Hypermethylation of an E-cadherin (CDH1) promoter region in high grade transitional cell carcinoma of the bladder comprising carcinoma in situ

Intravesical Contrast-Enhanced MRI: A Potential Tool for Bladder Cancer Surveillance and Staging

This review article gives an overview of the current state of the art of bladder cancer imaging and then discusses in depth the scientific and technical merit of a novel imaging approach, tracing its evolution from murine cancer models to cancer patients. While the poor resolution of soft tissue obtained by widely available imaging options such as abdominal sonography and radiation-based CT leaves them only suitable for measuring the gross tumor volume and bladder wall thickening, dynamic contrast-enhanced magnetic resolution imaging (DCE MRI) is demonstrably superior in resolving muscle invasion. However, major barriers still exist in its adoption. Instead of injection for DCE-MRI, intravesical contrast-enhanced MRI (ICE-MRI) instills Gadolinium chelate (Gadobutrol) together with trace amounts of superparamagnetic agents for measurement of tumor volume, depth, and aggressiveness. ICE-MRI leverages leaky tight junctions to accelerate passive paracellular diffusion of Gadobutrol (604.71 Daltons) by treading the paracellular ingress pathway of fluorescein sodium and of mitomycin (<400 Daltons) into bladder tumor. The soaring cost of diagnosis and care of bladder cancer could be mitigated by reducing the use of expensive operating room resources with a potential non-surgical imaging option for cancer surveillance, thereby reducing over-diagnosis and over-treatment and increasing organ preservation.

DNA Methylation and Flavonoids in Genitourinary Cancers

Malignancies of the genitourinary system have some of the highest cancer incidence and mortality rates. For example prostate cancer is the second most common cancer in men and ovarian cancer mortality and incidence are near equal. In addition to genetic changes modulation of the epigenome is critical to cancer development and progression. In this regard epigenetic changes in DNA methylation state and DNA hypermethylation in particular has garnered a great deal of attention. While hypomethylation occurs mostly in repeated sequence such as tandem and interspersed repeats and segment duplications, hypermethylation is associated with CpG islands. Hypomethylation leads to activation of cancer-causing genes with global DNA hypomethylation being commonly associated with metastatic disease. Hypermethylation-mediated silencing of tumor suppressive genes is commonly associated with cancer development. Bioactive phytochemicals such as flavonoids present in fruits, vegetables, beverages etc. have the ability to modulate DNA methylation status and are therefore very valuable agents for cancer prevention. In this review we discuss several commonly methylated genes and flavonoids used to modulate DNA methylation in the prevention of genitourinary cancers.

Reduced 5-methylcytosine level as a potential progression predictor in patients with T1 or non-invasive urothelial carcinoma

This study aims to elucidate the level of DNA methylation in urothelial carcinomas (UCs) using 5-methylcytosine (5-MeC) immunohistochemistry (IHC). We examined the relationship among 5-MeC levels, DNA (cytosine-5)-methyltransferase 1 (DNMT1) immunostaining levels, and clinicopathologic features. Tissue samples included 23 normal urothelia and 150 urothelial neoplasia, which comprised 40 non-invasive and 110 invasive UCs. The levels of 5-MeC and DNMT1 were assessed based on their immunoreactivities and then divided into low and high levels. In addition, we collected information on clinical variables, pathologic features, and recurrent status from patient questionnaires and medical records. Chi-square test and multivariate logistic regression model were used for analyses. Results showed that 5-MeC levels were positively associated with DNMT1 levels in UC (p = 0.0288). Both 5-MeC and DNMT1 were low in approximately 50% (76/150) of UC. The percentage of low 5-MeC levels was higher in invasive UC (65/110; 59%) than in normal urothelia (2/23; 13%) and non-invasive UC (18/40; 45%). Clinical factors were independently associated with low 5-MeC levels after adjusting for age and sex, including cancer stages II-IV, presence of UC in situ, and marked inflammation. Low 5-MeC levels in stage I invasive UC were not significantly different from those of non-invasive tumors (p = 0.8478). Low DNMT1 levels were only associated with UC with squamous differentiation (p = 0.0365). Neither 5-MeC nor DNMT1 levels were associated with UC recurrence. In conclusion, a low 5-MeC level could predict the progression of UC invasion into muscle.

Hypermethylation in bladder cancer: biological pathways and translational applications

A compelling body of evidences sustains the importance of epigenetic mechanisms in the development and progression of cancer. Assessing the epigenetic component of bladder tumors is strongly improving our understanding of their biology and clinical behavior. In terms of DNA methylation, cancer cells show genome-wide hypomethylation and site-specific CpG island promoter hypermethylation. In the context of other epigenetic alterations, this review will focus on the hypermethylation of CpG islands in promoter regions, as the most widely described epigenetic modification in bladder cancer. CpG islands hypermethylation is believed to be critical in the transcriptional silencing and regulation of tumor suppressor and crucial cancer genes involved in the major molecular pathways controlling bladder cancer development and progression. In particular, several biological pathways of frequently methylated genes include cell cycle, DNA repair, apoptosis, and invasion, among others. Furthermore, translational aspects of bladder cancer methylomes described to date will be discussed towards their potential application as bladder cancer biomarkers. Several tissue methylation signatures and individual candidates have been evidenced, that could potentially stratify tumors histopathologically, and discriminate patients in terms of their clinical outcome. Tumor methylation profiles could also be detected in urinary specimens showing a promising role as non-invasive markers for cancer diagnosis towards an early detection and potentially for the surveillance of bladder cancer patients in a near future. However, the epigenomic exploration of bladder cancer has only just begun. Genome-scale DNA methylation profiling studies will further highlight the relevance of the epigenetic component to gain knowledge of bladder cancer biology and identify those profiles and candidates better correlating with clinical behavior.

RUNX3 methylation as a predictor for disease progression in patients with non-muscle-invasive bladder cancer

BACKGROUND AND OBJECTIVES

We have previously reported that RUNX3 inactivation by promoter hypermethylation correlated with advanced disease and poor clinical outcome in bladder cancer. In this study, we examined primary tumors from non-muscle-invasive bladder cancer (NMIBC) patients in order to investigate the relationship between RUNX3 methylation and disease progression.

