Figure 5.
Generation of cisplatin-resistant HNSCC cell lines. (A) Schematic drawing for establishing cisplatin-resistant SCC15 cells. The cells were treated step-wise with increasing doses of cisplatin for 48 hr followed by recovery for at least 1 week. Three cisplatin-resistant cell lines, cisR-1, cisR-2, and cisR-3, were generated. (B) Parental and the three cisplatin-resistant clones were treated with increasing doses of cisplatin for 48 hr and cell viability was measured by WST-1 assay. (C) GRP78 protein expression level was determined by Western blot analysis with GAPDH serving as loading control. (D) Left panel: GRP78 mRNA expression level was determined by quantitative RT-PCR after normalization against β-actin mRNA. Right panel: Quantitation of GRP78 protein levels in (C) after normalization against GAPDH. Data are presented as means ± S.D. (n=3). *P ≤ 0.05 (Student’s t test).