Model Of Urinary Bladder Cancer Research Articles

Implementation of Humane Endpoints in a Urinary Bladder Carcinogenesis Study in Rats.

This study aimed to evaluate the utility of several biological parameters for the prediction of tumor development and animal welfare in a rat model of urinary bladder cancer. The control group (n=9) received tap water while the test group (n=12) received the carcinogen N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) in drinking water. A score sheet with biological variables was used to monitor animals' welfare. Body weight, food and drink consumption and rectal temperature were measured weekly. Blood and urine samples were collected. Animals from the control group exhibited a slightly higher body weight and body weight gain. The final urine volume was higher in BBN group (p<0.05). All animals from the BBN group exhibited macroscopic hematuria at 35th week. Four animals were anemic in the last week of the experiment. The routine control of hematuria was a useful non-invasive biomarker of disease progression that may be used as a potential earlier humane endpoint. Animals did not show clinical signs of suffering that justified their sacrifice before the end of the study.

The Antineoplastic Activity of Photothermal Ablative Therapy with Targeted Gold Nanorods in an Orthotopic Urinary Bladder Cancer Model.

Background:Gold nanoparticles treated with near infrared (NIR) light can be heated preferentially, allowing for thermal ablation of targeted cells. The use of novel intravesical nanoparticle-directed therapy in conjunction with laser irradiation via a fiber optic cystoscope, represents a potential ablative treatment approach in patients with superficial bladder cancer.Objective:To examine the thermal ablative effect of epidermal growth factor receptor (EGFR)-directed gold nanorods irradiated with NIR light in an orthotopic urinary bladder cancer model.Methods:Gold nanorods linked to an anti-EGFR antibody (Conjugated gold NanoRods – CNR) were instilled into the bladder cavity of an orthotopic murine xenograft model with T24 bladder cancer cells expressing luciferase. NIR light was externally administered via an 808 nm diode laser. This treatment was repeated weekly for 4 weeks. The anti-cancer effect was monitored by an in vivo imaging system in a non-invasive manner, which was the primary outcome of our study.Results:The optimal approach for an individual treatment was 2.1 W/cm2 laser power for 30 seconds. Using this in vivo model, NIR light combined with CNR demonstrated a statistically significant reduction in tumor-associated bioluminescent activity (n = 16) compared to mice treated with laser alone (n = 14) at the end of the study (p = 0.035). Furthermore, the CNR+NIR light treatment significantly abrogated bioluminescence signals over a 6-week observation period, compared to pre-treatment levels (p = 0.045).Conclusions:Photothermal tumor ablation with EGFR-directed gold nanorods and NIR light proved effective and well tolerated in a murine in vivo model of urinary bladder cancer.

Abstract PR09: Intermittent dosing regimens maintain efficacy of several cancer preventing drugs

Abstract Many potential chemopreventive drugs have adverse effects on human subjects when given daily. One strategy to alleviate these adverse events is to give the drugs on an intermittent dosing schedule. Such intermittent dosing has proven effective in other settings to reduce toxicity with limited effect on efficacy. Two animal models were used: the rat methylnitrosourea (MNU) - induced mammary cancer model and the rat hydroxy-butyl(butyl)-nitrosamine (OH-BBN) -induced urinary bladder cancer model. For the mammary study female Sprague-Dawley rats were given 75 mg of MNU/kg body weight at 50 days of age and five days later the EGFR inhibitors, Erlotinib, Gefitinib or Lapatinib were administered either daily or once a week at two dose levels. Multiplicity of ER-positive mammary cancers was followed weekly for four months. For the urinary bladder study female Fischer 344 rats were given 150 mg OH-BBN/gavage twice weekly beginning at 56 days of age and continuing for 8 weeks. Two weeks after the last OH-BBN treatment the rats were given naproxen either daily, one week on/one week off, or 3 weeks on/3 weeks off. Bladders were excised after 8 months of naproxen treatment and bladders with tumors were excised and weighed. EGFR inhibitors and the NSAID, Naproxen, have similar efficacy when given intermittently compared to daily. The EGFR antagonists, Erlotinib and Lapatinib, decreased mammary cancer multiplicity by 90% given daily and 75 % given weekly. The NSAID, naproxen, decreased large bladder cancers by about 65-80% given either daily, one week on/one week off or 3 weeks on/3 weeks off. Therefore intermittent dosing can be used for agents in two different mechanistic classes in animal mammary and bladder cancer models to lower toxicity, yet show little reduction in chemoprevention efficacy compared to daily dosing. Intermittent dosing schedules in the clinic should reduce EGFR mediated rash and NSAID induced gastric toxicity clinically while retaining efficacy. Citation Format: Vernon E. Steele, Clinton J. Grubbs, Ronald A. Lubet. Intermittent dosing regimens maintain efficacy of several cancer preventing drugs. [abstract]. In: Proceedings of the Thirteenth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2014 Sep 27-Oct 1; New Orleans, LA. Philadelphia (PA): AACR; Can Prev Res 2015;8(10 Suppl): Abstract nr PR09.

