Circular RNA TTBK2 promotes the development of human glioma cells via miR-520b/EZH2 axis.

OBJECTIVE: Glioma is a highly malignant human disease characterized by limited response to clinical therapy. Evidence indicated that circular RNA Tau tubulin kinase 2 circular RNAs (circ-TTBK2) participated in glioma pathogenesis. However, the precise effect of circ-TTBK2 on glioma progression is needed to be highlighted. MATERIALS AND METHODS: The levels of circ-TTBK2, microRNA-520b (miR-520b), and enhancer of zeste homologue 2 (EZH2) were detected via quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) or Western blot. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay was performed to determine cell proliferation in vitro. Besides, a flow cytometry assay was conducted to examine apoptosis of A172 and U251 cells. Cell invasion was identified using the transwell assay. Moreover, Dual-Luciferase reporter assay was used to confirm the interaction between miR-520b and circ-TTBK2 or EZH2. The role of circ-TTBK2 in glioma progression was exposed using xenograft tumor experiments. RESULTS: The levels of circ-TTBK2 and EZH2 were markedly augmented, whereas miR-520b expression level was notably reduced in glioma tissues and cell lines. Either circ-TTBK2 or EZH2 detection could clearly facilitate cell apoptosis and block proliferation and invasion in A172 and U251 cells, while the effect of circ-TTBK2 or EZH2 deficiency was reverted by co-transfecting with miR-520 inhibitor. Moreover, circ-TTBK2 exerted its roles via miR-520b/EZH2 axis in glioma cells, and the knockdown of circ-TTBK2 could hinder the progression of glioma. CONCLUSIONS: Circ-TTBK2/miR-520b/EZH2 axis modulated cell proliferation, apoptosis, and invasion in glioma cell lines, and might serve as potential targets for glioma diagnosis and therapy.

MiR-15 suppressed the progression of bladder cancer by targeting BMI1 oncogene via PI3K/AKT signaling pathway.

OBJECTIVE: To investigate the role of microRNA-15 (miR-15) in the progression of bladder cancer (BC) cell and its underlying mechanism. PATIENTS AND METHODS: Human BC specimens were collected from BC patients during operations. BC cell lines (T24, BIU87, and HT1376) and normal uroepithelial cell lines SV-HUV-1 were cultured. The abilities of cell proliferation and invasion were detected by Methyl thiazolyl tetrazolium (MTT) and transwell assay, respectively. Additionally, the relevant mRNA and protein expressions were measured by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR), Western blot and immunohistochemistry, respectively. Furthermore, the luciferase reporter assay was used to verify the target gene of miR-15. Besides, Xenograft tumor formation assay was performed to confirm the effect of miR-15 on tumor growth. RESULTS: A low expression of miR-15 was detected by qRT-PCR, whereas the high expression of B cell-specific Moloney murine leukemia virus integration site 1 (BMI1) was detected by immunocytochemical assay in BC tissues. Moreover, miR-15 expression and BMI1 expression were significantly associated with the overall survival of BC patients. MTT and transwell assay results stated that the up-regulation of miR-15 inhibited BC cell proliferation, migration, and invasion. BMI-1 was verified as a direct target of miR-15 in BC using Luciferase reporter assay. Besides, miR-15 regulated epithelial-mesenchymal transition (EMT)-related makers, protein kinase B (AKT), and the phosphorylation of AKT protein levels in BC using the Western blot assay. Xenograft tumor formation assay indicated that the over-expression of miR-15 inhibited the tumor growth. CONCLUSIONS: We stated that miR-15 suppressed BC cell progression by targeting BMI1 through the phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway, which provided a potential target for BC treatment.

Isoflurane and sevoflurane affects Wnt/ß-catenin signaling pathways in hippocampal formation of neonatal rats.

OBJECTIVE: General anesthesia impairs spatial learning and memory in neonatal rats. The aim of this study was to investigate whether the Wnt pathway was involved in neonatal isoflurane and sevoflurane exposure-induced neurocognitive impairment. MATERIALS AND METHODS: Sprague-Dawley rats were randomly assigned to administration isoflurane or sevoflurane for 6 hours at postnatal 7 days. Wnt inhibitor XAV 939 was administrated 30 min before anesthesia. Morris water maze was used to test the learning and memory at 5-week and 10-week. Hematoxylin and Eosin (H&E) stain was performed to evaluation the neuronal death in the hippocampus. Quantitative Real-time PCR (q-PCR) and Western blot assays were used to measure mRNA and proteins expression levels of the Wnt3a, GSK 3ß and ß-catenin, respectively. RESULTS: The results showed that isoflurane or sevoflurane could significantly increase neonatal death and cell lost in the developing brain and the Wnt inhibitor could improve the cell degeneration. It demonstrated that isoflurane or sevoflurane could impair the P7 rats learning and memory capability, while these effects were reduced over time. When rats treated Wnt inhibitor at 30 min before anesthesia, the impairment of brain could relieve. q-PCR and Western blot demonstrated that isoflurane or sevoflurane affects expression levels of Wnt3a, GSK 3ß and ß-catenin. These results suggested that impairment of learning and memory in P7 rats may be related to the Wnt signaling pathway. CONCLUSIONS: The results suggested general anesthesia treatment led to increased brain cell degeneration and impaired learning and memory in P7 rats via Wnt signaling pathway.

An improved K-means clustering method for cDNA microarray image segmentation.

Microarray technology is a powerful tool for human genetic research and other biomedical applications. Numerous improvements to the standard K-means algorithm have been carried out to complete the image segmentation step. However, most of the previous studies classify the image into two clusters. In this paper, we propose a novel K-means algorithm, which first classifies the image into three clusters, and then one of the three clusters is divided as the background region and the other two clusters, as the foreground region. The proposed method was evaluated on six different data sets. The analyses of accuracy, efficiency, expression values, special gene spots, and noise images demonstrate the effectiveness of our method in improving the segmentation quality.

[Changes in gerbil brain tissue following cerebral ischemia and postischemic reperfusion and studies of the effects of the Chinese drugs].

With the animal model of cerebral ischemia and reperfusion, we conducted experiments on such model to study the effects of Ligustrazine(LZ) and Salvia Miltirrhizae(SM). The results obtained are as follows: (1) The ischemic brain showed hyperperfusion (congestion period) after 10 min reperfusion following 50 min of ischemia, and then entered a delayed hypoperfusion period after 60 minutes reperfusion and afterward the hypoperfusion was remained till the end of 120 min reperfusion. (2) Following 50 min of ischemic insult, ATP and glucose contents in brain tissue were almost depleted and much of lactate accumulated. Although rapid recovery of energy metabolism occurred within 60 min of reperfusion, a secondary deterioration emerged at 120 min of reperfusion. (3) Apparent brain edema occurred after cerebral ischemia and its further development was observed at the early stage of reperfusion owing to congestive response. Despite the degree of brain edema alleviated obviously after 60 min of reperfusion, the condition become worse at 120 min of reperfusion, which was accompanied by secondary metabolic deterioration. (4) Experimental results showed that LZ and SM could significantly elevate rCBF during the delayed hypoperfusion period, and limit the development of secondary deterioration in energy metabolism and brain edema after 120 min of reperfusion. (5) Notably, LZ and SM had no significant effect on MABP when these two Chinese drugs manifested their therapeutic actions in the animal model of cerebral ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)