Cadherin switching dictates the biology of transitional cell carcinoma of the bladder: ex vivo and in vitro studies

Phases of tight junction barrier disruption during transurothelial migration of invasive urothelial cancer cells

Bladder cancer is characterised by its multifocal nature and a high recurrence, yet the underlying mechanisms of these phenomena remain only partially understood. In the present study, we aimed to investigate transurothelial invasion of urothelial cancer cells as a potential mechanism for dissemination of bladder cancer and to identify the key molecules involved in urothelial barrier disruption. Using confocal and electron microscopy, we were able to show that within a 24-hour timeframe muscle-invasive urothelial cancer cells T24 adhere to the partially differentiated normal urothelial in vitro model and initially cause localised disruption of the tight junctions between urothelial cells. Subsequently, urothelial cells separate and individual T24 cells migrate paracellularly through the urothelium. qPCR analysis identified fibroblast activation protein (FAP)/seprase as the candidate most likely to be involved in urothelial barrier disruption. In addition, treatment of T24 cells with Pefabloc resulted in the inhibition of T24 cell invasion. Our results contribute to the understanding of the mechanisms underlying transurothelial invasion of urothelial cancer cells. Among the molecules tested, FAP/sepraseis likely involved in cancer cell-induced disruption of the urothelial barrier, suggesting its potential as a therapeutic target to prevent progression and recurrence of bladder cancer.

Precise identification of bladder tumors utilizing mucoadhesive thiolated hollow mesoporous silica nanoparticles

Non-muscle invasive bladder cancer (NMIBC) poses significant challenges due to its high recurrence rates and the difficulty in accurately distinguishing tumor lesions. Effective and economical methods for identifying cancerous tissues are urgently needed. In this study, we employed thiolated hollow mesoporous silica nanoparticles loaded with Evans blue (EB@HMSN(E)-SH), a traditional tumor staining dye, in conjunction with white light cystoscopy (WLC) to enhance the detection of bladder tumors. We observed that EB@HMSN(E)-SH exhibited mucoadhesive properties, demonstrating significant aggregation upon interaction with mucin, as assessed by the mucin-particle method using Dynamic Light Scattering (DLS). The permeation-enhancing capability of EB@HMSN(E)-SH was evaluated using tumor spheroid models. Despite repeated flushing, EB@HMSN(E)-SH adhered effectively to the mice bladder mucosa, aiding in the differentiation of tumor tissue from normal and inflammatory lesions, facilitated by the disordered structure of tumor tissue. Tissues stained with EB@HMSN(E)-SH showed co-localization with NBT-2 tumor cells expressing GFP, confirmed by confocal microscopy, which revealed deeper penetration of EB released from HMSN(E)-SH into bladder tumors compared to free EB. The combined use of WLC and EB@HMSN(E)-SH enabled precise identification of tumor-like tissues, corroborated by histopathological examination using H&E staining. The mucoadhesive properties and extended retention time of EB@HMSN(E)-SH complement WLC effectively in identifying NMIBC, suggesting its potential as a promising diagnostic tool.

Identification of epithelial-related artificial neural network prognostic models for the prediction of bladder cancer prognosis through comprehensive analysis of single-cell and bulk RNA sequencing

Background

Bladder cancer (BLCA) presents as a heterogeneous epithelial malignancy. Progress in the early detection and effective treatment of BLCA relies heavily on the identification of novel biomarkers. Therefore, the primary goal of this study is to pinpoint potential biomarkers for BLCA through the fusion of single-cell RNA sequencing and RNA sequencing assessments. Furthermore, the aim is to establish practical clinical prognostic models that can facilitate accurate categorization and individualized therapy for patients.

Methods

In this research, training sets were acquired from the TCGA database, whereas validation sets (GSE32894) and single-cell datasets (GSE135337) were extracted from the GEO database. Single-cell analysis was utilized to obtain characteristic subpopulations along with their associated marker genes. Subsequently, a novel BLCA subtype was identified within TCGA-BLCA. Furthermore, an artificial neural network prognostic model was constructed within the TCGA-BLCA cohort and subsequently verified utilizing a validation set. Two machine learning algorithms were employed to screen hub genes. QRT-qPCR was performed to detect the gene expression levels utilized in the construction of prognostic models across various cell lines. Additionally, the cMAP database and molecular docking were utilized for searching small molecule drugs.

Results

The results of single-cell analysis revealed the presence of epithelial cells in multiple subpopulations, with 1579 marker genes selected for subsequent investigations. Subsequently, four epithelial cell subtypes were identified within the TCGA-BLCA cohort. Notably, cluster A exhibited a significant survival advantage. Concurrently, an artificial neural network prognostic model comprising 17 feature genes was constructed, accurately stratifying patient risk. Patients categorized in the low-risk group demonstrated a considerable survival advantage. The ROC analysis suggested that the model has strong prognostic ability. Furthermore, the findings of the validation group align consistently with those from the training group. Two types of machine learning algorithms screened NFIC as hub genes. Forskolin, a small molecule drug that binds to NFIC, was identified by employing a cMAP database and molecular docking.

Conclusion

The analysis results supplement the research on the role of epithelial cells in BLCA. An artificial neural network prognostic model containing 17 characteristic genes demonstrates the capability to accurately stratify patient risk, thereby potentially improving clinical decision-making and optimizing personalized therapeutic approaches.

Prognostic significance of E-Cadherin and B-Catenin in non-muscle invasive bladder cancer

Non muscle invasive bladder cancer (NMIBC) has unpredictable outcomes with a variable risk of recurrence and progression. Many clinic-pathological prognostic factors have been identified but remain insufficient, raising the need to investigate new biomarkers. The aim of our study was to assess the prognostic value of the immunohistochemical (IHC) markers E-Cadherin and B-Catenin in NMIBC. All cases of NMIBC were collected between 2008 and 2013. IHC analysis was performed using E-Cadherin and B-Catenin. Reduced or loss of E-Cadherin expression was assessed as abnormal. Only cases with B-Catenin intense membranous staining were considered normal. A correlation was found between abnormal E-Cadherin expression and stage (p = 0.001), grade (p = 0.0000000), recurrence (p = 0.0000000), progression (p = 0.01), recurrence-free survival (p = 0.00000001), and progression-free survival (p = 0.01). A statistically significant association was found between B-Catenin and stage (p = 0. 05), grade (p = 0.02), and recurrence (p = 0.02). The abnormal expression of these markers could help to identify a high-risk subgroup of NMIBC that might benefit from either more accurate follow-up or more aggressive treatment.

Cytosolic Cadherin 4 promotes angiogenesis and metastasis in papillary thyroid cancer by suppressing the ubiquitination/degradation of β-catenin

BACKGROUND

Although the long-term prognosis of papillary thyroid cancer (PTC) is favorable, distant metastasis significantly compromises the prognosis and quality of life for patients with PTC. The Cadherin family plays a pivotal role in tumor metastasis; however, the involvement of Cadherin 4 (CDH4) in the metastatic cascade remains elusive.

METHODS

The expression and subcellular localization of CDH4 were determined through immunohistochemistry, immunofluorescence, and western blot analyses. The impact of CDH4 on cell migration, invasion, angiogenesis, and metastasis was assessed using transwell assays, tube formation assays, and animal experiments. Immunoprecipitation assay and mass spectrometry were employed to examine protein associations. The influence of CDH4 on the subcellular expression of β-catenin and active β-catenin was investigated via western blotting and immunofluorescence. Protein stability and ubiquitination assay were employed to verify the impact of CDH4 on β-catenin degradation. Rescue experiments were performed to ensure the significance of CDH4 in regulating nuclear β-catenin signaling.

RESULTS

CDH4 was found to be significantly overexpressed in PTC tissues and predominantly localized in the cytoplasm. Furthermore, the overexpression of CDH4 in tumor tissues is associated with lymph node metastasis in PTC patients. Cytosolic CDH4 promoted the migration, invasion, and lung metastasis of PTC cells and stimulated the angiogenesis and tumorigenesis of PTC; however, this effect could be reversed by Tegavivint, an antagonist of β-catenin. Mechanistically, cytosolic CDH4 disrupted the interaction between β-catenin and β-TrCP1, consequently impeding the ubiquitination process of β-catenin and activating the nuclear β-catenin signaling.

CONCLUSIONS

CDH4 induces PTC angiogenesis and metastasis via the inhibition of β-TrCP1-dependent ubiquitination of β-Catenin.

