Experimental intravesical therapy for superficial transitional cell carcinoma in a rat bladder tumor model

Intravesical BCG Induces CD4+ T-Cell Expansion in an Immune Competent Model of Bladder Cancer

Intravesical bacillus Calmette-Guérin (BCG) immunotherapy is the standard of care in treating non-muscle-invasive bladder cancer, yet its mechanism of action remains elusive. Both innate and adaptive immune responses have been implicated in BCG activity. Although prior research has indirectly demonstrated the importance of T cells and shown a rise in CD4+ T cells in bladder tissue after BCG, T-cell subpopulations have not been fully characterized. We investigated the relationship between effector and regulatory T cells in an immune competent, clinically relevant rodent model of bladder cancer. Our data demonstrate that cancer progression in the N-methyl-N-nitrosourea (MNU) rat model of bladder cancer was characterized by a decline in the CD8/FoxP3 ratio, consistent with decreased adaptive immunity. In contrast, treatment with intravesical BCG led to a large, transient rise in the CD4+ T-cell population in the urothelium and was both more effective and immunogenic compared with intravesical chemotherapy. Whole-transcriptome expression profiling of posttreatment intravesical CD4+ and CD8+ T cells revealed minimal differences in gene expression after BCG treatment. Together, our results suggest that although BCG induces T-cell recruitment to the bladder, the T-cell phenotype does not markedly change, implying that combining T-cell-activating agents with BCG might improve clinical activity. Cancer Immunol Res; 5(7); 594-603. ©2017 AACR.

Preventive effect of intravesical ozone supplementation on n-methyl-n-nitrosourea-induced non-muscle invasive bladder cancer in male rats

Although non-muscle invasive bladder cancer (NMIBC) is widely seen in men, most laboratory studies of new intravesical therapies to prevent NMIBC have been conducted on female animals. In addition, ozone (O₃) has been shown to be a beneficial agent as an intravesical application in the treatment of various disorders. In the current study, we evaluated the immunohistopathological and oxidative-antioxidative effects of intravesical O₃ treatment on n-methyl-n-nitrosourea (MNU)-induced NMIBC. Male Wistar-Albino rats (n=51) were divided into four groups: sham (n=6), O₃ only (n=15), MNU only (n=15), and MNU+O₃ (n=15). The MNU-only and MNU+O₃ groups received MNU, and the O₃-only group received saline every other week for 10 weeks. The MNU-only group received 1 ml saline in place of O₃ treatment, whereas the O₃-only and MNU+O₃ groups were treated with 1 ml 25 µg/ml O₃ between the 7th and 12th weeks. Rat bladders were collected in the 15th week for immunohistopathology and oxidant-antioxidant quantitation. Oxidant-antioxidant parameters were determined by ELISA. Although all surviving rats in the MNU-only group had preneoplastic (4/11, 36.4%) or neoplastic changes (7/11, 63.6%), a completely normal urothelium was observed in 2 rats (2/12, 16.7%) in the MNU+O₃-group (P=0.478). More high-grade lesions were observed in the MNU-only group (4/11, 36.4%) than in the MNU+O₃ group (1/12, 8.3%) (P=0.120). All oxidant-antioxidant parameters significantly increased (P<0.05) in the O₃-only group compared with the sham group. However, only antioxidant superoxide dismutase was remarkably higher (178.9%, P=0.060) in the MNU+O₃ group compared with the MNU-only group. This is the first methodologically and pathologically well-described male rat orthotopic bladder carcinogenesis model with intravesical MNU and administration of O₃ in NMIBC.

Metformin can block precancerous progression to invasive tumors of bladder through inhibiting STAT3-mediated signaling pathways

BACKGROUND

Metformin is the first line of oral antidiabetic drug in the biguanide class for treatment of type 2 diabetes. Increasing evidence has suggested that it is a potential anti-tumor drug. However, the mechanisms underlying inhibiting tumor development remain elusive, especially in bladder tumors.

METHODS

T24 and J82 cell lines were used as an in vitro model, and 24 female SD rats were used to build an N-methyl-N-nitrosourea (MNU)-induced orthotopic rat bladder cancer model. Transfection of lentivirus-based shRNA was used to construct the STAT3-KNOCKDOWN T24 cell line. After metformin treatment, the viability of bladde cancer cells was determined by CCK8. Cell cycle distribution and apoptosis were assessed by flow cytometry. The migration and invasion abilities of cells were evaluated by wound healing and transwell asssays. The inactivation of stat3 pahtway was examined by qRTPCR, western blot and Immunofluorescence.

