Figure 4.

The effects of panitumumab and other kinase inhibitors on FTD‐induced phosphorylation of EGFR and intracellular kinases in LIM1215 cells. LIM1215 cells were seeded onto six‐well plates and cultured for 24 h. (A) EGFR phosphorylation at specific residues was probed with each phospho‐specific EGFR antibody following a 24‐h treatment with FTD (3 μm), panitumumab (100 ng·mL ⁻¹), or their combination. Induction of thymidylate synthase expression was used as a marker of pharmacodynamic response to FTD. β‐Actin was used as a loading control. (B) LIM1215 cells were treated for 24 h with FTD (3 μm), panitumumab (100 ng·mL ⁻¹), the EGFR tyrosine kinase inhibitor erlotinib (1 μm), MEK inhibitor U0126 (10 μm), p38 MAPK inhibitor SB203580 (10 μm), PI3K inhibitor LY294002 (10 μm), or their combinations as indicated.