Abstract 2728: Thermal ablative therapy with novel gold nanorods in an orthotopic model of urinary bladder cancer

Abstract Background The use of nanoparticles has shown great therapeutic potential, but delivery and clearance concerns have limited their use systemically. Intravesical instillation of nanoparticles in the urinary bladder provides a unique administration route to treat superficial bladder cancer. We examined the anti-tumor effect of epidermal growth factor receptor (EGFR)-directed gold nanorods combined with photothermal treatment in a superficial bladder cancer model. Methods A novel orthotopic nu/nu murine xenograft model was established through intravesical instillation of T24 human bladder cancer cells labeled with Luciferase. After confirmation of positive tumor cell implantation via bioluminescence, gold nanorods linked to the anti-EGFR antibody C225 were instilled into the bladder cavity. The nanorods were specifically fashioned to respond to near infrared (NIR) light, which was externally administered via an 808 nm diode laser to the bladder. A safe and effective regimen of in vivo photothermal ablation was determined by optimizing the duration, power and distance from the tumor to the laser source. The anti-cancer effect was monitored by an in vivo imaging system in a non-invasive manner. Results The tumor implantation rate with the T24 human cancer cell was approximately 90%. The optimized regimen of photothermal treatment in this setting was laser power of 2.1 W/cm2 for 30 seconds at 2.5 centimeters from the skin. Using this in vivo tumor model, and near-infrared energy combined with C225-conjugated gold nanorods, we demonstrate significant therapeutic efficacy against the implanted orthotopic bladder tumor (Table) with minimal systemic toxicity using this regimen. Conclusions Photothermal ablation with EGFR-directed gold nanorods is effective and well tolerated in an in vivo model of urinary bladder cancer. Future clinical development would include NIR light delivery via a cystoscope in a human application Summary of luciferase results of in vivo photothermal treatmentTotal miceLuciferase DecreaseLuciferase IncreaseLuciferase No Significant ChangeConjugated Nano Rods+Laser161303Laser Only14275 Citation Format: Xiaoping Yang, Lih-Jen Su, Francisco G. La Rosa, Elizabeth Erin Smith, Suehyun Katherine Cho, Brian Kavanagh, Won Park, Thomas W. Flaig. Thermal ablative therapy with novel gold nanorods in an orthotopic model of urinary bladder cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2728. doi:10.1158/1538-7445.AM2014-2728

Regulator of G protein Signaling 6 suppresses Ras and DNA‐methyltransferase 1 expression and tumorigenesis in a mouse model of urinary bladder cancer (609.10)

