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The glnD gene of Gluconacetobacter diazotrophicus was isolated by complementation of the Azotobacter vinelandii glnD (nfrX) mutant strain MV17 using a pLAFR3 cosmid library. The 5 kb chromosomal DNA region encoding the glnD gene on cosmid pAD401 was identified by introduction of deletions as well as subcloning of restriction fragments followed by subsequent DNA sequencing. Three open reading frames were identified with the deduced amino acid sequence of ORF1 showing significant homologies to known GlnD proteins of other proteobacteria such as Sinorhizobium meliloti, Rhizobium tropici, Escherichia coli and Azotobacter vinelandii.A mutagenesis of the chromosomal glnD gene was carried out by insertion of an interposon carrying the kanamycin resistance gene of Tn5. Mutants carrying the cassette inserted into a central region of glnD could not be isolated, while an interposon mutation at the 3′ end of glnD was successful. The resulting strain showed a prolonged generation time in complex growth medium and was unable to utilize ammonium as sole nitrogen source. This phenotype appears to be pleiotropic, since the addition of single amino acids to the minimal medium was not sufficient to allow growth. Furthermore, the glnD mutant was able to express nitrogenase under diazotrophic as well as repressing growth conditions. [Copyright &y& Elsevier]

• Up to 50% of patients undergoing cystectomy are clinically understaged. • Identifying responders to neoadjuvant therapy is vital for bladder preservation. • We need precise definitions of clinical response and associated survival outcomes. • DNA damage response gene alterations are promising predictive markers. The morbidity associated with radical cystectomy (RC) for muscle-invasive bladder cancer (MIBC) has fueled investigations into the feasibility of bladder preservation strategies after a favorable clinical response to neoadjuvant therapy (NAT). Identifying optimal candidates for bladder preservation is predicated on our ability to identify tumors with inherent cisplatin sensitivity and accurately stage patients before and after NAT. In the present review, we evaluate the accuracy and limitations of contemporary staging modalities and investigate clinical outcomes in patients with MIBC who were managed with bladder preservation after NAT. Lastly, we discuss the predictive role of cisplatin-sensitizing DNA damage response (DDR) gene alterations as a foundational component to current prospective clinical trials evaluating bladder preservation in the setting of MIBC. [ABSTRACT FROM AUTHOR]

• The International Bladder Cancer Network (IBCN) celebrates its 25th anniversary. • The IBCN has evolved as a nidus for international, interdisciplinary research. • This Editorial briefly presents the IBCN and its mission. • In addition, 3 major topics in current bladder cancer research are introduced. [ABSTRACT FROM AUTHOR]

In 1997 an international group of scientists organized a meeting in Barcelona, Spain, to discuss the use of biomarkers in the management of patients with bladder cancer. This meeting was the offspring of an - initially informal - group that finally resulted in the foundation and incorporation of the International Bladder Cancer Network (IBCN) e.V. in 2005. Over the years the group has supported several research initiatives and generated several recommendations on the use of biomarkers in the diagnosis and treatment of bladder cancer. Meeting quality was generated by inviting experts presenting state-of-the-art lectures or work in progress reports, interdisciplinarity and the limited number of participants supporting an open and personal exchange resulted in a format increasingly attracting participants from all over the world. The recent limitations caused by the Covid-19 pandemic were partially met by organizing several well attended webinars. The future challenge is to maintain the IBCN meeting spirit despite an increasing interest of the scientific community and industrial partners to participate. However, the integration of and interaction between increasingly more specialized disciplines is a challenge that can be better catalyzed by an international multidisciplinary network than mostly national professional associations. [ABSTRACT FROM AUTHOR]

