miR-519d acts as a EMT regulator in OSCC. (A) HN4 or HN30 cells were transfected with miR-NC, miR-519d or miR-519d plus MMP3 plasmid. The protein levels of MMP3, E-cadherin, N-cadherin and Vimentin in these cells were measured by western blotting at 72 h after transfection. (B) HN4 or HN30 cells were transfected with NC inhibitor, miR-519d inhibitor or miR-519d inhibitor plus MMP3 siRNA. Western blotting showed the protein expression of MMP3, E-cadherin, N-cadherin and Vimentin in these cells at 72 h after transfection. (C) HN4 or HN30 cells were transfected with miR-NC, miR-519d or miR-519d plus MMP3 plasmid. Then immunofluorescence experiment was performed to detect the protein expression of MMP3, E-cadherin, N-cadherin and Vimentin in these cells (Scare bar: 20 μm). (D) OSCC cells (HN4 and HN30) were transfected with NC inhibitor, miR-519d inhibitor or miR-519d inhibitor plus MMP3 siRNA, and the expression of MMP3, E-cadherin, N-cadherin and Vimentin in tumor cells were measured using immunofluorescence (Scare bar: 20 μm).