Urinary bladder cancer, the fifth most common cancer in the U.S., frequently results from exposure to toxic chemicals including those present in cigarette smoke. A previous epidemiological study demonstrated that a polymorphism in RGS6 leading to increased translation/stability of RGS6 mRNA was associated with a pronounced reduction in the risk of bladder cancer, particularly in smokers. However, no studies have evaluated whether RGS6 functions as a tumor suppressor in bladder. Here, we employed RGS6‐/‐ mice to investigate the role of RGS6 in BBN (N‐butyl‐N‐(4‐hydroxybutyl) nitrosamine)‐induced bladder cancer, a model which matches well to its human counterpart. We found that RGS6 was highly enriched in mouse bladder, particularly in urothelium where transitional cell carcinoma originates. RGS6 loss was associated with increases in Ras and Dnmt1 expression in the bladder urothelium and marked decreases in Ras‐association domain family 1 isoform A (RASSF1A), a tumor suppressor and target of Dnmt1‐mediated silencing. A similar phenomenon was observed in BBN‐treated WT mice, an effect further exacerbated by BBN treatment of RGS6‐/‐ mice. In keeping with these observations, RGS6‐/‐ mice exhibited accelerated bladder tumor formation. Our findings suggest that RGS6 is a previously unrecognized, but critical repressor for bladder carcinogenesis.Grant Funding Source: Supported by NIH CA161882, AHA 11SDG7580008

Preventive Effects of NSAIDs, NO-NSAIDs, and NSAIDs Plus Difluoromethylornithine in a Chemically Induced Urinary Bladder Cancer Model

Urinary bladder cancer prevention studies were performed with the nonsteroidal anti-inflammatory drugs (NSAID) naproxen (a standard NSAID with a good cardiovascular profile), sulindac, and their nitric oxide (NO) derivatives. In addition, the effects of the ornithine decarboxylase inhibitor, difluoromethylornithine (DFMO), alone or combined with a suboptimal dose of naproxen or sulindac was examined. Agents were evaluated at their human equivalent doses (HED), as well as at lower doses. In the hydroxybutyl(butyl)nitrosamine (OH-BBN) model of urinary bladder cancer, naproxen (400 or 75 ppm) and sulindac (400 ppm) reduced the incidence of large bladder cancers by 82%, 68%, and 44%, respectively, when the agents were initially given 3 months after the final dose of the carcinogen; microscopic cancers already existed. NO-naproxen was highly effective, whereas NO-sulindac was inactive. To further compare naproxen and NO-naproxen, we examined their effects on gene expression in rat livers following a 7-day exposure. Limited, but similar, gene expression changes in the liver were induced by both agents, implying that the primary effects of both are mediated by the parent NSAID. When agents were initiated 2 weeks after the last administration of OH-BBN, DFMO at 1,000 ppm had limited activity, a low dose of naproxen (75 ppm) and sulindac (150 ppm) were highly and marginally effective. Combining DFMO with suboptimal doses of naproxen had minimal effects, whereas the combination of DMFO and sulindac was more active than either agent alone. Thus, naproxen and NO-naproxen were highly effective, whereas sulindac was moderately effective in the OH-BBN model at their HEDs.

Abstract 2273: Metformin promotes tumorigenesis in animal models of cancer prevention.

