Variations of components of the plasminogen activation system with the cell cycle in benign prostate tissue and prostate cancer.

Background: Components of the fibrinolytic system are involved in tumor cell invasion and metastasis. Previous investigations suggested a cell cycle-dependent expression of urokinase-type plasminogen activator (u-PA) in epithelial cells. In order to determine a correlation of cell cycle phases with the fibrinolytic system, we investigated the expression of u-PA, tissue-type plasminogen activator (t-PA), and plasminogen activator inhibitor type 1 (PAI-1) in normal and tumor-containing prostate extracts and analyzed a possible relationship with flow cytometry-determined proliferative activity of the samples. Cell cycle phases were correlated with fibrinolytic parameters in prostate tissue. Methods: Samples were obtained from patients undergoing radical prostatectomy for prostate cancer and separated into two portions for DNA analysis and the detection of u-PA, t-PA, and PAI-1. Flow cytometric analysis was performed according to the Vindelov technique. The concentrations of u-PA, t-PA, and PAI-1 were determined from tissue extracts after homogenization by an enzyme-linked immunosorbent assay (ELISA) technique. Results: Correlations of u-PA and t-PA expression with the frequency of G0/G1, S, G2M, S-phase fraction (SPF), and proliferation index (PI) for normal prostate and prostate cancer revealed no significant correlation. The only significant finding was observed in normal tissue revealing a positive correlation between PAI-1 expression and G0/G1 and a negative correlation with S-phase, SPF, and PI. No dependence of PAI-1 expression on different cell phases was found in prostate cancer. Furthermore, no significant correlation of u-PA, t-PA, and PAI-1 with cell cycles in organ-confined ( or = pT3a) tumors was found. No significant correlation in prostate cancer of components of the fibrinolytic system differentiated according to tumor grade or perineural tumor infiltration and cell cycle analysis was found. Only in highly differentiated G1 (Gleason 2-4) cancer, u-PA had a significant positive correlation with G2M-phase. Conclusion: Absence of a correlation between levels of components of the fibrinolytic system and cell cycle phases suggests that the reported association between increases of some of these components and aggressive biological behavior of prostate cancer is secondary to non-cell cycle-related mechanisms.     

Fatty acid regulation of protein kinase C isoforms in prostate cancer cells

Polyunsaturated fatty acids influence the aetiology of prostate cancer. Their effects on cellular mechanisms regulating prostate tumorigenesis are unclear. Using prostate cancer cells (LNCaP), we determined effects of n-9-OA, n-6-LA, and n-3-EPA on total PKC and its isoforms in relation to cell proliferation and PSA production. PKC-alpha, delta, gamma, iota, mu, and zeta were present in LNCaP cells; PKC-beta, epsilon, eta, and theta isoforms were not. PKC-alpha was detected only in cytosol; PKC-delta, iota, gamma, and mu were present in cytosol and in membranes. Fatty acids increased cell proliferation, total PKC activity and elicited pro-proliferative effects on specific PKC isoforms (PKC-delta and -iota). EPA and LA increased total PKC activity and reduced membrane-abundance of PKC-delta. OA reduced cytosolic and membrane PKC-delta. Only EPA reduced PKC-gamma membrane abundance. Fatty acids enhanced cytosolic PKC-iota abundance but only EPA and to a lesser extent LA increased its membrane content. Changes in PKC-delta, -iota, and -gamma did not affect PSA production.     

