DNA ploidy as a prognostic factor in muscle invasive transitional cell carcinoma of the bladder

Impairment of α-tubulin and F-actin interactions of GJB3 induces aneuploidy in urothelial cells and promotes bladder cancer cell invasion

BACKGROUND

We have previously identified an unsuspected role for GJB3 showing that the deficiency of this connexin protein induces aneuploidy in human and murine cells and accelerates cell transformation as well as tumor formation in xenograft models. The molecular mechanisms by which loss of GJB3 leads to aneuploidy and cancer initiation and progression remain unsolved.

METHODS

GJB3 expression levels were determined by RT-qPCR and Western blot. The consequences of GJB3 knockdown on genome instability were assessed by metaphase chromosome counting, multinucleation of cells, by micronuclei formation and by the determination of spindle orientation. Interactions of GJB3 with α-tubulin and F-actin was analyzed by immunoprecipitation and immunocytochemistry. Consequences of GJB3 deficiency on microtubule and actin dynamics were measured by live cell imaging and fluorescence recovery after photobleaching experiments, respectively. Immunohistochemistry was used to determine GJB3 levels on human and murine bladder cancer tissue sections. Bladder cancer in mice was chemically induced by BBN-treatment.

RESULTS

We find that GJB3 is highly expressed in the ureter and bladder epithelium, but it is downregulated in invasive bladder cancer cell lines and during tumor progression in both human and mouse bladder cancer. Downregulation of GJB3 expression leads to aneuploidy and genomic instability in karyotypically stable urothelial cells and experimental modulation of GJB3 levels alters the migration and invasive capacity of bladder cancer cell lines. Importantly, GJB3 interacts both with α-tubulin and F-actin. The impairment of these interactions alters the dynamics of these cytoskeletal components and leads to defective spindle orientation.

CONCLUSION

We conclude that deregulated microtubule and actin dynamics have an impact on proper chromosome separation and tumor cell invasion and migration. Consequently, these observations indicate a possible role for GJB3 in the onset and spreading of bladder cancer and demonstrate a molecular link between enhanced aneuploidy and invasive capacity cancer cells during tumor cell dissemination.

Accurate Characterization of Bladder Cancer Cells with Intraoperative Flow Cytometry

Simple Summary

Bladder cancer is a malignancy that predominantly affects male patients. Surgical treatment is the first option for clinical management and cancer cell characterization is critical for tumor margin detection and complete tumor removal. We developed a specialized intraoperative flow cytometry (iFC) methodology for bladder cancer cell detection. Our study, including 52 individuals, reveals that iFC is highly specific, sensitive and accurate in detecting cancer cells, based on the quantification of cell proliferation and the presence of tumor aneuploidy. The results of this study advocate further research on the utility of iFC as a next-generation malignancy evaluation technique during transurethral resections.

Abstract

Bladder cancer represents a major health issue. Transurethral resection is the first line treatment and an accurate assessment of tumor margins might warrant complete tumor removal. Genomic instability and proliferative potential are common hallmarks of cancer cells. We have previously demonstrated the utility of intraoperative flow cytometry (iFC), a next-generation margin evaluation methodology for assessment of DNA content, in the detection of several types of malignancy. In the current study we investigated the possible value of iFC in the characterization of bladder cancer during surgery. Samples from a population of 52 people with urothelial cancer were included in the study. The total time for iFC evaluation is 3–5 min per sample and included a two-step analysis, including DNA-index and Tumor-index calculation. First, DNA-index calculation revealed 24 hyperploid and one hypoploid tumor. Second, cell cycle analysis and Tumor-index calculation revealed that tumor samples are distinguished from normal cells based on their significantly higher proliferative potential. The standard for iFC evaluation was pathology assessment and revealed that our protocol exhibits an accuracy of 98% in defining the presence of cancer cells in a given sample. Our results support the further assessment of iFC value towards its use as a novel malignancy evaluation tool in transurethral resections.

S-phase - an independent prognostic marker in upper tract urothelial carcinoma

OBJECTIVES

To evaluate S-phase fraction as a predictor of invasiveness and cancer-specific survival in upper tract urothelial carcinoma (UTUC).

