Expression of cyclooxygenase-2 in human transitional cell carcinoma of the urinary bladder

Discovery of a Redox-Activatable Chemical Probe for Detection of Cyclooxygenase-2 in Cells and Animals

Cyclooxygenase-2 (COX-2) expression is up-regulated in inflammatory tissues and many premalignant and malignant tumors. Assessment of COX-2 protein in vivo, therefore, promises to be a powerful strategy to distinguish pathologic cells from normal cells in a complex disease setting. Herein, we report the first redox-activatable COX-2 probe, fluorocoxib Q (FQ), for in vivo molecular imaging of pathogenesis. FQ inhibits COX-2 selectively in purified enzyme and cell-based assays. FQ exhibits extremely low fluorescence and displays time- and concentration-dependent fluorescence enhancement upon exposure to a redox environment. FQ enters the cells freely and binds to the COX-2 enzyme. FQ exhibits high circulation half-life and metabolic stability sufficient for target site accumulation and demonstrates COX-2-targeted uptake and retention in cancer cells and pathologic tissues. Once taken up, it undergoes redox-mediated transformation into a fluorescent compound fluorocoxib Q-H that results in high signal-to-noise contrast and differentiates pathologic tissues from non-pathologic tissues for real-time in vivo imaging.

Histone Methyltransferase KMT2D Regulates H3K4 Methylation and is Involved in the Pathogenesis of Ovarian Cancer

To investigate the function of histone-lysine N-methyltransferase 2D (KMT2D) on the methylation of H3 lysine 4 (H3K4) in the progression of Ovarian cancer (OV). KMT2D, ESR1 and H3K4me expressions in surgical resected tumors and tumor adjacent tissues of OV from 198 patients were determined using immunohistochemistry (IHC). Human OV cell lines including SKOV3, HO-8910 cells and normal ovarian epithelial cell line IOSE80 were employed for in vitro experiment, and BALB/C female nude mice were used for in vivo study. qRT-PCR and Western blotting were implemented for measuring the KMT2D, ESR1, PTGS2, STAT3, VEGFR2, H3K4me and ELF3 levels. Chromatin immunoprecipitation (ChIP) analysis was used for studying the binding between ESR1 and H3K4me. Edu staining assay was executed to determine cell viability, and colony formation and cell invasion assay. The immunofluorescence method was utilized for the visualization of protein expression and distribution in cells. In this study, KMT2D, ESR1 and H3K4me were found upregulated in OV progression. Mutated H3K4me could inhibit the proliferation, colony formation and invasion ability of OV cells. Mutated H3K4me could also hinder the ESR1 in SKOV3 expressions and HO-8910 cells, which would further mediate PTGS2/STAT3/VEGF pathway. In vivo studies also demonstrated that mutated H3K4me inhibited OV progression via targeting ESR1. All the ChIP-PCR analysis indicated the moderator effect of H3K4me on ESR1. Our findings indicated that ESR1 played an important role in the OV progression. Besides, H3K4me could promote cell proliferation and inhibit apoptosis of OV cells. Meanwhile, it could also targets the ESR1 production to enhance the migration and invasion of OV cells, which was through the activation of ESR1-ELF3-PTGS2-STAT3-VEGF cascade signaling pathway.

Pre-clinical investigation of STAT3 pathway in bladder cancer: Paving the way for clinical translation

Effective cancer therapy requires identification of signaling networks and investigating their potential role in proliferation and invasion of cancer cells. Among molecular pathways, signal transducer and activator of transcription 3 (STAT3) has been of importance due to its involvement in promoting proliferation, and invasion of cancer cells, and mediating chemoresistance. In the present review, our aim is to reveal role of STAT3 pathway in bladder cancer (BC), as one of the leading causes of death worldwide. In respect to its tumor-promoting role, STAT3 is able to enhance the growth of BC cells via inhibiting apoptosis and cell cycle arrest. STAT3 also contributes to metastasis of BC cells via upregulating of MMP-2 and MMP-9 as well as genes in the EMT pathway. BC cells obtain chemoresistance via STAT3 overexpression and its inhibition paves the way for increasing efficacy of chemotherapy. Different molecular pathways such as KMT1A, EZH2, DAB2IP and non-coding RNAs including microRNAs and long non-coding RNAs can function as upstream mediators of STAT3 that are discussed in this review article.

Dysregulation of HULC promotes contrast-induced nephropathy (CIN) via regulating signaling pathway of miRNA-512 and prostaglandin E1 (PGE1)

It has been shown that contrast-induced nephropathy (CIN) can be attenuated by the administration of PGE1. As an enzyme responsible for the production of PGE1, PTGS1 was confirmed in this study as a miR-512 target. Meanwhile, HULC has been identified as a competing endogenous RNA of miR-512. Therefore, in this study, we tested the diagnostic value of HULC and miR-512 in subjects with or without CIN. In addition, we evaluated the regulatory relationship among HULC, miR-512, PTGS1 and PGE1 in vitro. We enrolled 320 patients with coronary heart disease and divided them into a CIN group and a non-CIN group. Subsequently, we detected the differential expression of miR-512, HULC and PGE1 in the two groups. We also used a dual luciferase reporter assay to evaluate the regulatory relationship among HULC, miR-512, PTGS1 and PGE1 in THP-1 cells. In patients with CIN, the expression levels of HULC and PGE1 were lower, but the expression level of miR-512 was higher. MiR-512 could directly bind to and negatively regulate the expression of PTGS1 and HULC. The expression of HULC was positively correlated with the expression of PTGS1 and PGE1, while negatively correlated with the expression of miR-512. The findings of this study demonstrated that deregulation of lncRNA-HULC/miR-512/PTGS1/PGE1 might be involved in the pathogenesis of CIN.

Cyclooxygenase 2 Promotes Proliferation and Invasion in Ovarian Cancer Cells via the PGE2/NF-κB Pathway

Ovarian cancer is the leading cause of death among gynecological malignancies. Cyclooxygenase 2 is widely expressed in various cancer cells and participates in the occurrence and development of tumors by regulating a variety of downstream signaling pathways. However, the function and molecular mechanisms of cyclooxygenase 2 remain unclear in ovarian cancer. Here, we demonstrated that cyclooxygenase 2 was highly expressed in ovarian cancer and the expression level was highly correlated with ovarian tumor grades. Further, ovarian cancer cells with high expression of cyclooxygenase 2 exhibit enhanced proliferation and invasion abilities. Specifically, cyclooxygenase 2 promoted the release of prostaglandin E2 upregulated the phosphorylation levels of phospho-nuclear factor-kappa B p65. Celecoxib, AH6809, and BAY11-7082 all can inhibit the promoting effect of cyclooxygenase 2 on SKOV3 and OVCAR3 cell proliferation and invasion. Besides, celecoxib inhibited SKOV3 cell growth in the xenograft tumor model. These data suggest that high expression of cyclooxygenase 2 promotes the proliferation and invasion of ovarian cancer cells through the prostaglandin E2/nuclear factor-kappa B signaling pathway. Cyclooxygenase 2 may be a potential therapeutic target for the treatment of ovarian cancer.

