The green tea compound, (-)-epigallocatechin-3-gallate downregulates N-cadherin and suppresses migration of bladder carcinoma cells

Green tea has been reported as potential dietary protection against numerous cancers and has been shown to have activity in bladder tumor inhibition in different animal models. The goal of this study was to examine the effects of (-)-epigallocatechin gallate (EGCG-the major phytochemical in green tea) on growth inhibition and behavior of human bladder carcinoma cells and to identify the altered signaling pathway(s) underlying the response to EGCG exposure. EGCG inhibited the in vitro growth of invasive bladder carcinoma cells with an IC(50) range of 70-87 microM. At a concentration of 20 microM, EGCG decreased the migratory potential of bladder carcinoma cells with concomitant activation of p42/44 MAPK and STAT3 and inactivation of Akt. Using biochemical inhibitors of MAPK/ERK, and siRNA to knockdown STAT3 and Akt, inhibition of migration was recorded associated with Akt but not MAPK/ERK or STAT3 signaling in bladder cells. In addition, EGCG downregulated N-cadherin in a dose-dependent manner where reduction in N-cadherin expression paralleled declining migratory potential. Continuous feeding of EGCG to mice prior to and during the establishment of bladder carcinoma xenografts in vivo revealed >50% reduction in mean final tumor volume (P </= 0.05) with no detectable toxicity. EGCG inhibited bladder carcinoma cell growth and suppressed the in vitro migration capacity of cells via downregulation of N-cadherin and inactivation of Akt signaling. Continuous administration of EGCG to mice revealed significant inhibition of tumor growth in vivo indicating a possible preventative role for green tea in bladder cancer.

Comparing the Gleason prostate biopsy and Gleason prostatectomy grading system: the Lahey Clinic Medical Center experience and an international meta-analysis

BACKGROUND

The accuracy of the prostate biopsy Gleason grade to predict the prostatectomy Gleason grade varies tremendously in the literature.

OBJECTIVES

Determine the accuracy and distribution of the prostate biopsy Gleason grade and prostatectomy Gleason grade at LCMC (Lahey Clinic Medical Center) and worldwide.

DESIGN, SETTING, AND PARTICIPANTS

Participants included 2890 patients who had not received preoperative hormones, and for whom preoperative and postoperative Gleason sums were available. Participants underwent radical prostatectomy at LCMC, an academic referral center, from 1982-2007. Studies for the meta-analysis were selected from Medline: 1994-2007. Search criteria included keywords "Gleason," "biopsy," and "prostatectomy," >/=200 patients, and whether the biopsy and prostatectomy Gleason scores categorized into the predefined Gleason grades. The meta-analysis included 15 studies and the LCMC database for 14,839 total patients.

MEASUREMENTS

Gleason scores 2-6, 7, and 8-10 were converted to low, moderate, and high grade, respectively. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value were calculated. The kappa statistic and chi-square were used to compare biopsy and prostatectomy grades.

RESULTS AND LIMITATIONS

The percentage of patients in whom the prostatectomy grade was accurately predicted, upgraded, and downgraded was 58%, 36%, and 5% at LCMC and 63%, 30%, and 7% in the meta-analysis, respectively. The PPV for low-, moderate-, and high-grade cancer was 54%, 70%, and 60% for LCMC and 62%, 70%, and 50% for the meta-analysis, respectively. The sensitivity decreased with increasing Gleason grade (low, moderate, and high) for LCMC (91%, 38%, 28%) and the meta-analysis (90%, 40%, 33%), respectively. The distribution of low-, moderate-, and high-grade cancer on biopsy (69%, 25%, and 6%) and prostatectomy specimen (47%, 44%, and 9%) demonstrated only "fair" agreement (kappa, 0.37).

CONCLUSIONS

Patients and practitioners need to be cognizant of significant upgrading for low-grade disease and the downgrading for high-grade disease.

