Demethylation of microRNA-142 induced by demethylation agents plays a suppressive role in osteosarcoma cells

Osteosarcoma (OS), the most common malignant bone tumor, occurs mainly in adolescents and young adults, with a morbidity of 5 cases per million. The expression levels of microRNAs (miRNAs) as tumor suppressors were recently found to be downregulated in OS. Certain alterations of miRNAs and the possible mechanisms through which miRNAs affect cell proliferation and migration in OS were recently found to be correlated with methylation epigenetic mechanisms. In this study, it was demonstrated that, due to hypermethylation, the expression level of miRNA-142 (miR-142) was significantly downregulated in OS tissues and cells compared with that in control samples. The present study demonstrated an increased expression of miR-142 in Saos-2 and MG63 cells treated with demethylation agents, suggesting that the effect of such agents on cell growth, inhibition of invasion and cell cycle retardation may be mediated by miR-142 in OS.