Chronic Arsenic Exposure Upregulates the Expression of Basal Transcriptional Factors and Increases Invasiveness of the Non-Muscle Invasive Papillary Bladder Cancer Line RT4

The bladder is a target organ for inorganic arsenic, a carcinogen and common environmental contaminant found in soil and water. Urothelial carcinoma (UC) is the most common type of bladder cancer (BC) that develops into papillary or non-papillary tumors. Papillary tumors are mostly non-muscle invasive (NMIUC), easier treated, and have a better prognosis. Urothelial carcinoma can be molecularly sub-typed as luminal or basal, with papillary tumors generally falling into the luminal category and basal tumors exclusively forming muscle invasive urothelial carcinomas (MIUC). It is unclear why some UCs develop more aggressive basal phenotypes. We hypothesized that chronic arsenic exposure of a papillary luminal bladder cancer would lead to the development of basal characteristics and increase in invasiveness. We treated the human papillary bladder cancer cell line RT4 with 1 µM arsenite (As³⁺) for twenty passages. Throughout the study, key luminal and basal gene/protein markers in the exposed cells were evaluated and at passage twenty, the cells were injected into athymic mice to evaluate tumor histology and measure protein markers using immunohistochemistry. Our data indicates that chronic As³⁺- treatment altered cellular morphology and decreased several luminal markers in cell culture. The histology of the tumors generated from the As³⁺-exposed cells was similar to the parent (non-treated) however, they appeared to be more invasive in the liver and displayed elevated levels of some basal markers. Our study demonstrates that chronic As³⁺ exposure is able to convert a non-invasive papillary bladder cancer to an invasive form that acquires some basal characteristics.

Dual role of E-cadherin in cancer cells

E-cadherin is the main component of epithelial adherens junctions (AJs), which play a crucial role in the maintenance of stable cell-cell adhesion and overall tissue integrity. Down-regulation of E-cadherin expression has been found in many carcinomas, and loss of E-cadherin is generally associated with poor prognosis in patients. During the last decade, however, numerous studies have shown that E-cadherin is essential for several aspects of cancer cell biology that contribute to cancer progression, most importantly, active cell migration. In this review, we summarize the available data about the input of E-cadherin in cancer progression, focusing on the latest advances in the research of the various roles E-cadherin-based AJs play in cancer cell dissemination. The review also touches upon the "cadherin switching" in cancer cells where N- or P-cadherin replace or are co-expressed with E-cadherin and its influence on the migratory properties of cancer cells.

Lobular Breast Cancer: Histomorphology and Different Concepts of a Special Spectrum of Tumors

Simple Summary

Invasive lobular breast cancer (ILC) is a special type of breast cancer (BC) that was first described in 1941. The diagnosis of ILC is made by microscopy of tumor specimens, which reveals a distinct morphology. This review recapitulates the developments in the microscopic assessment of ILC from 1941 until today. We discuss different concepts of ILC, provide an overview on ILC variants, and highlight advances which have contributed to a better understanding of ILC as a special histologic spectrum of tumors.

Abstract

Invasive lobular breast cancer (ILC) is the most common special histological type of breast cancer (BC). This review recapitulates developments in the histomorphologic assessment of ILC from its beginnings with the seminal work of Foote and Stewart, which was published in 1941, until today. We discuss different concepts of ILC and their implications. These concepts include (i) BC arising from mammary lobules, (ii) BC growing in dissociated cells and single files, and (iii) BC defined as a morpho-molecular spectrum of tumors with distinct histological and molecular characteristics related to impaired cell adhesion. This review also provides a comprehensive overview of ILC variants, their histomorphology, and differential diagnosis. Furthermore, this review highlights recent advances which have contributed to a better understanding of the histomorphology of ILC, such as the role of the basal lamina component laminin, the molecular specificities of triple-negative ILC, and E-cadherin to P-cadherin expression switching as the molecular determinant of tubular elements in CDH1-deficient ILC. Last but not least, we provide a detailed account of the tumor microenvironment in ILC, including tumor infiltrating lymphocyte (TIL) levels, which are comparatively low in ILC compared to other BCs, but correlate with clinical outcome. The distinct histomorphology of ILC clearly reflects a special tumor biology. In the clinic, special treatment strategies have been established for triple-negative, HER2-positive, and ER-positive BC. Treatment specialization for patients diagnosed with ILC is just in its beginnings. Accordingly, ILC deserves greater attention as a special tumor entity in BC diagnostics, patient care, and cancer research.

Trends in urine biomarker discovery for urothelial bladder cancer: DNA, RNA, or protein?

Urothelial bladder cancer is a complex disease displaying a landscape of heterogenous molecular subtypes, mutation profiles and clinical presentations. Diagnosis and surveillance rely on flexible cystoscopy which has high accuracy, albeit accompanied by a high-cost burden for healthcare providers and discomfort for patients. Advances in "omic" technologies and computational biology have provided insights into the molecular pathogenesis of bladder cancer and provided powerful tools to identify markers for disease detection, risk stratification, and predicting responses to therapy. To date, numerous attempts have been made to discover and validate diagnostic biomarkers that could be deployed as an adjunct to the cystoscopic diagnosis and long-term surveillance of bladder cancer. We report a comprehensive literature analysis using PubMed to assess the changing trends in investigating DNA, RNA, or proteins as diagnostic urinary biomarkers over a period of 5 decades: 1970-2020. A gradual shift has been observed in research away from protein biomarkers to nucleic acids including different classes of RNA, and DNA methylation and mutation markers. Until 2000, publications involving protein biomarker discovery constituted 87% of the total number of research articles with DNA comprising 6% and RNA 7%. Since 2000 the proportion of protein biomarker articles has fallen to 40%, and DNA and RNA studies increased to 32% and 28%, respectively. Clearly research focus, perhaps driven by technological innovation, has shifted from proteins to nucleic acids. We optimistically hypothesise that, following thorough validation, a clinically useful detection test for bladder cancer based on a panel of DNA or RNA markers could become reality within 5-10 years.

Ephrin-B1 Is a Novel Biomarker of Bladder Cancer Aggressiveness. Studies in Murine Models and in Human Samples

Bladder cancer (BC) is the ninth most common cancer worldwide, but molecular changes are still under study. During tumor progression, Epithelial cadherin (E-cadherin) expression is altered and β-catenin may be translocated to the nucleus, where it acts as co-transcription factor of tumor invasion associated genes. This investigation further characterizes E-cadherin and β-catenin associated changes in BC, by combining bioinformatics, an experimental murine cell model (MB49/MB49-I) and human BC samples. In in silico studies, a DisGeNET (gene-disease associations database) analysis identified CDH1 (E-cadherin gene) as one with highest score among 130 BC related-genes. COSMIC mutation analysis revealed CDH1 low mutations rates. Compared to MB49 control BC cells, MB49-I invasive cells showed decreased E-cadherin expression, E- to P-cadherin switch, higher β-catenin nuclear signal and lower cytoplasmic p-Ser33-β-catenin signal, higher Ephrin-B1 ligand and EphB2 receptor expression, higher Phospho-Stat3 and Urokinase-type Plasminogen Activator (UPA), and UPA receptor expression. MB49-I cells transfected with Ephrin-B1 siRNA showed lower migratory and invasive capacity than control cells (scramble siRNA). By immunohistochemistry, orthotopic MB49-I tumors had lower E-cadherin, increased nuclear β-catenin, lower pSer33-β-catenin cytoplasmic signal, and higher Ephrin-B1 expression than MB49 tumors. Similar changes were found in human BC tumors, and 83% of infiltrating tumors depicted a high Ephrin-B1 stain. An association between higher Ephrin-B1 expression and higher stage and tumor grade was found. No association was found between abnormal E-cadherin signal, Ephrin-B1 expression or clinical-pathological parameter. This study thoroughly analyzed E-cadherin and associated changes in BC, and reports Ephrin-B1 as a new marker of tumor aggressiveness.

E-cadherin to P-cadherin switching in lobular breast cancer with tubular elements

Loss of E-cadherin expression due to mutation of the CDH1 gene is a characteristic feature of invasive lobular breast cancer (ILBC). Beta-catenin, which binds to the cytoplasmic domain of E-cadherin, is simultaneously downregulated, reflecting disassembly of adherens junctions (AJs) and loss of cell adhesion. E-cadherin to P-cadherin expression switching can rescue AJs and cell adhesion. However, P-cadherin has not been implicated in ILBC, so far. We aimed to characterize 13 ILBCs with exceptional histomorphology, which we termed ILBCs with tubular elements. The CDH1 mutational status was determined by next generation sequencing and whole-genome copy number (CN) profiling. Expression of cadherins was assessed by immunohistochemistry. ILBCs with tubular elements were ER-positive (13/13) and HER2-negative (13/13) and harbored deleterious CDH1 mutations (11/13) accompanied by loss of heterozygosity due to deletion of chromosome 16q22.1 (9/11). E-cadherin expression was lost or reduced in noncohesive tumor cells and in admixed tubular elements (13/13). Beta-catenin expression was lost in noncohesive tumor cells, but was retained in tubular elements (11/13), indicating focal rescue of AJ formation. N-cadherin and R-cadherin were always negative (0/13). Strikingly, P-cadherin was commonly positive (12/13) and immunoreactivity was accentuated in tubular elements. Adjacent lobular carcinoma in situ (LCIS) was always P-cadherin-negative (0/7). In a reference cohort of LCIS specimens, P-cadherin was constantly not expressed (0/25). In a reference cohort of invasive mammary carcinomas, P-cadherin-positive cases (36/268, 13%) were associated with triple-negative nonlobular breast cancer (P < 0.001). Compared with ILBCs from the reference cohort, P-cadherin expression was more common in ILBCs with tubular elements (12/13 versus 7/84, P < 0.001). In summary, E-cadherin to P-cadherin switching occurs in a subset of ILBCs. P-cadherin is the molecular determinant of a mixed-appearing histomorphology in ILBCs with tubular elements.