Understanding the Interplay between COX-2 and hTERT in Colorectal Cancer Using a Multi-Omics Analysis

Background: Cyclooxygenase 2 (COX-2) is involved in the initial steps of colorectal cancer (CRC) formation, playing a key role in the catalysis of arachidonic acid to prostaglandin E2 (PGE₂). The human telomerase reverse transcriptase (hTERT or TERT) also plays an important role in colorectal cancer growth, conferring sustained cell proliferation and survival. Although hTERT induces COX-2 expression in gastric and cervical cancer, their interaction has not been investigated in the context of CRC. Methods: COX-2, PGE₂ levels, and telomerase activity were evaluated by immunohistochemistry, ELISA, and TRAP assay in 49 colorectal cancer samples. PTGS1, PTGS2, PTGES3, TERT mRNA, and protein levels were investigated using RNA-seq and antibody-based protein profiling data from the TCGA and HPA projects. A multi-omics comparison was performed between PTGS2 and TERT, using RNAseq, DNA methylation, copy number variations (CNVs), single nucleotide polymorphisms (SNPs), and insertions/deletions (Indels) data. Results: COX-2 expression was positive in 40/49 CRCs, bearing cytoplasmic and heterogeneous staining, from moderate to high intensity. COX-2 staining was mainly detected in the stroma of the tumor cells and the adjacent normal tissues. PGE₂ expression was lower in CRC compared to the adjacent normal tissue, and inversely correlated to telomerase activity in right colon cancers. COX-1 and COX-2 were anticorrelated with TERT. Isoform structural analysis revealed the most prevalent transcripts driving the differential expression of PTGS1, PTGS2, PTGES3, and TERT in CRC. COX-2 expression was significantly higher among B-Raf proto-oncogene, serine/threonine kinase, mutant (BRAF^mut) tumors. Kirsten ras oncogene (KRAS) mutations did not affect COX-2 or TERT expression. The promoter regions of COX-2 and TERT were reversely methylated. Conclusions: Our data support that COX-2 is involved in the early stages of colorectal cancer development, initially affecting the tumor’s stromal microenvironment, and, subsequently, the epithelial cells. They also highlight an inverse correlation between COX-2 expression and telomerase activity in CRC, as well as differentially methylated patterns within the promoter regions of COX-2 and TERT.

Association of Cyclooxygenase-2 Immunoreactivity with Tumor Recurrence and Disease Progression in Superficial Urothelial Bladder Cancer

Aims and Background

The main characteristic of urothelial bladder cancer is a clear predisposition to recurrence and disease progression. The aim of this study was to assess the possible relationship between cyclooxygenase-2 (COX-2) immunoreactivity in superficial urothelial bladder carcinoma and tumor grade, stage, number of recurrences and clinical disease progression.

Methods

In this prospective study 70 consecutive patients who underwent transurethral resection for superficial urothelial bladder cancer were included. Tumor slides were immuno-histochemically stained for COX-2, and COX-2 immunoreactivity in tumor and inflammatory stromal cells was categorized as negative or mildly, moderately or strongly positive. Patients were followed up for 2 years, and during this period the possible association of COX-2 immunoreactivity with tumor stage and grade, number of recurrences and progression of disease was evaluated.

Results

COX-2 immunoreactivity in tumor cells was found in 57 (81.4%) patients and did not correlate with tumor grade, stage of disease, number of recurrences, and progression of disease. COX-2 immunoreactivity in inflammatory cells was found in 16 of the 57 patients with COX-2 positive tumors, and was significantly related to the number of recurrences, time to appearance of the first recurrence, and disease progression.

Conclusions

COX-2 immunoreactivity in inflammatory stromal cells adjacent to the COX-2-positive tumor might be useful in clinical practice for selection of patients with a high risk of tumor recurrence and disease progression.

Celecoxib inhibits the epithelial-to-mesenchymal transition in bladder cancer via the miRNA-145/TGFBR2/Smad3 axis

Celecoxib, a selective cyclooxygenase-2 inhibitor, has chemo-preventive activity against different cancer types, including bladder cancer (BC). However, the mechanisms by which celecoxib exerts its cancer preventative effects have yet to be completely understood. In the present study, the effect of celecoxib on the epithelial-to-mesenchymal transition (EMT) of BC cells and its potential molecular mechanisms were investigated. The results of the present study demonstrated that celecoxib inhibited the proliferation, migration, invasion and EMT of BC cells. Further investigation of the underlying mechanism revealed that celecoxib inhibited EMT by upregulating microRNA (miR)-145 and downregulating the expression of transforming growth factor β receptor 2 and SMAD family member 3. Furthermore, the combination of celecoxib with miR-145 mimics demonstrated an additive migration and invasion-inhibitory effect in BC cell lines.

Increased COX-2 Immunostaining in Urothelial Carcinoma of the Urinary Bladder Is Associated with Invasiveness and Poor Prognosis

BACKGROUND

Urothelial carcinoma of the urinary bladder (UCB) is the commonest bladder tumor. Cyclooxygenase-2 (COX-2) mediates angiogenesis, cell survival/proliferation, and apoptosis. This study investigates the relation of COX-2 immunostaining in UCB to clinicopathological parameters in Saudi Arabia.

METHODS

The study population includes 123 UCB and 25 urothelial mucosae adjacent to UCB. UCB samples were collected before any local or systemic therapy. Tissue microarrays were designed and constructed, and TMA blocks were sliced for further immunohistochemical staining. Immunohistochemical staining was done using a mouse anti-human COX-2 monoclonal antibody. A cutoff point of 10% was chosen as the threshold to determine low and high COX-2 immunostaining.

RESULTS

COX-2 immunostaining is higher in UCB than in the adjacent urothelium (p = 0.033). High COX-2 immunostaining is associated with high-grade UCB (p = 0.013), distant metastasis (p = 0.031), lymphovascular invasion (p = 0.008), positive muscle invasion (p = 0.017), pT2 and above (p = 0.003), and high anatomical stages (stage II and above). High COX-2 immunostaining is an independent predictor of higher tumor grade (p < 0.001), muscle invasion (p = 0.015), advanced pathological T (p = 0.014), lymphovascular invasion (p = 0.011), and distant metastasis (p = 0.039). High COX-2 immunostaining is associated with lower overall survival rate (p = 0.019).

CONCLUSION

COX-2 immunostaining is associated with the invasiveness of UCB which may be used as an independent prognostic marker. COX-2 may be a significant molecule in the initiation and progression of UCB. Molecular and clinical investigations are required to explore the molecular downstream of COX-2 in UCB and effectiveness of COX-2 inhibitors as adjuvant therapy along with traditional chemotherapy.

Cancer stem cells and epithelial-mesenchymal transition in urothelial carcinoma: Possible pathways and potential therapeutic approaches

There is growing evidence of the presence of cancer stem cells in urothelial carcinoma. Cancer stem cells have the ability to self-renew and to differentiate into all cell types of the original heterogeneous tumor. A panel of diverse cancer stem cell markers might be suitable for simulation studies of urothelial cancer stem cells and for the development of optimized treatment protocols. The present review focuses on the advances in recognizing the markers of urothelial cancer stem cells and possible therapeutic targets. The commonly reported markers and pathways that were evaluated include CD44, CD133, ALDH1, SOX2 & SOX4, BMI1, EZH1, PD-L1, MAGE-A3, COX2/PGE2/STAT3, AR, and autophagy. Studies on the epithelial-mesenchymal transition-related pathways (Shh, Wnt/β-catenin, Notch, PI3K/Akt, TGF-β, miRNA) are also reviewed. Most of these markers were recognized through the expression patterns of cancer stem cell-rich side populations. Their regulative role in the development and differentiation of urothelial cancer stem cells was confirmed in vitro by functional analyses (e.g. cell migration, colony formation, sphere formation), and in vivo in xenograft experiments. Although a small number of these pathways are targeted by currently available drugs or drugs that are the currently being tested in clinical trials, a clear treatment approach has not been developed for most pathways. A greater understanding of the mechanisms that control the proliferation and differentiation of cancer stem cells is expected to lead to improvements in targeted therapy.

