Background: Lung cancer has high morbidity and mortality worldwide with non-small cell lung cancer (NSCLC) accounting for 85% of the cases. Therapies for lung cancer have relatively poor outcomes and further improvements are required. Circular RNAs have been reported to participate in the occurrence and progression of cancer. Information on the functions and mechanism of circRNAs in lung cancer is limited and needs more exploration. Methods: We detected expression of genes and proteins by qPCR and western blot. Function of circSATB2 was investigated using RNA interference and overexpression assays. Location of circSATB2 was assessed by fluorescence in situ hybridization (FISH). Interaction of circSATB2, miR-326 and FSCN1 was confirmed by dual-luciferase reporter assay. Results: Data from the investigation showed that circSATB2 was highly expressed in NSCLC cells and tissues. circSATB2 positively regulated fascin homolog 1, actin-bundling protein 1 (FSCN1) expression via miR-326 in lung cancer cells. Furthermore, circSATB2 can be transferred by exosomes and promote the proliferation, migration and invasion of NSCLC cells, as well as induce abnormal proliferation in normal human bronchial epithelial cells. Also, circSATB2 was highly expressed in serumal exosomes from lung cancer patients with high sensitivity and specificity for clinical detection and was related to lung cancer metastasis. Conclusions: circSATB2 participated in the progression of NSCLC and was differentially expressed in lung cancer tissue and serumal exosomes. circSATB2 may be potential biomarker for the diagnosis of NSCLC.

Circular RNAs are widely expressed in eukaryotic cells and associated with cancer. However, limited studies to date have focused on the potential role of circRNAs in progression of lung cancer. Data from the current investigation showed that circRNA 100146 is highly expressed in non-small cell lung cancer (NSCLC) cell lines and the chemically induced malignant transformed bronchial cell line, 16HBE-T, as well as 40 paired tissue samples of NSCLC. Suppression of circRNA 100146 inhibited the proliferation and invasion of cells and promoted apoptosis. Furthermore, circRNA 100146 could interact with splicing factors and bind miR-361-3p and miR-615-5p to regulate multiple downstream mRNAs. Our collective findings support a role of circRNA 100146 in the development of NSCLC and further demonstrate endogenous competition among circRNA 100146, SF3B3 and miRNAs, providing novel insights into the mechanisms underlying non-small cell lung cancer.Electronic supplementary materialThe online version of this article (10.1186/s12943-019-0943-0) contains supplementary material, which is available to authorized users.

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AbstractcircNOL10 is a circular RNA expressed at low levels in lung cancer, though its functions in lung cancer remain unknown. Here, the function and molecular mechanism of circNOL10 in lung cancer development are investigated using in vitro and in vivo studies, and it is shown that circNOL10 significantly inhibits the development of lung cancer and that circNOL10 expression is co‐regulated by methylation of its parental gene Pre‐NOL10 and by splicing factor epithelial splicing regulatory protein 1 (ESRP1). circNOL10 promotes the expression of transcription factor sex comb on midleg‐like 1 (SCML1) by inhibiting transcription factor ubiquitination and thus also affects regulation of the humanin (HN) polypeptide family by SCML1. circNOL10 also affects mitochondrial function through regulating the humanin polypeptide family and affecting multiple signaling pathways, ultimately inhibiting cell proliferation and cell cycle progression, and promoting the apoptosis of lung cancer cells, thereby inhibiting lung cancer development. This study investigates the functions and molecular mechanisms of circNOL10 in the development of lung cancer and reveals its involvement in the transcriptional regulation of the HN polypeptide family by SCML1. The results also demonstrate the inhibitory effect of HN on lung cancer cells growth. These findings may identify novel targets for the molecular therapy of lung cancer.

Anaerobic digestion (AD) is a microbial process widely used to treat organic wastes. While the microbes involved in digestion of municipal sludge are increasingly well characterized, the taxonomic and functional compositions of AD digesters treating industrial wastewater have been understudied. This study examined metagenomes from a biogas-producing digester treating municipal sludge in Shek Wu Hui (SWH), Hong Kong and an industrial wastewater digester in Guangzhou (GZ), China, and compared their taxonomic composition and reconstructed biochemical pathways. Genes encoding carbohydrate metabolism and protein metabolism functions were overrepresented in GZ, while genes encoding functions related to fatty acids, lipids and isoprenoids were overrepresented in SWH, reflecting the plants’ feedstocks. Mapping of genera to functions in each community indicated that both digesters had a high level of functional redundancy, and a more even distribution of genera in GZ suggested that it was more functionally stable. While fermentation in both samples was dominated by Clostridia, SWH had an overrepresentation of Proteobacteria, including syntrophic acetogens, reflecting its more complex substrate. Considering the growing importance of biogas as an alternative fuel source, a detailed mechanistic understanding of AD is important and this report will be a basis for further study of industrial wastewater AD.

