Expression profiles of circular RNAs in human colorectal cancer based on RNA deep sequencing.

BACKGROUND: Circular RNAs (circRNAs) are a novel group of RNAs and play essential roles in cancers. However, the expression profiles of circRNAs in human colorectal cancer (CRC) are largely unclear. METHODS: The differentially expressed circRNAs, mRNAs, and microRNAs (miRNAs) between CRC tissues and paired adjacent normal tissues were first screened. Then, gene ontology and pathway analyses were performed to predict the possible functions. In addition, we identified the differentially expressed circRNAs in CRC correlated with Krüppel-like factor 4 (KLF4) and validated their expression levels in CRC tissues. Finally, the correlations between hsa_circ_0142527 expression levels and clinicopathological features of patients with CRC were also analyzed. RESULTS: After filtered 4735 circRNAs by RNA deep sequencing, 67 differentially expressed circRNAs (fold change >2.0, P < 0.05) were selected. The top two pathways were cell cycle and other glycan degradation. Hsa_circ_0142527 and KLF4 mRNA were significantly lower expressed in CRC tissues in both training and confirm groups and have high positive correlation (r = 0.754). We further found that the expression levels of hsa_circ_0142527 were significantly associated with age (P = 0.004), differentiation (P = 0.008), invasion (P = 0.029), distal metastasis (P = 0.004), TNM stage (P = 0.005), and carcinoembryonic antigen (CEA; P = 0.037). CONCLUSIONS: The circRNA expression profile of CRC provided new clues for understanding the occurrence of CRC. Hsa_circ_0142527 may be served as a potential biomarker for the diagnosis of CRC.

Differential expression of circular RNAs in hepatic tissue in a model of liver fibrosis and functional analysis of their target genes.

AIM: To measure the expression profile of circular RNA (circRNA) in hepatic tissues in a liver fibrosis model and to explore their function using molecular biology and bioinformatic techniques. METHODS: The classic CCl4 mouse liver fibrosis model was established alongside a normal control group. The circRNA expression profile of hepatic tissue from the two groups was compared using a high-throughput circRNA microarray. The differentially expressed circRNAs were identified, and real-time quantitative polymerase chain reaction (RT-qPCR) was used to verify a subset of the differentially expressed circRNAs (target genes). At the same time, the mouse oxidative stress injury, macrophage inflammation, and hepatic stellate cell activation models were established, and the expression of target circRNA in the above cells was measured by RT-qPCR. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to predict the biological functions of target genes. Finally, one of the circRNAs was selected and its cellular function was verified using siRNA. RESULTS: A total of 10 389 circRNAs were analyzed by microarray. Compared with the normal group, there were 69 circRNAs that were differentially expressed in the liver fibrosis model group (>2-fold differential expression, P < 0.05), of which 14 were upregulated and 55 were downregulated. Five circRNAs and their differential expression were verified by RT-qPCR, and the findings were consistent with the microarray results. Of these, three circRNAs were differentially expressed (P < 0.05) in the JS1 model, one circRNA was differentially expressed (P < 0.05) in the AML12 model, and four circRNAs were differentially expressed (P < 0.05) in the RAW264.7 model. The GO analysis showed that the differentially expressed circRNAs might be involved in cell autophagy, composition of extracellular matrix components, synthesis and metabolism of retinoic acid, retinol dehydrogenase activity, ubiquitin-like protein ligase activity, histone methylation, and other biological functions. The KEGG analysis showed that the target genes of the differentially expressed circRNAs might be involved in transforming growth factor-ß1/smads, Hippo, Rap1, vascular endothelial growth factor, and other signaling pathways. Lipofection experiments showed that the expression of α-smooth muscle actin (α-SMA) in JS1 cells increased significantly after the expression of mmu_circ_34116 was decreased. CONCLUSION: The circRNA expression profile in liver fibrosis tissue shows significant changes. Partially differentially expressed circRNA could be involved in hepatic fibrosis related to hepatic oxidative stress injury, macrophage inflammation, and stellate cell activation. For instance, mmu_circ_34116 can significantly inhibit the activation of hepatic stellate cells.

Preliminary screening and functional analysis of circular RNAs associated with hepatic stellate cell activation.

