Gene expression profiling of noninvasive primary urothelial tumours using microarrays

Unleashing the potential of 5-Aminolevulinic acid: Unveiling a promising target for cancer diagnosis and treatment beyond photodynamic therapy

The therapeutic properties of 5-aminolevulinic acid (5-ALA) have been extensively studied for cancer detection and treatment using photodynamic therapy (PDT). When administered externally, 5-ALA is converted to protoporphyrin IX (PpIX) in cancer cells, which generates reactive oxygen species (ROS) upon exposure to light. This process enables targeted cell death induction and cancer detection. Given the highly conserved nature of heme biosynthesis over billions of years, we hypothesized that natural mechanisms might exist to prevent excessive accumulation of PpIX or heme resulting from 5-ALA overload. Therefore, we anticipated alterations in protein expression profiles upon exogenous administration of 5-ALA. To understand cellular responses to 5-ALA, we investigated protein expression changes and identified OR1B1 as a promising target in bladder, prostate, lung, and cervical cancer cells. OR1B1 expression was observed only with 5-ALA and ferrous chloride, highlighting the central role of heme in this discovery. Immunofluorescence and electron microscopy confirmed OR1B1's sub-cellular localization. These findings suggest that 5-ALA transformation in cancer cells and OR1B1 expression have potential for enhancing cancer detection and developing alternative treatments, including immunotherapy. This approach overcomes the limitations of PDT and opens new avenues for effective and targeted cancer interventions.

Core promoter mutation contributes to abnormal gene expression in bladder cancer

Background

Bladder cancer is one of the most mortal cancers. Bladder cancer has distinct gene expression signature, highlighting altered gene expression plays important roles in bladder cancer etiology. However, the mechanism for how the regulatory disorder causes the altered expression in bladder cancer remains elusive. Core promoter controls transcriptional initiation. We hypothesized that mutation in core promoter abnormality could cause abnormal transcriptional initiation thereby the altered gene expression in bladder cancer.

Methods

In this study, we performed a genome-wide characterization of core promoter mutation in 77 Spanish bladder cancer cases.

Results

We identified 69 recurrent somatic mutations in 61 core promoters of 62 genes and 28 recurrent germline mutations in 20 core promoters of 21 genes, including TERT, the only gene known with core promoter mutation in bladder cancer, and many oncogenes and tumor suppressors. From the RNA-seq data from bladder cancer, we observed  altered expression of the core promoter-mutated genes. We further validated the effects of core promoter mutation on gene expression by using luciferase reporter gene assay. We also identified potential drugs targeting the core promoter-mutated genes.

Conclusions

Data from our study highlights that core promoter mutation contributes to bladder cancer development through altering gene expression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09178-z.

Evaluation of hTERT, KRT7, and survivin in urine for noninvasive detection of bladder cancer using real-time PCR

Background

Transitional cell carcinoma (TCC) of the bladder is the second most common genitourinary malignancy. Because of the low sensitivity of urinary cytology and the invasiveness and expense of frequent cystoscopies for the detection of low-grade superficial lesions, we aim to establish a sensitive molecular approach to detect bladder cancer noninvasively.

Methods

Voided urine samples were collected from 80 patients with bladder cancer at the time of diagnosis, in addition to 30 patients with non-bladder cancer urological diseases and 20 healthy volunteers. The level of hTERT, KRT7, and survivin (SVV) mRNAs were analyzed using a qRT-PCR assay.

Results

The optimal threshold values for hTERT, KRT7, and SVV in urine were calculated by ROC curves analysis. The overall sensitivity was 81.3%, 91.3%, and 68.8% for hTERT, KRT7, and SVV, respectively, which were significantly higher than urine cytology (22.2%, p < 0.001). A higher positive ratio was obtained using multi-marker detection in comparison to single marker detection. The combined use of markers increased the sensitivity of cytology from 22.2 to 100%. In contrast with the urine cytology method, the sensitivity of these biomarkers was not correlated with the grades and stages of the bladder tumors.

Conclusions

Our data indicate that urinary hTERT, KRT7, and SVV have superior sensitivities over cytology. The combined use of these markers offers a powerful potential assay and promising tool for a sensitive, noninvasive, and highly specific diagnostic method and follow-up of low-grade TCC of the bladder.

A potential panel of five mRNAs in urinary extracellular vesicles for the detection of bladder cancer

Background

Extracellular vesicles (EVs) have showed promising potential in liquid biopsy of cancer. In present study, we evaluate the feasibility to diagnose bladder cancer using EVs RNA markers identified from public tissue RNA sequencing data.

Methods

We used urine samples from a cohort of population with suspected bladder cancer. Disease status (i.e., primary or recurrent bladder cancer) was diagnosed by cystoscopy. A prediction model including the expression of multiple RNAs in urinary EVs were developed in training cohort (n=368, 126 bladder cancer and 242 negative controls). The performance of optimal model (ExoPanel) consists of five mRNAs (MYBL2, TK1, UBE2C, KRT7, S100A2) was further assessed by a validation cohort (n=155, 56 bladder cancer and 99 negative controls).

Results

The performance of ExoPanel in training cohort was AUC 0.7759 (95% CI: 0.7259–0.8260), NPV 90.34% (95% CI: 84.04–94.42%), SN 88.89% (95% CI: 81.75–93.57%), and SP 54.13% (95% CI: 47.63–60.50%) respectively. In the validation cohort, the performance of this model was AUC 0.8402 (95% CI: 0.7690–0.9114), NPV 90.91% (95% CI: 79.29–96.60%), SN 91.07% (95% CI: 79.63–96.67%), and SP 50.51% (95% CI: 40.34–60.63%). Using this model, it is possible to rule out a significant number of non cancer patients, thus reduce the unnecessary operation of cystoscopy.

Conclusions

We discovered a panel of five mRNAs, and evaluated its potential to facilitate bladder cancer diagnosis by analyzing their expression in urinary EVs.

Differential gene expression identifies KRT7 and MUC1 as potential metastasis-specific targets in sarcoma

BACKGROUND

Despite numerous discoveries regarding the molecular genesis and progression of primary cancers, the biology of metastasis remains poorly understood. Compared to very large numbers of circulating tumor cells that are now known to accompany nearly all cancers, a relatively limited number of lesions actually develop in most patients with metastases. We hypothesized that phenotypic changes driven by differential gene expression in a finite subpopulation of tumor cells render those cells capable of metastasis and sought to identify key pathways through analysis of gene expression in primary and metastatic lesions from the same patients.

METHODS

We compared whole-genome expression in 4 matched samples of primary and metastatic sarcoma, then evaluated candidate genes with differential expression via quantitative PCR in 30 additional matched sets, tumor tissue immunostaining, siRNA loss-of-function in a sarcoma cell migration assay, and clinical correlation with overall and disease-free survival after metastasectomy.

RESULTS

Comparison of microarray signals identified differential expression of cell adhesion genes, including upregulation of KRT7 and MUC1 in metastases; KRT7 and MUC1 upregulation was confirmed in 22 (73%) and 20 (67%) matched sets of metastatic/primary tumors, respectively. Silencing of KRT7 and MUC1 via targeted siRNAs suppressed sarcoma cell migration in vitro, and a significant correlation (two-sided) was observed between both KRT7 and MUC1 expression in metastases and overall patient survival.

CONCLUSION

KRT7 and MUC1 may play a significant role in enabling sarcoma metastasis, and they may therefore be important prognostic biomarkers as well as potential targets for therapeutic prevention of metastasis.