Prognostic significance of altered p120 ctn expression in bladder cancer

OBJECTIVE

To identify the frequency of change in the expression and localization of p120(ctn) in bladder tumours and its association with clinical outcomes, and to investigate the potential role of p120(ctn) in the migratory and invasive behaviour of bladder carcinoma cells.

MATERIALS AND METHODS

In all, 425 superficial tumour specimens (Ta, Tis and T1) and 305 invasive (T2-T4) tumour specimens from 534 patients were assembled in 10 tissue microarrays. P120(ctn) immunostaining was scored for intensity and cellular localization and correlated with clinical variables and survival analysis. Knockdown of p120(ctn) was achieved using small-interference RNA (siRNA) followed by the assessment of migration and invasion behaviour in standard in vitro assays.

RESULTS

The expression levels of p120 catenin inversely correlated with pathological tumour stage (P < 0.001), histological grade (P < 0.001), presence of lymphovascular invasion (P = 0.02) but not lymph node (LN) involvement (P = 0.17). Non-membranous localization of p120(ctn) correlated with stage (P < 0.001), grade (P < 0.001), lymphovascular invasion (P = 0.04) and LN-positive disease (P = 0.02). A low expression level of p120(ctn) was linked to a poor outcome in cancer-specific survival analysis. Knockdown of p120(ctn) using siRNA resulted in a significant reduction in the migration and invasive potential of bladder carcinoma cells.

CONCLUSIONS

Our findings suggest that p120(ctn) acts as a prognostic factor in bladder tumours and has a primary role to play in the migratory and invasive behaviour of bladder carcinoma cells.

Epidermal Growth Factor Receptor Status and the Response of Bladder Carcinoma Cells to Erlotinib

PURPOSE

We established the frequency of mutation of the epidermal growth factor receptor in bladder cancer and determined whether the activation status of epidermal growth factor receptor confers sensitivity to erlotinib.

MATERIALS AND METHODS

The identification of mutations in the kinase domain (exons 18-21) of epidermal growth factor receptor was performed using single strand conformation polymorphism. The action of erlotinib was established within a bladder carcinoma cell panel using clonogenic assays and Western blot analysis.

RESULTS

In 112 invasive bladder tumors a total of 6 mutations in 4 patients (3.6%) were identified in exon 21. Erlotinib demonstrated concentration dependent inhibition of growth where three cell lines showed high and 2 showed low sensitivity to the drug. Erlotinib inhibited activation of epidermal growth factor receptor, mitogen activated protein kinase, Akt and STAT3. However, the activation status of Akt was maintained in cell lines that were insensitive to the inhibitory action of erlotinib and were characterized as having undergone epithelial-to-mesenchymal transition.

CONCLUSIONS

Although mutations in the coding region of epidermal growth factor receptor are rare in invasive bladder tumors, differential sensitivity to erlotinib was recorded within a panel of cell lines. Maintenance of the phosphorylation status of Akt in the presence of erlotinib along with epithelial-to-mesenchymal transition correlates with insensitivity to growth inhibition in bladder carcinoma cell lines. Even in the absence of epidermal growth factor receptor mutations erlotinib shows potential as a therapeutic agent for the treatment of bladder cancer.

In vitro analysis of a nanocrystalline silver-coated surgical mesh

BACKGROUND AND PURPOSE

One million nosocomial infections occur each year in patients with prosthetic devices. We analyzed a polypropylene mesh coated with nanocrystalline silver particles (NCSP) as a means of preventing such infections.

METHODS

Nanocrystalline silver was applied to polypropylene mesh using physical vapor deposition in three doses: low (0.31 mg/cm(2)), medium (0.64 mg/cm(2)), and high (1.13 mg/cm(2)). The zone of inhibition (ZOI) test was conducted by incubating either uncoated polypropylene mesh (UM) or silver-coated mesh (CM) with and without various amounts of bovine serum albumin (BSA) and then on agar plates with Staphylococcus aureus and calculating the ZOI. The bactericidal effects of the NCSP-coated meshes were assessed by incubating either UM or CM in medium with S. aureus and performing serial dilutions at 4 and 8 h. Scanning electron microscopy (SEM) was used to examine the surface of UM and CM with and without bacterial incubation.