Relationship between SDC1 and cadherin signalling activation in cancer

E-cadherin and SDC1 are markers of epithelial-to-mesenchymal transition (EMT) that can be used to assess tumour prognosis. SDC1 has different effects in various types of cancers. On the one hand, reduced expression of SDC1 can leads to advantage stages of some cancers, such as gastric and colorectal cancer. On the other hand, SDC1 overexpression can also promote the growth and proliferation of cancer cells in pancreatic and breast cancer. However, the function of SDC1 is influenced and regulated by many factors. Exfoliated extracellular domain HS chain can mediate the function of SDC1 and play an important role in the occurrence and development of cancer. SDC1 binds to various ligands and influences the growth and reproduction of cancer cells via the activation of Wnt, the long isoform of FLICE-inhibitory protein (FLIP long), vascular endothelial growth factor receptor (VEGFR), mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) and MAPK/c-Jun N-terminal kinase (JNK) and other pathways. Cadherins occur in several types, but this review focuses on classical cadherins. N-cadherin and P-cadherin are activated during tumour development, whereas E-cadherin is a tumour suppressor. The cellular signalling pathways involved in classical cadherins, such as Wnt and VEGFR pathways, are also related to SDC1. The activation of E-cadherin caused by SDC1 knockdown has also been observed. Despite this evidence, no articles regarding the relationship of SDC1 and cadherin activation have been published. This review summarises the expressions of these two molecules in different cancers and analyses their possible relationship to provide insights into future cancer research and clinical treatment.

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.

Effects of multi and selective targeted tyrosine kinase inhibitors on function and signaling of different bladder cancer cells

BACKGROUND

Signaling of receptor tyrosine kinases (RTK) is dysregulated in various malignancies including bladder cancer. RTKs trigger pro-proliferative, anti-apoptotic and metastatic signaling pathways. Here, we assessed the effects of a selective tyrosine kinase inhibitor (TKI) (BGJ398) targeting fibroblast growth factor receptor (FGFR) and a pan-TKI (TKI258) targeting (FGFR), platelet derived growth factor receptor (PDGFR) and vascular endothelial growth factor receptor (VEGFR) in bladder cancer cells.

METHODS

Levels of mRNA transcripts were measured in nine human cell lines by quantitative RT-PCR. Cell function was assessed for viability, colony formation, migration, apoptosis and proliferation. Protein mediators of signal transduction were measured by Western-blot.

RESULTS

mRNA transcripts encoding RTK-related components, transcription factors, epithelial and mesenchymal transition (EMT) markers as well as cell cycle and apoptotic factors were determined in the cell lines. Principal component analysis ordered one epithelial-like cell cluster (5637, BFTC-905, MGHU4, RT112) and one mesenchymal-like cell cluster (T24, UMUC3, HU456, TCC-SUP). Cell response scores towards TKI258 and BGJ398 treatment were heterogeneous between cell lines and correlated with certain transcript levels. Analysis of signal transduction pathways revealed inhibition of fibroblast growth factor receptor (FGFR) signaling and induction of cell cycle dependent kinase (CDKN1A, p21) in epithelial-like cells differing in this regard from responses to mesenchymal-like cells that exhibited inhibition of mitogen-activated protein kinase (MAPK).

CONCLUSION

RTK and EMT related transcript analysis separate bladder cancer cells in two clusters. Functional responses towards TKI258 and BGJ398 treatment of bladder Fcancer cells were heterogeneous with deviating effects on signaling and possibly different therapeutic outcome.

P-Cadherin (CDH3) is overexpressed in colorectal tumors and has potential as a serum marker for colorectal cancer monitoring

Introduction

Placental-Cadherin (CDH3) is a cell adhesion molecule vital to cellular localization and tissue integrity. It is highly expressed in the placenta (PLC)and is overexpressed by many types of cancer. P-cadherin levels in colorectal cancer (CRC) remains poorly characterized. This study's purpose was to determine P-cadherin expression in CRC and normal tissues and to assess plasma CDH3 levels in order to determine the relationship, if any, between cancer stage, P-cadherin expression and plasma CDH3 levels.

Methods

An IRB approved plasma, tumor, and prospective data bank was utilized. CRC patients for whom tumor and normal colon tissue samples were available were enrolled. Tumor samples were OCT embedded and stored at -80C°. Total purified RNA was isolated from tissue samples and cDNA synthesized. CDH3 expression was analyzed by quantitative PCR (QPCR) using the SYBR Green platform. Tumor expression levels were determined and compared to levels in normal colonic tissue and PLC. Expression in 22 different normal tissues was also assessed by RT-PCR. Plasma CDH3 levels were determined via ELISA in patients for whom preoperative blood samples were available. Results: A total of 77 paired CRC and normal colon specimens (36 M/ 41 F, age 67.3±14.5) were assessed (82% colon, 18% rectal; Cancer Stage 2, 44; Stage 3, 33). All tested tumors had CDH3 expression levels over 0.1% of the PLC level and tumor to normal colon ratios greater than 1. CDH3 expression was noted in 14/22 normal organ tissues. There was a positive correlation between tumor CDH3 QPCR and preoperative CDH3 blood levels (n=57, P= 0.038). Expression levels were significantly higher in rectal vs. colon tumors (p=0.019). Conclusion: CDH3 expression was elevated in CRC tumors as compared to normal tissue. CDH3 was expressed by numerous normal organs and, thus, is not a viable vaccine target, however, the correlation between plasma and tumor CDH3 levels suggests CDH3 may have value as a diagnostic or prognostic marker.

PAK5 mediates cell: cell adhesion integrity via interaction with E-cadherin in bladder cancer cells

Urothelial bladder cancer is a major cause of morbidity and mortality worldwide, causing an estimated 150 000 deaths per year. Whilst non-muscle-invasive bladder tumours can be effectively treated, with high survival rates, many tumours recur, and some will progress to muscle-invasive disease with a much poorer long-term prognosis. Thus, there is a pressing need to understand the molecular transitions occurring within the progression of bladder cancer to an invasive disease. Tumour invasion is often associated with a down-regulation of E-cadherin expression concomitant with a suppression of cell:cell junctions, and decreased levels of E-cadherin expression have been reported in higher grade urothelial bladder tumours. We find that expression of E-cadherin in a panel of bladder cancer cell lines correlated with the presence of cell:cell junctions and the level of PAK5 expression. Interestingly, exogenous PAK5 has recently been described to be associated with cell:cell junctions and we now find that endogenous PAK5 is localised to cell junctions and interacts with an E-cadherin complex. Moreover, depletion of PAK5 expression significantly reduced junctional integrity. These data suggest a role for PAK5 in maintaining junctional stability and we find that, in both our own patient samples and a commercially available dataset, PAK5mRNA levels are reduced in human bladder cancer compared with normal controls. Taken together, the present study proposes that PAK5 expression levels could be used as a novel prognostic marker for bladder cancer progression.