Effects of lycopene supplementation in patients with localized prostate cancer

Epidemiological studies have shown an inverse association between dietary intake of lycopene and prostate cancer risk. We conducted a clinical trial to investigate the biological and clinical effects of lycopene supplementation in patients with localized prostate cancer. Twenty-six men with newly diagnosed prostate cancer were randomly assigned to receive a tomato oleoresin extract containing 30 mg of lycopene (n = 15) or no supplementation (n = 11) for 3 weeks before radical prostatectomy. Biomarkers of cell proliferation and apoptosis were assessed by Western blot analysis in benign and cancerous prostate tissues. Oxidative stress was assessed by measuring the peripheral blood lymphocyte DNA oxidation product 5-hydroxymethyl-deoxyuridine (5-OH-mdU). Usual dietary intake of nutrients was assessed by a food frequency questionnaire at baseline. Prostatectomy specimens were evaluated for pathologic stage, Gleason score, volume of cancer, and extent of high-grade prostatic intraepithelial neoplasia. Plasma levels of lycopene, insulin-like growth factor-1, insulin-like growth factor binding protein-3, and prostate-specific antigen were measured at baseline and after 3 weeks of supplementation or observation. After intervention, subjects in the intervention group had smaller tumors (80% vs 45%, less than 4 ml), less involvement of surgical margins and/or extra-prostatic tissues with cancer (73% vs 18%, organ-confined disease), and less diffuse involvement of the prostate by high-grade prostatic intraepithelial neoplasia (33% vs 0%, focal involvement) compared with subjects in the control group. Mean plasma prostate-specific antigen levels were lower in the intervention group compared with the control group. This pilot study suggests that lycopene may have beneficial effects in prostate cancer. Larger clinical trials are warranted to investigate the potential preventive and/or therapeutic role of lycopene in prostate cancer.     

The role of the urologist in treating patients with hormone-refractory prostate cancer

Objectives: To ascertain what percentage of urologists' oncology practice is dedicated to the care of prostate cancer patients and to determine urologists' attitudes towards the treatment of patients with metastatic and hormone-refractory prostate cancer (HRPC). An additional objective is to determine urologists' interest in administering various types of chemotherapy in HRPC patients.Materials and Methods: The American Urological Association (AUA) directory of practicing urologists was obtained, and 3000 randomly selected members of the AUA, as well as the complete list of 168 Society of Urologic Oncology (SUO) members, were chosen for the mailing of a 16-item questionnaire. The urologists were asked about how many of their patients have prostate cancer, how many have metastatic disease, and how many have HRPC and are currently receiving intravenous (IV) chemotherapy. In addition, the urologists were queried regarding their level of interest in learning about chemotherapy options as well as learning how to administer chemotherapy.Results: A total of 654 survey questionnaires were completed and returned for tabulation, resulting in a 21% effective response rate. Sixty-four percent of the responding urologists' cancer patients had prostate cancer, 21% had metastatic disease, and 19% had HRPC; only 4% of the urologists currently administer IV chemotherapy themselves. When asked to describe their interest in learning how to deliver and be reimbursed for IV chemotherapy, 26% expressed an extremely low level of interest, 23% a low level of interest, 31% a high level of interest, and 17% an extremely high level of interest. The results of other questions are presented and correlated with the number of years the urologists have been in practice and other demographic data.Conclusions: The management of prostate cancer comprises a major portion of urologists' practices. Almost one half (48%) of the urologists in this survey were interested in administering and being reimbursed for IV chemotherapy. Several chemotherapy regimens have been shown to improve quality of life in patients with HRPC, yet only about 30% of these patients were referred for chemotherapy. If more urologists were able to deliver these drugs, then the number of patients referred for chemotherapy would likely increase, as would accrual to important clinical trials in HRPC. The results of this survey suggest that methods to implement the training and reimbursement of urologists in the use of chemotherapy regimens should be investigated.     

Humoral immunity following double-freezing of the prostate in patients with prostatic cancer

In these studies, 10 patients with a confirmed histological diagnosis of stage C and D carcinoma underwent double-freezing of the prostate. The clinical courses in the first group (five patients) were favorable. In the second group (two patients), death by cachexia occurred due to the cancer. In the third group (three patients), death 4 weeks after the second cryosurgery suggests the effects of cryoshock. In the first and second groups, the results of the immunological examinations after the second freezing did not attain the predicted levels. Comparing the results of the third group with those of the first and second groups the primary differences was that the percentages of gamma-globulins and IgE were higher in the third group preoperatively. These findings suggest that patients with high percentages of gamma-globulin and high IgE levels are contraindicated for cryosurgery of the prostate.     

