Fig 2: Slug mediates ERKi-induced EMT in NSCLC cells. (A-B) Effects of ERKi treatment on expression of EMT-TFs in NSCLC cell lines. A549 (A) and HCC827 (B) cells were treated with BVD or SCH at 2.5 µM for 5 days. The mRNA levels of a panel of EMT-TFs were examined using qRT-PCR. (C) Effect of ERKi treatment on SNAI2 expression in primary NSCLC cells. Primary tumor cells isolated from a NSCLC PDX (PDX72) were treated with BVD or SCH at 2.5 µM for 5 days, the mRNA level of SNAI2 was examined. (D) Effect of ERKi treatment on SNAI2 expression in multiple NSCLC cell lines. H460, H2122, and H2030 cancer cells with KRAS mutation and H838 cancer cells with wild-type KRAS were treated with BVD at 2.5 µM for 5 days, the mRNA level of SNAI2 was determined. (E) Effect of ERKi treatment on the protein level of Slug in NSCLC cell lines. A549 and HCC827 cells were treated with BVD or SCH at 2.5 µM for 5 days. Immunoblotting was conducted to determine the protein level of Slug. GAPDH was blotted as a loading control. (F-I) Effects of Slug knockdown on BVD-induced EMT. A549 cells were transfected with either control siRNA (siCtrl) or Slug siRNA (siSlug) pool for 24 h, then treated with BVD at 2.5 µM for 5 days. Immunoblotting was performed to determine the protein level of Slug (F). FACS was conducted to determine the presence of N-Cad+ cells (G), the percentage of N-Cad+ cells in each group was plotted (H). Immunofluorescence staining was conducted to determine E-Cad and Vimentin expression (I). (J-K) Effects of Slug knockdown on BVD-induced enhancement of the cell migration ability. siCtrl and siSlug transfected A549 cells were treated with BVD at 2.5 µM for 5 days. The wound healing assay was carried out to determine the migration ability of these cells (J), the relative wound closure was plotted (K). N = 3, bar: SD, *: P < 0.05; **: P < 0.01.