Pyrazolopyrimidines establish MurC as a vulnerable target in Pseudomonas aeruginosa and Escherichia coli

The bacterial peptidoglycan biosynthesis pathway provides multiple targets for antibacterials, as proven by the clinical success of β-lactam and glycopeptide classes of antibiotics. The Mur ligases play an essential role in the biosynthesis of the peptidoglycan building block, N-acetyl-muramic acid-pentapeptide. MurC, the first of four Mur ligases, ligates l-alanine to UDP-N-acetylmuramic acid, initiating the synthesis of pentapeptide precursor. Therefore, inhibiting the MurC enzyme should result in bacterial cell death. Herein, we report a novel class of pyrazolopyrimidines with subnanomolar potency against both Escherichia coli and Pseudomonas aeruginosa MurC enzymes, which demonstrates a concomitant bactericidal activity against efflux-deficient strains. Radio-labeled precursor incorporation showed these compounds selectively inhibited peptidoglycan biosynthesis, and genetic studies confirmed the target of pyrazolopyrimidines to be MurC. In the presence of permeability enhancers such as colistin, pyrazolopyrimidines exhibited low micromolar MIC against the wild-type bacteria, thereby, indicating permeability and efflux as major challenges for this chemical series. Our studies provide biochemical and genetic evidence to support the essentiality of MurC and serve to validate the attractiveness of target for antibacterial discovery.

Radon as a natural tracer for gas transport within uranium waste rock piles

Acid mine drainage (AMD) has been identified as the main cause for outflow of acid water and radioactive/non-radioactive contaminants. AMD encompasses pyrites oxidation when water and oxygen are available. AMD was identified in uranium waste rock piles (WRPs) of Indústrias Nucleares do Brasil-Caldas facility (Brazilian uranium mine), resulting in high costs for water treatment. AMD reduction is the main challenge, and scientific investigation has been conducted to understand oxygen and water transportation within WRPs, where 222Rn is used as natural tracer for oxygen transportation. The study consists of soil radon gas mapping in the top layer of WRP4 using active soil gas pumping, radon adsorption in active charcoal and 222Rn determination using high-resolution gamma-ray spectrometry. A sampling network of 71 points was built where samples were collected at a depth of 40 cm. Soil radon gas concentration ranged from 33.7 to 1484.2 kBq m(-3) with mean concentration of 320.7±263.3 kBq m(-3).

Obesity and overweight in intellectual and non-intellectually disabled children

BACKGROUND

Few studies have compared overweight and obesity in intellectually disabled (ID) and non-intellectually disabled (N-ID) children. This research compared the prevalence of overweight and obesity between a sample of 218 ID and 229 N-ID school pupils in Northern Ireland (NI). Comparison of the physical activity and dietary behaviour of the two groups of school pupils were also undertaken.

METHODS

Each pupil completed (assisted if required) a food intake and physical activity questionnaire. Following this body mass index (BMI) and waist circumference were measured and recorded.

RESULTS

Significantly more ID pupils (72, 33%) were overweight/obese compared with 55 (24%) of the N-ID pupils in accordance with their BMI. ID pupils also had significantly higher waist circumferences. Over a quarter of foods consumed by the pupils were fatty and sugary foods and close to 30% of these foods were eaten by the ID children. Pupils spent most of their time engaging in low levels of activity such as reading, watching TV, on games consoles and listening to music. Pupils with an ID spent fewer hours on moderate and high levels of activities compared with those children with N-ID.

CONCLUSIONS

Results of this study found higher levels of overweight and obesity in this sample than in international published research. Additionally significantly higher numbers of ID pupils were overweight and obese indicating the need for future research and public health to focus on this issue.

Engaging schools in the science of low-energy buildings

This article explores the relationship between the previous UK government's initiative to rebuild and renew secondary schools, and the requirement for improved education for sustainable development in the UK. The documented research utilized a number of mechanisms to engage with pupils in Leicester city schools to increase their awareness, knowledge and understanding of the science and engineering associated with the design and operation of low-energy school buildings. Workshops, discussions with energy and sustainable development experts and inspirational visits to existing low-energy buildings were employed to develop an appreciation for the importance of energy efficiency and best design practice. The results demonstrate an increase in pupils' knowledge and understanding of low-energy school design and additionally a rise in those pupils who are interested in science and would consider it as a career option.

Should the use of probiotics in the preterm be routine?

