549, H460 and A431 cell lines) was assessed using the tetrazolium-based MTT method, and VEGF expression in tumor cells was evaluated by flow cytometry. COX-2-induced VEGF expression in tumor cells was monitored after treatment with inhibitors of protein kinase C (PKC), PKA, prostaglandin E2 (PGE₂), and an activator of PKC.

Results

COX-2 over-expression correlated with MVD (P = 0.036) and VEGF expression (P = 0.001) in NSCLC samples, and multivariate analysis demonstrated an association of VEGF with COX-2 expression (P = 0.001). Exogenously applied COX-2 stimulated the growth of NSCLCs, exhibiting EC₅₀ values of 8.95 × 10^-3, 11.20 × 10^-3, and 11.20 × 10^-3 μM in A549, H460, and A431 cells, respectively; COX-2 treatment also enhanced tumor-associated VEGF expression with similar potency. Inhibitors of PKC and PGE₂ attenuated COX-2-induced VEGF expression in NLCSCs, whereas a PKC activator exerted a potentiating effect.

Conclusion

COX-2 may contribute to VEGF expression in NSCLC. PKC and downstream signaling through prostaglandin may be involved in these COX-2 actions.

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.

Cyclooxygenase-2 gene and epithelial ovarian carcinoma risk

In this study, we aimed to investigate a possible association of the COX-2 polymorphisms (-765G→C and -1195A→G) and with the risk of developing epithelial ovarian carcinoma (EOC). COX-2 gene polymorphisms was investigated in 111 healthy women and 57 patients with EOC. Individuals who had -765 CG, -1195 AA genotype, and -765 C allele had increased risk for ovarian carcinoma (P < 0.01) and individuals with -765 GG, -1195 AG genotypes and -1195 G allele seem to be protected from ovarian carcinoma (P < 0.01). Haplotype analysis confirmed the association of COX-2 gene variants with ovarian carcinoma and revealed that the frequencies of -765C: -1195A haplotype frequencies was significantly higher in patients as compared with those of controls (P = 0.048). We state that there appears to be a modulating role for the COX-2 -1195A→G and -765G→C polymorphisms in the development of EOC. To the best of our knowledge, this is the first study to show such an association.

Cyclooxygenase-2 gene and lung carcinoma risk

In this study, we aimed to investigate a possible association of the COX-2 polymorphisms with the risk of developing lung carcinoma. COX-2 (-765G→C; -1195A→G) gene polymorphisms were performed by polymerase chain reaction (PCR) and restriction fragment length polymorphism in 118 healthy individuals and 231 patients with lung carcinoma. The present study was the first that addressed the role of the COX-2-765G→C and -1195A→G polymorphisms in lung carcinoma in Turkish population. In the present study, we found that the frequencies of GG, CC, and CG genotypes of COX-2-765G→C and AA, GG, and AG genotypes of -1195A→G in our control group were 0.22, 0.22, 0.55 and 0.59, 0.0, 0.40, respectively. These frequencies in patient group were 0.34, 0.07, 0.58 and 0.74, 0.04, 0.24, respectively. There were statistically significant differences in COX-2-765G→C (P=0.0002) and -1195A→G genotypes (P=0.007) between the controls and patients. We found that individuals carrying -765 GG genotype and -765 G allele of COX-2 or 1195 AA genotype of COX-2 and -765G: -1195A haplotype had an increased risk for the development of lung carcinoma. In contrast, individuals with -765 CC, -1195 AG genotypes and -1195 G allele of COX-2 seem to be protective from lung carcinoma. We suggest that the COX-2-765G→C and -1195A→G genotypes may be a risk factor for lung carcinoma.

Prostaglandin E2 promotes lung cancer cell migration via EP4-betaArrestin1-c-Src signalsome

Many human cancers express elevated levels of cyclooxygenase-2 (COX-2), an enzyme responsible for the biosynthesis of prostaglandins. Available clinical data establish the protective effect of COX-2 inhibition on human cancer progression. However, despite these encouraging outcomes, the appearance of unwanted side effects remains a major hurdle for the general application of COX-2 inhibitors as effective cancer drugs. Hence, a better understanding of the molecular signals downstream of COX-2 is needed for the elucidation of drug targets that may improve cancer therapy. Here, we show that the COX-2 product prostaglandin E(2) (PGE(2)) acts on cognate receptor EP4 to promote the migration of A549 lung cancer cells. Treatment with PGE(2) enhances tyrosine kinase c-Src activation, and blockade of c-Src activity represses the PGE(2)-mediated lung cancer cell migration. PGE(2) affects target cells by activating four receptors named EP1 to EP4. Use of EP subtype-selective ligand agonists suggested that EP4 mediates prostaglandin-induced A549 lung cancer cell migration, and this conclusion was confirmed using a short hairpin RNA approach to specifically knock down EP4 expression. Proximal EP4 effectors include heterotrimeric Gs and betaArrestin proteins. Knockdown of betaArrestin1 expression with shRNA significantly impaired the PGE(2)-induced c-Src activation and cell migration. Together, these results support the idea that increased expression of the COX-2 product PGE(2) in the lung tumor microenvironment may initiate a mitogenic signaling cascade composed of EP4, betaArrestin1, and c-Src which mediates cancer cell migration. Selective targeting of EP4 with a ligand antagonist may provide an efficient approach to better manage patients with advanced lung cancer.