Upregulation of NDRG1 predicts poor outcome and facilitates disease progression by influencing the EMT process in bladder cancer

N-myc downstream regulated gene 1 (NDRG1) is an intracellular protein involved in cell differentiation and was recently reported to exert various effects in several cancers. However, its expression and role in bladder cancer remain unclear. Our study enrolled 100 bladder cancer patients to detect NDRG1 expression in tumour tissues by immunohistochemistry. Correlations between NDRG1 expression and clinical factors were analysed. An NDRG1 overexpression plasmid and NDRG1 siRNAs were transfected into bladder cancer cell lines. Cell biological behaviours were assessed by CCK-8, flow cytometry, wound healing and Transwell assays. Additionally, the influence of NDRG1 on epithelial-mesenchymal transition (EMT) was investigated by western blotting and real-time PCR. NDRG1 expression in urine from bladder cancer patients was examined by ELISA. NDRG1 protein levels were significantly increased in bladder cancer patients and correlated with tumour stage (p = 0.025), lymph node metastasis (p = 0.034) and overall survival (p = 0.016). Patients with high NDRG1 expression had poorer outcomes than those with low NDRG1 expression. NDRG1 overexpression was associated with increased cell proliferation, migration, and invasion and decreased apoptotic cell numbers; NDRG1 knockdown resulted in the inverse effects. Moreover, upregulated NDRG1 expression was associated with downregulated Cytokeratin 7 and Claudin-1 expression and upregulated N-cad, β-catenin and slug expression. Downregulated NDRG1 expression was associated with the inverse effects. Urine protein levels could distinguish bladder cancer patients from healthy controls, with an area under the curve of 0.909. NDRG1 promoted EMT in bladder cancer and could be an effective diagnostic and prognostic biomarker in bladder cancer patients.

Over forty years of bladder cancer glycobiology: Where do glycans stand facing precision oncology?

The high molecular heterogeneity of bladder tumours is responsible for significant variations in disease course, as well as elevated recurrence and progression rates, thereby hampering the introduction of more effective targeted therapeutics. The implementation of precision oncology settings supported by robust molecular models for individualization of patient management is warranted. This effort requires a comprehensive integration of large sets of panomics data that is yet to be fully achieved. Contributing to this goal, over 40 years of bladder cancer glycobiology have disclosed a plethora of cancer-specific glycans and glycoconjugates (glycoproteins, glycolipids, proteoglycans) accompanying disease progressions and dissemination. This review comprehensively addresses the main structural findings in the field and consequent biological and clinical implications. Given the cell surface and secreted nature of these molecules, we further discuss their potential for non-invasive detection and therapeutic development. Moreover, we highlight novel mass-spectrometry-based high-throughput analytical and bioinformatics tools to interrogate the glycome in the postgenomic era. Ultimately, we outline a roadmap to guide future developments in glycomics envisaging clinical implementation.

E-cadherin downregulation sensitizes PTEN-mutant tumors to PI3Kβ silencing

Alterations in phosphatidylinositol 3-kinase (PI3K) and in PTEN (phosphatase and tensin homolog), the negative regulator of the PI3K pathway, are found in nearly half of human tumors. As PI3Kβ, the main isoform activated in PTEN-mutant tumors, has kinase-dependent and -independent activities, we compared the effects of depleting vs. drug-inhibiting PI3Kβ kinase activity in a collection of diverse tumor types and in a set of bladder carcinoma cell lines grown as xenografts in mice. PI3Kβ depletion (by intratumor injection of PIK3CB siRNA) induced apoptosis and triggered regression of PTEN-mutant tumors more efficiently than PI3Kβ inhibition. A small proportion of these tumors was resistant to PI3Kβ downregulation; we analyzed what determined resistance in these cases. Using add-back experiments, we show that both PTEN mutation and low E-cadherin expression are necessary for PI3Kβ dependence. In bladder carcinoma, loss of E-cadherin expression coincides with N-cadherin upregulation. We found that PI3Kβ associated with N-cadherin and that PIK3CB depletion selectively disrupted N-cadherin cell adhesions in PTEN-mutant bladder carcinoma. These results support the use of PIK3CB interfering RNA as a therapeutic approach for high-risk bladder cancers that show E-cadherin loss and express mutant PTEN.

Detection and Clinical Significance of Circulating Tumor Cells in Patients Undergoing Radical Cystectomy for Urothelial Bladder Cancer

INTRODUCTION

Estimation of prognosis is patients undergoing radical cystectomy is often unreliable, as occult disease remains undetected by conventional diagnostic tools. The purpose of this study was to evaluate the feasibility and the clinical significance of a polymerase chain reaction assay to detect cytokeratin 7 (CK7) mRNA expression in peripheral blood cells of patients undergoing radical cystectomy for clinically nonmetastatic bladder cancer.

PATIENTS AND METHODS

From 2005 to 2009, 59 patients undergoing radical cystectomy and pelvic lymph node dissection were prospectively investigated. Peripheral blood was collected prior to surgery, and a nested polymerase chain reaction assay was developed to identify patients with circulating cells expressing CK7 mRNA. Preoperative, histopathologic data and clinical outcome were compared with CK7 findings.

RESULTS

CK7 expression was detected in 23 (38.9%) of 59 patients and correlated to T stage and lymph node status. After a median follow-up of 42 months, 29 patients experienced a recurrence, whereas 36 died. The presence of CK7-positive cells was significantly associated with an increased risk for recurrence and decreased survival as compared with patients who were CK7-negative (P < .001 and P < .001, respectively; hazard ratios of 8.77 and 5.2 for recurrence and overall death, respectively). The detection of CK7-positive cells was an independent predictor of recurrence and death in a multivariable analysis.

CONCLUSION

The detection of CK7 mRNA in the circulating cells of patients undergoing radical cystectomy for urothelial cancer identifies those with significantly increased risk of cancer recurrence and death.

A Systematic Review of the Diagnostic and Prognostic Value of Urinary Protein Biomarkers in Urothelial Bladder Cancer

For over 80 years, cystoscopy has remained the gold-standard for detecting tumours of the urinary bladder. Since bladder tumours have a tendency to recur and progress, many patients are subjected to repeated cystoscopies during long-term surveillance, with the procedure being both unpleasant for the patient and expensive for healthcare providers. The identification and validation of bladder tumour specific molecular markers in urine could enable tumour detection and reduce reliance on cystoscopy, and numerous classes of biomarkers have been studied. Proteins represent the most intensively studied class of biomolecule in this setting. As an aid to researchers searching for better urinary biomarkers, we report a comprehensive systematic review of the literature and a searchable database of proteins that have been investigated to date. Our objective was to classify these proteins as: 1) those with robustly characterised sensitivity and specificity for bladder cancer detection; 2) those that show potential but further investigation is required; 3) those unlikely to warrant further investigation; and 4) those investigated as prognostic markers. This work should help to prioritise certain biomarkers for rigorous validation, whilst preventing wasted effort on proteins that have shown no association whatsoever with the disease, or only modest biomarker performance despite large-scale efforts at validation.

A Nomogram Derived by Combination of Demographic and Biomarker Data Improves the Noninvasive Evaluation of Patients at Risk for Bladder Cancer

BACKGROUND

Improvements in the noninvasive clinical evaluation of patients at risk for bladder cancer would be of benefit both to individuals and to health care systems. We investigated the potential utility of a hybrid nomogram that combined key demographic features with the results of a multiplex urinary biomarker assay in hopes of identifying patients at risk of harboring bladder cancer.

METHODS

Logistic regression analysis was used to model the probability of bladder cancer burden in a cohort of 686 subjects (394 with bladder cancer) using key demographic features alone, biomarker data alone, and the combination of demographic features and key biomarker data. We examined discrimination, calibration, and decision curve analysis techniques to evaluate prediction model performance.

RESULTS

Area under the receiver operating characteristic curve (AUC) analyses revealed that demographic features alone predicted tumor burden with an accuracy of 0.806 [95% confidence interval (CI), 0.76-0.85], while biomarker data had an accuracy of 0.835 (95% CI, 0.80-0.87). The addition of molecular data into the nomogram improved the predictive performance to 0.891 (95% CI, 0.86-0.92). Decision curve analyses showed that the hybrid nomogram performed better than demographic or biomarker data alone.

CONCLUSION

A nomogram construction strategy that combines key demographic features with biomarker data may facilitate the accurate, noninvasive evaluation of patients at risk of harboring bladder cancer. Further research is needed to evaluate the bladder cancer risk nomogram for potential clinical utility.