METHODS

The association between the hypermethylation of RUNX3 and clinicopathological characteristics of 186 NMIBC samples was analyzed using methylation-specific polymerase chain reaction (MS-PCR).

RESULTS

RUNX3 methylation was associated with increased tumor stage, grade, and number of tumors (each P < 0.05). Kaplan-Meier estimates revealed significant differences in time to recurrence and progression based on RUNX3 methylation status (P = 0.043 and 0.006, respectively). RUNX3 methylation was an independent predictor of NMIBC progression on univariate and multivariate analysis. Combining tumor grade and RUNX3 methylation status demonstrated that patients with G3 tumors with RUNX3 methylation had a worse progression-free survival compared with the patients with lower-grade or unmethylated tumors [hazard ratio (HR), 19.450].

CONCLUSIONS

RUNX3 methylation status predicted the risk of NMIBC progression independently of tumor stage. In conjunction with tumor grade, RUNX3 methylation status in patients with NMIBC strongly predicts disease progression.

Epithelial-mesenchymal transition in mouse mammary tumorigenesis

Epithelial-mesenchymal transition tumorigenesis in the mouse has been described for over 100 years using various terms and with little comprehension of the underlying mechanisms. Recently, epithelial-mesenchymal transition tumors have been recognized in mammary glands of genetically engineered mice. This review provides a historical perspective and the current observations in the context of some of the key molecular biology. The biology of mouse mammary epithelial-mesenchymal transition tumorigenesis is discussed with comparisons to human breast cancer.

Epigenetic biomarkers in urothelial bladder cancer

Bladder cancers comprise heterogeneous cell populations, and numerous factors are likely to be involved in dictating recurrence, progression and patient survival. While several molecular markers that are used to evaluate the development and prognosis of bladder cancer have been studied, the limited value of these established markers has created the need for new molecular indicators of bladder cancer prognosis. Of particular interest is the silencing of tumor-suppressor genes by epigenetic alteration. Recent progress in understanding epigenetic modification and gene silencing has led to new opportunities for the understanding, detection, treatment and prevention of cancer. Moreover, epigenetic silencing of tumor-suppressor genes is interesting from a clinical standpoint, because of the possibility of reversing epigenetic changes and restoring gene function in a cell. This review focuses on the prognostic relevance of epigenetic markers in bladder cancer.

E-cadherin expression in upper urothelial carcinoma in Balkan Endemic Nephropathy and non-endemic regions

There is a high incidence of upper urothelial carcinoma (UUC) in regions affected by Balkan Endemic Nephropathy (BEN). The aim of this study was to compare E-cadherin expression in UUC, in regions affected by BEN, and in control rural and city populations free of BEN. Another aim was to determine the influence of some morphological parameters on the E-cadherin status. In the samples of 85 UUC patients, of whom 40 lived in BEN settlements and 45 served as control subjects, immunoreactions were performed using monoclonal anti-human E-cadherin antibody. Aberrant expression of E-cadherin was more frequent in BEN tumors than in control tumors (p<0.01). Decreased E-cadherin expression was linked to high grade and solid growth in control and BEN tumors (p<0.0001 and <0.05 versus p<0.05 and <0.05, respectively), and to the stage in control tumors (p<0.01). However, BEN low grade and low stage tumors showed aberrant expression more often than did control tumors (p<0.05 and <0.005, respectively). In control tumors, using univariate analysis, E-cadherin status was found to be influenced by grade, stage, and tumor growth (p=0.001, 0.017, 0.015, respectively). In the same group, only the grade was significant according to multistep logistic regression analysis (Wald=6.429 and p=0.011). The growth pattern had a predominant influence on E-cadherin expression in BEN tumors (p=0.005). A significant influence on normal membranous or abnormal cytoplasmic expression of E-cadherin in UUC is exerted by tumor grade, stage, growth, and metaplastic change (p=0.002, 0.048, 0.019, 0.011, respectively), but only by tumor grade in the multistep logistic regression model. These results suggest that decreased expression of E-cadherin in BEN tumors may be linked to tumor growth, while expression of E-cadherin in control tumors may be associated with tumor grade.

Increase sensitivity in detecting superficial, low grade bladder cancer by combination analysis of hypermethylation of E-cadherin, p16, p14, RASSF1A genes in urine

OBJECTIVES

To identify a better set of DNA methylation markers to detect superficial, low grade cancer cell in urine sediment for improving cancer treatment, morbidity, and mortality.

MATERIALS AND METHODS

Methylation-specific PCR (MSP) assay was used to detect promoter hypermethylation in 4 genes (E-cadherin, p16, p14, and RASSF1A) to identify reliable biomarkers for bladder cancer diagnosis in primary tumor DNA and urine sediment DNA from 57 bladder cancer patients. Urine DNA was compared with 20 healthy controls.

RESULTS

Fifty-one (90%) tumor DNA and 47 urine DNA (83%) samples from bladder cancer patients revealed hypermethylation in at least 1 of the 4 analyzed genes, whereas all urine samples from normal controls were negative. The sensitivity of MSP assay for detecting E-cadherin, p16, p14 and RASSF1A in tumor cells in voided urine was 35%, 35%, 33%, and 65%, respectively. Diagnostic sensitivity was 75% for combining RASSF1A and p14, and 83% for RASSF1A, p14 and E-cadherin. Urine cytology, however, detect only 13 (28%) cases of cancer or suspicious cancer. For detecting superficial and invasive bladder tumor, urine cytology revealed a sensitivity of 23% (6/26) and 35% (7/20), respectively. In contrast, MSP detected hypermethylation in the urine of 80% (37/46) bladder cancer patients. Moreover, hypermethylation analysis of E-cadherin, p14 or RASSF1A genes in urine sediment DNA detected in 85% (22/26) of superficial, 85% (11/13) of low grade, 75% (15/20) of invasive and 79% (26/33) of high grade bladder cancers. Importantly, hypermethylation was detected in the urine DNA of 90% (18/20) superficial tumors with negative or atypia cytology.

CONCLUSIONS

Hypermethylation of E-cadherin, p14 or RASSF1A in urine sediment DNA is a potential biomarker for detecting superficial, low grade cancer. Besides, hypermethylation of these 3 genes is a valuable adjunct diagnostic marker to urine cytology, which can enhance the diagnostic accuracy and follow-up treatment of bladder cancer patients.

