RNA-Seq revealed ATF3-regulated inflammation induced by silica.

BACKGROUND: Millions of workers are exposed to dust containing silica. Chronic and over-exposure to silica will lead to silicosis, which is an irreversible and sometimes fatal lung disease. The disordered physiological processes of silicosis consist of accumulation of silica particles in the alveoli of the lung. Then, the ingestion of the silica particles by macrophages was followed by an inflammatory response. Up till now, the chest radiographs remain the key tool in diagnosing and assessing the extent of silicosis. However, concerns exist regarding the sensitivity and specificity of the technique. Therefore, there is still a need to develop a biomarker for silicosis for early detection of silicosis. METHOD: In this study, RNA-Seq was applied to detect the gene expression changes when silica was exposed to macrophages at different time intervals. RNA-Seq provides a broader dynamic range, increased specificity and sensitivity, and easier detection of rare and low-abundance transcripts. Bioinformatics tools such as the Database for Annotation, Visualization and Integrated Discovery (DAVID) and Gene Functional Classification Tool and Search Tool for the Retrieval of Interacting Genes (STRING) were applied for data analysis. Quantitative PCR was used to validate the results. RESULTS: Our results showed that regulation of transcription factors was the dominant activated pathway in early exposure of silica to macrophages, followed by inflammatory responses which were the main mechanisms in silicosis. One of the findings was the upregulation of activating transcription factor 3 (ATF3) during silica exposure. When ATF3 expression was inhibited by siRNA, the production of cytokines IL-1ß, IL-6 and TNF was further increased. CONCLUSION: This indicated that ATF3 may be a potential early diagnostic biomarker for silicosis and ATF3 acts as a repressor in inflammatory responses induced by silica.

Robust and accurate digital measurement for HER2 amplification in HER2 equivocal breast cancer diagnosis.

Currently, there are no recommended alternative assays for HER2 cases deemed equivocal by immunohistochemistry and fluorescent in situ hybridization. Digital PCR (ddPCR), a highly accurate method to determine DNA copy number, could be a robust alternative for clinical HER2 diagnostics. HER2 and CEP17 copy numbers were quantified using two ddPCR platforms (QX200 and RainDrop) in 102 samples of invasive breast cancers. Compared to routine assays, ddPCR gave a sensitivity and specificity of 82.8% and 97.3% respectively, with a kappa value of 0.833 (p < 0.001). Moreover, the method proved to be robust as the results from two platforms was highly correlated (R2 = 0.91; Concordance rate = 97%; κ = 0.923, P < 0.001). Its performance was further tested on 114 HER2 equivocal cases in an independent validation cohort. 75% (21/28) of cases with HER2 amplification and 95% (82/86) of HER2 non-amplified case were classified as positive and negative by ddPCR respectively (κ = 0.709, P < 0.001). Notably, in the HER2 amplified cases, a lower percentage of HER2 positive cells could be related to the discordant results. Altogether, ddPCR is a robust alternative for clinical HER2 diagnostics. However, intratumoral heterogeneity of HER2 status still pose a challenge for HER2 analysis by ddPCR.

Profiling of the silica-induced molecular events in lung epithelial cells using the RNA-Seq approach.

Silicosis is a prolonged, irreversible and incurable occupational disease, and there is a significant number of newly diagnosed cases every year in Hong Kong. Due to the long latency of the disease, the diagnosis can be missed until detailed clinical examination at a later stage. For a better control of this deadly disease, detailing the pro-inflammatory and fibrotic events in the macrophage would be instrumental in understanding the pathogenesis of the disease and essential for the significant biomarkers discovery. In this in vitro study, human cell line model A549 lung epithelial cells were used. The immediate molecular events underneath the activation of quartz silica polymorphs were followed in a time course of 0, 0.5, 2, 8, 16 and 24 h. The transcriptome library was prepared and subjected to RNA-Seq analysis. Data analysis was performed by pathway analysis tools and verified by real-time PCR. The results showed that triggered genes were mainly found in the immune response and inflammatory pathways. An interesting finding was the association of the DNA-binding protein inhibitor (ID) family in the silica exposure to lung cells. The linkage of ID1, ID2 and ID3 to cancer may rationalize themselves to be the markers indicating an early response of silicosis. However, further studies are required to consolidate the roles of these genes in silicosis. Copyright © 2017 John Wiley & Sons, Ltd.

Current Hypothesis for the Relationship between Dietary Rice Bran Intake, the Intestinal Microbiota and Colorectal Cancer Prevention.

Globally, colorectal cancer (CRC) is the third most common form of cancer. The development of effective chemopreventive strategies to reduce CRC incidence is therefore of paramount importance. Over the past decade, research has indicated the potential of rice bran, a byproduct of rice milling, in CRC chemoprevention. This was recently suggested to be partly attributable to modification in the composition of intestinal microbiota when rice bran was ingested. Indeed, previous studies have reported changes in the population size of certain bacterial species, or microbial dysbiosis, in the intestines of CRC patients and animal models. Rice bran intake was shown to reverse such changes through the manipulation of the population of health-promoting bacteria in the intestine. The present review first provides an overview of evidence on the link between microbial dysbiosis and CRC carcinogenesis and describes the molecular events associated with that link. Thereafter, there is a summary of current data on the effect of rice bran intake on the composition of intestinal microbiota in human and animal models. The article also highlights the need for further studies on the inter-relationship between rice bran intake, the composition of intestinal microbiota and CRC prevention.

The 3a protein of severe acute respiratory syndrome-associated coronavirus induces apoptosis in Vero E6 cells.

An outbreak of severe acute respiratory syndrome (SARS) occurred in China and the first case emerged in mid-November 2002. The aetiological agent of this disease was found to be a previously unknown coronavirus, SARS-associated coronavirus (SARS-CoV). The detailed pathology of SARS-CoV infection and the host response to the viral infection are still not known. The 3a gene encodes a non-structural viral protein, which is predicted to be a transmembrane protein. In this study, it was shown that the 3a protein was expressed in the lungs and intestinal tissues of SARS patients and that the protein localized to the endoplasmic reticulum in 3a-transfected monkey kidney Vero E6 cells. In vitro experiments of chromatin condensation and DNA fragmentation suggested that the 3a protein may trigger apoptosis. These data showed that overexpression of a single SARS-CoV protein can induce apoptosis in vitro.