Metformin represses bladder cancer progression by inhibiting stem cell repopulation via COX2/PGE2/STAT3 axis

Cancer stem cells (CSCs) are a sub-population of tumor cells playing essential roles in initiation, differentiation, recurrence, metastasis and development of drug resistance of various cancers, including bladder cancer. Although multiple lines of evidence suggest that metformin is capable of repressing CSC repopulation in different cancers, the effect of metformin on bladder cancer CSCs remains largely unknown. Using the N-methyl-N-nitrosourea (MNU)-induced rat orthotropic bladder cancer model, we demonstrated that metformin is capable of repressing bladder cancer progression from both mild to moderate/severe dysplasia lesions and from carcinoma in situ (CIS) to invasive lesions. Metformin also can arrest bladder cancer cells in G1/S phases, which subsequently leads to apoptosis. And also metformin represses bladder cancer CSC repopulation evidenced by reducing cytokeratin 14 (CK14+) and octamer-binding transcription factor 3/4 (OCT3/4+) cells in both animal and cellular models. More importantly, we found that metformin exerts these anticancer effects by inhibiting COX2, subsequently PGE2 as well as the activation of STAT3. In conclusion, we are the first to systemically demonstrate in both animal and cell models that metformin inhibits bladder cancer progression by inhibiting stem cell repopulation through the COX2/PGE2/STAT3 axis.

Celecoxib for the prevention of nonmuscle invasive bladder cancer: results from a matched control study

OBJECTIVES

New targets and approaches are under investigation for the treatment of nonmuscle invasive bladder cancer (NMIBC). Preclinical data suggest cyclooxygenase-2 (COX-2) as a promising target. Celecoxib, a COX-2 selective inhibitor, inhibits tumor development and enhances survival, both in vitro and in vivo models of bladder cancer. Therefore, we conducted a pilot study of celecoxib to prevent recurrence in patients with intermediate risk NMIBC.

METHODS

Treatment with celecoxib was administered orally for 12 months and compared with a contemporary series of patients treated with intravesical mitomycin C (MMC), given weekly for 4 weeks and then monthly for 11 months. Primary endpoints were time to first recurrence and adverse events.

RESULTS

From 2003 through 2006, 58 patients were treated with celecoxib and compared with 66 patients receiving MMC. After a median follow up of 75 months, 49 patients were disease free, including 23 (34.85%) in the MMC group and 26 (44.8%) in the celecoxib group. Median disease-free interval was 67 months [95% confidence interval (CI) 35.8 to NA] versus 41 months (95% CI 27.1-67.1; log-rank p = 0.25) for patients treated with MMC and celecoxib, respectively. In the multivariate analysis, treatment was not found to be an independent predictor for recurrence [hazard ratio (HR) 0.76, 95% CI 0.47-1.22, p = 0.25). Overall, 45 AEs were recorded in 35/124 patients. There were no differences between the two groups.

CONCLUSIONS

Our data support a clinical benefit of celecoxib and encourage future trials in which COX-2 inhibitors may be tested in selected patients with NMIBC.

Antiproliferative and anti-inflammatory properties of diindolylmethane and lupeol against N-butyl-N-(4-hydroxybutyl) nitrosamine induced bladder carcinogenesis in experimental rats

INTRODUCTION

Chemoprevention may involve perturbation of a variety of steps in tumor initiation, promotion, and progression.

OBJECTIVE

To investigate the antiproliferative and anti-inflammatory potential effects of diindolylmethane (DIM) and lupeol on experimental bladder carcinogenesis.

METHODS

Sixty healthy male Wistar rats were selected and randomly divided into six groups, with 10 rats in each group. Group I: control; group II: N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN; 150 mg/gavage/twice a week) for 8 weeks, and then they were given 100 ppm concentrations of dimethylarsenic acid (DMA) in the drinking water for 28 weeks; group III: BBN + DMA + DIM (5 mg/kg body weight (b.w.)/day) treatment was started after BBN treatment, and it was orally administered for 28 weeks); group IV: BBN + DMA + lupeol (50 mg/kg b.w./day) treatment was started after BBN treatment, and it was orally administered for 28 weeks); and groups V and VI: DIM and lupeol treatment alone for 36 weeks. Bladder tissues were collected after 36th week study protocol for further analysis.

RESULTS

Our results revealed that DIM and lupeol treatment showed inhibition of tumor growth in the bladder by histopathological confirmations as well as significantly (p < 0.001) increased the expression of phosphotensin (PTEN) and significantly (p < 0.001) decreased the expression of tumor necrosis factor α, nuclear factor κβ (p65) were quantified using Western blot analysis. DIM and lupeol treatment significantly (p < 0.001) decreased the levels of Cox-2 in bladder tissue samples and NMP 22 in urine samples were quantified using enzyme-linked immunosorbent assay method.

CONCLUSION

Preventive DIM and lupeol administration act as potent Cox-2 inhibitors, which activates the tumor suppressor protein PTEN against experimental bladder carcinogenesis by antiproliferative and anti-inflammatory properties.

Increase in cyclooxygenase-2 (COX-2) expression in keratinocytes and dermal fibroblasts in photoaged skin

BACKGROUND

Interleukins and NFκ-B are involved in the development of inflammatory reactions. It has been suggested that these proteins are important contributing factors in the process of photoaging of skin. Moreover, interleukins and NFκ-B are known to be capable of inducing expression of cyclooxygenase 2 (COX-2). Expression of COX-2 in various populations of skin cells has not been examined in the specific processes of aging.

OBJECTIVES

The study aimed at evaluating COX-2 expression in skin samples originating from patients with chronologically aged and photoaged skin at various stages of skin aging.

METHODS

Immunohistochemical analysis of COX-2 reactivity was conducted on samples originating from 52 women undergoing surgery for reasons other than skin pathology.

RESULTS

Our study demonstrated that COX-2 expression in keratinocytes and fibroblasts was significantly higher in skin samples affected by photoaging than in samples affected by endogenous aging or obtained from younger individuals.

CONCLUSIONS

The results indicate that COX-2 may be involved in the pathogenesis of the photoaging process. Inhibition of expression or activity of the enzyme may find application in photoaging treatment and/or prophylaxis.

Identification of human cyclooxegenase-2 inhibitors from Cyperus scariosus (R.Br) rhizomes

Cyperus scariosus (R.Br) belongs to the family Cyperaceae and it has a diverse medicinal importance. To identify human cyclooxegenase-2 (COX-2) inhibitors from C. scariosus, the rhizome powder was exhaustively extracted with various solvents based on the increasing polarity. Based on the presence and absence of secondary metabolites, we have selected the methanolic extract to evaluate the anti-oxidant and anti-inflammatory activity. The same extract was further subjected to gas chromatography-mass spectroscopy (GC-MS) analysis to identify the active compounds. Binding affinities of these compounds towards anti-inflammatory protein COX-2 were analyzed using molecular docking interaction studies. Phytochemical analysis showed that methanol extract is positive for all secondary metabolites. The antioxidant activity of the C. scariosus rhizomes methanolic extract (CSRME) is half to that of ascorbic acid at 50 µg/ml. The anti-inflammatory activity of CSRME is higher than that of diclofenac sodium salt at high concentration, which is evident from the dose dependent inhibition of bovine serum albumin denaturation at 40 µg/ml-5 mg/ml. GC-MS analysis showed the presence of nine compounds, among all N-methyl-1-adamantaneacetamide and 1,5,diphenyl-2H-1,2,4- triazine form a hydrogen bond interactions with Ser-530 and Tyr-385 respectively and found similar interactions with crystal structure of diclofenac bound COX-2 protein. Benzene-1, 2-diol, 4-(4-bromo-3 chlorophenyl iminomethyl forms hydrogen bond interactions with Thr-199 and Thr-200 as similar to crystallized COX-2 protein with valdecoxib. Collectively our results suggest that CSRME contains medicinally important anti-inflammatory compounds and this justifies the use of this plant as a folklore medicine for preventing inflammation associated disorders.

COX-2 overexpression in resected pancreatic head adenocarcinomas correlates with favourable prognosis

Background

Overexpression of cyclooxygenase-2 (COX-2) has been implicated in oncogenesis and progression of adenocarcinomas of the pancreatic head. The data on the prognostic importance of COX expression in these tumours is inconsistent and conflicting. We evaluated how COX-2 overexpression affected overall postoperative survival in pancreatic head adenocarcinomas.