Unmethylated E-cadherin gene expression is significantly associated with metastatic human prostate cancer cells in bone

BACKGROUND

The concurrent determination of methylation status of E-cadherin gene and E-cadherin protein expression remains scant in metastatic prostate cancer cells in bone, the most prevalent site for metastatic growth. Therefore, the study was undertaken to ascertain the methylation status of E-cadherin gene, a most frequent and known epigenetic mechanism of its regulation, and the protein expression in prostate tissue biopsy specimen.

METHODS

The methylation of E-cadherin gene was determined by methylation specific-PCR and the protein expression by immunohistochemical method in the consecutive sections of each prostate tissue biopsy specimen.

RESULTS

The unmethylated E-cadherin gene and homogeneous E-cadherin protein expression was significantly associated with BPH as compared to the primary prostate carcinoma (Fisher's Exact P < 0.001). A significant association was observed between the concurrent methylated gene and markedly reduced expression of the protein in the primary prostate cancer cells as compared to the BPH cells, suggesting methylation-dependent regulation of the gene expression in these cases. In contrast to the primary cancer, a highly significant increase in the frequency of metastatic prostate cancer cells in bone exhibited the concurrent expression of unmethylated gene and homogeneous protein (Fisher's Exact P < 0.001).

CONCLUSIONS

The study clearly demonstrated a significant association of the concurrent expression of unmethylated E-cadherin gene and E-cadherin protein with metastatic prostate cancer cells in bone, and that its expression may have a role in the intercellular adhesion in the formation of metastatic lesions in bone.

Cell Discohesion and Multifocality of Carcinoma In situ of the Bladder: New Insight From the Adhesion Molecule Profile (e-Cadherin, Ep-CAM, and MUC1)

Urothelial cell carcinoma in situ (CIS) of the bladder is a superficially diffusive and highly discohesive disease. The authors analyzed the expression of some adhesion molecules (e-cadherin and Ep-CAM) and MUC1 in 32 unifocal and multifocal bladder urothelial cell CIS in an attempt to clarify this discohesion. E-cadherin was strongly expressed, in more than 75% of the cases. The presence of methylation of the CDH1 e-cadherin promoter gene was also investigated, but methylation was found in only one case. Ep-CAM was present in all the cases with a heterogeneous staining pattern. Similarly, MUC1/episialin was variously present in 94% of the cases without a polarized staining pattern and was expressed more strongly in cases with multifocal disease. Because loss of MUC1 polarization leads to interference with cell—cell adhesion mechanisms mediated by cadherins, these findings help explain why bladder urothelial cell CIS often shows a discohesive morphology and multifocality despite a strongly expressed adhesion molecule profile. Finally, Ep-CAM expression might provide some support for future target therapy trials.

Epigenetics in bladder cancer

Bladder cancer (BC) is the second most common malignancy of the genitourinary tract and the second leading cause of cancer death in patients with urinary tract malignancies. DNA methylation and histone modifications are important epigenetic mechanisms of gene regulation and play essential roles both independently and cooperatively in tumor initiation and progression. Aberrant epigenetic events such as DNA hypermethylation and altered histone acetylation have both been observed in bladder cancer, in which they affect a large number of genes. Although the list of aberrantly epigenetically regulated genes continues to grow, combination analysis including several candidate genes has given promising results of potential tumor biomarkers for the early diagnosis and risk assessment of bladder cancer. Thus, large-scale screening of aberrant epigenetic events such as DNA hypermethylation is needed to identify bladder cancer-specific epigenetic fingerprints. The reversibility of epigenetic aberrations has made them attractive targets for cancer treatment with modulators that demethylate DNA and inhibit histone deacetylases, leading to the reactivation of silenced genes. In this review, we examine the current literature on epigenetic changes in bladder cancer and discuss the clinical potential of cancer epigenetics for the diagnosis and treatment of this disease.

DNA methylation patterns in bladder cancer and washing cell sediments: a perspective for tumor recurrence detection

Background

Epigenetic alterations are a hallmark of human cancer. In this study, we aimed to investigate whether aberrant DNA methylation of cancer-associated genes is related to urinary bladder cancer recurrence.

Methods

A set of 4 genes, including CDH1 (E-cadherin), SFN (stratifin), RARB (retinoic acid receptor, beta) and RASSF1A (Ras association (RalGDS/AF-6) domain family 1), had their methylation patterns evaluated by MSP (Methylation-Specific Polymerase Chain Reaction) analysis in 49 fresh urinary bladder carcinoma tissues (including 14 cases paired with adjacent normal bladder epithelium, 3 squamous cell carcinomas and 2 adenocarcinomas) and 24 cell sediment samples from bladder washings of patients classified as cancer-free by cytological analysis (control group). A third set of samples included 39 archived tumor fragments and 23 matched washouts from 20 urinary bladder cancer patients in post-surgical monitoring. After genomic DNA isolation and sodium bisulfite modification, methylation patterns were determined and correlated with standard clinic-histopathological parameters.

Results

CDH1 and SFN genes were methylated at high frequencies in bladder cancer as well as in paired normal adjacent tissue and exfoliated cells from cancer-free patients. Although no statistically significant differences were found between RARB and RASSF1A methylation and the clinical and histopathological parameters in bladder cancer, a sensitivity of 95% and a specificity of 71% were observed for RARB methylation (Fisher's Exact test (p < 0.0001; OR = 48.89) and, 58% and 17% (p < 0.05; OR = 0.29) for RASSF1A gene, respectively, in relation to the control group.

Conclusion

Indistinct DNA hypermethylation of CDH1 and SFN genes between tumoral and normal urinary bladder samples suggests that these epigenetic features are not suitable biomarkers for urinary bladder cancer. However, RARB and RASSF1A gene methylation appears to be an initial event in urinary bladder carcinogenesis and should be considered as defining a panel of differentially methylated genes in this neoplasia in order to maximize the diagnostic coverage of epigenetic markers, especially in studies aiming at early recurrence detection.

Methylation of the RUNX3 promoter as a potential prognostic marker for bladder tumor

PURPOSE

DNA methylation is a key regulator of gene transcription and genomic stability, and alterations in DNA methylation patterns are frequently detected in human tumors. Previously we reported that inactivation of RUNX3 by primarily epigenetic alterations in DNA methylation is closely associated with bladder tumor development, recurrence and progression. In the current series we evaluated the association between RUNX3 inactivation and bladder tumors after a long-term followup study.