Abstract: Background: The clinical relevance of polymerase chain reaction (PCR)–based techniques for detection of disseminated tumour cells (DTCs) in the bone marrow of bladder cancer (BCa) patients is still under debate, as data on long-term follow-up analysis have not yet been published. Objective: The aim of the present prospective study was to assess the prognostic significance of DTCs detected by cytokeratin-20 (CK20) reverse-transcriptase PCR in bone marrow from BCa patients undergoing radical cystectomy (RC). Design, setting, and participants: Bone marrow samples from 51 BCa patients with high-risk non–muscle-invasive or muscle-invasive urothelial carcinoma were drawn from the anterior iliac crest prior to RC. CK20-positive cells in bone marrow were detected by qualitative RT-PCR. Measurements: BCa patients with CK20 status were analysed with respect to the end points tumour progression and cancer death. A multivariate Cox regression analysis was performed to determine independent prognostic factors for progression-free survival (PFS), tumour-specific survival (TSS), and overall survival (OS). Results and limitations: CK20-positive cells were detected in 16 of 51 (31.4%) BCa patients of all stages. BCa patients with CK20-negative status displayed a 7-yr PFS rate of 64% versus 35.2% for CK20-positive patients (p =0.007). TSS was significantly shorter in the CK20-positive group, with a 7-yr survival rate of 46.9% compared to CK20-negative patients with 70.2% (p =0.012). The 7-yr OS rate of 37.5% for CK20-positive patients was significantly <65.7% in the CK20-negative group (p =0.006). A subgroup analysis of lymph node–negative patients (pN0) discriminated by CK20 status revealed significant differences in PFS, TSS, and OS. In a multivariate analysis, CK20-status provides independent prognostic information with respect to all three survival end points. Conclusions: BCa patients with positive CK20 status in bone marrow represent a high-risk subgroup reflected by an unfavourable outcome in the long-term analysis. [Copyright &y& Elsevier]

