An improved intravesical model using human bladder cancer cell lines to optimize gene and other therapies

Establishment of Mouse Orthotopic Urinary Bladder Tumor Model and Its Analysis by Light and Electron Microscopy

Mouse tumor models are an important tool in cancer research, and the orthotopic cancer cell transplantation model is the most widely used among them. Methods for establishing tumor models may differ in many ways, including the selection of cancer cell lines and the type of urinary bladder pretreatment. Here, we describe our mouse orthotopic bladder tumor model using a labeled MB49 urothelial cancer cell line and chemical pretreatment with the cationic polypeptide poly-L-lysine to traumatize the bladder epithelium. Double labeling of MB49 cancer cells by their transduction with GFP and internalization of metal nanoparticles allows the study of their implantation process from the first hours to several days after intravesical injection, as well as the analysis of developed tumors after 3 weeks. Thus, our model provides a comprehensive analysis of the early and late stages of tumor development in the bladder at the light and electron microscopic level.

A surgical orthotopic approach for studying the invasive progression of human bladder cancer

The invasion of bladder cancer into the sub-urothelial muscle and vasculature are key determinants leading to lethal metastatic progression. However, the molecular basis is poorly understood, partly because of the lack of uncomplicated and reliable models that recapitulate the biology of locally invasive disease. We developed a surgical grafting technique, characterized by a simple, rapid, reproducible and high-efficiency approach, to recapitulate the pathobiological events of human bladder cancer invasion in mice. This technique consists of a small laparotomy and direct implantation of human cancer cells into the bladder lumen. Unlike other protocols, it does not require debriding of the urothelial lining, injection into the bladder wall, specialized imaging equipment, bladder catheterization or costly surgical equipment. With minimal practice, the procedure can be executed in <10 min. Tumors develop with a high take rate, and most cell lines exhibit local invasion within 4 weeks of implantation.

Targeting an Autocrine Regulatory Loop in Cancer Stem-like Cells Impairs the Progression and Chemotherapy Resistance of Bladder Cancer

PURPOSE

Cancer stem-like cells (CSCs) contribute to bladder cancer chemotherapy resistance and progression, but the associated mechanisms have not been elucidated. This study determined whether blocking an autocrine signaling loop in CSCs improves the therapeutic effects of cis-platinum on bladder cancer.

EXPERIMENTAL DESIGN

The expression of the epithelial marker OV6 and other markers in human bladder cancer specimens was examined by IHC. The CSC properties of magnetic-activated cell sorting (MACS)-isolated OV6⁺ and OV6^- bladder cancer cells were examined. Molecular mechanisms were assessed through RNA-Seq, cytokine antibody arrays, co-immunoprecipitation (co-IP), chromatin immunoprecipitation (ChIP) and other assays. An orthotopic bladder cancer mouse model was established to evaluate the in vivo effects of a YAP inhibitor (verteporfin) and a PDGFR inhibitor (CP-673451) on the cis-platinum resistance of OV6⁺ CSCs in bladder cancer.

RESULTS

Upregulated OV6 expression positively associated with disease progression and poor prognosis for bladder cancer patients. Compared with OV6^- cells, OV6⁺ bladder cancer cells exhibited strong CSC characteristics, including self-renewal, tumor initiation in NOD/SCID mice, and chemotherapy resistance. YAP, which maintains the stemness of OV6⁺ CSCs, triggered PDGFB transcription by recruiting TEAD1. Autocrine PDGF-BB signaling through its receptor PDGFR stabilized YAP and facilitated YAP nuclear translocation. Furthermore, blocking the YAP/TEAD1/PDGF-BB/PDGFR loop with verteporfin or CP-673451 inhibited the cis-platinum resistance of OV6⁺ bladder cancer CSCs in an orthotopic bladder cancer model.

CONCLUSIONS

OV6 could be a helpful indicator of disease progression and prognosis for patients with bladder cancer, and targeting the autocrine YAP/TEAD1/PDGF-BB/PDGFR loop might serve as a remedy for cis-platinum resistance in patients with advanced bladder cancer.

How cancer cells attach to urinary bladder epithelium in vivo: study of the early stages of tumorigenesis in an orthotopic mouse bladder tumor model

The majority of bladder cancers in humans are non-muscle-invasive cancers that recur frequently after standard treatment procedures. Mouse models are widely used to develop anti-tumor treatments. The purpose of our work was to establish an orthotopic mouse bladder tumor model and to explore early stages of implantation of cancerous MB49 cells in vivo using various labeling and microscopic techniques. To distinguish cancer cells from normal urothelial cells in mouse urinary bladders, we performed molecular characterization of MB49 cells before intravesical injection experiments. In this new approach we applied internalized metal nanoparticles to unequivocally discriminate cancer cells from normal cells. This method revealed that cancer cells attached to the urothelium or basal lamina within just 1 hour of intravesical injection, whereas small tumors and localized hyperplastic urothelial regions developed within two days. We found that cancer cells initially adhere to normal urothelial cells through filopodia and by focal contacts with basal lamina. This is the first in vivo characterization of intercellular contacts between cancerous and normal urothelial cells in the bladder. Our study yields new data about poorly known early events of tumorigenesis in vivo, which could be helpful for the translation into clinic.

Phage Display-Derived Peptide-Based Dual-Modality Imaging Probe for Bladder Cancer Diagnosis and Resection Postinstillation: A Preclinical Study

Bladder cancer is a common human malignancy. Conventional ultrasound and white-light cystoscopy are often used for bladder cancer diagnosis and resection, but insufficient specificity results in a high bladder cancer recurrence rate. New strategies for the diagnosis and resection of bladder cancer are needed. In this study, we developed a highly specific peptide-based probe for bladder cancer photoacoustic imaging (PAI) diagnosis and near-infrared (NIR)-imaging-guided resection after instillation. A bladder cancer-specific peptide (PLSWT7) was selected by in vivo phage-display technology and labeled with IRDye800CW to synthesize a bladder cancer-specific dual-modality imaging (DMI) probe (PLSWT7-DMI). The feasibility of PLSWT7-DMI-based dual-modality PAI-NIR imaging was assessed in vitro, in mouse models, and ex vivo human bladders. An air-pouch bladder cancer (APBC) model suitable for probe instillation was established to evaluate the probe-based bladder cancer PAI diagnosis and NIR-imaging-guided resection. Human bladders were used to assess whether the PLSWT7-DMI-based DMI strategy is a translatable approach for bladder cancer detection and resection. The probe exhibited excellent selectivity and specificity both in vitro and in vivo Postinstillation of the probe, tumors <3 mm were detectable by PAI, and NIR-imaging-guided tumor resection decreased the bladder cancer recurrence rate by 90% and increased the survival in the mouse model. Additionally, ex vivo NIR imaging of human bladders indicated that PLSWT7-DMI-based imaging would potentially allow precise resection of bladder cancer in clinical settings. This PLSWT7-DMI-based DMI strategy was a translatable approach for bladder cancer diagnosis and resection and could potentially lower the bladder cancer recurrence rate. Mol Cancer Ther; 17(10); 2100-11. ©2018 AACR.

Electrostatic interaction of tumor-targeting adenoviruses with aminoclay acquires enhanced infectivity to tumor cells inside the bladder and has better cytotoxic activity

In a previous report, 3-aminopropyl functionalized magnesium phyllosilicate (aminoclay) improved adenovirus transduction efficiency by shielding the negative surface charges of adenovirus particles. The present study analyzed the physicochemical characterization of the electrostatic complex of adenoviruses with aminoclay and explored whether it could be utilized for enhancing tumor suppressive activity in the bladder. As a result of aminoclay-adenovirus nanobiohybridization, its transduction was enhanced in a dose-dependent manner, increasing transgene expression in bladder cancer cells and in in vivo animal models. Physicochemical studies demonstrated that positively charged aminoclay led to the neutralization of negative surface charges of adenoviruses, protection of adenoviruses from neutralizing antibodies and lowered transepithelial electrical resistance (TEER). As expected from the physicochemical properties, the aminoclay enabled tumor-targeting adenoviruses to be more potent in killing bladder cancer cells and suppressing tumor growth in orthotopic bladder tumors, suggesting that aminoclay would be an efficient, versatile and biocompatible delivery carrier for intravesical instillation of adenoviruses.