Reactive Oxygen Species And Lung Tumorigenesis By Mutant K-ras: A Working Hypothesis

Wild-type K-ras is tumor suppressive in mouse lung, but mutant K-ras is actively oncogenic. Thus, the mutant protein must acquire new, dominant protumorigenic properties. Generation of reactive oxygen species could be one such property. The authors demonstrate increased peroxides in lung epithelial cells (E10)-transfected with mutant hK-ras(va112). An associated increase in DNA damage (comet assay) correlates with increased cyclooxygenase-2 protein. This DNA damage is completely abrogated by a specific cyclooxygenase-2 inhibitor (SC58125) or by a cell-permeable modified catalase. Literature is reviewed regarding generation of reactive oxygen and cyclooxygenase-2 induction by ras, cyclooxygenase-2 release of DNA-damaging reactive oxygen, and involvement of cyclooxygenase-2 and reactive oxygen in lung cancer

Cyclooxygenase-2 expression in chronic liver diseases and hepatocellular carcinoma: an immunohistochemical study

Hepatocarcinogenesis is a multistep process characterized by hepatocyte inflammation, regeneration, and proliferation. These changes are believed to depend on the aberrant expression of various tumor suppressor genes, oncogenes and growth factors. Several studies have shown the involvement of cyclooxygenase-2 (COX-2), the inducible isoform of the enzymes that catalyze prostaglandin synthesis in various aspects of carcinogenesis. COX-2 has been described as being overexpressed in hepatocellular carcinoma (HCC) patients. Using immunohistochemistry, we studied COX-2 expression in different chronic liver diseases (CLD) including nonalcoholic steatohepatitis (NASH), chronic hepatitis (CH), liver cirrhosis (LC), and HCC in a population referred to a tertiary center in western Sicily, an area moderately endemic for CLD. Sixteen NASH, 35 CH, 15 LC, and 21 HCC samples were analyzed. Positive signs of COX-2 were observed in the cytoplasm of hepatocytes and median values were 6 (3-9) for NASH, 7 (3-9) for CH, 6 (4-9) for LC, and 4 (0-7) for HCC. COX-2 expression was significantly lower in HCC than in NASH (P < 0.001), CH (P < 0.0001), and LC (P < 0.0001). In HCC we found a wide range of COX-2 expression: from no expression in poorly differentiated areas to a high expression in well-differentiated ones, with an inverse correlation between COX-2 and tumor grading, according to Edmonson (rho=-0.67, P < 0.0001).

IN CONCLUSION

(a) COX-2 expression was significantly lower in HCC than in the other CLD; (b) COX-2 expression inversely correlated with tumor differentiation status. These results suggest that COX-2 expression could be related to the inflammatory phenomena present in the early phases of CLD and eventually to the induction of hepatocarcinogenesis.

Role of p53 in the induction of cyclooxygenase-2 by cisplatin or paclitaxel in non-small cell lung cancer cell lines

Non-small cell lung Cancer (NSCLC) is extremely resistant to chemotherapeutic agents, such as cisplatin. High expression of the inflammatory enzyme cyclooxygenase-2 (COX-2) has been shown to inhibit chemotherapy-induced apoptosis, but little is known about COX-2 regulation upon drug treatment. Recent data indicate the tumor suppressor protein p53 as an important regulator of COX-2. Therefore, TP53 status could change tumor sensitivity to chemotherapy through induction of the anti-apoptotic protein COX-2. The main objective of this work was to analyze the effect of chemotherapy on the expression of COX-2, according to TP53 status. We report herein that lung cancer cell lines expressing wild-type p53, when exposed to cisplatin treatment, induced COX-2 (mRNA and protein), with concurrent synthesis of prostaglandins (PGE(2)). In contrast, COX-2 expression was not changed after cisplatin treatment of cells containing an inactive form of p53. Further, after silencing of wild-type p53 expressed in A549 cells by RNA interference, cisplatin was no longer able to induce COX-2 expression. Therefore, we suggest that induction of COX-2 by cisplatin in NSCLC cell lines is dependent on p53. For paclitaxel treatment, an increase in COX-2 mRNA expression was observed in H460 and A549 (wild-type p53 cell lines). Moreover, paclitaxel treatment increased COX-2 expression in ACC-LC-319 cell lines (p53 null), showing a p53-independent effect. These data may have therapeutic implications in the selection of patients and strategy for future COX-2 inhibition trials.

Eicosanoid modulation in advanced lung cancer: cyclooxygenase-2 expression is a positive predictive factor for celecoxib + chemotherapy--Cancer and Leukemia Group B Trial 30203

PURPOSE

Increased expression of eicosanoids in cancer has been associated with adverse prognosis. We performed a randomized phase II trial to test the hypothesis that inhibitors of two eicosanoid pathways (cyclooxygenase-2 [COX-2], celecoxib and 5-lipoxygenase [5-LOX], zileuton) added to chemotherapy would improve outcome in advanced non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

Patients with advanced NSCLC, a performance status of 0 to 2, and no prior therapy were eligible. All patients received carboplatin area under the curve (AUC) 5.5 mg/mL x min day 1 + gemcitabine (1,000 mg/m(2)) days 1 and 8. Patients were randomly assigned to: (a) zileuton 600 mg PO qid, (b) celecoxib 400 mg PO bid, or (c) celecoxib and zileuton at the same doses. Immunohistochemical staining for COX-2 and 5-LOX was performed without knowledge of outcomes.

RESULTS

One hundred forty patients were entered and 134 were eligible and treated. There was no survival difference between the arms. COX-2 expression was a negative prognostic marker for overall survival (OS; hazard ratio [HR] = 2.51, P = .019 for index >or= 4; HR = 4.16, P = .005 for index = 9) for patients not receiving celecoxib. Patients with increased COX-2 expression (index >or= 4), receiving celecoxib had better survival than did COX-2-expressing patients not receiving drug (HR = .342, P = .005 for OS; HR = .294, P = .002 for failure-free survival). Multivariate analysis confirmed the interaction of COX-2 and celecoxib on survival. 5-LOX expression was neither prognostic nor predictive.

CONCLUSION

This study failed to demonstrate the value of dual eicosanoid inhibition or benefit from either agent alone in addition to chemotherapy. However, a prospectively defined subset analysis suggests an advantage for celecoxib and chemotherapy for patients with moderate to high COX-2 expression.

Induction of lung lesions in Wistar rats by 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and its inhibition by aspirin and phenethyl isothiocyanate

Background

The development of effective chemopreventive agents against cigarette smoke-induced lung cancer could be greatly facilitated by suitable laboratory animal models, such as animals treated with the tobacco-specific lung carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). In the current study, we established a novel lung cancer model in Wistar rats treated with NNK. Using this model, we assessed the effects of two chemopreventive agents, aspirin and phenethyl isothiocyanate (PEITC), on tumor progression.

Methods

First, rats were treated with a single-dose of NNK by intratracheal instillation; control rats received iodized oil. The animals were then sacrificed on the indicated day after drug administration and examined for tumors in the target organs. PCNA, p63 and COX-2 expression were analyzed in the preneoplastic lung lesions. Second, rats were treated with a single-dose of NNK (25 mg/kg body weight) in the absence or presence of aspirin and/or PEITC in the daily diet. The control group received only the vehicle in the regular diet. The animals were sacrificed on day 91 after bronchial instillation of NNK. Lungs were collected and processed for histopathological and immunohistochemical assays.

