Predictive Models for Acute Oral Systemic Toxicity: A Workshop to Bridge the Gap from Research to Regulation

In early 2018, the Interagency Coordinating Committee for the Validation of Alternative Methods (ICCVAM) published the "Strategic Roadmap for Establishing New Approaches to Evaluate the Safety of Chemicals and Medical Products in the United States" (ICCVAM 2018). Cross-agency federal workgroups have been established to implement this roadmap for various toxicological testing endpoints, with an initial focus on acute toxicity testing. The ICCVAM acute toxicity workgroup (ATWG) helped organize a global collaboration to build predictive in silico models for acute oral systemic toxicity, based on a large dataset of rodent studies and targeted towards regulatory needs identified across federal agencies. Thirty-two international groups across government, industry, and academia participated in the project, culminating in a workshop in April 2018 held at the National Institutes of Health (NIH). At the workshop, computational modelers and regulatory decision makers met to discuss the feasibility of using predictive model outputs for regulatory use in lieu of acute oral systemic toxicity testing. The models were combined to yield consensus predictions which demonstrated excellent performance when compared to the animal data, and workshop outcomes and follow-up activities to make these tools available and put them into practice are discussed here.

An evaluation of selected (Q)SARs/expert systems for predicting skin sensitisation potential

Predictive testing to characterise substances for their skin sensitisation potential has historically been based on animal models such as the Local Lymph Node Assay (LLNA) and the Guinea Pig Maximisation Test (GPMT). In recent years, EU regulations, have provided a strong incentive to develop non-animal alternatives, such as expert systems software. Here we selected three different types of expert systems: VEGA (statistical), Derek Nexus (knowledge-based) and TIMES-SS (hybrid), and evaluated their performance using two large sets of animal data: one set of 1249 substances from eChemportal and a second set of 515 substances from NICEATM. A model was considered successful at predicting skin sensitisation potential if it had at least the same balanced accuracy as the LLNA and the GPMT had in predicting the other outcomes, which ranged from 79% to 86%. We found that the highest balanced accuracy of any of the expert systems evaluated was 65% when making global predictions. For substances within the domain of TIMES-SS, however, balanced accuracies for the two datasets were found to be 79% and 82%. In those cases where a chemical was within the TIMES-SS domain, the TIMES-SS skin sensitisation hazard prediction had the same confidence as the result from LLNA or GPMT.

Application of IATA - A case study in evaluating the global and local performance of a Bayesian network model for skin sensitization

The information characterizing key events in an Adverse Outcome Pathway (AOP) can be generated from in silico, in chemico, in vitro and in vivo approaches. Integration of this information and interpretation for decision making are known as integrated approaches to testing and assessment (IATA). One such IATA was published by Jaworska et al., which describes a Bayesian network model known as ITS-2. The current work evaluated the performance of ITS-2 using a stratified cross-validation approach. We also characterized the impact of replacing the most significant component of the network, output from the expert system TIMES-SS, with structural alert information from the OECD Toolbox and Toxtree. Lack of structural alerts or TIMES-SS predictions yielded a sensitization potential prediction of 79%. If the TIMES-SS prediction was replaced by a structural alert indicator, the network predictivity increased up to 87%. The original network's predictivity was 89%. The local applicability domain of the original ITS-2 network was also evaluated using reaction mechanistic domains to understand what types of chemicals ITS-2 was able to make the best predictions for. We found that the original network was successful at predicting which chemicals would be sensitizers, but not at predicting their potency.

The prognostic utility of the transcription factor SRF in docetaxel-resistant prostate cancer: in-vitro discovery and in-vivo validation

Background

Docetaxel based therapy is one of the first line chemotherapeutic agents for the treatment of metastatic castrate-resistant prostate cancer. However, one of the major obstacles in the treatment of these patients is docetaxel-resistance. Defining the mechanisms of resistance so as to inform subsequent treatment options and combinations represents a challenge for clinicians and scientists.

Previous work by our group has shown complex changes in pro and anti-apoptotic proteins in the development of resistance to docetaxel. Targeting these changes individually does not significantly impact on the resistant phenotype but understanding the central signalling pathways and transcription factors (TFs) which control these could represent a more appropriate therapeutic targeting approach.