Abstract Metformin is a bi-guanidine employed in treating Type II diabetes. Epidemiologic studies have suggested that diabetics receiving metformin vs thialidizones or insulin have a lower incidence of cancer. In addition, metformin decreases levels of AMPK and IGF1; encouraging its use in both cancer prevention and therapy settings. Most preclinical studies with metformin have employed cell culture or xenografts. We examined its efficacy in multiple in situ animal cancer models. The preventive effect of Metformin administered by gavage or in the diet, at roughly the human equivalent dose (HED), was determined in four standard animal models: (1) methylnitrosourea (MNU)-induced ER+ mammary cancers; (2) MMTV-Neu ER− mammary cancers; (3) hydroxybutyl(butyl)nitrosamine (OH-BBN) induced urinary bladder cancers; and (4) Min mouse model of intestinal tumorigenesis. In the MNU model, Metformin (150 or 50 mg/Kg BW/day) was ineffective as a preventive dose; decreasing neither tumor multiplicity nor latency. Furthermore, both doses increased final tumor weights in treated rats. PK studies at the higher dose of Metformin (150 mg/kg BW/day) showed serum levels slightly higher than humans taking 1.5 g per day. In the MMTV-Neu model, dietary metformin (1200 PPM in diet) decreased the latency of tumor development as well as slightly, but insignificantly, increasing the final tumor multiplicity. Metformin (1200 ppm in diet) in the Min mouse model marginally increased the multiplicity of intestinal adenomas. In contrast, the NSAID naproxen (400 ppm in diet) examined simultaneously in the min mouse strongly inhibited adenoma development. Metformin (150 mg/Kg BW/day) in the OH-BBN induced model of urinary bladder cancer failed to significantly reduce bladder cancers despite relatively high levels of Metformin in the urine. In the MNU model, when rats were placed on a high fat diet to induce a pre-diabetic state, we observed roughly a 20% decrease in tumor multiplicity in the metformin treated rats (P&amp;gt; 0.10). In contrast, tamoxifen and Targretin (an RXR agonist) that were used as positive controls were highly effective in rats on a high fat diet. Metformin didn't decrease tumorigenesis in these standard models, but actually increased tumor formation (incidence, multiplicity, weight) in three of the four models at their HED. These results should particularly discourage any large phase clinical trials in individuals without insulin resistance. The final study certainly raises the question whether the agent might be effective in animals that are diabetic or show insulin resistance Citation Format: Clinton J. Grubbs, Margie L. Clapper, Joel M. Reid, Vernon E. Steele, Ronald A. Lubet. Metformin promotes tumorigenesis in animal models of cancer prevention. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2273. doi:10.1158/1538-7445.AM2013-2273

Abstract A80: Modified dosing schedules with the EGFr inhibitors gefitinib and lapatinib in rodent models of mammary and urinary bladder cancer: Preventive and therapeutic effects.

Abstract The EGFR inhibitors are approved for treatment of lung and pancreatic cancers (Erlotinib, Gefitinib) and Neu overexpressing breast cancer (Lapatinib) in humans; as well as preventing multiple cancers in animal models. However, the development of toxicities (Iressa, skin rashes; Lapatinib, diarrhea) limit their potential use in prevention; and perhaps even in an adjuvant setting. We examined whether alternative dosing regimens which might reduce toxicity would still achieve preventive and therapeutic efficacy. Female Sprague-Dawley rats were administered a single IV dose of methylnitrosourea (MNU) at 50 days of age. In a prevention study, MNU treated rats administered Gefitinib daily (10 mg/kg BW/day, 7×/week) or Gefitinib (70 mg/kg BW, 1×/week) beginning 5 days after MNU resulted in 94 and 75% reductions, respectively, in cancer multiplicity. Simultaneous measurements of tumor load (number of tumors × tumor weight) showed that both regimens resulted in greater than a 90% decrease. In the therapeutic study (initiating treatment when animals developed a small palpable cancer), both regimens were again highly effective. A prevention study was also performed with Lapatinib (75 mg/kg BW/day, 7×/week or 525 mg/kg BW, 1×/week). While the daily dose reduced cancer multiplicity 90%, the weekly dose caused a 70% reduction. Finally, we examined the effects of daily or weekly dosing with Iressa (100 mg/kg BW/day, 5×/week or 500 or 250 mg/kg BW, 1×/week) in an ER− mouse model (using MMTV/Neu; p53+/− mice). This study showed that while daily dosing with Iressa decreased tumor multiplicity approximately 80%, weekly dosing at either dose caused roughly a 50% decrease. These data show that even a significant alteration in the dosing of Gefitinib (EGFR 1) or Lapatinib (EGFR 2/1) still resulted in a large reduction in mammary cancers. We similarly tested Lapatinib (weekly, 525 mg; or daily, 75 mg/kg/day) in a delayed preventive/therapeutic setting in an OH-BBN model of urinary bladder cancer. We found that although daily dosing was most effective weekly dosing was still relatively effective. The important clinical question will be whether this altered dosing will diminish the toxicities associated with these agents. We cannot determine this in animal models since, at the effective doses employed, the typical toxicities observed in humans are not observed. Supported by NCI contract number HHSN261200433001C. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A80.