The 16th Meeting of the International Bladder Cancer Network (IBCN) took place from October 11 to 13, 2018 in Rotterdam, the Netherlands. As in the previous year, muscle-invasive bladder cancer (MIBC) was the main topic of the congress based upon the rapid evolution in this field over the last several years. This year´s meeting was dominated by presentations focusing on genomic subtyping in MIBC and identification of novel therapeutic targets. These topics were complemented by submissions on immunotherapy, a variety of clinical topics, and biomarker research. Based upon the presentations, it may be concluded that the IBCN increasingly serves as an interdisciplinary forum not only for the presentation of work-in-progress covering all facets of bladder cancer research, but also for catalyzing the discussion of discrepant research findings in an effort to find consensus. The 16th Meeting of the IBCN took place from October 11 to 13th, 2018 in Rotterdam, the Netherlands, hosted by Ellen Zwarthoff and Joost Boormans. Approximately 120 participants gathered for another fully packed program displaying recent achievements in basic and clinical research covering the entire spectrum of bladder cancer. This year's meeting was dominated by presentations focusing on genomic subtyping and identification of novel therapeutic targets. These topics were complemented by submissions on immunotherapy, clinical topics, and biomarker research. Keynote lectures were delivered by G. Robertson (Canada) on MIBC genomics and the organizational challenges of the PanCancerAtlas project. Comprehensive information was provided on the Cancer Genome Atlas (TCGA) project including the structure of the consortium and the development and validation of molecular classification of MIBC. Results from the project suggest that regulons (groups of genes controlled by a common regulator) appear to be correlated with prognosis and may replace gene expression analysis in the future. M. Thelen (Switzerland) discussed the role of chemokines in cancer metastasization reporting on his research on the atypical chemokine receptor 3. The inaugural IBCN lecture was presented by M. Ingersoll (France) discussing gender disparities in development of adaptive immunity following Bacillus Calmette-Guerin therapy. In addition to the traditional "Industry meets IBCN" sessions, a format for discussion between industry representatives, researchers, and physicians in break-out groups, new formats were introduced-in the Oxford style of debate, P.J. Goebell (Germany) and W. Stadler (USA) delivered animated discussion on the appropriateness of urologists administering systemic immune checkpoint inhibitors. There was consensus that practice may differ between different health systems and countries, and educational/training background. In a second interesting discussion, D. McConkey (USA) and H. Al-Ahmadie (USA) debated if traditional histology will be replaced by molecular classification of bladder tumors. It was concluded that molecular classification offers valuable additional information but cannot yet replace traditional histology. Furthermore, the growing evidence of tumor heterogeneity in bladder cancer was discussed in a separate topic session. L. Dyrskjot discussed genomic and transcriptomic heterogeneity and their impact on clinical decision making. G. Sjödahl presented data on heterogeneity of molecular subtypes within the primary tumor and between the primary tumor and metastases, that is surprisingly limited. Y. Allory discussed spatial and temporal heterogeneity of bladder cancers particularly focusing on the basal-like phenotype. Due to the continued increase in the number of participants and abstract submissions, a poster session was implemented at this year´s meeting for the first time. Posters were briefly presented in the forum. Two travel awards were presented to H. Yamashita (USA) for his submission on peroxisome proliferator-activated receptor gamma-mediated repression of transcription factor activating protein 2 alfa expression identifying a transcriptional circuit in basal-squamous bladder cancer in a cell line model. S.B. Williams (USA) received his award for his registry-based analysis of outcome and costs in patients with localized MIBC undergoing either bladder sparing trimodal therapy or radical cystectomy. The latter was found to generate improved survival outcomes at lower costs as compared with trimodal therapy. The best presentation awards were presented to A. Kamoun (France) who discussed a consensus molecular classification for MIBC. The international demand for a consensus classification, already raised at previous meetings, has resonated with important players in this field. A potential consensus comprising 6 classes was proposed based upon a thorough analysis of the existing classifications. As an extension of the IBCN meeting a consensus conference on genomic classification of MIBC was held that included all major groups in this field. M. Garige (USA) received his award for a detailed examination of inhibitors of metabolic processes in bladder cancer cells before and after therapy. A take home message of the meeting was that the IBCN increasingly serves as an interdisciplinary forum not for the presentation of work-in-progress covering all facets of bladder cancer research, but also for catalyzing the discussion of discrepant research findings in an effort to find consensus. Exemplified may this also be by the fact that the efforts to unify the subclassification of MIBC had its nidus on the preceding meetings of the IBCN on this topic and brought together the various disciplines which ultimately were able to finalize their consensus work in a last concluding meeting directly following the IBCN. Thus, the IBCN meetings and the close cooperation of IBCN with its official journal, Urological Oncology, continue to provide a unique platform for exchange, discussing and intensifying multidimensional collaborations, thus finally satisfying the increasing need for answers regarding the management of bladder cancer patients. The 17th meeting of the IBCN will take place in Aarhus, Denmark, October 3 to 5, 2019. [ABSTRACT FROM AUTHOR]

This editorial highlights submissions to part II of the 3rd IBCN Seminars Series particularly focusing on the tools required for conduction of translational research in bladder cancer. One of the submissions describe the ex vivo culture of primary tumor cells from N-methyl-N-nitrosourea-induced bladder tumors in rats and subsequent establishment of an immortalized cell line. In a next step the authors thoroughly characterize this cell line. They conclude that differentiation marker expression patterns observed in the original tumors are largely retained in the spheroids. Although new cancer models, such as organoid tissue cultures, hold great promise for studying cancer progression and might have a potential for development and selection of an optimal treatment, their limitations must be kept in mind. The second submission, therefore, critically questions the current role of organoid tissue culture as a predictive tool in urothelial cancer patients. The third manuscript of this series provides a broader overview of post-translational modification in bladder cancer is presented and how PTMs can be exploited as potential therapeutic targets. The 3 manuscripts featured in this issue demonstrate especially how basic research is being channeled to inform clinically actionable discoveries. [ABSTRACT FROM AUTHOR]

