MicroRNA-98 and microRNA-214 post-transcriptionally regulate enhancer of zeste homolog 2 and inhibit migration and invasion in human esophageal squamous cell carcinoma.

BACKGROUND: The enhancer of zeste homolog 2 (EZH2) was found to be overexpressed and associated with tumor metastasis in esophageal squamous cell carcinoma (ESCC). On the other hand, it was reported that miR-26a, miR-98, miR-101, miR-124, miR-138 and miR-214 could inhibit the expression of EZH2 in some tumors. However, the role of miRNAs in the regulation of EZH2 expression in human ESCC has not been documented. The aim of this study was to determine the role of these miRNAs in the regulation of tumor metastasis via EZH2 overexpression in human ESCC. METHODS AND RESULTS: The expression of these miRNAs and EZH2 mRNA were examined by qPCR and the expression of EZH2 protein was detected by western blot. The role of these miRNAs in migration and invasion was studied in ESCC cell line (Eca109) transfected with miRNA mimics or cotransfected with miRNA mimics and pcDNA-EZH2 plasmid (without the 3'-UTR of EZH2). Through clinical investigation, we found that miR-98 and miR-214 expression was significantly lower in ESCC tissues than in matched normal tissues, and the expression level of miR-98 and miR-214 was inversely correlated to EZH2 protein expression and the clinical features such as pathological grade, tumor stage and lymph node metastasis in ESCC. In Eca109 cells, overexpression of miR-98 and miR-214 significantly inhibited the migration and invasion of ESCC cells, which was reversed by transfection of EZH2. CONCLUSIONS: These findings suggest that decreased expression of miR-98 and miR-214 might promote metastasis of human ESCC by inducing accumulation of EZH2 protein.

[Freeze resistance analysis of different wheat cultivars based on the relationships between physiological indices and grain yield].

A pot experiment with twenty wheat cultivars was conducted to investigate the superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities and the MDA, soluble protein and soluble sugar contents of functional leaves as well as the grain yield, 1000-grain weight, and grain morphological characters under low temperature stress. Low temperature (-4 degrees C) stress at stem elongation stage resulted in the changes of grain morphology and yield characters. For most of test cultivars, their grain length-width ratio, grain roundness, and sterile spikelets increased, and their grain equivalent diameter, grain area, 1000-grain weight, and grain yield decreased. Path analysis indicated that after treated with low temperature at stem elongation stage, the SOD activity and soluble sugar content of functional leaves, especially the SOD activity (direct path coefficient -0. 578) , were the dominant factors affecting grain yield. Taking the percentage of decreased grain yield due to low temperature stress as the assessment criterion, the test twenty winter wheat cultivars were divided into three groups. Cultivars Jimai 19, Jimai 20, Liangxing 99, Shannong 1135, Shannong 8355, Taishan 23, Taishan 9818, Wennong 6, and Yannong 21 belonged to high freeze resistance group, cultivars Linmai 2, Weimai 8, Yannong 19, and Zimai 12 were of low freeze resistance group, and the other seven cultivars belonged to medium freeze resistance group. The seedling stage comprehensive assessment index (D value) had a significant negative correlation with the percentage of decreased grain yield (r = -0. 512*), suggesting that the stronger freeze resistance of wheat at seedling stage was beneficial to the higher wheat grain yield, and seedling stage was the critical period to be selected to identify the freeze resistance of wheat.