PATIENTS AND METHODS

One hundred and fifteen patients having undergone radical nephroureterectomy were analysed with histology in radical nephroureterectomy specimens as reference test and S-phase fraction as index test. Ploidy and S-phase were determined using flow cytometry. Differences in S-phase fraction were calculated between stages, grades (WHO 1999 and 2004 classifications), ploidy and patients that died of UTUC and those who did not. Five- and 10-year-cancer-specific survivals were calculated. Areas under the ROC curve (AUCs) of S-phase fraction in relation to tumour stage and to death from UTUC were measured. Multiple Cox regression was performed.

RESULTS

Independent prognostic markers of death from UTUC were S-phase fraction and stage. Correlation between S-phase fraction and risk of dying from UTUC was strong, with a 17% greater risk of death from UTUC with every 1% increase in S-phase fraction, hazard ratio = 1.17, 95% CI = 1.10-1.25, p < 0.001, Spearman's rho ρ = 0.65. AUCs for S-phase fraction as predictors of stage and death from UTUC were 0.8 (95% CI = 0.705-0.894) and 0.77 (95% CI = 0.67-0.87), respectively. Cancer-specific survival was statistically significantly different between stages, ploidy and WHO 1999 grades, but not between WHO 2004 grades. This was also reflected in S-phase fraction, which differed in LG-G1 compared with LG-G2 and in HG-G2 compared with HG-G3.

CONCLUSION

S-phase fraction was a good test for predicting both invasiveness and cancer-specific survival. Using both WHO 1999 and 2004 classifications, rather than one system alone, had a higher predictive value of cancer-specific survival.

The New Age of -omics in Urothelial Cancer - Re-wording Its Diagnosis and Treatment

Unmet needs in urothelial cancer management represent an important challenge in our effort to improve long-term overall and disease-free survival rates with no significant compromise in quality of life. Radical cystectomy with pelvic lymph node dissection is the standard for the management of muscle-invasive, non-metastatic cancers. In spite of a 90% local disease control, up to 50% of patients ultimately die of distant metastasis. Bladder preservation using chemo-radiation is an acceptable alternative, but optimal patient selection remains elusive. Recent research is focused on the employment of tailored-made strategies in urothelial cancer exploiting the potential of theranostics in patient selection for specific therapies. Herein, we review the current knowledge on molecular theranostics in urothelial cancer and we suggest that this is the time to move toward imaging theranostics, if tailored-made disease management and patient stratification is envisaged.

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Urothelial cancer management represents an important challenge.

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Optimum patient stratification and tailored-made theranostics remain elusive.

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Imaging theranostics is envisaged as a cancer roadmap.

Revisiting tumour aneuploidy - the place of ploidy assessment in the molecular era

Chromosome instability (CIN) is gaining increasing interest as a central process in cancer. CIN, either past or present, is indicated whenever tumour cells harbour an abnormal quantity of DNA, termed 'aneuploidy'. At present, the most widely used approach to detecting aneuploidy is DNA cytometry - a well-known research assay that involves staining of DNA in the nuclei of cells from a tissue sample, followed by analysis using quantitative flow cytometry or microscopic imaging. Aneuploidy in cancer tissue has been implicated as a predictor of a poor prognosis. In this Review, we have explored this hypothesis by surveying the current landscape of peer-reviewed research in which DNA cytometry has been applied in studies with disease-appropriate clinical follow up. This area of research is broad, however, and we restricted our survey to results published since 2000 relating to seven common epithelial cancers (those of the breast; endometrium, ovary, and uterine cervix; oesophagus; colon and rectum; lung; prostate; and bladder). We placed particular emphasis on results from multivariate analyses to pinpoint situations in which the prognostic value of aneuploidy as a biomarker is strong compared with that of existing indicators, such as clinical stage, histological grade, and specific molecular markers. We summarize the implications of our findings for the prognostic use of ploidy analysis in the clinic and for the theoretical understanding of the role of CIN in carcinogenesis.