MATERIALS AND METHODS

We used previously published data on the methylation patterns of RUNX3 in bladder tumor samples as well as 25 new data sets obtained by methylation specific polymerase chain reaction and direct DNA sequencing. Of the 149 patients examined 118 were followed periodically and included in the final analysis. Median followup was 49.8 months (range 1 to 146).

RESULTS

RUNX3 promoter methylation was observed in 84 of the 118 tumor samples (71.2%) examined. RUNX3 methylation patterns correlated significantly with the development of invasive tumor, tumor progression, and overall and cancer specific survival (each p <0.05). Kaplan-Meyer curves showed identical results (p <0.05). Multivariate Cox regression models revealed that RUNX3 methylation status was a strong predictor of tumor progression and cancer specific survival.

CONCLUSIONS

Results strongly suggest that inactivation of RUNX3 by the methylation of its promoter region is a significant risk factor for invasive bladder tumors, tumor progression and cancer specific survival. RUNX3 promoter methylation status could be a promising marker for assessing the prognosis of human bladder tumors.

[DNA methylation on urinalysis and as a prognostic marker in urothelial cancer of the bladder]

INTRODUCTION AND OBJECTIVES

Detection of promoter hypermethylation has been proposed as a promising tool for cancer diagnosis and as a prognostic marker in various cancers. We studied the versatility of DNA methylation for noninvasive diagnosis and as a prognostic marker for non-muscle-invasive bladder carcinoma.

METHODS

Tumor specimens were microdissected and DNA was extracted from 105 paraffin-embedded paraffin specimens from patients undergoing transurethral resection for non-muscle-invasive bladder carcinoma. Urine specimens were collected from patients undergoing cystectomy for bladder cancer and from healthy volunteers. Methylation status was assessed with the real-time quantitative methylation-sensitive PCR (MethyLight). We checked a panel of 20 cancer-associated genes (p14ARF, p16 CDKN2A, STAT-1, SOCS-1, DR-3, DR-6, PIG-7, BCL-2, H-TERT, BAX, EDNRB, DAPK, RASSF-1A, FADD, TMS-1, E-CADHERIN, ICAM-1, TIMP-3, MLH-1, COX-2) for DNA methylation.

RESULTS

Follow-up data were available in 95 of 105 patients (91.4%). A tumor recurrence was observed in 26 patients (27.3%). We could identify six genes (SOCS-1, STAT-1, BCL-2, DAPK, TIMP-3, E-cadherin), where methylation was associated with tumor recurrence. In Kaplan-Meier analysis, TIMP-3 showed a significant association with recurrence-free survival. Methylation of TIMP-3 predicted prolonged disease-free interval. Regarding urinalysis we could identify a pattern of methylation markers including DAPK, BCL-2, and H-TERT that yielded a sensitivity of 81.1% with a specificity of 100% in a cancer-free control population

CONCLUSIONS

We present data on the clinical usefulness of methylation analysis in bladder carcinoma. Our data confirm that methylation analysis is a promising tool for bladder cancer diagnosis and prognosis.

Genetic and epigenetic biomarkers in cancer : improving diagnosis, risk assessment, and disease stratification

Gene expression patterns change during the initiation, progression, and development of cancer, as a result of both genetic and epigenetic mechanisms. Genetic changes arise due to irreversible changes in the nucleotide sequence, whereas epigenetic changes occur due to changes in chromatin conformation, histone acetylation, and methylation of the CpG islands located primarily in the promoter region of a gene. Both genetic and epigenetic markers can potentially be utilized to identify different stages of tumor development. Several such markers exhibit high sensitivity and specificity for different tumor types and can be assayed in biofluids and other specimens collected by noninvasive technologies. In spite of the availability of large numbers of diagnostic markers, only a few have been clinically validated so far. The current status and the challenges in the field of genetic and epigenetic markers in cancer diagnosis, risk assessment, and disease stratification are discussed.

The role of deoxyribonucleic acid methylation in development, diagnosis, and prognosis of bladder cancer

Alterations in global levels and regional patterns of deoxyribonucleic acid methylation are among the earliest and most common events known to occur in human cancer. The mutational and epigenetic effects of this covalent deoxyribonucleic acid modification to the development of bladder cancer are well recognized. The contribution of aberrant methylation to mutational hot spots located within genes, transcriptional silencing, and chromosomal instability is reviewed in the context of its relevance to bladder carcinogenesis. Understanding how such processes evolve during the progression of bladder cancer is essential for using these molecular changes in the clinical setting. The recent development of sensitive and specific techniques for quantifying methylation changes in urine specimens and bodily fluids underscores the potential use of this molecular marker for early detection and surveillance of bladder cancer. Further refinement of these molecular biological techniques holds much promise for the use of methylation markers for bladder cancer diagnosis, risk stratification, and disease prognostication.

Genetic alterations in bladder cancer and their clinical applications in molecular tumor staging

Molecular biology is expected to provide new tools and approaches to assess the prognosis of patients with bladder cancer, by providing information on the risks of tumor recurrence and progression from superficial bladder cancer to an invasive phenotype. Genetic and epigenetic alterations have been closely associated with bladder carcinogenesis and progression, although most of these are still under investigation in a preclinical setting. This article highlights current findings from molecular studies, and describes their potential application in molecular staging of bladder cancer.

E-cadherin promoter polymorphism (C-160A) and risk of recurrence in patients with superficial bladder cancer

Tumor recurrence is a hallmark of superficial bladder cancer. Currently, a molecular marker for bladder cancer recurrence is lacking. E-cadherin plays an important role in epithelial development and in the establishment and maintenance of cell-cell adhesion and tissue architecture. The purpose of this study is to investigate the association of an E-cadherin promoter polymorphism (CDH1c-160a) with the risk of bladder cancer recurrence. This study included 302 patients with superficial bladder cancer. Genomic DNA was extracted from peripheral blood lymphocytes and genotyping was performed using Taqman assay. Clinical data were collected by medical chart review. Cox proportional hazard model was used to estimate the hazard ratios (HRs) associated with genotypes while adjusting for age, gender, smoking status, tumor stage and grade where appropriate. During a median follow-up of 27.65 months, 151 patients experienced disease recurrence. Subsequent analyses were restricted to Caucasians only due to the small sample size of other ethnic groups (13 in recurrence group and 15 in non-recurrence group). Among the 274 Caucasian patients, 138 developed recurrence during the same length of follow-up time. In Caucasian patients, having at least one variant A allele conferred a 32% reduction in recurrence risk (adjusted HR: 0.68; 95% CI: 0.48-0.96). The median recurrence-free survival for patients carrying at least one variant A allele was significantly longer than that for patients with a homozygous CC genotype (40.4 vs 12.5 months, p=0.04). Our findings suggest that the E-cadherin promoter polymorphism may be a valuable molecular marker for bladder cancer recurrence.

