PGRMC1 phosphorylation affects cell shape, motility, glycolysis, mitochondrial form and function, and tumor growth

BACKGROUND

Progesterone Receptor Membrane Component 1 (PGRMC1) is expressed in many cancer cells, where it is associated with detrimental patient outcomes. It contains phosphorylated tyrosines which evolutionarily preceded deuterostome gastrulation and tissue differentiation mechanisms.

RESULTS

We demonstrate that manipulating PGRMC1 phosphorylation status in MIA PaCa-2 (MP) cells imposes broad pleiotropic effects. Relative to parental cells over-expressing hemagglutinin-tagged wild-type (WT) PGRMC1-HA, cells expressing a PGRMC1-HA-S57A/S181A double mutant (DM) exhibited reduced levels of proteins involved in energy metabolism and mitochondrial function, and altered glucose metabolism suggesting modulation of the Warburg effect. This was associated with increased PI3K/AKT activity, altered cell shape, actin cytoskeleton, motility, and mitochondrial properties. An S57A/Y180F/S181A triple mutant (TM) indicated the involvement of Y180 in PI3K/AKT activation. Mutation of Y180F strongly attenuated subcutaneous xenograft tumor growth in NOD-SCID gamma mice. Elsewhere we demonstrate altered metabolism, mutation incidence, and epigenetic status in these cells.

CONCLUSIONS

Altogether, these results indicate that mutational manipulation of PGRMC1 phosphorylation status exerts broad pleiotropic effects relevant to cancer and other cell biology.

LobSig is a multigene predictor of outcome in invasive lobular carcinoma

Invasive lobular carcinoma (ILC) is the most common special type of breast cancer, and is characterized by functional loss of E-cadherin, resulting in cellular adhesion defects. ILC typically present as estrogen receptor positive, grade 2 breast cancers, with a good short-term prognosis. Several large-scale molecular profiling studies have now dissected the unique genomics of ILC. We have undertaken an integrative analysis of gene expression and DNA copy number to identify novel drivers and prognostic biomarkers, using in-house (n = 25), METABRIC (n = 125) and TCGA (n = 146) samples. Using in silico integrative analyses, a 194-gene set was derived that is highly prognostic in ILC (P = 1.20 × 10-5)-we named this metagene 'LobSig'. Assessing a 10-year follow-up period, LobSig outperformed the Nottingham Prognostic Index, PAM50 risk-of-recurrence (Prosigna), OncotypeDx, and Genomic Grade Index (MapQuantDx) in a stepwise, multivariate Cox proportional hazards model, particularly in grade 2 ILC cases (χ 2, P = 9.0 × 10-6), which are difficult to prognosticate clinically. Importantly, LobSig status predicted outcome with 94.6% accuracy amongst cases classified as 'moderate-risk' according to Nottingham Prognostic Index in the METABRIC cohort. Network analysis identified few candidate pathways, though genesets related to proliferation were identified, and a LobSig-high phenotype was associated with the TCGA proliferative subtype (χ 2, P < 8.86 × 10-4). ILC with a poor outcome as predicted by LobSig were enriched with mutations in ERBB2, ERBB3, TP53, AKT1 and ROS1. LobSig has the potential to be a clinically relevant prognostic signature and warrants further development.

Diagnosis of Recurrent Fracture in a Pediatric Cohort

Significant fracture history in children is defined as having at least one vertebral fracture, at least 2 fractures by age 10, or at least 3 fractures by age 19. Between September 2011 and December 2014, clinical data were collected on children with a significant fracture history that attended a major Australian children's hospital. Fifty-six patients were identified as having 305 fractures in total, including 44 vertebral fractures. 18% of patients (10/56) were diagnosed with osteogenesis imperfecta (OI) by a bone health expert, molecular testing or both, and they sustained 23% of all fractures (71/305). Analysis of serum bone biochemistry showed all median values to be within a normal range and no clinically significant differences between patients with and without OI. The DXA and pQCT derived bone mineral density (BMD) and bone mineral content (BMC) Z scores were reduced overall. DXA derived total body and lumbar spine areal BMD-for-age and BMC-for-age Z scores were significantly lower in children who had vertebral fractures or who were later diagnosed with OI. Similarly, pQCT performed on radii and tibiae showed Z scores significantly less than zero. pQCT-derived limb muscle cross sectional area Z scores were significantly lower in the OI subgroup. In conclusion, this study describes the bone phenotype of children referred to a tertiary hospital clinic for recurrent fractures and highlights a subset of children with previously undiagnosed OI, but a larger cohort without classic OI. Thus it can be clinically challenging to differentiate between children with OI type 1 (mild phenotype) and non-OI children without bone densitometry and genetic testing. We conclude that recurrent fractures in children should prompt a comprehensive bone and systemic health assessment to eliminate an underlying pathology.