Methods

The study included 230 consecutive pancreatoduodenectomies for pancreatic cancer (PC, n = 92), ampullary cancer (AC, n = 62) and distal bile duct cancer (DBC, n = 76). COX-2 expression was assessed by immunohistochemistry. Associations between COX-2 expression and histopathologic variables including degree of differentiation, histopathologic type of differentiation (pancreatobiliary vs. intestinal) and lymph node ratio (LNR) were evaluated. Unadjusted and adjusted survival analysis was performed.

Results

COX-2 staining was positive in 71% of PC, 77% in AC and 72% in DBC. Irrespective of tumour origin, overall patient survival was more favourable in patients with COX-2 positive tumours than COX-2 negative (p = 0.043 in PC, p = 0.011 in AC, p = 0.06 in DBC). In tumours of pancreatobiliary type of histopathological differentiation, COX-2 expression did not significantly affect overall patient survival. In AC with intestinal differentiation COX-2 expression significantly predicted favourable survival (p = 0.003). In PC, COX-2 expression was significantly associated with high degree of differentiation (p = 0.002). COX-2 and LNR independently predicted good prognosis in a multivariate model.

Conclusions

COX-2 is overexpressed in pancreatic cancer, ampullary cancer and distal bile duct cancer and confers a survival benefit in all three cancer types. In pancreatic cancer, COX-2 overexpression is significantly associated with the degree of differentiation and independently predicts a favourable prognosis.

Cyclooxygenase-2 expression in urinary bladder transitional cell carcinoma and its association with clinicopathological characteristics

BACKGROUND

Transitional cell carcinoma (TCC) is the most predominant type of urinary bladder tumor. As cyclooxygenase (COX)-2 is recently introduced as an attractive target molecule in bladder TCC, we evaluated the immunohistochemical expression of this marker and its association with several clinicopathological characteristics.

MATERIALS AND METHODS

This cross-sectional study was performed in the Pathology department of Sina Hospital in Tehran, Iran during 2006-2011. Ninety-two paraffin embedded blocks were selected from patients with urinary bladder TCC who underwent cystectomy or transurethral resection (TUR). Then, we assessed COX-2 expression by immunohistochemical staining using antibody against COX-2. Staining in more than 5% of tumor cells was considered as positive expression.

RESULTS

COX-2 was expressed in 50 % of our patients. This marker was markedly expressed in high grade bladder TCC (62.1%) versus other grades and there was statistically a significant difference in COX-2 expression between various grades (p=0.008). In addition, patients' age, lymphatic and perineurial invasion were associated with the expression of COX-2 (p=0.001, 0.015 and 0.039, respectively). However, other parameters such as stage, tumor size, venous invasion and lymph node metastasis did not show any significant relationship with this marker (all, p>0.05).

CONCLUSIONS

COX-2 was expressed in urinary bladder TCC especially in high grade forms, advocating its probable role in the differentiation of this tumor. Accordingly, COX-2 could be a valuable biological target molecule in the evaluation and treatment of patients with bladder TCC.

Differences in Expression of Uroplakin III, Cytokeratin 7, and Cyclooxygenase-2 in Canine Proliferative Urothelial Lesions of the Urinary Bladder

The expression of immunohistochemical markers that have been used in diagnosis and/or prognostication of urothelial tumors in humans (uroplakin III [UPIII], cytokeratin 7 [CK7], cyclooxygenase-2 [COX-2], and activated caspase 3) was evaluated in a series of 99 canine proliferative urothelial lesions of the urinary bladder and compared to the lesion classification and grade as defined by the World Health Organization / International Society of Urologic Pathology consensus system. There were significant associations between tumor classification and overall UPIII pattern ( P = 1.49 × 10–18), loss of UPIII ( P = 1.27 × 10–4), overall CK7 pattern ( P = 4.34 × 10–18), and COX-2 pattern ( P = 8.12 × 10–25). In addition, there were significant associations between depth of neoplastic cell infiltration into the urinary bladder wall and overall UPIII pattern ( P = 1.54 × 10–14), loss of UPIII ( P = 2.07 × 10–4), overall CK7 pattern ( P = 1.17 × 10–13), loss of CK7 expression ( P = .0485), and COX-2 pattern ( P = 8.23 × 10–21). There were no significant associations between tumor classification or infiltration and caspase 3 expression pattern.

A dynamic interplay between alternative polyadenylation and microRNA regulation: implications for cancer (Review)

Alternative polyadenylation and microRNA regulation are both mechanisms of post-transcriptional regulation of gene expression. Alternative polyadenylation often results in mRNA isoforms with the same coding sequence but different lengths of 3' UTRs, while microRNAs regulate gene expression by binding to specific mRNA 3' UTRs. In this sense, different isoforms of an mRNA may be differentially regulated by microRNAs, sometimes resulting in cellular proliferation and this mechanism is being speculated on as a potential cause for cancer development.

Inhibition of bladder tumor growth by chitooligosaccharides in an experimental carcinogenesis model

Urinary bladder cancer is one of the most common cancers worldwide, with the highest incidence in industrialized countries. Patients with cancer commonly use unconventional and complementary therapy including nutraceuticals. In this study we evaluated the efficacy of chitooligosaccharides (in orange juice) in rat bladder cancer chemoprevention and as therapeutic agent, on a rat model of urinary bladder carcinogenesis induced with N-butyl-N-(4-hydroxybutyl) nitrosamine. Results indicate that chitooligosaccharides may have a preventive effect on bladder cancer development and a curative effect upon established bladder tumors, dependent on the concentration ingested 500 mg/kg b.w., every three days, showed capacity to inhibit and prevent the proliferation of bladder cancer; however, this was associated with secondary effects such as hypercholesterolemia and hypertriglyceridemia. The use of lower doses (50 and 250 mg/kg b.w.) showed only therapeutic effects. It is further suggested that this antitumor effect might be due to its expected anti-inflammatory action, as well as by mechanisms not directly dependent of COX-2 inhibition, such as cellular proliferation control and improvement in antioxidant profile.

New therapeutic targets in the management of urothelial carcinoma of the bladder

Urothelial carcinoma of the bladder, despite the myriad of treatment approaches and our progressively increasing knowledge into its disease processes, remains one of the most clinically challenging problems in modern urological clinical practice. New therapies target biomolecular pathways and cellular mediators responsible for regulating cell growth and metabolism, both of which are frequently overexpressed in malignant urothelial cells, with the intent of inducing cell death by limiting cellular metabolism and growth, creating an immune response, or selectively delivering or activating a cytotoxic agent. These new and novel therapies may offer a potential for reduced toxicity and an encouraging hope for better treatment outcomes, particularly for a disease often refractory or not amenable to the current therapeutic approaches.

Cyclooxygenase-2 expression in bladder cancer and patient prognosis: results from a large clinical cohort and meta-analysis

Aberrant overexpression of cyclooxygenase-2 (COX2) is observed in urothelial carcinoma of the bladder (UCB). Studies evaluating COX2 as a prognostic marker in UCB report contradictory results. We determined the prognostic potential of COX2 expression in UCB and quantitatively summarize the results with those of the literature through a meta-analysis. Newly diagnosed UCB patients recruited between 1998–2001 in 18 Spanish hospitals were prospectively included in the study and followed-up (median, 70.7 months). Diagnostic slides were reviewed and uniformly classified by expert pathologists. Clinical data was retrieved from hospital charts. Tissue microarrays containing non-muscle invasive (n = 557) and muscle invasive (n = 216) tumours were analyzed by immunohistochemistry using quantitative image analysis. Expression was evaluated in Cox regression models to assess the risk of recurrence, progression and disease-specific mortality. Meta-hazard ratios were estimated using our results and those from 11 additional evaluable studies. COX2 expression was observed in 38% (211/557) of non-muscle invasive and 63% (137/216) of muscle invasive tumors. Expression was associated with advanced pathological stage and grade (p<0.0001). In the univariable analyses, COX2 expression - as a categorical variable - was not associated with any of the outcomes analyzed. As a continuous variable, a weak association with recurrence in non-muscle invasive tumors was observed (p-value = 0.048). In the multivariable analyses, COX2 expression did not independently predict any of the considered outcomes. The meta-analysis confirmed these results. We did not find evidence that COX2 expression is an independent prognostic marker of recurrence, progression or survival in patients with UCB.