Extracellular alpha 6 integrin cleavage by urokinase-type plasminogen activator in human prostate cancer

During human prostate cancer progression, the integrin alpha6beta1 (laminin receptor) is expressed on the cancer cell surface during invasion and in lymph node metastases. We previously identified a novel structural variant of the alpha6 integrin called alpha6p. This variant was produced on the cell surface and was missing the beta-barrel extracellular domain. Using several different concentrations of amiloride, aminobenzamidine and PAI-1 and the urokinase-type plasminogen activator (uPA) function-blocking antibody (3689), we showed that uPA, acting as a protease, is responsible for production of alpha6p. We also showed that addition of uPA in the culture media of cells that do not produce alpha6p, resulted in a dose-dependent alpha6p production. In contrast, the addition of uPA did not result in the cleavage of other integrins. Using alpha2-antiplasmin and plasmin depleted media, we observed that uPA cleaves the alpha6 integrin directly. Further, 12-o-tetradecanoyl-phorbol-13-acetate (TPA) induced the production of alpha6p, and this induction was abolished by PAI-1 but not alpha2-antiplasmin. Finally, the alpha6p integrin variant was detected in invasive human prostate carcinoma tissue indicating that this is not a tissue culture phenomenon. These data, taken together, suggest that this is a novel function of uPA, that is, to remove the beta-barrel ligand-binding domain of the integrin while preserving its heterodimer association.     

Factors influencing the survival of patients with cancer of the prostate.

During the period 1969 through 1973, 777 new cases of cancer of the prostate in northern Alberta men were registered with the Alberta Cancer Registry. The overall survival rate after 5 years was 41.2%. As expected, the rates were higher for those aged less than 65 years than for those who were older at the time of diagnosis and higher for those without metastases than for those with metastases at that time. Urban residents had a higher survival rate than rural residents (45.3% v. 38.0%), and the survival ratio of the former, 1.31, was significant. Information on occupation, smoking and the interval between appearance of the first symptom and diagnosis was not always available. However, the differentials observed suggest that those in a professional occupation and nonsmokers live longer after the diagnosis of cancer of the prostate but that the interval before diagnosis does not affect the length of survival.     

Metabolic profile in patients with benign prostate hyperplasia or prostate cancer and normal glucose tolerance.

Familial predisposition together with several environmental factors may be involved in the pathogenesis of common prostate disease such as benign hypertrophy or prostate neoplasm. A higher incidence of both these conditions has been described in some insulin-resistant states such as obesity, but not much information is available on the effect of metabolic profile on gland morphology. The aim of this study was to evaluate the relation between glucose and lipid pattern and prostate diameters in two groups of non-diabetic individuals with benign prostate hypertrophy or cancer. 109 patients were recruited; plasma glucose, lipids and hormonal profile as well as an ultrasonographic evaluation of the gland volume and diameters were determined. Patients with prostate cancer had significantly higher levels of insulin and were more insulin resistant; in contrast, in subjects with prostate hypertrophy, fasting plasma glucose and--to a lesser extent--serum triglycerides emerged as the main determinants of gland volume. These observations may indicate that an improvement of insulin sensitivity and strategies to maintain a strict glucose and lipid control even in non-diabetic subjects are useful objectives in the prevention of prostate diseases.     

Lymphoprostatic scintigraphy in regional lymphatic mapping in patients with prostate cancer

The purpose of the investigation was to upgrade the diagnosis quality for metastatic lesion to the regional lymp nodes in prostate cancer. The results of the most widely used diagnostic techniques (computed tomography (CT), magnetic resonance Imaging, (MRI), radionuclide studies (RNS), and ultrasonography (USG)), which had been compared with those of histology of removed lymph nodes, were assessed. For this, 74 patients with prostate cancer were comprehensively examined and treated at the Central Research X-ray Radiolological Institute. The comparative assessment of radiodiagnostic techniques (USG, CT, MRI, and RNS) showed the high informative value of retroperitoneal lymph nodal MRI in the detection of structural-and-morphological and anatomic-and-topographic changes in the lymph nodes (87.5% sensitivity, 83.3% specificity, and 85.7% accuracy). The developed lymphoprostatic scintigraphy (LPSG) is an informative technique that allows the better diagnosis of prostate metastases to the regional lymph nodes (92.4% sensitivity, 91.7% specificity, and 92.1% accuracy; the prognostic value of a positive result is 90.7%). LPSG is superior in its informative value to small pelvic USG and CT and inferior to indirect lymphoscintigraphy and yields valuable additional information on the physiological function of the small pelvic lymphatic collector.     