The application of epigenetic modifiers on the treatment of prostate and bladder cancer

Prostate cancer and transitional cell carcinoma (TCC) of bladder are the 2 most common malignancies in the male adult urogenital system. Epigenetic gene silencing, particularly tumor suppressor genes, has become a new area of cancer research. Agents such as deoxyribonucleic acid methyltransferase inhibitors or histone deacetylase inhibitors are epigenetic modifiers that can restore gene expression and alter the malignant phenotype of cancer. They provide a new therapeutic avenue for prostate cancer and TCC. It is also likely that combination regimens using epigenetic modifiers with other classes of agents may have higher therapeutic efficacy for prostate cancer and TCC, especially metastatic and/or refractory cases. We review current knowledge of epigenetic event in prostate cancer and TCC, and discuss the possible clinical implications for these 2 diseases.

Development and progression of urothelial carcinoma

Urothelial carcinomas are well known to feature multifocal development in the urinary tract, both synchronously and asynchronously. This phenomenon can be explained by either seeding of cancer cells in the urinary tract or field cancerization. As there are two characteristic morphological patterns of urothelial carinomas, papillary and nodular, published papers were here reviewed to understand the development and progression of urothelial carcinoma regarding multifocality due to seeding or field changes with reference to the type of urothelial carcinoma. From animal experiments using rats, mice and dogs treated with N-butyl-N-(4-hydoroxybutyl) nitrosamine, and from pathological observation of human cystectomy specimens on step-sectioning and molecular analysis, nodular carcinomas appear to either develop via papillary carcinomas or de novo. Clinical aspects of multifocal tumor development are outside of the scope of this review, although an understanding of the mechanisms underlying multifocality and the papillary/nodular morphological relationship is important to determine follow-up strategies for patients treated for primary urothelial carcinomas and for reconstruction of the urinary tract after cystectomy.

Quantitation of promoter methylation of multiple genes in urine DNA and bladder cancer detection

BACKGROUND

The noninvasive identification of bladder tumors may improve disease control and prevent disease progression. Aberrant promoter methylation (i.e., hypermethylation) is a major mechanism for silencing tumor suppressor genes and other cancer-associated genes in many human cancers, including bladder cancer.

METHODS

A quantitative fluorogenic real-time polymerase chain reaction (PCR) assay was used to examine primary tumor DNA and urine sediment DNA from 15 patients with bladder cancer and 25 control subjects for promoter hypermethylation of nine genes (APC, ARF, CDH1, GSTP1, MGMT, CDKN2A, RARbeta2, RASSF1A, and TIMP3) to identify potential biomarkers for bladder cancer. We then used these markers to examine urine sediment DNA samples from an additional 160 patients with bladder cancers of various stages and grades and from an additional 69 age-matched control subjects. Data were analyzed on the basis of a prediction model and were internally validated using a jacknife procedure. All statistical tests were two-sided.

RESULTS

For all 15 patients with paired DNA samples, the promoter methylation pattern in urine matched that in the primary tumors. Four genes displayed 100% specificity. Of the 175 bladder cancer patients, 121 (69%, 95% confidence interval [CI] = 62% to 76%) displayed promoter methylation in at least one of these genes (CDKN2A, ARF, MGMT, and GSTP1), whereas all control subjects were negative for such methylation (100% specificity, 95% CI = 96% to 100%). A logistic prediction model using the methylation levels of all remaining five genes was developed and internally validated for subjects who were negative on the four-gene panel. This combined, two-stage predictor produced an internally validated ROC curve with an overall sensitivity of 82% (95% CI = 75 % to 87%) and specificity of 96% (95% CI = 90% to 99%).

CONCLUSION

Testing a small panel of genes with the quantitative methylation-specific PCR assay in urine sediment DNA is a powerful noninvasive approach for the detection of bladder cancer. Larger independent confirmatory cohorts with longitudinal follow-up will be required in future studies to define the impact of this technology on early detection, prognosis, and disease monitoring before clinical application.

E-Cadherin expression in transitional cell carcinomas

The authors analyzed the expression of E-cadherin, one of the most important cell adhesion molecules, on histological slides of tumors of bladder cancer patients. The aim of the study was to see whether there is any association between E-cadherin expression and tumor grade, stage, age and gender of the patients, number of recurrences, or overall survival. The samples were examined in 51 primary bladder transitional cell carcinomas (TCC) of 50 patients, resected by transurethral resection (TUR) between January 1, 1996 and January 1, 1997. Immunoreactions were performed with monoclonal anti-human E-cadherin antibody. Forty of the fifty patients could be clinically followed. The analysis of the results on these forty patients was performed by contingency analysis and significance was assessed by chi2 test. No significant association between E-cadherin expression and tumor grade, stage, age or gender of the patients, the number of recurrences, or overall survival could be seen.

Evidence for the early onset of aberrant promoter methylation in urothelial carcinoma

There is evidence that carcinoma in situ (CIS) is the precursor of invasive urothelial carcinoma, a tumour characterized by frequent gene promoter methylation. The timing of altered DNA methylation is unknown in this pathway. Here we investigate gene methylation in 196 consecutive samples of normal urothelium, CIS, and tumours from 104 patients with both CIS and invasive urothelial carcinoma using quantitative methyl-sensitive polymerase chain reaction for six genes (p16, p14, E-cadherin, RARbeta2, RASSF1a, and GSTP1). Control normal urothelial samples from 15 patients with no history of urothelial carcinoma were also analysed. Immunohistochemistry established the expression of well-characterized CIS markers p53 and cytokeratin 20. Promoter methylation occurred frequently in both normal urothelium and CIS samples from patients with urothelial carcinoma, and increased with progression from normal to invasive urothelial carcinoma, at both specific loci (chi2 test: E-cadherin, p=0.0001; RASSF1a, p=0.003, RARbeta2, p=0.007, p16, p=0.024) and in general (methylation indices [t-test, p<0.0001]). Methylation was associated with cytokeratin 20 expression (t-test, p=0.004) and poor prognosis, and with increased progression to tumour death in patients whose CIS samples showed methylation, in comparison with those without methylation (log rank p<0.03). Promoter methylation occurs early in the urothelial carcinogenic pathway and appears to be a good biomarker of the invasive urothelial carcinoma phenotype.