Pancreatic lipase (PL) is a critical enzyme associated with hyperlipidemia and obesity. A previous study of ours suggested that persimmon tannin (PT) was the main component accounting for the antihyperlipidemic effects of persimmon fruits, but the underlying mechanisms were unclear. In this present study, the inhibitory effect of PT on PL was studied and the possible mechanisms were evaluated by fluorescence spectroscopy, circular dichroism (CD) spectra, isothermal titration calorimetry (ITC), and molecular docking. PT had a high affinity to PL and inhibited the activity of PL with the half maximal inhibitory concertation (IC) value of 0.44 mg/mL in a noncompetitive way. Furthermore, molecular docking revealed that the hydrogen bonding and π-π stacking was mainly responsible for the interaction. The strong inhibition of PT on PL in the gastrointestinal tract might be one mechanism for its lipid-lowering effect.

Cellulose and xylan are two major components of lignocellulosic biomass, which represents a potentially important energy source, as it is abundant and can be converted to methane by microbial action. However, it is recalcitrant to hydrolysis, and the establishment of a complete anaerobic digestion system requires a specific repertoire of microbial functions. In this study, we maintained 2-year enrichment cultures of anaerobic digestion sludge amended with cellulose or xylan to investigate whether a cellulose-or xylan-digesting microbial system could be assembled from sludge previously used to treat neither of them. While efficient methane-producing communities developed under mesophilic (35°C) incubation, they did not under thermophilic (55°C) conditions. Illumina amplicon sequencing results of the archaeal and bacterial 16S rRNA genes revealed that the mature cultures were much lower in richness than the inocula and were dominated by single archaeal (genus Methanobacterium) and bacterial (order Clostridiales) groups, although at finer taxonomic levels the bacteria were differentiated by substrates. Methanogenesis was primarily via the hydrogenotrophic pathway under all conditions, although the identity and growth requirements of syntrophic acetate-oxidizing bacteria were unclear. Incubation conditions (substrate and temperature) had a much greater effect than inoculum source in shaping the mature microbial community, although analysis based on unweighted UniFrac distance found that the inoculum still determined the pool from which microbes could be enriched. Overall, this study confirmed that anaerobic digestion sludge treating nonlignocellulosic material is a potential source of microbial cellulose-and xylan-digesting functions given appropriate enrichment conditions. C ellulose and xylan, two major structural components of plant cell walls, represent important resources for renewable energy (1-3). Cellulose, hemicellulose (the major component is xylan), and lignin make up 35 to 50%, 20 to 35%, and 10 to 25% of total lignocellulose by dry weight, respectively (4). Cellulose and xylan from lignocellulosic biomass not only represent new energy sources but also could reduce carbon dioxide emissions, as lignocellulosic biofuels are considered carbon neutral. However, digesting recalcitrant lignocellulosic components to fermentable sugars is a rate-limiting step (5), making lignocellulosic biofuels currently challenging to produce while being price competitive with fossil fuels (6, 7). Microbes have evolved strategies (8, 9) to digest lignocellulosic components concurrent with the evolution of plant cell walls, making the investigation of microbial cellulose and xylan digestion potentially important to this emerging energy source.Metagenomic and microbial diversity studies of ruminant animals (e.g., cow [10], sheep [11], and deer [12]) have revealed rich taxonomic and functional microbial diversity, including mechanisms for cellulose and xylan digestion. Microbial cellulose and xylan digestion systems have been ide...

BackgroundAlthough anaerobic digestion for biogas production is used worldwide in treatment processes to recover energy from carbon-rich waste such as cellulosic biomass, the activities and interactions among the microbial populations that perform anaerobic digestion deserve further investigations, especially at the population genome level. To understand the cellulosic biomass-degrading potentials in two full-scale digesters, this study examined five methanogenic enrichment cultures derived from the digesters that anaerobically digested cellulose or xylan for more than 2 years under 35 or 55 °C conditions.ResultsMetagenomics and metatranscriptomics were used to capture the active microbial populations in each enrichment culture and reconstruct their meta-metabolic network and ecological roles. 107 population genomes were reconstructed from the five enrichment cultures using a differential coverage binning approach, of which only a subset was highly transcribed in the metatranscriptomes. Phylogenetic and functional convergence of communities by enrichment condition and phase of fermentation was observed for the highly transcribed populations in the metatranscriptomes. In the 35 °C cultures grown on cellulose, Clostridium cellulolyticum-related and Ruminococcus-related bacteria were identified as major hydrolyzers and primary fermenters in the early growth phase, while Clostridium leptum-related bacteria were major secondary fermenters and potential fatty acid scavengers in the late growth phase. While the meta-metabolism and trophic roles of the cultures were similar, the bacterial populations performing each function were distinct between the enrichment conditions.ConclusionsOverall, a population genome-centric view of the meta-metabolism and functional roles of key active players in anaerobic digestion of cellulosic biomass was obtained. This study represents a major step forward towards understanding the microbial functions and interactions at population genome level during the microbial conversion of lignocellulosic biomass to methane. The knowledge of this study can facilitate development of potential biomarkers and rational design of the microbiome in anaerobic digesters.Electronic supplementary materialThe online version of this article (10.1186/s13068-018-1121-0) contains supplementary material, which is available to authorized users.