Soluble Fas and Fas-ligand in bladder cancer in vitro and in vivo.

Circulating soluble Fas (sFas) and expression of Fas-ligand on cancer cells are mechanisms of immune escape. The aim of the present study was to investigate expression and production of Fas and Fas-ligand on bladder cancer cell lines of different grade as a basic mechanism of their secretion in vivo. sFas and sFas-ligand serum levels of patients with different stage of bladder cancer were examined to determine the possible clinical use of these molecules as tumor markers. Bladder cancer cell lines RT4 (G1), RT112 (G1), T24 (G3) and SUP (G4) were analyzed by flowcytometry for Fas and Fas-ligand expression. To determine if the Fas-ligand gene is transcribed in these bladder cancer cell lines, RT-PCR was performed on mRNA extracted from these cell lines. Production of sFas and sFas-ligand was examined in cell culture supernatants of the cancer cells as well as in the serum of 62 patients with bladder cancer by a specific ELISA test. We demonstrate that Fas is expressed in similar levels on all human bladder carcinoma cell lines. In T24 (G3) and SUP (G4) cell lines we were able to detect the Fas-ligand protein, whereas no Fas-ligand protein could be found in RT4 and RT112 (G1) cells. Fas-ligand mRNA was expressed in all bladder cancer cell lines. Furthermore, all bladder cancer cell lines produce sFas but no sFas-ligand in spite of mRNA expression. The range of sFas levels in the serum of all patients with bladder cancer was large and did not show a correlation to the histopathological stage of bladder cancer. Although there is in vitro evidence that sFas and Fas-ligand play a role in bladder cancer, no correlation between the sFas and s Fas-ligand serum levels and the histopathological stage of bladder cancer could be found. Therefore, serum sFas and sFas-ligand have to date limited clinical relevance.

Bladder cancer cells acquire competent mechanisms to escape Fas-mediated apoptosis and immune surveillance in the course of malignant transformation.

Mechanisms of resistance against Fas-mediated cell killing have been reported in different malignancies. However, the biological response of immune escape mechanisms might depend on malignant transformation of cancer cells. In this study we investigated different mechanisms of immune escape in 2 well-differentiated low-grade (RT4 and RT112) and 2 poorly differentiated high-grade (T24 and TCCSUP) bladder cancer cell lines. Fas, the receptor of Fas-ligand, is expressed and shedded by human transitional bladder carcinoma cell lines RT4, RT112, T24 and TCCSUP. Cytotoxicity and apoptosis assays demonstrate that in spite of the Fas expression, poorly differentiated T24 and TCCSUP cells are insensitive towards either recombinant Fas-ligand or agonistic apoptosis-inducing monoclonal antibody against Fas. In poorly differentiated T24 and TCCSUP cell lines we were able to detect marked Fas-ligand protein by flow cytometry and Western blot analysis. In grade 1 RT4 and RT112 cells only minor expression of Fas-ligand possibly because of proteinase action. Fas-ligand mRNA translation or post-translational processing seems to be regulated differentially in the cancer cell lines depending on malignant transformation. In co-culture experiments we show that poorly differentiated cells can induce apoptosis and cell death in Jurkat cells and activated peripheral blood mononuclear cells. This in vitro study suggests that bladder cancer cells can take advantage of different mechanisms of immune evasion and become more competent in avoiding immune surveillance during transformation to higher-grade malignant disease.

Circulating intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and E-selectin in urological malignancies.

Several studies suggest that cellular adhesion molecules (CAM) play a role in cancer progression and metastasis. To evaluate the role of these molecules as possible tumor markers in patients with urological malignancies, we examined the serum levels of intercellular cell adhesion molecule-1 (ICAM-1), vascular cellcular adhesion molecule-1 (VCAM-1) and E-selectin in patients with renal cell-, bladder-, prostate- and testicular cancer. Serum levels of 237 patients with urological cancers, renal cell carcinoma (n = 47), bladder cancer (n = 81), prostate cancer (n = 87) and testicular cancer (n = 22) and a group of 41 patients with benign prostate hyperplasia (BPH) as well as a 42 healthy control persons were examined for CAMs by specific ELISA tests. Serum CAM concentrations of all tumor patients were compared with controls and within the group according to T stage, N stage, tumor grade and extent of distant metastasis. Our results demonstrate that ICAM-1 and VCAM-1 serum levels are not stage dependently elevated; in contrary, they demonstrate a wide range and are highly variable throughout the different cancer types. In renal cell cancer and in bladder cancer, there is a significant difference for ICAM-1 between controls and T3 and T4 and metastatic cancers. A similar difference was found for VCAM-1, however not for E-selectin in any tumor group. Testicular cancer and prostate cancer did not demonstrate any difference in CAM serum levels between patients with tumors and controls. In metastatic renal cell-, bladder- and prostate cancer, the serum levels of ICAM-1 and VCAM-1 showed a tendency to correlate with the extent of metastatis although no statistical difference between patients with a single metastatic lesion and patients with multiple lesions could be demonstrated. The results of this study implicate a rather limited role of cellular adhesion molecules. Despite of significant ICAM-1 or VCAM-1 serum levels in some locally advanced tumors or metastatic disease, this observation does not provide enough relevant clinical information for use as tumor markers.