Identification of Gene Expression Signature Modulated by Nicotinamide in a Mouse Bladder Cancer Model

BackgroundUrinary bladder cancer is often a result of exposure to chemical carcinogens such as cigarette smoking. Because of histological similarity, chemically-induced rodent cancer model was largely used for human bladder cancer studies. Previous investigations have suggested that nicotinamide, water-soluble vitamin B3, may play a key role in cancer prevention through its activities in cellular repair. However, to date, evidence towards identifying the genetic alterations of nicotinamide in cancer prevention has not been provided. Here, we search for the molecular signatures of cancer prevention by nicotinamide using a N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN)-induced urinary bladder cancer model in mice.Methodology/Principal FindingsVia microarray gene expression profiling of 20 mice and 233 human bladder samples, we performed various statistical analyses and immunohistochemical staining for validation. The expression patterns of 893 genes associated with nicotinamide activity in cancer prevention were identified by microarray data analysis. Gene network analyses of these 893 genes revealed that the Myc and its associated genes may be the most important regulator of bladder cancer prevention, and the gene expression signature correlated well with protein expression data. Comparison of gene expression between human and mouse revealed that BBN-induced mouse bladder cancers exhibited gene expression profiles that were more similar to those of invasive human bladder cancers than to those of non-invasive human bladder cancers.Conclusions/SignificanceThis study demonstrates that nicotinamide plays an important role as a chemo-preventive and therapeutic agent in bladder cancer through the regulation of the Myc oncogenic signature. Nicotinamide may represent a promising therapeutic modality in patients with muscle-invasive bladder cancer.

Abstract 1849: Chemopreventive efficacy of naproxen, sulindac, and their nitric oxide-derivatives in the hydroxylbutyl(butyl)nitrosamine induced model of urinary bladder cancer

Abstract A variety of studies were performed with naproxen (a standard NSAID with a good cardiovascular profile), sulindac, and their nitric oxide (NO)-derivatives. In Fisher 344 rats, OH-BBN (2x/week for 8 weeks by gavage) induced invasive urinary bladder cancers. When treatment was initiated one week following the final dose of OH-BBN, both naproxen (400 ppm) and sulindac (400 ppm) were highly effective preventive agents at these human equivalent doses. The NO-derivatives of each compound (NO-naproxen, 550 ppm and NO-sulindac, 520 ppm) were similarly effective. When the dose of naproxen was decreased from 400 ppm to 75 ppm a strong preventive effect was still observed. This activity was observed even when treatment with naproxen was started 12 weeks after the last OH-BBN treatment; microcarcinomas already existed at this time. In an attempt to make a more direct comparison between the human and rat data, animals were treated with 40 mg/kg BW/day of naproxen by gavage. Similar to the dietary dose of 400 ppm, the agent was highly effective; however, gavaging the rats permitted more direct comparison of the pharmacokinetics observed in the rat with known results in humans. In contrast to the naproxen data, reducing the dose of sulindac from 400 to 150 ppm, a dose comparable to the human dose employed by Meyskens, et al. (Cancer Prevention Res. 1:32-38, 2008), resulted in only limited activity. Finally, the effects of naproxen and NO-naproxen on modulation of gene expression in the livers of treated rats were determined. Limited, but similar, gene expression changes induced by both agents were observed. Interestingly, neither agent induced the antioxidant response element genes [e.g., GST Pi, quinone oxidoreductase, aldo keto reductase A37 (aflatoxicol)] that one might have expected to be highly induced by free NO. Supported by the NCI contract number HHSN261200433001C. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1849. doi:10.1158/1538-7445.AM2011-1849

Abstract 962: Similar preventive effects of naproxen and NO-naproxen in a chemically-induced model of urinary bladder cancer: Dose dependency, gene expression and toxicity