Results

NNK induced preneoplastic lesions in lungs, including 33.3% alveolar hyperplasia and 55.6% alveolar atypical dysplasia. COX-2 expression increased similarly in alveolar hyperplasia and alveolar atypical dysplasia, while PCNA expression increased more significantly in the latter than the former. No p63 expression was detected in the preneoplastic lesions. In the second study, the incidences of alveolar atypical dysplasia were reduced to 10%, 10% and 0%, respectively, in the aspirin, PEITC and aspirin and PEITC groups, compared with 62.5% in the carcinogen-treated control group. COX-2 expression decreased after dietary aspirin or aspirin and PEITC treatment. PCNA expression was significantly reduced in the aspirin and PEITC group.

Conclusion

(1) A single dose of 25 mg/kg body weight NNK by intratracheal instillation is sufficient to induce preneoplastic lesions in Wistar rat lungs. (2) COX-2 takes part in NNK-induced tumorigenesis but is not involved in proliferation. (3) Aspirin and PEITC have protective effects in the early stages of tumor progression initiated by NNK.

Increase of carcinogenic risk via enhancement of cyclooxygenase-2 expression and hydroxyestradiol accumulation in human lung cells as a result of interaction between BaP and 17-beta estradiol

Animal studies demonstrated that females are more susceptible than males to benzo[a]pyrene (BaP)-induced toxicities, including lung carcinogenesis. Elevation of cyclooxygenase-2 (COX-2) expression has been shown to increase the risk of cancer development. BaP induces COX-2 expression, and an interaction between BaP and estrogen in relation to COX-2 expression is suspected. In the present study, 10 muM BaP alone only slightly increased COX-2 mRNA expression and 10 nM 17-beta estradiol (E(2)) alone slightly increased prostaglandin E2 (PGE2) secretion in human bronchial epithelial cells. However, co-treatment with BaP and E(2) potentiated COX-2 mRNA expression and significantly elevated PGE2 secretion. Utilizing specific inhibitors and reporter assays, we further investigated the potentiation mechanisms of E(2) on BaP-induced COX-2 expression. First, E(2) activated estrogen receptor to increase PGE2 secretion, which directly increased COX-2 expression. Second, E(2) potentiated BaP-induced nuclear factor-kappaB (NF-kappaB) activation, which regulates COX-2 expression. Third, although the aryl hydrocarbon receptor (AhR) did not play a role in BaP-induced COX-2 expression, the potentiation effect of E(2) itself was AhR dependent. We further demonstrated that BaP induced the production of genotoxic E(2) metabolites (2- and 4-hydroxyestradiols) via AhR-up-regulated cytochromes P450 1A1 and 1B1. These metabolites could directly activate NF-kappaB to further promote COX-2 mRNA expression in human lung epithelial cells. These findings were further supported by increased PGE2 secretion in rat lung slice cultures. Our findings that the BaP-E(2) interaction enhanced COX-2 expression and hydroxyestradiol accumulation in the media of cultivated lung cells and tissues provide the needed scientific basis for higher risk of BaP-associated lung cancer in females.

Survivin depletion preferentially reduces the survival of activated K-Ras-transformed cells

To identify cancer-specific targets, we have conducted a synthetic lethal screen using a small interfering RNA (siRNA) library targeting ∼4,000 individual genes for enhanced killing in the DLD-1 colon carcinoma cell line that expresses an activated copy of the K-Ras oncogene. We found that siRNAs targeting baculoviral inhibitor of apoptosis repeat-containing 5 (survivin) significantly reduced the survival of activated K-Ras-transformed cells compared with its normal isogenic counterpart in which the mutant K-Ras gene had been disrupted (DKS-8). In addition, survivin siRNA induced a transient G2-M arrest and marked polyploidy that was associated with increased caspase-3 activation in the activated K-Ras cells. These results indicate that tumors expressing the activated K-Ras oncogene may be particularly sensitive to inhibitors of the survivin protein. [Mol Cancer Ther 2007;6(1):269–76]

Cyclooxygenase-2 expression in hepatocellular carcinoma, cirrhosis and chronic hepatitis in the United States

Aberrant expression of cyclooxygenase-2 in hepatocellular carcinoma was described in Asia. Using immunohistochemistry, we studied the expression of cyclooxygenase-2 in hepatocellular carcinoma, chronic hepatitis, and cirrhosis in a US institution. A staining score of 0-5 representing the sum of an intensity score and a distribution score was used. The mean scores were 2.2+/-1.60 for chronic hepatitis, 4.37+/-1.15 for cirrhosis, and 4.76+/-0.54 for hepatocellular carcinoma. We found a significant difference in mean staining scores between chronic hepatitis and cirrhosis (p < 0.0001), as well as between chronic hepatitis and hepatocellular carcinoma (p < 0.0001). Fibrosis correlated with cyclooxygenase-2 staining score (r=0.65).

IN CONCLUSION

(1) Cyclooxygenase-2 expression is higher in cirrhosis and hepatocellular carcinoma when compared to chronic hepatitis. (2) Cyclooxygenase-2 expression correlates with the stage of fibrosis. (3) These results imply that in chronic hepatitis and possibly in cirrhosis, hepatocarcinogenesis may be a cyclooxygenase-2 dependent mechanism.

