Fig. 4.

ERK1/2 kinase phosphorylation analysis for the exploration of the mode of action of targeted therapies against HSNCC. a Immunoblot analysis performed upon short-term culture of a representative HNSCC tumour. Sample fragments obtained from tumour #5 were processed and analysed by immunoblotting for the indicated markers, with β-actin used as a loading control. b Dendrogram analysis based on the pERK / ERK ratio calculated for each condition. For each condition, an immunoblot analysis was performed on one slice cultured as indicated. Normalization of pERK/ERK ratio was applied in order to minimize the impact of the heterogeneity of individual tumours, by setting the value of the pERK/ERK ratio to 1 for control conditions. Following this normalization, a cluster analysis was performed in order to identify drugs with neighbouring activities on ERK phosphorylation. Bold and italic characters indicate conditions with a greater than 50 % inhibition of ERK phosphorylation