Downstream pathways regulating TF expression in CRC cells. (A) TF protein levels in mutant K-ras-dependent HCT116 cells were diminished by selective inhibition of the PI3K and MAPK pathways using LY294002 and PD98059, respectively. Specific inhibition of EGFR and ErbB2 kinases with CI-1033, a pan-ErbB inhibitor, slightly decreased TF levels, whereas PDGFR inhibition (AG1296) had no effect. (B) Similar results were observed in 379.2 cells, which have altered p53 function in addition to mutant K-ras. Inhibitor concentrations used were as follows: AG1296 (20 μM), CI-1033 (10 μM), PD98059 (50 μM), and LY294002 (20 μM).