IMPACT

The application of such a nomogram may better inform the decision to perform invasive diagnostic procedures. Cancer Epidemiol Biomarkers Prev; 25(9); 1361-6. ©2016 AACR.

Molecular substratification of bladder cancer: moving towards individualized patient management

Despite advances in surgical techniques, perioperative therapies and postoperative management, outcomes for patients with bladder cancer have largely remained unchanged. Current management of bladder cancer still relies on pathologic staging that does not always reflect the risk for an individual patient. Studies assessing molecular alterations in individual tumors are offering insights into the myriad of cellular pathways that are deregulated in bladder tumorigenesis and progression. Alterations in pathways involved in cell-cycle regulation, apoptosis, cell signaling, angiogenesis and tumor-cell invasion have been shown to influence disease behavior. High-throughput assays are now allowing multiplexed assessment of biomarker alterations, thereby enabling characterization of novel molecular subtypes of bladder cancer. Such approaches have also been used for discovery and validation of robust prognostic molecular signatures. The future of bladder cancer management will rely on the use of validated multimarker panels for risk stratification, optimal surgical management, and theranostic strategies to identify and target specific alterations in individual tumors.

Polycomb Repressor Complex 1 Member, BMI1 Contributes to Urothelial Tumorigenesis through p16-Independent Mechanisms

Urothelial carcinoma (UC) causes significant morbidity and remains the most expensive cancer to treat because of the need for repeated resections and lifelong monitoring for patients with non-muscle-invasive bladder cancer (NMIBC). Novel therapeutics and stratification approaches are needed to improve the outlook for both NMIBC and muscle-invasive bladder cancer. We investigated the expression and effects of B Lymphoma Mo-MLV Insertion Region 1 (BMI1) in UC. BMI1 was found to be overexpressed in most UC cell lines and primary tumors by quantitative real-time polymerase chain reaction and immunohistochemistry. In contrast to some previous reports, no association with tumor stage or grade was observed in two independent tumor panels. Furthermore, upregulation of BMI1 was detected in premalignant bladder lesions, suggesting a role early in tumorigenesis. BMI1 is not located within a common region of genomic amplification in UC. The CDKN2A locus (which encodes the p16 tumor suppressor gene) is a transcriptional target of BMI1 in some cellular contexts. In UC cell lines and primary tissues, no correlation between BMI1 and p16 expression was observed. Retroviral-mediated overexpression of BMI1 immortalized normal human urothelial cells (NHUC) in vitro and was associated with induction of telomerase activity, bypass of senescence, and repression of differentiation. The effects of BMI1 on gene expression were identified by expression microarray analysis of NHUC-BMI1. Metacore analysis of the gene expression profile implicated downstream effects of BMI1 on α4/β1 integrin-mediated adhesion, cytoskeleton remodeling, and CREB1-mediated transcription.

Cadmium as a possible cause of bladder cancer: a review of accumulated evidence

Bladder cancer is a significant disease, the rates of which have increased over the few last years. However, its etiology remains as yet undefined. Cadmium, a widespread environmental carcinogen that has received considerable interest, presents evidence as a possible cause of bladder cancer. A literature review was conducted from the years 1984-2013 to study the accumulated evidence for cadmium as a possible cause of bladder cancer, including routes of cadmium exposure, accumulation, toxicity, carcinogenicity, and evidence from epidemiological and experimental studies. Special reference is devoted to cadmium nephrotoxicity, which illustrates how cadmium exerts its effects on the transitional epithelium of the urinary tract. Mechanisms of carcinogenesis are discussed. The effects of cadmium on gene expression in urothelial cells exposed to cadmium are also addressed. Despite different methodologies, several epidemiologic and nephrotoxicity studies of cadmium indicate that occupational exposure to cadmium is associated with increased risk of bladder cancer and provide additional evidence that cadmium is a potential toxic element in urothelial cells. In vitro studies provide further evidence that cadmium is involved in urothelial carcinogenesis. Animal studies encounter several problems such as morphology differences between species. Among the complex mechanisms of cadmium carcinogenesis, gene expression deregulation is the subject of recent studies on bladder cadmium-induced carcinogenesis. Further research, however, will be required to promise a better understanding of the mechanisms underlying cadmium carcinogenesis and to establish the precise role of cadmium in this important malignancy.

Soluble CD138/Syndecan-1 Increases in the Sera of Patients with Moderately Differentiated Bladder Cancer

BACKGROUND

CD138/Syndecan-1 (Sdc-1) is expressed on the tumor and stromal cells of invasive bladder carcinoma. CD138/Sdc-1 shedding from the cell surface is associated with the invasive phenotype in lung and breast cancers.

PATIENTS AND METHODS

Soluble CD138/Sdc-1 was measured in the sera of 86 bladder cancer patients and 57 healthy individuals by a commercial ELISA assay.

RESULTS

Soluble Sdc-1 was increased in the sera of patients with bladder cancer (138.42 ± 81.85 vs. 86.48 ± 82.58 ng/ml, p = 0.0003). Patients aged over 70 years had higher levels of CD138/Sdc-1 in their sera (159.7 ± 15.77 vs. 124.5 ± 9.99 ng/ml, p = 0.025), and soluble Sdc-1 levels were higher in the sera of patients with moderately differentiated tumors compared to poorly differentiated ones (170.47 ± 85.06 vs. 101.79 ± 68.24 ng/ml, p = 0.01). The soluble Sdc-1 level was higher in muscle-invasive (154.45 ± 83.60 vs. 89.9 ± 55.02 ng/ml) but not lymphatic-invasive (106.25 ± 52.10 vs. 123.43 ± 63.76 ng/ml) tumors (p = 0.027 and 0.45, respectively). A non-significant trend of soluble Sdc-1 increase in the sera of male patients compared to female patients was observed (145.38 ± 85.47 vs. 110.20 ± 59.04 ng/ml, p = 0.054).

CONCLUSION

The elevated levels of soluble CD138/Sdc-1 in older bladder cancer patients and those with muscular invasion sheds some light on the mechanisms of the disease invasion.

External validation of a multiplex urinary protein panel for the detection of bladder cancer in a multicenter cohort

BACKGROUND

Because of the faltering sensitivity and/or specificity, urine-based assays currently have a limited role in the management of patients with bladder cancer. The aim of this study was to externally validate our previously reported protein biomarker panel from multiple sites in the United States and Europe.

METHODS

This multicenter external validation study included a total of 320 subjects (bladder cancer = 183). The 10 biomarkers (IL8, MMP9, MMP10, SERPINA1, VEGFA, ANG, CA9, APOE, SDC1, and SERPINE1) were measured using commercial ELISA assays in an external laboratory. The diagnostic performance of the biomarker panel was assessed using receiver operator curves (ROC) and descriptive statistical values.

RESULTS

Utilizing the combination of all 10 biomarkers, the area under the ROC for the diagnostic panel was noted to be 0.847 (95% confidence interval, 0.796-0.899), outperforming any single biomarker. The multiplex assay at optimal cutoff value achieved an overall sensitivity of 0.79, specificity of 0.79, positive prediction value of 0.73, and negative prediction value of 0.84 for bladder cancer classification. Sensitivity values of the diagnostic panel for high-grade bladder cancer, low-grade bladder cancer, muscle invasive bladder cancer, and non-muscle invasive bladder cancer were 0.81, 0.90, 0.95, and 0.77, respectively.

CONCLUSIONS

Urinary levels of the biomarker panel enabled discrimination of patients with bladder cancer and controls, and the levels of biomarker subsets were associated with advancing tumor grade and stage.

IMPACT

If proven to be reliable, urinary diagnostic biomarker assays can detect bladder cancer in a timely manner such that the patient can expect improvements in overall survival and quality of life.

