Inhibition of miR-214 in OS cell lines markedly suppressed cell proliferation, migration and invasion. Phosphatase and tensin homolog (PTEN) was identified as a direct target of miR-214, and ectopic expression of miR-214 inhibited PTEN

MicroRNAs (miRNAs) are a class of small non-coding RNAs, which function as critical gene regulators by targeting mRNAs for translational repression or degradation, and they are essential in cancer development and progression. Several previous studies have indicated that abnormal expression of miRNAs occurs frequently in human osteosarcoma (OS) tissues compared with that of adjacent normal tissues. In the present study, the role of miR-214 in the progression and metastasis of OS was investigated. The expression of miR-214 was frequently increased in OS tissues and cell lines. Inhibition of miR-214 in OS cell lines markedly suppressed cell proliferation, migration and invasion. Phosphatase and tensin homolog (PTEN) was identified as a direct target of miR-214, and ectopic expression of miR-214 inhibited PTEN by directly binding to its 3'-untranslated region. The expression of miR-214 negatively correlated with PTEN in OS tissues. Together, these data indicated that miR-214 acts as an oncogenic miRNA and may contribute to the progression, and metastasis of OS, suggesting that miR-214 may be a potential novel diagnostic and therapeutic target of OS.