Figure 2

Pharmacological inhibition of JNK1/2 activation with SP reverses the mesenchymal phenotypes of KB/VCR cells. A. KB/VCR cells display enhancement level of p-JNK1/2 and p-c-Jun when compared to KB cells. The expression of p-JNK1/2, p-c-Jun and their total proteins was analyzed by Western blot with specific antibodies, using antibody to β-actin as a loading control. B. Suppression of JNK signaling by SP inhibits the phosphorylation of JNK1/2 and c-Jun in KB/VCR cells. KB/VCR cells were treated with SP (10 μM) for 24 h, and the proteins were then harvested for western blot analysis as mentioned in materials and methods. C. Exposure of KB/VCR cells to SP 10 μM for 24 h renders the KB/VCR cells losing the mesenchymal fibroblastic morphology and recovering epithelial cobblestone phenotype. (×10). D. Treatment of KB/VCR cells with SP recovers the expression pattern of epithelial and mesenchymal markers in KB/VCR cells similar to those in KB cells. KB/VCR cells treated with SP (10 μM) for 24 h were lysed and used for western blot analysis of EMT protein markers. Proteins extracted from KB cells were used as a control. E-F. Interfering with JNK1/2 by use of SP inhibited the migration (E: *P < 0.05 compared to KB; **P < 0.05 compared to control) and invasion (F: *P < 0.05 compared to KB; **P < 0.001 compared to control) of KB/VCR cells in response to serum. Cells were loaded into upper well, while the SP (10 μM) was added together with medium containing 10% FBS to the lower wells. Data are expressed as average ± SD of results obtained from three separated experiments. In all cases, blots are representative of three to four independent experiments.