Twist1-induced activation of human fibroblasts promotes matrix stiffness by upregulating palladin and collagen α1(VI)

The transcription factor Twist1 is involved in the epithelial-mesenchymal transition and contributes to cancer metastasis through mostly unknown mechanisms. In colorectal cancer, Twist1 expression is mainly restricted to the tumor stroma. We found that human fibroblast cell lines stably transfected with Twist1 acquired characteristics of activated cancer-associated fibroblasts (CAFs), such as hyperproliferation, an increased ability to migrate and an alignment of the actin cytoskeleton. Further, Twist1-activated fibroblasts promoted increased matrix stiffness. Using quantitative proteomics, we identified palladin and collagen α1(VI) as two major mediators of the Twist1 effects in fibroblast cell lines. Co-immunoprecipitation studies indicated that palladin and Twist1 interact within the nucleus, suggesting that palladin could act as a transcription regulator. Palladin was found to be more relevant for the cellular biomechanical properties, orientation and polarity, and collagen α1(VI) for the migration and invasion capacity, of Twist1-activated fibroblasts. Both palladin and collagen α1(VI) were observed to be overexpressed in colorectal CAFs and to be associated with poor colorectal cancer patient survival and relapse prediction. Our results demonstrate that Twist1-expressing fibroblasts mimic the properties of CAFs present at the tumor invasive front, which likely explains the prometastatic activities of Twist1. Twist1 appears to require both palladin and collagen α1(VI) as downstream effectors for its prometastatic effects, which could be future therapeutic targets in cancer metastasis.

Diagnosis of sarcoidosis in the endobronchial ultrasound-guided transbronchial needle aspiration era

BACKGROUND

Sarcoidosis is a multisystemic disorder of unknown etiology. Its diagnosis is based on compatible clinical and radiological features and supported by histological demonstration of epithelioid cell noncaseating granulomas with exclusion of other causes. Endobronchial ultrasound combined with transbronchial needle aspiration (EBUS-TBNA) has been proposed as a valuable tool in obtaining suitable tissue sample. The aim of this study was to evaluate the contribution of EBUS-TBNA to the diagnosis of stages I and II thoracic sarcoidosis in a community-based hospital.

METHODS

A prospective study was conducted in patients with suspected stages I and II pulmonary sarcoidosis, based on clinical and radiological data, who were being followed in our Interstitial Lung Disorders Outpatient Clinic or sent from other hospitals to our Respiratory Endoscopy Unit for diagnostic procedures. All suitable and fit patients underwent EBUS-TBNA between March 2010 and June 2013. We assessed demographic characteristics, radiological stages, cytological/histological examination and diagnostic techniques performed.

RESULTS

In the period considered 39 patients underwent EBUS-TBNA for suspected stages I and II thoracic sarcoidosis and adequate samples were obtained in 38 (97.4%). Within this population, 33 (84.6%) patients had a definite diagnosis of sarcoidosis, of which 31 patients (93.9%) were confirmed to have epithelioid noncaseating granulomas by EBUS-TBNA. Four patients were submitted to surgical procedures (three to mediastinoscopy and one to open surgical lung biopsy). Data analysis allowed to calculate a sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of 93.9%, 100%, 100%, 75.0% and 94.8%, respectively. No complications were observed.

CONCLUSIONS

EBUS-TBNA is a valuable tool in the diagnostic workup of patients with suspected stages I and II thoracic sarcoidosis providing a substantial number of pathological confirmations and with few complications. Its high diagnostic accuracy precludes the need for more invasive procedures such as surgical biopsy.

Airways changes related to air pollution exposure in wheezing children

In this study, we aimed to evaluate the relationship between individual total exposure to air pollution and airway changes in a group of 51 wheezing children. Respiratory status was assessed four times (January 2006, June 2006, January 2007 and June 2007) during a 1-week period through a standardised questionnaire, spirometry, exhaled nitric oxide fraction and pH in exhaled breath condensate (EBC). Concentrations of particles with a 50% cut-off aerodynamic diameter of 10 µm (PM(10)), O(3), NO(2) and volatile organic compounds were estimated through direct measurements with an ad hoc device or air pollution modelling in the children's schools and at their homes in the same 4 weeks of the study. For each child, total exposure to the different air pollutants was estimated as a function of pollutant concentrations and daily activity patterns. Increasing total exposure to PM(10), NO(2), benzene, toluene and ethylbenzene was significantly associated with a decrease of forced expiratory volume in 1 s (FEV(1)) and with an increase of change in FEV(1). Increasing exposure to NO(2) and benzene was also related to a significant decrease of FEV(1)/forced vital capacity. Increasing exposure to PM(10), NO(2), benzene and ethylbenzene was associated with acidity of EBC. This study suggests an association in wheezing children between airway changes and total exposure to air pollutants, as estimated by taking into account the concentration in the various microenvironments attended by the children.