Methods

Using a number of docetaxel-resistant sublines of PC-3 cells, we have undertaken a transcriptomic analysis by expression microarray using the Affymetrix Human Gene 1.0 ST Array and in conjunction with bioinformatic analyses undertook to predict dysregulated TFs in docetaxel resistant prostate cancer. The clinical significance of this prediction was ascertained by performing immunohistochemical (IHC) analysis of an identified TF (SRF) in the metastatic sites from men who died of advanced CRPC. Investigation of the functional role of SRF was examined by manipulating SRF using SiRNA in a docetaxel-resistant PC-3 cell line model.

Results

The transcription factors identified include serum response factor (SRF), nuclear factor kappa-B (NFκB), heat shock factor protein 1 (HSF1), testicular receptor 2 & 4 (TR2 &4), vitamin-D and retinoid x receptor (VDR-RXR) and oestrogen-receptor 1 (ESR1), which are predicted to be responsible for the differential gene expression observed in docetaxel-resistance. IHC analysis to quantify nuclear expression of the identified TF SRF correlates with both survival from date of bone metastasis (p = 0.003), survival from androgen independence (p = 0.00002), and overall survival from prostate cancer (p = 0.0044). Functional knockdown of SRF by siRNA demonstrated a reversal of apoptotic resistance to docetaxel treatment in the docetaxel-resistant PC-3 cell line model.

Conclusions

Our results suggest that SRF could aid in treatment stratification of prostate cancer, and may also represent a therapeutic target in the treatment of men afflicted with advanced prostate cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3100-4) contains supplementary material, which is available to authorized users.

Is skin penetration a determining factor in skin sensitization potential and potency? Refuting the notion of a LogKow threshold for skin sensitization

It is widely accepted that substances that cannot penetrate through the skin will not be sensitizers. LogKow and molecular weight (MW) have been used to set thresholds for sensitization potential. Highly hydrophilic substances e.g. LogKow ≤ 1 are expected not to penetrate effectively to induce sensitization. To investigate whether LogKow >1 is a true requirement for sensitization, a large dataset of substances that had been evaluated for their skin sensitization potential under Registration, Evaluation, Authorisation and restriction of CHemicals (REACH), together with available measured LogKow values was compiled using the OECD eChemPortal. The incidence of sensitizers relative to non-sensitizers above and below a LogKow of 1 was explored. Reaction chemistry principles were used to explain the sensitization observed for the subset of substances with a LogKow ≤0. 1482 substances were identified with skin sensitization data and measured LogKow values. 525 substances had a measured LogKow ≤ 1, 100 of those were sensitizers. There was no significant difference in the incidence of sensitizers above and below a LogKow of 1. Reaction chemistry principles that had been established for lower MW and more hydrophobic substances were found to be still valid in rationalizing the skin sensitizers with a LogKow ≤ 0. The LogKow threshold arises from the widespread misconception that the ability to efficiently penetrate the stratum corneum is a key determinant of sensitization potential and potency. Copyright © 2016 John Wiley & Sons, Ltd.

Current and Future Perspectives on the Development, Evaluation, and Application of in Silico Approaches for Predicting Toxicity

Exploiting non-testing approaches to predict toxicity early in the drug discovery development cycle is a helpful component in minimizing expensive drug failures due to toxicity being identified in late development or even during clinical trials. Changes in regulations in the industrial chemicals and cosmetics sectors in recent years have prompted a significant number of advances in the development, application, and assessment of non-testing approaches, such as (Q)SARs. Many efforts have also been undertaken to establish guiding principles for performing read-across within category and analogue approaches. This review offers a perspective, as taken from these sectors, of the current status of non-testing approaches, their evolution in light of the advances in high-throughput approaches and constructs such as adverse outcome pathways, and their potential relevance for drug discovery. It also proposes a workflow for how non-testing approaches could be practically integrated within testing and assessment strategies.

