Effect of indomethacin on N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide-induced urinary tract carcinogenesis

Cyclooxygenase-2 and Survivin in Superficial Urothelial Carcinoma of the Bladder and Correlation with Intratumoural Microvessel Density

This study was designed to investigate the protein levels of cyclooxyogenase-2 (COX-2) and survivin in superficial urothelial carcinoma (UC) and their correlation with microvessel density (MVD). High-grade UC was positive for both COX-2 and survivin protein, and the proportion of tumours positive for both proteins increased with increasing tumour grade. The presence of COX-2 protein was significantly correlated with the presence of survivin protein. Both COX-2 and survivin positivity were significantly correlated with MVD in all patients regardless of tumour grade, but there was no correlation between MVD and COX-2 and survivin positivity by individual tumour grade. Although there was no significant difference in the proportion of COX-2-positive tumours when patients were stratified by tumour stage, a significantly higher proportion of patients with pT1 stage tumours were survivin-positive compared with patients with pTa stage tumours. COX-2 and survivin positivity were significantly correlated in all patients regardless of tumour grade or stage. COX-2 and survivin were significantly correlated in patients with pTa, but there was no correlation in pT1 tumours. These findings demonstrate that together, COX-2, survivin and MVD may play an important role in UC.

Possible Contribution of Indomethacin to the Carcinogenicity of Nongenotoxic Bladder Carcinogens That Cause Bladder Calculi

Nongenotoxic bladder carcinogens that form bladder calculi have been concluded to be of low carcinogenic risk to humans because bladder stones would be expelled or surgically removed before they had a chance to exert their carcinogenic effect. It is the aim of this report to examine the possible contribution of indomethacin to the carcinogenic risk posed by nongenotoxic bladder carcinogens that cause bladder stones. Indomethacin may act as a tumor promoter in the bladder by interfering with the synthesis of prostaglandins. Prostaglandins have a cytoprotective function in the gastric mucosa and possibly also in the urinary bladder. Diminished cytoprotection may be implicated in bladder carcinogenesis as beta-naphthylamine, a human bladder carcinogen, also inhibits prostaglandin synthesis in vitro. The presence of other tumor promoters in the bladder may further ensure that tumors would be formed even if bladder stones were expelled. People who are exposed to nongenotoxic bladder carcinogens that are present in the environment and that form bladder stones, therefore, may be at an increased risk for developing bladder cancer if they are also exposed to tumor promoters, such as indomethacin.

COX-2 inhibitors and other nonsteroidal anti-inflammatory drugs in genitourinary cancer

Selective cyclooxygenase (COX)-2-inhibiting and other nonsteroidal anti-inflammatory drugs (NSAIDs) show promise for preventing and treating bladder and prostate cancers. In contrast to the strong NSAID epidemiology in colorectal cancer, the epidemiologic data on NSAIDs and genitourinary (GU) cancers are limited and mixed. However, a substantial body of preclinical in vitro and in vivo animal model data shows consistent NSAID activity in treating, and in some cases preventing, GU cancers and begins to address the mechanisms behind this activity (eg, involving Akt and ERK2 in the prostate). Many preclinical and clinical NSAID studies currently under way are helping to resolve the best type (selective or nonselective COX inhibitors or non-COX inhibitors), dose and duration of NSAID treatment for prevention in the GU setting. Future studies likely will focus on clarifying the NSAID mechanisms behind and developing NSAID combinations for both treating and preventing GU cancers.

Prostaglandin E2 production and cyclooxygenase-2 induction in human urinary tract infections and bladder cancer

PURPOSE

Increased prostaglandin production correlates positively with cancer risk and cyclooxygenase (COX)-2, the inducible rate limiting enzyme for prostaglandin synthesis, is elevated in bladder cancer cases. Urinary prostaglandin levels and COX-2 expression in urine particulates may increase in urogenital cancer, including bladder cancer, and with infectious and inflammatory processes, including urinary tract infections and that resulting from bacillus Calmette-Guerin (BCG) treatment for bladder cancer.

MATERIALS AND METHODS

Urinary prostaglandin E2 levels were measured in patients with a urinary tract infection before and after treatment, urogenital cancer (including bladder cancer), bladder cancer in remission and bladder cancer with BCG treatment. COX-1 and COX-2 mRNA and protein were assessed in the human ureter, in normal human bladder muscle and urothelium, and in urine particulates from patients with urinary tract infections, bladder cancer and bladder cancer with BCG treatment.

RESULTS

COX-1 protein, and mRNA and COX-2 mRNA were expressed in the ureter, and bladder muscle and urothelium. Urinary prostaglandin E2 levels and COX-2 protein expression in urine particulates were elevated in patients with urinary tract infections and with bladder cancer compared with age matched controls. Successful treatment for urinary tract infections and bladder cancer lowers urinary prostaglandin E2 levels. Urinary prostaglandin E2 and COX-2 protein levels are elevated during BCG treatment.