An orthotopic xenograft model for high-risk non-muscle invasive bladder cancer in mice: influence of mouse strain, tumor cell count, dwell time and bladder pretreatment

Background

Novel theranostic options for high-risk non-muscle invasive bladder cancer are urgently needed. This requires a thorough evaluation of experimental approaches in animal models best possibly reflecting human disease before entering clinical studies. Although several bladder cancer xenograft models were used in the literature, the establishment of an orthotopic bladder cancer model in mice remains challenging.

Methods

Luciferase-transduced UM-UC-3^LUCK1 bladder cancer cells were instilled transurethrally via 24G permanent venous catheters into athymic NMRI and BALB/c nude mice as well as into SCID-beige mice. Besides the mouse strain, the pretreatment of the bladder wall (trypsin or poly-L-lysine), tumor cell count (0.5 × 10⁶–5.0 × 10⁶) and tumor cell dwell time in the murine bladder (30 min – 2 h) were varied. Tumors were morphologically and functionally visualized using bioluminescence imaging (BLI), magnetic resonance imaging (MRI), and positron emission tomography (PET).

Results

Immunodeficiency of the mouse strains was the most important factor influencing cancer cell engraftment, whereas modifying cell count and instillation time allowed fine-tuning of the BLI signal start and duration – both representing the possible treatment period for the evaluation of new therapeutics. Best orthotopic tumor growth was achieved by transurethral instillation of 1.0 × 10⁶ UM-UC-3^LUCK1 bladder cancer cells into SCID-beige mice for 2 h after bladder pretreatment with poly-L-lysine. A pilot PET experiment using ⁶⁸Ga-cetuximab as transurethrally administered radiotracer revealed functional expression of epidermal growth factor receptor as representative molecular characteristic of engrafted cancer cells in the bladder.

Conclusions

With the optimized protocol in SCID-beige mice an applicable and reliable model of high-risk non-muscle invasive bladder cancer for the development of novel theranostic approaches was established.

Periostin suppresses in vivo invasiveness via PDK1/Akt/mTOR signaling pathway in a mouse orthotopic model of bladder cancer

Periostin is an extracellular matrix protein involved in the regulation of intercellular adhesion. The present study investigated the in vivo tumor suppressor function of periostin in a mouse orthotopic model of bladder cancer. Retroviral vectors were used to transfect human bladder cancer UMUC-3 cell line with periostin. Bladders of nude mice that were transurethrally instilled with periostin-expressing UMUC-3 cells were revealed to weigh less compared with bladders instilled with vector control cells. In total, five (83.3%) of six vector control UMUC-3 bladder tumors exhibited histological evidence of muscle invasion. However, none of the five periostin-expressing UMUC-3 bladder tumors revealed muscle invasion. Thick edematous lesions were present in the submucosa of periostin-expressing UMUC-3 bladder tumors. The expression of periostin also suppressed in vitro cell invasiveness of UMUC-3 cells without affecting cellular proliferation. The level of phosphorylation of phosphoinositide-dependent kinase-1 (PDK1), protein kinase B (Akt) and S6 ribosomal protein, a downstream protein of mammalian target of rapamycin (mTOR) was decreased in periostin-expressing UMUC-3 cells compared with vector control cells. Treatment with 100 ng/ml recombinant human periostin protein also suppressed cell invasiveness and phosphorylation of PDK1, Akt and S6 in UMUC-3 cells, consistent with results using periostin-expressing UMUC-3 cells. Treatment with PDK1, Akt and mTOR inhibitors significantly suppressed UMUC-3 cell invasiveness. These results demonstrate that periostin suppresses in vivo and in vitro invasiveness of bladder cancer via the PDK1/Akt/mTOR signaling pathway. Periostin may be useful as a potent chemotherapeutic agent by suppressing bladder cancer invasiveness.

Aldo-keto reductase 1C1 induced by interleukin-1β mediates the invasive potential and drug resistance of metastatic bladder cancer cells

In treating bladder cancer, determining the molecular mechanisms of tumor invasion, metastasis, and drug resistance are urgent to improving long-term patient survival. One of the metabolic enzymes, aldo-keto reductase 1C1 (AKR1C1), plays an essential role in cancer invasion/metastasis and chemoresistance. In orthotopic xenograft models of a human bladder cancer cell line, UM-UC-3, metastatic sublines were established from tumors in the liver, lung, and bone. These cells possessed elevated levels of EMT-associated markers, such as Snail, Slug, or CD44, and exhibited enhanced invasion. By microarray analysis, AKR1C1 was found to be up-regulated in metastatic lesions, which was verified in metastatic human bladder cancer specimens. Decreased invasion caused by AKR1C1 knockdown suggests a novel role of AKR1C1 in cancer invasion, which is probably due to the regulation of Rac1, Src, or Akt. An inflammatory cytokine, interleukin-1β, was found to increase AKR1C1 in bladder cancer cell lines. One particular non-steroidal anti-inflammatory drug, flufenamic acid, antagonized AKR1C1 and decreased the cisplatin-resistance and invasion potential of metastatic sublines. These data uncover the crucial role of AKR1C1 in regulating both metastasis and drug resistance; as a result, AKR1C1 should be a potent molecular target in invasive bladder cancer treatment.

Fractionated intravesical radioimmunotherapy with (213)Bi-anti-EGFR-MAb is effective without toxic side-effects in a nude mouse model of advanced human bladder carcinoma

Gold standard in therapy of superficial, non-muscle invasive urothelial tumors is transurethral resection followed by intravesical instillation therapies. However, relapse is commonly observed and therefore new therapeutic approaches are needed. Application of (213)Bi-immunoconjugates targeting EGFR had shown promising results in early tumor stages. The aim of this study was the evaluation of fractionated application of (213)Bi-anti-EGFR-MAb in advanced tumor stages in a nude mouse model. Luciferase-transfected EJ28 human bladder carcinoma cells were instilled intravesically into nude mice following electrocautery. Tumor development was monitored via bioluminescence imaging. One day after tumor detection mice were treated intravesically either 2 times with 0.93 MBq or 3 times with 0.46 MBq of (213)Bi-anti-EGFR-MAb. Therapeutic efficacy was evaluated via overall survival and toxicity toward normal urothelium by histopathological analysis. Mice without treatment and those treated with the native anti-EGFR-MAb showed mean survivals of 65.4 and 57.6 d, respectively. After fractionated treatment with 0.93 MBq of (213)Bi-anti-EGFR-MAb animals reached a mean survival of 141.5 d and 33% of the animals survived at least 268 d. Fractionated treatment with 0.46 MBq (213)Bi-anti-EGFR-MAb resulted in a mean survival of 131.8 d and 30% of the animals survived longer than 300 d. Significant differences were only observed between the control groups and the group treated twice with 0.93 MBq of (213)Bi-anti-EGFR-MAb. No toxic side-effects on the normal urothelium were observed even after treatment with 3.7 MBq of (213)Bi-anti-EGFR-MAb. The study demonstrates that the fractionated intravesical radioimmunotherapy with (213)Bi-anti-EGFR-MAb is a promising approach in advanced bladder carcinoma.