Prognostic significance of heme oxygenase-1, S100 calcium-binding protein A4, and syndecan-1 expression in primary non-muscle-invasive bladder cancer

We investigated the prognostic significance of heme oxygenase-1 (HO-1), S100 calcium-binding protein A4 (S100A4), and syndecan-1 (SYND1) expression in patients with primary non-muscle-invasive bladder cancer (NMIBC). Immunohistochemical studies were performed on tissue specimens from 109 patients diagnosed with primary NMIBC following complete transurethral resection, with the expression dichotomized as negative/mild ("low") versus moderate/strong ("high") according to scores based on staining area and intensity. The effect of each biomarker on recurrence-free survival (RFS) and progression-free survival (PFS) was analyzed. The predictive accuracy for RFS and PFS in multivariate Cox regression models with or without (the baseline model) biomarkers was estimated using the Harrell concordance index. High HO-1, S100A4, and SYND1 expressions were observed in 33.0%, 36.7%, and 63.3% cases, respectively. High HO-1 and S100A4 expressions were significantly associated with various adverse pathological characteristics (high T stage and grade); SYND1 expression was inversely correlated with these characteristics (all, P < .05). In the baseline multivariate model, multifocality, intravesical therapy, and T stage were significant predictors for RFS, whereas intravesical therapy and T stage had marginal statistical significance in predicting PFS. In the multivariate model with the biomarkers, the 3 biomarkers were significant predictors for RFS; and HO-1 expression was a significant predictor for PFS. Addition of the 3 biomarkers to the baseline model significantly increased the predictive accuracy for RFS from 0.754 to 0.828 (P = .043). Our findings suggest that HO-1, S100A4, and SYND1 expressions have prognostic value in primary NMIBC; thus, their evaluation might be useful for determining treatment strategies.

Clinical implications in the shift of syndecan-1 expression from the cell membrane to the cytoplasm in bladder cancer

BACKGROUND

To determine the diagnostic and prognostic capability of urinary and tumoral syndecan-1 (SDC-1) levels in patients with cancer of the urinary bladder.

METHODS

SDC-1 levels were quantitated by enzyme-linked immunosorbent assay (ELISA) in 308 subjects (102 cancer subjects and 206 non-cancer subjects) to assess its diagnostic capabilities in voided urine. The performance of SDC-1 was evaluated using the area under the curve of a receiver operating characteristic curve. In addition, immunohistochemical (IHC) staining assessed SDC-1 protein expression in 193 bladder specimens (185 cancer subjects and 8 non-cancer subjects). Outcomes were correlated to SDC-1 levels.

RESULTS

Mean urinary levels of SDC-1 did not differ between the cancer subjects and the non-cancer subjects, however, the mean urinary levels of SDC-1 were reduced in high-grade compared to low-grade disease (p < 0.0001), and in muscle invasive bladder cancer (MIBC) compared to non-muscle invasive bladder cancer (NMIBC) (p = 0.005). Correspondingly, preliminary data note a shift from a membranous cellular localization of SDC-1 in normal tissue, low-grade tumors and NMIBC, to a distinctly cytoplasmic localization in high-grade tumors and MIBC was observed in tissue specimens.

CONCLUSION

Alone urinary SDC-1 may not be a diagnostic biomarker for bladder cancer, but its urinary levels and cellular localization were associated with the differentiation status of patients with bladder tumors. Further studies are warranted to define the potential role for SDC-1 in bladder cancer progression.

Microarray gene expression profiling and analysis of bladder cancer supports the sub-classification of T1 tumours into T1a and T1b stages

OBJECTIVE

To try and identify a molecular signature for pathological staging and/or grading. through microarray analysis.

PATIENTS AND METHODS

We performed a prospective multicentre study between September 2007 and May 2008 that included 108 bladder tumours (45 pTa, 35 pT1 and 28>pT1). Microarray analysis was performed using Agilent Technologies Human Whole Genome 4 × 44K oligonucleotide microarrays (Agilent, Santa Clara, CA, USA). A 'dual colour' method was used vs a reference pool of tumours. From the lists of genes provided by the Biometric Research Branch class comparison analyses, we validated the microarray results of 38 selected differentially expressed genes using reverse transcriptase quantitative PCR in another bladder tumour cohort (n = 95).

RESULTS

The cluster 'superficial vs invasive stage' correctly classified 92.9% of invasive stages and 66.3% of superficial stages. Among the superficial tumours, the cluster analysis showed that pT1b tumours were closer to invasive stages than pT1a tumours. We also found molecular differences between low and high grade superficial tumours, but these differences were less well defined than the difference observed for staging.

CONCLUSIONS

We confirmed that the histopathological classification into subgroups pTa, pT1a and pT1b can be translated into a molecular signature with a continuous progression of deregulation (overexpression or repression of these genes) from superficial (pTa) to more invasive (pT1a then b) stages.

Prognostic value of cell-cycle regulation biomarkers in bladder cancer

The determination of prognosis in bladder cancer is currently based on staging methods that rely primarily on the pathological stage of a tumor with limited objective correlates. The development and progression of bladder cancer involve alterations in several cellular pathways. Dysregulation in markers associated with cell-cycle regulation has been the most extensively examined molecular aberration in this cancer. Individual alterations of these markers have been associated with disease outcome, with several observations suggesting that their prognostic potential is independent of pathological stage. While many individual molecules in the cell growth receptor signaling, p53, and retinoblastoma (Rb) pathways have been identified, there is a general lack of consensus on which markers can be adopted in the clinical setting. More recent studies have suggested that the combination of markers as concise panels may be more beneficial in determining the degree of aggressiveness of a given tumor and its impending outcome than individual markers alone. This review will discuss alterations in molecules within pathways controlling cell-cycle regulation in the context of bladder cancer, and their impact on patient outcome when examined individually and in combination.

Analysis of molecular intra-patient variation and delineation of a prognostic 12-gene signature in non-muscle invasive bladder cancer; technology transfer from microarrays to PCR

Background:

Multiple clinical risk factors and genetic profiles have been demonstrated to predict progression of non-muscle invasive bladder cancer; however, no easily clinical applicable gene signature has been developed to predict disease progression independent of disease stage and grade.

Methods:

We measured the intra-patient variation of an 88-gene progression signature using 39 metachronous tumours from 17 patients. For delineation of the optimal quantitative reverse transcriptase PCR panel of markers, we used 115 tumour samples from patients in Denmark, Sweden, UK and Spain.

Results:

Analysis of intra-patient variation of the molecular markers showed 71% similar classification results. A final panel of 12 genes was selected, showing significant correlation with outcome. In multivariate Cox regression analysis, we found that the 12-gene signature was an independent prognostic factor (hazard ratio=7.4 (95% confidence interval: 3.4–15.9), P<0.001) when adjusting for stage, grade and treatment. Independent validation of the 12-gene panel and the determined cut-off values is needed and ongoing.

Conclusion:

Intra-patient marker variation in metachronous tumours is present. Therefore, to increase test sensitivity, it may be necessary to test several metachronous tumours from a patient’s disease course. A PCR-based 12-gene signature significantly predicts disease progression in patients with non-muscle invasive bladder cancer.

IL-8 as a urinary biomarker for the detection of bladder cancer

Background

Current urine-based assays for bladder cancer (BCa) diagnosis lack accuracy, so the search for improved biomarkers continues. Through genomic and proteomic profiling of urine, we have identified a panel of biomarkers associated with the presence of BCa. In this study, we evaluated the utility of three of these biomarkers, interleukin 8 (IL-8), Matrix metallopeptidase 9 (MMP-9) and Syndecan in the diagnosis of BCa through urinalysis.

Methods

Voided urines from 127 subjects, cancer subjects (n = 64), non-cancer subjects (n = 63) were analyzed. The protein concentrations of IL-8, MMP-9, and Syndecan were assessed by enzyme-linked immunosorbent assay (ELISA). Data were also compared to a commercial ELISA-based BCa detection assay (BTA-Trak©) and urinary cytology. We used the area under the curve of a receiver operating characteristic (AUROC) to compare the performance of each biomarker.

Results

Urinary protein concentrations of IL-8, MMP-9 and BTA were significantly elevated in BCa subjects. Of the experimental markers compared to BTA-Trak©, IL-8 was the most prominent marker (AUC; 0.79; 95% confidence interval [CI], 0.72-0.86). Multivariate regression analysis revealed that only IL-8 (OR; 1.51; 95% CI, 1.16-1.97, p = 0.002) was an independent factor for the detection of BCa.

