Proteasome inhibitors as anti-cancer agents

The ubiquitin (Ub)-proteasome pathway is the major nonlysosomal pathway of proteolysis in human cells and accounts for the degradation of most short-lived, misfolded or damaged proteins. This pathway is important in the regulation of a number of key biological regulatory mechanisms. Proteins are usually targeted for proteasome-mediated degradation by polyubiquitinylation, the covalent addition of multiple units of the 76 amino acid protein Ub, which are ligated to 1-amino groups of lysine residues in the substrate. Polyubiquitinylated proteins are degraded by the 26S proteasome, a large, ATP-dependent multicatalytic protease complex, which also regenerates monomeric Ub. The targets of this pathway include key regulators of cell proliferation and cell death. An alternative form of the proteasome, termed the immunoproteasome, also has important functions in the generation of peptides for presentation by MHC class I molecules. In recent years there has been a great deal of interest in the possibility that proteasome inhibitors, through elevation of the levels of proteasome targets, might prove useful as a novel class of anti-cancer drugs. Here we review the progress made to date in this area and highlight the potential advantages and weaknesses of this approach.

Clinical utility of mental state screening as a predictor of intellectual outcomes 6 months after diagnosis of type 1 diabetes

Background Screening tests of basic cognitive status or ‘mental state’ have been shown to predict mortality and functional outcomes in adults. This study examined the relationship between mental state and outcomes in children with type 1 diabetes. Objective We aimed to determine whether mental state at diagnosis predicts longer term cognitive function of children with a new diagnosis of type 1 diabetes. Methods Mental state of 87 patients presenting with newly diagnosed type 1 diabetes was assessed using the School-Years Screening Test for the Evaluation of Mental Status. Cognitive abilities were assessed 1 wk and 6 months postdiagnosis using standardized tests of attention, memory, and intelligence. Results Thirty-seven children (42.5%) had reduced mental state at diagnosis. Children with impaired mental state had poorer attention and memory in the week following diagnosis, and, after controlling for possible confounding factors, significantly lower IQ at 6 months compared to those with unimpaired mental state (p < 0.05). Conclusions Cognition is impaired acutely in a significant number of children presenting with newly diagnosed type 1 diabetes. Mental state screening is an effective method of identifying children at risk of ongoing cognitive difficulties in the days and months following diagnosis. Clinicians may consider mental state screening for all newly diagnosed diabetic children to identify those at risk of cognitive sequelae.

Challenges of Measuring Learning Outcomes for Property Students Engaged in Work Integrated Learning

Work integrated learning (WIL) or professional practice units are recognised as providing learning experiences that help students make successful transitions to professional practice. These units require students to engage in learning in the workplace; to reflect on this learning; and to integrate it with learning at university. However, an analysis of a recent cohort of property economics students at a large urban university provides evidence that there is great variation in work based learning experiences undertaken and that this impacts on students’capacity to respond to assessment tasks which involve critiquing these experiences in the form of reflective reports. This paper highlights the need to recognise the diversity of work based experiences; the impact this has on learning outcomes; and to find more effective and equitable ways of measuring these outcomes. The paper briefly discusses assessing learning outcomes in WIL and then describes the model of WIL in the Faculty of Built Environment and Engineering at the Queensland University of Technology (QUT). The paper elaborates on the diversity of students’ experiences and backgrounds including variations in the length of work experience, placement opportunities and conditions of employment.For example, the analysis shows that students with limited work experience often have difficulty critiquing this work experience and producing high level reflective reports. On the other hand students with extensive, discipline relevant work experience can be frustrated by assessment requirements that do not take their experience into account. Added to this the Global Financial Crisis (GFC) has restricted both part time and full time placement opportunities for some students. These factors affect students’ capacity to a) secure a relevant work experience, b) reflect critically on the work experiences and c) appreciate the impact the overall experience can have on their learning outcomes and future professional opportunities. Our investigation highlights some of the challenges faced in implementing effective and equitable approaches across diverse student cohorts. We suggest that increased flexibility in assessment requirements and increased feedback from industry may help address these challenges.

