Tatsuaki Yoneda

Epigenetic inactivation of wnt inhibitory factor-1 plays an important role in bladder cancer through aberrant canonical Wnt/β-catenin signaling pathway

Purpose: Aberrant activation of the Wingless-type (Wnt) pathway plays a significant role in the pathogenesis of several human cancers. Wnt inhibitory factor-1 (Wif-1) was identified as one of the secreted antagonists that can bind Wnt protein. We hypothesize that Wif-1 plays an important role in bladder cancer pathogenesis. Experimental Design: To test this hypothesis, epigenetic and genetic pathways involved in the Wif-1 gene modulation and expression of Wnt/β-catenin-related genes were analyzed in 4 bladder tumor cell lines and 54 bladder tumor and matched normal bladder mucosa. Results: Wif-1 mRNA expression was significantly enhanced after 5-aza-2′-deoxycytidine treatment in bladder tumor cell lines. Wif-1 promoter methylation level was significantly higher and Wif-1 mRNA expression was significantly lower in bladder tumor samples than in bladder mucosa samples. In the total bladder tumor and bladder mucosa samples, an inverse correlation was found between promoter methylation and Wif-1 mRNA transcript levels. However, loss-of-heterozygosity at chromosome 12q14.3 close to the Wif-1 gene loci was a rare event (3.7%). Nuclear accumulation of β-catenin was significantly more frequent in bladder tumor than in bladder mucosa and inversely correlated with Wif-1 expression. In addition, known targets of the canonical Wnt/β-catenin signaling pathway, such as c-myc and cyclin D1, were up-regulated in bladder tumor compared with bladder mucosa, and this up-regulation was associated with reduced Wif-1 expression at both mRNA and protein levels. Furthermore, transfection of Wif-1 small interfering RNA into bladder tumor cells expressing Wif-1 mRNA transcripts had increased levels of c-myc and cyclin D1 and accelerated cell growth. Conclusion: This is the first report showing that CpG hypermethylation of the Wif-1 promoter is a frequent event in bladder tumor and may contribute to pathogenesis of bladder cancer through aberrant canonical Wnt/β-catenin signaling pathway. The present study elucidates novel pathways that are involved in the pathogenesis of bladder cancer.

Bcl-2 Expression as a Predictive Marker of Hormone-Refractory Prostate Cancer Treated with Taxane-Based Chemotherapy

Purpose: Bcl-2 inhibits apoptosis, and its overexpression is associated with hormone refractory prostate cancer (HRPC). Bak and Bax are in the Bcl-2 family and counteract the antiapoptotic function of Bcl-2. Taxane-induced (paclitaxel and its analogue docetaxel) phosphorylation of Bcl-2 abolishes the potential antiapoptotic effect of Bcl-2. We hypothesized that (a) survival benefit in HRPC patients treated with taxanes is determined by the presence of Bcl-2 protein and (b) altered expression of Bak and Bax protein caused by genetic mutation is associated with biological aggressiveness of prostate cancer. Experimental Design: Forty localized prostate cancer and 30 HRPC cases were used in this study. Surgical specimens of localized prostate cancer and biopsy specimens of HRPC were used for immunostaining of Bcl-2, Bak, and Bax as well as DNA extraction. Mutations in the Bak and Bax genes were screened by single-strand conformational polymorphism, and confirmed by direct DNA sequencing. Results: Bcl-2–positive HRPC showed longer cause-specific survival in comparison with the counterparts. Multivariate analysis revealed that the level of Bcl-2 expression before treatment with taxane-based chemotherapy was an independent predictor for cause-specific survival (P < 0.01) and baseline prostate-specific antigen level was an independent predictor for progression-free survival (P < 0.01). Bax gene mutation was found in only one HRPC specimen. Conclusions: Bcl-2 expression in addition to prostate-specific antigen measurement before treatment could identify HRPC patients who may benefit from taxane-based chemotherapy. Mutation of the Bak and Bax genes is a rare event in prostate cancer.

Initial evaluation of prostate cancer with real-time elastography based on step-section pathologic analysis after radical prostatectomy: A preliminary study

Objective:  To determine whether real‐time elastography can be used to detect prostate cancer as a relatively non‐invasive modality based on the tissue strain value.

Clinical significance of mdm2 and p53 expression in bladder cancer. A comparison with cell proliferation and apoptosis.