Does the clinical trials' evidence of benefit justify the routine use of probiotics in the preterm infant? There are many uncertainties surrounding the use of probiotics in the preterm, including the mechanism(s) of action of probiotics, knowledge of who benefits and who might not, whether it is placement of large numbers of bacteria into the small intestine or colonisation that determines efficacy, the forms of microbial adaptation(s) and ecological consequences. There is also a current lack of defined products with associated evidence of safety in the preterm infant. It is argued that one cannot assume safety because of a lack of evidence of harm and that one should take a precautionary approach to the introduction of probiotics into routine neonatal practice. One should also consider how best one might monitor microbiological and ecological consequences and longer-term health outcomes before the introduction of this novel intervention into routine practice.

Impact of second reminder invitation on uptake of screening and cancer detection in BreastCheck

This research aims to quantify the impact of reminder invitations on uptake and cancer detection in Ireland. Examination of BreastCheck's clinical database (2000-2010) to determine number of women screened following first invitation and after reminder; comparison by age group and screening phase with outcomes of recall rate, cancer detection and true positive rates. Of 819,182 first invitations sent 448,974 (54.8%) women attended. 245,157 (66.2%) women attended after reminder invitations, increasing uptake by 29.9% to 694,131 (84.7%) and cancers detected by 1,550 (35%). Women awaiting a reminder were less likely recalled for assessment 9,555 (3.9%) than respondents to first invitation 2,887 (4.04%) (p=0.004). Younger, mainly initial women were more likely recalled for assessment after first invitation. There was no difference between cohorts for cancer detection rate or true positive rate. Reminders increased uptake, supporting international evidence. For programme efficiency attendance at first invitation is optimal. For maximum programme effectiveness attendance must be encouraged with reminders.

Abstract C99: Beyond bortezomib: Development of Millennium's next-generation proteasome inhibitors

Bortezomib (Velcade®) is a proteasome inhibitor that has been approved by the U.S. Food and Drug Administration for the treatment of patients with multiple myeloma or relapsed mantle cell lymphoma. It is currently available in more than 90 countries worldwide. The molecule is an N-capped dipeptidyl boronic acid and its molecular mechanism involves slow-tight binding to the chymotrypsin-like (β5) sites of the 26S proteasome. In the development of Millennium's next generation inhibitors, we have investigated several parameters affecting the drug's activity in biological systems. These include tissue proteasome concentration, blood/plasma partitioning and the kinetics of proteasome inhibition in cultured cells. We find that the abundance of the proteasome (approx. 1–5 μM β5 active site concentration) in cells and tissues together with the slow rate of dissociation of bortezomib from the proteasome (110 min. half-life) led to partitioning of the inhibitor in red blood cells, thereby limiting its distribution to potential sites of therapeutic action. Based on the hypothesis that more rapid dissociation from the proteasome should improve tissue distribution, we have developed an investigational, dipeptidyl boronic acid proteasome inhibitor (MLN9708). MLN9708 displays comparable potency (i.e. similar Ki) to bortezomib for the β5 site of the proteasome but a shorter (18 min.) half-life of dissociation. This affects rapid recovery of proteasome activity in tissue culture cells upon washout of the drug as well as reduced blood/plasma partitioning in mice, supporting the hypothesis that a more rapid equilibrium proteasome inhibitor can improve tissue distribution. MLN9708 is currently in phase 1 clinical trials.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr C99.

Abstract C82: Identification and preclinical characterization of inhibitors of the ubiquitin-activating enzymes UBA1 and UBA6

Millennium Pharmaceuticals, Inc. is dedicated to the discovery and development of novel oncology therapeutics in the area of protein homeostasis. Here we report the identification and characterization of compounds that target the ubiquitin activating enzymes, UBA1 and UBA6. These compounds are mechanism based inhibitors that inactivate the ubiquitin E1 enzymes by forming a ubiquitin compound adduct that remains tightly associated with the E1 adenylate binding site. Treatment of cells with these inhibitors results in cellular effects consistent with known Uba1 biology including rapid loss of E2 ubiquitin thioesters, loss of total ubiquitin conjugates, and accumulation of many ubiquitin proteasome system substrates. Following prolonged treatment, cells primarily arrest in the G2 phase of the cell cycle and ultimately undergo apoptosis. Reflecting the extensive cellular roles of ubiquitin, the compounds also impact global protein turnover, ER stress and DNA damage repair. UBA1 inhibition impairs ubiquitination of PCNA and the Fanconia Anemia protein FANCD2 leading to defective repair of UV induced DNA damage. UBA1 inhibition impacts numerous biological pathways relevant to cancer, results in apoptosis in vitro and is capable of inhibiting tumor growth in mouse xenografts in vivo. These data implicate UBA1 as a target for the treatment of cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr C82.

False-positive Mammographic Screening: Factors Influencing Re-attendance over a Decade of Screening

Introduction

International studies on the effect of false-positive mammographic screening results on subsequent re-attendance at screening are inconsistent.