The role of insulin in advanced prostate cancer

Advanced prostate cancer is a common and generally incurable disease. Androgen deprivation therapy is used to treat advanced prostate cancer with good benefits to quality of life and regression of disease. Prostate cancer invariably progresses however despite ongoing treatment, to a castrate resistant state. Androgen deprivation is associated with a form of metabolic syndrome, which includes insulin resistance and hyperinsulinaemia. The mitogenic and anti-apoptotic properties of insulin acting through the insulin and hybrid insulin/IGF-1 receptors seem to have positive effects on prostate tumour growth. This pilot study was designed to assess any correlation between elevated insulin levels and progression to castrate resistant prostate cancer. Methods: 36 men receiving ADT for advanced prostate cancer were recruited, at various stages of their treatment, along with 47 controls, men with localised prostate cancer pre-treatment. Serum measurements of C-peptide (used as a surrogate marker for insulin production) were performed and compared between groups. Correlation between serum C-peptide level and time to progression to castrate resistant disease was assessed. Results: There was a significant elevation of C-peptide levels in the ADT group (mean = 1639pmol/L)) compared to the control group (mean = 1169pmol/L), with a p-value of 0.025. In 17 men with good initial response to androgen deprivation, a small negative trend towards earlier progression to castrate resistance with increasing C-peptide level was seen in the ADT group (r = -0.050), however this did not reach statistical significance (p>0.1). Conclusions: This pilot study confirms an increase in serum C-peptide levels in men receiving ADT for advance prostate cancer. A non-significant, but negative trend towards earlier progression to castrate resistance with increasing C-peptide suggests the need for a formal prospective study assessing this hypothesis.

Development of a 3D culture system to study the skeletal metastasis of prostate cancer

In the cancer research field, most in vitro studies still rely on two-dimensional (2D) cultures. However, the trend is rapidly shifting towards using a three-dimensional (3D) culture system. This is because 3D models better recapitulate the microenvironment of cells, and therefore, yield cellular and molecular responses that more accurately describe the pathophysiology of cancer. By adopting technology platforms established by the tissue engineering discipline, it is now possible to grow cancer cells in extracellular matrix (ECM)-like environments and dictate the biophysical and biochemical properties of the matrix. In addition, 3D models can be modified to recapitulate different stages of cancer progression for instance from the initial development of tumor to metastasis. Inevitably, to recapitulate a heterotypic condition, comprising more than one cell type, it requires a more complex 3D model. To date, 3D models that are available for studying the prostate cancer (CaP)-bone interactions are still lacking. Therefore, the aim of this study is to establish a co-culture model that allows investigation of direct and indirect CaP-bone interactions. Prior to that, 3D polyethylene glycol (PEG)-based hydrogel cultures for CaP cells were first developed and growth conditions were optimised. Characterization of the 3D hydrogel cultures show that LNCaP cells form a multicellular mass that resembles avascular tumor. In comparison to 2D cultures, besides the difference in cell morphology, the response of LNCaP cells to the androgen analogue (R1881) stimulation is different compared to the cells in 2D cultures. This discrepancy between 2D and 3D cultures is likely associated with the cell-cell contact, density and ligand-receptor interactions. Following the 3D monoculture study, a 3D direct co-culture model of CaP cells and the human tissue engineered bone (hTEBC) construct was developed. Interactions between the CaP cells and human osteoblasts (hOBs) resulted in elevation of Matrix Metalloproteinase 9 (MMP9) for PC-3 cells and Prostate Specific Antigen (PSA) for LNCaP cells. To further investigate the paracrine interaction of CaP cells and (hOBs), a 3D indirect co-culture model was developed, where LNCaP cells embedded within PEG hydrogels were co-cultured with hTEBC. It was found that the cellular changes observed reflect the early event of CaP colonizing the bone site. In the absence of androgens, interestingly, up-regulation of PSA and other kallikreins is also detected in the co-culture compared to the LNCaP monoculture. This non androgenic stimulation could be triggered by the soluble factors secreted by the hOB such as Interleukin-6. There are also decrease in alkaline phosphatase (ALP) activity and down-regulation of genes of the hOB when co-cultured with LNCaP cells that have not been previously described. These genes include transforming growth factor β1 (TGFβ1), osteocalcin and Vimentin. However, no changes to epithelial markers (e.g E-cadherin, Cytokeratin 8) were observed in both cell types from the co-culture. Some of these intriguing changes observed in the co-cultures that had not been previously described have enriched the basic knowledge of the CaP cell-bone interaction. From this study, we have shown evidence of the feasibility and versatility of our established 3D models. These models can be adapted to test various hypotheses for studies pertaining to underlying mechanisms of bone metastasis and could provide a vehicle for anticancer drug screening purposes in the future.

