Urinary Bladder Carcinogenesis Research Articles

Enhancement of urinary bladder carcinogenesis by combined treatment with benzyl isothiocyanate and N-butyl-N-(4-hydroxybutyl)nitrosamine in rats after initiation.

Previously we reported that benzyl isothiocyanate (BITC) strongly enhanced rat urinary bladder carcinogenesis after initiation with N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN), while potently inhibiting BBN-induction of lesions when given simultaneously with the carcinogen. In the present experiment, the effects of simultaneous treatment with BITC and low-dose BBN on the post-initiation period of rat urinary bladder carcinogenesis were examined. After treatment with 500 ppm BBN for 4 weeks for initiation, groups of 20, 6-week-old, F344 male rats were given 25 ppm BBN alone, basal diet alone, or 100 or 1000 ppm BITC in the diet together with or without 25 ppm BBN in their drinking water for 36 weeks and then killed for autopsy. Further groups consisting of 10 rats each were similarly given BITC or the basal diet together with or without 25 ppm BBN, without initiation treatment. In the initiated groups receiving subsequent BBN exposure, papillary and nodular hyperplasia, dysplasia and carcinoma incidences were significantly increased, and they were further increased by the combined treatment with 100 and 1000 ppm BITC in a dose-dependent manner. In the non-initiation groups, carcinomas were only observed in a single rat in each of the BBN-treated control and BBN/BITC 100 ppm treatment groups. The results indicate that simultaneous treatment with BITC and a low dose of BBN does not inhibit, but rather enhances rat urinary bladder carcinogenesis after appropriate initiation, and further suggest that BITC may be a human risk factor, at least in high-risk populations.

Involvement of Toxicity as an Early Event in Urinary Bladder Carcinogenesis Induced by Phenethyl Isothiocyanate, Benzyl Isothiocyanate, and Analogues in F344 Rats

Involvement of Toxicity as an Early Event in Urinary Bladder Carcinogenesis Induced by Phenethyl Isothiocyanate, Benzyl Isothiocyanate, and Analogues in F344 Rats

High susceptibility of p53 knockout mice to esophageal and urinary bladder carcinogenesis induced by N, N-dibutylnitrosamine

In human cancer, alterations in the p53 tumor suppressor gene are the most common genetic alterations. The aim of the present study was to detect sensitivity of the p53 (+/−) mice and their littermates p53 (+/+) mice to N, N-dibutylnitrosamine (DBN) carcinogenicity. In experiment 1, 6–7-week-old p53 (+/−) and p53 (+/+) mice were treated with 0, 0.025 and 0.05% DBN, respectively, in drinking water for 20 weeks. Esophageal squamous cell and urinary bladder transitional cell carcinomas (TCCs) and fibrosarcomas were found to be significantly increased in p53 (+/−) mice treated with doses of DBN compared to p53 (+/+) mice administered similar doses. In experiment 2, 6–7-week-old p53 (+/−) and p53 (+/+) mice were administered 0 or 0.05 % DBN in drinking water for 8 weeks. Immunohistochemical staining revealed a significant increase in numbers of p53 and bromodeoxyuridine (BrdU) positive cells in the esophageal and urinary bladder epithelia of DBN-treated p53 (+/−) mice compared to p53 (+/+) mice administered DBN. Molecular analysis revealed point mutations in the residual p53 allele in four of eight (50%) esophageal mucosa of DBN-treated p53 (+/−) mice, and in three of eight (38%) of treated p53 (+/+) mice. The results show that p53 (+/−) mice were sensitive to DBN treatment with respect to esophageal and bladder tumor development, with a mechanism that could be confined to early mutations of the residual p53 allele and increased cellular proliferation in the target organs.