OBJECTIVE: To screen for circular RNAs (circRNAs) that are associated with the activation of hepatic stellate cell (HSC) by monitoring changes in liver circRNA expression in a model of liver fibrosis. METHODS: The classic mouse model of CCl4-induced liver fibrosis was established and validated by histopathological examination. JS1 cells were activated by TGF-ß1 to model HSC activation in vitro. Differentially expressed circRNAs in the fibrotic liver tissues and JS1 cells were determined using circRNA microarray, and some of those circRNAs were verified by RT-qPCR. The target genes of the above circRNAs were then predicted by bioinformatics analysis and summarized into a "circRNA-miRNA-mRNA" network diagram. Constructed plasmid mmu_circ_34116 siRNA was transfected to JS1 cells by Lipo2000, then we detected the expression changes of α-SMA. RESULTS: A total of 10,389 circRNAs were identified by microarray screening, and 69 differentially expressed circRNAs were detected in the fibrotic liver tissues with >2-fold difference in expression level relative to normal liver tissues (P < 0.05); 14 circRNAs were up-regulated and 55 were down-regulated. Five differentially expressed circRNAs in fibrotic liver and JS1 cells were verified by RT-qPCR, while all five showed similar trends with the microarray results in the liver, only 3 circRNAs in the JS1 activation model were consistent with the microarray results while one showed no significant change and one circRNA was not detected. Bioinformatics analysis predicted that the "mmu_circ_34116/miR-22-3P/BMP7" signal axis might be involved in the activation of HSC. Transfection experiment confirmed that the expression of α-SMA is significantly elevated as a result of inhibitory expression of mmu_circ_34116. CONCLUSION: The circRNAs expression profile of liver tissue had changed in fibrosis mouse model, and some of these circRNAs may be associated with HSC activation. For instance, mmu_circ_34116 would inhibit HSC activation.

p16 Methylation was associated with the development, age, hepatic viruses infection of hepatocellular carcinoma, and p16 expression had a poor survival: A systematic meta-analysis (PRISMA).

BACKGROUND: Loss of tumor suppressor gene p16 expression via promoter methylation has been reported in hepatocellular carcinoma (HCC). This meta-analysis was conducted to evaluate the correlation between p16 methylation and HCC. Additionally, we also analyzed the potential prognostic role of p16 methylation, expression or alteration-associated HCC. METHODS: Online databases based on the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guideline were performed to analyze the role of p16 gene in HCC. The combined odds ratios (ORs) or hazard ratios (HRs) and their 95% confidence intervals (95% CIs) were summarized. RESULTS: Final 3105 HCCs and 808 non-tumor controls (chronic hepatitis and liver cirrhosis) were performed in this meta-analysis. p16 promoter methylation in HCC was significantly higher than in chronic hepatitis and chronic hepatitis in tissue and blood samples. In addition, p16 promoter methylation was notably higher in patients >50 years' old than in patients aged <50 years, and it was higher in hepatitis B virus (HBV) or hepatitis C virus (HCV)-positive HCC than in hepatic viruses-negative HCC. However, p16 promoter methylation was not correlated with sex, cirrhosis, tumor differentiation, clinical stage. No association was found between p16 methylation or alteration and the prognosis of patients with HCC in overall survival (OS) and disease-free survival (DFS). Although p16 expression was significantly correlated with a poor prognosis in OS and DFS (P < .05) CONCLUSIONS:: Our results indicate that p16 methylation was linked to the development, age, HBV, and HCV infection of HCC. p16 methylation or alteration was not associated with the prognosis, but p16 expression was linked to a poor survival.

Retrospective study: The diagnostic accuracy of conventional forceps biopsy of gastric epithelial compared to endoscopic submucosal dissection (STROBE compliant).

Conventional forceps biopsy (CFB) is the most popular way to screen for gastric epithelial neoplasia (GEN) and adenocarcinoma of gastric epithelium. The aim of this study was to compare the diagnostic accuracy between conventional forceps biopsy and endoscopic submucosal dissection (ESD).Four hundred forty-four patients who finally undertook ESD in our hospital were enrolled from Jan 1, 2009 to Sep 1, 2015. We retrospectively assessed the characteristics of pathological results of CFB and ESD.The concordance rate between CFB and ESD specimens was 68.92% (306/444). Men showed a lower concordance rate (63.61% vs 79.33%; P = 0.001) and concordance patients were younger (P = 0.048). In multivariate analysis, men significantly had a lower concordance rate (coefficient -0.730, P = 0.002) and a higher rate of pathological upgrade (coefficient -0.648, P = 0.015). Locations of CFB did not influence the concordance rate statistically.The concordance rate was relatively high in our hospital. According to our analysis, old men plus gastric fundus or antrum of CFB were strongly suggested to perform ESD if precancerous lesions were found. And young women with low-grade intraepithelial neoplasia could select regular follow-up.