Potential involvement of the cyclooxygenase-2 pathway in hepatocellular carcinoma-associated angiogenesis

Angiogenesis plays a crucial role in tumor development and growth. The present study was carried out to investigate the potential involvement of the cyclooxygenase-2 (Cox-2) pathway in the regulation of angiogenesis in hepatocellular carcinoma (HCC). We inhibited Cox-2 expression in HCC cell line HuH-7 by selective Cox-2 inhibitor (SC-58635) or Cox-2 siRNA. Conditioned media (CMs) from HuH-7 cells were used in angiogenic assays in vitro and in vivo. Compared with CMs from untreated and negative siRNA treated HuH-7 cells, CMs from SC-58635 and Cox-2 siRNA treated HuH-7 dramatically suppressed the proliferation, migration, and differentiation of human umbilical vein endothelial cells (HUVECs) in vitro and neovascularization in vivo. These inhibitory effects could be partially reversed by the addition of exogenous PGE2 to CMs. Furthermore, Cox-2 inhibition by SC-58635 resulted in PGE2 reduction accompanied by the down-regulation of four PGE2 receptor (EP receptor) subtypes. Treatment with SC-58635 led to the down-expression of proangiogenic factors such as VEGF, HGF, FGF2, ANGPT1 and ANGPT2 in HCC. An approximately 78% reduction of VEGF level has been found in the CM from SC-58635 treated HuH-7. Our results suggest an involvement of Cox-2 in the control of HCC-associated angiogenesis. PGE2 as a vital angiogenic factor may act directly on endothelial cells to promote HuH-7-stimulated angiogenic process. Moreover, Cox-2/PGE2/EP/VEGF pathway possibly also contributes to tumor angiogenesis in HCC. This study provides the rationale for clinical studies of Cox-2 inhibitors on the treatment or chemoprevention of HCC.

Has Cox-2 a prognostic role in non-small-cell lung cancer? A systematic review of the literature with meta-analysis of the survival results

Cyclooxygenase-2 (COX-2) is overexpressed in lung cancer, especially in adenocarcinoma (ADC). Our aim was to determine the prognostic value of COX-2 on survival in patients with lung cancer. Studies evaluating the survival impact of COX-2 in lung cancer, published until December 2005, were selected. Data for estimation of individual hazard ratios (HR) for survival were extracted from the publications and combined in a pooled HR. Among 14 eligible papers, all dealing with non-small-cell lung cancer, 10 provided results for meta-analysis of survival data (evaluable studies). Cyclooxygenase-2 positivity was associated with reduced survival, improved survival or no statistically significant impact in six, one and seven studies, respectively. Combined HR for the 10 evaluable studies (1236 patients) was 1.39 (95% confidence intervals (CI): 0.97-1.99). In stage I lung cancer (six evaluable studies, 554 patients), it was 1.64 (95% CI: 1.21-2.24). No significant impact was shown in ADC. A slight detrimental effect on survival in patients with lung cancer is associated with COX-2 expression, but the statistical significance is not reached. This effect is statistically significant in stage I, suggesting that COX-2 expression could be useful at early stages to distinguish those with a worse prognosis.

Multifaceted roles of cyclooxygenase-2 in lung cancer

Lung cancer is the leading cause of cancer death in the United States. Although the low 5-year survival rate (under 15%) has changed minimally in the last 25 years, new agents and combinations of agents that target tumor proliferation, invasion, and survival may lead to improvement in patient outcomes. There is evidence that cyclooxygenase-2 (COX-2) is overexpressed in lung cancer and promotes tumor proliferation, invasion, angiogenesis, and resistance to apoptosis. COX-2 inhibitors have been found to inhibit tumor growth in animal models and have demonstrated responses when combined with conventional therapy in phase II clinical trials. Further understanding of the mechanisms involved in COX-2-mediated tumorigenesis and its interaction with other molecules in lung cancer may lead to improved therapeutic strategies for this disease. In addition, delineation of how COX-2-dependent genes modulate the malignant phenotype will provide novel insights in lung cancer pathogenesis.

Nutritional and botanical modulation of the inflammatory cascade--eicosanoids, cyclooxygenases, and lipoxygenases--as an adjunct in cancer therapy

Emerging on the horizon in cancer therapy is an expansion of the scope of treatment beyond cytotoxic approaches to include molecular management of cancer physiopathology. The goal in these integrative approaches, which extends beyond eradicating the affected cells, is to control the cancer phenotype. One key new approach appears to be modulation of the inflammatory cascade, as research is expanding that links cancer initiation, promotion, progression, angiogenesis, and metastasis to inflammatory events. This article presents a literature review of the emerging relationship between neoplasia and inflammatory eicosanoids (PGE2 and related prostaglandins), with a focus on how inhibition of their synthesizing oxidases, particularly cyclooxygenase (COX), offers anticancer actions in vitro and in vivo. Although a majority of this research emphasizes the pharmaceutical applications of nonsteroidal anti-inflammatory drugs and selective COX-2 inhibitors, these agents fail to address alternate pathways available for the synthesis of proinflammatory eicosanoids. Evidence is presented that suggests the inhibition of lipoxygenase and its by-products-LTB4, 5-HETE, and 12-HETE-represents an overlooked but crucial component in complementary cancer therapies. Based on the hypothesis that natural agents capable of modulating both lipoxygenase and COX may advance the efficacy of cancer therapy, an overview and discussion is presented of dietary modifications and selected nutritional and botanical agents (notably, omega-3 fatty acids, antioxidants, boswellia, bromelain, curcumin, and quercetin) that favorably influence eicosanoid production.

Overexpression of cyclooxygenase-2 in non-small cell lung cancer

Evidence is accumulating to suggest that the inducible isoenzyme of cyclooxygenase (COX)-2 is up-regulated in human cancers and epidemiological studies indicate that COX inhibitors may have a protective effect on the development of lung cancer. We used immunohistochemistry and Western blotting to investigate COX expression in lung tumour specimens and three lung cancer cell lines. Sixty-five archival lung tissue samples, including 46 squamous cell and 6 adenocarcinoma lung resections, and 13 small cell lung cancer (SCLC) biopsies were studied. Dense and intense cytoplasmic COX-2 staining was found in all 52 resections from non-small cell lung cancer (NSCLC). The staining was diffuse and much stronger than adjacent respiratory epithelium. COX-2 staining was relatively weak in the majority of the SCLC samples. The bronchial and bronchiolar epithelium in the surrounding normal lung structures showed uniform COX immunoreactivity with apical concentration of the stain. There was no increase in COX-1 staining in any tumour type. Western blot analysis of the cancer lines revealed significantly higher expression of COX-1 in CORL23 line and COX-2 in two NSCLC cell lines (MOR/P; A549) compared with the expression of COX-1 and COX-2 in cultured normal bronchial epithelial cells. Our findings demonstrated COX-2 overexpression in NSCLC.