Gram-negative bacteraemia; a multi-centre prospective evaluation of empiric antibiotic therapy and outcome in English acute hospitals

Increasing antibiotic resistance makes choosing antibiotics for suspected Gram-negative infection challenging. This study set out to identify key determinants of mortality among patients with Gram-negative bacteraemia, focusing particularly on the importance of appropriate empiric antibiotic treatment. We conducted a prospective observational study of 679 unselected adults with Gram-negative bacteraemia at ten acute english hospitals between October 2013 and March 2014. Appropriate empiric antibiotic treatment was defined as intravenous treatment on the day of blood culture collection with an antibiotic to which the cultured organism was sensitive in vitro. Mortality analyses were adjusted for patient demographics, co-morbidities and illness severity. The majority of bacteraemias were community-onset (70%); most were caused by Escherichia coli (65%), Klebsiella spp. (15%) or Pseudomonas spp. (7%). Main foci of infection were urinary tract (51%), abdomen/biliary tract (20%) and lower respiratory tract (14%). The main antibiotics used were co-amoxiclav (32%) and piperacillin-tazobactam (30%) with 34% receiving combination therapy (predominantly aminoglycosides). Empiric treatment was inappropriate in 34%. All-cause mortality was 8% at 7 days and 15% at 30 days. Independent predictors of mortality (p <0.05) included older age, greater burden of co-morbid disease, severity of illness at presentation and inflammatory response. Inappropriate empiric antibiotic therapy was not associated with mortality at either time-point (adjusted OR 0.82; 95% CI 0.35-1.94 and adjusted OR 0.92; 95% CI 0.50-1.66, respectively). Although our study does not exclude an impact of empiric antibiotic choice on survival in Gram-negative bacteraemia, outcome is determined primarily by patient and disease factors.

Phosphorylation of ezrin-radixin-moesin-binding phosphoprotein 50 (EBP50) by Akt promotes stability and mitogenic function of S-phase kinase-associated protein-2 (Skp2)

The regulation of the cell cycle by the ubiquitin-proteasome system is dependent on the activity of E3 ligases. Skp2 (S-phase kinase associated protein-2) is the substrate recognition subunit of the E3 ligase that ubiquitylates the cell cycle inhibitors p21(cip1) and p27(kip1) thus promoting cell cycle progression. Increased expression of Skp2 is frequently observed in diseases characterized by excessive cell proliferation, such as cancer and neointima hyperplasia. The stability and cellular localization of Skp2 are regulated by Akt, but the molecular mechanisms underlying these effects remain only partly understood. The scaffolding protein Ezrin-Binding Phosphoprotein of 50 kDa (EBP50) contains two PDZ domains and plays a critical role in the development of neointimal hyperplasia. Here we report that EBP50 directly binds Skp2 via its first PDZ domain. Moreover, EBP50 is phosphorylated by Akt on Thr-156 within the second PDZ domain, an event that allosterically promotes binding to Skp2. The interaction with EBP50 causes cytoplasmic localization of Skp2, increases Skp2 stability and promotes proliferation of primary vascular smooth muscle cells. Collectively, these studies define a novel regulatory mechanism contributing to aberrant cell growth and highlight the importance of scaffolding function of EBP50 in Akt-dependent cell proliferation.

Small molecule inhibition of the Na(+)/H(+) exchange regulatory factor 1 and parathyroid hormone 1 receptor interaction

We have identified a series of small molecules that bind to the canonical peptide binding groove of the PDZ1 domain of NHERF1 and effectively compete with the association of the C-terminus of the parathyroid hormone 1 receptor (PTH1R). Employing nuclear magnetic resonance and molecular modeling, we characterize the mode of binding that involves the GYGF loop important for the association of the C-terminus of PTH1R. We demonstrate that the common core of the small molecules binds to the PDZ1 domain of NHERF1 and displaces a (15)N-labeled peptide corresponding to the C-terminus of PTH1R. The small size (molecular weight of 192) of this core scaffold makes it an excellent candidate for further elaboration in the development of an inhibitor for this important protein-protein interaction.

A study on the theoretical and practical accuracy of conoscopic holography-based surface measurements: toward image registration in minimally invasive surgery

BACKGROUND

Registered medical images can assist with surgical navigation and enable image-guided therapy delivery. In soft tissues, surface-based registration is often used and can be facilitated by laser surface scanning. Tracked conoscopic holography (which provides distance measurements) has been recently proposed as a minimally invasive way to obtain surface scans. Moving this technique from concept to clinical use requires a rigorous accuracy evaluation, which is the purpose of our paper.

METHODS

We adapt recent non-homogeneous and anisotropic point-based registration results to provide a theoretical framework for predicting the accuracy of tracked distance measurement systems. Experiments are conducted a complex objects of defined geometry, an anthropomorphic kidney phantom and a human cadaver kidney.

RESULTS

Experiments agree with model predictions, producing point RMS errors consistently < 1 mm, surface-based registration with mean closest point error < 1 mm in the phantom and a RMS target registration error of 0.8 mm in the human cadaver kidney.