RESULTS

There was an increasing ZOI for low-, medium-, and high-dose CM and no ZOI for UM (p < 0.001 for all CM compared with UM). Incubating the mesh with various amounts of BSA produced persistent ZOIs with the medium- and high-dose CM; however, the low-dose CM became attenuated by such treatment, with no ZOI being seen with meshes incubated in 10% BSA. All concentrations of CM were bactericidal, as no bacteria grew at 8 h of incubation. The SEM images showed clusters of S. aureus on the surface of UM and no clusters on CM.

CONCLUSIONS

The CM demonstrated significant bactericidal activity compared with UM. Nanocrystalline silver particles may decrease the incidence of postoperative prosthetic mesh infections and be useful as a coating for other prosthetic materials.

Identification and prognostic significance of an epithelial-mesenchymal transition expression profile in human bladder tumors

PURPOSE

Epithelial to mesenchymal transition (EMT) is reportedly an important transition in cancer progression in which the underlying cellular changes have been identified mainly using in vitro models. In this study, we examined the expression pattern of EMT markers in vivo and determined the occurrence and clinical significance of these events in a series of bladder carcinomas.

EXPERIMENTAL DESIGN

Eight hundred and twenty-five tumor samples from 572 bladder cancer patients were assembled in 10 tissue microarrays. Paraffin sections from each tissue microarray were subjected to antigen retrieval and processed by immunohistochemistry for the expression of E-cadherin, plakoglobin, beta-catenin, N-cadherin, and vimentin.

RESULTS

Pathologic expression of E-cadherin, beta-catenin, plakoglobin, and vimentin were associated with the clinicopathologic variables of grade and stage with only the cytoplasmic localization of plakoglobin found associated with lymph node status. Associations between the aforementioned markers were found significant as determined by the Spearman correlation coefficient with N-cadherin showing no associations in this analysis. In univariate survival analysis involving patients who underwent cystectomy, the reduction or loss of plakoglobin significantly influenced overall survival (P = 0.02) in which the median time to death was 2 years compared with 4 years when a normal level of plakoglobin was recorded. When the analysis was done for cancer-specific survival, low levels of both plakoglobin (P = 0.02) and beta-catenin (P = 0.02) significantly influenced survival.

CONCLUSION

The putative markers of EMT defined within a panel of bladder carcinoma cell lines were recorded in vivo, frequently associated with tumors of high grade and stage. Although multivariate analysis showed no significant influence of the EMT biomarkers on survival, alterations associated with plakoglobin were identified as significant prognostic features in these tumors.

Ischemic nephropathy

Ischemic nephropathy is an independent pathway towards end-stage renal disease. Its prevalence is estimated to be significant and increasing among populations with vascular disease, hypertension, and chronic renal failure. Angiography remains the gold standard for evaluation of ischemic nephropathy; however, selection by clinical criteria and noninvasive screening with ultrasound are recommended for most patients. Surgical revascularization of ischemic kidneys can halt or reverse deterioration of renal function and is preferable to medical treatment. Direct comparison of angioplasty and stent placement with surgery is needed.

DNA Integrity Assay: A Plasma-Based Screening Tool for the Detection of Prostate Cancer

PURPOSE

The aim of this study was to evaluate the utility of the DNA integrity assay (DIA) as a plasma-based screening tool for the detection of prostate cancer.

