Fig 2: ETS-1 is involved in cisplatin resistance in HNSCC. a. Cal27 and Cal27CP cells were treated with increasing doses of cisplatin for 24 h, lysed, and analyzed for caspase-3 cleavage by Western blot with ß-Actin as loading control. b and d. Cal27CP (B) and UMSCC74B (d) cells were transfected with non-target siRNA or siRNA against ETS-1 for 24 h, treated with increasing doses of cisplatin for 24 h, and the expression of the indicated proteins was detected by Western blot. C and E. Cal27CP (c) and UMSCC74B (e) cells were transfected with non-target siRNA or siRNA against ETS-1 for 24 h, seeded into 6-well plates for 24 h, then treated with increasing doses of cisplatin for 72 h. Cell proliferation was measured by MTS assay

Fig 3: ETS-1 increases in cisplatin resistant HNSCC cells. a. IC50 values to cisplatin in the cisplatin-sensitive and resistant HNSCC cells are listed. Cells were treated with increasing doses of cisplatin for 72 h and IC50 values were determined. b. ETS-1 protein levels were examined in the indicated cells by Western blot analysis. The experiments were repeated for three times. Note: (S) indicates sensitivity to cisplatin and (R) indicates resistance to cisplatin. C. ETS-1 expression levels were examined in cisplatin-sensitive (Patient ID: 784116) and resistant (Patient ID: 871537) PDX by Western blot

Fig 4: ETS-1 is important in regulation of cisplatin-resistant HNSCC cell migration and invasion. Cal27CP cells were transfected with non-target siRNA or siRNA against ETS-1 for 48 h and cell migration (a) and invasion (b) were monitored with the xCELLigence real-time cell system. SFM: serum-free media

Fig 5: ETS-1 is regulated by SRC. a. Cell lysates prepared from Fig. 1b were re-used to test phosphorylation and total SRC by Western blot analysis. b. Cells were treated with different doses of Dasatinib for 8 h, lysed, and phosphorylation and total SRC and ETS-1 levels were detected by Western blot