Rationale for use of cyclooxygenase-2 inhibitors in prevention and treatment of bladder cancer

Genetic and molecular biology of bladder cancer among Iranian patients

Background

Bladder cancer (BC) is the sixth common cancer among Iranians. Various risk factors such as smoking, body mass index, chronic infection, age, and genetic factors are associated with BC progression.

Methods

It has been shown that a significant ratio of patients have tumors with muscle bladder layer invasion and poor prognosis at the time of diagnosis. Therefore, the early detection of tumors is required to reduce the mortality rate of BC cases. Since there is a wide geographical incidence variation in BC in Iran, it seems that the ethnic and genetic factors can be the main risk factors among Iranian BC patients.

Results

For the first time, in present review we have summarized all of the reported genes among Iranian BC patients until now which were significantly associated with tumorigenesis. Moreover, we categorized all of the reported genes based on their cell and molecular functions to clarify the genetic and molecular biology of BC among Iranian population.

Conclusion

This review paves the way of determination of a population‐based genetic panel markers for the early detection of BC in this population.

Utility of biomarkers in the prediction of oncologic outcome after radical cystectomy for squamous cell carcinoma

PURPOSE

We evaluated the association of multiple biomarkers with clinical outcomes in patients treated with radical cystectomy for squamous cell carcinoma of the bladder to identify the best prognostic panel of markers.

MATERIALS AND METHODS

Immunohistochemistry for 14 biomarkers was performed on tissue microarray sections of 151 radical cystectomy specimens showing squamous cell carcinoma. Biomarker alterations, pathological features and oncologic outcomes were evaluated. The panel of biomarkers that best predicted the oncologic outcome was determined. Outcomes were stratified based on a prognostic score according to the number of altered biomarkers. The accuracy of oncologic outcome prediction was evaluated by ROC curves.

RESULTS

The study included 151 patients. Pathological stage was T2 in 50%, T3 in 38%, T1 in 6% and T4 in 6% of patients. Median followup was 63.2 months. The best prognostic panel of markers included COX-2, FGF-2, p53, Bax and EGFR. On multivariate Cox regression analysis a prognostic score based on marker alterations was an independent predictor of intermediate and high risk of disease recurrence (HR 3.2, p = 0.008 and HR 15.5, p ≤ 0.001) and bladder cancer specific mortality (HR 5.2, p = 0.009 and HR 19.4, p ≤ 0.001, respectively). A multivariate prognostic model incorporating the prognostic score demonstrated significantly better performance to predict the outcome compared to clinicopathological parameters only (0.78 vs 0.64).

CONCLUSIONS

Biomarkers have significant potential to predict the outcome of radical cystectomy for squamous cell carcinoma. An increased number of altered markers may identify patients at high risk who might benefit from multimodal treatment approaches.

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.

Cigarette smoking and subtypes of bladder cancer

There is little information regarding associations between suspected bladder cancer risk factors and tumor subtypes at diagnosis. Some, but not all, studies have found that bladder cancer among smokers is often more invasive than it is among nonsmokers. This population-based case-control study was conducted in Los Angeles, California, involving 1,586 bladder cancer patients and their individually matched controls. Logistic regression was used to conduct separate analyses according to tumor subtypes defined by stage and grade. Cigarette smoking increased risk of both superficial and invasive bladder cancer, but the more advanced the stage, the stronger the effect. The odds ratios associated with regular smokers were 2.2 (95% confidence intervals, 1.8-2.8), 2.7 (2.1-3.6) and 3.7 (2.5-5.5) for low-grade superficial, high-grade superficial and invasive tumors respectively. This pattern was consistently observed regardless of the smoking exposure index under examination. Women had higher risk of invasive bladder cancer than men even they smoked comparable amount of cigarettes as men. There was no gender difference in the association between smoking and risk of low-grade superficial bladder cancer. The heterogeneous effect of cigarette smoking was attenuated among heavy users of NSAIDs. Our results indicate that cigarette smoking was more strongly associated with increased risk of invasive bladder cancer than with low-grade superficial bladder cancer.