Prognostic relevance of methylation markers in patients with non-muscle invasive bladder carcinoma

There is increasing evidence for the role of epigenetic gene silencing in superficial bladder cancer. The aim of the current study was to investigate the prognostic value of epigenetic alterations in patients with non-muscle invasive bladder carcinoma. We checked the methylation status of 20 cancer associated genes (p14ARF, p16 CDKN2A, STAT-1, SOCS-1, DR-3, DR-6, PIG-7, BCL-2, H-TERT, BAX, EDNRB, DAPK, RASSF-1A, FADD, TMS-1, E-Cadherin, ICAM-1, TIMP-3, MLH-1, COX-2) for DNA methylation. We analysed microdissected tumour samples from 105 consecutive patients with primary non-muscle invasive bladder carcinoma. Quantitative methylation analysis of CpG sites in the promoter region of the genes was performed with methylation sensitive quantitative real time PCR ('Methylight'). Univariate analysis for association with tumour recurrence was carried out with the Kaplan-Meier analysis and the log-rank test. Follow-up data were available in 95/105 patients (91.4%). A tumour recurrence was observed in 26 patients (27.3%). We could identify six genes (SOCS-1, STAT-1, BCL-2, DAPK, TIMP-3, E-Cadherin), where methylation was associated with tumour recurrence. In Kaplan-Meier analysis, TIMP-3 showed a significant association with recurrence free survival. Methylation of TIMP-3 predicted prolonged disease free interval. In this study, we report a comprehensive analysis on prognostic relevance of gene methylation in non-muscle invasive bladder cancer. We identified one gene (TIMP-3) where methylation was associated with a more favourable outcome. Our data strongly support the usefulness of gene methylation as a prognostic marker in patients with non-muscle invasive bladder cancer.

The src-family kinase inhibitor PP2 suppresses the in vitro invasive phenotype of bladder carcinoma cells via modulation of Akt

OBJECTIVE

To evaluate PP2 as a modulator of the cadherin/catenin complex in late-stage bladder carcinoma cells, and to assess its potential invasion-suppressor activity in this model.

MATERIALS AND METHODS

A panel of five human bladder carcinoma cells, characterizing late-stage disease, was used to determine the concentration for 50% inhibition of PP2 in cell-proliferation assays. Modulation of cadherin/catenin expression by PP2 was determined in Western blot analysis, with an assessment of the activation status of mitogen-activated protein kinase and Akt signalling pathways. Altered invasive capacity linked to these variables was determined in standard in vitro invasion assays.

RESULTS

PP2 elicited concentration-dependent growth inhibition in all bladder cell lines within the panel, with growth suppression recorded at 10-35 micromol/L PP2. Distinct morphological changes were recorded in cell lines exposed to PP2, accompanied by up-regulation of plakoglobin expression in a subset of lines. Exposure of cells to PP2 resulted in inactivation of Akt in all cells and a concomitant reduction in in vitro invasive capacity.

CONCLUSIONS

These results show that PP2 inhibits bladder carcinoma cell growth and can modulate plakoglobin expression in a subset of cell lines. In addition, PP2 can suppress the in vitro invasive capacity of bladder carcinoma cells by modulating the activation status of Akt.

Genetic and epigenetic aspects of bladder cancer

Transitional cell carcinoma of the urinary bladder has a diverse collection of biologic and functional characteristics. This is reflected in differing clinical courses. The diagnosis of bladder cancer is based on the information provided by cystoscopy, the gold standard in combination with urinary cytology findings. Many tumor markers have been evaluated for detecting and monitoring the disease in serum, bladder washes, and urinary specimens. However, none of these biomarkers reported to date has shown sufficient sensitivity and specificity for the detection of the whole spectrum of bladder cancer diseases in routine clinical practice. The limited value of established prognostic markers requires the analysis of new molecular parameters of interest in predicting the prognosis of bladder cancer patients; in particular, the high-risk patient groups at risk of progression and recurrence. Over the past decade, there has been major progress elucidating of the molecular genetic and epigenetic changes leading to the development of transitional cell carcinoma. This review focuses on the recent advances of genetic and epigenetic aspects in bladder cancer, and emphasizes how molecular biology would be likely to affect the future therapies.

Loss of blood group A antigen expression in bladder cancer caused by allelic loss and/or methylation of the ABO gene

Loss of ABO blood group antigen expression has been reported in transitional cell carcinoma (TCC) of the bladder. Synthesis of the ABO blood group antigen was genetically determined by allelic variants of the ABO gene assigned on 9q34.1. We analyzed loss of heterozygosity (LOH) and promoter hypermethylation of the ABO gene in TCC and compared them with alterations of A antigen expression in TCC, dysplasia and normal urothelium. A total of 81 samples of TCC of the bladder obtained from transurethral resection (TUR) (n=44) and radical cystectomy (n=37) were examined. Expression of the A antigen was evaluated by immunohistochemical staining (IHC) using anti-A antigen monoclonal antibody. LOH of the ABO gene locus was examined by blunt-end single-strand DNA conformational polymorphism (SSCP) analysis using flouresence-based auto sequencer. Promoter hypermethylation of the ABO gene were examined by bisulfite PCR-SSCP (BiPS) analysis and/or methylation-specific PCR (MSP). Loss of A allele and/or hypermethylation were significantly associated with abnormal expression of the A antigen in cases undergoing TUR (P=0.02) and radical cystectomy (P=0.0005). For the analysis of the concomitant dysplasia in 23 cases with TCC of the bladder, the expression of the A antigen was maintained, regardless of the A allelic loss or methylation status in the tumor. In conclusion, A allelic loss and hypermethylation in the promoter region of the ABO gene showed significant correlation with reduction of A antigen expression in TCC, while the expression of the A antigen is maintained in concomitant dysplasia or normal urothelium, suggesting that loss of the ABO gene and/or its promoter hypermethylation is a specific marker for TCC.