RESULTS

Metformin can effectively inhibit precancerous progression to invasive cancer in an MNU-induced rat orthotopic bladder tumor model, although it could not completely suppress normal cells transforming into tumor cells. While the MNU could induce 50 % rats (4/8) to develop invasive bladder cancers, the rats co-administrated with metformin failed to develop invasive tumors but retained at precancerous or non-invasive stages, exhibiting as dysplasia, papillary tumor and/or carcinoma in situ (CIS). Accordingly, phosphorylation of signal transducer and activator of transcription 3 (STAT3), which is a well known oncogene, was significantly inhibited in the tumors of rats treated with metformin. In vitro experiments revealed that the metformin could efficiently inhibit STAT3 activation, which was associated with the cell cycle arrest, reduction of cell proliferation, migration and invasiveness, and increase in apoptotic cell death of bladder cancer cell lines.

CONCLUSIONS

These findings provide for the first time the evidence that metformin can block precancerous lesions progressing to invasive tumors through inhibiting the activation of STAT3 pathway, and may be used for treatment of the non-invasive bladder cancers to prevent them from progression to invasive tumors.

Urothelial carcinogen resistance driven by stronger Toll-like receptor 2 (TLR2) and Uroplakin III (UP III) defense mechanisms: a new model

OBJECTIVE

The objective of the study was to illustrate the applicability and significance of the novel Lewis urothelial cancer model compared to the classic Fisher 344.

METHODS

Fischer 344 and Lewis females rats, 7 weeks old, were intravesical instilled N-methyl-N-nitrosourea 1.5 mg/kg every other week for a total of four doses. After 15 weeks, animals were sacrificed and bladders analyzed: histopathology (tumor grade and stage), immunohistochemistry (apoptotic and proliferative indices) and blotting (Toll-like receptor 2-TLR2, Uroplakin III-UP III and C-Myc). Control groups received placebo.

RESULTS

There were macroscopic neoplastic lesions in 20 % of Lewis strain and 70 % of Fischer 344 strain. Lewis showed hyperplasia in 50 % of animals, normal bladders in 50 %. All Fischer 344 had lesions, 20 % papillary hyperplasia, 30 % dysplasia, 40 % neoplasia and 10 % squamous metaplasia. Proliferative and apoptotic indices were significantly lower in the Lewis strain (p < 0.01). The TLR2 and UP III protein levels were significantly higher in Lewis compared to Fischer 344 strain (70.8 and 46.5 % vs. 49.5 and 16.9 %, respectively). In contrast, C-Myc protein levels were significantly higher in Fischer 344 (22.5 %) compared to Lewis strain (13.7 %).

CONCLUSIONS

The innovative Lewis carcinogen resistance urothelial model represents a new strategy for translational research. Preservation of TLR2 and UP III defense mechanisms might drive diverse urothelial phenotypes during carcinogenesis in differently susceptible individuals.

Effects of P-MAPA Immunomodulator on Toll-Like Receptors and p53: Potential Therapeutic Strategies for Infectious Diseases and Cancer

Background

Compounds that can act as agonists for toll-like receptors (TLRs) may be promising candidates for the development of drugs against infectious diseases and cancer. The present study aimed to characterize the immunomodulatory effects of P-MAPA on TLRs in vitro and in vivo, as well as to investigate its potential as adjuvant therapy in infectious diseases and cancer.

Methods

For these purposes, the activity of P-MAPA on TLRs was assayed in vitro through NF-κB activation in HEK293 cells expressing a given TLR, and using an in vivo animal model for bladder cancer (BC). The antimicrobial activity of P-MAPA was tested against Mycobacterium tuberculosis (TB) in vitro in an MIC assay, and in vivo using an aerosol infection model of murine tuberculosis. Antitumor effects of P-MAPA were tested in an animal model with experimentally induced BC. Moxifloxacin (MXF) and Bacillus Calmette-Guerin (BCG) were used as positive controls in the animal models.