Metabolite profiling of blood plasma of patients with prostate cancer

Prostate cancer is one of the most common types of cancer in men. It is though extremely important to search for specific markers including metabolites, which concentration in blood could be a diagnostic measure. In this regard, the metabolite profiling of blood plasma was performed with two groups of people: healthy volunteers (n = 30) and patients with prostate cancer, second stage (n = 40). The profiling protocol included proteins removal from blood plasma with methanol and direct analysis of metabolite fractions by mass spectrometry. Identification of the most abundant metabolites in samples was performed using an accurate mass tag and an isotope pattern methods. Cancer-specific metabolites were revealed by statistical analysis of metabolite intensities in the mass spectra. Six different metabolites were found to be cancer-specific. Two metabolites, acylcarnitine and arachidonoyl amine, have the AUC 0.97 and 0.86, respectively, which are higher than those from PSA test, 0.59.     

Displacements of fiducial markers in patients with prostate cancer treated with image guided radiotherapy: A single-institution descriptive study

Aim

To describe daily displacements when using fiducial markers as surrogates for the target volume in patients with prostate cancer treated with IGRT.

Background

The higher grade of conformity achieved with the use of modern radiation technologies in prostate cancer can increase the risk of geographical miss; therefore, an associated protocol of IGRT is recommended.

Materials and methods

A single-institution, retrospective, consecutive study was designed. 128 prostate cancer patients treated with daily on-line IGRT based on 2D kV orthogonal images were included. Daily displacement of the fiducial markers was considered as the difference between the position of the patient when using skin tattoos and the position after being relocated using fiducial markers. Measures of central tendency and dispersion were used to describe fiducial displacements.

Results

The implant itself took a mean time of 15 min. We did not detect any complications derived from the implant. 4296 sets of orthogonal images were identified, 128 sets of images corresponding to treatment initiation were excluded; 91 (2.1%) sets of images were excluded from the analysis after having identified that these images contained extreme outlier values. If IGRT had not been performed 25%, 10% or 5% of the treatments would have had displacements superior to 4, 7 or 9 mm respectively in any axis.

Conclusions

Image guidance is required when using highly conformal techniques; otherwise, at least 10% of daily treatments could have significant displacements. IGRT based on fiducial markers, with 2D kV orthogonal images is a convenient and fast method for performing image guidance.     

Metabolic fingerprinting of blood plasma from patients with prostate cancer

Application of blood plasma metabolites fingerprinting for the diagnostic of the 2nd stage of prostate cancer has been investigated. The diagnostic sensitivity (95%), specificity (96.7%) and accuracy (95.7%) of the metabolic fingerprinting were much higher then those for the ELISA PSA test (35%, 83.3% and 51.7%, respectively) performed for the same patients. Area under the ROC curve (0.994) suggests that the proposed approach based on the metabolic fingerprinting is effective and applicable in clinical practice.     

RNA interference-directed knockdown of urokinase plasminogen activator and urokinase plasminogen activator receptor inhibits prostate cancer cell invasion, survival, and tumorigenicity in vivo