The future of cyclooxygenase-2 inhibitors and other inhibitors of the eicosanoid signal pathway in the prevention and therapy of lung cancer

Recent advances in the understanding of the biology and molecular biology of lung cancer has provided targets for novel therapeutic and chemoprevention strategies. The eicosanoid/prostaglandin signal pathway is involved in the metabolism of membrane phospholipids to end products that are involved in apoptosis, proliferation, differentiation, and angiogenesis. Abnormalities in this pathway occur frequently in lung cancer, including the overexpression of cytoplasmic phospholipase A2, cyclooxygenase-2 (COX-2), prostaglandin E (PGE) synthase, PGE2, 5-lipoxygenase (LOX), 8-LOX, and 12-LOX. Increased levels of PGE2, 5-LOX, 8-LOX, and 12-LOX promote tumor proliferation and angiogenesis and inhibit apoptosis. On the other hand, levels of proapoptotic, antiangiogenic, and antiproliferative products are frequently decreased in lung cancer due to decreased levels of enzymes such as prostacyclin synthase. These abnormalities provide a rationale for the use of inhibitors of overexpressed enzymes or replacement of anticarcinogenic end products, and such agents have been studied in preclinical and clinical trials.

Lung cancer and cyclooxygenase-2

Lung cancer is by far the leading cause of cancer-related death. Overall survival is poor and has not improved substantially over the last half century. It is clear that new approaches are needed and these should include prevention, screening for early detection, and novel treatments based on our understanding of the molecular biology of this disease. Recently attention has been drawn to the role of the cyclooxygenase (COX) enzyme and its involvement in tumorigenesis. Investigations have documented two isoforms, COX-1 and COX-2, encoded by different genes. COX-1 is constitutively expressed in most tissues and appears to be responsible for the production of prostaglandins mediating normal physiologic functions, such as the maintenance of gastric mucosa and regulation of renal blood flow. In contrast, COX-2 is normally undetectable in most tissues, and is induced by cytokines, growth factors, oncogenes, and tumor promoters. A growing body of evidence indicates COX-2 plays a key role in lung cancer, and can serve as a potential marker of prognosis in this disease. Furthermore, the recent availability of COX-2 inhibitor medications offers a unique opportunity to interfere with the development of lung cancer and the progression of metastasis. Because COX-2 inhibitors have been demonstrated to interfere with tumorigenesis, the COX-2 enzyme may be an attractive target for therapeutic and chemoprotective strategies in lung cancer patients.

COX-2 inhibitor as a radiation enhancer: new strategies for the treatment of lung cancer

Lung cancer is one of the most common causes of cancer-related mortality throughout the world, and the incidence continues to increase. Smoking is the number one cause of lung cancer. Emerging data have implicated cyclooxygenase-2 (COX-2) and prostanoid production in the pathogenesis of lung carcinoma. In invasive lung tumors, COX-2 upregulation has been reported in up to 90% of cases. COX-2 upregulation is an early event in the development of non-small-cell lung cancer and may be integral to the development of new blood vessels and production of specific proteases that are critical to growth and spread of lung malignancies. COX-2 inhibitors are known to enhance the chemosensitivity in COX-2 overexpressing lung cancer cell lines. Recently, we have demonstrated that selective COX-2 inhibitors also enhance the effect of radiation in COX-2 overexpressed cells. Therefore, inhibitors of COX-2 in combination with chemoradiation therapy may be an alternative strategy that can be tested in clinical trials. The combination of COX-2 inhibitors and radiation suggest a complementary strategy to target angiogenesis while potentially minimizing the impact on quality of life. Currently, several groups are conducting clinical trials in cervix cancer, lung cancer, and brain tumors, using inhibitors of COX-2 in combination with chemotherapy and radiation therapy. These clinical trials will help to elucidate the role of this interesting class.

The Potential Contributions of Chronic Inflammation to Lung Carcinogenesis

A number of lines of evidence suggests that chronic inflammation contributes to the process of carcinogenesis. In this article, this theme is explored with particular emphasis on the involvement of inflammation in the development of lung cancer. A number of molecular pathways activated in chronic inflammation may contribute to lung carcinogenesis. The challenge is to conceptualize a cohesive picture of this complex biology that allows for effective pharmaceutical intervention. Initial therapeutic efforts involve strategies to block single pathways, such as with cyclooxygenase (COX) activity. However, the more that is learned about the consequences of COX activity, the more evident are the relationships of this enzyme to other classes of regulatory molecules such as the potent nuclear factor-kB. In light of this emerging picture, more global intervention strategies, such as with drug combinations, may be essential for success. Further basic study is essential to sort out possible molecular relationships and to permit elucidation of the most critical regulatory circuits. Given the complexity of these molecular interactions, well-designed clinical trials that specifically evaluate the precise effects of particular antiinflammatory drugs on lung carcinogenesis will also be critical to sort out the complexity and to validate successful approaches to arresting lung carcinogenesis.

Nimesulide inhibits proliferation via induction of apoptosis and cell cycle arrest in human gastric adenocarcinoma cell line

AIM

To evaluate the potential role of Nimesulide, a selective COX-2 inhibitor, in proliferation and apoptosis of gastric adenocarcinoma cells SGC7901.

METHODS

Cell counts and MTT assay were used to quantify the influence of Nimesulide in the proliferation of SGC7901 cells. Transmission electron microscopy and flow cytometry were used to observe the induction of Nimesulide the apoptosis of SGC7901 cells and influence in the distribution of cell cycle. The expression of P27(kip1) protein was observed by immunocytochemical staining.

RESULTS

SGC-7901 Cells treated with Nimesulide at various concentrations exhibited a profound dose- and time-dependent reduction in the proliferation rate over the 72 h test period. The highest survival rate of the cells was 78.7 %, but the lowest being 22.7 %. Nimesulide induced apoptosis of the cells in a dose-dependent and non-linear manner and increased the proportion of cells in the G(0)/G(1) phase and decreased the proportion in the S and G(2)/M phase of the cell cycle. Meanwhile, Nimesulide could up-regulate the expression of P27(kip1) protein.

CONCLUSION

The induction of apoptosis and cell cycle arrest are both anti-proliferative responses that likely contribute to the antineoplastic action of nimesulide on SGC-7901 cells. The up-regulation of P27(kip1) gene may contribute to the accumulation of these cells in the G(0)/G(1) phase following treatment with Nimesulide. Selective COX-2 inhibitor may be a new channel of the chemoprevention and chemotherapy for gastric carcinoma.