Long-term use of supplemental vitamins and minerals does not reduce the risk of urothelial cell carcinoma of the bladder in the VITamins And Lifestyle study

PURPOSE

Urothelial carcinoma has the highest lifetime treatment cost of any cancer, making it an ideal target for preventative therapies. Previous work has suggested that certain vitamin and mineral supplements may reduce the risk of urothelial carcinoma. We used the prospective VITamins And Lifestyle cohort to examine the association of all commonly taken vitamin and mineral supplements as well as 6 common anti-inflammatory supplements with incident urothelial carcinoma in a United States population.

MATERIALS AND METHODS

A total of 77,050 eligible VITAL participants completed a detailed questionnaire at baseline on supplement use and cancer risk factors. After 6 years of followup 330 incident urothelial carcinoma cases in the cohort were identified via linkage to the Seattle-Puget Sound SEER cancer registry. We analyzed use of supplemental vitamins (multivitamins, beta-carotene, retinol, folic acid, and vitamins B1, B3, B6, B12, C, D and E), minerals (calcium, iron, magnesium, zinc and selenium) and anti-inflammatory supplements (glucosamine, chondroitin, saw palmetto, ginkgo biloba, fish oil and garlic). For each supplement the hazard ratios (risk ratios) for urothelial carcinoma comparing each category of users to nonusers, and 95% CIs, were determined using Cox proportional hazards regression, adjusted for potential confounders.

RESULTS

None of the vitamin, mineral or anti-inflammatory supplements was significantly associated with urothelial carcinoma risk in age adjusted or multivariate models.

CONCLUSIONS

The results of this study do not support the use of commonly taken vitamin or mineral supplements or 6 common anti-inflammatory supplements for the chemoprevention of urothelial carcinoma.

Prognostic value of cyclooxygenase-2 expression in squamous cell carcinoma of the bladder

PURPOSE

Inflammation is associated with the pathogenesis of carcinoma, including squamous cell carcinoma of the bladder. Cyclooxygenase-2 is an enzyme that is induced at inflammation sites. We assessed the expression pattern of cyclooxygenase-2 in patients with squamous cell carcinoma of the bladder and determined whether cyclooxygenase-2 expression is associated with clinical outcomes after radical cystectomy.

MATERIALS AND METHODS

Immunohistochemical staining for cyclooxygenase-2 was done on archival bladder specimens from 152 patients treated with radical cystectomy for squamous cell carcinoma on the Autostainer (DakoCytomation, Carpinteria, California). Bright field microscopy imaging coupled with advanced color detection software was used. Cyclooxygenase-2 was defined as over expressed when greater than 20% cells were positive. We assessed the relationship of cyclooxygenase-2 expression with pathological parameters and clinical outcome.

RESULTS

The study included 99 male and 53 female patients with a mean age of 52 years who had squamous cell carcinoma, including 80.9% with bilharziasis. Presenting stage was T2 or greater and presenting grade was GII or less in 93.4% of patients. Median followup was 63.2 months. Cyclooxygenase-2 was over expressed in 74 cystectomy specimens (48.7%) and associated with higher pathological stage (p=0.003) and grade (p=0.049). On multivariate Cox proportional hazards regression analysis cyclooxygenase-2 over expression was associated with disease recurrence (p=0.031) and bladder cancer specific mortality (p=0.046).

CONCLUSIONS

Cyclooxygenase-2 over expression is associated with pathological stage, grade and worse outcomes after radical cystectomy, suggesting a role in bladder squamous cell carcinoma progression. Our findings support the need for further evaluation of cyclooxygenase-2 and inflammatory signaling pathways, and cyclooxygenase-2 targeted prevention or therapy in patients with bladder squamous cell carcinoma.

Bilharzial vs non-bilharzial related bladder cancer: pathological characteristics and value of cyclooxygenase-2 expression

OBJECTIVE

• To assess the expression pattern of cyclooxygenase-2 (COX-2) in bilharzial and non-bilharzial related bladder cancer (BBC and NBBC) and its association with clinical outcome after radical cystectomy (RC). We also determined the clinico-pathological differences between BBC and NBBC.

PATIENTS AND METHODS

• Immunohistochemical (IHC) staining for COX-2 was performed on archival bladder specimens from 315 patients treated with RC between 1997 and 2003. • Patients were divided into 2 groups: Group 1 comprised 205 patients (65%) with BBC and group 2 comprised 110 patients (35%) with NBBC. • Clinico-pathological differences were compared and altered IHC expression of COX-2 was correlated with clinical outcome in both groups.