FGFR1-induced epithelial to mesenchymal transition through MAPK/PLCγ/COX-2-mediated mechanisms

Tumour invasion and metastasis is the most common cause of death from cancer. For epithelial cells to invade surrounding tissues and metastasise, an epithelial-mesenchymal transition (EMT) is required. We have demonstrated that FGFR1 expression is increased in bladder cancer and that activation of FGFR1 induces an EMT in urothelial carcinoma (UC) cell lines. Here, we created an in vitro FGFR1-inducible model of EMT, and used this model to identify regulators of urothelial EMT. FGFR1 activation promoted EMT over a period of 72 hours. Initially a rapid increase in actin stress fibres occurred, followed by an increase in cell size, altered morphology and increased migration and invasion. By using site-directed mutagenesis and small molecule inhibitors we demonstrated that combined activation of the mitogen activated protein kinase (MAPK) and phospholipase C gamma (PLCγ) pathways regulated this EMT. Actin stress fibre formation was regulated by PLCγ activation, and was also important for the increase in cell size, migration and altered morphology. MAPK activation regulated migration and E-cadherin expression, indicating that combined activation of PLCγ and MAPK is required for a full EMT. We used expression microarrays to assess changes in gene expression downstream of these signalling cascades. COX-2 was transcriptionally upregulated by FGFR1 and caused increased intracellular prostaglandin E(2) levels, which promoted migration. In conclusion, we have demonstrated that FGFR1 activation in UC cells lines promotes EMT via coordinated activation of multiple signalling pathways and by promoting activation of prostaglandin synthesis.

Nuclear localization of COX-2 in relation to the expression of stemness markers in urinary bladder cancer

Inflammation may activate stem cells via prostaglandin E2 (PGE2) production mediated by cyclooxygenase-2 (COX-2) expression. We performed an immunohistochemical analysis of the expression of stemness markers (Oct3/4 and CD44v6) and COX-2 in urinary bladder tissues obtained from cystitis and cancer patients with and without Schistosoma haematobium infections. Immunoreactivity to Oct3/4 was significantly higher in S. haematobium-associated cystitis and cancer tissues than in normal tissues. CD44v6 expression was significantly higher in bladder cancer without S. haematobium than in normal tissues. COX-2 was located in the cytoplasmic membrane, cytoplasm, and nucleus of the cancer cells. Interestingly, the nuclear localization of COX-2, which was reported to function as a transcription factor, was significantly associated with the upregulation of Oct3/4 and CD44v6 in bladder cancer tissues with and without S. haematobium infection, respectively. COX-2 activation may be involved in inflammation-mediated stem cell proliferation/differentiation in urinary bladder carcinogenesis.

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.

A randomized controlled trial of celecoxib to prevent recurrence of nonmuscle-invasive bladder cancer

Significant morbidity and expense result from frequent recurrences of nonmuscle-invasive bladder cancer (NMIBC) after standard treatment, and carcinoma in situ (Tis) is a poor prognostic factor. Predicated on observational and preclinical data strongly supporting cyclooxygenase-2 (COX-2) in the pathogenesis, and the activity of COX-2 inhibitors, in bladder cancer, we conducted a randomized, double-blind, placebo-controlled trial to determine whether celecoxib could reduce the time-to-recurrence (TTR) in NMIBC patients at high risk for recurrence. A total of 146 patients were randomized to celecoxib (200 mg) or placebo orally twice daily for at least 12 months. The average treatment duration was 1.25 years. Primary intent-to-treat analysis revealed celecoxib did not statistically significantly prolong TTR compared with placebo (P = 0.17, log rank) with a median follow-up of 2.49 years. The recurrence-free rate at 12 months with celecoxib was 88% (95% CI: 0.81-0.96) versus 78% (95% CI: 0.69-0.89) with placebo. After controlling for covariates with Cox regression analysis, recurrence rates did not differ between the two study arms (HR = 0.69; 95% CI: 0.37-1.29). However, celecoxib had a marginally significant effect on reducing metachronous recurrences (vs. placebo) with HR of 0.56 (95% CI: 0.3-1.06; P = 0.075). Celecoxib was well tolerated, with similar adverse events and quality-of-life in both arms. Our clinical trial results do not show a clinical benefit for celecoxib in preventing NMIBC recurrence but further investigation of COX-2 inhibitors in this setting is warranted.

Pathobiology and chemoprevention of bladder cancer

Our understanding of the pathogenesis of bladder cancer has improved considerably over the past decade. Translating these novel pathobiological discoveries into therapies, prevention, or strategies to manage patients who are suspected to have or who have been diagnosed with bladder cancer is the ultimate goal. In particular, the chemoprevention of bladder cancer development is important, since urothelial cancer frequently recurs, even if the primary cancer is completely removed. The numerous alterations of both oncogenes and tumor suppressor genes that have been implicated in bladder carcinogenesis represent novel targets for therapy and prevention. In addition, knowledge about these genetic alterations will help provide a better understanding of the biological significance of preneoplastic lesions of bladder cancer. Animal models for investigating bladder cancer development and prevention can also be developed based on these alterations. This paper summarizes the results of recent preclinical and clinical chemoprevention studies and discusses screening for bladder cancer.

RGD-modified endostatin peptide 30 derived from endostatin suppresses invasion and migration of HepG2 cells through the αvβ3 pathway

The nucleotide sequence encoding amino acids 1-30 of endostatin (peptide 30, with amino acids 25-31 mutated from RGIRGAD to RGDRGD) was artificially synthesized and cloned into the plasmid pTYB2 and expressed in Escherichia coli (DE3). Peptide 30 was purified by chitin affinity chromatography followed by dithiothreitol removal by gel filtration and protein identification using Tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Similarly, peptide 27, corresponding to amino acids 1-27 of endostatin, was produced as control. The effects of peptide 30 on the metastatic potential of HepG2 cells were then investigated. Peptide 30 was found to effectively suppress the adhesion, invasion, and migration of HepG2 cells. Flow cytometry demonstrated that peptide 30 did not alter the expression of membrane integrin αvβ3, although immunofluorescent staining revealed that these integrins formed clusters on the cell surface. Therefore, the effects of peptide 30 on cancer cell invasion may involve the αvβ3 pathway. Moreover, peptide 30 inactivated metalloproteinase-2 (MMP-2) and MMP-9 and downregulated the expression of COX-2 (cyclooxygenase 2), MMP-2, and MMP-9 at both mRNA and protein levels. Peptide 30 also upregulated the expression of tissue inhibitor of metalloproteinase-1 and tissue inhibitor of metalloproteinase-2 at mRNA and protein levels. Lastly, an antibody against αvβ3 enhanced the biological effects of peptide 30.

