Abnormally expressed circular RNAs as novel non-invasive biomarkers for hepatocellular carcinoma: A meta-analysis.

BACKGROUND: Circular RNAs (circRNAs) are a newly discovered class of endogenous non-coding RNAs that may have roles in cancer genesis and development. In the recent literature, dysregulated circRNAs have been extensively investigated in hepatocellular carcinoma (HCC). Whether or not circRNAs are of clinical value for the management of HCC has not been characterized. AIM: To meta-analyze the diagnostic and prognostic value of abnormally expressed circRNAs in HCC. METHODS: Eligible studies were sourced from PubMed, EMBASE, and CNKI online databases. Data on patients' clinical characteristics, including diagnostic efficacy and overall survival, were extracted. The diagnostic and prognostic parameters were respectively synthesized using the bivariate meta-analysis model and multivariate Cox hazard regression analysis based on Stata 12.0. The trim and fill method was adopted to assess the possible effects from publication bias. RESULTS: A total of 21 eligible studies were included. The pooled sensitivity, specificity, and area under the curve of abnormally expressed circRNAs in distinguishing HCC from non-cancer controls were 0.78 (95%CI: 0.69-0.85), 0.80 (95%CI: 0.74-0.86), and 0.86, respectively. Survival analyses showed that the down-regulated circRNA expression signature correlated perfectly with HCC survival [hazard ratio (HR) = 0.42, 95%CI: 0.19-0.91, P = 0.028; I 2 = 92.7%, P = 0.000], whereas the HCC cases with high circRNA levels had significantly poorer prognoses than those of patients with low circRNA levels (HR = 2.22, 95%CI: 1.50-3.30, P = 0.000; I 2 = 91%, P = 0.000). Moreover, abnormally expressed circRNAs were intimately associated with tumor size, differentiation grade, microvascular invasion, metastasis, TNM stage, and serum alpha fetal protein level in patients with HCC. Stratified analysis based on sample type, control source, and expression status also yielded robust results. CONCLUSION: Abnormally expressed circRNA signatures show immense potential as novel non-invasive biomarker(s) for HCC diagnosis and prognosis.

Expression of inositol-requiring enzyme 1ß is downregulated in azoxymethane/dextran sulfate sodium-induced mouse colonic tumors.

Inflammatory bowel disease (IBD) is a risk factor in colon cancer. Endoplasmic reticulum (ER) stress is associated with IBD and cancer. In the current study an azoxymethane (AOM) and dextran sulfate sodium (DSS)-induced mouse colonic tumor model was established to analyze the expression of ER stress chaperone molecules. Female C57BL/6 mice were intraperitoneally injected with 12 mg/kg AOM. On the 7th day following AOM injection, mice were treated with 1% DSS supplemented to the drinking water for 7 days, then followed by 14 days of normal drinking water. The cycle of 7 days DSS plus 14 days normal water was repeated twice and colonic tumors were evaluated for their number and size. Mice in the control group were injected with saline and received normal drinking water for the course of the experiment. mRNA levels of cytokines, inositol-requiring enzyme (IRE)1α and 1ß, their downstream targets X-box binding protein (XBP)1u, XBP1s and mucin (MUC) 2 and interleukin (IL)-6, IL-8 and tumor necrosis factor (TNF)-α were detected by reverse transcription-quantitative polymerase chain reaction. IRE1α, IRE1ß and MUC2 protein expression was evaluated by immunohistochemistry, and IRE1α and IRE1ß levels were further assessed by western blot analysis. It was observed that tumors developed in the distal colon of mice treated with AOM/DSS. IL-6, IL-8 and TNF-α mRNA levels were significantly increased in mice of the tumor group compared with mice of the control group. There were no significant differences in IRE1α mRNA and protein expression between the two groups and XBP1s mRNA levels were increased in the tumor compared with the control group. IRE1ß and MUC2 mRNA levels were significantly decreased in the tumor compared with the control group (decreased by 42 and 30%, respectively). IRE1ß and MUC2 proteins were predominately expressed in colonic epithelial cells and expression was decreased in the tumor compared with the control group. In conclusion, the downregulation of IRE1ß and MUC2 may reduce the ability of colon tissues to resist inflammation, thus promoting the occurrence and development of colonic tumors.

