Methylation of the miR-126 gene associated with glioma progression.

Gliomas are the most common and the most malignant brain tumors, accouting for 45-55% of all intracranial tumors. The incidence of glioma worldwide is about 6-12 per 100,000. Recently, several studies showed that the activation of the oncogenes and the inactivation and/or loss of the tumor suppressor genes, especially for miRNA-21, let-7 and so on, are the most primary molecule event in gliomas. MicroRNAs (miRNAs) are a class of endogenously expressed small noncoding RNAs which are usually 21-23 nucleotides long. miRNAs regulate gene expression and play important roles in a variety of physiological and pathological processes, such as cell proliferation, differentiation and apoptosis. To date, Growing evidence has shown that mi RNAs are frequently dysregulated in human cancers and can act as both tumor suppressors and oncogenes. Along with the discovery of micro RNA, more and more research focusing on its relationship with glioma was carried out to investigate the biological features of glioma and to provide experimental evidence for glioma mechanism. In the present study, we aimed to verify the miRNA-126 down-regulation which showed in the results of glioma tissue miRNAs chip and discuss the miRNA-126 methylation in patients with glioma. A total of 50 samples from patients with glioma and 20 control samples from patients with cerebral trauma were included in this study. The expression levels of the miR-126 gene were detected using quantitative polymerase chain reaction (PCR), and the methylation status of miR-126 was examined using methylation-specific PCR-denaturing high-performance liquid chromatography (MSP-DHPLC). The expression level of miRNA-126 was found to be significantly higher in the control group (0.6134 ± 0.1214) than in the glioma group (0.2771 ± 0.1529; P < 0.05). The expression was also significantly elevated in low-grade gliomas (0.3117 ± 0.1474) compared with high-grade gliomas (0.1582 ± 0.1345; P < 0.05). In addition, increased methylation of miR-126 was found in 40% of glioma patients in our study (20/50 cases), resulting in significantly decreased miR-126 expression (0.1715 ± 0.1376; P < 0.05). Our results indicate that we verified successfully the miRNA-126 down-regulation phenomenon in patients with glioma which showed in the results of glioma tissue miRNAs chip and the miRNA-126 down-regulation through methylation in patients with glioma. So we could say that epigenetic modification is a crucial mechanism for controlling the expression of miR-126 in glioma.

Thiazide-sensitive Na+-Cl- cotransporter: genetic polymorphisms and human diseases.

The thiazide-sensitive Na(+)-Cl(-) cotransporter (TSC) is responsible for the major sodium chloride reabsorption pathway, which is located in the apical membrane of the epithelial cells of the distal convoluted tubule. TSC is involved in several physiological activities including transepithelial ion absorption and secretion, cell volume regulation, and setting intracellular Cl(-) concentration below or above its electrochemical potential equilibrium. In addition, TSC serves as the target of thiazide-type diuretics that are the first line of therapy for the treatment of hypertension in the clinic, and its mutants are also reported to be associated with the hereditary disease, Gitelman's syndrome. This review aims to summarize the publications with regard to the TSC by focusing on the association between TSC mutants and human hypertension as well as Gitelman's syndrome.

p53 polymorphism and p21WAF1/CIP1 haplotype in the intestinal gastric cancer and the precancerous lesions.

The development of intestinal gastric carcinoma involves several precancerous stages. The environmental factor plays an important role in gastric carcinogenesis, while the host's genetic makeup may influence the susceptibility to cancer. In this study we investigated correlations of the p53 variations at codon 72 and p21(WAF1/CIP1) haplotype with the risk of intestinal gastric carcinoma. Forty-eight intestinal gastric carcinoma cases (GC), 96 chronic atrophic gastritis (CAG), 96 intestinal metaplasia (IM) and 96 dysplasia (DYS) controls were enrolled in this study. The p53 codon 72 proline allele carriers were found to be more susceptible to progress to GC than to IM (OR = 2.22, 95%CI = 1.05-4.70, P = 0.038). Patients carrying homozygous p21(WAF1/CIP1) haplotype A, which contains the serine at codon 31, the cytidine at the 16th base of the second intron, and the cytidine at the 70th base of the exon 3 were more prone to develop GC than to reach the IM or DYS stage (IM versus GC, OR = 3.35, 95%CI = 1.11-10.15; DYS versus GC, OR = 3.27, 95%CI = 1.09-9.80, P = 0.035). The combination of p53 codon 72 variation with the p21(WAF1/CIP1) haplotype further distinguished the risk of GC from IM precancerous lesion (OR = 9.31, 95% CI = 1.77-48.85, P = 0.08). These results suggest that p53 and/or p21(WAF1/CIP1) genotype may influence the progression during gastric tumorigenesis.

Esophageal cancer in Chinese population: no polymorphism in codon 149 of P21(Waf1/Cip1) cyclin dependent kinase gene.

It has recently been suggested that people of the Indian population who carried the codon 149 polymorphism (GAT-->GGT) of P21(Waf1/Cip1) gene were more susceptible to esophageal cancer and oral cancer than the individuals without that polymorphism. Since esophageal cancer is a high incident neoplasm in China, we analysed the same codon of P21(Waf1/Cip1) in the Chinese population. Blood samples from 80 esophageal cancer patients and 80 normal blood donors were collected for DNA extraction. Methods of Polymerase Chain Reaction (PCR) and direct sequencing were used for detection of the polymorphism in codon 149 of P21(Waf1/Cip1). Bioinformatics analysis was also thoroughly performed for this gene. No polymorphism was found in all samples tested. Bioinformatics analysis revealed that the so-called polymorphism of codon 149 reported previously was a wrong one. In conclusion, no polymorphism exists in codon 149 of P21(Waf1/Cip1). It is not appropriate to use it as a susceptible site of the gene in cancer study.