Conclusions

These results suggest that the measurement of IL-8 in voided urinary samples may have utility for urine-based detection of BCa. These findings need to be confirmed in a larger, prospective cohort.

Bladder expression of CD cell surface antigens and cell-type-specific transcriptomes

Many cell types have no known functional attributes. In the bladder and prostate, basal epithelial and stromal cells appear similar in cytomorphology and share several cell surface markers. Their total gene expression (transcriptome) should provide a clear measure of the extent to which they are alike functionally. Since urologic stromal cells are known to mediate organ-specific tissue formation, these cells in cancers might exhibit aberrant gene expression affecting their function. For transcriptomes, cluster designation (CD) antigens have been identified for cell sorting. The sorted cell populations can be analyzed by DNA microarrays. Various bladder cell types have unique complements of CD molecules. CD9(+) urothelial, CD104(+) basal and CD13(+) stromal cells of the lamina propria were therefore analyzed, as were CD9(+) cancer and CD13(+) cancer-associated stromal cells. The transcriptome datasets were compared by principal components analysis for relatedness between cell types; those with similarity in gene expression indicated similar function. Although bladder and prostate basal cells shared CD markers such as CD104, CD44 and CD49f, they differed in overall gene expression. Basal cells also lacked stem cell gene expression. The bladder luminal and stromal transcriptomes were distinct from their prostate counterparts. In bladder cancer, not only the urothelial but also the stromal cells showed gene expression alteration. The cancer process in both might thus involve defective stromal signaling. These cell-type transcriptomes provide a means to monitor in vitro models in which various CD-isolated cell types can be combined to study bladder differentiation and bladder tumor development based on cell-cell interaction.

Comparison of expression patterns of keratin 6, 7, 16, 17, and 19 within multiple independent isolates of As(+3)- and Cd (+2)-induced bladder cancer : keratin 6, 7, 16, 17, and 19 in bladder cancer

This laboratory has generated a series of seven cadmium (Cd(+2))- and six arsenite (As(+3))-transformed urothelial cancer cell lines by exposure of parental UROtsa cells to each agent under similar conditions of exposure. In this study, the seven Cd(+2)-transformed cell lines were characterized for the expression of keratin 6, 16, and 17 while the six As(+3) cell lines were assessed for the expression of keratin 7 and 19. The results showed that the series of Cd(+2)-transformed cell lines and their respective transplants all had expression of keratin 6, 16, and 17 mRNA and protein. The expression of keratin 6, 16, and 17 was also correlated with areas of the urothelial tumor cells that had undergone squamous differentiation. The results also showed that four of the six As(+3)-transformed cell lines had expression of keratin 7 and 19 mRNA and protein and produced subcutaneous tumors with intense focal staining for keratin 7 and 19. The other two As(+3)-transformed cell lines had very low expression of keratin 7 mRNA and protein and produced subcutaneous tumors having no immunoreactivity for keratin 7; although keratin 19 expression was still present. The peritoneal tumors produced by one of these two cell lines regained expression of keratin 7 protein. The present results, coupled with previous studies, indicate that malignant transformation of UROtsa cells by Cd(+2) or As(+3) produce similar patterns of keratin 6, 7, 16, 17, and 19 in the resulting series of cell lines and their respective tumors.

Molecular markers in transitional cell carcinoma of the bladder: New insights into mechanisms and prognosis

Urothelial carcinoma is potentially life-threatening and expensive to treat since for many patients, the diagnosis entails a lifetime of surveillance to detect recurrent disease. Advancements in technology have provided an understanding of the molecular mechanisms of carcinogenesis and defined distinct pathways in tumorigenesis and progression. At the molecular level, urothelial carcinoma is being seen as a disease with distinct pathways of carcinogenesis and progression and thus markers of these processes should be used as both diagnostics and predictors of progression and patient outcome. Herein we present a selective overview of the molecular underpinning of urothelial carcinogenesis and progression and discuss the potential for proteins involved in these processes to serve as biomarkers. The discovery of biomarkers has enabled the elucidation of targets for novel therapeutic agents to disrupt the deregulation underlying the development and progression of urothelial carcinogenesis.

Coordinated epigenetic repression of the miR-200 family and miR-205 in invasive bladder cancer

MicroRNAs (miRNA) are small noncoding RNAs commonly deregulated in cancer. The miR-200 family (miR-200a, -200b, -200c, -141 and -429) and miR-205 are frequently silenced in advanced cancer and have been implicated in epithelial to mesenchymal transition (EMT) and tumor invasion by targeting the transcriptional repressors of E-cadherin, ZEB1 and ZEB2. ZEB1 is also known to repress miR-200c-141 transcription in a negative feedback loop, but otherwise little is known about the transcriptional regulation of the miR-200 family and miR-205. Recently, miR-200 silencing was also reported in cancer stem cells, implying that miR-200 deregulation is a key event in multiple levels of tumor biology. However, what prevents miR-200 expression remains largely unanswered. Here we report concerted transcriptional regulation of the miR-200 and miR-205 loci in bladder tumors and bladder cell lines. Using a combination of miRNA expression arrays, qPCR assays and mass spectrometry DNA methylation analyses, we show that the miR-200 and miR-205 loci are specifically silenced and gain promoter hypermethylation and repressive chromatin marks in muscle invasive bladder tumors and undifferentiated bladder cell lines. Moreover, we report that miR-200c expression is significantly correlated with early stage T1 bladder tumor progression, and propose miR-200 and miR-205 silencing and DNA hypermethylation as possible prognostic markers in bladder cancer. In addition, we observe that the mesoderm transcription factor TWIST1 and miR-200 expression are inversely correlated in bladder tumor samples and cell lines. TWIST1 associates directly with the miR-200 and miR-205 promoters, and may act as a repressor of miR-200 and miR-205 expression.

Expression profiling for bladder cancer: strategies to uncover prognostic factors

Despite being a common cancer worldwide, management of transitional cell carcinoma of the bladder currently relies primarily on clinical staging and histopathologic parameters. Assaying alterations in molecular pathways can contribute valuable information that can accurately predict outcome and chemotherapeutic response in individual patients with bladder cancer. Medium- to high-throughput gene-expression profiling technologies are now allowing multiplexed assessment of alterations responsible for the genesis and progression of bladder tumors. These investigations employ global or pathway-based approaches to define molecular signatures that can predict prognosis independent of traditional clinical performance metrics. Prognostic panels generated using these strategies can also elucidate the biology of tumor progression and identify potential therapeutic targets.

Bladder cancer: translating molecular genetic insights into clinical practice

Transitional cell (urothelial) carcinoma of the bladder is the second most common urologic malignancy and is one of the best understood neoplasms, with relatively well-defined pathogenetic pathways, natural history, and tumor biology. Conventional clinical and pathologic parameters are widely used to grade and stage tumors and to predict clinical outcome of transitional cell carcinoma; but the predictive ability of these parameters is limited, and there is a lack of indices that could allow prospective assessment of risk for individual patients. In the last decade, a wide range of candidate biomarkers representing key pathways in carcinogenesis have been reported to be clinically relevant and potentially useful as diagnostic and prognostic molecular markers, and as potential therapeutic targets. The use of molecular markers has facilitated the development of novel and more accurate diagnostic, prognostic, and therapeutic strategies. FGFR3 and TP53 mutations have been recognized as key genetic pathways in the carcinogenesis of transitional cell carcinoma. FGFR3 appears to be the most frequently mutated oncogene in transitional cell carcinoma; its mutation is strongly associated with low tumor grade, early stage, and low recurrence rate, which confer a better overall prognosis. In contrast, TP53 mutations are associated with higher tumor grade, more advanced stage, and more frequent tumor recurrences. These molecular markers offer the potential to characterize individual urothelial neoplasms more completely than is possible by histologic evaluation alone. Areas in which molecular markers may prove valuable include prediction of tumor recurrence, molecular staging of transitional cell carcinoma, detection of lymph node metastasis and circulating cancer cells, identification of therapeutic targets, and prediction of response to therapy. With accumulating molecular knowledge of transitional cell carcinoma, we are closer to the goal of bridging the gap between molecular findings and clinical outcomes. Assessment of key genetic pathways and expression profiles could ultimately establish a set of molecular markers to predict the biological nature of tumors and to establish new standards for molecular tumor grading, classification, and prognostication. The main focus of this review is to discuss clinically relevant biomarkers that might be useful in the management of transitional cell carcinoma and to provide approaches in the analysis of molecular pathways that influence the clinical course of bladder cancer.