5-Hydroxytryptamine (5-HT)-exacerbated DSS-induced colitis is associated with elevated NADPH oxidase expression in the colon.

AIM: This study investigated the impact of 5-hydroxytryptamine (5-HT) on the expression of NOXs in dextran sulfate sodium (DSS)-induced colitis in mice. METHODS: C57BL/6J (B6) mice at 6 to 8 weeks of age were treated with 5-HT, DSS, or DSS + 5-HT. After 6-day treatment, the severity of colitis, infiltration of leukocytes, and messenger RNA (mRNA) and/or protein levels of Nox1, Nox2, Nox4, and Duox2 were analyzed in the colon by real-time quantitative polymerase chain reaction (qPCR), immunohistochemistry (IHC), and Western blot analysis. The direct effect of 5-HT on NOX gene and protein expression in HT-29 colon cancer cells and in U-937 macrophage cells were determined by qPCR and Western blot analysis. RESULTS: Mice treated with 5-HT alone did not develop colitis, while those treated with 1.0% DSS or DSS + 5-HT had mild and severe colitis, respectively. All treated mice had more myeloperoxidase-positive cells in the colon compared with untreated control mice. Mice treated with 5-HT or DSS alone had increased Nox2 and Nox4 mRNA and protein levels in the colon determined by qPCR, IHC, and Western blot analysis. These two Nox expressions were even higher in mice treated with DSS + 5-HT, while the expression levels of epithelium-localized Nox1 and Duox2 tended to decrease. Additionally, mice treated with 5-HT alone had elevated Nox1 and Duox2 expression as shown by qPCR and IHC. However, these gene expressions were diminished in DSS + 5-HT-treated mice likely due to erosion of epithelium. Furthermore, 5-HT induced NOX1 and DUOX2 gene and protein expression in HT-29 colon cancer epithelial cells, whereas induced NOX2 and NOX4 gene and protein expression in U-937 cells. CONCLUSION: As 5-HT induced NOX1 and DUOX2 gene and protein expression in colon epithelial and HT-29 cells, NOX2 and NOX4 in the infiltrating leukocyte in mouse colon and in U-937 cells, the exacerbate colitis induced by combined 5-HT and DSS treatment might be relevant to increased NOX expression in mice colons.

Mice Deficient in Cyp4a14 Have An Increased Number of Goblet Cells and Attenuated Dextran Sulfate Sodium-Induced Colitis.

BACKGROUND/AIMS: Cyp4a14 is a member of cytochrome P450 (Cyp450) enzyme superfamily that possesses NADPH monooxygenase activity, which catalyzes omega-hydroxylation of medium-chain fatty acids and arachidonic acid. Study suggests that down-regulation of Cyp4a14 has an anti-inflammatory response in intestine. The present study was to test the function of Cyp4a14 in dextran sulfate sodium (DSS)-induced colitis. METHODS: Female Cyp4a14-knockout (KO) and wild-type (WT) mice were treated with DSS for 6 days to induce colitis. The colon of mice was histologically observed by hematoxylin and eosin (H&E) and periodic acid Schiff (PAS) staining. The serum malondialdehyde (MDA), an endogenous indicator of oxidative stress, was chemically measured. Proinflammatory and NADPH oxidase genes were examined by quantitative polymerase chain reaction (qPCR). RESULTS: Cyp4a14-KO mice had a significantly higher number of goblet cells in the colon and were more resistant to DSS-induced colitis compared with the WT mice. The DSS-treated KO mice had lower levels of MDA. Consistent with the milder inflammatory pathological changes, DSS-treated KO mice had lower levels of IL-1ß, IL-6 and TNF-α mRNA in the liver and the colon. Moreover, the colon of DSS-treated Cyp4a14-KO and WT mice had higher mRNA levels of two members of NADPH oxidases, Nox2 and Nox4, suggesting that both Nox2 and Nox4 are inflammatory markers. By contrast, DSS-treated WT and KO mice had drastically decreased epithelium-localized Nox1 and dual oxidase (Duox) 2 mRNA levels, coinciding with the erosion of the mucosa induced by DSS. CONCLUSION: These results suggests a hypothesis that the increased goblet cell in the colon of Cyp4a14-KO mice provides protection from mucosal injury and Cyp4a14-increased oxidative stress exacerbates DSS-induced colitis. Therefore, Cyp4a14 may represent a potential target for treating colitis.