Ho Gun Kim
Chonnam National University, Gwangju, South Korea
Title: DNA methylation of microRNA genes in gastric carcinoma and its clinicopathological association
Biography
Biography: Ho Gun Kim
Abstract
Background & Aim: To explore the role of epigenetic mechanisms in the down-regulation of miRNA genes, we examined the presence of DNA methylation-associated silencing of miRNAs in gastric carcinoma and observed that aberrant methylation of these miRNAs is associated with expression of target gene products. Materials & Methods: Th e extent of promoter methylation of has-miR-9-1, has-miR-9-3, has-miR-129-2 and has-miR-137 was assessed using methylation-specifi c polymerase chain reaction in 100 gastric carcinoma tissues and corresponding non-tumor tissues. Th e potential target gene products of miRNAs were studied by immunohistochemistry and the relationship between methylation profi les of miRNAs. Results: Methylation of the has-miR-9-3 and has-miR-137 CpG island was frequently observed in tumor tissues (89% and 86%, respectively) and non-tumor tissues in 100 gastric carcinoma patients (70% and 78%). However, methylation level of the has-miR-129-2 did not shown signifi cant diff erence in tumor tissues (97%) compared with non-tumor tissues (90%) and normal gastric tissues (90%). Expression of NF-κB and SOX4 protein, which are has-miR-9 and has-miR-129-2 potential target respectively, were inversely correlated with methylation level of miRNAs. Conclusion: Th e results suggest that specifi c miRNAs methylation in gastric carcinoma could be an important molecular mechanism causing loss of control of its target and it may be correlated with the high transcriptional activity of target gene. Epigenetic silencing of some miRNAs may involve in the early stage of gastric carcinogenesis.