Aberrant hypermethylation induced downregulation of antisense lncRNA STXBP5-AS1 and its sense gene STXBP5 correlate with tumorigenesis of glioma.

AIMS: The expression of antisense lncRNA STXBP5-AS1 and its sense gene STXBP5 were found to be downregulated in glioma by RNA sequencing; however, the function and mechanism of both two genes in the development of glioma have not been studied. MATERIALS AND METHODS: QRT-PCR and western blot were used to determine the transcriptional and translational levels of moleculars. MSP and BSP assays were used to evaluate the methylation status of promoter CpG island. MTT, EdU, flow cytometry, and transwell assays were used to reveal biological effects. The in vivo mice model was used to validate the role of target genes in tumorigenesis. KEY FINDINGS: The mRNA and protein expression of STXBP5 was significantly downregulated in glioma tissues and positively correlated with prognosis. STXBP5-AS1 was downregulated in glioma cells and tissues, and associated with tumor size and clinical stages. Both of two genes were significantly restored in cells treatment with 5-Aza. The promoter CpG island of STXBP5/STXBP5-AS1 was hypermethylated in glioma cells, but partially methylated in NHA cells. We found that promoter methylation frequency was significantly higher in glioma tissues. Functionally, overexpression of STXBP5 and STXBP5-AS1 inhibited cell proliferation, migration, and invasion and promoted apoptosis in vitro, whereas depletion of STXBP5 and STXBP5-AS1 showed opposite effects. Both the mRNA and protein expression of STXBP5 were positively regulated by STXBP5-AS1. Ectopic expression of STXBP5 and STXBP5-AS1 suppressed tumor formation in vivo. SIGNIFICANCE: Our findings suggested that epigenetically silenced STXBP5-AS1 and STXBP5 might act as novel tumor suppressors of glioma.

Expression of microRNA-184 in glioma.

The aim of the present study was to examine the expression of microRNA (miRNA)-184 in gliomas with different pathological grades, and its effect on survival prognosis. For the present study, 40 participants were selected with different pathological grades of glioma tissues with grade I (n=10), grade II (n=8), grade III (n=16), and grade IV (n=6). In addition, 10 cases of normal brain tissue (obtained by decompression because of traumatic brain injury) were selected. RT-PCR and immunohistochemical techniques were used to detect the expression level and intensity of miRNA-184 in different grades of glioma tissues. The length of survival of miRNA-184-positive patients was analyzed. miRNA-184 mRNA expression was found in normal tissues and tumor tissues, and the expression in tumor tissues was significant (P<0.05). Statistically significant differences of miRNA-184 expression were observed among different grades (P<0.05). miRNA-184 expression increased with the increase of grade level. The differences in expression across grade levels was statistically significant (P<0.05). A positive expression was not related to the pathological types of glioma cells. The median survival time of patients with miRNA-184-positive expression was significantly shorter than that of the negative expression group (P<0.05). miRNA-184 is highly expressed in gliomas, which is positively correlated with pathological grade, and is not correlated with pathological type, and negatively correlated with survival time. Thus, miRNA-184 is a potentially important molecular marker for glioma.

[Study on the association of thrombin activatable fibrinolysis inhibitor and the Thr325Ile and Thr147Ala polymorphisms of its encoding gene CPB2 in patients with coronary heart disease].

OBJECTIVE: To investigate the association of thrombin activatable fibrinolysis inhibitor (TAFI) and its encoding gene CPB2 polymorphism in patients with coronary heart disease (CHD). METHODS: The CPB2 gene polymorphisms of Thr325Ile and Thr147Ala were analyzed with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in patients of acute myocardial infarction (n=100), acute angina pectoris (n=110) and a control group (n=190). The antigen (Ag) and activity (Act) of the TAFI were determined by sandwich enzyme link immunosorbent assay specific for human TAFI and chromogenic assay for activated human TAFI in plasma, respectively. The relationship between Thr325Ile and Thr147Ala gene polymorphism and TAFI Ag and Act were also analyzed. RESULTS: Plasma TAFI Act and TAFI Ag in acute myocardial infarction group and acute angina pectoris group (CHD patients group) were both significantly higher than those of the control group. The genotype frequencies of Thr325Ile (C1040T) and Thr147Ala (G505A) were as the following: C1040C (Thr325Thr) 67 (31.9%) and 64 (33.6%); C1040T (Thr325Ile) 109 (51.9%) and 92 (48.4%); T1040T (Ile325Ile) 34 (16.2%) and 34(17.8%); G505G (Ala147 Ala) 75 (35.7%) and 72 (37.8%); G505A(Thr147Ala) 112 (53.3%) and 96 (50.5%); A505A(Thr147Thr)23 (10.9%) and 22 (11.7%), in the CHD patients and control respectively. Chi-square analysis showed no significant difference in the Thr325Ile and Thr147Ala polymorphism distributions (P > 0.05). In addition, at the 325 position, the TAFI antigen of the Thr325Thr was higher than that of the other genotypes (Thr325Ile and Ile325Ile, P < 0.05). There was no statistical significance between the TAFI antigen of the Thr325Ile and Ile325Ile (P > 0.05). No significant correlation was found between the TAFI Act and the Thr325Ile polymorphism. At the position 147, significant correlation between the polymorphism of the Thr147Ala and TAFI Ag and Act was not found. CONCLUSION: TAFI plays an important role in anti-fibrinolysis. It might be a risk factor for acute myocardial infarction and acute angina pectoris. The Thr325Ile polymorphism had obvious effect on TAFI antigen levels, but the Thr325Ile and Thr147Ala polymorphism had no association with coronary heart disease.