Abstract Non-steroidal anti-inflammatory drugs (NSAIDs) have been highly effective in preventing colon, urinary bladder, and skin cancers preclinically; and also in clinical trials of colon adenoma formation. However, certain NSAIDs cause gastrointestinal (GI) ulceration and may increase cardiovascular (CV) events. Naproxen appears to cause the lowest CV events of the common NSAIDs other than aspirin. NO-naproxen was tested based on the finding that adding a nitric oxide (NO) group to NSAIDs may help alleviate GI toxicity, as well as the expectation that the production of NO itself might be therapeutically effective. We examined these agents in the hydroxybutyl(butyl)nitrosamine (OH-BBN) rat urinary bladder cancer model beginning 2 weeks after the last dose of carcinogen. Naproxen at doses of 400, 200, 128 or 75 ppm in the diet greatly decreased the development of large urinary bladder cancers. NO-naproxen at 183 or 550 ppm caused striking decreases in the incidence of large tumors implying that both agents are similarly effective. The lower doses of these agents are well below the human equivalent dose based on standard scaling factors. We are presently treating rats with naproxen by gavage and collecting serum to directly compare the pharmacokinetics of naproxen in the rat and human. To determine whether there was any indication of NO release in NO-naproxen treated rats, microarrays were performed with liver and bladder tissues from treated rats. Minimal differences in gene expression changes between the two agents were observed. Also, an ARE related response in the liver, which one would have expected from NO, was not seen. Thus, the data are compatible with limited direct effects of NO on urinary bladder cancer prevention. Supported by the NCI contract number HHSN261200433001C. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 962.

Abstract A94: Preventive effects of naproxen and NO-naproxen in carcinogen induced models of urinary bladder, colon, and mammary cancers

Abstract Nonsteroidal anti-inflammatory drugs (NSAIDs) have been highly effective in preventing colon, urinary bladder, and skin cancer preclinically; and also in clinical trials of colon adenoma formation. However, certain NSAIDs cause gastrointestinal (GI) ulceration and may increase cardiovascular (CV) events. Naproxen appears to cause the lowest CV events of the common NSAIDs other than aspirin. NO-naproxen was tested based on the finding that adding a nitric oxide (NO) group to NSAIDs may help alleviate GI toxicity as well as the expectation that the production of NO itself might be therapeutically effective. When examined in the hydroxybutyl(butyl)nitrosamine (OH-BBN) rat urinary bladder cancer model, naproxen at doses of either 400 or 200 ppm in the diet greatly decreased the development of large invasive bladder cancers when treatment was initiated shortly after the last OH-BBN dosing. In a second study, naproxen at 133 ppm or NO-naproxen at 183 or 550 ppm caused striking decreases in the incidence of large tumors. Surprisingly, if treatments were started three months after the last OH-BBN (when multiple microscopic lesions already exist) both NO-naproxen (550 ppm) and naproxen (400 ppm) were still highly effective (91–96% decreases); implying that most of their effects are late. In the azoxymethane (AOM)-induced rat colon aberrant crypt foci (ACF) model, naproxen administered at 200 and 400 ppm reduced mean ACFs in the colon by approximatley 45–60%. NO-naproxen administered at roughly equimolar doses (300 and 600 ppm), reduced total ACF by 20–40%, respectively. In contrast, in the methylnitrosourea (MNU)-induced ER+ mammary cancer model in rats (where most NSAIDs are relatively ineffective) neither NO-naproxen nor naproxen showed significant inhibition at doses of 550 and 400 ppm. These data show that both naproxen and NO-naproxen are effective agents against urinary bladder and colon (but not mammary) carcinogenesis. Additional data showing the effects of sulindac and NO-sulindac in the urinary bladder model will also be presented. Data also imply that both naproxen and NO-naproxen are effective, but that the NO-derivative does not appear to be more effective. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):A94.

Chemopreventive efficacy of naproxen and nitric oxide-naproxen in rodent models of colon, urinary bladder, and mammary cancers.

