Low-temperature plasma treatment induces DNA damage leading to necrotic cell death in primary prostate epithelial cells.

BACKGROUND: In recent years, the rapidly advancing field of low-temperature atmospheric pressure plasmas has shown considerable promise for future translational biomedical applications, including cancer therapy, through the generation of reactive oxygen and nitrogen species. METHOD: The cytopathic effect of low-temperature plasma was first verified in two commonly used prostate cell lines: BPH-1 and PC-3 cells. The study was then extended to analyse the effects in paired normal and tumour (Gleason grade 7) prostate epithelial cells cultured directly from patient tissue. Hydrogen peroxide (H2O2) and staurosporine were used as controls throughout. RESULTS: Low-temperature plasma (LTP) exposure resulted in high levels of DNA damage, a reduction in cell viability, and colony-forming ability. H2O2 formed in the culture medium was a likely facilitator of these effects. Necrosis and autophagy were recorded in primary cells, whereas cell lines exhibited apoptosis and necrosis. CONCLUSIONS: This study demonstrates that LTP treatment causes cytotoxic insult in primary prostate cells, leading to rapid necrotic cell death. It also highlights the need to study primary cultures in order to gain more realistic insight into patient response.

DNA hypermethylation in prostate cancer is a consequence of aberrant epithelial differentiation and hyperproliferation.

Prostate cancer (CaP) is mostly composed of luminal-like differentiated cells, but contains a small subpopulation of basal cells (including stem-like cells), which can proliferate and differentiate into luminal-like cells. In cancers, CpG island hypermethylation has been associated with gene downregulation, but the causal relationship between the two phenomena is still debated. Here we clarify the origin and function of CpG island hypermethylation in CaP, in the context of a cancer cell hierarchy and epithelial differentiation, by analysis of separated basal and luminal cells from cancers. For a set of genes (including GSTP1) that are hypermethylated in CaP, gene downregulation is the result of cell differentiation and is not cancer specific. Hypermethylation is however seen in more differentiated cancer cells and is promoted by hyperproliferation. These genes are maintained as actively expressed and methylation-free in undifferentiated CaP cells, and their hypermethylation is not essential for either tumour development or expansion. We present evidence for the causes and the dynamics of CpG island hypermethylation in CaP, showing that, for a specific set of genes, promoter methylation is downstream of gene downregulation and is not a driver of gene repression, while gene repression is a result of tissue-specific differentiation.

HDAC inhibitor confers radiosensitivity to prostate stem-like cells.

BACKGROUND: Radiotherapy can be an effective treatment for prostate cancer, but radiorecurrent tumours do develop. Considering prostate cancer heterogeneity, we hypothesised that primitive stem-like cells may constitute the radiation-resistant fraction. METHODS: Primary cultures were derived from patients undergoing resection for prostate cancer or benign prostatic hyperplasia. After short-term culture, three populations of cells were sorted, reflecting the prostate epithelial hierarchy, namely stem-like cells (SCs, α2ß1integrin(hi)/CD133(+)), transit-amplifying (TA, α2ß1integrin(hi)/CD133(-)) and committed basal (CB, α2ß1integrin(lo)) cells. Radiosensitivity was measured by colony-forming efficiency (CFE) and DNA damage by comet assay and DNA damage foci quantification. Immunofluorescence and flow cytometry were used to measure heterochromatin. The HDAC (histone deacetylase) inhibitor Trichostatin A was used as a radiosensitiser. RESULTS: Stem-like cells had increased CFE post irradiation compared with the more differentiated cells (TA and CB). The SC population sustained fewer lethal double-strand breaks than either TA or CB cells, which correlated with SCs being less proliferative and having increased levels of heterochromatin. Finally, treatment with an HDAC inhibitor sensitised the SCs to radiation. INTERPRETATION: Prostate SCs are more radioresistant than more differentiated cell populations. We suggest that the primitive cells survive radiation therapy and that pre-treatment with HDAC inhibitors may sensitise this resistant fraction.

Retinoic acid represses invasion and stem cell phenotype by induction of the metastasis suppressors RARRES1 and LXN.