Variation of keratin 7 expression and other phenotypic characteristics of independent isolates of cadmium transformed human urothelial cells (UROtsa)

This laboratory has shown that a human urothelial cell line (UROtsa) transformed by cadmium (Cd(2+)) produced subcutaneous tumor heterotransplants that resemble human transitional cell carcinoma (TCC). In the present study, additional Cd(2+) transformed cell lines were isolated to determine if independent exposures of the cell line to Cd(2+) would result in malignantly transformed cell lines possessing similar phenotypic properties. Seven independent isolates were isolated and assessed for their doubling times, morphology, ability to heterotransplant subcutaneously and in the peritoneal cavity of nude mice, and for the expression of keratin 7. The 7 cell lines all displayed an epithelial morphology with no evidence of squamous differentiation. Doubling times were variable among the isolates, being significantly reduced or similar to those of the parental cells. All 7 isolates were able to form subcutaneous tumor heterotransplants with a TCC morphology, and all heterotransplants displayed areas of squamous differentiation of the transitional cells. The degree of squamous differentiation varied among the isolates. In contrast to subcutaneous tumor formation, only 1 isolate of the Cd(2+) transformed cells (UTCd#1) was able to effectively colonize multiple sites within the peritoneal cavity. An analysis of keratin 7 expression showed no correlation with squamous differentiation for the subcutaneous heterotransplants generated from the 7 cell lines. Keratin 7 was expressed in 6 of the 7 cell lines and their subcutaneous tumor heterotransplants. Keratin 7 was not expressed in the cell line that was able to form tumors within the peritoneal cavity. These results show that individual isolates of Cd(2+) transformed cells have both similarities and differences in their phenotype.

Strategies for molecular expression profiling in bladder cancer

Carcinoma of the urinary bladder involves alterations in multiple cellular pathways that dictate the pathology of the disease and clinical outcome of the patient. This includes alterations in regulation of the cell cycle, apoptotic mechanisms, signal transduction and tumor angiogenesis. Interrogation of alterations in multiple molecules associated with these pathways is leading to the development of biomarker panels that are capable of predicting an individual patient's outcome or response to specific treatments. With respect to gene expression profiling, two broad approaches may be identified: a global approach and a pathway-specific approach. The global approach involves a high-throughput effort to profile the entire genome, while the pathway-specific approach quantifies select genes across several pathways. While the former has a high potential for discovery of novel signatures, the latter is important in generating reproducible and concise panels that have the potential for rapid clinical implementation. A combination of both these approaches is needed for the identification and validation of robust marker panels of potential clinical importance in bladder cancer.

Consistent genomic alterations in carcinoma in situ of the urinary bladder confirm the presence of two major pathways in bladder cancer development

Bladder cancer develops through different pathways, provisionally entitled "papillary" and "invasive." Carcinoma in situ (CIS) is thought to be the precursor of invasive bladder cancer. However, little is known about chromosomal alterations of these clinically important lesions, and the relationship between chromosomal alterations and the different pathways. We laser-microdissected 12 CIS and 4 dysplasia samples concomitant to invasive bladder cancer. We determined genome-wide chromosome copy number changes and loss of heterozygosity (LOH) using Mapping 10K SNP microarrays. We further examined 48 high-risk non-muscle-invasive bladder cancers using SNP microarrays to reveal characteristic changes correlated with the CIS-phenotype. DNA copy-number changes were further validated using QPCR in 77 independent tumor samples. CIS was found to be chromosomal unstable in 8 of 12 cases. Characteristic chromosomal changes were copy number gains of chromosomes 5p, 6p22.3, 10p15.1 and losses/LOH of chromosome 5q and 13q13-q14. Tumor samples with these alterations were significantly associated with CIS. Using FGFR3 mutations as markers of the opposing papillary phenotype, we found 5p gains and FGFR3 mutations mutually exclusive. No FGFR3 mutations were found in 23 CIS and dysplasia samples. Based on this, we classified high-risk non-muscle-invasive bladder tumors according to FGFR3 mutations and chromosomal changes into papillary and CIS-type tumors with high correlation to CIS status (p = 0.001). Furthermore, we found significant correlation to the results of molecular classifiers based on gene-expression. We concluded that chromosomal changes may be used to characterize different pathways in bladder cancer development.

Genomic profiling of microRNAs in bladder cancer: miR-129 is associated with poor outcome and promotes cell death in vitro

microRNAs (miRNA) are involved in cancer development and progression, acting as tumor suppressors or oncogenes. Here, we profiled the expression of 290 unique human miRNAs in 11 normal and 106 bladder tumor samples using spotted locked nucleic acid-based oligonucleotide microarrays. We identified several differentially expressed miRNAs between normal urothelium and cancer and between the different disease stages. miR-145 was found to be the most down-regulated in cancer compared with normal, and miR-21 was the most up-regulated in cancer. Furthermore, we identified miRNAs that significantly correlated to the presence of concomitant carcinoma in situ. We identified several miRNAs with prognostic potential for predicting disease progression (e.g., miR-129, miR-133b, and miR-518c*). We localized the expression of miR-145, miR-21, and miR-129 to urothelium by in situ hybridization. We then focused on miR-129 that exerted significant growth inhibition and induced cell death upon transfection with a miR-129 precursor in bladder carcinoma cell lines T24 and SW780 cells. Microarray analysis of T24 cells after transfection showed significant miR-129 target down-regulation (P = 0.0002) and pathway analysis indicated that targets were involved in cell death processes. By analyzing gene expression data from clinical tumor samples, we identified significant expression changes of target mRNA molecules related to the miRNA expression. Using luciferase assays, we documented a direct link between miR-129 and the two putative targets GALNT1 and SOX4. The findings reported here indicate that several miRNAs are differentially regulated in bladder cancer and may form a basis for clinical development of new biomarkers for bladder cancer.

Molecular alterations associated with bladder cancer initiation and progression

Bladder cancer is the fifth most commonly diagnosed non-cutaneous solid malignancy, and the second most commonly diagnosed genitourinary malignancy amongst people living in the United States, where it is estimated that more than 61,000 new cases of bladder cancer will be diagnosed in the year 2008. Approximately 90% of malignant tumors arising in the urinary bladder are of epithelial origin, the majority being transitional cell carcinomas. Early stage bladder tumors have been classified into two groups with distinct behavior and unique molecular profiles: low grade tumors (always papillary and usually superficial), and high-grade tumors (either papillary or non-papillary, and often invasive). Clinically, superficial bladder tumors (stages Ta and Tis) account for 75% to 85% of neoplasms, while the remaining 15% to 25% are invasive (T1, T2-T4) or metastatic lesions at the time of initial presentation. Studies from the author's group and others have revealed that distinct genotypic and phenotypic patterns are associated with early versus late stages of bladder cancer. Most importantly, early superficial diseases appear to segregate into two main pathways. Superficial papillary bladder tumors are characterized by gain-of-function mutations, mainly affecting classical oncogenes such as RAS and FGFR3. Deletions of chromosome 9, mainly allelic losses on the long arm (9q) are also frequent events in these tumors. Such genetic alterations are observed in most if not all superficial papillary non-invasive tumors (Ta), but only in a small subset of invasive bladder neoplasms. Flat carcinoma in situ (Tis) and invasive tumors are characterized by loss-of-function mutations, affecting the prototype tumor suppressor genes, including p53, RB and PTEN. These alterations are absent or very rare in the Ta tumors analyzed, but have been frequently identified in invasive bladder carcinomas. Based on these data, a novel model for bladder tumor progression has been proposed in which two separate genetic pathways characterize the evolution of superficial bladder neoplasms. Numerous individual molecular markers have been identified in the tissue specimens that correlate to some extent with tumor stage, and possibly with prognosis in bladder cancer. However, these molecular prognosticators do not play a role in the clinical routine management of patients with bladder tumors, mainly due to lack of large prospective validation studies. Thus, the need for development of specific tissue and serum tumor markers for prognostic stratification remains. The advent of high-throughput microarrays technologies allows comprehensive discovery of targets relevant in bladder cancer progression, which could be translated into new approaches for drug and biomarker development. Further investigation is warranted to define novel biomarkers specific for bladder cancer patients based on the molecular alterations of tumor progression, and multiplexed strategies for clinical management.