Background It has been demonstrated that androgen receptor splice variant 7 (AR-V7) expression in circulating tumor cells (CTCs) predicts poor treatment response in metastatic castration-resistant prostate cancer (mCRPC) patients treated with abiraterone or enzalutamide. Objective To develop a practical and robust liquid profiling approach for direct quantification of AR-V7 in peripheral whole blood without the need for CTC capture and to determine its potential for predicting treatment response in mCRPC patients. Design, setting, and participants Whole blood samples from a prospective biorepository of 85 mCRPC patients before treatment initiation with abiraterone ( n = 56) or enzalutamide ( n = 29) were analyzed via droplet digital polymerase chain reaction. Outcome measurements and statistical analysis The association of AR-V7 status with prostate-specific antigen (PSA) response defined by PSA decline ≥50% and with PSA–progression-free survival (PSA-PFS), clinical PFS, and overall survival (OS) was assessed. Results and limitations High AR-V7 expression levels in whole blood were detectable in 18% (15/85) of patients. No patient with high AR-V7 expression achieved a PSA response, and AR-V7 status was an independent predictor of PSA response in multivariable logistic regression analysis ( p = 0.03). High AR-V7 expression was associated with shorter PSA-PFS (median 2.4 vs 3.7 mo; p < 0.001), shorter clinical PFS (median 2.7 vs 5.5 mo; p < 0.001), and shorter OS (median 4.0 vs. 13.9 mo; p < 0.001). On multivariable Cox regression analysis, high AR-V7 expression remained an independent predictor of shorter PSA-PFS (hazard ratio [HR] 7.0, 95% confidence interval [CI] 2.3–20.7; p < 0.001), shorter clinical PFS (HR 2.3, 95% CI 1.1–4.9; p = 0.02), and shorter OS (HR 3.0, 95% CI 1.4–6.3; p = 0.005). Conclusions Testing of AR-V7 mRNA levels in whole blood is a simple and promising approach to predict poor treatment outcome in mCRPC patients receiving abiraterone or enzalutamide. Patient summary We established a method for determining AR-V7 status in whole blood. This test predicted treatment resistance in patients with metastatic castration-resistant prostate cancer undergoing treatment with abiraterone or enzalutamide. Prospective validation is needed before application to clinical practice. [ABSTRACT FROM AUTHOR]

Background: Progression of non-muscle-invasive bladder cancer (NMIBC) to muscle-invasive bladder cancer (MIBC) is life-threatening and cannot be accurately predicted using clinical and pathological risk factors. Biomarkers for stratifying patients to treatment and surveillance are greatly needed. Objective: To validate a previously developed 12-gene progression score to predict progression to MIBC in a large, multicentre, prospective study. Design, setting, and participants: We enrolled 1224 patients in ten European centres between 2008 and 2012. A total of 750 patients (851 tumours) fulfilled the inclusion and sample quality criteria for testing. Patients were followed for an average of 28 mo (range 0-76). A 12-gene real-time qualitative polymerase chain reaction assay was performed for all tumours and progression scores were calculated using a predefined formula and cut-off values. Outcome measurements and statistical analysis: We measured progression to MIBC using Cox regression analysis and log-rank tests for comparing survival distributions. Results and limitations: The progression score was significantly (p < 0.001) associated with age, stage, grade, carcinoma in situ, bacillus Calmette-Guérin treatment, European Organisation for Research and Treatment of Cancer risk score, and disease progression. Univariate Cox regression analysis showed that patients molecularly classified as high risk experienced more frequent disease progression (hazard ratio 5.08, 95% confidence interval 2.2-11.6; p < 0.001). Multivariable Cox regression models showed that the progression score added independent prognostic information beyond clinical and histopathological risk factors (p < 0.001), with an increase in concordance statistic from 0.82 to 0.86. The progression score showed high correlation (R² = 0.85) between paired fresh-frozen and formalin-fixed paraffin-embedded tumour specimens, supporting translation potential in the standard clinical setting. A limitation was the relatively low progression rate (5%, 37/750 patients). Conclusions: The 12-gene progression score had independent prognostic power beyond clinical and histopathological risk factors, and may help in stratifying NMIBC patients to optimise treatment and follow-up regimens. Patient summary: Clinical use of a 12-gene molecular test for disease aggressiveness may help in stratifying patients with non-muscle-invasive bladder cancer to optimal treatment regimens. [ABSTRACT FROM AUTHOR]

