MicroRNA-5 promotes osteosarcoma cell proliferation by targeting the cell-cycle inhibitor p27

Abstract

An increasing body of evidence indicates that microRNAs (miRNAs), a class of small non-coding RNAs, are often aberrantly expressed in human osteosarcoma. This study aimed to investigate the effects of miR-25 and to identify its potential target genes in osteosarcoma (OS) cells. First, the expression of miR-25 was detected by reverse transcription- quantitative polymerase chain reaction (RT-qPCR), which revealed a significant upregulation of miR-25 in osteosarcoma tissues compared to the adjacent healthy tissues. To investigate the role of miR-25 in osteosarcoma cell proliferation, the miR-25 precursor was next transfected into Saos-2 and U2OS cells. Overexpression of miR-25 promoted cell proliferation in vitro and tumor growth in a xenograft mouse model. In addition, our results revealed that the protein expression of p27, a cell-cycle inhibitor, is negatively regulated by miR-25. Restoring the p27 level in miR-25-overexpressing cells reversed the enhancing effect of miR-25 on cell proliferation. Therefore, miR-25 may act as an onco-miRNA in osteosarcoma, which provides new perspectives in cancer treatment strategies based on molecular targeting.