Relationship of SNCG, S100A4, S100A9 and LCN2 gene expression and DNA methylation in bladder cancer

Microarray analysis of paired cultures of normal and cancerous urothelial cells revealed differences in cytokeratin and adhesion gene expression. Normal cells expressed autocrine growth factor genes more strongly whereas carcinoma cells were distinguished by concomitant expression of urothelial and epidermal differentiation markers. Expression of SNCG, S100A9 and LCN2 was also enhanced. In other cancers, overexpression of SNCG, LCN2 and S100A4 has been ascribed to DNA hypomethylation. We therefore investigated expression and methylation of SNCG, S100A4, S100A9 and LCN2 in urothelial cancer cell lines and tissues. SNCG and S100A4 were overexpressed in some cancer tissues and cell lines, but downregulated in others, whereas LCN2 and S100A9 were upregulated in few cancer cell lines, but regularly in tissues. Normal and cancerous urothelial cells expressing SNCG lacked promoter methylation. SNCG downregulation was associated with hypermethylation and could be reversed by the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine. S100A4 methylation at regulatory intronic sites and in the promoter region was lowest in leukocytes and fibroblasts, and denser in urothelial cells. Gene expression responded to 5-aza-2'-deoxycytidine. LCN2 promoter methylation was variable and even less consistently related to expression. The S100A9 promoter was partially methylated in nonexpressing cells, but 5-aza-2'-deoxycytidine had no effect. Our data indicate that SNCG methylation is cell type-specific and the gene is hypermethylated in some urothelial cancers. S100A4, S100A9 and LCN2 are genes with moderate CpG-density that show a less stringent relationship between DNA methylation and gene expression. Therefore, changes in methylation of these genes in cancer should be interpreted cautiously.

A microRNA expression ratio defining the invasive phenotype in bladder tumors

OBJECTIVE

The goal of this study was to identify a microRNA (miRNA) signature in bladder cancer capable of differentiating superficial from invasive disease.

METHODS

Expression profiling of 343 miRNAs was performed in a microarray format using noninvasive and invasive bladder carcinoma cell lines with differential expression confirmed using a single molecule detection platform assay. miR-21 and miR-205 expression levels were determined in 53 bladder tumors (28 superficial and 25 invasive). Sensitivity, specificity, and a ROC curve were calculated to determine the discriminatory power of the miRNA ratio to predict invasion. Knockdown and forced expression of miRNAs was performed to evaluate their role in invasion.

RESULTS

Expression profiling of 343 miRNAs, using noninvasive and invasive bladder cell lines, revealed significant differential expression of 9 miRNAs. Cell lines characterized as invasive showed a miR-21:miR-205 ratio at least 10-fold higher than the quantitative ratio obtained from non-invasive cell lines. The same expression ratio was determined in 53 bladder tumors. From these results, we recorded a sensitivity and specificity of 100% and 78%, respectively, using a cutoff of 1.79 to predict an invasive lesion. The area under the receiver operator characteristic curve was 0.89. Using in vitro invasion assays, we have demonstrated a role for miR-21 in establishing the invasive phenotype of bladder carcinoma cells.

CONCLUSION

In this study, we identified a miR-21:miR-205 expression ratio that has the ability to distinguish between invasive and noninvasive bladder tumors with high sensitivity and specificity, with the potential to identify superficial lesions at high risk to progress.

Increased cell motility and invasion upon knockdown of lipolysis stimulated lipoprotein receptor (LSR) in SW780 bladder cancer cells

BACKGROUND

Mechanisms underlying the malignant development in bladder cancer are still not well understood. Lipolysis stimulated lipoprotein receptor (LSR) has previously been found to be upregulated by P53. Furthermore, we have previously found LSR to be differentially expressed in bladder cancer. Here we investigated the role of LSR in bladder cancer.

METHODS

A time course siRNA knock down experiment was performed to investigate the functional role of LSR in SW780 bladder cancer cells. Since LSR was previously shown to be regulated by P53, siRNA against TP53 was included in the experimental setup. We used Affymetrix GeneChips for measuring gene expression changes and we used Ingenuity Pathway Analysis to investigate the relationship among differentially expressed genes upon siRNA knockdown.

RESULTS

By Ingenuity Pathway analysis of the microarray data from the different timepoints we identified six gene networks containing genes mainly related to the functional categories "cancer", "cell death", and "cellular movement". We determined that genes annotated to the functional category "cellular movement" including "invasion" and "cell motility" were highly significantly overrepresented. A matrigel assay showed that 24 h after transfection the invasion capacity was significantly increased 3-fold (p < 0.02) in LSR-siRNA transfected cells, and 2.7-fold (p < 0.02) in TP53-siRNA transfected cells compared to controls. After 48 h the motility capacity was significantly increased 3.5-fold (p < 0.004) in LSR-siRNA transfected cells, and 4.7-fold (p < 0.002) in TP53-siRNA transfected cells compared to controls.

CONCLUSION

We conclude that LSR may impair bladder cancer cells from gaining invasive properties.

Bioinformatic identification of FGF, p38-MAPK, and calcium signalling pathways associated with carcinoma in situ in the urinary bladder

Background

Carcinoma in situ (CIS) is believed to be a precursor of invasive bladder cancer. Identification of CIS is a valuable prognostic factor since radical treatment strategies can be offered these patients before the disease becomes invasive.

Methods

We developed a pathway based classifier approach to predict presence or absence of CIS in patients suffering from non muscle invasive bladder cancer. From Ingenuity Pathway Analysis we considered four canonical signalling pathways (p38 MAPK, FGF, Calcium, and cAMP pathways) with most coherent expression of transcription factors (TFs) across samples in a set of twenty-eight non muscle invasive bladder carcinomas. These pathways contained twelve TFs in total. We used the expression of the TFs to predict presence or absence of CIS in a Leave-One-Out Cross Validation classification.

Results

We showed that TF expression levels in three pathways (FGF, p38 MAPK, and calcium signalling) or the expression of the twelve TFs together could be used to predict presence or absence of concomitant CIS. A cluster analysis based on expression of the twelve TFs separated the samples in two main clusters: one branch contained 11 of the 15 patients without concomitant CIS and with the majority of the genes being down regulated; the other branch contained 10 of 13 patients with concomitant CIS, and here genes were mostly up regulated. The expression in the CIS group was comparable to the expression of twenty-three patients suffering from muscle-invasive bladder carcinoma. Finally, we validated our results in an independent test set and found that prediction of CIS status was possible using TF expression of the p38 MAPK pathway.

Conclusion

We conclude that it is possible to use pathway analysis for molecular classification of bladder tumors.

p53 and retinoblastoma pathways in bladder cancer

A majority of the aggressive, invasive bladder carcinomas have alterations in the p53 and retinoblastoma genes and pathways. Examination of the alterations in the molecules in these pathways that regulate the cell cycle and their effects on the prognosis of bladder cancer are areas of active research. While defects in the p53-Mdm2-p14 axis have been implicated in urothelial cancer, perturbations in the cyclin-dependent kinases and their inhibitors have also been extensively studied in this context. Genetic alterations of the retinoblastoma gene and aberrant post-translational modifications of its protein have also been incriminated in invasive bladder cancer. This article reviews the individual prognostic roles of alterations in these molecules in the context of bladder cancer. Additionally, we review findings from recent studies that are attempting to analyze these markers in combination in an effort to construct molecular panels that can serve as more robust outcome predictors. More importantly, alterations in these molecules are now becoming enticing targets for novel therapeutics. We also review some of these agents that can restore the tumor cells' altered homeostatic mechanisms, thereby having potential in transitional cell carcinoma therapy. Future management of bladder cancer will employ validated marker panels for outcome prediction, and novel genetic and pharmacologic agents that will be able to target molecular alterations in individual tumors based on their respective profiles.