CONCLUSIONS

Increased urinary prostaglandin E2 production and COX-2 protein expression correlate with urogenital cancer, urinary tract infections and inflammatory processes, such as those induced by BCG. Patients in whom urinary tract infection was treated with antibiotics or in whom bladder cancer is in remission have reduced urinary prostaglandin E2 compared with those who have active disease.

Breyer M. Enhanced expression of cyclooxygenase-2 in high grade human transitional cell bladder carcinomas

Studies in human and animal models have shown that cyclooxygenase (COX)-2 is up-regulated in several epithelial carcinomas including colon, breast, and lung. To elucidate the possible involvement of COX-2 in human bladder cancer we examined the expression of COX isoforms in benign tissue and in bladder carcinoma specimens. Paraffin embedded tissues from 75 patients with urothelial carcinomas were immunostained with specific antibodies raised against COX-1 and COX-2. COX-1 expression was detected in smooth muscle cells in both benign and malignant bladders. COX-2 immunoreactivity was absent in benign tissue and in specimens with low-grade urothelial carcinoma (0/23). In contrast, expression of COX-2 was detected in malignant epithelial cells in 38% (17/47) of specimens with high-grade urothelial carcinomas. Expression of COX-2 in high-grade bladder cancer was confirmed by radioactive in situ hybridization using a COX-2-selective riboprobe. Both immunohistochemistry and in situ hybridization showed COX-2 expression in a small subset of malignant cells. COX-2 mRNA was also expressed in three out of seven malignant urothelial cell lines. These data demonstrate elevated expression of COX-2 in a high percentage of high-grade bladder carcinomas, suggesting a possible role of COX-2 in the progression of bladder urothelial carcinoma and supporting its potential as a therapeutic target in human bladder carcinoma.

Effect of indomethacin on tumorigenicity and immunity induction in a murine model of mammary carcinoma

Indomethacin, an inhibitor of cyclo-oxygenase given orally, reduced the tumorigenicity of cancer cells in a non-immunogenic murine model of mammary adenocarcinoma (4T1). In the presence of indomethacin, a dose-dependent immune protection could be induced most effectively by immunizing mice with 1 to 3 doses of irradiated tumor cells inoculated at intervals of 7 days prior to challenge with a tumorigenic cell dose. Three immunizations given without indomethacin resulted in tumor growth in 88% of the recipients, and indomethacin treatment started 28 days prior to the challenge dose and given without immunizations led to tumor onset in 83% of mice. In contrast, tumor was documented only in 12% of mice vaccinated with 3 immunization doses and given concomitantly indomethacin. Moreover, 53% of disease-free survivors resisted a second challenge with a high tumorigenic dose. Induction of an anti-tumor immunity in indomethacin-treated mice was further studied as a therapy for tumor-bearing mice. Complete cure was induced in 50% of mice, and a significant reduction in tumor size as well as prolonged survival time were observed in the remaining animals. Immunostimulation by tumor cell vaccination given in the presence of a tolerable dose of indomethacin, therefore, may be incorporated into immunotherapy protocols to activate an anti-tumor response against residual tumor cells that escaped surgery and/or high-dose chemo/radiotherapy.

Chemopreventive efficacy of piroxicam administered alone or in combination with lycopene and beta-carotene on the development of rat urinary bladder carcinoma after N-butyl-N-(4-hydroxybutyl)nitrosamine treatment

The effects of the non-steroidal anti-inflammatory drug (NSAID) piroxicam and the carotenoids lycopene and beta-carotene, alone or in combination, on the development of rat superficial urinary bladder carcinomas induced by N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) were studied. Male Fischer 344 rats, 6 weeks old, were given 0.05% BBN in the drinking water for 8 weeks followed by administration of piroxicam (0.0075% in the diet), lycopene (0.0025% in the drinking water) and/or beta-carotene (0.0025% in the drinking water) for 12 weeks, then killed for histological analysis of urinary bladder lesions. Cell proliferation potential was analyzed by immunohistochemical staining of the proliferative cell nuclear antigen (PCNA). Piroxicam alone, piroxicam+lycopene, and piroxicam +lycopene+ beta-carotene all significantly decreased the incidences and numbers of transitional cell carcinomas (TCCs), but the combination of piroxicam with carotenoids did not result in a clear improvement in the preventive potential of piroxicam. Piroxicam+ beta-carotene also caused a significant reduction and lycopene alone a slight but not significant reduction in the number of TCCs. In contrast, beta-carotene alone and lycopene+ beta-carotene were without inhibitory influence on any of the lesion categories examined, and the latter significantly increased the proportion of high-grade TCCs. Nevertheless, all of the chemopreventive agents, either alone or in combination, significantly decreased the TCC PCNA index, the effect extending to the surrounding epithelium in the piroxicam+lycopene and piroxicam+lycopene+beta-carotene groups. These results indicate that the NSAID piroxicam may be a more effective chemopreventive agent than lycopene and beta-carotene for superficial urinary bladder carcinogenesis.