Expression profiles of circular RNAs in sheep skeletal muscle.

OBJECTIVE: Circular RNAs (circRNAs) are a newfound class of non-coding RNA in animals and plants. Recent studies have revealed that circRNAs play important roles in cell proliferation, differentiation, autophagy and apoptosis during development. However, there are few reports about muscle development-related circRNAs in livestock. METHODS: RNA sequencing analysis was employed to identify and annotate circRNAs from longissimus dorsi of sheep. Reverse transcription followed by real-time quantitative (q) polymerase chain reaction (PCR) analysis verified the presence of these circRNAs. Targetscan7.0 and miRanda were used to analyse the interaction of circRNA-microRNA (miRNA). To investigate the function of circRNAs, an experiment was conducted to perform enrichment analysis hosting genes of circRNAs using gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathways. RESULTS: About 75.5 million sequences were obtained from RNA libraries of sheep skeletal muscle. These sequences were mapped to 729 genes in the sheep reference genome. We identified 886 circRNAs, including numerous circular intronic RNAs and exonic circRNAs. Reverse transcription PCR (RT-PCR) and DNA sequencing analysis confirmed the presence of several circRNAs. Real-Time RT-PCR analysis exhibited resistance of sheep circRNAs to RNase R digestion. We found that many circRNAs interacted with muscle-specific miRNAs involved in growth and development of muscle, especially circ776. The GO and KEGG enrichment analysis showed that hosting genes of circRNAs was involved in muscle cell development and signaling pathway. CONCLUSION: The study provides comprehensive expression profiles of circRNAs in sheep skeletal muscle. Our study offers a large number of circRNAs to facilitate a better understanding of their roles in muscle growth. Meanwhile, we suggested that circ776 could be analyzed in future study.

Polymorphisms in checkpoint kinase 2 may contribute to lymph node metastasis from esophageal cancer.

Esophageal cancer, which is commonly accompanied by lymph node metastasis, is among the deadliest of cancers and carries a grim prognosis. We investigated the association between genetic variation in checkpoint kinase 2 (CHEK2), which has been linked to metastasis in other cancers, and the risk of developing lymph node metastasis from esophageal cancer. CHEK2-122 G/C genotypes were determined by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) in 296 subjects with esophageal cancer (67 cases with and 229 cases without lymph node metastasis). The associations between CHEK2 genotypes and the risk of lymph node metastasis from esophageal cancer were estimated by computing odds ratios (OR) and their 95% confidence intervals (CI). The CHEK2 GG, GC, and CC genotype frequencies in patients with and without lymph node metastasis were 47.8%, 40.3%, and 11.9% and 31.0%, 50.7%, and 18.3% respectively, and were statistically significant (χ(2) =6.591, P=0.037). Logistic regression analyses revealed that the CHEK2-122 GC genotype significantly reduced the risk of lymph node metastasis (adjusted OR=0.54, 95% CI=0.29-0.93, P=0.028) compared to the GG genotype. Subsequently, we propose that the CHEK2-122 G/C polymorphism may play a protective role in preventing lymph node metastasis from esophageal cancer, and may also provide insight toward determining patient prognosis without the use of surgery.

Mutation of the epidermal growth factor receptor gene and its impact on the efficacy of gefitinib in advanced non-small cell lung cance.

Mutations in the epidermal growth factor receptor (EGFR) gene are associated with subsets of non-small cell lung cancer (NSCLC). Some patients with EGFR mutations are responsive to targeted therapy with the EGFR tyrosine kinase inhibitor gefitinib. Here, the mutation status of EGFR was assessed in advanced-stage NSCLC patients to determine how mutation status influences the clinical efficacy of gefitinib. The study included 106 patients with advanced NSCLC who were treated with gefitinib. Exons 19 and 21 of EGFR were sequenced from tumor tissues samples by PCR, and patient clinical characteristics, short-term outcomes (partial response, stable disease, progressive disease), and survival [overall survival (OS) and progression-free survival (PFS)] were compared. EGFR mutations in either exon 19 or exon 21 were detected in 54.7% of cases. The EGFR gene mutation rate was significantly different in patients with different pathological types (χ(2)=6.612, P<0.05). The distribution of short-term outcomes differed significantly by EGFR gene mutation status, history of smoking, and bone metastasis (χ(2)=6.481~35.938, P<0.05). Further, OS and PFS was significantly higher following gefitinib in patients with EGFR mutations than those without EGFR mutation (χ(2)=19.135, 6.953, P<0.05). OS was also significantly higher in patients with an exon 19 deletion mutation than in those with the exon 21 point mutation (χ(2)=8.575, P<0.05). Cox multivariate regression analysis indicated that OS was correlated with the pathological type of the tumor (HR=4.877), US Eastern Cooperative Oncology Group Physical Status (ECOG PS) score (HR=3.087), and EGFR mutation status (HR=1.876) (all P<0.05), while PFS was correlated with ECOG PS score (HR=2.218), cycles of chemotherapy (HR=1.829), and EGFR mutation status (HR=1.840) (all P<0.05). Only mild adverse events were reported during gefitinib treatment. The findings indicate that gefitinib treatment can improve the clinical outcomes of NSCLC patients with EGFR mutation, prolonging their survival time with only mild adverse events.

Adsorption of Cu(2+) and methyl orange from aqueous solutions by activated carbons of corncob-derived char wastes.

Corncob-derived char wastes (CCW) obtained from biomass conversion to syngas production through corncob steam gasification, which were often discarded, were utilized for preparation of activated carbon by calcination, and KOH and HNO3 activation treatments, on the view of environment protection and waste recycling. Their adsorption performance in the removal of heavy metal ions and dye molecules from wastewater was evaluated by using Cu(2+) and methyl orange (MO) as the model pollutant. The surface and structure characteristics of the CCW-based activated carbons (CACs) were investigated by N2 adsorption, CO2 adsorption, FT-IR, and He-TPD. The adsorption capacity varied with the activation methods of CACs and different initial solution concentrations, indicating that the adsorption behavior was influenced by not only the surface area and porosity but also the oxygen functional groups on the surface of the CACs. The equilibrium adsorption data were analyzed with the Langmuir, Freundlich, and Temkin isotherm models, and the adsorption kinetics was evaluated by the pseudo-first-order and pseudo-second-order models.