The invasive ability of tumor cells plays a key role in prostate cancer metastasis and is a major cause of treatment failure. Urokinase plasminogen activator-(uPA) and its receptor (uPAR)-mediated signaling have been implicated in tumor cell invasion, survival, and metastasis in a variety of cancers. This study was undertaken to investigate the biological roles of uPA and uPAR in prostate cancer cell invasion and survival, and the potential of uPA and uPAR as targets for prostate cancer therapy. uPA and uPAR expression correlates with the metastatic potential of prostate cancer cells. Thus, therapies designed to inhibit uPA and uPAR expression would be beneficial. LNCaP, DU145, and PC3 are prostate cancer cell lines with low, moderate, and high metastatic potential, respectively, as demonstrated by their capacity to invade the extracellular matrix. In this study we utilized small hairpin RNAs (shRNAs), also referred to as small interfering RNAs, to target human uPA and uPAR. These small interfering RNA constructs significantly inhibited uPA and uPAR expression at both the mRNA and protein levels in the highly metastatic prostate cancer cell line PC3. Our data demonstrated that uPA-uPAR knockdown in PC3 cells resulted in a dramatic reduction of tumor cell invasion as indicated by a Matrigel invasion assay. Furthermore, simultaneous silencing of the genes for uPA and uPAR using a single plasmid construct expressing shRNAs for both uPA and uPAR significantly reduced cell viability and ultimately resulted in the induction of apoptotic cell death. RNA interference for uPA and uPAR also abrogated uPA-uPAR signaling to downstream target molecules such as ERK1/2 and Stat 3. In addition, our results demonstrated that intratumoral injection with the plasmid construct expressing shRNAs for uPA and uPAR almost completely inhibited established tumor growth and survival in an orthotopic mouse prostate cancer model. These findings uncovered evidence of a complex signaling network operating downstream of uPA-uPAR that actively advances tumor cell invasion, proliferation, and survival of prostate cancer cells. Thus, RNA interference-directed targeting of uPA and uPAR is a convenient and novel tool for studying the biological role of the uPA-uPAR system and raises the potential of its application for prostate cancer therapy.     

Current status of androgen suppression and radiotherapy for patients with prostate cancer

Analogous to the impact of anti-estrogen therapy in breast cancer, anti-androgen therapy may have a greater impact on the castrate male with non-metastatic disease. The use of castration or a LHRH drug alone, does not appear to adequately suppress intra-prostatic DHT (Dihydrotestosterone) levels. Normal prostate elements appear to be more efficient than metastatic elements at converting DHT precursors to active DHT. Thus, blocking this step may be more critical for clinically localized disease. Laverdiere et al. reported a 2 year positive (+) biopsy rate of 65% with XRT alone compared to 28% when 3 months of NHT preceded radiotherapy, but 5% if NHT was continued for a total of 10.5 months of combined androgen blockade (CAB). Bolla et al. incorporated one month of NHT prior to XRT followed by 3 years of an LHRH drug. An improvement in local control, disease free survival and overall survival of nearly 20% was noted at 5 years. Thus far, these important studies demonstrate that a survival benefit may require long term adjuvant hormonal therapy. There is a need for further studies to define the optimal timing and duration of CAB and the role of XRT. Long term data recently provided by the Radiation Therapy Oncology Group (RTOG) may provide insights into criteria for defining which patients are likely to benefit the most from long term CAB.     

Equivocal test results and prognostic staging uncertainties in the evaluation of patients with cancer of the prostate

In the staging of cancer, equivocal test results may occur in subjectively evaluated imaging procedures whose interpretations raise the possibility of metastases but are too uncertain to rule in or rule out metastatic spread, and in tests whose repetitions in the same patient yield conflicting results about dissemination. We assessed the frequency and prognostic correlates of test results giving equivocal evidence of disseminated (Stage IV) disease in an inception cohort of 280 patients receiving initial treatment for prostatic cancer between 1973-76. Among tests used for clinical staging, lymphangiograms (equivocal in 28 percent of tested patients), bone scans (equivocal in 25 percent of tested patients), and bone radiographs (equivocal in 20 percent of tested patients) most frequently yielded interpretations that equivocally suggested metastatic spread. Eighty-three (45 percent) of the 185 patients without clear-cut dissemination (Stages I-III) had at least one equivocal test result that suggested dissemination and that remained unresolved at the time of selection of therapy. Five-year survival (30 percent) for the 20 patients with local extracapsular spread (Stage III) and multiple equivocal results suggesting dissemination was identical to that for patients with clear-cut dissemination. In contrast, other patients with equivocal dissemination in Stages I-III had survival rates similar to those patients in the same stage and lacking equivocal dissemination. Unresolved equivocal staging results frequently complicate management decisions for patients with prostatic cancer. Survival analyses aid these decisions by demonstrating that equivocal findings of dissemination are prognostically unimportant unless they are multiple and occur in the context of unequivocal extracapsular spread.