PTEN deletions are related to disease progression and unfavourable prognosis in early bladder cancer

AIMS

This study aimed to determine the prevalence and clinical significance of deletions of the tumour suppressor gene PTEN in bladder cancer.

METHODS AND RESULTS

A tissue microarray with 686 bladder cancers was analysed for PTEN deletions by fluorescence in-situ hybridization. PTEN mutations were analysed in nine tumours with heterozygous PTEN deletion. Heterozygous PTEN deletions were present in 16.5% of tumours and were associated with grade (P = 0.0024) and p53 status (P = 0.0141), but not linked to stage (P = 0.0965). PTEN deletions were seen in 5.8% of pTaG1, 10.9% of pTaG2, 29.0% of pTaG3, 16.7% of pT1G2, 22.2% of pT1G3, 17.7% of pT2-4G2 and 20.9% of pT2-4G3 tumours (P = 0.0235). PTEN deletions were associated significantly with recurrences in pTa tumours (P = 0.0173), progression in pT1 tumours (P = 0.0016), but not with overall or cancer-specific survival in pT2 tumours. Multivariate analyses including grade and PTEN deletions revealed that PTEN deletions but not grade were associated independently with recurrence in pTa tumours (P = 0.0377) and progression in pT1 tumours (P = 0.0030). No inactivating PTEN mutations were found.

CONCLUSIONS

PTEN is linked to aggressive tumour phenotype and to unfavourable outcome in early bladder cancer. Heterozygous PTEN loss, i.e. reduced PTEN gene dosage, might be sufficient to cause aggressive tumour behaviour in bladder cancer cells.

Whole-pelvis or bladder-only chemoradiation for lymph node-negative invasive bladder cancer: single-institution experience

PURPOSE

Whole-pelvis (WP) concurrent chemoradiation (CCRT) is the standard bladder preserving option for patients with invasive bladder cancer. The standard practice is to treat elective pelvic lymph nodes, so our aim was to evaluate whether bladder-only (BO) CCRT leads to results similar to those obtained by standard WP-CCRT.

METHODS AND MATERIALS

Patient eligibility included histopathologically proven muscle-invasive bladder cancer, lymph nodes negative (T2-T4, N-) by radiology, and maximal transurethral resection of bladder tumor with normal hematologic, renal, and liver functions. Between March 2005 and May 2006, 230 patients were accrued. Patients were randomly assigned to WP-CCRT (120 patients) and BO-CCRT (110 patients). Data regarding the toxicity profile, compliance, initial complete response rates at 3 months, and occurrence of locoregional or distant failure were recorded.

RESULTS

With a median follow-up time of 5 years (range, 3-6), WP-CCRT was associated with a 5-year disease-free survival of 47.1% compared with 46.9% in patients treated with BO-CCRT (p = 0.5). The bladder preservation rates were 58.9% and 57.1% in WP-CCRT and BO-CCRT, respectively (p = 0.8), and the 5-year overall survival rates were 52.9% for WP-CCRT and 51% for BO-CCRT (p = 0.8).

CONCLUSION

BO-CCRT showed similar rates of bladder preservation, disease-free survival, and overall survival rates as those of WP-CCRT. Smaller field sizes including bladder with 2-cm margins can be used as bladder preservation protocol for patients with muscle-invasive lymph node-negative bladder cancer to minimize the side effects of CCRT.

Exposure to the tobacco smoke constituent 4-aminobiphenyl induces chromosomal instability in human cancer cells

The relationships between environmental factors and the genetic abnormalities that drive carcinogenesis are supported by experimental and epidemiologic evidence but their molecular basis has not been fully elucidated. At the genomic level, most human cancers display either chromosomal (CIN) or microsatellite (MIN) instability. The molecular mechanisms through which normal cells acquire these forms of instability are largely unknown. The arylamine 4-aminobiphenyl (4-ABP) is a tobacco smoke constituent, an environmental contaminant, and a well-established carcinogen in humans. Among others, bladder, lung, colon, and breast cancers have been associated with 4-ABP. We have investigated the effects of 4-ABP and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) on genetically stable colorectal (HCT116) and bladder (RT112) cancer cells. Cells were treated with carcinogens to generate resistant clones that were then subjected to genetic analysis to assess whether they displayed either CIN or MIN. We found that 50% to 60% of cells treated with 4-ABP developed CIN but none developed MIN as confirmed by their ability to gain and lose chromosomes. In contrast, all MNNG-treated clones (12/12) developed MIN but none developed CIN as shown by the microsatellite assay. The mismatch repair protein expression analysis suggests that the acquired mechanism of MIN resistance in the HCT116 MNNG-treated cells is associated with the reduction or the complete loss of MLH1 expression. By providing a mechanistic link between exposure to a tobacco constituent and the development of CIN, our results contribute to a better understanding of the origins of genetic instability, one of the remaining unsolved problems in cancer research.