Detection of methylated apoptosis-associated genes in urine sediments of bladder cancer patients

PURPOSE

There is increasing evidence for a fundamental role for epigenetic silencing of apoptotic pathways in cancer. Changes in DNA methylation can be detected with a high degree of sensitivity, so we used the MethyLight assay to determine how methylation patterns of apoptosis-associated genes change during bladder carcinogenesis and whether DNA methylation could be detected in urine sediments.

EXPERIMENTAL DESIGN

We analyzed the methylation status of the 5' regions of 12 apoptosis-associated genes (ARF, FADD, TNFRSF21, BAX, LITAF, DAPK, TMS-1, BCL2, RASSF1A, TERT, TNFRSF25, and EDNRB) in 18 bladder cancer cell lines, 127 bladder cancer samples, and 37 samples of adjacent normal bladder mucosa using the quantitative MethyLight assay. We also analyzed the methylation status in urine sediments of 20 cancer-free volunteers and 37 bladder cancer patients.

RESULTS

The 5' regions of DAPK, BCL2, TERT, RASSFIA, and TNFRSF25 showed significant increases in methylation levels when compared with nonmalignant adjacent tissue (P < or = 0.01). Methylation levels of BCL2 were significantly associated with tumor staging and grading (P < or = 0.01), whereas methylation levels of RASSF1A and ARF were only associated with tumor stage (P < or = 0.04), and TERT methylation and EDNRB methylation were predictors of tumor grade (P < or = 0.02). To investigate clinical usefulness for noninvasive bladder cancer detection, we further analyzed the methylation status of the markers in urine samples of patients with bladder cancer. Methylation of DAPK, BCL2, and TERT in urine sediment DNA from bladder cancer patients was detected in the majority of samples (78%), whereas they were unmethylated in the urine sediment DNA from age-matched cancer-free individuals.

CONCLUSIONS

Our results indicate that methylation of the 5' region of apoptosis-associated genes is a common finding in patients with bladder carcinoma. The ability to detect methylation not only in bladder tissue, but also in urine sediments, suggests that methylation markers are promising tools for noninvasive detection of bladder cancers. Our results also indicate that some methylation markers, such as those in regions of RASSF1A and TNFRSF25, might be of limited use for detection because they are also methylated in normal bladder tissues.

DNA HYPERMETHYLATION ON MULTIPLE CpG ISLANDS ASSOCIATED WITH INCREASED DNA METHYLTRANSFERASE DNMT1 PROTEIN EXPRESSION DURING MULTISTAGE UROTHELIAL CARCINOGENESIS

PURPOSE

We elucidated the significance of aberrant DNA methylation on multiple CpG islands and its correlation with DNA methyltransferase DNMT1 protein expression during urothelial carcinogenesis.

MATERIALS AND METHODS

We examined the DNA methylation status on multiple CpG islands by methylation specific polymerase chain reaction and combined bisulfite restriction enzyme analysis in 12 specimens of normal urothelium, 23 of noncancerous urothelium showing no remarkable histological changes obtained from patients with bladder cancer (NBC) and 70 of transitional cell carcinoma (TCC).

RESULTS

DNA methylation on CpG islands of the p16 (0%, 17% and 21%) and death-associated protein kinase (13%, 33% and 29%) genes, and methylated in tumor-2 (56%, 60% and 76%), 12 (0%, 6% and 30%), 25 (25%, 27% and 35%) and 31 (45%, 56% and 79%) clones was detected in normal urothelium, NBCs and TCCs, respectively. The incidence of concurrent DNA hypermethylation on 3 or more CpG islands in NBCs (38%) was significantly higher than that in normal urothelium (0%, p = 0.0455) and even higher in TCCs (59%, p = 0.0043). The incidence of the CpG island methylator phenotype in nonpapillary carcinomas (nodular invasive carcinomas and their precursors, ie flat carcinoma in situ, 71%) was significantly higher than in papillary carcinomas (40%, p = 0.0143). In all specimens examined concurrent DNA hypermethylation on 3 or more CpG islands significantly correlated with immunohistochemically evaluated DNMT1 protein over expression (p = 0.0167).

CONCLUSIONS

DNA hypermethylation on multiple CpG islands in association with DNMT1 protein over expression may participate in multistage urothelial carcinogenesis even at the precancerous stage and particularly in the development of nodular invasive carcinomas of the bladder.

Molecular biomarker in prostate cancer: the role of CpG island hypermethylation

CpG island hypermethylation may be one of the earliest somatic genome alterations to occur during the development of multiple cancers. Recently, aberrant methylation patterns for different tumors have been reported. We present a comprehensive review of the literature describing the role of CpG island hypermethylation of DNA from prostatic tissue and bodily fluids from men with prostate cancer. We reviewed the literature to evaluate CpG island hypermethylation in tissue and bodily fluids of men with primary and metastatic prostate cancer. Additionally, we reviewed the literature with respect to CpG island hypermethylation patterns in other urological malignancies. Using modern analytic methods, CpG island hypermethylation detection can be achieved. In men with prostate cancer, correlations between specific gene regulatory region hypermethylation analyses and Gleason score, pathologic stage and tumor recurrence have been demonstrated. CpG island hypermethylation may serve as a useful molecular biomarker for the detection and diagnosis of patients with prostate cancer.