P70S6K and Elf4E dual inhibition is essential to control bladder tumor growth and progression in orthotopic mouse non-muscle invasive bladder tumor model

We investigated how the dual inhibition of the molecular mechanism of the mammalian target of the rapamycin (mTOR) downstreams, P70S6 kinase (P70S6K) and eukaryotic initiation factor 4E (eIF4E), can lead to a suppression of the proliferation and progression of urothelial carcinoma (UC) in an orthotopic mouse non-muscle invasive bladder tumor (NMIBT) model. A KU-7-luc cell intravesically instilled orthotopic mouse NMIBC model was monitored using bioluminescence imaging (BLI) in vivo by interfering with different molecular components using rapamycin and siRNA technology. We then analyzed the effects on molecular activation status, cell growth, proliferation, and progression. A high concentration of rapamycin (10 µM) blocked both P70S6K and elF4E phosphorylation and inhibited cell proliferation in the KU-7-luc cells. It also reduced cell viability and proliferation more than the transfection of siRNA against p70S6K or elF4E. The groups with dual p70S6K and elF4E siRNA, and rapamycin reduced tumor volume and lamina propria invasion more than the groups with p70S6K or elF4E siRNA instillation, although all groups reduced photon density compared to the control. These findings suggest that both the mTOR pathway downstream of eIF4E and p70S6K can be successfully inhibited by high dose rapamycin only, and p70S6K and Elf4E dual inhibition is essential to control bladder tumor growth and progression.

Tumour multifocality and grade predict intravesical recurrence after nephroureterectomy in patients with upper urinary tract urothelial carcinoma without a history of bladder cancer

OBJECTIVE

Patients with upper urinary tract urothelial carcinoma (UUT-UC) without a history of bladder cancer have a different natural history of intravesical recurrence after nephroureterectomy compared with those with a history of bladder cancer. The aim of this study was to identify predictive factors for post-operative intravesical recurrence in patients with non-metastatic upper urinary tract-localized urothelial carcinoma without a history of bladder cancer and who were not taking medication during the perioperative period.

METHODS

This retrospective study included 133 patients who were treated between 1995 and 2012. Univariate and multivariate analyses were used to evaluate the clinical and pathological factors associated with the cumulative incidence of bladder cancer.

RESULTS

Of the 133 patients, 51 (38.3%) developed intravesical recurrence during a median follow-up of 71 months (range, 0.8-210.8). In the multivariate analysis, multifocality (P = 0.03) and high tumour grade (P = 0.007) were significantly associated with the cumulative incidence of bladder cancer. We constructed a prediction classification model on the basis of the total number of risk factors. The 2-year cumulative incidence rates were 5.6, 34.8 and 50.0% in individuals with no, one and two risk factors, respectively. There was a significant difference between patients with no risk factors and those with two risk factors (P = 0.01).

CONCLUSIONS

Although this retrospective study had several limitations, tumour multifocality and tumour grade were found to be potential risk factors for intravesical recurrence in our cases.

Animal models for bladder cancer: The model establishment and evaluation (Review)

Bladder cancer is the most common type of tumor in the urogenital system. Approximately 75% of patients with bladder cancer present with non-muscle-invasive cancer, which is generally treated by transurethral resection and intravesical chemotherapy. In spite of different therapeutic options, there remains a very variable risk of recurrence and progression. Novel therapeutic methods of treating bladder cancer are urgently required. The exploration and preclinical evaluation of new treatments requires an animal tumor model that mimics the human counterpart. Animal models are key in bladder cancer research and provide a bridge to the clinic. Various animal bladder cancer models have been described to date, but the tumor take rate is reported to be 30-100%. Establishment of reliable, simple, practicable and reproducible animal models remains an ongoing challenge. The present review summarizes the latest developments with regard to the establishment of animal models and tumor evaluation.

Current animal models of bladder cancer: Awareness of translatability (Review)

Experimental animal models are crucial in the study of biological behavior and pathological development of cancer, and evaluation of the efficacy of novel therapeutic or preventive agents. A variety of animal models that recapitulate human urothelial cell carcinoma have thus far been established and described, while models generated by novel techniques are emerging. At present a number of reviews on animal models of bladder cancer comprise the introduction of one type of method, as opposed to commenting on and comparing all classifications, with the merits of a certain method being explicit but the shortcomings not fully clarified. Thus the aim of the present study was to provide a summary of the currently available animal models of bladder cancer including transplantable (which could be divided into xenogeneic or syngeneic, heterotopic or orthotopic), carcinogen-induced and genetically engineered models in order to introduce their materials and methods and compare their merits as well as focus on the weaknesses, difficulties in operation, associated problems and translational potential of the respective models. Findings of these models would provide information for authors and clinicians to select an appropriate model or to judge relevant preclinical study findings. Pertinent detection methods are therefore briefly introduced and compared.

Establishment of an orthotopic mouse non-muscle invasive bladder cancer model expressing the mammalian target of rapamycin signaling pathway

We established an orthotopic non-muscle invasive bladder cancer (NMIBC) mouse model expressing the mammalian target of the rapamycin (mTOR) signaling pathway. After intravesical instillation of KU-7-lucs (day 0), animals were subsequently monitored by bioluminescence imaging (BLI) on days 4, 7, 14, and 21, and performed histopathological examination. We also validated the orthotopic mouse model expressing the mTOR signaling pathway immunohistochemically. In vitro BLI photon density was correlated with KU-7-luc cell number (r (2) = 0.97, P < 0.01) and in vivo BLI photon densities increased steadily with time after intravesical instillation. The tumor take rate was 84.2%, formed initially on day 4 and remained NMIBC up to day 21. T1 photon densities were significantly higher than Ta (P < 0.01), and histological tumor volume was positively correlated with BLI photon density (r (2) = 0.87, P < 0.01). The mTOR signaling pathway-related proteins were expressed in the bladder, and were correlated with the western blot results. Our results suggest successful establishment of an orthotopic mouse NMIBC model expressing the mTOR signaling pathway using KU-7-luc cells. This model is expected to be helpful to evaluate preclinical testing of intravesical therapy based on the mTOR signaling pathway against NMIBC.

Enhanced antitumor efficacy of integrin-targeted oncolytic adenovirus AxdAdB3-F/RGD on bladder cancer

OBJECTIVE

To evaluate the therapeutic efficacy of AxdAdB-3 with Arg-Gly-Asp (RGD)-fiber modification (AxdAdB3-F/RGD), which enables integrin-dependent infection in bladder cancers.

METHODS

Flow cytometric analysis was applied to evaluated adenovirus-mediated gene transduction into various cells. The cytopathic effects of AxdAdB3-F/RGD were evaluated in bladder cancer cell lines and a normal bladder mucosa-derived cell line (HCV29) with AxCAZ3-F/RGD (control) or AxdAdB-3. The efficacy of bladder instillation therapy with AxdAdB3-F/RGD for orthotopic bladder cancer was investigated in nude mice.

RESULTS

Expression of coxsackievirus adenovirus receptor (CAR) and integrins (αvβ3 and αvβ5) vary in different bladder cancer cell lines. The susceptibility of various cell lines to adenovirus was associated with the expression of CAR. AxdAdB-3 was more cytopathic in CAR-positive bladder cancer cells than in CAR-negative cells, whereas AxdAdB3-F/RGD caused effective oncolysis in both CAR-positive and CAR-negative bladder cancer cells. AxdAdB3-F/RGD was not cytotoxic to HCV29 cells. Direct instillation of AxdAdB3-F/RGD into the bladder of the orthotopic model, established by CAR-deficient human bladder cancer cells, inhibited tumor growth and led to significantly elongated survival.

CONCLUSION

E1A and E1B double-restricted oncolytic adenovirus with RGD fiber modification has enhanced infectivity and oncolytic effects to CAR-deficient bladder cancers, suggesting the therapeutic potential of AxdAdB3-F/RGD for bladder cancers.

Preconditioning methods influence tumor property in an orthotopic bladder urothelial carcinoma rat model

Urothelial carcinoma (UC) is an extremely common type of cancer that occurs in the bladder. It has a particularly high rate of recurrence. Therefore, preclinical studies using animal models are essential to determine effective forms of treatment. In the present study, in order to establish an orthotopic bladder UC animal model with clinical relevance, the effects of preconditioning methods on properties of the developed tumor were evaluated. The bladder cavity was pretreated with phosphate-buffered saline (PBS), acid-base, trypsin (TRY) or poly (L-lysine) (PLL) and then rat UC cells (AY-27) (4×10⁶ cells) were inoculated. The results demonstrated that, two weeks later, the tumorigenic rate (88%) and tumor count (2.3 per rat) were not significantly different among the preconditioning methods, whereas tumor volume and invasion depth into bladder tissue were significantly different. Average tumor volumes were >50 mm³ in the PBS and acid-base-treated groups and <10 mm³ in the TRY- and PLL-treated groups. The percentage of invasive tumors (T2 or more advanced stage) was ∼75% of total tumors in the PBS- and acid-base-treated groups, whereas the percentages were reduced in the TRY- and PLL-treated groups (58 and 32%, respectively). Non-invasive tumors (Ta or T1) accounted for 54% of tumors in the PLL-treated group, which was 2-5-fold higher than the percentages in the remaining groups. Properties of the developed tumor in the rat orthotopic UC model were different depending on preconditioning methods. Therefore, different animal models suitable for a discrete preclinical examination may be established by using the appropriate preconditioning condition.