RESULTS

• The study included 315 patients (239 males and 76 females) with median age 54 y (range 31-79) and median follow up of 63.2 months after RC. • There was significant difference in histological types, tumor stage, grade, and architecture and COX-2 alterations between both groups (P < 0.05). • BBC presented with lower grade, higher stage, and non-papillary non-urothelial carcinoma. COX-2 overexpression was associated with pathological T stage (P= 0.01), grade (P < 0.001) and lymphovascular invasion (LVI) (P= 0.041). • COX-2 expression was an independent predictor of disease recurrence (HR 1.9, CI 0.99-3.626 and P= 0.05) and cancer specific mortality (HR 2.8, CI 1.155-6.73 and P= 0.023) only in BBC but not in NBBC (HR 1.6, CI 0.598-4.364, P= 0.344 and HR 0.349, CI 0.076-1.595, P= 0.175, respectively).

CONCLUSIONS

• BBC differs pathologically and biologically from NBBC. BBCs present more frequently as low-grade, high stage non-papillary and non-urothelial cancers. BBCs with COX-2 alterations are associated with worse outcome after RC. • Our findings support the need for further evaluation of COX-2 and inflammatory signaling pathways as well as COX-2-targeted prevention and therapies in BC.

Urothelial overexpression of insulin-like growth factor-1 increases susceptibility to p-cresidine-induced bladder carcinogenesis in transgenic mice

To establish a role for insulin-like growth factor-1 (IGF-1) in bladder cancer susceptibility, we tested the effect of p-cresidine, a potent bladder carcinogen, in transgenic (TG) mice with human IGF-1 expression in the bladder driven by the bovine keratin 5 promoter (referred to as BK5.IGF-1 TG mice). Indomethacin was also tested to determine if the cyclooxygenase (COX) pathway is a target for bladder cancer prevention in this model. Thirty-three female BK5.IGF-1 TG mice and 29 female nontransgenic littermates were randomized to the following treatments: (1) AIN-76A diet; (2) AIN-76A diet with 0.5% p-cresidine; or (3) AIN-76A diet with 0.5% p-cresidine + 0.00075% indomethacin. BK5.IGF-1 TG mice, with twofold greater total serum IGF-1 than nontransgenic mice, exhibited greatly increased susceptibility to p-cresidine-induced bladder tumors compared to nontransgenic mice. The most common type of bladder tumor in the BK5.IGF-1 TG mice was transitional cell carcinoma, which is the predominant type of bladder cancer observed in developed countries. Indomethacin inhibition of bladder tumor development in BK5.IGF-1 TG mice was not statistically significant. These results present further evidence for the role of IGF-1 in bladder cancer progression. In addition, these transgenic mice provide a useful model for studying the role of the IGF-1 pathway in bladder carcinogenesis and its prevention.

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.

In vitro and in vivo inhibitory effect evaluation of cyclooxygenase-2 inhibitors, antisense cyclooxygenase-2 cDNA, and their combination on the growth of human bladder cancer cells

Overexpression of cyclooxygenase (COX)-2 is associated with the progression of various malignancies, but the contribution of COX-2 expression, bioactivity or their cooperation to bladder cancer growth calls for further clarification. In this study, we investigated the inhibitory effect of COX-2 inhibitors, antisense COX-2 nucleotide, and their combination on the growth of bladder cancer cells (5637, 5637-P and 5637-AS). Suppression of either COX-2 expression or activity caused reduced cell proliferation, enhanced cell numbers in G(1) phase, and increased apoptosis; the joint suppression of COX-2 expression and bioactivity enhanced the degree of cell growth inhibition. COX-2 antisense-expressing 5637-AS tumors showed a 41.42+/-3.08% growth inhibition as compared with 5637 controls. Oral administration of indomethacin (3mg/kg) or celecoxib (15 mg/kg) caused tumor growth inhibition by 31.5+/-14.87% or 83.17+/-1.17%, respectively. When COX-2 antisense cDNA and COX-2 inhibitor celecoxib were combined, the tumor growth inhibition rate was further increased up to 88.78+/-3.10%. These results provide evidence that celecoxib has potential therapeutic effect on bladder cancer, and the joint use of COX-2 antisense cDNA with celecoxib may improve their individual therapeutic effect, especially significantly increase the growth inhibitory effect of COX-2 antisense cDNA.