Correlation of E-cadherin, VEGF, COX-2 expression to prognostic parameters in papillary thyroid carcinoma

Thyroid cancer represents approximately 1% of all human malignancies. papillary thyroid carcinoma (PTC) is the most common malignant tumor of the thyroid gland, accounting for 70-80% of all thyroid cancers. In the US, the incidence of thyroid cancer is 4 per 100,000 individuals. It is two to four times as frequent in women as in men. The development of PTC is influenced by many factors including genetic alterations, growth factors, and physical agents such as radiation. In order to recognize the prognosis for PTC, a lot of clinic and pathological parameters such as; age, tumor size, extra-thyroid tumor spread, lymph node, distant metastases, gender, tumor stage are used. As most of these parameters are subjective, more objective and useful prognostic factors are needed for determining biologic behavior, providing an initial assessment. In this study, we aimed to compare the expressions of COX-2, E-cadherin, VEGF to classical prognostic factors, and to investigate the correlation with prognosis. Operation records from 79 PTC cases were examined retrospectively. In the study, we aimed to investigate the whole tissue by means of stereology method, which is an impartial one, and we indicated the expression COX-2, VEGF, E-cadherin immunohistochemically in 79 resection diagnosed with PTC. We determined correlations between the expressions of COX-2 and VEGF, E-cadherin, and age, gender, and stage.

Preventive but not curative efficacy of celecoxib on bladder carcinogenesis in a rat model

To evaluate the effect of a cyclooxygenase 2 inhibitor, celecoxib (CEL), on bladder cancer inhibition in a rat model, when used as preventive versus as curative treatment. The study comprised 52 male Wistar rats, divided in 5 groups, during a 20-week protocol: control: vehicle, carcinogen: 0.05% of N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN), CEL: 10 mg/kg/day of the selective COX-2 inhibitor Celebrex, preventive CEL (CEL+BBN-P), and curative CEL (BBN+CEL-C) groups. Although tumor growth was markedly inhibited by the preventive application of CEL, it was even aggravated by the curative treatment. The incidence of gross bladder carcinoma was: control 0/8(0%), BBN 13/20(65%), CEL 0/8(0%), CEL+BBN-P 1/8(12.5%), and BBN+CEL-C 6/8(75%). The number and volume of carcinomas were significantly lower in the CEL+BBN-P versus BBN, accompanied by an ample reduction in hyperplasia, dysplasia, and papillary tumors as well as COX-2 immunostaining. In spite of the reduction of tumor volumes in the curative BBN+CEL-C group, tumor malignancy was augmented. An anti-inflammatory and antioxidant profile was encountered only in the group under preventive treatment. In conclusion, preventive, but not curative, celecoxib treatment promoted a striking inhibitory effect on bladder cancer development, reinforcing the potential role of chemopreventive strategies based on cyclooxygenase 2 inhibition.

Monomethylarsonous acid produces irreversible events resulting in malignant transformation of a human bladder cell line following 12 weeks of low-level exposure

Arsenic is a known human bladder carcinogen; however, the mechanisms underlying arsenical-induced bladder carcinogenesis are not understood. Previous research has demonstrated that exposure of a nontumorigenic human urothelial cell line, UROtsa, to 50 nM monomethylarsonous acid (MMA(III)) for 52 weeks resulted in malignant transformation. To focus research on the early mechanistic events leading to MMA(III)-induced malignancy, the goal of this research was to resolve the critical period in which continuous MMA(III) exposure (50 nM) induces the irreversible malignant transformation of UROtsa cells. An increased growth rate of UROtsa cells results after 12 weeks of MMA(III) exposure. Anchorage-independent growth occurred after 12 weeks with a continued increase in colony formation when 12-week exposed cells were cultured for an additional 12 or 24 weeks without MMA(III) exposure. UROtsa cells as early as 12 weeks MMA(III) exposure were tumorigenic in severe combined immunodeficiency mice with tumorigenicity increasing when 12-week exposed cells were cultured for an additional 12 or 24 weeks in the absence of MMA(III) exposure. To assess potential underlying mechanisms associated with the early changes that occur during MMA(III)-induced malignancy, DNA methylation was assessed in known target gene promoter regions. Although DNA methylation remains relatively unchanged after 12 weeks of exposure, aberrant DNA methylation begins to emerge after an additional 12 weeks in culture and continues to increase through 24 weeks in culture without MMA(III) exposure, coincident with the progression of a tumorigenic phenotype. Overall, these data demonstrate that 50 nM MMA(III) is capable of causing irreversible malignant transformation in UROtsa cells after 12 weeks of exposure. Having resolved an earlier timeline in which MMA(III)-induced malignant transformation occurs in UROtsa cells will allow for mechanistic studies focused on the critical biological changes taking place within these cells prior to 12 weeks of exposure, providing further evidence about potential mechanisms of MMA(III)-induced carcinogenesis.

Anti-cancer effects of celecoxib in head and neck carcinoma

Although many studies highlighted cyclooxygenase2 (COX2) inhibition as a promising therapeutic strategy for cancer, more evidence is needed for clinical application. The purpose of this study was to investigate the feasibility of COX2 inhibition as a strategic treatment modality for head and neck carcinoma (HNC). We tested COX2 inhibitor, celecoxib in six types of HNC cells and analyzed the expression changes in proteins related to angiogenesis and apoptosis in vitro. We also evaluated proliferation, gelatinolysis and in vitro invasion. We used a hamster carcinogenesis model and a mouse tumorigenesis model for the in vivo evaluation of COX2 inhibition. We performed immunohistochemistry to assess changes in the expression of COX2, survivin and angiogenesis. Celecoxib administration caused decreases in the expressions of COX2, VEGF and survivin in vitro. Proliferation, in vitro invasion and gelatinolytic activity were reduced in HNC cell lines, but the effect was inconsistent across lines. COX2 inhibition retarded oral carcinogenesis from an early carcinogenic stage with increased apoptosis and decreased survivin expression. COX2 inhibition did not inhibit tumor growth, even with the COX2 downregulation and decrease in neovascularization. We conclude that COX2 inhibition has a chemopreventive effect, but its application as a treatment of HNC in a clinical setting still requires further research to overcome its limited anti-cancer effects.

Overexpression of cyclooxygenase-2 in urothelial carcinoma in conjunction with tumor-associated-macrophage infiltration, hypoxia-inducible factor-1alpha expression, and tumor angiogenesis

This study examines whether the expression of cyclooxgenase-2 (COX-2) in urothelial carcinoma (UC) is associated with macrophage infiltration, hypoxia-inducible factor-1alpha (HIF-1alpha) expression and angiogenesis. We investigated the expression of COX-2 associated with HIF-1alpha and performed double immunohistochemical analysis of 216 UCs for COX-2 expression and the correlation with tumor-associated-macrophage (TAM) density and microvessel density (MVD) in situ. A high expression of COX-2 was positively correlated with tumor invasiveness, histologic grade and HIF-1alpha expression in UC (p<0.0001, p=0.003, p<0.0001, respectively). Quantification of double staining of COX-2/CD34 and COX-2/CD68 showed that a higher MVD and TAM density was found in COX-2 high-expression than in COX-2 low-expression tumor fields (p<0.0001). Adjacent to the principal of COX-2 expression areas, MVD value and TAM density were significantly increased in HIF-1alpha high-expression specimens compared with HIF-1alpha low-expression ones (p<0.0001). Interestingly, our data revealed that high COX-2 expression (p=0.002), high HIF-1alpha expression (p<0.0001) and TAM density (p<0.0001) were all associated with high MVD value. Our results suggest that COX-2 may produce a cooperative effect in promoting tumor progression and may be involved in the process of angiogenesis through increasing TAM infiltration or HIF-1alpha regulation by hypoxia.