Results

The results showed that P-MAPA, administered alone or in combination with MXF, induced significant responses in vivo against TB. In contrast, the compound did not show antimicrobial activity in vitro. P-MAPA showed a significant stimulatory effect on human TLR2 and TLR4 in vitro. In BC, TLR2, TLR4 and p53 protein levels were significantly higher in the P-MAPA group than in the BCG group. The most common histopathological changes in each group were papillary carcinoma in BC group, low-grade intraepithelial neoplasia in BCG group and simple hyperplasia in P-MAPA group. Concerning the toxicological analysis performed during BC treatment, P-MAPA did not show evidence for hepatotoxicity and nephrotoxicity.

Conclusions

In conclusion, P-MAPA acted as TLR ligand in vitro and improved the immunological status in BC, increasing TLR2 and TLR4 protein levels. P-MAPA immunotherapy was more effective in restoring p53 and TLRs reactivities and showed significantly greater antitumor activity than BCG. The activation of TLRs and p53 may provide a hypothetical mechanism for the therapeutic effects in both cancer and infectious diseases. Taken together data obtained will encourage the further investigation of P-MAPA as a potential candidate for the treatment of cancer and infectious diseases.

Evolution on experimental animal model for upper urothelium carcinogenesis

PURPOSE

No optimal, well designed and reproducible animal model for upper urothelial carcinogenesis exists. This study characterized the histopathological features on top of immunolocalization of alpha-dystroglycans (alpha-DG) and matrix metalloproteinase (MMP-9) and cell turn-over in the upper urinary tract using a novel experimental model.

METHODS

Seventy-five female Fischer 344 rats were divided into three groups: the control group received a 0.30-ml dose of 0.9% physiological saline; the MNU group (chemical carcinogen N-methyl-N-nitrosourea) received 0.30 ml of MNU; and the MNU-citrate group received 0.30 ml of MNU plus sodium citrate, every one intravesically every other week for a total of 4 doses. After 15 weeks, bladder, ureters and renal pelvis were collected for morphological and molecular analysis.

RESULTS

Associated management with MNU and sodium citrate was able to lead to 100% of both urinary bladder and upper urinary tract tumors, being the high-grade noninvasive papillary urothelial carcinoma the most frequent lesion. The upper urothelium showed reduced alpha-DG and increased MMP-9 and Ki-67 immunoreactivities in the MNU-citrate group in relation to the other groups. MNU group presented no upper urothelium tumor and 100% bladder tumor.

CONCLUSIONS

This is a relevant evolution on experimental animal model for upper urinary tract carcinogenesis field. MMP-dependent disruption of the DG complex plays an important role in urothelial tumor carcinogenesis and showed the model applicability and significance. MNU-citrate model could contribute to a better understanding of human upper urothelial cancer development as well as to its local treatment strategies in a near future.

A novel Bifidobacterium infantis-mediated TK/GCV suicide gene therapy system exhibits antitumor activity in a rat model of bladder cancer

Bladder cancer is the ninth most common malignancy in the world. Successful clinical management remains a challenge. In order To search for novel targeted and efficacious treatment, we sought to investigate anti-tumor activity of BI-TK suicide gene therapy system in a rat model of bladder tumors. We first constructed and tested an anaerobic Bifidobacterium infantis-mediated thymidine kinase (BI-TK) suicide gene therapy system. To test the in vivo efficacy of this system, we established a rat model of bladder tumors, which was induced by N-methyl-nitrosourea perfusion. Bifidobacterium infantis containing the HSV-TK (i.e., BI-TK) were constructed by transformation of recombinant plasmid pGEX - TK. The engineered BI-TK was injected into tumor-bearing rats via tail vein, followed by intraperitoneal injection of ganciclovir (GCV). Using the rat model of bladder tumors, we found that bladder tumor burdens were significantly lower in the rats treated with BI-TK/GCV group than that treated with normal saline control group (p <0.05). While various degrees of apoptosis of the tumor cells were detected in all groups using in situ TUNEL assay, apoptosis was mostly notable in the BI-TK/GCV treatment group. Immunohistochemical staining further demonstrated that the BI-TK/GCV treatment group had the highest level of caspase3 protein expression than that of the empty plasmid group and normal saline group (p < 0.05). Thus, our results demonstrate that the Bifidobacterium infantis-mediated TK/GCV suicide gene therapy system can effectively inhibit rat bladder tumor growth, possibly through increasing caspase 3 expression and inducing apoptosis.