Background: Clinical significance of immunohistochemically detectable level of p53 protein has been reported, but with some limitation as a prognosticator of bladder cancer patients. Whether or not simultaneous evaluation of mdm2 and p53 expression in bladder cancer exceed the prognostic significance of conventional histological findings, cell proliferation markers and apoptotic parameters remains unclear. Materials and Methods: The paraffin-embedded materials taken from 84 patients with transitional cell carcinoma of the bladder who were treated with total cystectomy were used in this study. Immunostainings of p53 protein, mdm2 protein and Ki67 antigen were performed using monoclonal antibodies (clone DO7, clone 1B10 and clone MIB1, respectively). In addition, the apoptotic cells were determined using a terminal deoxynucleotidyl transferase (TdT) mediated dUTP biotin nick end labeling (TUNEL) technique. The results were quantitatively evaluated using a CAS 200 Image Analyzer (Cell Analysis System, Elmhurst, Ill., USA) and were compared with histological findings and clinical course. Results: The mean values of mdm2 expression, p53 immunoreactivity, Ki67 expression and apoptotic index were 19.2, 20.5, 22.4 and 0.96%, respectively. Histological grade and pT category were significantly positively correlated with 53 immunoractivity (p < 0.05 and p < 0.05, respectively), Ki67 expression (p < 0.005 and p < 0.0001, respectively) and apoptotic index (p < 0.01 and p < 0.0001, respectively), while both were not correlated with mdm2 expression. Using univariate analysis, the prognostic relevance for both survival and disease progression was noted in histological grade, pT category, p53 expression, Ki67 index and apoptotic index, whereas it was not in mdm2 expression. However, when analyzing the simultaneous evaluation of mdm2 and p53 expression (mdm2-p53 category), the relationship of the mdm2-p53 category with Ki67 expression and apoptotic index showed a statistical significance and a borderline significance (p = 0.0085 and p = 0.0652, respectiely). In addition, the patients with both mdm2(–) and p53(–) showed a signifiant better prognosis as compared with either counterpart of mdm2-p53 category (p < 0.05 for both). Multivariate analysis revealed only pT category and mdm2-p53 category as independent factors for both disease progression and survival. Conclusions: Clinical significance of simultaneous evaluation of mdm2 and p53 immunostaining proved to be superior over that of cell proliferation and/or apoptotic markers when elucidating the biological characteristics of bladder cancer.

Immunohistochemical analysis of proliferating cell nuclear antigen, p53 protein and nm23 protein, and nuclear DNA content in transitional cell carcinoma of the bladder

Transitional cell carcinoma (TCC) of the bladder displays an unpredictable biologic behavior and the morphologic methods of grading tumor malignancy are often insufficient to predict the clinical outcome of patients with TCC of the bladder. Thus, the new indicator should reliably reflect prognosis. In this study, the authors determined the prognostic significance of proliferating cell nuclear antigen (PCNA), p53 protein, and nm23 protein, as well as nuclear DNA content in specimens with TCC of the bladder.

Functional Loss of the γ-Catenin Gene through Epigenetic and Genetic Pathways in Human Prostate Cancer

γ-Catenin is a cell adhesion molecule and a candidate mediator of Wnt signal transduction. We hypothesized that impaired regulation of γ-catenin through genetic and epigenetic pathways is associated with the pathogenesis of prostate cancer. To test this hypothesis, cytosine-phosphate-guanine methylation, loss of heterozygosity (LOH), and mutation status of the γ-catenin gene were analyzed in cultured prostate cancer cell lines, 180 localized prostate cancers, 69 benign prostatic hyperplasias, and 11 hormone refractory prostate cancers (HRPC). In prostate cancer cell lines (DuPro, LNCaP, ND-1, and PC3), γ-catenin mRNA transcripts were increased after 5-aza-2′-deoxycytidine treatment. In localized prostate cancer, γ-catenin expression was lower but prevalence of γ-catenin methylation was higher compared with benign prostatic hyperplasia. However, γ-catenin methylation did not correlate with Gleason sum, pT category, or capsular penetration. Among localized prostate cancers with positive γ-catenin methylation, the presence of LOH at chromosome 17q21 was closely related to down-regulation of γ-catenin mRNA expression. The γ-catenin mutations were not found in localized prostate cancers, whereas six mutations were found in five HRPCs within or close to the GSK-3β consensus motif phosphorylation site, among which four HRPCs showed strong nuclear γ-catenin accumulation. In these four HRPCs, Bcl-2 expression was increased, whereas the target of the Wnt signal, c-myc , was only expressed in one HRPC. Therefore, although epigenetic γ-catenin methylation is an early event in the development of prostate cancer, simultaneous events of epigenetic cytosine-phosphate-guanine methylation and genetic LOH may be responsible for functional loss of γ-catenin. The γ-catenin mutation related to Bcl-2 overexpression has a significant effect on the pathogenesis of HRPC. This is the first report to characterize the epigenetic and genetic regulation of γ-catenin in human prostate cancer.