Urinary levels of monocyte chemo-attractant protein-1 correlate with tumour stage and grade in patients with bladder cancer.

OBJECTIVE: To determine if the chemokine monocyte chemo-attractant protein-1 (MCP-1) is produced locally in patients with bladder cancer and to analyse a possible correlation between tumour stage, grade and metastatic spread, and the urinary and systemic levels of MCP-1. PATIENTS SUBJECTS AND METHODS: Urine and serum samples were obtained from 60 patients with bladder cancer and 20 control subjects. Tumour stage, grade, metastasis and nodal status were assessed. MCP-1 levels in serum and urine were determined using a sandwich enzyme-linked immunosorbent assay. Two transitional cell cancer cell lines (grade I and grade III) were analysed for MCP-1 production under normal and nutritive-stress cell culture. RESULTS: The correlation of urinary MCP-1 levels with tumour stage, grade and distant metastasis was highly significant. Patients with stage T2-T4 bladder cancer had three to fourfold higher mean MCP-1 concentrations (pg/mL) in their urine than those with T1 stage tumours or than the controls (controls 260; T1 359; T2 967; T3 917; T4 1829; P < 0.005). A tumour grade of > GI and the existence of distant metastasis (M1) also correlated significantly with higher urinary MCP-1 levels (GI 373; GII 661; GIII 1111; M0 644; M1 1379; P < 0.05). No differences in circulating serum MCP-1 level were detected between controls and patients. The low-grade (GI) RT4 bladder cancer cell line produced only traces of MCP-1, which did not change under nutritional stress; in contrast, the highly malignant T24 bladder cancer cell line (GIII) spontaneously secreted large amounts of MCP-1 (approximately 7000 pg/mL) which increased under nutritive stress to 13,000 pg/mL. CONCLUSION: MCP-1, as a potent monocyte chemo-attractant to tumour sites, is probably produced by bladder cancer cells; MCP-1 levels in the vicinity of the tumour (i.e. urine) correlate significantly with TNM stage and grade. As has already been shown in other neoplasms, the resulting monocyte/macrophage infiltrate possibly facilitates tumour neovascularization and tissue invasion. Therefore, MCP-1 levels in the urine of patients with bladder cancer may be a prognostic marker for the natural course of the disease, and modulation of this chemokine might be a future therapeutic approach for adjuvant treatment of bladder cancer.

Comparative effects of chronic angiotensin-converting enzyme inhibition and angiotensin II type 1 receptor blockade on cardiac remodeling after myocardial infarction in the rat.

BACKGROUND: After myocardial infarction, the noninfarcted left ventricle develops reactive hypertrophy associated with a depressed coronary flow reserve, myocardial interstitial fibrosis, and reduced capillary density. The present study investigated the comparative cardiac effects of chronic angiotensin-converting enzyme (ACE) inhibition and selective angiotensin II type 1 receptor (AT1) blockade in the rat model of myocardial infarction and failure. METHODS AND RESULTS: Seven days after coronary ligation (MI), rats were randomized to enalapril (n = 8; 500 micrograms.kg-1.d-1), losartan (n = 9; 3 mg.kg-1.d-1), or placebo (n = 8) and treated for 6 weeks. Sham-operated rats (n = 10) served as controls. Coronary blood flow was measured with radiolabeled microspheres during baseline and maximal coronary dilation induced by dipyridamole (2 mg.kg-1.min-1 over 10 minutes). Right and left ventricular (LV) weight was increased in infarcted rats compared with sham-operated animals and enalapril- and losartan-treated MI rats. Minimal LV and right ventricular coronary vascular resistance was increased in MI rats but normalized with enalapril and losartan (LV:sham, 8.9; MI-placebo, 12.7; MI-enalapril, 9.2; MI-losartan, 8.8 mm Hg.mL-1.min-1.g-1, all P < .05 versus MI-placebo). Interstitial fibrosis determined from perfusion-fixed hearts was increased in infarcted rats but reduced by both enalapril and losartan. Myocardial capillary density improved with enalapril and losartan. In separate groups treated as above, plasma and tissue ACE activity was determined and demonstrated significantly higher ACE activity in noninfarcted LV tissue of MI-placebo rats compared with sham (0.64 vs 0.27 nmol.mg protein-1.min-1, P < .05). Enalapril and losartan reduced LV ACE activity (0.39 and 0.29 nmol.mg protein-1.min-1, P < .05 versus MI-placebo). CONCLUSIONS: The present study demonstrates that both chronic ACE inhibition and AT1 receptor blockade (1) reduces cardiac hypertrophy, (2) restores minimal coronary vascular resistance in postinfarction reactive hypertrophy, and (3) attenuates the development of myocardial interstitial fibrosis in the noninfarcted LV. These results suggest that inhibition of generation of angiotensin II and AT1 receptor blockade are equally effective in preventing important features of ventricular remodeling after myocardial infarction.