Histone deacetylase inhibitors upregulate plakoglobin expression in bladder carcinoma cells and display antineoplastic activity in vitro and in vivo

Histone deacetylase inhibitors (HDACis) are emerging as a promising new class of anticancer agents displaying growth-inhibitory activity and low toxicity in vivo. In this study, we examined the effect of sodium butyrate (NaB) and trichostatin A (TSA) on the growth of human bladder carcinoma cell lines in culture and TSA on the growth of EJ and UM-UC-3 human bladder xenografts in nude mice. NaB and TSA suppressed the growth of bladder cell lines at millimolar (1.5-4.3 mM) and micromolar (0.03-0.33 microM) concentrations, respectively, inducing concentration-dependent cell death. Bladder carcinoma cells within the experimental panel displayed the phenotype of late-stage bladder lesions expressing N-cadherin in the absence of E-cadherin accompanied by low levels of plakoglobin expression. Exposure of these cells to HDACis resulted in upregulation of plakoglobin with no change in E-cadherin expression. A 2-hr exposure to TSA was the minimal time required to upregulate plakoglobin in cells with downregulation to baseline levels occurring within 24 hr following drug removal. In mice bearing EJ and UM-UC-3 bladder xenografts, TSA (500 microg/kg/day) caused suppression of tumor growth compared with mice receiving vehicle alone. A > 70% reduction in mean final tumor volume was recorded in both bladder xenograft models with no detectable toxicity. The results suggest that TSA inhibits bladder carcinoma cell growth and may be a useful, relatively nontoxic agent for consideration in the treatment of late-stage bladder tumors.

Expression and regulation of MIM (Missing In Metastasis), a novel putative metastasis suppressor gene, and MIM-B, in bladder cancer cell lines

It has been proposed that a 356 amino acid protein encoded by the MIM (Missing In Metastasis) gene on Chromosome 8q24.1, is a bladder cancer metastasis suppressor. Recently, Machesky and colleagues [Biochem. J. 371 (2003) 463] identified MIM-B, a 759 amino acid protein, of which the C-terminal 356 amino acids are almost identical to MIM. Importantly, PCR primers and Northern Blotting probes used in the studies of MIM in bladder cancer did not distinguish between sequences specific for MIM or MIM-B, thus the importance of either protein to bladder cancer remains unclear. We have used primer sequences specific for either MIM or MIM-B to explore the possible functional significance of MIM and MIM-B to bladder cancer cell behaviour. We have compared MIM and MIM-B mRNA levels in a non-tumourigenic, non-invasive, transformed uro-epithelial cell line versus 15 bladder cancer cell lines of differing in vitro invasive abilities, as well as in five cell lines clonally isolated from the BL17/2 bladder tumour cell line, whose in vitro and in vivo invasive abilities have been determined. MIM and MIM-B mRNA levels varied widely between cell lines. Down-regulation of MIM and MIM-B occurred in 6/15 (40%) lines but lines showing down-regulation differed between MIM and MIM-B. Reduced levels of MIM and MIM-B in BL17/2 were further reduced in 2/5 (40%) sublines (MIM and MIM-B). Importantly, there was no association between MIM or MIM-B expression and invasive behaviour in vivo or in vitro. Treatment of representative cell lines with 5-aza-2-deoxycytidine failed to induce MIM or MIM-B expression. Furthermore, there was no association between MIM or MIM-B mRNA levels and p53 functional status. Our data indicate that down-regulation of MIM and/or MIM-B expression can occur in bladder cancer cell lines but is not associated with increased invasive behaviour. Our data also suggest that in those cell lines with reduced levels of MIM and MIM-B mRNA, down-regulation is unlikely to be due to promoter hypermethylation or loss of p53 function.

Methylation of a CpG island within the uroplakin Ib promoter: a possible mechanism for loss of uroplakin Ib expression in bladder carcinoma

Uroplakin Ib is a structural protein on the surface of urothelial cells. Expression of uroplakin Ib mRNA is reduced or absent in many transitional cell carcinomas (TCCs) but molecular mechanisms underlying loss of expression remain to be determined. Analysis of the uroplakin Ib promoter identified a weak CpG island spanning the proximal promoter, exon 1, and the beginning of intron 1. This study examined the hypothesis that methylation of this CpG island regulates uroplakin Ib expression. Uroplakin Ib mRNA levels were determined by reverse transcription polymerase chain reaction and CpG methylation was assessed by bisulfite modification of DNA, PCR, and sequencing. A correlation was demonstrated in 15 TCC lines between uroplakin Ib mRNA expression and lack of CpG methylation. In support of a regulatory role for methylation, incubating uroplakin Ib-negative lines with 5-aza-2'-deoxycytidine reactivated uroplakin Ib mRNA expression. A trend between uroplakin Ib mRNA expression and CpG methylation was also observed in normal urothelium and bladder carcinomas. In particular, loss of uroplakin Ib expression correlated with methylation of a putative Sp1/NFkappaB binding motif. The data are consistent with the hypothesis that methylation of specific sites within the uroplakin Ib promoter may be an important factor in the loss of uroplakin Ib expression in TCCs.

Increased DNA Methyltransferase 1 Protein Expression in Human Transitional Cell Carcinoma of the Bladder

PURPOSE

DNA methylation is a key regulator of gene transcription and genomic stability, and alteration of DNA methylation is one of the most consistent epigenetic changes in human cancers. We elucidated the significance of aberrant protein expression of DNA methyltransferase (DNMT) 1, a major enzyme involved in the determination of genomic methylation patterns, during human urothelial carcinogenesis.

MATERIALS AND METHODS

A total of 61 samples of normal urothelium, 89 noncancerous urothelium samples showing no remarkable histological changes from patients with bladder cancer (NBCs), 78 dysplastic urothelium samples and 174 transitional cell carcinoma samples (TCCs) were subjected to immunohistochemical analysis for DNMT1.

RESULTS

The incidence of nuclear DNMT1 immunoreactivity in NBCs (65%) was significantly higher than in normal urothelium (20%, p <0.0001) and the incidence was even higher in dysplastic urothelium samples (84%, p = 0.0017). The incidence of nuclear DNMT1 immunoreactivity was 87% in TCCs and the intensity of nuclear immunoreactivity was markedly increased in TCCs compared with that in dysplastic urothelium samples. DNMT1 expression levels had already increased in NBCs in which the proliferating cell nuclear antigen labeling index had not yet increased. Increased DNMT1 protein expression correlated significantly with histological grade (p <0.0001). DNMT1 protein expression was higher in nonpapillary tumors (p = 0.0001), especially flat carcinoma in situ, than in papillary tumors.

CONCLUSIONS

Progressively increasing expression of DNMT1 protein is not entirely a secondary result of increased cell proliferative activity, but rather it is associated with urothelial carcinogenesis even during the precancerous stages. In particular, it is associated with the development of flat carcinoma in situ, which is considered to be a precursor of nodular invasive carcinoma of the bladder.