Fig. 3

Receptor tyrosine kinase (RTK) expression. a, quantitative RT-PCR on transmembrane receptors in HCT116, SW480 and HCT15 resistant cells compared with parental cell clones. Bars indicate fold-change compared to parental control. ***: p < 0.001. b, western blot analysis of RTKs and their phosphorylation status at baseline conditions in parental versus resistant cell lines. Tubulin was used for normalization of protein extract content. c, western blot analysis at 72 h after silencing of IGF1R, HER2 or HER3, showing the level of phosphorylation of the downstream effectors AKT and MAPK. Tubulin was used for normalization of protein extract content