Postoperative morbidity, functional results and quality of life of patients following orthotopic neobladder reconstruction

Aim: To evaluate postoperative morbidity, functional results and health‐related quality of life of patients with an orthotopic neobladder.

CONGENITAL COLLATERAL URETHRAL DUPLICATION IN THE FRONTAL PLANE

Urethral duplication is rare and usually presents with a double urinary stream, recurrent urinary infection, incontinence or dysuria. Numerous classifications have been described to clarify the different types of urethral duplication. It usually occurs in the sagittal plane where 2 urethras lie behind each other. Although duplex urethras lie collaterally in the frontal plane less commonly, this type of duplication often is associated with midline defects. To our knowledge we report the first case of collateral urethral duplication in the frontal plane with no other congenital anomalies. CASE REPORT

Immunohistochemistry of p53 Protein in Transitional-Cell Carcinoma of the Bladder Using an Image Analyzer

The p53 protein is known to be the product of the tumor suppressor gene p53. To elucidate the biological characteristics of p53 protein in transitional-cell carcinoma (TCC) of the bladder, the positive rate (PR) and positive intensity (PI) of p53 immunostaining in 72 TCCs of the bladder were quantified and compared with clinicopathological findings, prognosis and expression of proliferating-cell nuclear antigen (PCNA). The immunoreactivity for p53 and PCNA was evaluated using the CAS 200 Image Analyzer (Cell Analysis System, Elmhurst, Ill., USA). Intense immunoreactivity for p53 protein was observed not only near the basal cell layer but also at the invasive border. Both PR and PI of p53 were significantly correlated with histological grade (p < 0.05 and P < 0.02, respectively), histological stage (p < 0.02 and p < 0.02, respectively). Both PR and PI of p53 were significantly higher in patients who died of bladder cancer and in patients who developed metastatic progression. Using a univariate analysis, the survival was significantly short in subjects with high PR (> 40%) or high PI (> 70%) of p53 (p < 0.01 in both cases). However, using a multivariate analysis, the prognostic value of p53 immunoreactivity was not superior to histological stage. These findings suggested that, although p53 immunoreactivity appears to be related to proliferative activity in TCCs of the bladder, the prognostic relevance of p53 immunoreactivity was rather limited when evaluating the biological attitude of individual TCC of the bladder.

Blockade of Paclitaxel-Induced Thymidine Phosphorylase Expression Can Accelerate Apoptosis in Human Prostate Cancer Cells

Recently, survival benefit by chemotherapy using paclitaxel (PTX) and the induction of thymidine phosphorylase (TP) by PTX have been reported in several solid tumors. On the other hand, TP confers antiapoptotic effect on tumor cells through inhibition of caspase-8 activation in vitro. On the basis of these previous observations, we hypothesized that (a) TP can be induced after PTX treatment in human prostate cancer (PC) and (b) blockade of PTX-induced TP expression can enhance the apoptotic processes in human PC cells. PTX was used to find TP expression in all eight hormone-refractory PC cases after chemotherapy; however, cleaved caspase-8 was not expressed after chemotherapy in the six hormone-refractory PC cases with strong TP expression. In PC cell lines (PC-3, DU 145, and LNCaP), TP expression after PTX treatment was clearly up-regulated in a dose-dependent manner. Cell viability of PC cell lines treated with PTX and TP antisense was significantly reduced in a time-dependent and dose-dependent manner compared with the PTX treatment alone. Likewise, apoptotic index of PC cells treated with PTX and TP antisense was significantly increased in comparison with PTX alone. After complete blockade of PTX-induced TP translation by TP antisense transfection, cleaved form of caspase-3 and poly(ADP-ribose) polymerase was increased, and this exaggeration of apoptosis also ran parallel with caspase-8 activation in a PTX dose-dependent manner. However, in PC cell lines treated with TP antisense alone, neither caspase-3 nor poly(ADP-ribose) polymerase was cleaved despite caspase-8 activation. These results indicate that PTX-induced TP up-regulation is associated with decreased caspase-8 activation. This study is the first report showing that blockade of PTX-induced TP expression could exaggerate the processing of apoptosis in PC cells treated with PTX. Our results provide preclinical evidence that TP could be a new molecular target for enhancing the potency of PTX-mediated apoptosis in PC cells.