CONCLUSIONS

Tracked conoscopic holography is clinically viable; it enables minimally invasive surface scan accuracy comparable to current clinical methods that require open surgery.

Detecting soluble clusterin in in-vitro and in-vivo models of prostate cancer

PSA, the only relevant marker for prostate cancer, has a low predictive value; moreover its low threshold leads to unnecessary biopsies with associated complications. Identification of prognostic factors is an important goal in prostate cancer. In the search for new markers, clusterin, has some potential as it is closely linked with cancer progression and resistance to apoptosis. We looked at the expression of secreted clusterin (sCLU) in prostate cells to determine correlations with progression and drug resistance. The plasmatic expression of sCLU was also investigated in order to use it as a potential marker for prostate cancer. sCLU expression was studied using Western blotting on cultured prostate cells, PWR-1E, PC3 and PC3 Docetaxel resistant cells in the cytosol and culture medium. An inhouse ELISA test was developed to determine sCLU expression in culture media and plasma samples. A patient cohort was identified from the Prostate Cancer Research Consortium Bio-Resource and plasmatic expression of sCLU was studied using western blotting and the inhouse ELISA test. Only the fully processed form of sCLU was identified in the medium of cells with increased expression associated with increased progression of disease and resistance to docetaxel. Plasmatic expression of sCLU was significantly higher in the plasma of patients with high grade prostate cancer with extracapsular extension than in the plasma of prostate cancer patients without extracapsular extension. Plasmatic sCLU may be an effective prognostic marker of prostate cancer and needs to be tested in a multimarker approach.

The West Pacific diversity hotspot as a source or sink for new species? Population genetic insights from the Indo-Pacific parrotfish Scarus rubroviolaceus

We used a population genetic approach to quantify major population subdivisions and patterns of migration within a broadly distributed Indo-Pacific parrotfish. We genotyped 15 microsatellite loci in Scarus rubroviolaceus collected from 20 localities between Africa and the Americas. A STRUCTURE model indicates the presence of four major populations: Eastern Pacific, Hawaii, Central-West Pacific and a less well-differentiated Indian Ocean. We used the isolation and migration model to estimate splitting times, population sizes and migration patterns between sister population pairs. To eliminate loci under selection, we used BayeScan to select loci for three isolation and migration models: Eastern Pacific and Central-West Pacific, Hawaii and the Central-West Pacific, and Indian Ocean and the Central-West Pacific. To test the assumption of a stepwise mutation model (SMM), we used likelihood to test the SMM against a two-phase model that allowed mutational complexity. A posteriori, minor departures from SMM were estimated to affect ≤2% of the alleles in the data. The data were informative about the contemporary and ancestral population sizes, migration rates and the splitting time in the eastern Pacific/Central-West Pacific comparison. The model revealed a splitting time ∼17,000 BP, a larger contemporary N(e) in the Central-West Pacific than in the eastern Pacific and a strong bias of east to west migration. These characteristics support the Center of Accumulation model of peripatric diversification in low-diversity peripheral sites and perhaps migration from those sites to the western Pacific diversity hotspot.

The role of registration in accurate surgical guidance

Registration is presented as the central issue of surgical guidance. The focus is on the accuracy of approaches employed today, all of which use pre-operative images to guide surgery on rigid anatomy. The three most well-established approaches to guidance, namely the stereotactic frame, point fiducials, and surface matching, are examined in detail, together with two new approaches based on microstereotactic frames. It is shown that each method relies on the registration of points in the image to corresponding points in the operating room, and therefore that the error patterns associated with point registration are similar for all of them. Three types of registration error, namely fiducial localization error (FLE), fiducial registration error (FRE), and target registration error (TRE), are highlighted, as well as two additional guidance errors, namely target localization error and total targeting error, the latter of which is the overall error of the guidance system. Statistical relationships between TRE and FLE, between FRE and FLE, and between TRE, TLE, and TTE are given. Finally some myths concerning fiducial registration are highlighted.

A rare benign renal tumour presenting as polycythaemia in a teenage girl

We present the case of a 15-year-old girl who presented with polycythemia. CT abdomen revealed an enhancing mass in the upper pole of her left kidney with features suggestive of renal cell carcinoma. She underwent a laparoscopic radical nephrectomy. Histology demonstrated a well circumscribed, focally encapsulated, round blue cell tumour showing areas of microcalcifications and numerous psammoma bodies. Imunostaining showed diffuse positive staining for CD 57. This was consistent with a diagnosis of metanephric adenoma a rare benign epithelial renal tumour.