Cyclooxygenase-2 expression is critical for chronic UV-induced murine skin carcinogenesis

While it has been established that both the constitutive and inducible forms of cyclooxygenase (COX-1 and COX-2, respectively) play important roles in chemical initiation-promotion protocols with phorbol ester tumor promoters, the contribution of these two enzymes to ultraviolet (UV) light-induced skin tumors has not been fully assessed. To better understand the contribution of COX-1 and COX-2 to UV carcinogenesis, we transferred the null allele for each isoform onto the SKH-1 hairless strain of mouse. Due to low viability on this background with complete knockout of COX-2, heterozygous mice were used in UV carcinogenesis experiments. While the lack of one allele of COX-1 had no effect on tumor outcome, the lack of one allele of COX-2 resulted in a 50-65% reduction in tumor multiplicity and a marked decrease in tumor size. Additionally, transgenic SKH-1 mice that overexpress COX-2 under the control of a keratin 14 promoter developed 70% more tumors than wild-type SKH-1 mice. The lack of one allele of either COX-1 or COX-2 reduced prostaglandin (PG) E2 levels in response to a single UV treatment. The proliferative response to UV was significantly reduced in COX-2, but not COX-1, heterozygous mice. UV-induced apoptosis, however, was greater in COX-2 heterozygous mice. Collectively, these results clearly establish the requirement for COX-2 in the development of skin tumors.

Advances in the management of superficial bladder cancer

Given its high tendency to recur, coupled with an ever-present possibility to progress to potentially life-threatening muscle-invasive disease, superficial bladder cancer remains a challenging clinical problem. Optimal management begins with early detection and accurate risk assessment through careful attention to clinical features, aided by an emerging array of urinary markers and molecular characterizations. Prevention of recurrence requires the sequential application of tools to completely remove all visible disease, avert reimplantation during surgical resection, ablate microscopic foci, and prevent the emergence of new primary tumors amidst a field of carcinogen-exposed urothelium. Previously standard adjunctive intravesical chemo- and immunotherapies are enjoying new vitality as optimization strategies, new drugs, and rational drug combinations provide the potential for improved efficacy with reduced toxicity. New technological advances such as fluorescence-aided cystoscopy, microwave chemothermotherapy, and electromotive chemotherapeutic drug delivery offer further hope for better outcomes even for disease previously refractory to conservative measures. Yet despite these advances, aggressive surgical management involving bladder removal continues to be an indispensable life-saving maneuver that must be considered in all high-risk cases that fail to promptly respond to other measures.

Ochratoxin A: An overview on toxicity and carcinogenicity in animals and humans

Ochratoxin A (OTA) is a ubiquitous mycotoxin produced by fungi of improperly stored food products. OTA is nephrotoxic and is suspected of being the main etiological agent responsible for human Balkan endemic nephropathy (BEN) and associated urinary tract tumours. Striking similarities between OTA-induced porcine nephropathy in pigs and BEN in humans are observed. International Agency for Research on Cancer (IARC) has classified OTA as a possible human carcinogen (group 2B). Currently, the mode of carcinogenic action by OTA is unknown. OTA is genotoxic following oxidative metabolism. This activity is thought to play a central role in OTA-mediated carcinogenesis and may be divided into direct (covalent DNA adduction) and indirect (oxidative DNA damage) mechanisms of action. Evidence for a direct mode of genotoxicity has been derived from the sensitive 32P-postlabelling assay. OTA facilitates guanine-specific DNA adducts in vitro and in rat and pig kidney orally dosed, one adduct comigrates with a synthetic carbon (C)-bonded C8-dG OTA adduct standard. In this paper, our current understanding of OTA toxicity and carcinogenicity are reviewed. The available evidence suggests that OTA is a genotoxic carcinogen by induction of oxidative DNA lesions coupled with direct DNA adducts via quinone formation. This mechanism of action should be used to establish acceptable intake levels of OTA from human food sources.