The mouse haematopoietic stem cell (SC) regulator Latexin (LXN) is the only known homologue of the retinoic acid receptor responder 1 (RARRES1) gene. Both genes lie adjacent on chromosome 3 and differ mostly by the presence of a transmembrane domain in RARRES1. Despite their homology, it is not known whether they possess similar regulatory mechanisms, cellular localization and function. Here, we identified RARRES1 and LXN as highly significantly downregulated genes in human prostate SCs, whose expression was induced by the pro-differentiation agent all-trans retinoic acid (atRA). AtRA induced expression in the most differentiated cells compared with the SC fraction, suggesting that this subpopulation was less responsive to atRA. Small interfering RNA suppression of RARRES1 and LXN enhanced the SC properties of primary prostate cultures, as shown by a significant increase in their colony-forming ability. Expression of both RARRES1 and LXN was co-ordinately repressed by DNA methylation in prostate cancer cell lines and inhibition of RARRES1 and LXN increased the invasive capacity of primary prostate cultures, which also fully rescued an inhibitory effect induced by atRA. Moreover, we showed that RARRES1 and LXN reside within different sub-cellular compartments, providing evidence that RARRES1 is not a plasma membrane protein as previously supposed but is located primarily in the endoplasmic reticulum; whereas LXN was detected in the nucleus of prostate epithelial cells. Thus, LXN and RARRES1 are potential tumour suppressor genes, which are co-ordinately regulated, SC-silenced genes functioning to suppress invasion and colony-forming ability of prostate cancer cells; yet the proteins reside within different sub-cellular compartments.

Management of the gastrointestinal tract at the time of cystectomy.

Radical cystectomy impacts on the gastro-intestinal tract in several ways. Clearly there is the need for bowel mobilisation, resection and anastamosis in order to create a urinary diversion, and the use of bowel preparation or antibiotics are controversial topics. Post-operatively ileus is common and there is debate about the routine use of NG tubes. Early enteral feeding is a modern concept but not yet proven. In the long-term there can be problems such as diarrhoea and B12 deficiency. All of these issues are discussed in this review using the latest available evidence.

Well leg compartment syndrome after pelvic and perineal surgery in the lithotomy position.

OBJECTIVE: Lower limb compartment syndrome after prolonged surgical procedures performed in the lithotomy position is a rare but potentially devastating complication. It is recognised after urological, colorectal, and gynaecological procedures. Sixteen cases of compartment syndrome after urological surgery have been reported. The objective of this study was to estimate the incidence of this complication in urological practice and identify risk factors for its development. DESIGN: A postal survey of UK consultant urologists was conducted. RESULTS: Replies were received from 261 consultants. In total there were 65 cases of compartment syndrome. Compartment syndrome occurred after radical cystectomy and urinary diversion in 51 cases and was rare in procedures lasting less than four hours. The incidence of compartment syndrome after cystectomy was estimated at around 1 in 500 cases. Risk factors for its development included perioperative blood loss, peripheral vascular disease, and obesity. CONCLUSIONS: Compartment syndrome after use of the lithotomy position may be more common than is generally appreciated and has been underreported in the past. All staff should be aware of this serious complication and adopt strategies for its avoidance.

The management of lymph node metastasis from bladder cancer.

AIM: The presence of pelvic lymph node metastasis from bladder cancer has traditionally been associated with a very poor prognosis. The aim of this paper is to review the literature with regard to the management of patients with nodal disease, particularly gross nodal metastasis and suggest a strategy for management of these patients. METHODS: We performed a literature search in the PubMed database and the reference lists of relevant papers describing the management of locally advanced bladder cancer. FINDINGS: There are no randomised studies relating specifically to the management of nodal metastasis in bladder cancer. It is clear however that a significant number of patients with micrometastatic nodal disease may be cured. Few studies exist which address the management of patients with gross nodal disease and consist of series from a limited number of institutions. In patients with gross nodal disease detected pre-operatively or at the time of surgery, a multimodality approach consisting of surgery, chemotherapy and possibly radiotherapy seems appropriate. The prognosis of such patients relates to the pathological stage of the primary tumour and the degree of lymph node involvement. In addition a good response to neoadjuvant chemotherapy may identify patients who are likely to survive longer. CONCLUSIONS: The prognosis for patients with gross nodal disease from bladder cancer is poor although cure may be possible in a small number of patients. In such cases a multimodality approach is appropriate and management decisions should be made on an individual patient basis.