Cyclooxygenase-2 expression on urothelial and inflammatory cells of cystoscopic biopsies and urine cytology as a possible predictive marker for bladder carcinoma

Cyclooxygenase-2 (COX-2) is a key inducible enzyme involved in the production of prostaglandins. It contributes to human carcinogenesis by various mechanisms. The aim of the current study was to elucidate the possible involvement of COX-2 in human bladder carcinoma by examining its expression on both urothelial and inflammatory cells in tissue biopsies and urine cytology samples of different urinary bladder lesions. A total of 65 patients were included in the study and were selected from cases admitted to Urology Department, Theodor Bilharz Research Institute (TBRI), Giza, Egypt. They represented seven control cases with almost normal-looking bladder tissue; pure chronic cystitis (n=12); premalignant lesions (18) in the form of squamous metaplasia (n=8) or urothelial dysplasia (n=10) as well as transitional cell carcinoma (TCC) (n=18), and squamous cell carcinoma (SqCC) (n=10). Immunohistochemistry of formalin-fixed, paraffin-embedded tissue sections and urine cytology samples was performed for all cases using COX-2 (H-62): sc-7951, a rabbit polyclonal antibody. The study revealed positive COX-2 expression on the urothelial and inflammatory cells of cystoscopic biopsies from all cases of pure chronic cystitis, squamous metaplasia and SqCC compared with 42.8% and 71.4% of normal controls, respectively. The score of urothelial COX-2 expression was sequentially up-regulated from normal to chronic cystitis (either pure or associated with premalignant changes) (p<0.05) to malignant changes (p<0.05). However, the inflammatory cellular expression was down-regulated with malignant transformation compared with chronic cystitis (p<0.05). In TCC, COX-2 was over-expressed on both urothelial and inflammatory cells in advanced tumors. Urine cytology samples were positive for COX-2 in a comparable manner to that observed in cystoscopic biopsies. Accordingly, the results of the current study have provided new information in two aspects: First, is the possibility of using the differential COX-2 expression on both inflammatory and urothelial cells as markers for premalignant or malignant transformation; second, besides cystoscopy, urine cytology was found to have a high sensitivity for COX-2 expression and hence proved to be valuable in malignancy as a non-invasive substitute for cystoscopy.

Regulation of the prostaglandin pathway during development of invasive bladder cancer in mice

Prostaglandin E(2) (PGE(2)) is reported to play an important role in tumor development. We explored the differential expression of genes governing production of, and response to, PGE(2) during development of invasive bladder cancer. N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN) or vehicle-treated mice (n=4-5) were euthanized after 4-8 weeks (period 1, P1), 12-16 weeks (P2), and 20-23 weeks (P3). Half of each bladder was analyzed histologically and the other half extracted for mRNA analysis by quantitative real-time PCR. Bladders from BBN-treated mice showed progression from submucosal inflammation (P1) to squamous metaplasia/focal CIS (P2) to poorly differentiated, invasive cancer (P3). mRNA levels for the inducible cyclooxygenase, COX-2, were elevated three to fourfold at all time points in BBN-treated mice compared to controls. In contrast, mRNA levels for constitutive COX-1 and cytosolic phospholipase A(2) (cPLA(2)), which releases substrate for COX, were either unchanged or decreased in BBN-treated mice relative to controls. Downstream of COX, mRNA levels of membrane-bound PGE(2) synthase (mPGES-1) were increased 1.7-fold at P1 in BBN bladders but returned to control levels at P2 and P3. mRNA levels for 15-prostaglandin dehydrogenase (PGDH), which inactivates PGE(2), were reduced 50-80% in BBN-treated bladders at all time points. mRNA levels for EP2R and EP4R, receptors for PGE(2), were two to threefold increased at P1, but returned to control levels or below at P3. Hence, increased COX-2 and decreased PDGH expression occurred throughout tumor development, while mPGES-1, EP2R and EP4R were elevated only before development of invasive cancer. We compared expression of these genes in the malignant human urothelial cell lines, HTB-5 and HT-1376, with expression in a benign urothelial cell line, UROtsa. Neither malignant cell line reproduced the complete in vivo pattern, relative to benign cells, but each showed abnormal basal expression of several of the genes downstream of COX-2, but not COX-2 itself. We conclude that components involved in PGE(2) synthesis and activity are differentially regulated during bladder tumor development and the therapeutic efficacy of targeting the various components may vary with stage of tumor development.

VEGF, COX-2, and PCNA expression in renal cell carcinoma subtypes and their prognostic value

OBJECTIVE

To evaluate the prognostic value of new markers such as VEGF (vascular endothelial growth factor), COX-2 (cyclooxygenase-2), and PCNA (proliferating cell nuclear antigen) and review their differences in expression by histological subtype in patients with renal cell carcinoma (RCC).

METHODS

About 99 patients who underwent radical (n = 79) or partial nephrectomy (n = 20) were included in this study. Histopathological specimens from the subjects were retrospectively analyzed immunohistochemically for the presence of VEGF, COX-2, or PCNA.

RESULTS

Mean staining ratios for VEGF, COX-2, and PCNA were 16.5, 16.8, and 31%, respectively. Correlations were evaluated among these three prognostic factors. There was no correlation between PCNA and VEGF (P = .068), but there were significant correlations between COX-2 and both PCNA and VEGF (P = .005 and P = .000, respectively). A significant correlation was found between the expression of VEGF and both pathologic stage and vascular invasion (P = .018 and P = .025, respectively). In addition, patients with conventional RCC had significantly lower VEGF and COX-2 levels than those with papillary RCC (P < .012).

CONCLUSIONS

It is obvious that prognostic factors such as VEGF, COX-2, and PCNA may vary depending on histological subtype. The level of expression of these factors together with histological subtype may provide valuable predictive information about the outcome of treatment.

The role of apoptosis in therapy and prophylaxis of epithelial tumours by nonsteroidal anti-inflammatory drugs (NSAIDs)

In addition to having anti-inflammatory activities, nonsteroidal anti-inflammatory drugs (NSAIDs) also inhibit neoplastic cell proliferation by inducing apoptosis. Diclofenac is the anti-neoplastic compound in diclofenac 3% gel (Solaraze) used for topical treatment of actinic keratosis (AK). Main target of NSAIDs seems to be the inhibition of cyclo-oxygenase-2 (COX-2), which is overexpressed in several epithelial tumours and catalyses the synthesis of prostaglandins. The precise mechanism of action of diclofenac in cutaneous cells is still unclear, but induction of apoptosis is a key effect of anti-neoplastic drugs, including NSAIDs. In this paper we give an overview of the anti-tumoural activities of NSAIDs with emphasis on induction of apoptosis. Cyclo-oxygenase-2-mediated synthesis of prostaglandin E(2) (PGE(2)) leads to activation of mitogen-activated protein kinase (MAPK), as well as phosphatidylinositol 3-kinase (PI3K)/Akt pathways. Induction of the anti-apoptotic Bcl-2 and Mcl-1, as well as activation of the caspase-8 inhibitor cFLIP have been reported. In addition, altered lipid concentrations in the cytoplasmic membrane may modulate death receptor activities. Downregulation of both the intrinsic mitochondrial and the extrinsic pathways have been reported. Our data demonstrate induced apoptosis and activation of the caspase cascade in three of four cutaneous squamous cell carcinoma (SCC) cell lines, after treatment with diclofenac plus hyaluronic acid and diclofenac alone; one cell line remained nonresponsive. The effects were less pronounced in normal keratinocytes and cytotoxic effects were not seen. Detailed analysis of apoptosis pathways employed by diclofenac in these cells may help to improve therapeutic strategies and to overcome possible mechanisms that are involved in nonresponsiveness.