External validation of the 2007 and 2001 Partin tables in Irish prostate cancer patients

INTRODUCTION

External validation of predictive prostate cancer nomograms is of critical importance within distinct geographical locations, prior to their institution into routine clinical practice. We performed external validation of the 2007 and 2001 Partin tables in a cohort of Irish prostate cancer patients.

PATIENTS AND METHODS

Men enrolled in the Irish Prostate Cancer Research Consortium (n = 175) and who had undergone radical prostatectomy between 2004 and 2008 were used to externally validate the 2007 and 2001 Partin tables. A comparative analysis of the clinical and pathological parameters of the Irish and Partin patient cohorts was performed. The reported receiver operating characteristic (ROC) curve derived area under the curve (AUC) values were used to assess for variations in predictive accuracy. Statistical analyses were calculated with R software.

RESULTS

AUC values assigned to the differentiation of extra-prostatic extension and seminal vesicle invasion using the 2007 tables are 22 and 3%, respectively. The 2007 Partin tables showed superior accuracy for all parameters, excluding seminal vesicle invasion.

CONCLUSION

Cumulatively the Partin tables showed poor discriminate ability for prediction of post-radical prostatectomy pathological outcomes in Irish men, necessitating caution in their clinical utilisation.

Carbonic anhydrase IX expression in prostate cancer

Tumour hypoxia is associated with over 70% of solid tumours including prostate and colorectal cancer. Hypoxia promotes tumour progression and resistance to treatment. Carbonic anhydrase IX (CA IX) is an endogenous marker of hypoxia. It is expressed in lung and renal cell carcinomas and is associated with a poor prognosis. CA IX has an important role in maintaining pH levels in the highly metabolically active cancer cell. The expression of CA IX in prostate cancer has not previously been investigated. Immunohistochemistry was used to examine CA IX expression in 59 patients, using tissue microarrays (TMAs) and full sections of BPH, surrounding stroma and prostate adenocarcinoma. Cores reviewed included 189 BPH, 130 Gleason grade 3, 93 Gleason grade 4, 40 Gleason grade 5. CA IX expression in colorectal cancer and HIF 1alpha in prostate cancer acted as positive controls. There was only occasional cell staining for CA IX expression. Although prostate cancer is a hypoxic tumour it does not express CA IX. This implies it relies on alternative pathways for maintaining pH balance in cancer. These studies would indicate that CA IX is not a suitable marker of hypoxia in prostate cancer.

Should patients with symptomatic BPH have a trial of medical therapy by their general practitioner prior to referral for urological assessment?

The British Association of Urological Surgeons (BAUS) has recently recommended guidelines for the management of Lower Urinary Tract Sypmtoms by GPs outlining the indications for urological referral. We wished to assess the prescription of medical therapy by GPs in the referrals to our LUTS pre-assessment clinic. 115 consecutive patients were reviewed prospectively, over a three month period. Each patient was assessed for International Prostatic Symptom Score (IPSS) and Bother Score, uroflowometry with post void residual and whether medical therapy had been commenced (D-Blocker or 5-D-Reductase inhibitor). The majority of patients (75%) were classified with moderate symptoms. Only 10% of those with moderate symptoms and 5% of those with severe symptoms were commenced on medical therapy by their GP as recommended by the BAUS guidelines. Only 30 patients (26%) had completed an IPSS form with their GP. The majority of patients referred to our service for assessment of LUTS have at least moderate symptom severity and are not prescribed medical therapy by their GP. Further primary care education with greater emphasis on the BAUS LUTS algorithm prior to referral to an urologist should be encouraged.