Long-term nitrogen dioxide exposure assessment using back-extrapolation of satellite-based land-use regression models for Australia

Assessing historical exposure to air pollution in epidemiological studies is often problematic because of limited spatial and temporal measurement coverage. Several methods for modelling historical exposures have been described, including land-use regression (LUR). Satellite-based LUR is a recent technique that seeks to improve predictive ability and spatial coverage of traditional LUR models by using satellite observations of pollutants as inputs to LUR. Few studies have explored its validity for assessing historical exposures, reflecting the absence of historical observations from popular satellite platforms like Aura (launched mid-2004). We investigated whether contemporary satellite-based LUR models for Australia, developed longitudinally for 2006-2011, could capture nitrogen dioxide (NO₂) concentrations during 1990-2005 at 89 sites around the country. We assessed three methods to back-extrapolate year-2006 NO₂ predictions: (1) 'do nothing' (i.e., use the year-2006 estimates directly, for prior years); (2) change the independent variable 'year' in our LUR models to match the years of interest (i.e., assume a linear trend prior to year-2006, following national average patterns in 2006-2011), and; (3) adjust year-2006 predictions using selected historical measurements. We evaluated prediction error and bias, and the correlation and absolute agreement of measurements and predictions using R² and mean-square error R² (MSE-R²), respectively. We found that changing the year variable led to best performance; predictions captured between 41% (1991; MSE-R² = 31%) and 80% (2003; MSE-R² = 78%) of spatial variability in NO₂ in a given year, and 76% (MSE-R² = 72%) averaged over 1990-2005. We conclude that simple methods for back-extrapolating prior to year-2006 yield valid historical NO₂ estimates for Australia during 1990-2005. These results suggest that for the time scales considered here, satellite-based LUR has a potential role to play in long-term exposure assessment, even in the absence of historical predictor data.

Bibliometric analysis of military trauma publications: 2000-2016

INTRODUCTION

Bibliometric tools can be used to identify the authors, topics and research institutions that have made the greatest impact in a field of medicine. The aim of this research was to analyse military trauma publications over the last 16 years of armed conflict in order to highlight the most important lessons that have translated into civilian practice and military doctrine as well as identify emerging areas of importance.

METHODS

A systematic search of research published between January 2000 and December 2016 was conducted using the Thompson Reuters Web of Science database. Both primary evidence and review publications were included. Results were categorised according to relevance and topic and the 30 most cited publications were reviewed in full. The h-index, impact factors, citation counts and citation analysis were used to evaluate results.

RESULTS

A plateau in the number of annual publications on military trauma was found, as was a shift away from publications on wound and mortality epidemiology to publications on traumatic brain injury (TBI), neurosurgery or blast injury to the head. Extensive collaboration networks exist between highly contributing authors and institutions, but less collaboration between authors from different countries. The USA produced the majority of recent publications, followed by the UK, Germany and Israel.

CONCLUSIONS

In recent years, the number of publications on TBI, neurosurgery or blast injury to the head has increased. It is likely that the lessons of recent conflicts will continue to influence civilian medical practice, particularly regarding the long-term effects of blast-related TBI.

Independent Validation of National Satellite-Based Land-Use Regression Models for Nitrogen Dioxide Using Passive Samplers

Including satellite observations of nitrogen dioxide (NO₂) in land-use regression (LUR) models can improve their predictive ability, but requires rigorous evaluation. We used 123 passive NO₂ samplers sited to capture within-city and near-road variability in two Australian cities (Sydney and Perth) to assess the validity of annual mean NO₂ estimates from existing national satellite-based LUR models (developed with 68 regulatory monitors). The samplers spanned roadside, urban near traffic (≤100 m to a major road), and urban background (>100 m to a major road) locations. We evaluated model performance using R² (predicted NO₂ regressed on independent measurements of NO₂), mean-square-error R² (MSE-R²), RMSE, and bias. Our models captured up to 69% of spatial variability in NO₂ at urban near-traffic and urban background locations, and up to 58% of variability at all validation sites, including roadside locations. The absolute agreement of measurements and predictions (measured by MSE-R²) was similar to their correlation (measured by R²). Few previous studies have performed independent evaluations of national satellite-based LUR models, and there is little information on the performance of models developed with a small number of NO₂ monitors. We have demonstrated that such models are a valid approach for estimating NO₂ exposures in Australian cities.

The long-term effects of switching from active intravenous bisphosphonate treatment to low-dose maintenance therapy in children with osteogenesis imperfecta

BACKGROUND/AIMS

Intravenous bisphosphonate therapy is the first-line treatment in moderate-to-severe osteogenesis imperfecta (OI), but there are varied treatment protocols with little data on long-term efficacy. This study evaluates the clinical outcomes when transitioning from active bisphosphonate treatment to maintenance therapy.

METHODS

A retrospective review was conducted on 17 patients before treatment, following active treatment (zoledronate 0.05 mg/kg 6-monthly or pamidronate 6-9 mg/kg/year) and after establishment on maintenance treatment for more than 2 years (zoledronate 0.025 mg/kg 6-monthly or pamidronate <4 mg/kg/year).

RESULTS

There was a significant reduction in mean fracture rate from 1.5 ± 1.1 fractures/year at baseline to 0.7 ± 0.7 fractures/year on active treatment. Z-scores for lumbar spine bone mineral density, bone mineral content, volumetric bone mineral density and bone mineral content for lean tissue mass increased during active treatment. These improvements were maintained during the period of maintenance treatment. Vertebral height improved in fractured thoracic vertebrae from pre-treatment to active therapy and improved further during maintenance treatment. Metacarpal cortical thickness and relative cortical area also increased over the treatment periods.

CONCLUSION

Maintenance intravenous bisphosphonate therapy preserved the beneficial effects of active treatment at the doses stated above. Further studies are required to determine the optimal bisphosphonate treatment regimen in the management of children with OI.