Evans blue-mediated white-light detection of non-muscle-invasive bladder cancer: A preclinical feasibility and safety study using a rat bladder urothelial cell carcinoma model

Photodynamic diagnosis (PDD) improves the detection of non-muscle-invasive bladder cancer (NMIBC). However, white-light (WL) cystoscopy remains the technique routinely used in urological clinics. A more cost-effective but equally performant alternative to PDD may encompass the use of an intense tumoritropic dye in combination with WL cystoscopy. Using a preclinical setting, we investigated the practical aspects of the use of Evans blue (EB) dye for the possible future detection of NMIBC using WL cystoscopy. A solution of 1 and 5 mM EB was instilled into healthy and AY-27 tumor-bearing rat bladders. The bladders were then rapidly dissected and the inner walls were inspected for EB using WL stereomicroscopy. EB present in the bladders and the plasma was also quantified using high performance liquid chromatography. To assess the effects of repeated instillations on normal rat bladders, EB was instilled for 7 consecutive days, after which time the bladder wall was investigated histologically. To gain insight into the mechanisms underlying the selective accumulation of EB in malignant urothelium, RNA sequencing of urothelial tissue and subsequent comparative analysis were performed, with a specific focus on cell adhesion. The concentrations of EB were substantially higher in malignant bladders compared with those in healthy bladders, matching the blue staining of the inner bladder wall observed by stereomicroscopy. EB was equally present in the plasma of healthy and tumor-bearing subjects, although at low concentrations. Importantly, EB did not cause any abnormalities in the urothelium after 7 days of repeated instillation in normal rats. RNA sequencing of the urothelium indicated an abnormal expression of several genes related to cell adhesion in malignant urothelium compared with the normal urothelium. Our findings may be important for future clinical developments in the field of diagnostics for bladder cancer. Implementing the more cost-effective protocol of EB instillations in combination with WL cystoscopy may offer a benefit to patients as well as the healthcare system.

WHO 1973 grade 3 and infiltrative growth pattern proved, aberrant E-cadherin expression tends to be of predictive value for progression in a series of stage T1 high-grade bladder cancer after organ-sparing approach

PURPOSE

Stage pT1 urothelial bladder cancer (UBC) is characterized as a challenging subentity of urothelial carcinoma with an unforeseeable clinical course. In addition to more or less established clinical and histopathological features, we evaluated the role of epithelial-mesenchymal transition (EMT) marker E-cadherin, shown to be of prognostic value in muscle-invasive disease, regarding the prognosis of stage pT1 high-grade (hg) UBC.

METHODS

Tissue of 226 stage pT1 hg UBC patients from transurethral resection could be immunostained for E-cadherin. Kaplan-Meier analysis and univariate and multivariate Cox regression analyses regarding progression-free (PFS) and cancer-specific survival (CSS) were performed.

RESULTS

Aberrant expression of E-cadherin was recognized in 74% of patients. Kaplan-Meier analysis showed that aberrant E-cadherin expression was associated with worse 10-year PFS (62 vs. 90%, p = 0.045). In univariate analysis, aberrant E-cadherin staining, associated carcinoma in situ, grading 3 after WHO classification 1973 and infiltrative growth pattern at the invasion front were the statistically significant predictive factors for worse PFS, only infiltrative growth pattern for CSS. With regard to progression, grading 3 after WHO classification of 1973 (HR 6.49; CI 1.54-27.28, p = 0.011) and infiltrative tumor invasion pattern (HR 2.06; CI 1.10-3.86, p = 0.024) revealed as independent factors for PFS, and there was a trend also for E-cadherin expression (HR 0.45; CI 0.19-1.06; p = 0.068). Regarding CSS, infiltrative tumor growth pattern (HR 3.79; CI 1.67-8.60, p = 0.001) was the only statistically significantly independent predictive factor in multivariate Cox regression analysis.

CONCLUSIONS

Beside invasion growth pattern and WHO grading 1973 that achieved to be independent prognostic factors, there was a trend for the parameter E-cadherin expression to be of predictive value for PFS in stage pT1 hg urothelial bladder carcinoma after organ-sparing approach. Further studies on genetic level are warranted to define the distinct role of EMT in early-invasive UBC.

Association of epithelial-mesenchymal transition and nuclear cofilin with advanced urothelial cancer

Tumor epithelial cells undergo a morphologic shift through the process of EMT with characteristic loss of cell polarity, conferring invasive and metastatic properties during cancer progression. Signaling by transforming growth factor-β mediates EMT programming and its phenotypic reversal to mesenchymal-epithelial transition. The role of EMT in bladder cancer progression to advanced disease is poorly understood. In this study, we conducted a retrospective analysis of the EMT landscape and actin cytoskeleton remodeling in a series of human bladder cancer specimens. Immunoreactivity for E-cadherin, N-cadherin, and vimentin protein expression was performed toward establishing an EMT signature in human bladder cancer. Serial sections were assessed for the primary regulator of the actin cytoskeleton remodeling and transforming growth factor-β signaling effector, cofilin. Our results demonstrate that EMT induction in clinical bladder cancer specimens is significantly associated with bladder cancer progression to high-grade, invasive disease. Evaluation of expression and cellular localization of the cytoskeleton regulator cofilin revealed a significant association between overexpression of nuclear cofilin with bladder cancer progression. This study is of translational significance in defining the value of EMT signature and cytoskeletal cofilin as potential tumor markers and targetable platforms for the treatment of invasive bladder cancer.

Characteristics of bladder transitional cell carcinoma with E-cadherin and N-cadherin double-negative expression

The aim of the present study was to examine the characteristics of bladder transitional cell carcinoma with E-cadherin and N-cadherin double-negative expression. An immunofluorescence assay was used to detect E-cadherin and N-cadherin expression in infiltrative bladder cancer tissues, and immunofluorescence and western blot analysis were used to detect E-cadherin and N-cadherin expression in human urinary bladder grade II carcinoma 5637, transitional cell carcinoma UMUC-3 and invasive bladder carcinoma EJ cells. Cell proliferation, migration, invasion and plate colony formation assays were used to detect the proliferative, migratory and invasive abilities and the efficiency of plate colony formation of 5637, UMUC3 and EJ cells. A tumor xenograft formation assay was used to evaluate the tumorigenic abilities of 5637, UMUC-3 and EJ cells in vivo. E-cadherin and N-cadherin double-negative expression was identified in various pathological grades of infiltrative bladder cancers. E-cadherin positive and N-cadherin negative expression was exhibited by 5637 cells. By contrast, E-cadherin negative and N-cadherin positive expression was exhibited by EJ cells, and E-cadherin and N-cadherin double-negative expression was exhibited by UMUC-3 cells. The ability of cells to proliferate, migrate, invade, and the efficiency of plate colony formation and tumorigenic abilities of the cells were significantly different among 5637, UMUC-3 and EJ cells. These cell characteristics were significantly increased in UMUC-3 cells compared with 5637 cells; however, the characteristics were significantly decreased compared with EJ cells. The biological characteristics of bladder cancer cells with E-cadherin and N-cadherin double-negative expression was between bladder cancer cells that exhibited a E-cadherin positive and N-cadherin negative expression, and bladder cancer cells that exhibited E-cadherin negative and N-cadherin positive expression. The present study deduces that the status of E-cadherin and N-cadherin double-negative expression may participate in the process of epithelial-mesenchymal transition in the pathogenesis of bladder urothelial carcinoma.

Prognostic role of decreased E-cadherin expression in patients with upper tract urothelial carcinoma: a multi-institutional study

PURPOSE

To assess the role of E-cadherin as prognostic biomarker in upper tract urothelial carcinoma (UTUC) in a large multi-institutional cohort of patients.

METHODS

Immunohistochemistry technique was used to evaluate E-cadherin expression in 678 patients with unilateral, sporadic UTUC treated with RNU. E-cadherin expression was considered decreased if 10 % or more cells had decreased expression (<90 %).

RESULTS

Decreased E-cadherin expression was observed in 353 patients (52.1 %) and was associated with advanced pathological stage (P < 0.001), higher grade (P < 0.001), lymph node metastasis (P = 0.006), lymphovascular invasion (P < 0.001), concomitant carcinoma in situ (P < 0.001), multifocality (P = 0.004), tumor necrosis (P = 0.020) and sessile architecture (P < 0.001). Within a median follow-up of 30 months (interquartile range 15-57), 171 patients (25.4 %) experienced disease recurrence and 150 (21.9 %) died from UTUC. In univariable analyses, decreased E-cadherin expression was significantly associated with worse recurrence-free survival (P < 0.001) and cancer-specific survival CSS (P = 0.006); however, in multivariable analyses, it was not (P = 0.74 and 0.84, respectively). The lack of independent prognostic value of E-cadherin remained true in all subgroup analyses.

CONCLUSION

In UTUC patients treated with RNU, decreased E-cadherin expression is associated with features of biologically and clinically aggressive disease and worse outcome in univariable, but not multivariable, analyses. If E-cadherin's association with factors of advanced disease is confirmed on UTUC biopsy specimens, it could be used to help in the clinical decision-making regarding kidney-sparing approaches and/or neo-adjuvant chemotherapy.

Cell adhesion and urothelial bladder cancer: the role of cadherin switching and related phenomena

Cadherins are mediators of cell-cell adhesion in epithelial tissues. E-cadherin is a known tumour suppressor and plays a central role in suppressing the invasive phenotype of cancer cells. However, the abnormal expression of N- and P-cadherin ('cadherin switching', CS) has been shown to promote a more invasive and m̀alignant phenotype of cancer, with P-cadherin possibly acting as a key mediator of invasion and metastasis in bladder cancer. Cadherins are also implicated in numerous signalling events related to embryonic development, tissue morphogenesis and homeostasis. It is these wide ranging effects and the serious implications of CS that make the cadherin cell adhesion molecules and their related pathways strong candidate targets for the inhibition of cancer progression, including bladder cancer. This review focuses on CS in the context of bladder cancer and in particular the switch to P-cadherin expression, and discusses other related molecules and phenomena, including EpCAM and the development of the cancer stem cell phenotype.