A vaccination strategy for the long-term suppression of androgens in advanced prostate cancer.

OBJECTIVES: We have previously reported the ability of D17DT (formerly GnRH-DT) vaccination to produce castrate levels of androgens in men with advanced prostate cancer. This study examines the efficacy and tolerability of 3 and 15 micrograms of D17DT in 12 patients with advanced prostate cancer to establish a dose-response relationship. METHODS: 12 patients received either 3 or 15 micrograms of D17DT as 3 deep intramuscular injections over 6 weeks. Outcome was assessed in terms of physical and biochemical evaluations of clinical progression and antibody titres. RESULTS: Significant titres of anti-GnRH antibodies were detected in 2 out of 6 subjects who received 15 micrograms of D17DT; suppression of testosterone to castrate levels accompanied by a significant and prolonged reduction in PSA was also demonstrated. No responses were seen following treatment with 3 micrograms of D17DT. CONCLUSION: The induction of anti-GnRH antibodies through vaccination with 15 micrograms D17DT can produce and sustain castrate levels of testosterone in men with advanced prostate cancer.

Production and characterization of 188Re-C595 antibody for radioimmunotherapy of transitional cell bladder cancer.

UNLABELLED: Bladder cancer was responsible for >12,000 deaths in the United States in 1999. The high-molecular-weight glycoprotein MUC1 mucin is overexpressed on bladder tumors and represents a useful target for radioimmunoscintigraphy and radioimmunotherapy. We report on the production and initial tracer studies of a 188Re-antibody complex directed against this target and intended for intravesical radioimmunotherapy of superficial bladder cancer. METHODS: 188Re perrhenate was eluted from a 188W/188Re generator. C595 antibody was reduced with 2-mercaptoethanol and was labeled in the presence of stannous tartrate. The final reaction mixture contained high-molecular-weight contamination, which was removed from the complex using an affinity separation technique. The specificity and integrity of the antibody complex were tested by radioimmunoassay and size exclusion chromatography. Tumor localization was investigated using an ex vivo model in human cystectomy specimens. Tracer amounts of the complex were also administered intravesically to three patients with bladder cancer, who were then imaged by gamma scintigraphy. RESULTS: The complex was immunoreactive (70% +/- 17%) and specific for MUC1 antigens. A peak corresponding to a protein of 150 kDa was observed on size exclusion chromatography, showing that the complex was homogeneous. Binding to bladder tumors was observed in an ex vivo model in which tumors were successfully imaged in four specimens. The mean tumor-to-normal tissue ratio in ex vivo bladders was 7:1. Tumor uptake after intravesical administration was confirmed in three patients with bladder cancer (mean tumor-to-normal tissue ratio, 4:1). CONCLUSION: The C595 antibody was labeled with 188Re, providing a radioimmunoconjugate with high immunoreactivity and specificity. Its ability to localize in tumors both in an ex vivo model and after intravesical administration to patients has been shown. This approach will now be extended for the therapy of superficial bladder cancer.

Production and characterisation of a C595 antibody-99mTc conjugate for immunoscintigraphy of bladder cancer.

Current radiological techniques for staging bladder cancer are inaccurate, especially in the identification of pelvic lymph node metastases. Immunoscintigraphy has the potential to offer improved staging for bladder cancer. The aim of this study was to label the anti-MUC1 monoclonal antibody C595 with 99mtechnetium (Tc), the most widely used diagnostic radionuclide, and assess the potential of the resultant conjugate for intravenous immunoscintigraphy of bladder cancer. A direct, reduction-mediated technique was used to label the antibody. The resultant conjugate was shown to be highly immunoreactive, stable and bound specifically to MUC1. The ability of the conjugate to bind to bladder tumours was demonstrated in an ex vivo model where the mean tumour:normal urothelial uptake was 5.7:1 and by intravesical administration in patients with bladder cancer where the mean tumour:normal urothelial uptake was 20.4:1. The ability of the conjugate to localise MUC1-expressing tumours was demonstrated in a nude mouse xenograft model. A conjugate of 99mTc-C595 has been produced and characterised, and it may be suitable for intravenous immunoscintigraphy, a potential novel staging tool for bladder cancer.