Molecular alterations associated with bladder cancer progression

Clinically, superficial tumors (stages Ta, Tis, and T1) account for 75% to 85% of bladder neoplasms, while the remaining 15% to 25% are invasive (T2, T3, T4) or metastatic lesions at the time of initial presentation. More than 70% of patients with superficial tumors will have one or more recurrences after initial treatment, and about one third of those patients will progress and eventually die of the disease. New methods are needed to identify and monitor patients presenting with "high-risk" superficial tumors likely to develop into invasive carcinoma. Once invasive into muscle, the natural history is quite variable but highly lethal. Despite aggressive surgical resection, radiotherapy, and/or chemotherapy, the overall cure rate remains in the range of 20% to 50%. New biological determinants are needed both for proper selection of therapy and monitoring. In this review, we describe and update molecular alterations reportedly associated with bladder tumorigenesis and cancer progression. We also review novel genes and "signaling networks" identified by the use of high-throughput technologies. The concept of alterations affecting "genetic pathways" is becoming more than just a molecular biology exercise. The challenge is to evaluate such targets for therapeutic development, as well as to translate progression and outcome biomarkers into improved clinical management. Integration of data generated from in-depth clinical evaluation, histologic tumor characteristics, and validated biomarkers could provide highly accurate, predictive tools for management of the bladder cancer patient.

Lens epithelium-derived growth factor is an Hsp70-2 regulated guardian of lysosomal stability in human cancer

Heat shock protein 70-2 (Hsp70-2) is a chaperone protein essential for the growth of spermatocytes and cancer cells. Here, we show that Hsp70-2 depletion triggers lysosomal membrane permeabilization and cathepsin-dependent cell death and identify lens epithelium-derived growth factor (LEDGF) as an Hsp70-2-regulated guardian of lysosomal stability in human cancer. Knockdown of LEDGF in cancer cells induces destabilization of lysosomal membranes followed by caspase-independent and Bcl-2-resistant cell death. Accordingly, ectopic LEDGF stabilizes lysosomes and protects cancer cells against cytotoxicity induced by anticancer agents that trigger the lysosomal cell death pathway. Remarkably, ectopic LEDGF also increases the tumorigenic potential of human cancer cells in immunodeficient mice, and LEDGF expression is increased in human breast and bladder carcinomas correlating with that of Hsp70-2 in invasive bladder cancer. Taken together, these data reveal LEDGF as an oncogenic protein that controls a caspase-independent lysosomal cell death pathway.

Molecular biology of bladder cancer: prognostic and clinical implications

The role of various molecular determinants involved in the genesis, progression, and outcome of bladder cancer has been the focus of investigations for the past 2 decades. Increasingly, the analysis of the interplay between these molecular factors is taking center stage. We review herein the studies examining the effects of deregulation of the various molecules implicated in the cell cycle, apoptosis, and angiogenesis pathways and analyze the central role of p53 in regulating these pathways. Technological advancements enable detection and quantification of gene transcripts and protein products, helping us move toward achieving the goal of establishing diagnostic, prognostic, and therapeutic marker panels. Recent studies have therefore focused on multiple-marker analyses to generate informative panels that can have greater clinical value for bladder cancer management. The use of molecular marker panels can provide a more objective alternative to clinical parameters for diagnosis and treatment decisions. Clinical trials aimed at treating urothelial carcinoma based on a patient's molecular profile can be predicted to empower clinicians to personalize patient management through increased therapeutic efficacy.

Recent developments in molecular profiling of bladder cancer

PURPOSE OF REVIEW

Profiling bladder tumors using high-density microarrays has recently become possible. We review recent reports on the use of profiling for the prediction of various clinical courses in bladder cancer. We also stress the methods and materials needed to translate such molecular profiles into clinically useful tests.

RECENT FINDINGS

Using gene expression microarrays, it has been possible to identify signatures that predict various properties of bladder cancer such as stage, grade, progression, and likelihood of metastases. Using arrays for genomic instability, similar properties have been examined, but the effectiveness seems to be less than that of gene expression. Some of genes identified also work as predictors using immunohistochemistry.

SUMMARY

The signatures or molecular profiles for some of these arrays are now being tested in multicenter studies with the purpose of introducing these into the clinic, for planning of follow-up and treatment selection.

SOX4 expression in bladder carcinoma: clinical aspects and in vitro functional characterization

The human transcription factor SOX4 was 5-fold up-regulated in bladder tumors compared with normal tissue based on whole-genome expression profiling of 166 clinical bladder tumor samples and 27 normal urothelium samples. Using a SOX4-specific antibody, we found that the cancer cells expressed the SOX4 protein and, thus, did an evaluation of SOX4 protein expression in 2,360 bladder tumors using a tissue microarray with clinical annotation. We found a correlation (P < 0.05) between strong SOX4 expression and increased patient survival. When overexpressed in the bladder cell line HU609, SOX4 strongly impaired cell viability and promoted apoptosis. To characterize downstream target genes and SOX4-induced pathways, we used a time-course global expression study of the overexpressed SOX4. Analysis of the microarray data showed 130 novel SOX4-related genes, some involved in signal transduction (MAP2K5), angiogenesis (NRP2), and cell cycle arrest (PIK3R3) and others with unknown functions (CGI-62). Among the genes regulated by SOX4, 25 contained at least one SOX4-binding motif in the promoter sequence, suggesting a direct binding of SOX4. The gene set identified in vitro was analyzed in the clinical bladder material and a small subset of the genes showed a high correlation to SOX4 expression. The present data suggest a role of SOX4 in the bladder cancer disease.

Cyclin D3 expression in primary Ta/T1 bladder cancer

Cyclin D3 deregulation has recently been reported in bladder cancer but its prognostic significance remains uncertain. A cohort of 159 patients with stage Ta or T1 primary bladder tumours was investigated to determine the significance of cyclin D3 expression in association with other G1-S phase regulators of the cell cycle (p53, p21Waf1, p27kip1, cyclin D1), including tumour proliferation (ki67-MIB1); its association with conventional clinicopathological parameters; and the relationship between cyclin D3 and loss of heterozygosity (LOH) at the 9p21 (p16INK4a locus) chromosome region. The end point of the study was progression-free survival. Cyclin D3, other G1-S phase regulators, and tumour proliferation were investigated by immunohistochemistry and measured by the grid-counting method. To validate the immunohistochemical expression, cyclin D3 was additionally assessed by western blotting in selected cases. LOH at the 9p21 chromosome region (marker D9S171) was assessed in 125 cases using an AB Prism 310 genetic analyser and a set of microsatellite fluorescence-labelled primers. Cyclin D3 overexpression was related to larger tumour size (>5 cm; p < 0.0001) and high tumour proliferation (>10%; p = 0.025). Mean cyclin D3 expression increased with 2004 WHO grading categories in stage Ta (p = 0.035, ANOVA) and stage T1 (p = 0.047, t test) tumours. Cyclin D3 was not related to other clinicopathological parameters, G1-S phase modulators, or 9p21 LOH. Cox's multivariate analysis selected cyclin D3 as an independent predictor of progression-free survival (p = 0.0012, relative risk (RR) = 5.2366) together with tumour size (p = 0.0115, RR = 4.4442) and cyclin D1 (p = 0.0065, RR = 3.3023). Cyclin D3 expression had the highest risk ratio. Our results suggest that expression of cyclin D3 is relevant to the progression-free survival of patients with Ta/T1 bladder carcinomas.