Epigenetic Inactivation Of MicroRNA Gene MiR-615-5p In Pancreatic Cancer

ObjectiveDescribed the abnormal DNA methylation inhibits the miR-615-5p expression in pancreatic cancer cell line. Observe DNA methyltransferase inhibitor on the miR-615-5p in the pancreatic cancer cell line of the methylation status and expression.MethodFirst, aberrant hypermethylation of 5 miRNAs (miR-615-5p, miR-663, miR-663b, miR-675, and miR-1826) were shown in the pancreatic cancer cell line PANC-1 after miRNA microarray analysis. We chose miR-615-5p for further research. Then, to clarify the role of miR-615-5p in pancreatic cancer cell lines and pancreatic specimens, the relationship between the expression of miR-615-5p and methylation of its promoter region was evaluated by methylation-specific polymerase chain reaction (MSP) and bisulfite-sequencing PCR (BSP). Furthermore, the expression of miR-615-5p was analyzed in pancreatic cancer cell lines treated with 5-aza-2-deoxycytidine (5-Aza-CdR). ResultThe methylation level of miR-615-5p in the pancreatic cancer cell lines PANC-1, SW1990, and CFPAC-1 was significantly higher than in the pancreatic cancer cell line BXPC-3. The expression of miR-615-5p was inversely correlated with the methylation of its promoter region as measured by MSP and BSP. After treatment of PANC-1, SW1990, and CFPAC-1 cells with the demethylating agent 5-Aza-CdR, reduction of miR-615-5p methylation and concomitant reactivation of its expression could be observed.ConclusionThis study demonstrates that aberrant DNA methylation of the miR-615-5p CpG islands is closely linked to the inappropriate silencing of miR-615-5p in cancer cells, and may provide a valuable marker for improved detection of pancreatic cancer.