Epithelial-mesenchymal transformation markers E-cadherin and survivin predict progression of stage pTa urothelial bladder carcinoma

PURPOSE

To determine whether the immunohistochemical markers survivin and E-cadherin can predict progress at initially diagnosed Ta bladder cancer.

METHODS

We retrospectively searched for every initially diagnosed pTa urothelial bladder carcinoma having been treated at our single-center hospital in Germany from January 1992 up to December 2004. Follow-up was recorded up to June 2010, with recurrence or progress being the endpoints. Immunohistochemical staining and analysis of survivin and E-cadherin of the TURB specimens were performed. Outcome dependency of progression and no progression with immunohistochemical staining was analyzed using uni- and multivariate regression analysis, Kaplan-Meier analysis and uni- and multivariate Cox regression analysis.

RESULTS

Overall, 233 patients were included. Forty-two percent of those were tumor free in their follow-up TURBs, 46 % had at least one pTa recurrence and 12 % even showed progress to at least pT1 bladder cancer. Aberrant staining of E-cadherin was found within 71 % of patients with progression in contrast to only 40 % in cases without progression (p = 0.004). Of all progressed patients, 92 % showed overexpression of survivin in their initial pTa specimen compared to 61 % without progression (p = 0.001). Kaplan-Meier analysis revealed aberrant E-cadherin staining to be associated with worse progression-free survival (PFS) (p = 0.005) as well as overexpression of survivin (p = 0.003). In multivariate Cox regression analysis, strong E-cadherin staining was an independent prognosticator for better PFS (p = 0.033) and multifocality (p = 0.046) and tumor size over 3 cm (p = 0.042) were prognosticators for worse PFS.

CONCLUSION

Adding the immunohistochemical markers survivin and E-cadherin could help to identify patients at risk of developing a progressive disease in initial stage pTa bladder cancer.

Significance of P-cadherin overexpression and possible mechanism of its regulation in intrahepatic cholangiocarcinoma and pancreatic cancer

It has become evident that P-cadherin, one of the classical cadherins, contributes to the malignant behavior of several types of cancer. In this study, we analyzed the expression of P-cadherin and its clinicopathological and prognostic values in intrahepatic cholangiocarcinoma (ICC) and pancreatic cancer. Furthermore, we investigated the functional role of P-cadherin in these cancer cells by knockdown and overexpression in vitro and by analyzing the correlation between the P-cadherin expression and its promoter methylation status. Thirty of 59 ICC cases (51%) and 36 of 73 pancreatic cancer cases (49%) stained positive for P-cadherin with mainly membranous distribution in tumor cells by immunohistochemistry. P-cadherin expression was significantly correlated with several clinicopathological factors, which reflect tumor behavior, and was identified as an independent adverse prognostic factor for disease-free survival in patients with ICC (relative risk [RR] 2.93, P = 0.04) and pancreatic cancer (RR 2.68, P = 0.005) via multivariate analyses. P-cadherin downregulation by siRNA suppressed migration and invasion, and P-cadherin overexpression induced the opposite effects in both ICC and pancreatic cancer cells, without any effects on cell proliferation. P-cadherin expression was related to its promoter methylation status in both cell lines and cancer tissues. In summary, P-cadherin overexpression may serve as a useful biomarker of invasive phenotype and poor prognosis; P-cadherin expression was found to be regulated by its promoter methylation. These results suggest that P-cadherin represents a novel therapeutic target for the treatment of ICC and pancreatic cancer.

HPV-16 E6/E7 promotes cell migration and invasion in cervical cancer via regulating cadherin switch in vitro and in vivo

PURPOSE

Cadherin switch, as a key hallmark of epithelial-mesenchymal transition (EMT), is characterized by reduced E-cadherin expression and increased N-cadherin or P-cadherin expression, and has been implicated in many aggressive tumors, but the importance and regulatory mechanism of cadherin switch in cervical cancer have not been investigated. Our study aimed to explore the role of cadherin switch by regulation of HPV-16 E6/E7 in progression and metastasis of cervical cancer.

METHODS

The expressions of E-cadherin and P-cadherin were examined by immunohistochemical staining in 40 cases of high-grade cervical lesions with HPV-16 infection only in which HPV-16 E6 and E7 expression had been detected using qRT-PCR method. Through modulating E6 and E7 expression using HPV-16 E6/E7 promoter-targeting siRNAs or expressed vector in vitro, cell growth, migration, and invasion were separately tested by MTT, wound-healing and transwell invasion assays, as well as the expressions of these cadherins by western blot analyses. Finally, the expressions of these cadherins in cancerous tissues of BALB/c-nu mouse model inoculated with the stable HPV-16 E6/E7 gene silencing Siha and Caski cells were also measured by immunohistochemical staining.

RESULTS

Pearson correlation coefficient analyses showed the strongly inverse correlation of E-cadherin expression and strongly positive correlation of P-cadherin expression with E6/E7 level in 40 cases of high-grade cervical lesions. Furthermore, the modulation of HPV-16 E6/E7 expression remarkably influenced cell proliferation, migration, and invasion, as well as the protein levels of E-cadherin and P-cadherin in cervical cell lines. Finally, the reduction of HPV-16 E6/E7 expression led to up-regulated expression of E-cadherin and down-regulated expression of P-cadherin in BALB/c-nu mouse model in vivo assay.

CONCLUSIONS

Our results unraveled the possibility that HPV-16 E6/E7 could promote cell invasive potential via regulating cadherin switching, and consequently contribute to progression and metastasis of cervical cancer.

Biodistribution of Evans blue in an orthotopic AY-27 rat bladder urothelial cell carcinoma model: implication for the improved diagnosis of non-muscle-invasive bladder cancer (NMIBC) using dye-guided white-light cystoscopy

OBJECTIVES

To investigate the possibility of using Evans blue (EB) as a novel diagnostic tool to detect bladder tumours with white-light (WL) cystoscopy, in this preclinical study we examine the biodistribution of EB in the different layers (urothelium, submucosa, muscle) of a normal rat bladder and a rat bladder bearing a malignant urothelium composed of syngeneic AY-27 tumour cells.

MATERIALS AND METHODS

EB was instilled into both normal as well as tumour-bearing rat bladders. After instillation, bladders were removed and snap frozen in liquid nitrogen. The distribution of EB in the different layers was quantified using fluorescence microscopy. To gain more insight into the mechanism underlying the selective accumulation of EB in tumour tissue, bladder sections were prepared for ultrastructural investigations by means of transmission electron microscopy (TEM). In addition, we also examined the expression of E-cadherin, claudin-1 and desmoglein-1 by immunohistochemistry to study the integrity of the bladder wall, as these molecules are key constituents of adherens junctions, tight junctions and desmosomes, respectively.

RESULTS

In most cases, the accumulation of EB in malignant bladders was substantially higher than in healthy bladders, at least when 1 mm EB instillations were used. In case of a 1 mm EB instillation for 2 h, the EB-associated fluorescence in malignant urothelial tissue was 55-times higher than the fluorescence found in normal urothelium. Ultrastructurally, malignant tissue displayed wider intercellular spaces and a decreased number of cell junction components compared with normal tissue, pointing to defects in the urothelial barrier. There were no differences in the expression of E-cadherin, whereas desmoglein-1 staining was stronger in the membranes of healthy bladder urothelium compared with tumour tissue. Claudin-1 expression was negative in all samples tested.

CONCLUSION

EB is selectively taken up by tumour tissue after intravesical instillations in rats bearing bladder tumours. The lower expression of desmoglein-1 in tumour samples, together with the reduced presence of desmosomes seen with TEM, likely imply that desmosomes play an important role in the ultrastructural differences between healthy rat urothelium and tumour tissue, and secondary to that, to the differential uptake of EB in both tissues. We consider that our findings could be useful for future clinical developments in the field of diagnostics for bladder cancer.