Prevention of prostate cancer through custom tailoring of chemopreventive regimen

One practical way to control cancer is through chemoprevention, which refers to the administration of synthetic or naturally occurring agents to block, reverse or delay the process of carcinogenesis. For a variety of reasons, the most important of which is human acceptance, for chemopreventive intervention naturally occurring diet-based agents are preferred over synthetic agents. For a long time, the prevailing mantra of cancer chemoprevention has been: "Find effective agents with acceptable or no toxicity and use them in preventing cancer in relatively healthy people or individuals at high risk for developing cancer". In pursuing this goal many naturally occurring phytochemicals capable of affording protection against carcinogenesis in preclinical settings in experimental animals have been described. However, clinical trials of single agents have yielded disappointing results. Since carcinogenesis is a multistage phenomenon in which many normal cellular pathways become aberrant, it is unlikely that one agent could prove effective in preventing cancer. This review underscores the need to build an armamentarium of naturally occurring chemopreventive substances that could prevent or slow down the development and progression of prostate cancer. Thus, the new effective approach for cancer prevention "building a customized mechanism-based chemoprevention cocktail of naturally occurring substances" is advocated.

Expression of Cyclooxygenase-2 in Normal Urothelium, and Superficial and Advanced Transitional Cell Carcinoma of Bladder

PURPOSE

We compared the differential expression of cyclooxygenase-2 in normal bladder tissue, primary bladder transitional cell carcinoma and transitional cell carcinoma metastases to lymph nodes, and determined whether cyclooxygenase-2 expression is associated with molecular alterations commonly found in bladder transitional cell carcinoma and clinical outcomes after radical cystectomy.

MATERIALS AND METHODS

Immunohistochemical staining for cyclooxygenase-2, survivin (Novus Biologicals, Littleton, Colorado), p21, p27, pRB, p53, MIB-1, Bax, Bcl-2, cyclin D(1) (Dakotrade mark), cyclin E (Oncogene, Cambridge, Massachusetts) and caspase-3 (Cell Signaling, Beverley, Massachusetts) was performed on archival bladder specimens from 9 subjects who underwent cystectomy for benign causes, 21 patients who underwent transurethral resection and 157 consecutive patients after radical cystectomy, and on 41 positive lymph nodes.

RESULTS

Cyclooxygenase-2 was expressed in none of the 9 normal bladder specimens (0%), 52% of transurethral resection specimens, 62% of cystectomy specimens and 80% of lymph nodes involved with transitional cell carcinoma. Cyclooxygenase-2 expression was associated with higher pathological stage, lymphovascular invasion and metastases to lymph nodes (p=0.001, 0.045 and 0.002, respectively). Cyclooxygenase-2 expression was associated with altered expression of p53 (p=0.039), pRB (p=0.025), cyclin D1 (p=0.034) and caspase-3 (p=0.014). On univariate analysis cyclooxygenase-2 expression was associated with an increased risk of disease recurrence and bladder cancer specific mortality (p=0.0189 and 0.0472, respectively). However, on multivariate analysis only pathological stage and metastases to lymph nodes were associated with disease recurrence (p<0.001 and <0.001) and survival (p<0.001 and 0.015, respectively).

CONCLUSIONS

Cyclooxygenase-2 is not expressed in normal bladder urothelium. Cyclooxygenase-2 over expression is associated with pathological and molecular features of biologically aggressive disease, suggesting a role for cyclooxygenase-2 in bladder cancer development and invasion.

Early bladder cancer: concept, diagnosis, and management

Recent evidence on molecular pathways helps us to understand the pathogenesis of bladder cancer. However, the molecular mechanisms of recurrence of the disease and progression into muscle-invasive disease are not fully understood. The diagnostic accuracy and specificity of innovative markers for detection of the disease currently available in the clinical setting are still far from the level where cystoscopy would not be needed. Although risk factors for progression to muscle-invasive disease have been identified, we still cannot predict accurately the clinical behavior of superficial bladder cancer. In this review article, we summarize recent evidence on molecular pathogenesis, risk factors for recurrence and progression, urine markers for detection, and treatments in superficial bladder cancer.