Autocrine/paracrine prostaglandin E2 production by non-small cell lung cancer cells regulates matrix metalloproteinase-2 and CD44 in cyclooxygenase-2-dependent invasion

Tumor cyclooxygenase-2 (COX-2) expression is known to be associated with enhanced tumor invasiveness. In the present study, we evaluated the importance of the COX-2 product prostaglandin E2 (PGE2) and its signaling through the EP4 receptor in mediating non-small cell lung cancer (NSCLC) invasiveness. Genetic inhibition of tumor COX-2 led to diminished matrix metalloproteinase (MMP)-2, CD44, and EP4 receptor expression and invasion. Treatment of NSCLC cells with exogenous 16,16-dimethylprostaglandin E2 significantly increased EP4 receptor, CD44, and MMP-2 expression and matrigel invasion. In contrast, anti-PGE2 decreased EP4 receptor, CD44, and MMP-2 expression in NSCLC cells. EP4 receptor signaling was found to be central to this process, because antisense oligonucleotide-mediated inhibition of tumor cell EP4 receptors significantly decreased CD44 expression. In addition, agents that increased intracellular cAMP, as is typical of EP4 receptor signaling, markedly increased CD44 expression. Moreover, MMP-2-AS treatment decreased PGE2-mediated CD44 expression, and CD44-AS treatment decreased MMP-2 expression. Thus, PGE2-mediated effects through EP4 required the parallel induction of both CD44 and MMP-2 expression because genetic inhibition of either MMP-2 or CD44 expression effectively blocked PGE2-mediated invasion in NSCLC. These findings indicate that PGE2 regulates COX-2-dependent, CD44- and MMP-2-mediated invasion in NSCLC in an autocrine/paracrine manner via EP receptor signaling. Thus, blocking PGE2 production or activity by genetic or pharmacological interventions may prove to be beneficial in chemoprevention or treatment of NSCLC.

Regular aspirin use and lung cancer risk

BACKGROUND

Although a large number of epidemiological studies have examined the role of aspirin in the chemoprevention of colon cancer and other solid tumors, there is a limited body of research focusing on the association between aspirin and lung cancer risk.

METHODS

We conducted a hospital-based case-control study to evaluate the role of regular aspirin use in lung cancer etiology. Study participants included 868 cases with primary, incident lung cancer and 935 hospital controls with non-neoplastic conditions who completed a comprehensive epidemiological questionnaire. Participants were classified as regular aspirin users if they had taken the drug at least once a week for at least one year.

RESULTS

Results indicated that lung cancer risk was significantly lower for aspirin users compared to non-users (adjusted OR = 0.57; 95% CI 0.41-0.78). Although there was no clear evidence of a dose-response relationship, we observed risk reductions associated with greater frequency of use. Similarly, prolonged duration of use and increasing tablet years (tablets per day x years of use) was associated with reduced lung cancer risk. Risk reductions were observed in both sexes, but significant dose response relationships were only seen among male participants. When the analyses were restricted to former and current smokers, participants with the lowest cigarette exposure tended to benefit most from the potential chemopreventive effect of aspirin. After stratification by histology, regular aspirin use was significantly associated with reduced risk of small cell lung cancer and non-small cell lung cancer.

CONCLUSIONS

Overall, results from this hospital-based case-control study suggest that regular aspirin use may be associated with reduced risk of lung cancer.

Plasma PGE-2 levels and altered cytokine profiles in adherent peripheral blood mononuclear cells in non-small cell lung cancer (NSCLC)

INTRODUCTION

PGE-2 is constitutively produced by many non-small cell lung cancers (NSCLC) and its immunosuppressive effects have been linked to altered immune responses in lung cancer. We asked whether elevated levels of plasma PGE-2 correlated with monocyte IL10 production in the NSCLC environment. Looking for correlation in NSCLC patient blood we assayed plasma from NSCLC patients for PGE2 and IL10; we further evaluated production of IL10 by adherent mononuclear cells from a subset of these patients looking for an altered cytokine profile.

RESULTS

Our initial in vitro experiments show that monocyte IL10 induction correlates with tumor cell PGE-2 production, confirming similar reports in the literature. Data show plasma PGE-2 levels in 38 NSCLC patients are elevated compared to normal controls. Plasma IL10 levels were not significantly elevated; however, adherent monocytes derived from NSCLC patient blood did produce significantly more IL10 in 24 hr primary culture than those from normal controls (p < 0.01). The association of elevated plasma PGE-2 and monocyte derived IL-10 was not significant.

CONCLUSIONS

Elevated plasma PGE-2 and monocyte IL10 production are associated with NSCLC. The biological significance to elevated PGE-2 levels in NSCLC are unclear. Further investigation of each as a nonspecific marker for NSCLC tumor is warranted.

Oxidation of biological systems: oxidative stress phenomena, antioxidants, redox reactions, and methods for their quantification

Reactive oxygen species (ROS) and other radicals are involved in a variety of biological phenomena, such as mutation, carcinogenesis, degenerative and other diseases, inflammation, aging, and development. ROS are well recognized for playing a dual role as deleterious and beneficial species. The objectives of this review are to describe oxidative stress phenomena, terminology, definitions, and basic chemical characteristics of the species involved; examine the biological targets susceptible to oxidation and the defense mechanisms of the organism against these reactive metabolites; and analyze methodologies, including immunohistochemical markers, used in toxicological pathology in the visualization of oxidative stress phenomena. Direct detection of ROS and other free radicals is difficult, because these molecules are short-lived and highly reactive in a nonspecific manner. Ongoing oxidative damage is, thus, generally analyzed by measurement of secondary products including derivatives of amino acids, nuclei acids, and lipid peroxidation. Attention has been focused on electrochemical methods based on voltammetry measurements for evaluating the total reducing power of biological fluids and tissues. This approach can function as a tool to assess the antioxidant-reducing profile of a biological site and follow changes in pathological situations. This review thus includes different topics essential for understanding oxidative stress phenomena and provides tools for those intending to conduct study and research in this field.