Setting Breast

Check, the national breast screening programme for the Republic of Ireland, screens women two-yearly. Re-attendance for subsequent screening is approximately 90%.

Objectives and Methods

The aim of this research was to quantify the impact of false-positive mammographic screening results on subsequent re-attendance, using the BreastCheck clinical database with a decade of screening and to determine if age group, assessment procedure, initial or subsequent screening, location of appointment for next screening round and time from recall to non-malignant diagnosis predicted re-attendance.

Results

From programme commencement in 2000 to the end of 2007, 13,352 screening tests resulted in assessment; 11,765 participants were aged 50-62 years and of these 9746 received false-positive results (positive predictive value 17.2%). Following a false-positive recall to assessment, re-attendance at subsequent screening differed significantly by procedure type (open biopsy 80.3%; core biopsy only 90.2%; no tissue sampling 91.4%; P < 0.0001). Re-attendance differed significantly by timing of false-positive assessment in a woman's screening history (first versus subsequent screening, 89.5% versus 93.5%, P < 0.0001) and by location of next screening appointment (screening centre 89.8% versus mobile unit 91.3%, P < 0.01). The longer the period between recall to assessment and non-malignant diagnosis the less likely women were to re-attend. After logistic regression, first screening, older age, open surgical biopsy, re-invitation to screening centre and a longer period between recall and non-malignant diagnosis were significant negative predictors of re-attendance.

Conclusion

Since April 2008 BreastCheck has employed full field digital mammography throughout the programme, with a resulting increase in recalls; re-attendance will be closely monitored.

Attitudes to cancer and cancer prevention: what do people aged 35-54 years think?

The aim of this study was to explore the knowledge, attitudes and behaviours of people in mid-life towards cancer prevention. The study was undertaken in Northern Ireland between 2003 and 2007. This was a mixed methods study using a sequential exploratory design. The theoretical framework was the Theory of Planned Behaviour and the methodology was based on Sutton's framework. There were three methodological stages in the study using focus groups, a large cross-sectional survey and a volunteer sample survey. This paper focuses on the findings of the cross-sectional survey relating to the attitudes of people in mid-life towards cancer and cancer prevention. Findings are considered in relation to the respondents' level of knowledge, age, gender, level of educational attainment and socio-economic status. Evidence from this study shows that attitudes towards cancer and cancer prevention are associated significantly with level of knowledge about cancer, gender, socio-economic status and level of educational attainment. In conclusion, the evidence from this study shows that men, those with a lower level of education, those with a lower level of knowledge and those in a lower socio-economic group were more likely to hold negative attitudes about cancer and cancer prevention.

Preclinical evaluation of the antitumor activity of bortezomib in combination with vitamin C or with epigallocatechin gallate, a component of green tea

Purpose

To investigate whether clinically relevant levels of epigallocatechin gallate (EGCG, a component of green tea) or vitamin C (ascorbic acid) could antagonize bortezomib antitumor activity in CWR22 human prostate xenograft tumors.

Methods

The pharmacokinetics (PK) of EGCG and ascorbic acid were determined in immunocompromised mice and compared with concentrations measured in human PK studies of dietary supplements. Antitumor activity of bortezomib in combination with EGCG or ascorbic acid was determined using several dosing regimens to evaluate different target plasma concentrations of EGCG and ascorbic acid.

Results

Bortezomib dosed twice-weekly at 0.8 mg/kg IV demonstrated tumor growth inhibition (TGI) of 53.9–58.9%. However, when combined with EGCG such that the plasma concentrations of EGCG were >200 μM at the time of bortezomib dosing, all antitumor activity was abrogated (TGI = −17.7%). A lower concentration of EGCG (11–16 μM), which is severalfold higher than measured clinically in humans taking EGCG supplements (0.6–3 μM), was not antagonistic to bortezomib (TGI 63.5%). Pharmacodynamic studies of proteasome inhibition reflected these findings. Ascorbic acid (40 and 500 mg/kg PO daily) was evaluated under a similar study design and did not antagonize bortezomib antitumor activity (TGI 57.2 and 72.2%).

Conclusions

No antagonism of bortezomib is seen in preclinical in vivo experiments, where EGCG or ascorbic acid plasma concentrations are commensurate with dietary or supplemental intake. The data suggest that patients receiving bortezomib treatment do not need to avoid normal dietary consumption of green tea, vitamin C-containing foods, or EGCG or vitamin C dietary supplements.

Electronic supplementary material

The online version of this article (doi:10.1007/s00280-011-1591-2) contains supplementary material, which is available to authorized users.