99mTechnetium-C595 radioimmunoscintigraphy: a potential staging tool for bladder cancer.

OBJECTIVES: To assess whether immunoscintigraphy using a conjugate of the anti-MUC1 monoclonal antibody C595 and 99mTc could be used to target transitional cell bladder cancer after intravenous administration to patients. PATIENTS AND METHODS: Twenty-one patients with invasive or metastatic transitional cell carcinoma were recruited. Patients received 1 mg of C595 labelled with 800 MBq 99mTc followed by imaging at 0.5, 6 and 24 h using a combination of planar and single-photon emission computed tomography. Of these patients, 14 subsequently underwent cystectomy, four underwent radiotherapy and the remaining three had histologically confirmed metastatic disease. The results of immunoscintigraphy were compared with surgical findings and conventional radiology. RESULTS: There were no adverse reactions in any patient. Of the 20 patients who were found to have tumour at the time of the study, positive localization of antibody in tumour was apparent in 16. Of the remaining four patients, false-positive localization of antibody in presumed nodal tissue was detected in two. The remaining scan results were equivocal. In three patients, histologically confirmed pelvic nodal metastases that had not been detected on preoperative computed tomography were identified. CONCLUSION: These early results show the potential of 99mTc-C595 immunoscintigraphy for staging bladder cancer. A larger study is needed to fully evaluate the technique.

Anti-GnRH antibodies can induce castrate levels of testosterone in patients with advanced prostate cancer.

D17DT consists of the GnRH decapeptide linked to diphtheria toxoid. The aim of this pilot study was to assess the tolerance of D17DT and the production of anti-GnRH antibodies from two doses, 30 and 100 microg, in patients with locally advanced prostate cancer. Twelve patients with histologically proven prostate cancer in whom hormonal therapy was indicated were recruited. Patients received either 30 or 100 microg given intramuscularly on three separate occasions over six weeks. Patients were followed up and blood was taken for estimation of serum testosterone, PSA and anti-GnRH antibody titre. Overall the drug was well tolerated. In 5 patients a significant reduction in serum testosterone and PSA was seen. Castrate levels of testosterone were achieved in 4 and maintained for up to 9 months. Patients with the highest antibody titre had the best response in terms of testosterone suppression. This study shows that it is possible to immunize a patient with prostate cancer against GnRH to induce castrate levels of testosterone. This state appears to be reversible. This novel form of immunotherapy may have advantages over conventional forms of hormonal therapy and further studies are warranted in order to try and increase the proportion of responders.

MUC1 mucin as a tumour marker in bladder cancer.

OBJECTIVE: To evaluate serum MUC1 levels (a high molecular weight glycoprotein which is upregulated and abnormally glycosylated in bladder cancer and other carcinomas) in patients with a variety of stages and grades of transitional cell carcinoma (TCC) of the bladder, to assess its potential as a tumour marker. PATIENTS AND METHODS: Blood samples were taken before treatment in 87 patients with TCC of the bladder and in 31 controls undergoing cystoscopy for benign conditions. Serum MUC1 levels were estimated with an enzyme-linked immunosorbent assay using the C595 monoclonal antibody. RESULTS: Of patients with T4 tumours, 47% had MUC1 levels above the normal range (P<0.001); patients with T3 tumours also had significantly higher MUC1 levels than controls. The overall sensitivity was only 24% for all tumours when the upper limit of normal was defined as 4.8 U/mL; the specificity was 97%. CONCLUSION: Serum MUC1 is not as useful tumour marker for screening, as it has a low sensitivity. However, MUC1 levels are high in advanced disease and serum MUC1 levels may be useful for disease monitoring.