Antiangiogenic properties of celecoxib in the N-butyl-N-(4-hydroxy butyl) nitrosamine (BBN)-induced early rat urinary bladder carcinogenesis

Antiangiogenic properties of celecoxib in the N-butyl-N-(4-hydroxy butyl) nitrosamine (BBN)-induced early rat urinary bladder carcinogenesis

Effects of Isoliquirithigenin on the Development of Preneoplastic Liver Lesions Caused by a Choline-Deficient, L-Amino Acid-Defined Diet and on the Urinary Bladder Carcinogenesis by N-Butyl-N-(4-hydroxybutyl)nitrosamine in Rats

Cancer chemopreventive efficacy of a chalcone, isoliquiritigenin (ISO), was assessed on the rat hepatocarcinogenesis associated with fibrosis caused by a choline-deficient, L-amino acid-defined (CDAA) diet, using glutathione S-transferase placental form (GST-P)-positive preneoplastic foci as the end point lesion, and on the rat superficial bladder carcinogenesis initiated by N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN). ISO, when given to F344 male rats at the doses of 12.5, 50, 100, and 200 ppm in the CDAA diet for 15 weeks, did not significantly affect the number and size of GST-P-positive foci and the % liver area occupied by the foci. However, it tended to decrease the grade of liver fibrosis. ISO, which was given in a basal diet at doses of 12.5, 25, and 100 ppm for 12 weeks to F344 male rats initiated by 0.05% BBN in drinking water for 12 weeks, also exhibited no clear chemopreventive effects on the development of urinary bladder tumors. Nevertheless, it tended to decrease the multiplicity of nodulo-papillary hyperplasia but not of transitional cell carcinoma (TCC), and differentiation grade of TCCs. The results indicate that ISO at least at the doses used in the present study, possesses no clear cancer chemopreventive efficacy on rat hepatocarcinogenesis caused by a CDAA diet and on rat superficial urinary bladder carcinogenesis by BBN.

Lack of Influence of Testicular Castration or Sialoadenectomy on Sodium <i>L</i>-Ascorbate Promotion of Urinary Bladder Carcinogenesis in Male F344 Rats

The study was designed to investigate whether testicular castration (TC) or sialoadenectomy (SE) can influence sodium L-ascorbate (Na-AsA)-promoting effects on urinary bladder carcinogenesis in male F344/DuCrj rats. The animals, 6 weeks old at the commencement of the treatment, were given 0.05% N-butyl-N- (4-hydroxybutyl)nitrosamine (BBN) in their drinking water for 4 weeks and then subjected to TC or SE. Thereafter they received basal diet with or without 5% Na-AsA supplement for 32 weeks. Na-AsA caused significant increase in urinary pH, the concentrations of sodium ion, and total ascorbic acid, whereas these urinary parameters were not influenced by TC and SE. TC significantly decreased the relative organ weights of the accessory sexual glands, kidneys, and livers whereas SE was without effect on these organs. TC and SE decreased very slightly BBN-induced carcinogenesis, but TC and SE did not influence the Na-AsA-promoting effects. The present results indicate that Na-AsA-promotion of two-stage urinary bladder carcinogenesis does not depend on the presence of testes or salivary glands.

Dose– and time–response studies of sodium o-phenylphenate urinary bladder carcinogenicity in rats

Dose– and time–response studies of urinary bladder carcinogenesis due to orally administered sodium o-phenylphenate (OPP-Na) were performed using 5-week-old male Fischer 344 rats given diets containing 0 (control), 2500, 5000, 10,000, 15,000 or 20,000 ppm OPP-Na for 104 weeks and fed basal diets until 112 weeks (experiment 1). In addition, rats received diets containing 20,000 ppm OPP-Na for 0 (control), 12, 24, 52 or 104 weeks and were killed at week 112 (experiment 2). In experiment 1, the transitional cell carcinoma (TCC) was the major tumor type in the urinary bladder, and the dose–response curve was steep with many tumors occurring at the high doses of 15,000 and 20,000 ppm. The virtually safe dose at a risk level of 10 −6 for TCCs and papillomas was estimated to be 144 ppm by the Weibull model, a high value similar to that for sodium saccharin. In experiment 2, a few TCCs developed after 24 weeks of treatment, but the time–response curve was also steep with the majority of lesions occurring after longer exposure periods. Based on the observed steepness in dose– and time–responses, any implied cancer risk of OPP-Na at the low doses of interest to man must be considered to be very small.