Experimental animal model and RNA interference: a promising association for bladder cancer research

Animal models are at the centre of laboratory bladder cancer (BC) research and at the same time, the bridge to the clinic. A new and very promising therapeutical approach is to silence abnormally up-regulated genes in cancer, through small interfering RNA (siRNA) molecules. Therapeutic use and success of siRNAs will largely depend on their efficient and safe in vivo delivery and on avoiding accidental off-target effects. Intravesical siRNA is a strategy which may be the best deliver option to surperficial BC like intravesical immunotherapy. Its direct action might allow a continuous intracellular exposure to effective siRNA concentrations. While the procedure of transurethral siRNA administration is promising for BC research allowing detection of new targets in BC therapy, the optimal intravesical carrier and the best target(s) to siRNA are to be determined.

Effects of curcumin on bladder cancer cells and development of urothelial tumors in a rat bladder carcinogenesis model

Curcumin, a well-known dietary pigment derived from Curcuma longa, inhibited growth of several types of malignant cells both in vivo and in vitro. Its effects on cell proliferation and the induction of apoptosis in human bladder cancer cell lines and intravesical activity in a rat bladder tumor model were studied. Exposure of human bladder cancer cells to curcumin resulted in the induction of apoptotic cell death and caused cells to arrest in the G2/M phase. The anti-apoptotic Bcl-2 and Survivin protein was downregulated by the curcumin treatment together with enhancement of the Bax and p53 expression. The inhibitory activities of curcumin were stronger than those of cisplatin and could not be prevented by catalase pretreatment in T24 cells. Clonal assay indicated large-dose and short-term curcumin was lethal to bladder cancer cells. Moreover, the in vivo study revealed curcumin did induce apoptosis in situ, inhibit and slow the development of bladder cancer. These observations suggest that curcumin could prove an effective chemopreventive and chemotherapy agent for bladder cancer.

FLUORESCENCE GUIDED OPTICAL COHERENCE TOMOGRAPHY FOR THE DIAGNOSIS OF EARLY BLADDER CANCER IN A RAT MODEL

PURPOSE

We describe the technique of fluorescence image guided optical coherence tomography (FG-OCT). We examined its ability to enhance specificity and sensitivity for the noninvasive diagnosis of early bladder cancer.

MATERIALS AND METHODS

Transitional cell carcinoma was developed in 54 Fisher 344 female rats by intravesical methyl-nitroso-urea instillations. Two or three rats were diagnosed sequentially by 5-ALA (5-aminolevulinic acid hydrochloride) induced fluorescence imaging, cross-sectional OCT and histological microscopy weekly during weeks 11 to 33 following initial methyl-nitroso-urea instillation to track the course of carcinogenesis.

RESULTS

The specificity of fluorescence detection was significantly enhanced by FG-OCT (53% and 93%, respectively, p <0.0001). The sensitivity of fluorescence detection and FG-OCT was 79% and 100%, respectively.

CONCLUSIONS

FG-OCT cystoscopy has the potential to diagnose early bladder cancer with high sensitivity and specificity with drastically decreased imaging time compared to that of white light guided OCT cystoscopy.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

The results indicate that saline is a promoter of urinary bladder carcinogenesis either because of the catheterization or the fluid itself.

