Epigenetic activation of tumor suppressor microRNAs in human cancer cells.

MicroRNAs (miRNAs) are small noncoding RNAs that function as endogenous post-transcriptional silencers of target genes. miRNAs are expressed in a tissue specific manner and play important roles in cell proliferation, apoptosis and differentiation during animal development. Recent studies have shown a distinct connection between aberrant expression of miRNAs and the development of cancer, suggesting that miRNAs can be potential therapeutic targets. Our recent study has shown that some miRNAs are controlled by epigenetic alterations such as DNA methylation and histone modification in human cancer cells. Activation of tumor suppressor miRNAs by chromatin modifying drugs may cause downregulation of target oncogenes and could be a novel strategy for the prevention and treatment of human cancer.