Differential White Cell Count Relationships With Human Cardiac Allograft Rejection

The focus of research in allograft rejection has targeted the lymphocyte, with little attention given to the neutrophil. Recent data indicate that a perioperative neutrophil influx into the cardiac allograft influences early rejection. Factors that influence neutrophil transendothelial migration might offer predictive markers of rejection. We explored the relationship between the number of circulating neutrophils in heart transplant recipients and the development of rejection. Differential white cell counts were obtained prior to transplantation and concurrently with subsequent endomyocardial rejection surveillance biopsies for 53 heart transplant recipients undergoing 410 biopsies. Preoperative differential white cell counts had no relationship with rejection. In the first 3 months after transplantation, no relationship was found between contemporary differential white cell counts and rejection. However, more than 3 months following surgery, rejection grade positively correlated on univariate analysis with neutrophil counts and the usage of cyclosporine, prednisolone, and mycophenolate. There was no relationship with eosinophils or lymphocytes. Multivariate analysis demonstrated a persistent relationship among rejection severity, neutrophil count, and prednisolone usage. A significant positive association of higher steroid usage with higher rejection grades must reflect efforts to treat patients with rejection. The significant association of higher neutrophil counts with higher rejection severity might suggest a pathological contribution to rejection. However, given the neutrophilia response to acute steroid administration, we must conclude that the neutrophil association was related to steroid administration. The absence of a relationship between white cell counts and rejection suggests that functional rather than antiproliferative strategies may offer the greatest therapeutic potential.

Application of proteomic strategies to the identification of urinary biomarkers for prostate cancer: a review

In the post-genomic era, genes and proteins are now studied on a more comprehensive scale. Studying disease processes at only the genetic or transcriptomic level will give an incomplete amount of information. A proteomic approach potentially allows for a more global overview of how disease processes affect the proteins present in cells, tissues and organisms. The challenge arises in determining which proteins are affected in specific diseases and establishing which of these changes are unique to a particular disease. Existing and emerging proteomic technologies allow for high throughput analysis of proteins in a variety of sample types. Prostate cancer is a significant male health problem in the Western world. It is widely accepted that more specific prognostic and diagnostic markers of prostate cancer are urgently required. The present paper suggests that urine may be an attractive biofluid in which to pursue the identification of novel biomarkers of prostate cancer. This review introduces some proteomic techniques including mass spectrometry and the newer, quantitative proteomic strategies. It focuses on the potential application of these platforms to novel urinary biomarker identification in prostate malignancy. It also includes a synopsis of the current literature on urinary proteomics.

Expression and regulation of connective tissue growth factor by transforming growth factor beta and tumour necrosis factor alpha in fibroblasts isolated from strictures in patients with Crohn's disease

BACKGROUND

Connective tissue growth factor (CTGF) stimulates fibroblast proliferation and extracellular matrix production. Fibroblasts may initiate stricture formation in Crohn's disease through overexpression of CTGF. Stricturing that occurs in patients with Crohn's disease after treatment with anti-tumour necrosis factor (TNF) alpha may be due to dysregulation of CTGF homeostasis. The aim of this study was to examine CTGF expression and regulation in fibroblasts isolated from patients with Crohn's disease.

METHODS

Fibroblasts were isolated by a primary explant technique from serosal biopsies of strictured segments of bowel in eight patients undergoing resection for Crohn's disease and from normal colon in seven patients having resection for benign or malignant colorectal disease. Cells were stimulated with transforming growth factor (TGF) beta and TNF-alpha. CTGF protein and mRNA expression were measured by western blotting and real-time polymerase chain reaction respectively.

RESULTS

Mean(s.d.) CTGF protein expression in strictured Crohn's fibroblasts was higher than that in normal fibroblasts (56.5(9.7) versus 17.0(10.0) respectively; P = 0.011). In normal and strictured Crohn's fibroblasts, culture with TGF-beta increased CTGF protein and mRNA expression. Co-culture of normal fibroblasts with TNF-alpha suppressed TGF-beta-stimulated CTGF expression.

CONCLUSION

: Increased expression of CTGF in strictured Crohn's fibroblasts underlies its role in fibrosis. TNF-alpha suppresses fibrosis by downregulating fibroblast CTGF expression, an effect that may be lost following anti-TNF-alpha treatment, thereby promoting stricture formation.