EXPERIMENTAL DESIGN

Blood samples were collected from patients with biopsy-proven prostate cancer prior to prostatectomy (n = 123) and processed as two-spin plasma preparations. The three control groups included: males <40 years old with no history of cancer (group 1, n = 20); cancer-free postprostatectomy patients (group 2, n = 25), and patients with a negative prostate biopsy (group 3, n = 22). DNA in plasma preparations were isolated, hybrid-captured, and DNA fragments (200 bp, 1.3, 1.8, and 2.4 kb) were multiplexed in real-time PCR. A baseline cutoff was determined for individual fragment lengths to establish a DIA score for each patient sample.

RESULTS

Patients with prostate cancer (86 of 123; 69.9%) were determined to have a positive DIA score of >or=7. The DIA results from control groups 1, 2, and 3 showed specificities of 90%, 92%, and 68.2%, respectively. Of the patients with negative age-adjusted prostate-specific antigen (PSA) and prostate cancer, 19 of 30 (63%) had a positive DIA score. The area under the receiver operating characteristic curve for DIA was 0.788.

CONCLUSION

While detecting 69.9% of those with prostate cancer, DIA maintained an overall specificity of 68.2% to 92%, a range favorably comparable to that currently accepted for PSA (60-70%). The variability in specificity between control groups is likely explained by the established 19% to 30% detection of prostate cancer on subsequent biopsies associated with control group 3. DIA detected 63% of the prostate cancers undetected by currently accepted PSA ranges.

Management of renal cell carcinoma with vena cava and atrial thrombus: minimal access vs median sternotomy with circulatory arrest

OBJECTIVE

To review our experience with approaches for managing renal cell carcinoma (RCC) with venous thrombi extension at and above the level of the hepatic veins, comparing surgery and peri-operative outcomes in patients with cardiopulmonary bypass (CPB) with deep hypothermic cardiac arrest (DHCA) either by minimal access (MA) or traditional median sternotomy (TMS).

PATIENTS AND METHODS

From 1986 to 2005, 50 radical nephrectomies with inferior vena cava (IVC) thrombectomies were performed at our institution using TMS (22 patients) and MA (28) techniques. Patient demographics were compared using Student's t-, Fisher's exact and Pearson chi-square tests. The duration of surgery, CPB, DHCA, mechanical ventilation, length of stay, and peri-operative transfusion requirements, were compared using the Mann-Whitney U-test. Estimates of survival were constructed using Kaplan-Meier curves and analysed with the log-rank test. Subgroups were analysed excluding TMS patients undergoing concurrent coronary revascularization.

RESULTS

There were no significant differences in patient demographics or comorbidities between the MA and TMS group. There were significant decreases in the MA vs the TMS group (P < 0.05) in the duration of surgery, mechanical ventilation, length of stay and peri-operative transfusion requirements. When patients with coronary revascularization were excluded, the MA group had significant decreases (P < 0.05) in duration of surgery, hospital stay and transfusion requirements. Peri-operative mortality was not statistically different between the TMS (14%) and MA (4%) patients. Overall and organ system-specific complications also were not statistically different. The overall median survival in the TMS and MA groups was 0.62 and 2.84 years, respectively (P = 0.06, hazard ratio 2.02; 95% confidence interval, CI, 0.97-4.72). Patients with tumour thrombus extending into the right atrium had a median survival of 1.02 years, vs 2.84 years with no intracardiac extension (P = 0.15, hazard ratio 1.82, 95% CI 0.81-4.0).

CONCLUSIONS

MA surgical techniques in conjunction with DHCA for the treatment of RCC with extensive tumour thrombus provides quicker surgery and a shorter hospital stay. In addition there was less requirement for mechanical ventilation and transfusion than with TMS. Our findings suggest that MA techniques provide significant advantages over TMS.

The Use of Bowel for Ureteral Replacement for Complex Ureteral Reconstruction: Long-Term Results

PURPOSE

Ileal and intestinal ureteral replacement remains a useful procedure for complex ureteral reconstruction. We examined the long-term safety and efficacy of this procedure, especially in regard to maintaining preoperative renal function and the avoidance of major complications.

