Hayato Yamamoto

MUC1 carrying core 2 O-glycans functions as a molecular shield against NK cell attack, promoting bladder tumor metastasis

Core 2 β-1,6-N-acetylglucosaminyltransferase (C2GnT) forms an N-acetylglucosamine branch in O-glycans (core 2 O-glycans) of cell surface glycoproteins. C2GnT-expressing bladder tumors acquire highly metastatic phenotypes by surviving longer in host blood circulation. However, the detailed mechanisms underlying this increased survival remain unclear. In this study, we report that the expression of C2GnT in bladder tumors positively correlates with tumor progression and that bladder tumor cell-surface mucin 1 (MUC1) carrying core 2 O-glycans plays an important role in the evasion from natural killer (NK) cell attack. In C2GnT-expressing bladder tumor cells, heavily core 2 O-glycosylated MUC1 carries poly-N-acetyllactosamine in its O-glycans and galectin-3 binds to MUC1 through this poly-N-acetyllactosamine. The binding of galectin-3 to poly-N-acetyllactosamine in MUC1 core 2 O-glycans attenuates the interaction of the tumor cells with NK cells and interferes with the access of tumor necrosis factor-related apoptosis-inducing ligand to the tumor cell surface. These effects of MUC1 carrying core 2 O-glycans on NK cell attack facilitate C2GnT-expressing tumor cells to evade NK cell immunity and survive longer in host blood circulation. We reveal that MUC1 carrying core 2 O-glycans thus functions as a molecular shield against NK cell attack, thereby promoting bladder tumor metastasis.

Core 2 N-acetylglucosaminyltransferase-1 expression induces aggressive potential of testicular germ cell tumor.

We studied orchiectomy specimens from 130 patients immuhistochemically with testicular germ cell tumor (TGCT) using anti‐core 2 N‐acetylglucosaminyltransferase‐1 (C2GnT‐1) antibody. The incidence of C2GnT‐1 positivity in stage I disease (29.5%, 21/71) was significantly lower than that in higher stages (84.7%, 50/59) (P < 0.001, χ2 test). This significant difference was also found when the cases were divided into seminoma and NSGCT according to histopathological classification. Kaplan‐Meier plots and the log rank test showed that in the patients with stage I seminoma, C2GnT‐1‐positive cases had a higher risk for recurrence (P < 0.001). This was also the case with the patients with stage I NSGCT (P < 0.001). To determine whether C2GnT‐1 promotes aggressive behavior of cancer cells, a C2GnT‐1‐negative human TGCT cell line, JKT‐1, was stably transfected with a mammalian expression vector containing C2GnT‐1 cDNA. In vitro assays revealed that JKT‐1‐C2 cells are more invasive than mock transfectants, although there are no differences in proliferation activity. When orthotopically inoculated into athymic nude mice, JKT‐1‐C2 cells produced larger testicular tumors extending to the retroperitoneum with mesenteric metastasis, while mock transfectants produced small tumors without metastasis (P < 0.01, Mann‐Whitneys U‐test). When injected via the tail vein, JKT‐1‐C2 cells produced a number of metastatic lung foci. In contrast, mock transfectants produced a small number of nodules (p < 0.01, Mann‐Whitneys U‐test). These results strongly suggest that C2GnT‐1 enhances the metastatic potential of TGCT and may be a reliable biomarker for aggressive potential of TGCT.

Core2 O-glycan-expressing prostate cancer cells are resistant to NK cell immunity.

Core2 β-1,6-N-acetylglucosaminyltransferase (C2GnT) forms an N-acetylglucosamine branch in the O-glycans (core2 O-glycans) of cell surface glycoproteins. We previously revealed that the expression of C2GnT is positively correlated with poor prognosis in prostate cancer patients. However, the detailed mechanisms underlying their poor prognosis remain unclear. In the current study, we report that the core2 O-glycans carried by the surface MUC1 glycoproteins of prostate cancer cells play an important role in the evasion of NK cell immunity. In C2GnT-expressing prostate cancer cells, the MUC1 core2 O-glycans are modified with poly-N-acetyllactosamine. MUC1 glycoproteins carrying poly-N-acetyllactosamine attenuated the interaction of the cancer cells with NK cells, resulting in decreased secretion of granzyme B by the NK cells. Poly-N-acetyllactosamine also interfered with the ability of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) to access the cancer cell surface. These effects of poly-N-acetyllactosamine on NK cells render C2GnT-expressing prostate cancer cells resistant to NK cell cytotoxicity. By contrast, C2GnT-deficient prostate cancer cells carrying a lower amount of poly-N-acetyllactosamine than the C2GnT-expressing prostate cancer cells were significantly more susceptible to NK cell cytotoxicity. Our results strongly suggest that C2GnT-expressing prostate cancer cells evade NK cell immunity and survive longer in the host blood circulation, thereby resulting in the promotion of prostate cancer metastasis.

