Epigenetic control of the expression of a primate-specific microRNA cluster in human cancer cells.
Many of the known microRNAs (miRNAs) are encoded by polycistronic transcripts and are thought to be co-expressed. In this study, we discovered that the expression of a large miRNA cluster (C19MC) on human chromosome 19 is upregulated by the demethylating agent, 5-aza-2'-deoxycytidine (5-Aza-dC), in AGS gastric cancer cells. We found that C19MC was rarely expressed in most cells, but its expression was restored through DNA demethylation. We confirmed that this miRNA cluster was mainly expressed in the placenta, as previously reported. Furthermore, its expression pattern was highly correlated with the methylation state of a distal CpG-rich region located about 17.6 kb upstream of the miRNA cluster. Using combined bisulfite restriction analysis (COBRA) and bisulfite-sequencing techniques, we determined that this CpG-rich region is hypermethylated in the AGS and HeLa cells, but hypomethylated in the placenta tissue. In conclusion, we demonstrated that the expression pattern of the C19MC was activated in human cancer cells through demethylation of a CpG-rich region.
Tsai
Kuo-Wang
KW
Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
Kao
Hsiao-Wei
HW
Chen
Hua-Chien
HC
Chen
Su-Jen
SJ
Lin
Wen-chang
WC
D000818:Animals; D045744:Cell Line, Tumor; D018899:CpG Islands; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D015972:Gene Expression Regulation, Neoplastic; D006367:HeLa Cells; D006801:Humans; D035683:MicroRNAs / Q000235:genetics*; D009369:Neoplasms / Q000235:genetics*
D035683:MicroRNAs