Potent inhibition of in vivo angiogenesis and tumor growth by a novel cyclooxygenase-2 inhibitor, enoic acanthoic acid

Recent studies have shown that cyclooxygenase-2 is crucially involved in angiogenesis. In fact, several specific cyclooxygenase-2 inhibitors suppress angiogenesis in vivo, suggesting that cyclooxygenase-2 is a promising target for the treatment of angiogenesis-related diseases. In the present study we investigate the activity of a new cyclooxygenase-2 inhibitor, enoic acanthoic acid (EAA), which was synthesized from the known natural cyclooxygenase-2 inhibitor, acanthoic acid (AA). The demonstration of a high correlation between EAA- and celecoxib-induced gene expression signatures in microarray experiments validated the specificity of EAA on cyclooxygenase-2. In angiogenesis assays, EAA potently inhibited basic fibroblast growth factor-induced invasion and tube formation of bovine aortic endothelial cells in vitro. Moreover, this inhibitor prevented both neovascularization of the chorioallantoic membrane of growing chick embryo and basic fibroblast growth factor-induced mouse corneal angiogenesis in vivo. EAA also significantly suppressed the growth of bladder tumors in a mouse model, showing better antitumor activity than celecoxib. Furthermore, gelatin zymogram analysis revealed that EAA potently inhibited the activities of matrix metalloproteinase 2 and 9. These results clearly demonstrate that EAA is a promising agent for the prevention and treatment of angiogenesis-related diseases including cancer.

Non-steroidal anti-inflammatory drugs in the treatment of genitourinary malignancies: focus on clinical data

The antitumour activity of NSAIDs in preclinical trials has lead to their evaluation in the management of various malignancies in humans. Evidence regarding their use in the treatment of genitourinary tumours is reviewed here, focusing primarily on clinical data. The majority of available evidence comes from meeting abstracts and only a few published manuscripts were detected. The efficacy of selective COX-2 inhibitors, a subcategory of anti-inflammatory drugs, is promising in prostate cancer, in either biochemical recurrence after initial treatment or advanced disease. This does not seem to be the case for renal tumours in which efficacy in the advanced disease setting is not satisfactory. Despite the well-documented rationale for the application of NSAIDs in bladder cancer management, clinical evidence is not available. More studies are needed to assess the efficacy of anti-inflammatory agents in bladder cancer treatment and further clarify their therapeutic benefit in patients with prostate cancer, in which initial results are encouraging.

Cyclooxygenase in the treatment of glioma: its complex role in signal transduction

BACKGROUND

High-grade glioma remains one of the most difficult cancers to treat. Recent studies in oncology have identified a role of the ubiquitous enzyme, cyclooxygenase (Cox), especially cyclooxygenase-2 (COX-2) in cell proliferation, and its inhibition in cancer control, apoptosis, as well as synergy with other forms of therapy. The inhibitors of the Cox enzyme are well known as members of the nonsteroidal anti-inflammatory drug (NSAID) class of pharmaceuticals.

METHODS

In vitro and in vivo studies of different cancers expressing COX-2, including glioma studies, along with the few clinical trials that have been reported are reviewed to specifically identify the actions of these agents.

RESULTS

The anticancer effect of the COX-2 inhibitors may occur irrelevant of COX-2 expression, and it appears to be drug-specific, as well as dose-specific in different cancers. In combination with chemotherapeutic agents, the COX-2 inhibitors may have an additive, synergistic, or inhibitory effect on tumor growth.

CONCLUSIONS

As evaluations of this class of drugs begin in glioma, in vitro and in vivo data should be acquired to accurately predict which compounds will have an effect in controlling tumor growth and at which doses these should be used. The actual expression and inhibition of COX-2 may not always be relevant to the effects on tumor growth.

Cyclooxygenase-2 (cox-2) and the inflammogenesis of cancer

Cohesive scientific evidence from molecular, animal, and human investigations supports the hypothesis that aberrant induction of COX-2 and up-regulation of the prostaglandin cascade play a significant role in carcinogenesis, and reciprocally, blockade of the process has strong potential for cancer prevention and therapy. Supporting evidence includes the following: [1] expression of constitutive COX-2-catalyzed prostaglandin biosynthesis is induced by most cancer-causing agents including tobacco smoke and its components (polycylic aromatic amines, heterocyclic amines, nitrosamines), essential polyunsaturated fatty acids (unconjugated linoleic acid), mitogens, growth factors, proinflammatory cytokines, microbial agents, tumor promoters, and other epigenetic factors, [2] COX-2 expression is a characteristic feature of all premalignant neoplasms, [3] COX-2 expression is a characteristic feature of all malignant neoplasms, and expression intensifies with stage at detection and cancer progression and metastasis, [4] all essential features of carcinogenesis (mutagenesis, mitogenesis, angiogenesis, reduced apoptosis, metastasis, and immunosuppression) are linked to COX-2-driven prostaglandin (PGE-2) biosynthesis, [5] animal studies show that COX-2 up-regulation (in the absence of genetic mutations) is sufficient to stimulate the transformation of normal cells to invasive cancer and metastatic disease, [6] non-selective COX-2 inhibitors, such as aspirin and ibuprofen, reduce the risk of human cancer and precancerous lesions, and [7] selective COX-2 inhibitors, such as celecoxib, reduce the risk of human cancer and precancerous lesions at all anatomic sites thus far investigated. Results confirming that COX-2 blockade is effective for both cancer prevention and therapy have been tempered by observations that some COX2 inhibitors pose a risk to the cardiovascular system, and more studies are needed in order to determine if certain of these drugs can be taken at dosages that prevent cancer without increasing cardiovascular risk. It is emphasized that the "inflammogenesis model of cancer" is not mutually exclusive and may in fact be synergistic with the accumulation of somatic mutations in tumor suppressor genes and oncogenes or epigenetic factors in the development of cancer.

Cyclo-oxygenase-2 and its inhibition in cancer: is there a role?

Despite recent improvements in chemotherapy and radiation therapy in cancer management with the addition of biological agents, novel treatment approaches are needed to further benefit patients. Cyclo-oxygenase (COX)-2 inhibition represents one such possibility. COX-2 is an enzyme induced in pathological states such as inflammatory disorders and cancer, where it mediates production of prostanoids. The enzyme is commonly expressed in both premalignant lesions and malignant tumours of different types. A growing body of evidence suggests an association of COX-2 with tumour development, aggressive biological tumour behaviour, resistance to standard cancer treatment, and adverse patient outcome. COX-2 may be related to cancer development and propagation through multiple mechanisms, including stimulation of growth, migration, invasiveness, resistance to apoptosis, suppression of the immunosurveillance system, and enhancement of angiogenesis. Epidemiological data suggest that NSAIDs and selective COX-2 inhibitors might prevent the development of cancers, including colorectal, oesophageal and lung cancer. Preclinical investigations have demonstrated that inhibition of this enzyme with selective COX-2 inhibitors enhances tumour response to radiation and chemotherapeutic agents. These preclinical findings have been rapidly advanced to clinical oncology. Clinical trials of the combination of selective COX-2 inhibitors with radiotherapy, chemotherapy or both in patients with a number of cancers have been initiated, and preliminary results are encouraging. This review discusses the role of COX-2, its products (prostaglandins) and its inhibitors in tumour growth and treatment.

Expression of Cox-1 and Cox-2 in Canine Mammary Tumours

The aim of this study was to investigate immunohistochemically the expression of cyclooxygenase-1 (Cox-1) and cyclooxygenase-2 (Cox-2) in canine mammary tumours of different histological types. Cox-1 and Cox-2 enzyme expression was evaluated in 70 mammary samples (four normal, six hyperplastic, 60 neoplastic [21 benign and 39 malignant]). Cox-1 expression was identified in all the samples, and Cox-2 in all the mammary lesions except ductal hyperplasia. Two of the four normal mammary gland samples showed focal immunoreactivity for Cox-2. Cox-1 immunoexpression did not differ significantly between benign and malignant lesions (P=0.272). Cox-2 immunoexpression was higher in malignant tumours than in benign counterparts (P<0.001). Of the malignant tumours, carcinosarcomas and tubulopapillary and squamous cell carcinomas had the highest Cox-2 scores. The study showed that malignant tumours had the highest values of Cox-2 expression, and Cox-2 immunolabelling was particularly intense in histological types classically associated with high malignancy. This suggests that nonsteroidal anti-inflammatory drugs (NSAIDs), particularly Cox-2 inhibitors, may have a useful role to play in the treatment of canine malignant mammary tumours.