Fluorescence in-situ hybridisation on biopsies from clam ileocystoplasties and on a clam cancer

The incidence of carcinoma following an enterocystoplasty increases with time and is a major concern after such procedures. The aim of this study was to investigate genetic instability (in the form of numerical chromosomal aberrations) at the enterovesical anastomosis in patients who had undergone a clam ileocystoplasty using fluorescent in-situ hybridisation (FISH). Fluorescent in-situ hybridisation was performed on touch preparation samples prepared from fresh endoscopic biopsies obtained from the enterovesical anastomosis and native bladder remnant (control specimens) of 15 patients who had undergone a clam ileocystoplasty. Fluorescent in-situ hybridisation was also performed on one squamous cell cancer specimen. Significant aneusomic changes were found at the enterovesical anastomosis in all 15 patients. Alterations in chromosome 18 copy number were the most frequent abnormal finding (trisomy 18, n=8; monosomy 18, n=7). Nine patients were monosomic for chromosome 9. Isolated monosomy 8 and trisomy 8 were each found in one patient. The control specimens were all normal. An unusually high incidence of polysomic cells was found in the clam tumour specimen, reflecting the aggressive nature of this cancer. Chromosomal numerical abnormalities occur at the enterovesical anastomosis following a clam ileocystoplasty and chromosome 18 appears to be a particularly good marker of genetic instability. The results of this study indicate that morphologically normal tissue obtained from the enterovesical anastomosis displays evidence of chromosomal instability that may predispose to tumour formation. However, further prospective, blinded, longitudinal studies are required to establish whether predetermined FISH signal patterns in enterocystoplasty cells in urine or obtained by biopsy predict the presence or absence of tumour.

Deoxyribonucleic acid content as an indicator of progression of squamous cell carcinogenesis in the esophagus: Comparative analysis on imprint-cytospin and tissue section preparation

BACKGROUND

The purpose of this study was to explore the potential use of image analysis on tissue sections preparation as a predictive marker of early malignant changes during squamous cell (SC) carcinogenesis in the esophagus. Results of DNA ploidy quantification on formalin-fixed, paraffin-embedded tissue using two different techniques were compared: imprint-cytospin and 6 microm thick tissue sections preparation.

METHODS

This retrospective study included 26 surgical specimens of squamous cell carcinoma (SCC) from patients who underwent surgery alone at the Department of Surgery in CHUV Hospital in Lausanne between January 1993 and December 2000. We analyzed 53 samples of healthy tissue, 43 tumors and 7 lymph node metastases.

RESULTS

Diploid DNA histogram patterns were observed in all histologically healthy tissues, either distant or proximal to the lesion. Aneuploidy was observed in 34 (79%) of 43 carcinomas, namely 24 (75%) of 32 early squamous cell carcinomas and 10 (91%) of 11 advanced carcinomas. DNA content was similar in the different tumor stages, whether patients presented with single or multiple synchronous tumors. All lymph node metastases had similar DNA content as their primary tumor.

CONCLUSIONS

Early malignant changes in the esophagus are associated with alteration in DNA content, and aneuploidy tends to correlate with progression of invasive SCC. A very good correlation between imprint-cytospin and tissue section analysis was observed. Although each method used here showed advantages and disadvantages; tissue sections preparation provided useful information on aberrant cell-cycle regulation and helped select the optimal treatment for the individual patient along with consideration of other clinical parameters.