Effect of an Oral Adsorbent, AST-120, on Dialysis Initiation and Survival in Patients with Chronic Kidney Disease

The oral adsorbent AST-120 has the potential to delay dialysis initiation and improve survival of patients on dialysis. We evaluated the effect of AST-120 on dialysis initiation and its potential to improve survival in patients with chronic kidney disease. The present retrospective pair-matched study included 560 patients, grouped according to whether or not they received AST-120 before dialysis (AST-120 and non-AST-120 groups). The cumulative dialysis initiation free rate and survival rate were compared by the Kaplan-Meier method. Multivariate analysis was used to determine the impact of AST-120 on dialysis initiation. Our results showed significant differences in the 12- and 24-month dialysis initiation free rate (P < 0.001), although no significant difference was observed in the survival rate between the two groups. In conclusion, AST-120 delays dialysis initiation in chronic kidney disease (CKD) patients but has no effect on survival. AST-120 is an effective therapy for delaying the progression of CKD.

Requirement for FBP17 in invadopodia formation by invasive bladder tumor cells.

PURPOSE Invadopodia (protrusions of the plasma membrane formed by invasive tumor cells) have an essential role in bladder tumor invasion. To understand the process of bladder tumor invasion it is crucial to investigate the molecular mechanisms of invadopodia formation. We found that invasive bladder tumor cells express FBP17. In this study we examined the role of FBP17 in bladder tumor cell invadopodia formation and invasion. MATERIALS AND METHODS We used the 3 bladder tumor cell lines YTS-1, T24 and RT4 (ATCC®), and primary culture of bladder tumors from patients. Cells were stained with phalloidin for invadopodia formation. FBP17 knockdown cells were tested for invadopodia formation and subjected to invasion assay using a Transwell® cell culture chamber. We also examined the role of the extended FER-CIP4 homology and Src homology 3 domains of FBP17 in invadopodia formation in FBP17 mutant constructs. RESULTS Invadopodia formation was observed in invasive bladder tumor cells and FBP17 was localized to invadopodia in invasive cells. FBP17 knockdown decreased invadopodia formation in invasive cells to 13% to 14% (p <0.0005) and decreased their invasive capacity to 14% to 16% (p <0.001). The extended FER-CIP4 homology and Src homology 3 domains of FBP17 were necessary for invadopodia formation and invasion. CONCLUSIONS Invadopodia formation requires membrane deformation activity and recruitment of dynamin-2 mediated by FBP17. FBP17 has a critical role in the process of bladder tumor cell invasion by mediating invadopodia formation.

Minimum incision endoscopic radical cystectomy in patients with malignant tumors of the urinary bladder: Clinical and oncological outcomes at a single institution

AIMS The objectives of this study were to investigate the clinical and oncological outcomes of patients with malignant tumors of the urinary bladder undergoing minimum incision endoscopic radical cystectomy (MIE-RC). METHODS Between August 2005 and June 2011, 130 consecutive patients at Hirosaki University Hospital underwent MIE-RC and bilateral lymphadenectomy for malignant tumors of the urinary bladder. We retrospectively studied all 130 patients. MIE-RC was performed through a 7-cm suprapubic midline incision. A 30° laparoscope was conveniently positioned on the head side of the patients, for precise observation and monitoring. RESULTS The median operative time for all procedures, including MIE-RC, bilateral pelvic lymphadenectomy and urinary diversion was 266 min. The median estimated blood loss was 1260 mL. None of the patients had positive surgical margins. The post-operative median follow-up period was 32.8 months. The 5-year overall and disease-free survival rates were 91.6% and 87.0%, respectively. CONCLUSIONS Our experience with MIE-RC appears to be favorable with acceptable operative and oncological outcomes.

Invadopodia formation by bladder tumor cells.

A major cause of death in patients with bladder tumors is recurrence with metastasis. Bladder tumor metastasis is largely dependent upon the invasive capacity of tumor cells. Tumor cell invasion is mainly mediated by actin-rich protrusive membrane structures called invadopodia. The formation of invadopodia was observed in various types of invasive tumors such as breast cancer and melanomas. However, invadopodia formation so far has not been described in bladder tumor cells. We here report that human bladder tumor cells form functionally active invadopodia. By using a confocal laser scanning microscope, we demonstrated that invasive bladder tumor cell lines, YTS-1 and T24, with high Matrigel degradation activity form invadopodia but that noninvasive bladder tumor cell lines, RT4 and KK-47, form no detectable invadopodia. Invadopodia formed by YTS-1 cells had the ability to secrete matrix metalloproteases and degrade extracellular matrix to invade surrounding areas. Moreover, we observed that primary tumor cells obtained from patients with invasive bladder tumors also form invadopodia, validating the results from bladder tumor cell lines. Our results provide evidence that invasive human bladder tumor cells form invadopodia for tumor invasion.