Breast cancer patient stratification using a molecular regularized consensus clustering method

Breast cancers are highly heterogeneous with different subtypes that lead to different clinical outcomes including prognosis, response to treatment and chances of recurrence and metastasis. An important task in personalized medicine is to determine the subtype for a breast cancer patient in order to provide the most effective treatment. In order to achieve this goal, integrative genomics approach has been developed recently with multiple modalities of large datasets ranging from genotypes to multiple levels of phenotypes. A major challenge in integrative genomics is how to effectively integrate multiple modalities of data to stratify the breast cancer patients. Consensus clustering algorithms have often been adopted for this purpose. However, existing consensus clustering algorithms are not suitable for the situation of integrating clustering results obtained from a mixture of numerical data and categorical data. In this work, we present a mathematical formulation for integrative clustering of multiple-source data including both numerical and categorical data to resolve the above issue. Specifically, we formulate the problem as a novel consensus clustering method called Molecular Regularized Consensus Patient Stratification (MRCPS) based on an optimization process with regularization. Unlike the traditional consensus clustering methods, MRCPS can automatically and spontaneously cluster both numerical and categorical data with any option of similarity metrics. We apply this new method by applying it on the TCGA breast cancer datasets and evaluate using both statistical criteria and clinical relevance on predicting prognosis. The result demonstrates the superiority of this method in terms of effectiveness of aggregation and differentiating patient outcomes. Our method, while motivated by the breast cancer research, is nevertheless universal for integrative genomics studies.

The prognostic value of P-cadherin in non-muscle-invasive bladder cancer

OBJECTIVES

This research aims to specify the prognostic value of P-cadherin on recurrence and progression in non-muscle-invasive bladder cancers (NMIBC).

METHODS

A total of 110 NMIBC cases were collected and P-cadherin protein was assessed by immunohistochemical test in these samples. Correlations between P-cadherin expression and clinicopathologic features were analyzed. For recurrence-free and progression-free survival, Kaplan-Meier log-rank test was used. Then Cox univariate and multivariate analyses were further performed.

RESULTS

P-cadherin high expression correlated with tumor progression (P = 0.031). Kaplan-Meier results showed that patients with high P-cadherin expression had worse progression-free survival (P = 0.034) but not recurrence-free survival (P = 0.133) than low-expression patients. Cox regression results showed P-cadherin expression was an independent predictor for progression (P = 0.042) but not recurrence (P = 0.139) in NMIBC.

CONCLUSIONS

Our results demonstrated that P-cadherin expression correlated with tumor progression and could be taken as an independent predictor for progression in NMIBC.

Epithelial mesenchymal transition status is associated with anti-cancer responses towards receptor tyrosine-kinase inhibition by dovitinib in human bladder cancer cells

Background

Dovitinib (TKI-258) is a receptor tyrosine kinase (RTK) inhibitor targeting fibroblast growth factor receptor (FGFR) and further related RTKs. TKI-258 is under investigation as anticancer drug for the treatment of various cancers including bladder cancer with aberrant RTK signaling. Here, we analyzed the responses of ten human bladder cancer cell lines towards TKI-258 treatment in relation to the epithelial mesenchymal transition (EMT) status of the cells.

Methods

Expression of epithelial marker E-cadherin as well as mesenchymal markers N-cadherin and vimentin was determined by quantitative RT-PCR and Western-blot in RNA and protein extracts from the cultured cell lines. The cell responses were analyzed upon addition of TKI-258 by viability/proliferation (XTT assay) and colony formation assay for measurement of cell contact independent growth.

Results

The investigated bladder cancer cell lines turned out to display quite different EMT patterns as indicated by the abundance of E-cadherin or N-cadherin and vimentin. Protein and mRNA levels of the respective components strongly correlated. Based on E-cadherin and N-cadherin mRNA levels that were expressed approximately mutual exclusively, an EMT-score was calculated for each cell line. A high EMT-score indicated mesenchymal-like cells and a low EMT-score epithelial-like cells. Then, we determined the IC₅₀ values for TKI-258 by dose response curves (0-12 μM TKI-258) in XTT assays for each cell line. Also, we measured the clonogenic survival fraction after adding TKI-258 (1 μM) by colony formation assay. We observed significant correlations between EMT-score and IC₅₀ values (r = 0.637, p = 0.0474) and between EMT-score and clonogenic survival fraction (r = 0.635, p = 0.0483) as analyzed by linear regression analyses.

Conclusions

In sum, we demonstrated that the EMT status based on E-cadherin and N-cadherin mRNA levels may be useful to predict responses towards TKI-258 treatment in bladder cancer.

Modeling the mechanics of cancer: effect of changes in cellular and extra-cellular mechanical properties

Malignant transformation, though primarily driven by genetic mutations in cells, is also accompanied by specific changes in cellular and extra-cellular mechanical properties such as stiffness and adhesivity. As the transformed cells grow into tumors, they interact with their surroundings via physical contacts and the application of forces. These forces can lead to changes in the mechanical regulation of cell fate based on the mechanical properties of the cells and their surrounding environment. A comprehensive understanding of cancer progression requires the study of how specific changes in mechanical properties influences collective cell behavior during tumor growth and metastasis. Here we review some key results from computational models describing the effect of changes in cellular and extra-cellular mechanical properties and identify mechanistic pathways for cancer progression that can be targeted for the prediction, treatment, and prevention of cancer.

Epithelial plasticity, cancer stem cells, and the tumor-supportive stroma in bladder carcinoma

High recurrence rates and poor survival rates of metastatic bladder cancer emphasize the need for a drug that can prevent and/or treat bladder cancer progression and metastasis formation. Accumulating evidence suggests that cancer stem/progenitor cells are involved in tumor relapse and therapy resistance in urothelial carcinoma. These cells seem less affected by the antiproliferative therapies, as they are largely quiescent, have an increased DNA damage response, reside in difficult-to-reach, protective cancer stem cell niches and express ABC transporters that can efflux drugs from the cells. Recent studies have shown that epithelial-to-mesenchymal transition (EMT), a process in which sessile, epithelial cells switch to a motile, mesenchymal phenotype may render cancer cells with cancer stem cells properties and/or stimulate the expansion of this malignant cellular subpopulation. As cancer cells undergo EMT, invasiveness, drug resistance, angiogenesis, and metastatic ability seem to increase in parallel, thus giving rise to a more aggressive tumor type. Furthermore, the tumor microenvironment (tumor-associated stromal cells, extracellular matrix) plays a key role in tumorigenesis, tumor progression, and metastasis formation. Taken together, the secret for more effective cancer therapies might lie in developing and combining therapeutic strategies that also target cancer stem/progenitor cells and create an inhospitable microenvironment for highly malignant bladder cancer cells. This review will focus on the current concepts about the role of cancer stem cells, epithelial plasticity, and the supportive stroma in bladder carcinoma. The potential implications for the development of novel bladder cancer therapy will be discussed.

Epithelial E- and P-cadherins: role and clinical significance in cancer

E-cadherin and P-cadherin are major contributors to cell-cell adhesion in epithelial tissues, playing pivotal roles in important morphogenetic and differentiation processes during development, and in maintaining integrity and homeostasis in adult tissues. It is now generally accepted that alterations in these two molecules are observed during tumour progression of most carcinomas. Genetic or epigenetic alterations in E- and P-cadherin-encoding genes (CDH1 and CDH3, respectively), or alterations in their proteins expression, often result in tissue disorder, cellular de-differentiation, increased invasiveness of tumour cells and ultimately in metastasis. In this review, we will discuss the major properties of E- and P-cadherin molecules, its regulation in normal tissue, and their alterations and role in cancer, with a specific focus on gastric and breast cancer models.

Loss of the urothelial differentiation marker FOXA1 is associated with high grade, late stage bladder cancer and increased tumor proliferation

Approximately 50% of patients with muscle-invasive bladder cancer (MIBC) develop metastatic disease, which is almost invariably lethal. However, our understanding of pathways that drive aggressive behavior of MIBC is incomplete. Members of the FOXA subfamily of transcription factors are implicated in normal urogenital development and urologic malignancies. FOXA proteins are implicated in normal urothelial differentiation, but their role in bladder cancer is unknown. We examined FOXA expression in commonly used in vitro models of bladder cancer and in human bladder cancer specimens, and used a novel in vivo tissue recombination system to determine the functional significance of FOXA1 expression in bladder cancer. Logistic regression analysis showed decreased FOXA1 expression is associated with increasing tumor stage (p<0.001), and loss of FOXA1 is associated with high histologic grade (p<0.001). Also, we found that bladder urothelium that has undergone keratinizing squamous metaplasia, a precursor to the development of squamous cell carcinoma (SCC) exhibited loss of FOXA1 expression. Furthermore, 81% of cases of SCC of the bladder were negative for FOXA1 staining compared to only 40% of urothelial cell carcinomas. In addition, we showed that a subpopulation of FOXA1 negative urothelial tumor cells are highly proliferative. Knockdown of FOXA1 in RT4 bladder cancer cells resulted in increased expression of UPK1B, UPK2, UPK3A, and UPK3B, decreased E-cadherin expression and significantly increased cell proliferation, while overexpression of FOXA1 in T24 cells increased E-cadherin expression and significantly decreased cell growth and invasion. In vivo recombination of bladder cancer cells engineered to exhibit reduced FOXA1 expression with embryonic rat bladder mesenchyme and subsequent renal capsule engraftment resulted in enhanced tumor proliferation. These findings provide the first evidence linking loss of FOXA1 expression with histological subtypes of MIBC and urothelial cell proliferation, and suggest an important role for FOXA1 in the malignant phenotype of MIBC.

