TP53 mutation is associated with PPP resistance in colorectal carcinoma cells. (A). Western blot analysis of the expression of IGF-1R protein in colorectal carcinoma tumor tissues (T) and matched adjacent normal colorectal tissue (N). β-actin was used as the protein loading control. (B). Western blot detection of IGF-1R protein in a panel of seven colorectal carcinoma cell lines as indicated on the top of the panel. (C). Each of the cell lines was treated with the indicated concentrations of PPP for 72 hours and then analyzed by cell viability assay. The experiment was repeated three times and the data presented as mean + SD (standard deviation). **, p < 0.01.