Investigation of CCL18 and A1AT as potential urinary biomarkers for bladder cancer detection

BACKGROUND

In this study, we further investigated the association of two biomarkers, CCL18 and A1AT, with bladder cancer (BCa) and evaluated the influence of potentially confounding factors in an experimental model.

METHODS

In a cohort of 308 subjects (102 with BCa), urinary concentrations of CCL18 and A1AT were assessed by enzyme-linked immunosorbent assay (ELISA). In an experimental model, benign or cancerous cells, in addition to blood, were added to urines from healthy controls and analyzed by ELISA. Lastly, immunohistochemical staining for CCL18 and A1AT in human bladder tumors was performed.

RESULTS

Median urinary protein concentrations of CCL18 (52.84 pg/ml vs. 11.13 pg/ml, p < 0.0001) and A1AT (606.4 ng/ml vs. 120.0 ng/ml, p < 0.0001) were significantly elevated in BCa subjects compared to controls. Furthermore, the addition of whole blood to pooled normal urine resulted in a significant increase in both CCL18 and A1AT. IHC staining of bladder tumors revealed CCL18 immunoreactivity in inflammatory cells only, and there was no significant increase in these immunoreactive cells within benign and cancerous tissue and no association with BCa grade nor stage was noted. A1AT immunoreactivity was observed in the cytoplasm of epithelia cells and intensity of immunostaining increased with tumor grade, but not tumor stage.

CONCLUSIONS

Further development of A1AT as a diagnostic biomarker for BCa is warranted.

Development and characterization of a bladder cancer xenograft model using patient-derived tumor tissue

Most of the cancer xenograft models are derived from tumor cell lines, but they do not sufficiently represent clinical cancer characteristics. Our objective was to develop xenograft models of bladder cancer derived from human tumor tissue and characterize them molecularly as well as histologically. A total of 65 bladder cancer tissues were transplanted to immunodeficient mice. Passagable six cases with clinico-pathologically heterogeneous bladder cancer were selected and their tumor tissues were collected (012T, 025T, 033T, 043T, 048T, and 052T). Xenografts were removed and processed for the following analyses: (i) histologic examination, (ii) short tandem repeat (STR) genotyping, (iii) mutational analysis, and (iv) array-based comparative genomic hybridization (array-CGH). The original tumor tissues (P 0) and xenografts of passage 2 or higher (≥P2) were analyzed and compared. As a result, hematoxylin and eosin staining revealed the same histologic architecture and degree of differentiation in the primary and xenograft tumors in all six cases. Xenograft models 043T_P2 and 048T_P2 had completely identical STR profiles to the original samples for all STR loci. The other models had nearly identical STR profiles. On mutational analysis, four out of six xenografts had mutations identical to the original samples for TP53, HRAS, BRAF, and CTNNB1. Array-CGH analysis revealed that all six xenograft models had genomic alterations similar to the original tumor samples. In conclusion, our xenograft bladder cancer model derived from patient tumor tissue is expected to be useful for studying the heterogeneity of the tumor populations in bladder cancer and for evaluating new treatments.

Therapeutic effects of microRNA-582-5p and -3p on the inhibition of bladder cancer progression

Many reports have indicated that the abnormal expression of microRNAs (miRNAs) is associated with the progression of disease and have identified miRNAs as attractive targets for therapeutic intervention. However, the bifunctional mechanisms of miRNA guide and passenger strands in RNA interference (RNAi) therapy have not yet been clarified. Here, we show that miRNA (miR)-582-5p and -3p, which are strongly decreased in high-grade bladder cancer clinical samples, regulate tumor progression in vitro and in vivo. Significantly, the overexpression of miR-582-5p or -3p reduced the proliferation and invasion of UM-UC-3 human bladder cancer cells. Furthermore, transurethral injections of synthetic miR-582 molecule suppressed tumor growth and metastasis in an animal model of bladder cancer. Most interestingly, our study revealed that both strands of miR-582-5p and -3p suppressed the expression of the same set of target genes such as protein geranylgeranyltransferase type I beta subunit (PGGT1B), leucine-rich repeat kinase 2 (LRRK2) and DIX domain containing 1 (DIXDC1). Knockdown of these genes using small interfering RNA (siRNA) resulted in the inhibition of cell growth and invasiveness of UM-UC-3. These findings uncover the unique regulatory pathway involving tumor suppression by both strands of a single miRNA that is a potential therapeutic target in the treatment of invasive bladder cancer.

miRNA-100 inhibits human bladder urothelial carcinogenesis by directly targeting mTOR

miRNAs are involved in cancer development and progression, acting as tumor suppressors or oncogenes. In this study, miRNA profiling was conducted on 10 paired bladder cancer tissues using 20 GeneChip miRNA Array, and 10 differentially expressed miRNAs were identified in bladder cancer and adjacent noncancerous tissues of any disease stage/grade. After being validated on expanded cohort of 67 paired bladder cancer tissues and 10 human bladder cancer cell lines by quantitative real-time PCR (qRT-PCR), it was found that miR-100 was downregulated most significantly in cancer tissues. Ectopic restoration of miR-100 expression in bladder cancer cells suppressed cell proliferation and motility, induced cell-cycle arrest in vitro, and inhibited tumorigenesis in vivo both in subcutaneous and in intravesical passage. Bioinformatic analysis showed that the mTOR gene was a direct target of miR-100. siRNA-mediated mTOR knockdown phenocopied the effect of miR-100 in bladder cancer cell lines. In addition, the cancerous metastatic nude mouse model established on the basis of primary bladder cancer cell lines suggested that miR-100/mTOR regulated cell motility and was associated with tumor metastasis. Both mTOR and p70S6K (downstream messenger) presented higher expression levels in distant metastatic foci such as in liver and kidney metastases than in primary tumor. Taken together, miR-100 may act as a tumor suppressor in bladder cancer, and reintroduction of this mature miRNA into tumor tissue may prove to be a therapeutic strategy by reducing the expression of target genes.

Antitumor effects of exogenous ganglioside GM3 on bladder cancer in an orthotopic cancer model

OBJECTIVE

To investigate the therapeutic effects of exogenous gangliosides GM3 on human bladder cancer cell lines and the severe combined immunodeficiency mouse model of orthotopic bladder cancer.

MATERIALS AND METHODS

Human bladder cancer cell lines YTS-1, T24, 5637, and KK47 were used in the study. In vitro cytotoxicity of GM3 was assessed using the cell counting kit-8. Cell adhesion was determined using a spreading assay. Phosphorylation of epidermal growth factor receptor was determined by Western blotting. In vivo, the orthotopic bladder cancer model was established using severe combined immunodeficiency mice and GM3 was administered intravesically by way of a transurethral catheter.

RESULTS

GM3 inhibited the proliferation of all the bladder cancer cell lines tested. The addition of GM3 decreased cell adhesion and epidermal growth factor-dependent phosphorylation of epidermal growth factor receptor. Direct instillation of GM3 into the bladder of the orthotopic model significantly inhibited tumor growth.

CONCLUSION

Our results suggest exogenous GM3 as a potential therapeutic agent for treating bladder cancer.