Simultaneous Treatment With Benzyl Isothiocyanate, a Strong Bladder Promoter, Inhibits Rat Urinary Bladder Carcinogenesis by N-Butyl-N-(4-Hydroxybutyl)Nitrosamine

Effects of benzyl isothiocyanate (BITC) on urinary bladder carcinogenesis were examined in rats simultaneously treated with N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN). Groups of 20 6-wk-old Fischer 344 male rats were given 10, 100, or 1,000 ppm BITC in the diet or a basal diet with 50 ppm BBN in the drinking water for 40 wk and then killed for autopsy. Additional groups consisting of 10 or 9 rats were similarly given BITC or the basal diet alone without BBN treatment. With BBN treatment, dysplasia, papilloma, and carcinoma incidences and multiplicities were dramatically decreased by simultaneous treatment with BITC in a clear dose-dependent manner. In contrast, epithelial hyperplasia was induced in rats treated with 100 and 1,000 ppm BITC without BBN. These results clearly indicate that although BITC may have weak carcinogenic potency, it is a potent chemopreventive agent against bladder tumor induction by BBN.

Urinary bladder carcinogenesis in humans after the chernobyl accident in Ukraine (molecular mechanisms)

Urinary bladder carcinogenesis in humans after the chernobyl accident in Ukraine (molecular mechanisms)

Promoting the effects of intravesical instillation of saline on bladder lesion development in rats pre-treated with BBN.

At present, immunotherapeutic agents such as bacillus Calmette-Guerin (BCG) and anti-tumor chemotherapeutic agents in saline are used intravesically in patients with bladder carcinoma. However, of greater significance is the possibility that the saline vehicle may itself promote carcinoma development in the bladder. The potential promoting effects of intravesical instillation of saline were assessed in female F344 rats. The animals were divided into 3 groups, all of which received 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) in their drinking water for the first 10 weeks. They were then maintained without further treatment (group 1) or received intravesical instillations of 0.3 mL of saline or distilled water once a week for 6 weeks, 15 weeks after the end of the BBN treatment (groups 2 and 3). At 32 weeks, all the animals were killed and examined immunohistochemically with proliferating cell nuclear antigen (PCNA) antibody, as well as by routine histopathologic examination. Both the incidence and the number of bladder carcinomas were higher in the animals that received instillations of saline than in those who did not receive the instillations. Significant increases in tumor size were also noted for the saline-treated groups, although this was not linked with the PCNA labeling index. The results indicate that saline is a promoter of urinary bladder carcinogenesis either because of the catheterization or the fluid itself.

Chemopreventive effects of a flavonoid antioxidant silymarin on N-butyl-N-(4-hydroxybutyl)nitrosamine-induced urinary bladder carcinogenesis in male ICR mice.

The modifying effects of dietary administration of a flavonoid antioxidant, silymarin, a mixture of three flavonoids isolated from milk thistle seeds, on N‐butyl‐.N‐(4‐hydroxybutyl)nitrosamine (OH‐ BBN)‐induced urinary bladder carcinogenesis were examined in male ICR mice. Animals were divided into 5 groups, and groups 1 to 3 were given OH‐BBN (500 ppm) in drinking water for 6 weeks. Mice in group 2 were fed a diet containing 1000 ppm silymarin for 8 weeks during the initiation phase starting 1 week before OH‐BBN exposure, and mice in group 3 were fed the diet for 24 weeks during the postinitiation phase. Animals in group 4 were given only the test compound, and those in group 5 were given the basal diet alone throughout the experiment. Animals were sacrificed at the end of week 32. The frequency of bladder lesions, cell proliferation and cell cycle progression activity estimated in terms of the 5‐bromodeoxyuridine (BrdU) labeling index or cyclin Dl‐positive cell ratio were compared among the groups. Administration of silymarin in the initiation or postinitiation phase significantly decreased the incidences of bladder neoplasms and preneoplastic lesions. Dietary exposure to this agent significantly reduced the labeling index for BrdU and the cyclin Dl‐positive cell ratio in various bladder lesions. These findings suggest that silymarin is effective in preventing OH‐BBN‐induced bladder carcinogenesis in mice.