Past, present, and future of gemcitabine and carboplatin regimens in advanced non-small cell lung cancer

Several chemotherapeutic regimens have emerged in the past 5 years with the capability to improve survival and quality of life of patients with advanced non-small cell lung cancer (NSCLC). Among these treatments, the regimen of gemcitabine (Gemzar) and carboplatin (Paraplatin) has gained increasing acceptance. The combination of these two drugs was initially hampered by unacceptable platelet toxicity. However, the use of a 21-day schedule with the administration of gemcitabine on days 1 and 15 or the use of a 28-day schedule with the omission of day-15 gemcitabine has clearly been well tolerated and active. Unlike taxane based regimens, there is no need for steroid premedication, and neurotoxicity and alopecia are absent. This regimen is well tolerated and easily administered on an outpatient basis. It therefore represents an excellent "platform regimen" for the addition of new agents, particularly those associated with minimal myelotoxicity. Three-drug regimens consisting of gemcitabine/carboplatin and a taxane have been evaluated both with concurrent and sequential administration of the drugs. Trials are under way or planned for the addition of novel agents such as C225, UCN-01, PKC-alpha antisense, bexarotene, COX-2 inhibitors and other agents.

Inhibitory effect of a selective cyclooxygenase-2 inhibitor on liver metastasis of colon cancer

COX-2 overexpression is recognized in various cancers, but the role of COX-2 in the progression of cancer, including the liver metastasis of colon cancer, is not clearly understood. We examined the role of COX-2 in the mechanism of liver metastasis of colon cancer, using a highly metastasizable colon carcinoma cell line, LM-H3. A COX-2 inhibitor, JTE-522, inhibited cell proliferation and invasion of LM-H3 in vitro and clearly reduced the number of metastatic nodules on the surface of nude mouse livers in vivo. We also examined the effects of JTE-522 on the production of growth factors and MMPs through the use of ELISA and gelatin zymography, respectively. JTE-522 downregulated PDGF production by LM-H3 but had no influence on VEGF production. JTE-522 also inhibited MMP-2 secretion by LM-H3. JTE-522 downregulated PGE(2) production, but the associated changes in PGE(2) did not affect PDGF and VEGF production by LM-H3. We conclude that JTE-522 downregulated the cell proliferation and invasive potential of LM-H3 by reducing the production of PDGF and MMP-2 and hypothesize that these inhibitory effects on the production of PDGF and MMP-2 can lead to inhibition of liver metastasis of colon cancer. These data indicate that the COX-2 inhibitor JTE-522 has a high potential for use as a clinical agent for the treatment of liver metastasis of colon cancer.

Aspirin and lung cancer in women

The association between aspirin use and lung cancer risk in women was examined in a case-control study nested in the New York University Women's Health Study, a large cohort in New York. Case subjects were all the 81 incident lung cancer cases who had provided information about aspirin use at enrollment and during the 1994-1996 follow up. Ten controls per case were randomly selected from among study participants who matched a case by age, menopausal status, and dates of enrollment and follow-up. Relative to no aspirin use, the odds ratio for lung cancer (all histological sub-types combined) among subjects who reported aspirin use three or more times per week for at least 6 months was 0.66 (95% confidence interval 0.34-1.28), after adjustment for smoking and education. A stronger inverse association was observed in analyses restricted to non-small cell lung cancer (adjusted odds ratio 0.39, 95% confidence interval 0.16-0.96). These results suggest that regular aspirin use might be inversely associated with risk of lung cancer in women, particularly the non-small cell sub-type.

NS-398, a selective cyclooxygenase 2 inhibitor, inhibited cell growth and induced cell cycle arrest in human hepatocellular carcinoma cell lines

Cyclooxygenase 2 (COX-2) has been suggested to be associated with liver carcinogenesis. Several reports have shown that NSAIDs inhibit the growth of hepatocellular carcinoma cell lines. There is little evidence of how COX-2 inhibitors regulate the proliferation of hepatocellular carcinoma cells or the mechanism involved. In our study, we investigated the growth-inhibitory mechanism of a selective COX-2 inhibitor, NS-398, in 4 hepatocellular carcinoma cell lines by studying cell growth, COX-2 and proliferating cell nuclear antigen (PCNA) expression, cell cycle distribution and the evidence of apoptosis. NS-398 inhibited the growth of all 4 cell lines in a time- and dose-dependent manner and the inhibitory effects were independent of the level of COX-2 protein expression. PCNA expression was downregulated by NS-398 in a dose-independent manner. NS-398 caused cell cycle arrest in the S phase with a reduction in cell numbers and cell accumulation in the G0/G1 phase, for all 4 cell lines. No evidence of apoptosis was observed in our present study. Our findings suggest that a selective COX-2 inhibitor might serve as an effective tool for the chemoprevention and treatment of hepatocellular carcinomas. A reduction in cell number in the S phase may be an important event in cell cycle arrest caused by NS-398 in hepatocellular carcinoma cell lines.

Prognostic significance of cyclooxygenase 2 mRNA expression in non-small cell lung cancer

OBJECTIVE

To investigate cyclooxygenase-2 (COX-2) mRNA expression in curatively resected non-small cell lung cancer (NSCLC) and to determine its association with prognosis.

SUMMARY BACKGROUND DATA

Lung cancer is one of the most common malignancies in the world. Despite improvements in the diagnosis and treatment of NSCLC, the 5-year survival rate remains less than 15%. Identification of prognostic predictors based on molecular alterations could lead to additional diagnostic tools and eventually to more effective therapeutic options. Overexpression of COX-2 has been reported in several human malignancies, including lung cancer, but the prognostic importance of this overexpression has not been elucidated.

METHODS

COX-2 mRNA expression was analyzed using a quantitative real-time polymerase chain reaction (Taqman) method in surgically resected tumor specimens from 89 patients with curatively resected NSCLC.

RESULTS

COX-2 mRNA was detectable in all 89 (100%) tumor tissues. High COX-2 expression in tumors was significantly associated with inferior survival. Multivariate analysis showed that high COX-2 expression is an independent predictor of worse survival in patients with NSCLC.

CONCLUSIONS

High COX-2 mRNA expression is an important biomarker for biologically aggressive disease in NSCLC and might be helpful in identifying patients who would benefit from additional therapies for controlling their disease.