Intravesical delivery of small activating RNA formulated into lipid nanoparticles inhibits orthotopic bladder tumor growth

Practical methods for enhancing protein production in vivo remain a challenge. RNA activation (RNAa) is emerging as one potential solution by using double-stranded RNA (dsRNA) to increase endogenous gene expression. This approach, although related to RNA interference (RNAi), facilitates a response opposite to gene silencing. Duplex dsP21-322 and its chemically modified variants are examples of RNAa-based drugs that inhibit cancer cell growth by inducing expression of tumor suppressor p21(WAF1/CIP1) (p21). In this study, we investigate the therapeutic potential of dsP21-322 in an orthotopic model of bladder cancer by formulating a 2'-fluoro-modified derivative (dsP21-322-2'F) into lipid nanoparticles (LNP) for intravesical delivery. LNP composition is based upon clinically relevant formulations used in RNAi-based therapies consisting of PEG-stabilized unilamellar liposomes built with lipid DLin-KC2-DMA. We confirm p21 induction, cell-cycle arrest, and apoptosis in vitro following treatment with LNP-formulated dsP21-322-2'F (LNP-dsP21-322-2'F) or one of its nonformulated variants. Both 2'-fluoro modification and LNP formulation also improve duplex stability in urine. Intravesical delivery of LNP-dsP21-322-2'F into mouse bladder results in urothelium uptake and extends survival of mice with established orthotopic human bladder cancer. LNP-dsP21-322-2'F treatment also facilitates p21 activation in vivo leading to regression/disappearance of tumors in 40% of the treated mice. Our results provide preclinical proof-of-concept for a novel method to treat bladder cancer by intravesical administration of LNP-formulated RNA duplexes.

Multifunctional targeting micelle nanocarriers with both imaging and therapeutic potential for bladder cancer

Background

We previously developed a bladder cancer-specific ligand (PLZ4) that can specifically bind to both human and dog bladder cancer cells in vitro and in vivo. We have also developed a micelle nanocarrier drug-delivery system. Here, we assessed whether the targeting micelles decorated with PLZ4 on the surface could specifically target dog bladder cancer cells.

Materials and methods

Micelle-building monomers (ie, telodendrimers) were synthesized through conjugation of polyethylene glycol with a cholic acid cluster at one end and PLZ4 at the other, which then self-assembled in an aqueous solution to form micelles. Dog bladder cancer cell lines were used for in vitro and in vivo drug delivery studies.

Results

Compared to nontargeting micelles, targeting PLZ4 micelles (23.2 ± 8.1 nm in diameter) loaded with the imaging agent DiD and the chemotherapeutic drug paclitaxel or daunorubicin were more efficient in targeted drug delivery and more effective in cell killing in vitro. PLZ4 facilitated the uptake of micelles together with the cargo load into the target cells. We also developed an orthotopic invasive dog bladder cancer xenograft model in mice. In vivo studies with this model showed the targeting micelles were more efficient in targeted drug delivery than the free dye (14.3×; P < 0.01) and nontargeting micelles (1.5×; P < 0.05).

Conclusion

Targeting micelles decorated with PLZ4 can selectively target dog bladder cancer cells and potentially be developed as imaging and therapeutic agents in a clinical setting. Preclinical studies of targeting micelles can be performed in dogs with spontaneous bladder cancer before proceeding with studies using human patients.

Direct cytotoxicity produced by adenoviral-mediated interferon α gene transfer in interferon-resistant cancer cells involves ER stress and caspase 4 activation

Over the past several years we have obtained considerable evidence indicating that adenoviruses-expressing interferon α (Ad-IFNα) can overcome resistance to the IFNα protein itself. Since cancer cells infected with Ad-IFNα also show high perinuclear cytoplasmic IFNα expression, we were interested in whether endoplasmic reticulum (ER) stress and cleavage of caspase 4 could have a major role in Ad-IFNα-produced cancer cell death. Indeed, procaspase 4 was upregulated and cleaved as early as 12 h after Ad-IFNα infection of the cancer cells, which co-localized with IFNα staining and ER tracker. In contrast, immortalized normal human urothelial cells, although exhibiting similar perinuclear IFNα staining, showed no cleaved caspase 4. Caspase 4 cleavage was not blocked by the caspase 8 specific inhibitor zIETD, indicating that caspase 4 activation was independent of caspase 8 activation. Blocking caspase 4 also inhibited activation of caspase 3 in Ad-IFNα containing cells. Finally, the cleaved form of caspase 4 (p10) was detected in Ad-IFNα-positive cancer cells from the urine of a patient following intravesical Ad-IFNα/Syn3 treatment. Therefore, ER stress and activation of caspase 4 appears to be an important mechanism involved in the direct cancer cell death produced by Ad-IFNα and also occurs in the clinical setting.

Real-time cancer cell tracking by bioluminescence in a preclinical model of human bladder cancer growth and metastasis

BACKGROUND

Bladder cancer is the fifth most common malignancy in the Western world and the second most frequently diagnosed genitourinary tumor. In the majority of cases, death from bladder cancer results from metastatic disease. Understanding the multistep process of carcinogenesis and metastasis in urothelial cancers is pivotal to the development of new therapeutic strategies. Molecular imaging of cancer growth and metastasis in preclinical models provides the essential link between cell-based experiments and clinical translation.

OBJECTIVE

Develop preclinical models for sensitive bladder cancer cell tracking during tumor progression and metastasis.

DESIGN, SETTING, AND PARTICIPANTS

A human transitional cell carcinoma UM-UC-3 cell line was generated that stably expresses luciferase 2 (UM-UC-3luc2), a mammalian codon-optimized firefly luciferase with superior expression. Preclinical models were developed with human UM-UC-3luc2 cells xenografted into the bladder (orthotopic model with metastases) or inoculated into the left cardiac ventricle (bone metastasis model) of immunocompromised mice.

MEASUREMENTS

Noninvasive, sensitive bioluminescent imaging of human firefly luciferase 2-positive bladder cancer in mice using the IVIS100 imaging system.

RESULTS AND LIMITATIONS

In the orthotopic model (intravesical inoculation), tumor growth could be followed directly after inoculation of UM-UC-3luc2 cells. Importantly, micrometastatic lesions originating from orthotopically implanted cancer cells could be detected in the locoregional lymph nodes and in distant organs. In addition, the superior bioluminescent indicator firefly luciferase 2 allows the detection and monitoring of micrometastatic lesions in real time after intracardiac inoculation of human bladder cancer cells in mice. The main disadvantage is the lack of T-cell immunity in the preclinical models.

CONCLUSIONS

The new bioluminescence-based preclinical bladder cancer models enable superior, noninvasive, and real-time tracking of cancer cells, tumor progression, and micrometastasis. Because of the significant improvement in detection of small cell numbers, the presented models are ideally suited for functional studies dealing with minimal residual disease as well as real-time imaging of drug response.

Optimum conditions of ultrasound-mediated destruction of bubble liposome for siRNA transfer in bladder cancer

Background: We investigated the effectiveness of ultrasound-mediated destruction of bubble liposome (UBL) for siRNA transfer by observing reduction in the luciferase activity of human bladder tumor RT-112 cells transfected with the luciferase gene (RT-112Luc) following luciferase siRNA transfer into the cells. Results: siRNA was transferred to 26% of RT-112Luc cells by UBL and the luciferase activity of RT-112Luc cells was significantly suppressed by UBL using the luciferase siRNA, compared with that using nonspecific siRNA in vitro (p = 0.036). The luciferase activity of RT-112Luc tumor was suppressed by UBL using luciferase siRNA compared with that using nonspecific siRNA 2 days after the in vivo treatment. Conclusion: This study showed that UBL is suitable for siRNA transfer to mammalian cells.

Mouse models of human bladder cancer as a tool for drug discovery

Muscle-invasive bladder cancer is a deadly condition in dire need of effective new treatments. This unit contains a description of mouse models suitable for the evaluation of potential new therapies. Included is a genetically engineered mouse model of bladder cancer generated by the delivery of an adenovirus expressing Cre recombinase into the bladder lumen. Also described is an orthotopic mouse model created by the instillation of human bladder tumor cells into the bladder lumen of immune deficient mice. Protocols are also provided on the use of these models for the preclinical evaluation of new chemical entities, with mTOR inhibitors shown as an example.