Nonsteroidal anti-inflammatory drugs (NSAID) have been highly effective in preventing colon, urinary bladder, and skin cancer preclinically, and also in clinical trials of colon adenoma formation. However, certain NSAIDs cause gastrointestinal ulceration and may increase cardiovascular events. Naproxen seems to cause the lowest cardiovascular events of the common NSAIDs other than aspirin. Nitric oxide (NO)-naproxen was tested based on the finding that adding a NO group to NSAIDs may help alleviate GI toxicity. In the azoxymethane-induced rat colon aberrant crypt foci (ACF) model, naproxen administered at 200 and 400 ppm in the diet reduced mean ACFs in the colon by about 45% to 60%, respectively. NO-naproxen was likewise administered in the diet at roughly equimolar doses (300 and 600 ppm) and reduced total ACF by 20% to 40%, respectively. In the hydroxybutyl (butyl) nitrosamine rat urinary bladder cancer model, NO-naproxen was given at 183 or 550 ppm in the diet, and naproxen at 128 ppm. The NO-naproxen groups had 77% and 73% decreases, respectively, in the development of large urinary bladder tumors, whereas the 128 ppm naproxen group also showed a strong decrease (69%). If treatments were started 3 months after hydroxybutyl (butyl) nitrosamine, NO-naproxen (550 ppm) and naproxen (400 ppm) were also highly effective (86-94% decreases). In the methylnitrosourea-induced mammary cancer model in rats, NO-naproxen and naproxen showed nonsignificant inhibitions (12% and 24%) at 550 and 400 ppm, respectively. These data show that both naproxen and NO-naproxen are effective agents against urinary bladder and colon, but not mammary, carcinogenesis.

Effect of cranberry juice concentrate on chemically-induced urinary bladder cancers

The chemopreventive efficacy of cranberry juice concentrate in an experimental model of urinary bladder cancer was evaluated using female Fischer-344 rats. The animals received N-butyl-N-(4-hydroxybutyl)-nitrosamine (OH-BBN) for a period of eight weeks. Cranberry juice concentrate was administered at doses of 1.0 or 0.5 ml/rat/day beginning one week after the final OH-BBN treatment and continuing until the end of the study. The urinary bladders of all the rats were weighed and examined grossly for lesions, and all masses were submitted for pathological evaluation. A dose-dependent preventive effect of cranberry treatment was observed, with a reduced number of urinary bladder cancers (38%) in the 1.0 ml/rat/day group versus the control group. The cranberry extract neither affected body weight gain nor caused other signs of toxicity. For the metabolic studies, serum and urine were collected at 4 and 12 h after the administration of the cranberry juice concentrate and were analyzed by LC-MS/MS. Quercetin and its methylated derivative were detected in the urine samples. However, no quercetin was detected in the serum samples, indicating its poor bioavailability. These data suggest that components of cranberries may be effective in preventing urinary bladder carcinogenesis.

Chemoprevention of experimental bladder cancer.

The chemopreventive efficacy of several compounds was evaluated in the N-butyl-N-(4-hydroxybutyl)nitrosamine (OH-BBN)-induced urinary bladder cancer model using C57BL/6 x DBA/2F1 (BDF) male mice. Compounds were administered in a defined semipurified diet (AIN-76-A) either as single agents or in combination. As single agents and at the doses employed, 2-alpha-difluoromethylornithine (DFMO), piroxicam, oltipraz, and sodium molybdate effectively inhibited the incidence of transitional cell carcinoma (TCC). 4-Hydroxyphenyl retinamide (4-HPR) was ineffective. Body weight gain and survival was not affected by the doses of agents used. Combinations of two agents which increased efficacy were 4-HPR+DFMO, DFMO+piroxicam, 4-HPR+oltipraz, and DFMO+oltipraz. Three-agent combinations which showed enhanced efficacy against TCC induction were 4-HPR+Na molybdate+DFMO, 4-HPR+DFMO+piroxicam, and 4-HPR+DFMO+oltipraz. Although the three-agent combinations were, for the most part, no more effective than the two-agent combinations at the doses employed, all combination regimens significantly reduced bladder cancer incidence even when single agent administration did not.