The relationship between lower intelligence, crime and custodial outcomes : a brief literary review of a vulnerable group

The relationship between intellectual functioning and criminal offending has received considerable focus within the literature. While there remains debate regarding the existence (and strength) of this relationship, there is a wider consensus that individuals with below average functioning (in particular cognitive impairments) are disproportionately represented within the prison population. This paper focuses on research that has implications for the effective management of lower functioning individuals within correctional environments as well as the successful rehabilitation and release of such individuals back into the community. This includes a review of the literature regarding the link between lower intelligence and offending and the identification of possible factors that either facilitate (or confound) this relationship. The main themes to emerge from this review are that individuals with lower intellectual functioning continue to be disproportionately represented in custodial settings and that there is a need to increase the provision of specialised programs to cater for their needs. Further research is also needed into a range of areas including: (1) the reason for this over-representation in custodial settings, (2) the existence and effectiveness of rehabilitation and release programs that cater for lower IQ offenders, (3) the effectiveness of custodial alternatives for this group (e.g. intensive corrections orders) and (4) what post-custodial release services are needed to reduce the risk of recidivism.

Evaluation of an intervention to promote protective infant feeding practices to prevent childhood obesity : outcomes of the NOURISH RCT at 14 months of age and 6 months post the first of two intervention modules

OBJECTIVE: To evaluate a universal obesity prevention intervention, which commenced at infant age 4-6 months, using outcome data assessed 6-months after completion of the first of two intervention modules and 9 months from baseline. DESIGN: Randomised controlled trial of a community-based early feeding intervention. SUBJECTS AND METHODS: 698 first-time mothers (mean age 30±5 years) with healthy term infants (51% male) aged 4.3±1.0 months at baseline. Mothers and infants were randomly allocated to self-directed access to usual care or to attend two group education modules, each delivered over three months, that provided anticipatory guidance on early feeding practices. Outcome data reported here were assessed at infant age 13.7±1.3 months. Anthropometrics were expressed as z-scores (WHO reference). Rapid weight gain was defined as change in weight-for-age z-score (WAZ) > +0.67. Maternal feeding practices were assessed via self-administered questionnaire. RESULTS: There were no differences according to group allocation on key maternal and infant characteristics. At follow up (n=598 [86%]) the intervention group infants had lower BMIZ (0.42±0.85 vs 0.23±0.93, p=0.009) and infants in the control group were more likely to show rapid weight gain from baseline to follow up (OR=1.5 CI95%1.1-2.1, p=0.014). Mothers in the control group were more likely to report using non- responsive feeding practices that fail to respond to infant satiety cues such as encouraging eating by using food as a reward (15% vs 4%, p=0.001) or using games ( 67% vs 29%, p<0.001). CONCLUSIONS: These results provide early evidence that anticipatory guidance targeting the ‘when, what and how’ of solid feeding can be effective in changing maternal feeding practices and, at least in the short term, reducing anthropometric indicators of childhood obesity risk. Analyses of outcomes at later ages are required to determine if these promising effects can be sustained.

Quality-of-life among head and neck cancer survivors at one year after treatment – A systematic review

Abstract Background: The importance of quality-of-life (QoL) research has been recognised over the past two decades in patients with head and neck (H&N) cancer. The aims of this systematic review are to evaluate the QoL status of H&N cancer survivors one year after treatment and to identify the determinants affecting their QoL. Methods: Pubmed, Medline, Scopus, Sciencedirect and CINAHL (2000–2011) were searched for relevant studies, and two of the present authors assessed their methodological quality. The characteristics and main findings of the studies were extracted and reported. Results: Thirty-seven studies met the inclusion criteria, and the methodological quality of the majority was moderate to high. While patients of the group in question recover their global QoL by 12 months after treatment, a number of outstanding issues persist – deterioration in physical functioning, fatigue, xerostomia and sticky saliva. Age, cancer site, stage of disease, social support, smoking, feeding tube placement and alcohol consumption are the significant determinants of QoL at 12 months, while gender has little or no influence. Conclusions: Regular assessments should be carried out to monitor physical functioning,degree of fatigue, xerostomia and sticky saliva. Further research is required to develop appropriate and effective interventions to deal with these issues, and thus to promote the patients’ QoL.

