Down-regulation of miR-300 in cells having undergone EMT. A.,B. Morphology, E-cadherin and Vimentin expression levels and invasive behavior analysis of HN-4 cells, HN-12 cells and TGF-β-treated HN-4 cells (A) or MCF-7 cells, MDA-MB-231 cells and TGF-β-treated MCF-7 cells (B). Left panel showed the phase contrast microscopy and immunofluorescence staining of E-cadherin and Vimentin in the indicated cells. Right-upper panel showed the invasive behavior of the indicated cells in transwell assays. Right-lower panel showed the Western blot analysis of E-cadherin and Vimentin protein levels in the indicated cells. C. Fifteen miRNAs, including miR-300, were confirmed down-regulated in the HNSCC cells that underwent EMT by real-time PCR. D. The down-regulation of miR-300 was also observed in breast cancer cells that underwent EMT. * P < 0.05.