Novel titanocene anti-cancer drugs and their effect on apoptosis and the apoptotic pathway in prostate cancer cells

Advanced prostate cancer is not curable by current treatment strategies indicating a significant need for new chemotherapeutic options. Highly substituted ansa-titanocene compounds have shown promising cytotoxic activity in a range of cancers. The objectives of this study are to examine the effects of these titanocene compounds on prostate cancer cells. Prostate cell lines were treated with three novel titanocene compounds and compared to titanocene dichloride and cisplatin. Percent apoptosis, viability and cell cycle were assessed using propidium iodide DNA incorporation with flow cytometry. Cytochrome C was assessed by western blotting of mitochondrial and cytoplasmic fractions. Apoptosis Inducing Factor was assessed by confocal microscopy. These novel compounds induced more apoptosis compared to cisplatin in a dose dependent manner. Compound Y had the most significant effect on cell cycle and apoptosis. Despite the release of cytochrome C from the mitochondrial fraction there was no inhibition of apoptosis with the pan caspase inhibitor, ZVAD-FMK. AIF was shown to translocate from the cytosol to the nucleus mediating a caspase independent cell death. Bcl-2 over expressing PC-3 cells, which were resistant to cisplatin induced apoptosis, underwent apoptosis following treatment with all the titanocene compounds. This study demonstrates possible mechanisms by which these novel titanocene compounds can mediate their apoptotic effect in vitro. The fact that they can induce more apoptosis than cisplatin in advanced cancer cell lines would confer an advantage over cisplatin. They represent exciting new agents with future potential for the treatment of advanced prostate cancer.

Transforming growth factor-beta (TGF-β) in acute injuries of the spinal cord

Injuries to the spinal cord may be associated with increased healing of fractures. This can be of benefit, but excessive bone growth can also cause considerable adverse effects.

We evaluated two groups of patients with fractures of the spinal column, those with neurological compromise (n = 10) and those without (n = 15), and also a control group with an isolated fracture of a long bone (n = 12). The level of transforming growth factor-beta (TGF-β), was measured at five time points after injury (days 1, 5, 10, 42 and 84).

The peak level of 142.79 ng/ml was found at day 84 in the neurology group (p < 0.001 vs other time points). The other groups peaked at day 42 and had a decrease at day 84 after injury (p ≤ 0.001).

Our findings suggest that TGF-β may have a role in the increased bone turnover and attendant complications seen in patients with acute injuries to the spinal cord.

Testicular vasculitis mimicking a testicular neoplasm

Vasculitis of the testis generally presents as a manifestation of systemic vasculitis which is well documented. In isolation, it has only been described on few occasions previously, and hitherto it has been in the young. It often mimics a neoplasm of the testis resulting in radical orchidectomy, only for it to be diagnosed when the specimen is examined under the microscope. In our case, an elderly man presented to us with a presumed testicular neoplasm, however, despite strong clinical and radiological suspicion a testicular vasculitis in isolation was revealed. Following our experience, we performed a literature review and examined all of the cases of testicular vasculitis reported so far and present our findings. We report the general clinical presentation, methods of investigation and subsequent management. This is the first time it has been described in the elderly population.

Hypoxia inhibits human bladder smooth muscle cell proliferation: a potential mechanism of bladder dysfunction

AIMS

Recent animal studies have suggested that bladder outflow obstruction causes bladder wall hypoxia during both the filling and the voiding phases of the micturition cycle. We have previously demonstrated that mechanical deformation of human detrusor leads to smooth muscle (SM) cell hypertrophy and hyperplasia, which may then contribute to hypoxia in the dysfunctional bladder. We hypothesise that the detrusor's response to a hypoxic environment contributes to bladder dysfunction. The aim of this study was to evaluate the effect of hypoxia on detrusor cell survival and growth.

METHODS

Normal human detrusor muscle was obtained at radical cystectomy and primary cultures were established. Cells were then cultured in the presence of 1% oxygen in a hypoxic chamber for different times. Apoptosis was assessed by propidium iodide DNA staining and flow cytometry. Proliferation was assessed by radiolabelled thymidine incorporation. Cell supernatants were retained for growth factor estimation by enzyme linked immuno-sorbent assay (ELISA), and total cell and nuclear extracts were isolated for Western blotting.

RESULTS

SM cells responded to the presence of hypoxia through significant upregulation of survival factors hypoxia inducible factor (HIF 1alpha) and vascular endothelial growth factor (VEGF) in a time-dependent manner. Hypoxia did not induce cell death, but significantly reduced the rate of proliferation over time, associated with an increase in the cell cycle inhibitor p27kip1.

CONCLUSIONS

In an in vitro human detrusor cell culture model, cells demonstrate a resistance to hypoxia-induced apoptosis but proliferation is inhibited. We suggest that the anti-proliferative effects of hypoxia may limit the ability of detrusor cells to respond to, and compensate for, alterations in their environment contributing to bladder dysfunction.