Significance of preoperative butyrylcholinesterase as an independent predictor of survival in patients with muscle-invasive bladder cancer treated with radical cystectomy

OBJECTIVES Butyrylcholinesterase (BChE) is an alpha-glycoprotein found in the nervous system and liver. Its serum level is reduced in many clinical conditions, such as liver damage, inflammation, injury, infection, malnutrition, and malignant disease. In this study, we analyzed the potential prognostic significance of preoperative BChE levels in patients with muscle-invasive bladder cancer (MIBC) undergoing radical cystectomy (RC). METHODS AND MATERIALS We retrospectively evaluated 327 patients with MIBC who underwent RC from 1996 to 2013 at a single institution. Serum BChE level was routinely measured before operation in all patients. Covariates included age, gender, preoperative laboratory data (anemia, BChE, lactate dehydrogenase, and C-reactive protein), clinical T (cT) and N stage (cN), tumor grade, and RC with/without neoadjuvant chemotherapy. Univariate and multivariate analyses were performed to identify clinical factors associated with overall survival (OS) and disease-free survival (DFS). Univariate analyses were performed using the Kaplan-Meier and log-rank methods, and the multivariate analysis was performed using a Cox proportional hazard model. RESULTS The median BChE level was 187 U/l (normal range: 168-470 U/l). The median age of the enrolled patients was 69 years, and the median follow-up period was 51 months. The 5-year OS and DFS rates were 69.6% and 69.3%, respectively. The 5-year OS rates were 90.1% and 51.3% in the BChE ≥ 168 and<168 U/l groups, respectively (P<0.001). The 5-year DFS rates were 83.5% and 55.4% in the BChE ≥ 168 and ≤167 U/l groups, respectively (P<0.001). In the univariate analysis, BChE, cT, cN, and RC with/without neoadjuvant chemotherapy were significantly associated with both OS and DFS. Multivariate analysis revealed that BChE was the factor most significantly associated with OS, and BChE, cT, and cN were significantly associated with DFS. CONCLUSIONS This study validated preoperative serum BChE levels as an independent prognostic factor for MIBC after RC.

Risk factors for erectile dysfunction in healthy Japanese men.

The aim of this study was to identify risk factors for erectile dysfunction (ED) in healthy men. A comprehensive risk factor investigation was carried out in a Japanese community. The subjects were 280 healthy male volunteers with an average age of 56 years (range: 20-83 years) who participated in the Iwaki Health Promotion Project in 2006. They were residents of Iwaki district, Hirosaki City, in northern Japan. The participants completed the five-item version of the International Index of Erectile Function (IIEF-5) and the International Prostate Symptom Score (I-PSS) surveys at the site of examination. We measured blood pressure and brachial-ankle pulse wave velocity (baPWV). We also measured risk factors for metabolic syndrome and sex hormones. We compared these risk factors with the IIEF-5 scores. Ninety-five participants (34%) scored 11 points or fewer on the IIEF-5 survey (severe/moderate ED), 154 (55%) scored 12-21 points (mild ED) and 31 (11%) scored 22 points or more (no ED). The prevalence of ED in the Japanese rural community was 89% (249/280). The severe/moderate ED group had significantly higher total I-PSS scores (p = 0.001), baPWV values (p < 0.001) and systolic blood pressure (p < 0.001) than the mild/no ED group. The same group had significantly lower free testosterone (p < 0.001) and dehydroepiandrosterone sulphate (p < 0.001) than the mild/no ED group. Logistic regression analysis revealed significant differences in baPWV (p = 0.003), total I-PSS (p = 0.015) and free testosterone (p = 0.003). Lower urinary tract symptoms, baPWV and free testosterone are independent risk factors for ED in healthy Japanese men.

Safety and effectiveness of neoadjuvant luteinizing hormone-releasing hormone agonist plus low-dose estramustine phosphate in high-risk prostate cancer: a prospective single-arm study

Background:Radical prostatectomy (RP) has limited cancer control potential for the patient with high-risk prostate cancer (Pca). We prospectively examined the efficacy and safety of neoadjuvant therapy with luteinizing hormone-releasing hormone (LHRH) agonist + low-dose estramustine phosphate (EMP) (LHRH+EMP) followed by RP.Methods:High-risk Pca was defined by the D’Amico stratification system. A total of 142 patients with high-risk Pca were enrolled in this trial from September 2005 to March 2011. The LHRH+EMP therapy included administration of LHRH agonist and 280 mg day–1 EMP for 6 months before RP. Pathological cancer-free (pT0) rate on the surgical specimen was the primary end point. Secondary end points were PSA-free survival and toxicity.Results:The average patient age was 67.4 years (interquartile range (IQR) 72, 65) and the median initial PSA level was 14.80 ng ml–1 (IQR 26.22, 7.13). The median Gleason score was 9 (IQR 9, 7) and 97 patients (68.3%) had clinical stage T2c or T3. All patients completed 6 months of LHRH+EMP neoadjuvant therapy with no delays in RP. Seven patients (4.9%) achieved pT0. Surgical margins were negative in 125 patients (87.0%). At a median follow-up period of 34.9 months, PSA-free survival was 84.3%. No serious adverse events were reported during the study and there were no toxicity-related deaths.Conclusions:Six months of LHRH+EMP neoadjuvant therapy followed by RP is safe and oncological outcomes are acceptable. Although this study was a single-arm trial with a relatively short follow-up, this treatment may have a potential to improve PSA-free survival in high-risk Pca patients. Further clinical trials are warranted.