Fig. 7
Inhibition of LU-HNSCC-26 growth using cisplatin (a), cetuximab (b) and ionizing radiation (c), and expression of epidermal growth factor receptor (EGFR) (d). A. The HPV-positive LU-HNSCC-26 (LU-HNSCC-26, grey circles) and three HPV-negative HNSCC cell lines (black symbols) were treated with increasing concentrations of cisplatin for one hour. After 5 days the cells were analyzed by the sulphorhodamine B (SRB) method. The data points were fitted to a sigmoidal dose-response equation yielding inhibitor concentration (IC50) values as indicated in Table 3. B. LU-HNSCC-26 cells were seeded in 96-well plates and treated with increasing concentrations of cetuximab for 5 days. Growth was analyzed with the SRB method and the data was treated as above. C. The four cell lines were irradiated with increasing doses and analyzed by the SRB method when the untreated controls were approximately 90% confluent. The data points were fitted to a sigmoidal dose-response equation yielding inhibitor dose (ID50) values as indicated in Table 3. In all panels (a-c), error bars indicate standard error of the mean. D. Cell lysates were prepared from all cell lines and probed with anti-EGFR. Expression was normalized to protein load and indicated as percentage of the expression in HN-4