Lack of enhancing effect of two Kampo medicines, Sho‐saiko‐to (TJ‐9) and Sairei‐to (TJ‐114), on rat urinary bladder carcinogenesis initiated with N‐butyl‐N‐(4‐hydroxybutyl)nitrosamine

The modifying potential of two Kampo medicines (Japanese traditional herbal medicines), Sho-saiko-to (TJ-9) and Sairei-to (TJ-114), on urinary bladder carcinogenesis in male F344 rats initiated with N-butyl-N-(4-hydroxybutyl)- nitrosamine (BBN) was evaluated. Groups of 20 animals were given 0.05% BBN in their drinking water for 4 weeks and then 0.7 or 2.8% TJ-9, 0.9 or 3.6% TJ-114, or 3.0% sodium bicarbonate (NaHCO(3)) as a positive control substance in their diet for 32 weeks. All rats were killed after 36 weeks and examined histopathologically. No adverse effects of the test compounds were found in terms of survival, clinical sign, and body weight. Administration of 0.7 and 2.8% TJ-9 and 0.9 and 3.6% TJ-114 in the diet did not affect the incidences or extent of PN hyperplasia in the BBN-treated rats. Incidences and multiplicities of papillomas were also not affected in rats fed 0.7 or 2.8% TJ-9 and 0.9% TJ-114, while they were significantly decreased in animals given 3.6% TJ-114 in the diet. The results thus demonstrated that neither of the test chemicals exerted any promotional activity on urinary bladder carcinogenesis, in clear contrast to NaHCO(3). In addition, bladder carcinogenesis was reduced by 3.6% TJ-114 in the diet, under the present experimental conditions.

Sulindac inhibited gene expression and activity of arylamine N-acetyltransferase and DNA-2-aminofluorene adduct formation in T24 human bladder tumor cells.

We demonstrated in vivo that non-steroidal anti-inflammatory drugs including sulindac can act as inhibitors of urinary bladder carcinogenesis in rats. The aim of the present study was to determine whether sulindac affects arylamine N-acetyltransferase (NAT) activity and gene expression and DNA-2-aminofluorene adduct formation in the T24 human bladder tumor cell line. The NAT activity (N-acetylation of 2-aminofluorene) was measured by high performance liquid chromatography assaying for the amount of acetylated 2-aminofluorene and the remaining 2-aminofluorene (AF). The results demonstrated that NAT activity in T24 cells were inhibited by the sulindac in a dose-dependent manner. The apparent values of Km and Vmax of NAT from T24 cells were also decreased by sulindac. This inhibition was not competitive. The amount of DNA-AF adduct formation in T24 cells was also inhibited by sulindac. The data also demonstrated that sulindac inhibited the NAT mRNA level in T24 cells.

