The invasive ability of cells was measured by transwell assays. The number of invasive cells was significantly lower in cells infected with let-7g mimics than that in cells infected with negative mimics, suggesting that enhanced expression of let-7g could inhibit OS cells invasion in vitro. The tumor invasive promotion mediated by anti-let-7g was partly inhibited by silencing Aurora-B in OS cells. (Columns, mean (n=6); bars, S.D. *P < 0.05, ΔP < 0.05 VS NC, ▲P < 0.05 VS NC and anti-let-7g.).