A microenvironment-inspired synthetic three-dimensional model for pancreatic ductal adenocarcinoma organoids.

Experimental in vitro models that capture pathophysiological characteristics of human tumours are essential for basic and translational cancer biology. Here, we describe a fully synthetic hydrogel extracellular matrix designed to elicit key phenotypic traits of the pancreatic environment in culture. To enable the growth of normal and cancerous pancreatic organoids from genetically engineered murine models and human patients, essential adhesive cues were empirically defined and replicated in the hydrogel scaffold, revealing a functional role of laminin-integrin α3/α6 signalling in establishment and survival of pancreatic organoids. Altered tissue stiffness-a hallmark of pancreatic cancer-was recapitulated in culture by adjusting the hydrogel properties to engage mechano-sensing pathways and alter organoid growth. Pancreatic stromal cells were readily incorporated into the hydrogels and replicated phenotypic traits characteristic of the tumour environment in vivo. This model therefore recapitulates a pathologically remodelled tumour microenvironment for studies of normal and pancreatic cancer cells in vitro.

Early Adaptation of Colorectal Cancer Cells to the Peritoneal Cavity Is Associated with Activation of "Stemness" Programs and Local Inflammation.

PURPOSE: At diagnosis, colorectal cancer presents with synchronous peritoneal metastasis in up to 10% of patients. The peritoneum is poorly characterized with respect to its superspecialized microenvironment. Our aim was to describe the differences between peritoneal metastases and their matched primary tumors excised simultaneously at the time of surgery. Also, we tested the hypothesis of these differences being present in primary colorectal tumors and having prognostic capacity. EXPERIMENTAL DESIGN: We report a comprehensive analysis of 30 samples from peritoneal metastasis with their matched colorectal cancer primaries obtained during cytoreductive surgery. We tested and validated the prognostic value of our findings in a pooled series of 660 colorectal cancer primary samples with overall survival (OS) information and 743 samples with disease-free survival (DFS) information from publicly available databases. RESULTS: We identified 20 genes dysregulated in peritoneal metastasis that promote an early increasing role of "stemness" in conjunction with tumor-favorable inflammatory changes. When adjusted for age, gender, and stage, the 20-gene peritoneal signature proved to have prognostic value for both OS [adjusted HR for the high-risk group (vs. low-risk) 2.32 (95% confidence interval, CI, 1.69-3.19; P < 0.0001)] and for DFS [adjusted HR 2.08 (95% CI, 1.50-2.91; P < 0.0001)]. CONCLUSIONS: Our findings indicated that the activation of "stemness" pathways and adaptation to the peritoneal-specific environment are key to early stages of peritoneal carcinomatosis. The in silico analysis suggested that this 20-gene peritoneal signature may hold prognostic information with potential for development of new precision medicine strategies in this setting.

Measurement issues associated with quantitative molecular biology analysis of complex food matrices for the detection of food fraud.

Following a report on a significant amount of horse DNA being detected in a beef burger product on sale to the public at a UK supermarket in early 2013, the Elliott report was published in 2014 and contained a list of recommendations for helping ensure food integrity. One of the recommendations included improving laboratory testing capacity and capability to ensure a harmonised approach for testing for food authenticity. Molecular biologists have developed exquisitely sensitive methods based on the polymerase chain reaction (PCR) or mass spectrometry for detecting the presence of particular nucleic acid or peptide/protein sequences. These methods have been shown to be specific and sensitive in terms of lower limits of applicability, but they are largely qualitative in nature. Historically, the conversion of these qualitative techniques into reliable quantitative methods has been beset with problems even when used on relatively simple sample matrices. When the methods are applied to complex sample matrices, as found in many foods, the problems are magnified resulting in a high measurement uncertainty associated with the result which may mean that the assay is not fit for purpose. However, recent advances in the technology and the understanding of molecular biology approaches have further given rise to the re-assessment of these methods for their quantitative potential. This review focuses on important issues for consideration when validating a molecular biology assay and the various factors that can impact on the measurement uncertainty of a result associated with molecular biology approaches used in detection of food fraud, with a particular focus on quantitative PCR-based and proteomics assays.

Commuting to school: are children who walk more physically active?

BACKGROUND: The journey to school is an opportunity for increasing children's daily physical activity. However, the contribution that active commuting to school makes to overall physical activity is unknown. This study used objective measurement to investigate the physical activity patterns of children by mode of travel to school. METHODS: Primary-school children wore an accelerometer programmed to record minute-by-minute physical activity for 7 days and completed a brief questionnaire describing their usual travel to school. The total volume of physical activity and the time spent in activity of at least moderate intensity, as recorded by the accelerometer, was estimated for weekdays and the weekend, and groups of children were compared by mode of transport to school. Data were collected in May/June 2002. RESULTS: Of the 114 children (59 boys, 55 girls; aged 10.4+/-0.8 years) who took part in the study, those who walked to school (65%) were significantly more active than those who traveled by car (712.0+/-206.7 vs 629.9+/-207.2 accelerometer counts per minute, p=0.05). Analysis by gender indicated that the major differences in physical activity between travel groups were seen only in boys. Hourly activity patterns demonstrated that boys who walked to school were more active after school and throughout the evening than were car users. CONCLUSIONS: In boys, walking to school was associated with higher physical activity after school and during the evening. Active transport may contribute to a more physically active profile, at least for boys, supporting walk-to-school initiatives to increase children's physical activity.