FAMILIAL BLADDER CANCER IN THE NATIONAL SWEDISH FAMILY CANCER DATABASE

We analyzed the risk of bladder cancer in offspring according to parental and sibling cancer using the national Swedish Family Cancer Database. Cancer data were obtained from the Swedish Cancer Registry for 1958 to 1996, including 2,105 cases of bladder cancer in offspring. The standardized incidence ratio was used to measure cancer risk in offspring according to familial cancer status. The incidence ratio of bladder cancer increased in Sweden from 1958 to 1996 and it was 3 to 4-fold higher in males than in females. We identified 65 families in which the parents and offspring had bladder cancer with a familial risk of 1.35 (95% confidence interval [CI] 0.97 to 1.79) in sons and 2.29 (95% CI 1.46 to 3.29) in daughters. Discordant cancer sites associated with bladder cancer in the 2 generations were the kidney and thyroid with a standardized incidence ratio of 1.58 (95% CI 1.18 to 2.05) and 1.89 (95% CI 1.00 to 3.05), respectively. Sibling risk was higher compared with offspring risk with a standardized incidence ratio of 2.96 (95% CI 1.41 to 5.08) and in males there was a statistically significant ratio of sibling-to-offspring risk of 2.66 (95% CI 1.29 to 5.45). Patient age at onset modified the familial risk. The highest familial risk of 7.26 (95% CI 2.61 to 14.24) was observed in the brothers of bladder cancer probands diagnosed before age 45 years. The relatively high ratio of sibling-to-offspring risk as well as observed gender specific effects in bladder cancer may reflect an X linked susceptibility gene.

Lack of change in the levels of liver and kidney cytochrome P-450 isozymes in p53+/- knockout mice treated with N-butyl-N-(4-hydroxybutyl)nitrosamine.

We have previously shown that p53(+/-) knockout mice are highly sensitive to urinary bladder carcinogenesis induced by N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) in spite of a lack of effects of p53 heterozygosity on N-butyl-N-(3-carboxypropyl)nitrosamine (BCPN) excretion in urine. To determine the influence of p53 deficiency on in vitro formation of BCPN, mutagenicity of BBN and BCPN and levels of several cytochrome P450 (CYP) isozymes, groups of five p53(+/-) knockout and wild-type mice (littermates), as well as animals of the C57BL/6 parental strain, were administered 0.025% BBN in their drinking water for 4 weeks. The livers and kidneys were then used for analyses of BBN metabolism, western immunoblotting and Ames liquid incubation. BBN treatment caused a slight decrease in BCPN formation in the livers of C57BL/6 mice, but there was no significant difference between p53 knockout, wild-type and C57BL/6 mice. In kidney BCPN formation in p53 knockout mice was 33-46% less than that in their wild-type counterparts. Using anti-rat CYP antibodies, CYP1A2, 2B9/10, 2E1 and 3A11/13 were constitutively detected in liver microsomes and CYP2E1 and 3A11/13 in the kidney. Densitometric determination of these CYP proteins revealed no significant variation in levels detected in both tissues among the four groups of mice. BBN and BCPN were not mutagenic for Salmonella typhimurium TA100 in either the absence or presence of liver S9 from untreated mice and rats and from p53 knockout mice treated with BBN. In conclusion, p53 deficiency and BBN had no enhancing effects on metabolism of BBN to BCPN and expression of the CYP isozymes typically responsible for activation of environmental carcinogens, including both of the N-nitrosamines tested, and their mutagenicity, indicating that the high susceptibility of p53(+/-) knockout mice is not attributable to metabolic activation in liver and kidney by CYP isozymes or urinary excretion of BCPN.

Mapping and Genome Sequence Analysis of Chromosome 5 Regions Involved in Bladder Cancer Progression

We studied the evolution of allelic losses on chromosome 5 by whole-organ histologic and genetic mapping in 234 mucosal DNA samples of 5 cystectomy specimens with invasive bladder cancer and preneoplastic changes in adjacent urothelium. The frequency of alterations in individual loci was verified on 32 tumors and 29 voided urine samples from patients with bladder cancer. Finally, deleted regions on chromosome 5 were integrated with the human genome contigs and sequence-based databases. Deleted regions on chromosome 5 involved in intraurothelial phases of bladder neoplasia defined by their nearest flanking markers and predicted size were identified as follows: q13.3-q22 (D5S424-D5S656; 38.8 centimorgan [cM]); q22-q31.1 (D5S656-D5S808; 19.2 cM), q31.1-q32 (D5S816-SPARC; 11.5 cM), and q34 (GABRA1-D5S415; 6.4 cM). The two most frequently deleted neighbor markers (D5S2055 and D5S818) mapping to q22-q31.1 defined a 9 cM region, which may contain genes that play an important role in early phases of urinary bladder carcinogenesis. Human genome database analysis provided an accurate map of deleted regions with positions of 138 known genes and revealed several smaller gene-rich areas representing putative targets for further mapping. The strategic approach presented here, which combines whole-organ histologic and genetic mapping with analysis of the rapidly emerging human genome sequence database, facilitates identification of genes potentially involved in early phases of bladder carcinogenesis.