Optimizing orthotopic bladder tumor implantation in a syngeneic mouse model

PURPOSE

We established a reliable technique for orthotopically implanting bladder tumor cells in a syngeneic mouse model.

MATERIALS AND METHODS

MBT-2 murine bladder cancer cells were transurethrally implanted in the bladder of syngeneic C3H/He mice (Jackson Laboratory, Bar Harbor, Maine). Different chemical pretreatments were used before tumor implantation, including phosphate buffered saline (control), HCl, trypsin and poly-L-lysine. MBT-2 cells (1 x 10(6) or 2 x 10(6)) were instilled into the intravesical space after chemical pretreatment. Tumor take and bladder tumor volume were determined by micro ultrasound. Bladders were harvested at the end of the study to measure bladder weight and for histopathological examination.

RESULTS

Bladder pretreatment with HCl in 5 preparations was discontinued due to significant adverse reactions, resulting in death in 1 mouse, and severe bladder inflammation and hematuria 3 days after pretreatment in 2. Pretreatment with phosphate buffered saline, trypsin and poly-L-lysine in 6 animals each was tolerated well without significant adverse reactions or mortality. The tumor take rate in the control, trypsin and poly-L-lysine pretreatment groups was 33%, 83% and 83%, respectively. The take rate was higher in mice instilled with 2 x 10(6) cells than in those with 1 x 10(6) cells (93% vs 73%, p <0.05).

CONCLUSIONS

We report a reliable, feasible method of orthotopically implanting bladder tumor cells into a syngeneic mouse model. Poly-L-lysine and trypsin are useful adjunctive pretreatment agents to improve bladder tumor uptake. This model may be suitable to evaluate treatment paradigms for bladder cancer.

Bladder cancer: modeling and translation

Transitional cell carcinoma of the bladder is a common malignancy worldwide that is associated with significant morbidity and mortality. Although superficial tumors can often be treated effectively, invasive cancers not only require invasive surgery, but are also refractory to aggressive chemotherapy and radiotherapy. In this issue of Genes & Development, Puzio-Kuter and colleagues (pp. 675-680) describe an elegant genetically engineered murine model of bladder cancer that recapitulates many of the cardinal features of the human disease. The development of such models together with the application of new approaches to enumerate the complement of genetic alterations in bladder will provide new insights into the molecular nature of this disease. Moreover, the anatomy of this urinary malignancy provides a unique opportunity for innovative translational studies.

Experimental rat bladder urothelial cell carcinoma models

Bladder cancer is a major public health problem. Currently available therapeutic options seem to be unable to prevent bladder cancer recurrence and progression. To enable preclinical testing of new intravesical therapeutic agents, a suitable bladder tumor model that resembles human disease is highly desirable. The aim of this topic paper was to discuss the problems associated with current in vivo animal bladder tumor models, focusing on the orthotopic syngeneic rat bladder tumor model. In the second part of the paper the development of a potential new orthotopic rat bladder tumor model is described.

[Oncolytic vesicular stomatitis viruses as intravesical agents against non-muscle-invasive bladder cancer]

Patients with high-risk bladder cancer who do not respond to bacillus Calmette-Guerin (BCG) immunotherapy represent a significant therapeutic challenge. The addition of interferon to BCG has recently evolved as a second-line treatment option; however, many high-grade tumors are nonresponsive to interferon. Thus, replication-competent oncolytic vesicular stomatitis viruses (VSV) that selectively target interferon-refractory tumors are promising intravesical agents. In vitro, wild-type VSV as well as a mutant variant (AV3) that has an impaired ability to shut down innate immunity preferentially killed undifferentiated, interferon-nonresponsive bladder cancer cells. Testing of these viruses in an orthotopic murine model of high-grade bladder cancer, which we have recently validated, revealed that both AV3 and wild-type VSV significantly inhibited orthotopic tumor growth. Despite the use of immunocompromised nude mice, there was no evidence of toxicity. In conclusion, VSV instillation therapy demonstrated strong antitumor activity and safety in an orthotopic model of high-risk disease. These findings provide preclinical proof-of-principle for the intravesical use of VSV, especially in interferon-refractory patients.

Establishment of orthotopic mouse superficial bladder tumor model for studies on intravesical treatments

Various animal models of bladder tumor have been developed for the preclinical evaluation of therapeutic modalities for the treatment of bladder cancers. The ideal model for the investigation of therapeutic effects of proposed novel intravesical treatments requires the mass of the implanted tumor to be confined to the urothelium of the bladder at least for the initial phase. However, previously reported bladder tumor models are not suitable for the evaluation of intravesical therapies for the treatment of superficial bladder cancer, since the muscle invasive tumors have developed from the beginnings of the experiments. These models are too aggressive to study local treatment effects. In the current study, we demonstrated that careful instillation of MBT-2 mouse bladder cancer cells into the bladder of a syngenic C3H/HeJ mouse could establish a superficial bladder tumor with an incidence of 100%. The procedure and technique for handling animals are simple for standard animal investigators. Maintenance of the in vitro conditions of MBT-2 cells without contamination of Mycoplasma and careful selection of the substrain of C3H mouse seem to be essential for stable tumor establishment. This bladder tumor model appeared to be easy to reproduce among several investigators in different institutions. The orthotopic bladder tumor model, which was confined to urothelium, lets us evaluate various intravesical treatment strategies.

Tumor-targeting nanocomplex delivery of novel tumor suppressor RB94 chemosensitizes bladder carcinoma cells in vitro and in vivo

PURPOSE

RB94, a truncated form of RB110, has enhanced tumor suppressor potency and activity against all tumor types tested to date including bladder carcinoma. However, efficient, systemic delivery of the gene encoding RB94 specifically to tumors, is an obstacle to clinical application as an anticancer therapeutic. We have developed a systemically given, nanosized liposome DNA delivery system that specifically targets primary and metastatic disease. The ability of RB94, delivered via this nanocomplex, to sensitize bladder carcinoma to chemotherapy in vitro and in vivo was assessed.

EXPERIMENTAL DESIGN

The nanocomplex is an RB94 plasmid encapsulated by a cationic liposome, the surface of which is decorated with a tumor-targeting moiety, either transferrin (Tf/Lip/RB94) or an antitransferrin receptor single-chain antibody fragment (TfRScFv/Lip/RB94). The ability of the complex to sensitize human bladder carcinoma HTB-9 cells to chemotherapeutics was assessed in vitro by XTT assay. In vivo tumor specificity and efficacy were tested in mice carrying HTB-9 tumors by PCR and tumor growth inhibition, respectively.

RESULTS

Transfection with Tf/Lip/RB94 significantly sensitized HTB-9 cells to chemotherapeutic agents in vitro. Tumor specificity of the complex was shown in an orthotopic bladder tumor model by immunohistochemistry and PCR. Moreover, in mice bearing subcutaneous HTB-9 tumors, the combination of systemically given Tf/Lip/RB94 or TfRScFv/Lip/RB94 plus gemcitabine resulted in significant (P<0.0005) tumor growth inhibition/regression and induction of apoptosis.

CONCLUSIONS

Use of our tumor-targeting nanocomplex to specifically deliver the potent tumor suppressor RB94 efficiently to tumors has potential as a more effective treatment modality for genitourinary and other cancers.

Intravesical chemotherapy of high-grade bladder cancer with HTI-286, a synthetic analogue of the marine sponge product hemiasterlin

PURPOSE

HTI-286 is a fully synthetic analogue of the natural tripeptide hemiasterlin that inhibits tubulin polymerization and has strong cytotoxic potential. In this study, we evaluate the inhibitory effects of HTI-286 on human bladder cancer growth, both in vitro and as an intravesical agent in an orthotopic murine model.

EXPERIMENTAL DESIGN

Various bladder cancer cell lines were treated with HTI-286 and mitomycin C (MMC) in vitro. Human KU-7 bladder tumor cells that stably express firefly luciferase were inoculated in female nude mice by intravesical instillation and quantified using bioluminescence imaging. Mice with established KU-7-luc tumors were given HTI-286 or MMC intravesically twice a week for 2 h. Pharmacokinetic data was obtained using high-performance liquid chromatography-mass spectrometry analyses.