MATERIALS AND METHODS

A total of 56 patients underwent intestinal ureteral substitution at our institution between 1979 and 2003, including 52 with an ileal ureteral replacement, 2 with colonic replacement alone and 2 with bilateral ureteral replacement, necessitating ileum and colon for 1 ureter each. The factors reviewed were indications for surgery, type of ureteral replacement, and the presence and type of complications. Followup data included excretory urogram or equivalent imaging results, and measurement of serum chloride, bicarbonate and creatinine before and after the procedure.

RESULTS

Overall the complication rate remained low. Mean followup was 6.04 years (median 3.2). Most postoperative complications, which occurred in 10 patients (17.9%), were minor in nature, including pyelonephritis, fever of unknown origin, neuroma, hernia, recurrent urolithiasis and deep venous thrombosis. Major complications occurred in 6 patients (10.5%), including anastomotic stricture, ileal graft obstruction, wound dehiscence and chronic renal failure. Overall patients did not experience worsening renal function after the procedure with equivalent median creatinine before and after the procedure (1.0 mg/dl).

CONCLUSIONS

During long-term followup major complications are rare and renal function remains preserved. Ileal and intestinal ureteral substitution remains a safe and efficacious procedure in patients with complex and difficult ureteral issues not amenable to more conservative measures.

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Restoration of plakoglobin expression in bladder carcinoma cell lines suppresses cell migration and tumorigenic potential

The reduction or loss of plakoglobin expression in late-stage bladder cancer has been correlated with poor survival where upregulation of this catenin member by histone deacetylase inhibitors has been shown to accompany tumour suppression in an in vivo model. In this study, we directly addressed the question of the role of plakoglobin in bladder tumorigenesis following restoration, or knockdown of expression in bladder carcinoma cell lines. Restoration of plakoglobin expression resulted in a reduction in migration and suppression of tumorigenic potential in vivo. Immunocytochemistry revealed cytoplasmic and membranous localisation of plakoglobin in transfectants with <1% of cells displaying detectable nuclear localisation of plakoglobin. siRNA knockdown experiments targeting plakoglobin, revealed enhanced migration in all cell lines in the presence and absence of E-cadherin expression. In bladder cell lines expressing low levels of plakoglobin and desmoglein-2, elevated levels of desmoglein-2 were detected following restoration of plakoglobin expression in transfected cell lines. Analysis of wnt signalling revealed no activation event associated with plakoglobin expression in the bladder model. These results show that plakoglobin acts as a tumour suppressor gene in bladder carcinoma cells and the silencing of plakoglobin gene expression in late-stage bladder cancer is a primary event in tumour progression.

Analysis of peripheral blood for prostate cells after autologous transfusion given during radical prostatectomy

OBJECTIVES

To determine if cells expressing prostate-specific antigen (PSA) can be detected in blood collected by a cell-saver during radical prostatectomy (RP) or in the peripheral blood after intraoperative autotransfusion (IAT).

PATIENTS AND METHODS

In all, 112 men with clinical T1c-T2 prostate cancer undergoing RP were prospectively assessed. A cell-saver system was used in each to collect blood from the surgical field after prostate manipulation. IAT was given based on clinical indications. Standardized peripheral blood samples were collected from patients before RP, in the recovery room afterward, and at 3-5 weeks after surgery. A reverse-transcriptase-polymerase chain reaction assay for PSA mRNA was used to detect prostate cells in cell-saver and peripheral blood samples. Patients were followed after surgery with PSA measurements to assess biochemical failure.

RESULTS

PSA-expressing cells were detected in 88% of cell-saver reservoir and 13% of preoperative blood samples. No PSA-expressing prostate cells were detected in any peripheral blood samples collected 3-5 weeks after surgery. Analysis of data with 40 months of follow-up showed IAT was not an independent predictor of biochemical failure in multivariate analysis.

CONCLUSIONS

Although IAT blood contains PSA-expressing cells, none could be detected 3-5 weeks after surgery. IAT during RP was not associated with a greater risk of biochemical failure.