Slug contributes to cadherin switch and malignant progression in muscle-invasive bladder cancer development

OBJECTIVES

The Snail family of zinc finger transcription factors (i.e., Snail and Slug) predicts the tumor recurrence in superficial bladder cancers, while their roles in the development of muscle-invasion, metastasis, and chemoresistance in muscle-invasive bladder cancers with poor prognosis have not been investigated. This study evaluates the clinical significance of Slug in aggressive bladder cancer.

MATERIALS AND METHODS

A pair of sublines (i.e., T24-P and T24-L) from a unique orthotropic metastatic model of bladder cancer was firstly utilized to identify the potential precursors contributing to those aggressive phenotypes. The coexpression of Slug, E-cadherin, and N-cadherin in bladder cancer cell lines (i.e., 5637, RT4, 253 J, J82, and T24) and tissues was evaluated by reverse transcription-polymerase chain reaction (RT-PCR), Western blotting, and immunohistochemistry staining analysis. The function of Slug expression on E- to N-cadherin switch, cell invasion, and chemoresistance to proapoptotic treatment was validated by gain-in-function and knockdown strategy in vitro.

RESULTS

Slug was identified as one of the novel targets contributed to the aggressive phenotypes of T24-L cells, which showed enhanced cell invasive, metastatic, and chemoresistant potentials in vitro and in vivo as previously described. Up-regulation of Slug was significantly correlated with a higher tumor stage and the E- to N-cadherin switch in bladder cancer cells and tissues, whereas ectopic expression of Slug in bladder cancer 5637 and RT-4 cell lines promoted epithelial-to-mesenchymal transition (EMT), increased cell invasiveness and chemoresistance. By contrast, knocking down Slug using siRNA in T24-L cell lines reversed these changes.

CONCLUSIONS

Slug elevates in invasive or metastatic bladder cancer and plays a critical role in EMT via control of cadherin switch. Slug may be a potential marker or target for improving the diagnosis and treatment of muscle-invasive bladder cancers.

Biological characteristics of a cell subpopulation in tongue squamous cell carcinoma

OBJECTIVES

To isolate the CD133+CD44+ cells from human tongue squamous cell carcinoma (TSCC) Tca8113 cell line and investigate biological characteristics of them.

MATERIALS AND METHODS

Immunomagnetic microbeads were applied to sort the CD133+CD44+ cells. Flow cytometry was used to detect isolation purity. The proliferation, clone-formation efficiencies, invasion and migration, gene expressions, and tumor-formation abilities were analyzed among CD133+CD44+, CD133-CD44-, and total population of cells.

RESULTS

The average purities of CD133+ and CD44+ cells reached 97.3% and 98.7%, respectively. The proliferation of CD133+CD44+ cells was significantly higher than the other two groups. The clone-forming efficiency of three groups was 70%, 8%, and 14%, respectively. The average invaded and migrated cell numbers of CD133+CD44+ and total population cells were 132 and 36.2, 311.6, and 156.2, respectively. The expressions of Bcl-2 and Sox2 in CD133+CD44+ cells were significantly higher than those in total population cells. A total of 10(4) CD133+CD44+ cells could form secondary tumors in nude mice, while the total population group needed 10(6) cells.

CONCLUSIONS

The CD133+CD44+ subpopulation cells possess stem-like characteristics. They appear to be the potential targets for future biology therapy of human TSCC.

Pathobiology and chemoprevention of bladder cancer

Our understanding of the pathogenesis of bladder cancer has improved considerably over the past decade. Translating these novel pathobiological discoveries into therapies, prevention, or strategies to manage patients who are suspected to have or who have been diagnosed with bladder cancer is the ultimate goal. In particular, the chemoprevention of bladder cancer development is important, since urothelial cancer frequently recurs, even if the primary cancer is completely removed. The numerous alterations of both oncogenes and tumor suppressor genes that have been implicated in bladder carcinogenesis represent novel targets for therapy and prevention. In addition, knowledge about these genetic alterations will help provide a better understanding of the biological significance of preneoplastic lesions of bladder cancer. Animal models for investigating bladder cancer development and prevention can also be developed based on these alterations. This paper summarizes the results of recent preclinical and clinical chemoprevention studies and discusses screening for bladder cancer.

P-cadherin in adhesion and invasion: opposite roles in colon and bladder carcinoma

Neoexpression or upregulation of placental cadherin (P-cadherin), a member of the classical cadherin family, has previously been described in several carcinomas, such as colorectal and bladder carcinomas. In this study, we combined two different approaches, immunohistochemistry of tumor samples and in vitro knockdown of P-cadherin, to gain a better insight into the role of P-cadherin in these types of cancer. First, we performed immunohistochemistry for P- and E-cadherins in a series of 52 colorectal adenocarcinomas, including well, moderately and poorly differentiated (WD, MD, and PD) tumors. Decrease or loss of P-cadherin neoexpression was significantly associated with a higher tumor grade and could discriminate WD from MD and/or PD tumors (p < 0.001). E-cadherin, on the other hand, was strongly expressed at the membrane of most WD (18 of 19) and MD tumors (15 of 19). Downregulation correlated significantly with the PD phenotype (p ≤ 0.001). In a second approach, we transiently or stably knocked down P-cadherin in HT-29 colon adenocarcinoma cells. This led to decreased intercellular adhesion and to an increased migratory and long-term invasive phenotype compared with control HT-29 cells, suggesting that P-cadherin acts as a proadhesive and anti-invasive/antimigratory molecule in colon carcinoma cells. Contrasting with these results and illustrating the context-specific function of P-cadherin were our results obtained in RT-112 bladder carcinoma cells. Stable knockdown of P-cadherin in RT-112 cells diminished invasion and migration, and promoted intercellular adhesion.

Use of fluorescein isothiocyanate-human serum albumin for the intravesical photodiagnosis of non-muscle-invasive bladder cancer: an in vitro study using multicellular spheroids composed of normal human urothelial and urothelial cell carcinoma cell lines

OBJECTIVE

• To evaluate human serum albumin (HSA), fluorescently labelled with fluorescein isothiocyanate (FITC), as a potential intravesical photodiagnostic method for the early detection of non-muscle-invasive bladder cancer.

PATIENTS AND METHODS

• By using multicellular spheroids prepared from normal human urothelial (NHU) cells and from different urothelial cell carcinoma (UCC) cell lines (T24, J82), we simulated three-dimensionally the normal urothelium and non-muscle-invasive UCCs present in the bladder of patients. • The distribution of FITC-HSA in these spheroids was investigated.

RESULTS

• Our data showed that fluorescently labelled albumin is quite evenly dispersed throughout the spheroids. However, in the case of the 10 mg/mL incubations, the fluorescence intensity seems to increase slightly towards the spheroid core. • Using 1 mg/mL, the penetration of FITC-HSA in T24 differed significantly from the penetration in NHU spheroids, but this was not the case for J82 spheroids. • When the concentration of FITC-HSA was increased 10-fold, all UCC spheroids exhibited a significantly different accumulation of FITC-HSA.

CONCLUSIONS

• As spheroids represent a suitable in vitro model for predicting the in vivo behaviour of compounds, our data suggest that FITC-HSA could be used for the early detection of non-muscle-invasive bladder cancer. • Human serum albumin conjugates of new or already available intravesical drugs could be generated to create alternative bladder cancer therapies with increased selectivity.

Granzyme B is expressed in urothelial carcinoma and promotes cancer cell invasion

Granzyme B (GrB) is a serine proteinase known to be expressed by cytotoxic lymphocytes and to induce, in presence of perforin (Pf), apoptosis in target cells. Recently, GrB expression has been shown (often in absence of Pf) in nonlymphoid cells, but its function is not defined. In our study, we investigated GrB and Pf expression in bladder cancer cell lines and in urothelial carcinoma (UC) tissues by reverse transcription-polymerase chain reaction (RT-PCR), Western blot, ELISA, immunofluorescence and immunohistochemistry. We also assessed the function of GrB in UC cells; the in vitro function of GrB was examined by loss-of-function experiments. Our results revealed that GrB is expressed, in absence of Pf, in UC cells. Significant differences were found between GrB expression and both increasing pathological tumor spreading and high-grade vs. low-grade pTa tumors. Notably, GrB in UC tissues was concentrated at the cancer invasion front and was expressed in neoplastic cells undergoing epithelial-mesenchymal transition, a key event in carcinoma invasion. Indeed, GrB-positive cells also expressed Snail, N-cadherin or were negative for E-cadherin. GrB expressed in tumor cell lines was enzymatically active and capable of vitronectin cleavage, implying extracellular matrix (ECM) remodeling by GrB. Inhibition of GrB activity or Stealth RNA interference-mediated GrB gene silencing markedly suppressed bladder cancer cell invasion through matrigel. This data provides the first evidence for a role of GrB in promoting cancer cell invasion. Taken together, our findings suggest that GrB, via ECM degradation, contributes to the establishment of the UC invasive phenotype.