• Identification of CDK4/6 inhibitor downstream targets that confer therapy response. • Palbociclib in combination with KIF1C inhibitors act synergistically. • Combination of ciprofloxacin and palbociclib act synergistic on bladder cancer. CDK4/6 inhibitors have proven their potency for the treatment of cancer but only in combination with hormone or targeted therapies. The aim of this study was the identification of molecules that are involved in response mechanisms to CDK4/6 inhibitors and the development of novel combination therapies with corresponding inhibitors in bladder cancer. Genes of response to therapy and genes that confer resistance to the CDK4/6 inhibitor palbociclib were identified by performing an analysis of published literature and own published data using a CRISPR-dCas9 genome wide gain of function screen. Genes that were down-regulated upon treatment were compared with genes that confer resistance when up-regulated. Two of the top 5 genes were validated by quantitative PCR and western blotting upon treatment with palbociclib in the bladder cancer cell lines T24, RT112 and UMUC3. As inhibitors for combination therapy, we used ciprofloxacin, paprotrain, ispinesib and SR31527. Analysis of synergy was done using the "zero interaction potency" model. Cell growth was examined using sulforhodamine B staining. A list of genes that met the requirements for inclusion in the study was generated from 7 publications. Of the 5 most relevant genes, MCM6 and KIFC1 were chosen and their down-regulation upon treatment with palbociclib was confirmed by qPCR and immunoblotting. The combination of inhibitors against both, KIFC1 and MCM6 with PD resulted in a synergistic inhibition of cell growth. We have identified 2 molecular targets whose inhibition has promising potential for effective combination therapies with the CDK4/6 inhibitor palbociclib. [ABSTRACT FROM AUTHOR]

Background: To determine the anatomic extent of pelvic lymph node dissection (PLND) in prostate cancer (PCa) patients at the time of radical prostatectomy (RP), knowledge about the topography of lymph node (LN) metastases is required. Objective: Because small-volume LN metastases may be missed by standard histopathologic examination, we performed an anatomic mapping study combining molecular and histopathologic LN examination in PCa patients treated with RP and extended PLND (ePLND). Design, setting, and participants: A total of 52 patients with intermediate- (n = 15) and high-risk (n = 37) PCa underwent RP and ePLND without neoadjuvant treatment. ePLND included dissection of the obturator fossa and the external, internal, and common iliac vessels. Outcome measurements and statistical analysis: LNs ≥3 mm in diameter were analysed by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) for prostate-specific antigen (PSA) expression and by standard histopathology. Topography of positive LNs was determined descriptively. Results and limitations: Of 1469 dissected LNs (median: 27 LNs per patient), 1186 LNs were ≥3 mm. Molecular LN analysis was positive in 127 LNs of 27 patients (52%) including 32 LNs of 12 patients (23%) with histopathologic positive LNs. Molecular examination was negative in 3 of 35 histopathologic positive LNs (9%). Combining both molecular and histopathologic findings, positive LNs were located in the standard PLND field defined by obturator fossa and external iliac vessels in 71%, along the internal iliac vessels in 16%, and along the common iliac vessels in 13%. Of LN-positive patients, 63% had LN metastases outside the standard PLND field. The internal iliac field was involved in 48% and the common iliac field in 37% of node-positive patients. Notably, internal and common iliac vessels were the only positive regions in 7% and 11% of node-positive patients, respectively. A limitation is the small number of patients included. Conclusions: These findings underline the enhanced sensitivity of qRT-PCR in comparison with standard histopathology for detection of small-volume LN metastases in PCa patients. Our results support an ePLND including the common iliac vessels, at least up to the ureteral crossing, to optimise nodal staging and to remove LNs potentially harbouring metastases. [ABSTRACT FROM AUTHOR]