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

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

The Lahey clinic experience with continent urinary diversion

OBJECTIVE

To compare the morbidity, mortality and clinical outcome of catheterizable continent urinary reservoirs (CUR) with orthotopic neobladders (ONB) at our institution.

PATIENTS AND METHODS

Between September 1985 and October 2001, 238 patients (84 women and 154 men) had a continent urinary diversion, including 125 ONBs and 113 CURs. The charts of these patients were reviewed retrospectively and the patients interviewed by telephone when possible (for continence data and overall satisfaction). Over the 16 years the relative frequency of ONB diversion increased steadily and thus the mean follow-up was significantly longer for the CUR (9.4 years) than for the ONB group (5.2 years) (P < 0.001). This bias was addressed by comparing these large groups for the early outcome only. Separately, the long-term outcome was analysed, comparing the 40 most recently constructed CURs with all 113 ONBs; this gave a mean follow-up of 5.2 years for ONB and 5.9 years for CUR (not significant, P = 0.23).

RESULTS

Of the 238 continent diversions, 125 were ONBs and 113 CURs; most patients had a diagnosis of transitional cell carcinoma before surgery. The mean age at surgery was 59.1 years for the ONB and 54.8 years for the CUR group (P < 0.001). Men were significantly more likely than women to have had an ONB. There were two deaths after surgery in the ONB and none in the CUR group. The hospital stay was significantly longer for the CUR than for the ONB group; the likelihood of an intensive care unit stay, estimated blood loss and reoperation rate were higher in the CUR group. There was no significant difference in the rates of short-term (<30 days) complications. The analysis of the time-controlled groups showed significantly more long-term (>30 days) complications and of reoperation in the CUR group. Fifty-one patients with ONB and 19 with CURs were contacted by telephone; of those with an ONB, 43 (84%) had daytime continence (<1 pad/day) while 13 (25%) were continent at night (<1 pad). Fifteen of 19 with a CUR reported full day and night-time continence. From separate telephone interviews, overall satisfaction was high for both groups (mean 4.5, scale 0-5), expectations were met in 92% for both, and 94% in both would choose the same procedure again if confronted with the same set of circumstances.

CONCLUSIONS

Both ONB and CUR offer an excellent functional outcome, as reflected by patient satisfaction and continence rates.

Novel expression of N-cadherin elicits in vitro bladder cell invasion via the Akt signaling pathway

Novel N-cadherin expression has been linked to the invasive phenotype in bladder tumors yet a primary role for N-cadherin in invasion has not been defined in this model. To address this, N-cadherin was stably transfected into E-cadherin expressing bladder carcinoma cells. This resulted in an enhanced invasive capacity in in vitro assays that was blocked by incubation with an N-cadherin function-blocking antibody in a dose-dependent manner. Analysis of the signaling pathway(s) implicated in N-cadherin-mediated invasion in bladder carcinoma cell lines revealed no correlation between MAPK signaling and invasion, in the presence or absence of fibroblast growth factor 2. Also, while MAPK and p38 kinase inhibitors did not alter the invasive behavior of these cells, an increase in the phosphorylation of Akt at serine-473 was detected in N-cadherin transfectants, suggestive of N-cadherin-mediated Akt activation in bladder cell invasion. Incubation of N-cadherin transfectants with either PI3 kinase or Akt inhibitors resulted in a significant decrease in the invasive capacity of these cells. Exposure of cells to PP2, a src family kinase inhibitor, also decreased the invasive potential of N-cadherin transfectants and resulted in reduced phosphorylation of Akt. The involvement of Akt signaling in bladder cell invasion was also supported by the inhibition of bladder cell invasion by cells constitutively expressing an activated Akt kinase, using the PI3 kinase and Akt inhibitors and PP2. These results suggest that activation of PI3/AKT kinase following N-cadherin expression contributes to the increased invasive potential of bladder carcinoma cells.