RESULTS

In vitro, HTI-286 was a potent inhibitor of proliferation in all tested cell lines and induced marked increases in apoptosis of KU-7-luc cells even after brief exposure. In vivo, HTI-286 significantly delayed cancer growth of bladder tumors in a dose-dependent fashion. HTI-286, at a concentration of 0.2 mg/mL, had comparable strong cytotoxicity as 2.0 mg/mL of MMC. The estimated systemic bioavailability of intravesically given HTI-286 was 1.5% to 2.1% of the initial dose.

CONCLUSIONS

Intravesical HTI-286 instillation therapy showed promising antitumor activity and minimal toxicity in an orthotopic mouse model of high-grade bladder cancer. These findings provide preclinical proof-of-principle for HTI-286 as an intravesical therapy for nonmuscle-invasive bladder cancer and warrant further evaluation of efficacy and safety in early-phase clinical trials.

Bladder cancer angiogenesis and metastasis--translation from murine model to clinical trial

In the majority of cases, death from bladder cancer results from metastatic disease. Understanding the closely linked mechanisms of invasion, metastasis and angiogenesis in bladder cancer has allowed us to develop new therapeutic strategies that harbor the promise of decisive improvements in patient survival. The essential link between cell based experiments and the translation of novel agents into human patients with bladder cancer is the animal model. With emphasis on the orthotopic xenograft model, this review outlines some key mechanisms relevant to angiogenesis and the development of metastasis in bladder cancer. We highlight especially pathways related to MMP-9, IL-8, VEGF and EGFR. Most commonly, expression patterns of these markers in patients have correlated to disease progression and patient survival, which has led to laboratory investigations of these markers and eventually novel targeted therapies that are translated back into the clinic by means of clinical trials. Although imperfect in their translatability into clinical efficacy, animal models remain a critical tool in bladder cancer research.

Newly developed mini-endoscope for diagnosis and follow-up of orthotopic bladder transitional-cell carcinoma in vivo

BACKGROUND AND PURPOSE

Orthotopic models of bladder transitional-cell carcinoma (TCC) are indispensable to the development of new intravesical agents for the treatment of non-muscle-invasive disease. Visual inspection of induced tumors and normal urothelium is of crucial interest when evaluating growth patterns and the potential effects of instillation therapies. The aim of our study was to test the practicability of a newly developed mini-endoscope in terms of the benefit and reproducibility of repeated diagnostic cystoscopy in a rat model, thus mimicking standard procedures in patients.

MATERIALS AND METHODS

The study group consisted of 24 Foxn(rnu) athymic nude rats. In 18 animals, a suspension of the human TCC cell line UMUC-3 was instilled into the urinary bladder after trypsinization. Six animals underwent bladder trypsinization only and served as a control group. Follow-up cystoscopy was performed weekly. A newly developed semirigid mini-endoscope (Karl Storz, Tuttlingen, Germany), 0.89 mm in diameter, was used.

RESULTS

In total, 213 cystoscopies were performed. Each animal underwent at least seven procedures at weekly intervals over a period of 2 months. All tumors were detected by the mini-endoscope within 14 days of tumor-cell implantation. Cystoscopy provided visibility of the entire lower urinary tract (LUT), with the smallest detectable lesion being 0.5 mm in diameter. The regularly performed cystoscopy was tolerated without any significant procedure-related morphologic alterations in the LUT.

CONCLUSIONS

The new mini-endoscope constitutes a practicable and reliable tool for diagnosis and regular follow-up cystoscopy in rats. This instrument can contribute to the preclinical development of experimental intravesical antitumor agents when used for regular evaluations of morphologic drug effects in vivo.

A validated mouse model for orthotopic bladder cancer using transurethral tumour inoculation and bioluminescence imaging

OBJECTIVES

To describe a technique for transurethral tumour inoculation, bioluminescence imaging (BLI) and validation of this approach using ex vivo magnetic resonance imaging (MRI), as a reproducible and quantifiable model of orthotopic bladder cancer is required to enable preclinical pharmacological studies of intravesically administered anticancer agents and the use of BLI provides a sensitive method to monitor tumour growth over time.

MATERIALS AND METHODS

Human KU-7 bladder tumour cells were transduced with a lentiviral construct to stably express the firefly luciferase gene. These cells were then inoculated in female nude mice by intravesical instillation. BLI was performed weekly and the mice were killed after 4 weeks. Ex vivo MRI and whole-mount step-sections were obtained to assess bladder tumour volume.

RESULTS

KU-7 tumour cells were highly tumorigenic and were successfully inoculated in 96% of mice. After 4 weeks, all tumours were confined to the mucosa and submucosa (</=pT1). There was an excellent correlation between tumour volume and BLI for both ex vivo bladder MRI (R(2) = 0.929) and end-point histological measurements (R(2) = 0.836).

CONCLUSIONS

We have established and validated a reliable model of orthotopic bladder cancer that can be used to evaluate various methods of intravesical therapy. BLI allows excellent longitudinal surveillance and quantification of tumour burden.

The use of histone deacetylase inhibitor FK228 and DNA hypomethylation agent 5-azacytidine in human bladder cancer therapy

The long-term disease-free survival in patients with metastatic transitional cell carcinoma (TCC) is still considerably low. Novel chemotherapeutic agents are needed to decrease the morbidity and mortality of TCC. In this study, we have evaluated several epigenetic modifiers for their therapeutic application in bladder cancer. Both histone deacetylase inhibitors (FK228, TSA) and DNA hypomethylating agent (5-Azacytidine) were tested using in vitro assays such as cell viability, cell cycle analysis and western blot to determine their mechanisms of action. Drug combination experiments were also designed to study any additive or synergistic effects of these agents. In addition, two bladder cancer xenograft models (one subcutaneous and one orthotopic) were employed to assess the therapeutic efficacy of these agents in vivo. Three agents exhibited various growth inhibitory effects on 5 different TCC cell lines in a dose- and time-dependent manner. In addition to G2/M cell cycle arrest, FK228 is more potent in inducting apoptosis than the two other single agents, and combination of both FK228 and 5-Aza further enhances this effect. p21 induction is closely associated with FK228 or TSA but not 5-Aza, which is mediated via p53-independent pathway. Consistent with in vitro results, FK228 exhibited a significant in vivo growth inhibition of TCC tumor in both subcutaneous and orthotopic xenograft models. FK228 is a potent chemotherapeutic agent for TCC in vivo with minimal undesirable side effects. The elevated p21 level mediated via p53 independent pathway is a hallmark of FK228 mechanism of action.

Efficacy of a single intravesical treatment with Ad-IFN/Syn 3 is dependent on dose and urine IFN concentration obtained: implications for clinical investigation

There is a need to improve the treatment of superficial bladder cancer. One area which holds promise is intravesical gene therapy. Recently, studies undertaken by us have shown that marked tumor regression of bladder cancers occurred after two daily intravesical administrations of an adenovirus encoding human interferon alpha (Ad-IFNalpha) using a mouse superficial bladder cancer model in which human bladder tumors are growing. A dose of 1 x 10(11) particles/ml (P/ml) was used along with 1 mg/ml of Syn3, a gene transfer-enhancing agent. Since clinical studies are being planned using this approach, it became critical to determine if one exposure and lower particle number could be equally effective. We report that indeed a single dose of Ad-IFNalpha in Syn3 at doses of 1 x 10(10)-1 x 10(11) P/ml is highly effective in reducing the size of the tumors, whereas 1 x 10(9) P/ml was not. Efficacy was also correlated with the level of IFN produced in the urine after treatment. Based on the results of the present studies, a Phase I trial is being planned for superficial bladder cancer, which will involve a single initial treatment with Ad-IFNalpha/Syn3 and measurement of IFN in the urine over time as an indicator of adequate gene transfer and expression.