Abstract: Objective: Novel strategies for the treatment of advanced prostate cancer (CaP), including immunotherapy or gene therapy, are currently under evaluation with Sipuleucel-T as first FDA-approved immunotherapeutic. Here, we examine cytosine-phosphorothioate-guanine (CpG)-DNA oligonucleotides (ODN) to boost cytokine responses and costimulatory molecule expression on murine bone marrow-derived dendritic cells (mBMDC). Furthermore, we evaluate the potency of a PSA-peptide based vaccine in combination with CpG-DNA to elicit specific cytotoxic T cell (CTL) responses. Materials and methods: mBMDC were stimulated with CpG-DNA (1668: 5′-TCCATGACGTTCCTGATGCT-3′) or non-stimulatory control-ODN (1720: 5′-TCCATGAGC TTCCTGATGCT-3′). Subsequently, expression of the costimulatory molecules CD40 and CD86 and induction of proinflammatory cytokines (interleukin (IL)-6 and IL-12) were analyzed. For induction of PSA-peptide specific CTL, female C57BL/6 mice were immunized with PSA-peptide 65–73 (HCIRNKSVI) alone or in combination with 1668 or 1720-ODN. In vivo cytotoxicity assay determined PSA-peptide specific cytotoxicity 1 week after vaccination. Results: Treatment of mBMDC with stimulatory CpG-DNA ODN resulted in pronounced up-regulation of costimulatory molecule expression on mBMDC in a dose-dependent manner. CpG-ODN significantly increased production of IL-6 and IL-12 in mBMDC (P < 0.001). Induction of PSA-peptide specific CTL responses in mice immunized with PSA-peptide and CpG-DNA were significantly greater than those of PSA-peptide and control-ODN immunized mice or PSA-peptide only vaccination. Conclusions: CpG-DNA acts as potent adjuvant for vaccination therapies and elicits profound PSA-peptide specific CTL responses in combination with an immunodominant PSA-peptide. CpG-ODN mediated immunotherapy represents a potentially inexpensive, safe, easy-to-produce, and easy-to-handle treatment alternative. Therefore, further evaluation of CpG-DNA in immunization therapies against CaP is warranted. [Copyright &y& Elsevier]

Objective: Presence of lymph node (LN) metastasis in bladder cancer (BCa) is a main risk factor for tumor recurrence after radical cystectomy (RC). Molecular analysis facilitates detection of small-volume LN metastases with higher sensitivity than standard histopathology. The aim of the present study was to establish molecular LN analysis in BCa patients undergoing RC with lymph node dissection (LND) and to determine its ability to predict tumor recurrence.Patients and Methods: Five transcripts with overexpression in BCa (FXYD3, KRT17, KRT20, SPINK1, UPKII) were evaluated for molecular LN analysis. We included 76 BCa patients from the prospective, randomized surgical phase-III trial (LEA AUO AB 25/02, NCT01215071) investigating extended vs. limited LND at RC. The primary endpoint was recurrence-free survival (RFS). As control, 136 LNs from 45 patients without BCa were analyzed to determine a threshold for pathologic gene expression.Results: About 1,319 LNs were investigated with molecular and histopathologic examination. Histopathology detected 39 LN metastases in 17 (22%) patients. Of the tested genes FXYD3 performed best and classified all pN+-patients correctly as node-positive (pN+/molN+). In addition, FXYD3 reclassified 43 histopathologic negative LNs and 7 (9%) pN0-patients as molecular node-positive (pN0/molN+). Molecular and histopathologic LN status (pN0/molN0 vs. pN0/molN+ vs. pN+/molN+) was significantly associated with locally advanced disease (P = 0.006) and poor RFS (P < 0.001). Median RFS was not reached in LN-negative patients (pN0/molN0), 45 months (95%CI 8-83) in exclusively molecular positive patients (pN0/molN+) and 9 months (95%CI 5-13) in patients with histopathologic and molecular positive LNs (pN+/molN+).Conclusions: Molecular LN analysis with FXYD3 identified additional LN metastases in histopathologic negative LNs and identified patients with elevated risk of tumor recurrence after RC. Thus, molecular LN analysis improves LN staging and might serve as a tool to guide adjuvant treatment. [ABSTRACT FROM AUTHOR]