Detection of tumorigenesis in rat bladders with optical coherence tomography

Optical coherence tomography (OCT) is a novel technique that enables noninvasive cross-sectional imaging of biological tissues. Because of its high resolution (approximately 10 microm), superior dynamic range (140 dB in our case) and up to 2-3 mm penetration depth, OCT is potentially useful for noninvasive screening of superficial lesions. Bladder cancer arises within the transitional epithelium. Despite the ability to visualize the epithelium via cystoscopy, it is often difficult to detect early epithelial cancers and to determine their penetration to the underlying layers. To investigate the potential of OCT to enhance imaging of bladder cancers and other epithelial lesions, we applied OCT to normal and diseased bladder epithelium, and correlated the results with histological findings. OCT images of porcine bladder (a close homolog of human bladder) confirm the ability of this method to image human tissues. To determine whether OCT can track the course of bladder cancer, a standard rat model of bladder cancer in which Fisher rats are exposed to methyl-nitroso-urea (MNU), was followed both with OCT and histological studies. Our results show that the micro morphology of porcine bladder such as the urothelium, submucosa and muscles is identified by OCT and well correlated with the histological evaluations. OCT detected edema, inflammatory infiltrates, and submucosal blood congestion as well as the abnormal growth of urothelium (e.g., papillary hyperplasia and carcinomas). By contrast, surface imaging, which resembles cystoscopy, provided far less sensitivity and resolution than OCT. This is the first OCT study of any tumor documented in a systematic fashion, and the results suggest the potential of OCT for the noninvasive diagnosis of both bladder inflammatory lesions and early urothelial abnormalities, which conventional cystoscopy often misses, by imaging characterization of the increases in urothelial thickening and backscattering. However, because of the depth limitation, OCT may have limited applications in staging the invasion of higher-state urothelial cancers, especially for papillary carcinomas.

Promoting effects of intravesical instillation of saline on bladder lesion development in rats pretreated with N-butyl-N-(4-hydroxybutyl) nitrosamine are inhibited by bacillus Calmette-Guerin

The promoting effects of intravesical instillation of saline and the efficacy of bacillus Calmette-Guerin (BCG) for prophylaxis of bladder carcinogenesis were assessed. Rats were given 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) for 10 weeks; they were then given 6 weekly intravesical instillations of BCG, saline or distilled water starting 1 week or 15 weeks after the BBN treatment. At 32 weeks, both the incidences and numbers of bladder cancers were elevated in animals receiving the saline. An exception was the early phase BCG group. Significant increases in tumor size were also noted for the saline, but not the distilled water group. The results indicate that intravesical instillation of saline promotes urinary bladder carcinogenesis. However, the inhibitory influence of BCG was suggested if administered at the early, but not the late phase, of carcinogenesis.

Is there a role for recombinant tumor necrosis factor alpha in the intravesical treatment of superficial bladder tumors?--a phase II study

Clinical use of recombinant tumor necrosis factor-alpha is strongly limited by its severe toxicity, mainly cardiovascular, when systemically administered. Recent studies suggest that topical (intrapleural, intraperitoneal, intratumoral) administration is free of significant toxicity. Human recombinant tumor necrosis factor-alpha was administered intravesically, at a dose of 500 mg dissolved in 30 ml of phosphate buffer (pH 7.6-7.8) plus 0.25% human albumin, weekly for two months to 18 patients with papillary transitional cell carcinoma of the bladder. Of the 15 evaluable patients, four (26%) achieved a complete response. Systemic and local tolerability were excellent.

Intravesical suramin in the prevention of transitional cell carcinoma

OBJECTIVES

To examine the effects of intravesical suramin on N-methyl-N-nitrosurea (MNU)-induced bladder tumors in Fischer 344 rats.

METHODS

Multiple cohorts of female rats received four biweekly intravesical instillations of MNU. A control group received no other treatment, the experimental group received 25 mg/kg intravesical suramin twice a week beginning at week 6.

RESULTS

After 18 weeks from the first instillation of MNU, 60% to 65% of control animals developed papillary transitional cell carcinoma, compared with only 0% to 10% of the suramin-treated animals (P = 0.01 to P = 0.0007). There was no local or systemic toxicity observed.

CONCLUSIONS

Intravesical suramin is an effective chemopreventative therapy for transitional cell carcinoma in vivo with minimal toxicity.

Critical review of the models to study the biologic progression of bladder cancer

For transitional cell carcinoma of the bladder, clinical data indicate that invasive, metastatic tumors can arise through at least two different progression pathways. The majority of invasive, metastatic bladder neoplasms clinically present de novo, i.e., the patients have no history of malignant bladder disease. This implies that the highly malignant tumor cells either arise de novo or have undergone a rapid progression. Alternatively, a considerable fraction of patients with superficial bladder cancer process to invasive disease after a history of relatively benign superficial TCC. The molecular and cell biological basis of tumor progression is only poorly understood. Clearly, a better understanding of this progress could have profound clinical implications, since patients with superficial TCC with a high risk for progression would have to be treated more aggressively. We discuss the problems that are associated with tumor biological studies on early steps in the progression of TCC, especially from a "model system point of view."