Dual-track pathway of bladder carcinogenesis: practical implications

CONTEXT

The concept of a dual-track pathway in bladder carcinogenesis postulates that bladder cancer develops via 2 distinct but somewhat overlapping pathways, termed the papillary and nonpapillary. Approximately 80% of bladder carcinomas consist of superficial exophytic papillary lesions that originate from urothelial hyperplasia. These typically low-grade papillary tumors may recur, but they rarely invade the bladder wall or metastasize. The remaining 15% to 20% of tumors represent high-grade solid nonpapillary bladder carcinoma, which arise from high-grade intraurothelial neoplasia. These tumors aggressively invade the bladder wall and have a high propensity for distant metastasis.

OBJECTIVE

To summarize the scientific literature and provide a clinicopathologic review of the dual-track concept of bladder carcinogenesis with its important implications.

DATA SOURCES

Relevant articles indexed in PubMed (National Library of Medicine) between 1974 and 2005.

CONCLUSIONS

Although the characteristics of papillary and nonpapillary tumors are quite dissimilar, current evidence implies that both forms of bladder cancer start as a clinically occult clonal expansion of preneoplastic lesions that occupy large areas of the bladder mucosa.

Intravesical Ad-IFNalpha causes marked regression of human bladder cancer growing orthotopically in nude mice and overcomes resistance to IFN-alpha protein

We have produced prolonged, high local concentrations of interferon in vivo by intravesical instillation of adenoviruses encoding interferon-alpha (Ad-IFNalpha) together with the gene transfer-enhancing agent Syn3. We found sustained interferon protein levels for days, both in normal mouse urothelium and in human bladder cancer cells growing as superficial bladder tumors in nude mice using an orthotopic bladder model developed by us. Tumor burden in the bladder was determined utilizing cancer cells containing the green fluorescent protein. Marked tumor regression was observed following two 1-h exposures of Ad-IFNalpha/Syn3 and little or no cytotoxicity was detected in normal cells. Similar intravesical instillation of clinically relevant concentrations of IFN protein alone or Ad-IFNalpha without Syn3 was ineffective. Surprisingly, in vitro, Ad-IFNalpha also caused caspase-dependent death of bladder cancer cell lines that were resistant to high concentrations of IFN-alpha protein, including the cell line used in vivo. These findings demonstrate that Ad-IFNalpha can overcome resistance to IFN-alpha protein both in vitro and in vivo and support evaluation of intravesical Ad-IFNalpha/Syn3 for the treatment of superficial bladder cancer.

p53 protein transduction therapy: successful targeting and inhibition of the growth of the bladder cancer cells

INTRODUCTION

Virus-mediated gene therapy for bladder cancer has some problems, such as efficiency of gene delivery and safety issues. We have reported that poly-arginine peptide (11R) has the ability to increase protein transduction in cells. Here, we show that p53 protein transduction using 11R is useful for targeting to bladder tumors and suppressing the growth of bladder cancer cells.

MATERIALS AND METHODS

An 11R-fused p53 protein (11R-p53) was transduced in bladder cancer cell lines (J82 and T24) to evaluate the anti-tumor effect. Cell viability was assessed by performing the 4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate (WST) assay. To investigate whether 11R-p53 enhanced the effect on anti-cancer drug-dependent apoptosis of bladder cancer cells, the cell lines were cotreated with 11R-p53 and cis-diaminedichloroplatinum (CDDP). Apoptotic cells were identified using Hoechst staining. To investigate the efficiency of protein transduction mediated by 11R in bladder tumors in vivo, SCID mice were transplanted with J82 cells in the bladder and 11R-GFP was transurethrally transduced into the bladder. The transduction of 11R-GFP in the tumor was examined by confocal microscopy.

RESULTS

11R-p53 inhibited the growth of both J82 and T24 cells in a dose-dependent manner. The transduction of 11R-p53 enhanced CDDP-dependent induction of apoptosis. Transurethral application of 11R-GFP resulted in transduction of GFP in bladder tumors but not in the normal bladder epithelium or subepithelial tissues.

CONCLUSION

The present results suggest that p53 protein transduction therapy may be a promising method for the treatment of bladder cancer.

Application of Targeted Radiotherapy/Gene Therapy to Bladder Cancer Cell Lines

OBJECTIVES

A targeted radiotherapy/gene therapy strategy for transitional cell carcinoma of bladder is described, using [131I]meta-iodobenzylguanidine ([131I]MIBG), a radionuclide combined with a tumour-seeking drug. The aim is to decrease side effects from radiation toxicity, while increasing radiation dose to tumour. This tumour cell kill approach is augmented by radiological bystander effects.

METHODS

The bladder cancer cell line EJ138 was transfected with a gene encoding the noradrenaline transporter (NAT) under the control of tumour-specific telomerase promoters. Resulting uptake of [131I]MIBG was assessed by gamma-counting of cell lysates, and NAT transgene expression by real-time RT-PCR. Cell kill of monolayers and disaggregated spheroids, dosed with [131I]MIBG, was assessed by clonogenic assay.

RESULTS

NAT gene transfected cells exhibited a significantly increased active uptake of [131I]MIBG, leading to dose-dependent cell kill. Clonogenic assay of disaggregated spheroids, a three-dimensional model, suggested cell kill via bystander effects.

CONCLUSIONS

Expression of a functional NAT after in vitro transfection of bladder cancer cells with the NAT gene under the control of telomerase promoters leads to active uptake of [131I]MIBG and dose-dependent cell kill. This strategy could produce a promising new treatment option for bladder cancer.

Replicating Adenoviruses in Cancer Therapy

The potential use of adenoviruses in therapy against cancer has evoked a rapidly moving field of research. Unlike conventional gene therapy vectors, oncolytic adenoviruses retain the ability to replicate. However, replication is restricted as much as possible to tumor cells, with the aim of eliminating these cells through viral cytotoxicity. The two key issues are to improve the efficiency of virus replication and cell killing while ensuring the specificity of these activities for tumor cells. Wild-type adenoviruses as such may already be usable for cancer therapy. Strategies to further improve efficiency and specificity include the partial or complete removal of viral genes. The idea is that functions carried out by the corresponding gene products are not required for replication in tumor cells, but are needed in normal cells. Accordingly, the removal of genes encoding E1B-55 kDa or E1B-19 kDa, or the mutation of E1A may improve the selective killing of tumor cells. On the other hand, the overexpression of the adenovirus death protein (ADP) may enhance viral spread and oncolytic efficiency. Other strategies to improve the specific oncolytic activity of replicating adenoviruses have been pursued. For instance, some promoters are active specifically in tumor cells, and these promoters were introduced into the viral genome, to regulate essential viral genes. Moreover, replicating viruses were engineered to express toxic proteins or drug converters. A number of these viruses have been tested successfully using tumor xenografts in nude mice as a model system. An oncolytic adenovirus lacking the E1B-55 kDa gene product, termed dl1520 or ONYX015, was injected into squamous cell carcinomas of head and neck in phase II clinical trials, and the results were encouraging when chemotherapy was applied in parallel. In the future, further progress might be achieved on the level of virus constructs, but also by refining and adjusting simultaneous conventional therapies, and by standardizing the assessment of the clinical outcome. Recent progress has been made towards the use of replicating virus constructs in cancer therapy. The goal of these developments is to remove cancerous cells from patients with the help of viruses that selectively replicate in these cells. These viruses are generally termed oncolytic viruses. Some convenient properties of adenovirus make this virus particularly useful for this purpose. It infects a large number of human cell types, especially epithelial cells, which give rise to the vast majority of human malignancies. It can be grown easily and to high titers, and the creation of virus recombinants is well established. Finally, a large body of basic research has already been carried out on this virus, facilitating its manipulation. Various approaches to use adenovirus as a cancer drug have been reviewed (Alemany et al. 1999a, 2000; Curiel 2000; Galanis et al. 2001b; Gromeier 2001; Heise and Kirn 2000; Kirn 2000a; Kirn et al. 2001; Kirn and McCormick 1996; Smith and Chiocca 2000; Sunamura 2000; Wells 2000; Wodarz 2001). The aim of this chapter is to provide an integrated overview of these strategies.