Differential effects of ERP systems on user outcomes : a longitudinal investigation

Adopting a model of job enrichment we report on a longitudinal case investigating the perceived impact of an Enterprise Resource Planning (ERP) system on user job design characteristics. Our results indicated that in the context of an ERP geared towards centralisation and standardisation the extent to which users perceived an increase or decrease in job enrichment was associated with aspects such as formal authority and the nature of their work role. Experienced operational employees proficient in the original legacy system perceived ERP system protocols to constrain their actions, limit training and increase dependence on others in the workflow. Conversely, managerial users reported a number of benefits relating to report availability, improved organisational transparency and increased overall job enrichment. These results supported our argument concerning the relationship between ERPs with a standardisation intent and positive job enrichment outcomes for managerial users and negative job-related outcomes for operational users.

Clusterin is a critical downstream mediator of stress-induced YB-1 transactivation in prostate cancer

Clusterin is a stress-activated, cytoprotective chaperone that confers broad-spectrum treatment resistance in cancer. However, the molecular mechanisms mediating CLU transcription following anticancer treatment stress remain incompletely defined. We report that Y-box binding protein-1 (YB-1) directly binds to CLU promoter regions to transcriptionally regulate clusterin expression. In response to endoplasmic reticulum stress inducers, including paclitaxel, YB-1 is translocated to the nucleus to transactivate clusterin. Furthermore, higher levels of activated YB-1 and clusterin are seen in taxane-resistant, compared with parental, prostate cancer cells. Knockdown of either YB-1 or clusterin sensitized prostate cancer cells to paclitaxel, whereas their overexpression increased resistance to taxane. Clusterin overexpression rescued cells from increased paclitaxel-induced apoptosis following YB-1 knockdown; in contrast, however, YB-1 overexpression did not rescue cells from increased paclitaxel-induced apoptosis following clusterin knockdown. Collectively, these data indicate that YB-1 transactivation of clusterin in response to stress is a critical mediator of paclitaxel resistance in prostate cancer. Mol Cancer Res; 9(12); 1755–66.

Purine Nucleoside Phosphorylase mediated molecular chemotherapy and conventional chemotherapy: A tangible union against chemoresistant cancer

Background Late stage Ovarian Cancer is essentially incurable primarily due to late diagnosis and its inherent heterogeneity. Single agent treatments are inadequate and generally lead to severe side effects at therapeutic doses. It is crucial to develop clinically relevant novel combination regimens involving synergistic modalities that target a wider repertoire of cells and lead to lowered individual doses. Stemming from this premise, this is the first report of two- and three-way synergies between Adenovirus-mediated Purine Nucleoside Phosphorylase based gene directed enzyme prodrug therapy (PNP-GDEPT), docetaxel and/or carboplatin in multidrug-resistant ovarian cancer cells. Methods The effects of PNP-GDEPT on different cellular processes were determined using Shotgun Proteomics analyses. The in vitro cell growth inhibition in differentially treated drug resistant human ovarian cancer cell lines was established using a cell-viability assay. The extent of synergy, additivity, or antagonism between treatments was evaluated using CalcuSyn statistical analyses. The involvement of apoptosis and implicated proteins in effects of different treatments was established using flow cytometry based detection of M30 (an early marker of apoptosis), cell cycle analyses and finally western blot based analyses. Results Efficacy of the trimodal treatment was significantly greater than that achieved with bimodal- or individual treatments with potential for 10-50 fold dose reduction compared to that required for individual treatments. Of note was the marked enhancement in apoptosis that specifically accompanied the combinations that included PNP-GDEPT and accordingly correlated with a shift in the expression of anti- and pro-apoptotic proteins. PNP-GDEPT mediated enhancement of apoptosis was reinforced by cell cycle analyses. Proteomic analyses of PNP-GDEPT treated cells indicated a dowregulation of proteins involved in oncogenesis or cancer drug resistance in treated cells with accompanying upregulation of apoptotic- and tumour- suppressor proteins. Conclusion Inclusion of PNP-GDEPT in regular chemotherapy regimens can lead to significant enhancement of the cancer cell susceptibility to the combined treatment. Overall, these data will underpin the development of regimens that can benefit patients with late stage ovarian cancer leading to significantly improved efficacy and increased quality of life.