The effects of organ resection on rat urinary bladder carcinogenesis.

The effect of unilateral nephrectomy, orchiectomy or partial hepatectomy on the growth of chemically induced rat bladder tumors was investigated. Male F344 rats were treated with 0.05% N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) for 5 weeks, and surgical resection of one of these organs was performed 2 weeks after the completion of BBN administration. Histological evaluation of the bladder 24 weeks after the start of the experiment revealed that unilateral nephrectomy and orchiectomy significantly increased the numbers of preneoplastic and neoplastic lesions as compared with the corresponding sham-operated groups. Partial hepatectomy also enhanced tumor growth, although not significantly. Immunohistochemical studies examining the effect of organ resection on normal bladder urothelium showed that BrdU immunostaining of urothelial cells significantly increased 7 days after unilateral nephrectomy or orchiectomy, while BrdU incorporation was minimum after partial hepatectomy or sham operation. C-met expression in the bladder urothelium was evident following unilateral nephrectomy or partial hepatectomy, while increased immunoreactivity of androgen receptor was noted following unilateral orchiectomy. Further study is needed to determine the exact mechanism of the bladder tumor growth-enhancing effect associated with organ restriction.

Possible involvement of O 6-methylguanine formation and p53 dysfunction in mouse urinary bladder carcinogenesis

The significance of O 6-methylguanine formation in urinary bladder carcinogenesis was examined using O 6-methylguanine-DNA methyltransferase ( MGMT) transgenic mice carrying the ada gene. The ada MGMT transgenic mice demonstrated no differences in development of carcinogens-induced urinary bladder carcinomas compared with non-transgenic mice. Furthermore, no variation in p53 mutation frequency was evident between the two groups. The results indicated that other repair systems may have an important role for urinary bladder carcinogenesis. p53 knockout mice showed high sensitivity to urinary bladder carcinogens and increased cell proliferation plays an important role in urinary bladder carcinogenicity of p53 knockout mice. In addition, p53 knockout mice have an organ-specific increased sensitivity to carcinogenicity.

Dose-Dependent Promotion by Phenylethyl Isothiocyanate, a Known Chemopreventer, of Two-Stage Rat Urinary Bladder and Liver Carcinogenesis

The effects of phenylethyl isothiocyanate (PEITC) on urinary bladder and liver carcinogenesis were analyzed in a rat model. Diets containing 0.1%, 0.05%, or 0.01% PEITC were administered for 32 wk to male Fischer 344 rats with and without pretreatment with an injection of diethylnitrosamine (200 mg/kg body wt ip) and 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine in the drinking water for 4 wk for initiation. In the initiated groups, PEITC administration significantly increased the incidences of papillary or nodular hyperplasia, dysplasia, and transitional cell carcinomas at higher doses of 0.01%, 0.01%, and 0.05%, respectively, compared with the control group, given initiation alone, in a dose-dependent manner. Without initiation, administration of 0.1% and 0.05% PEITC induced simple and papillary or nodular hyperplasia and dysplasia in the urinary bladder. In the liver, induction of glutathione S-transferase placental form-positive foci was dose dependently enhanced by PEITC administration, but the incidences of liver tumors were not different among the groups. From the present experiment, we can conclude that >0.01% PEITC enhances rat urinary bladder carcinogenesis, while weakly promoting hepatocarcinogenesis. In addition, it is suggested that >0.05% PEITC has tumorigenic potential.

Antitumoral effect of recombinant mistletoe lectin on chemically induced urinary bladder carcinogenesis in a rat model

Antitumoral effect of recombinant mistletoe lectin on chemically induced urinary bladder carcinogenesis in a rat model