Figure 4.

Matrix metalloproteinase (MMP) 19 induces epithelial–mesenchymal transition (EMT) in vitro. (A) Quantitative reverse-transcriptase polymerase chain reaction was performed for markers of EMT in A549, H1299, and H522 cells 24 hours after transient transfection with MMP19 siRNA and full length MMP19 cDNA compared with control subjects (ACTA2 = α-smooth muscle actin; CDH2 = N-cadherin; FN1 = fibronectin 1; VIM = vimentin). Data were analyzed by t test, *P < 0.05, MMP19 silencing or overexpression compared with the scrambled control, or MMP19 overexpression compared with the mock control. (B) Immunoblots for the epithelial marker (CDH1 = E-cadherin) and mesenchymal markers (ACTA2, VIM, FN1, and CDH2) in A549 cell lysates from MMP19 cDNA and siRNA transiently transfected A549 cells and mock control. (C) Immunofluorescent staining of A549 cells for ACTA2 (green, top) and VIM (green, middle), and CDH1 (red). Cells were counterstained with DAPI (blue; original magnification ×400). (D) Microarray heatmap of EMT-relevant gene expression in stable MMP19-transfected A549 cells and mock control as described in the Methods section. (E) Quantitative reverse-transcriptase polymerase chain reaction was performed for markers of EMT following silencing or overexpression of MMP19 in the presence of the MMP inhibitor GM6001. GM6001 did not block differential expression of these EMT markers (*P < 0.05 compared with mock transfection control).