Activation of Oxidative Stress Response in Cancer Generates a Druggable Dependency on Exogenous Non-essential Amino Acids

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Epithelial-mesenchymal co-culture model for studying alveolar morphogenesis

Division of large, immature alveolar structures into smaller, more numerous alveoli increases the surface area available for gas exchange. Alveolar division requires precise epithelial-mesenchymal interactions. However, few experimental models exist for studying how these cell-cell interactions produce changes in 3-dimensional structure. Here we report an epithelial-mesenchymal cell co-culture model where 3-dimensional peaks form with similar cellular orientation as alveolar structures in vivo. Co-culturing fetal mouse lung mesenchyme with A549 epithelial cells produced tall peaks of cells covered by epithelia with cores of mesenchymal cells. These structures did not form when using adult lung fibroblasts. Peak formation did not require localized areas of cell proliferation or apoptosis. Mesenchymal cells co-cultured with epithelia adopted an elongated cell morphology closely resembling myofibroblasts within alveolar septa in vivo. Because inflammation inhibits alveolar formation, we tested the effects of E. coli lipopolysaccharide on 3-dimensional peak formation. Confocal and time-lapse imaging demonstrated that lipopolysaccharide reduced mesenchymal cell migration, resulting in fewer, shorter peaks with mesenchymal cells present predominantly at the base. This epithelial-mesenchymal co-culture model may therefore prove useful in future studies of mechanisms regulating alveolar morphogenesis.     

Atrial fibrillation after thoracic surgery for lung cancer: use of a single cut-off value of N-terminal pro-B type natriuretic peptide to identify patients at risk

Postoperative atrial fibrillation (AF) is a well-known complication occurring after thoracic surgery. B-type natriuretic peptide has recently been investigated as a predictive marker of postoperative AF after cardiac surgery. The aim of this study was to evaluate a definite cut-off for N-terminal pro-B type natriuretic peptide (NT-proBNP) in predicting postoperative AF in lung cancer patients. NT-proBNP was determined before and after surgery in 400 patients. Cardiac function was monitored by continuous postoperative ECG and clinical cardiological evaluation. AF occurred in 18% of the patients. Receiver operating characteristic curve analyses identified a cut-off of 182.3?ng l^?1 as the one with the highest sensitivity and specificity. Perioperative increased levels of NT-proBNP seem to predict postoperative AF in patients undergoing thoracic surgery, and a single cut-off of 182.3?ng l^?1 can be used to select high-risk patients who could receive preventive therapy, leading to a considerable decrease in the total costs associated with the management of this complication.     

In vivo Measurement of the Mouse Pulmonary Endothelial Surface Layer

The endothelial glycocalyx is a layer of proteoglycans and associated glycosaminoglycans lining the vascular lumen. In vivo, the glycocalyx is highly hydrated, forming a substantial endothelial surface layer (ESL) that contributes to the maintenance of endothelial function. As the endothelial glycocalyx is often aberrant in vitro and is lost during standard tissue fixation techniques, study of the ESL requires use of intravital microscopy. To best approximate the complex physiology of the alveolar microvasculature, pulmonary intravital imaging is ideally performed on a freely-moving lung. These preparations, however, typically suffer from extensive motion artifact. We demonstrate how closed-chest intravital microscopy of a freely-moving mouse lung can be used to measure glycocalyx integrity via ESL exclusion of fluorescently-labeled high molecular weight dextrans from the endothelial surface. This non-recovery surgical technique, which requires simultaneous brightfield and fluorescent imaging of the mouse lung, allows for longitudinal observation of the subpleural microvasculature without evidence of inducing confounding lung injury.     

The Use of the Ex Vivo Chandler Loop Apparatus to Assess the Biocompatibility of Modified Polymeric Blood Conduits

The foreign body reaction occurs when a synthetic surface is introduced to the body. It is characterized by adsorption of blood proteins and the subsequent attachment and activation of platelets, monocyte/macrophage adhesion, and inflammatory cell signaling events, leading to post-procedural complications. The Chandler Loop Apparatus is an experimental system that allows researchers to study the molecular and cellular interactions that occur when large volumes of blood are perfused over polymeric conduits. To that end, this apparatus has been used as an ex vivo model allowing the assessment of the anti-inflammatory properties of various polymer surface modifications. Our laboratory has shown that blood conduits, covalently modified via photoactivation chemistry with recombinant CD47, can confer biocompatibility to polymeric surfaces. Appending CD47 to polymeric surfaces could be an effective means to promote the efficacy of polymeric blood conduits. Herein is the methodology detailing the photoactivation chemistry used to append recombinant CD47 to clinically relevant polymeric blood conduits and the use of the Chandler Loop as an ex vivo experimental model to examine blood interactions with the CD47 modified and control conduits.     

Circular RNA WHSC1 exerts oncogenic properties by regulating miR-7/TAB2 in lung cancer

Circular RNA is a newly discovered member of non-coding RNA (ncRNA) and regulates the target gene by acting as a micro-RNA sponge. It plays vital roles in various diseases. However, the functions of circular RNA in non-small cell lung cancer (NSCLC) remain still unclear. Our data showed that circ-WHSC1 was highly expressed in NSCLC cells and tissues. Both in vitro and in vivo experiments showed that circ-WHSC1 promoted NSCLC proliferation. circ-WHSC1 also promoted the migration and invasion of lung cancer cells. Through bioinformatic analysis and functional experiments, we showed that circ-WHSC1 could act as a sponge for micro-RNA-7 (miR-7) and regulate the expression of TAB2 (TGF-beta activated kinase one binding protein two). Inhibition of the circ-WHSC1/miR-7/TAB2 pathway could effectively attenuate lung cancer progression. In summary, this study confirmed the existence and oncogenic function of circ-WHSC1 in NSCLC. The research suggests that the circ-WHSC1/miR-7/TAB2 axis might be a potential target for NSCLC therapy.     

Correlation of urinary inflammatory and oxidative stress markers in very low birth weight infants with subsequent development of bronchopulmonary dysplasia

Abstract

Currently, bronchopulmonary dysplasia (BPD) occurs almost exclusively in pre-term infants. In addition to prematurity, other factors like oxygen toxicity and inflammation can contribute to the pathogenesis. This study aimed to compare urinary inflammatory and oxidative stress markers between the no/mild BPD group and moderate/severe BPD group and between BPD cases with significant early lung disease like respiratory distress syndrome (RDS) (‘classic’ BPD) and with minimal early lung disease (‘atypical’ BPD). A total of 60 patients who were a gestational age < 30 weeks or a birth weight < 1250 g were included. Urine samples were obtained on the 1^st, 3^rd and 7^th day of life and measured the levels of leukotriene E₄ (LTE₄) and 8-hydroxydeoxyguanosine (8-OHdG). The 8-OHdG values on the 3^rd day showed significant correlation to duration of mechanical ventilation. The 8-OHdG levels on the 7^th day were the independent risk factor for developing moderate/severe BPD. In ‘classic’ BPD, the 8-OHdG values on the 3^rd day were higher than those of ‘atypical’ BPD. In ‘atypical’ BPD, the LTE₄ values on the 7^th day were higher than the values in ‘classic’ BPD. These results suggest that oxidative DNA damage could be the crucial mechanism in the pathogenesis of current BPD and the ongoing inflammatory process could be an important mechanism in ‘atypical’ BPD.     

In Vivo Evidence for Serine Biosynthesis-Defined Sensitivity of Lung Metastasis,but Not of Primary Breast Tumors,to mTORC1 Inhibition

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