Progression and NSAID-induced apoptosis in malignant melanomas are independent of cyclooxygenase II

Cyclooxygenase-II (Cox-II) overexpression is involved in the progression of various subtypes of cancer. We investigated the significance of Cox-II in the progression of malignant melanomas (MMs). Using immunohistology we determined that Cox-II is not expressed in 70 benign and malignant melanocytic tumours. Basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs) were also analysed as controls: the BCCs were consistently Cox-II negative (n = 11), whereas the SCCs showed moderate to strong Cox-II expression in 53% (n = 17). Reverse transcription-polymerase chain reaction and Western blotting of MM cell lines and MM tissues confirmed the lack of Cox-II expression in MM. However, in vitro the Cox-inhibiting non-steroidal anti-inflammatory drug (NSAID) sulindac sulphide (SIS) was significantly more effective in inducing apoptosis than sulindac sulphone (SOS), a derivative with a negligible effect on Cox (P < 0.01). The SIS doses needed for the induction of apoptosis were not significantly different in MM cell lines versus a Cox-II-positive colon carcinoma cell line (HT29). Furthermore, add-back experiments with high doses of the prostaglandins PGE2 and PGF2beta, major Cox-II products, did not abrogate this effect. We conclude that Cox-II expression is not involved in the progression of MM, and NSAID-induced apoptosis in MM cell lines seems to follow pathways independent of Cox-II. Nevertheless, Cox-II inhibitors are still candidates for therapy, though they act via an unknown mechanism.

The role of oxidative stress in indium phosphide-induced lung carcinogenesis in rats

Indium phosphide (IP), widely used in the microelectronics industry, was tested for potential carcinogenicity. Sixty male and 60 female Fischer 344 rats were exposed by aerosol for 6 h/day, 5 days/week, for 21 weeks (0.1 or 0.3 mg/m(3); stop exposure groups) or 105 weeks (0 or 0.03 mg/m(3) groups) with interim groups (10 animals/group/sex) evaluated at 3 months. After 3-month exposure, severe pulmonary inflammation with numerous infiltrating macrophages and alveolar proteinosis appeared. After 2 years, dose-dependent high incidences of alveolar/bronchiolar adenomas and carcinomas occurred in both sexes; four cases of squamous cell carcinomas appeared in males (0.3 mg/m(3)), and a variety of non-neoplastic lung lesions, including simple and atypical hyperplasia, chronic active inflammation, and squamous cyst, occurred in both sexes. To investigate whether inflammation-related oxidative stress functioned in the pathogenesis of IP-related pulmonary lesions, we stained lungs of control and high-dose animals immunohistochemically for four markers indicative of oxidative stress: inducible nitric oxide synthase (i-NOS), cyclooxygenase-2 (COX-2), glutathione-S-transferase Pi (GST-Pi), and 8-hydroxydeoxyguanosine (8-OHdG). Paraffin-embedded samples from the 3-month and 2-year control and treated females were used. i-NOS and COX-2 were highly expressed in inflammatory foci after 3 months; at 2 years, all four markers were expressed in non-neoplastic and neoplastic lesions. Most i-NOS staining, mainly in macrophages, occurred in chronic inflammatory and atypical hyperplastic lesions. GST-Pi and 8-OHdG expression occurred in cells of carcinoma epithelium, atypical hyperplasia, and squamous cysts. These findings suggest that IP inhalation causes pulmonary inflammation associated with oxidative stress, resulting in progression to atypical hyperplasia and neoplasia.

Genomic imbalances in human lung adenocarcinomas and squamous cell carcinomas

Comparative genomic hybridization analysis was performed on 67 non-small-cell lung cancers (NSCLCs), including 32 squamous cell carcinomas (SCCs) and 35 adenocarcinomas (ACs), to identify differences in the patterns of genomic imbalance between these two histologic subtypes. Among the entire tumor set, the chromosome arms most often overrepresented were 1q, 3q, 5p, and 8q, each detected in 50-55% of cases. The most frequently underrepresented arms were 9q, 3p, 8p, and 17p. The number of imbalances was similar in SCCs and ACs (median number/case: 12 and 11, respectively). Moreover, many imbalances, such as gains of 1q, 5p, and 8q, occurred at a high frequency in both histologic subgroups. Several statistically significant differences, however, were found. The most prominent difference was gain of 3q24-qter, seen in 81% of SCCs compared with 31% of ACs (P < 0.0001), with amplification at 3q25-26 being detected in eight of 32 (25%) SCCs but in only two of 35 (6%) ACs. Gain of 20p13 and loss of 4q also were seen at a significantly higher rate in SCCs than in ACs, whereas overrepresentation of 6p was more common in ACs. Gains of 7q and 8q each were associated with higher-stage tumors and either positive nodal involvement or higher tumor grade. These data suggest that genes located in several chromosomal regions, particularly 3q25-26, may be associated with phenotypic properties that differentiate lung SCCs from ACs. Furthermore, certain imbalances, prominent among them gains of 7q and 8q, may be indicative of tumor aggressiveness in NSCLCs.

Non-small cell lung cancer cyclooxygenase-2-dependent invasion is mediated by CD44

Elevated tumor cyclooxygenase (COX-2) expression is associated with increased angiogenesis, tumor invasion, and suppression of host immunity. We have previously shown that genetic inhibition of tumor COX-2 expression reverses the immunosuppression induced by non-small cell lung cancer (NSCLC). To assess the impact of COX-2 expression in lung cancer invasiveness, NSCLC cell lines were transduced with a retroviral vector expressing the human COX-2 cDNA in the sense (COX-2-S) and antisense (COX-2-AS) orientations. COX-2-S clones expressed significantly more COX-2 protein, produced 10-fold more prostaglandin E(2), and demonstrated an enhanced invasive capacity compared with control vector-transduced or parental cells. CD44, the cell surface receptor for hyaluronate, was overexpressed in COX-2-S cells, and specific blockade of CD44 significantly decreased tumor cell invasion. In contrast, COX-2-AS clones had a very limited capacity for invasion and showed diminished expression of CD44. These findings suggest that a COX-2-mediated, CD44-dependent pathway is operative in NSCLC invasion. Because tumor COX-2 expression appears to have a multifaceted role in conferring the malignant phenotype, COX-2 may be an important target for gene or pharmacologic therapy in NSCLC.