Purpose: To analyze the contribution of Wnt signaling pathway to bladder cancer growth in order to identify suitable target molecules for therapy.Material and Methods: Expression of Wnt 2/4/7, LRP5/6, TCF1/2/4, LEF-1, and β-actin was detected by reverse transcription polymerase chain reaction in a panel of 9 and for Wntless (WLS) in 17 bladder cancer cell lines. Protein expression of WLS was detected in 6 cell lines. Wnt/β-catenin activity was analyzed using the TOPflash/FOPflash luciferase reporter assay. Expression level of β-catenin, WIF1, Dickkopf proteins (DKK), HSulf-2, sFRP4, and WLS was modulated by transfecting or infecting cells transiently or stably with respective shRNAs, siRNAs, or cDNAs. For protein detection, whole cell lysates were applied to sodium dodecyl sulfate polyacrylamide gel electrophoresis followed by immunoblots. Effects on cell growth were determined by cell viability assays and BrdU/APC incorporation/staining. For 3-dimensional tumor growth, the chicken chorioallantoic membrane model was used. Tumor growth was characterized by weight.Results: Expression of molecular components and activation of the Wnt signaling pathway could be detected in all cell lines. Expression level of β-catenin, WIF1, DKK, WLS, and HSulf-2 influenced Wnt activity. Expression of WLS was confirmed in 17 cell lines by reverse transcription polymerase chain reaction and in 6 cell lines by immunoblotting. WLS positively regulates Wnt signaling, cell proliferation, and tumor growth in vitro and in vivo. These effects could be reversed by the expression of the Wnt antagonist WIF1 and DKK. Synergistic activity of cisplatin and WLS inactivation by genetic silencing could be observed on cell viability.Conclusion: The Wnt signaling pathway is ubiquitously activated in bladder cancer and regulates tumor growth. WLS might be a target protein for novel therapies in combination with established chemotherapy regimens. [ABSTRACT FROM AUTHOR]

Background: Rapid development of novel treatment options demands valid preclinical screening models for urothelial carcinoma (UC). The translational value of high-throughput drug testing using 2-dimensional (2D) cultures is limited while for xenograft models handling efforts and costs often become prohibitive for larger-scale drug testing. Therefore, we investigated to which extent the chicken chorioallantoic membrane (CAM) assay might provide an alternative model to study antineoplastic treatment approaches for UC.Methods: The ability of 8 human UC cell lines (UCCs) to form tumors after implantation on CAMs was investigated. Epithelial-like RT-112 and mesenchymal-like T-24 UCCs in cell culture or as CAM tumors were treated with cisplatin alone or combined with histone deacetylase inhibitors (HDACi) romidepsin and suberanilohydroxamic acid. Tumor weight, size, and bioluminescence activity were monitored; tumor specimens were analyzed by histology and immunohistochemistry. Western blotting and quantitative real time polymerase chain reaction were used to measure protein and mRNA expression.Results: UCCs were reliably implantable on the CAM, but tumor development varied among cell lines. Expression of differentiation markers (E-cadherin, vimentin, CK5, CK18, and CK20) was similar in CAM tumors and 2D cultures. Cellular phenotypes also remained stable after recultivation of CAM tumors in 2D cultures. Bioluminescence images correlated with tumor weight. Cisplatin and HDACi decreased weight and growth of CAM tumors in a dose-dependent manner, but HDACi treatment acted less efficiently as in 2D cultures, especially on its typically associated molecular markers. Synergistic effects of HDACi and subsequent cisplatin treatment on UCCs were neither detected in 2D cultures nor detected in CAM tumors.Conclusion: Our results demonstrate that the CAM assay is a useful tool for studying tumor growth and response to conventional anticancer drugs under 3D conditions, especially cytotoxic drugs as cisplatin. With some limitations, it might serve as a cost- and time-effective preclinical screening assay for novel therapeutic approaches before further assessment in expensive and cumbersome animal models. [ABSTRACT FROM AUTHOR]