Epigenetic regulation of microRNAs in a hepatocellular carcinoma cell line

Emerging evidence indicates that microRNAs (miRNAs) are often deregulated in hepatocellular carcinoma (HCC) and that some specific miRNAs are associated with the initiation and progression of HCC. Although miRNAs plays important roles in HCC tumor formation, little is known about the mechanisms that control miRNA expression in HCC. To test if miRNA genes are targeted by epigenetic modifications, miRNA expression profiling was performed in the HCC cell line SK-HEP-1 treated or untreated with 5-AzaC (DNA hypomethylating agent). The results showed that the expression of 33 miRNAs was regulated by the epigenetic drugs. Considering the functional importance of miRNAs in tumorigenesis, it is clear that additional layers of control by miRNA function linked to the epigenetic regulators may exist during cancer development. A genome-wide miRNA microarray was used to identify differentially expressed miRNAs between 5μM 5-azacytidine-treated SK-HEP-1 (SK-2) cells and untreated SK-HEP-1 cells.