Reciprocal correlation between the expression of cyclooxygenase-2 and E-cadherin in human bladder transitional cell carcinomas

Carcinoma cells become more motile and invasive via downmodulation of E-cadherin. Cyclooxygenase-2 (COX-2) expression is associated with tumor invasion and metastasis. The aim of this study is to investigate the relationship between the expression of COX-2 and E-cadherin in a bladder cancer cell line and human bladder transitional cell carcinoma (TCCs). Phorbol 12-myristate 13-acetate (PMA) treatment for 5637 bladder cancer cells increased COX-2 expression, slightly induced Slug expression, and decreased E-cadherin expression. Ectopic expression of COX-2 or prostaglandin E(2) (PGE(2)) treatment for 5637 cells reduced E-cadherin expression. This finding was confirmed by the result that knockdown of COX-2 expression or indomethacin administration increased the expression of E-cadherin. When compared with cells' motility in serum-free medium, the treatment of PMA and PGE(2) increased cell motility, and indomethacin treatment slightly decreased cell motility. In the tissues of bladder TCCs, COX-2 expression was inversely correlated with membranous E-cadherin expression and positively correlated with nuclear beta-catenin expression. The expression of COX-2 and nuclear beta-catenin expression was significantly higher in TCCs of high grade and invasive growth than in TCCs of low grade and noninvasive growth. In contrast, membranous E-cadherin expression was more decreased in tumors of high grade and invasive growth. In addition, nuclear beta-catenin expression was significantly related to tumor recurrence. We suggest that COX-2 pathway reduces membranous E-cadherin expression in bladder TCCs and their expression pattern may provide important information in predicting the clinical behavior of bladder TCCs.

Cytoplasmic beta-catenin accumulation is a good prognostic marker in upper and lower gastrointestinal adenocarcinomas

AIMS

beta-Catenin is an important molecule in cancer biology. Membranous beta-catenin enhances cellular differentiation and inhibits invasion by its action on E-cadherin. The aim was to ascertain whether the cellular expression of these molecules in colorectal and oesophageal cancer specimens is associated with survival in patients with gastrointestinal cancer.

METHODS AND RESULTS

Tumour samples from 149 patients undergoing resection for colorectal adenocarcinoma and 147 patients undergoing resection for oesophageal adenocarcinoma were retrospectively analysed using immunohistochemical techniques to assess beta-catenin expression. Increasing beta-catenin expression in the cytoplasm was associated with improved survival for colorectal cancer cases on both univariate (P = 0.003) and multivariate (P = 0.01) analysis. In addition, increased expression in the most recent cohort of oesophageal adenocarcinoma patients was associated with improved TNM staging (P = 0.007). Membrane expression was weakly associated with survival in colorectal cancer on univariate analysis (P = 0.09), but not on multivariate analysis (P = 0.21). Complete absence of beta-catenin expression at all three sites was associated with reduced 5-year survival in colorectal cancer.

CONCLUSIONS

This is one of the largest prognostic studies of beta-catenin in gastrointestinal adenocarcinoma. It shows that low levels of cytoplasmic beta-catenin expression are associated with reduced survival in patients with colorectal cancer as well as worse TNM staging in oesophageal adenocarcinoma (a recognized surrogate end-point for survival). We believe this is the first time that this has been reported. This finding should be tested prospectively in oncological trials to validate whether the presence of cytoplasmic beta-catenin could be used as a prognostic marker for less aggressive disease.

Cadherin switching and bladder cancer

PURPOSE

Progression to or presentation with muscle invasive disease represents the critical clinical step in bladder cancer, necessitating more aggressive therapy and carrying a significantly worse survival rate. Bladder tumors typically show decreased expression of the cell-cell adhesion molecule E-cadherin as grade and stage progress, accompanied by increased expression of N-cadherin or P-cadherin in muscle invasive tumors. This phenomenon has been described as cadherin switching and may represent the key step in invasion. We introduce some of the concepts of cadherin mediated cell adhesion and biology, and describe cadherin switching in detail for bladder cancer.

MATERIALS AND METHODS

We performed a PubMed search for articles summarizing important concepts in cadherin biology and presenting primary evidence of cadherin expression in bladder cancer.

RESULTS

Cadherin switching promotes a more malignant and invasive phenotype of bladder cancer in patients and laboratory based experimental systems. Bladder cancer is novel in that a switch to N-cadherin and P-cadherin expression occurs, although the precise timing and nature of this process remain unknown. Similarly the associated signaling pathways remain to be fully elucidated.

CONCLUSIONS

Cadherin switching is an important process late in the molecular pathogenesis of bladder cancer, and it may hold some of the answers to the development of muscle invasive and metastatic disease. Thus, the cadherin cell adhesion molecules represent strong candidate biological and molecular targets for preventing disease progression, and further investigation is warranted.

Defects in muscarinic receptor cell signaling in bladder urothelial cancer cell lines

INTRODUCTION

To explore muscarinic receptor signaling in 4 bladder cancer cell lines, bladder urothelial cells (BUC) have been shown to release and respond to various putative neurotransmitters.

METHODS

Reverse transcription-polymerase chain reaction was used to detect the presence of m1-m5 transcripts in the J82, RT4, T24, and 5637 lines of cancer BUC. Immunofluorescence was used to detect expression of m3 protein. Cancer and normal BUC were stimulated with carbachol (100 microM), a muscarinic agonist. Carbachol-evoked changes in intracellular calcium ([Ca(2+)](i)) levels were measured using fura-2 ratiometric microfluorimetry. Transfection of J82 cells with m3 plasmid was performed, and changes in carbachol-evoked [Ca(2+)](i) were re-examined.

RESULTS

None of the cancer cell lines expressed m3 transcripts, unlike normal BUC, which expressed m3. None of the 4 bladder cancer cell lines responded to carbachol. However, 47% of normal BUC responded to carbachol. The m3-transfected J82 cells expressed both m3 transcript and protein. Thirteen percent of m3-transfected J82 cells responded to carbachol.

CONCLUSIONS

This is the first description of altered muscarinic signaling in cancer BUC. Unlike normal BUC, bladder urothelial cancer cells neither expressed m3 transcript nor responded to carbachol, as measured by changes in [Ca(2+)](i). We could partially reverse this defect in one of the cancer cell lines, J82, by transfecting these cells with the m3 plasmid. Although the effects of muscarinic receptor signaling on urothelial cell are unknown, this signaling pathway may play a role in urothelial cell adhesion similar to that in keratinocytes.

Ectopic expression of P-cadherin correlates with promoter hypomethylation early in colorectal carcinogenesis and enhanced intestinal crypt fission in vivo

P-cadherin is normally expressed in the basal layer of squamous epithelia and absent from the healthy intestine and colon. We have previously shown it to be expressed in all inflamed, hyperplastic, and dysplastic intestinal and colonic mucosa. This study aimed to better understand the mechanisms controlling the expression of P-cadherin and the biological effects of its ectopic presence in the intestine and colon. We investigated the CpG methylation status of the P-cadherin (CDH3) promoter and P-cadherin mRNA and protein expression in cases of familial and sporadic colorectal cancer (CRC). The CDH3 promoter was hypomethylated in colonic aberrant crypt foci, in CRC, and, occasionally, in the normal epithelium adjacent to cancer, demonstrating a potential "field effect" of cancerization. The hypomethylation was also associated with induction of P-cadherin expression in the neoplastic colon (P < 0.0001). We then created transgenic mice that overexpressed P-cadherin specifically in the intestinal and colonic epithelium under the liver fatty acid binding protein promoter. Forced ectopic expression of P-cadherin accompanied by indomethacin-induced inflammation resulted in a 3-fold higher crypt fission rate within the small and large intestines in the homozygous mice compared with the wild-type animals (P < 0.02). We conclude that epigenetic demethylation of the P-cadherin promoter in the human intestine permits its ectopic expression very early in the colorectal adenoma-carcinoma sequence and persists during invasive cancer. Induced P-cadherin expression, especially in mucosal damage, leads to an increased rate of crypt fission, a common feature of clonal expansion in gastrointestinal dysplasia.